Venus is often refereed to as "Earth's sister planet", thanks to the number of things it has in common with our planet. As a terrestrial planet, it is similarly composed of silicate rock and metals - which are differentiated between a metal core and a silicate crust and mantle. It also orbits within our Sun's habitable zone, and had a similarly violent volcanic past. But of course, there are also some major difference between our two planets. For one, Venus has an atmosphere that is incredibly dense (92 times that of Earth, in fact) and reaches temperatures that are hot enough to melt lead. In addition, the planet's rotation is immensely slow by comparison, taking 243.025 days to complete a single rotation, and rotating backwards relative to Earth. When discussing Venus' rotation, it is important to note a certain distinction. Rotation is the time it takes a planet to spin once on its axis. This is different from a planet's revolution, which is the time it takes for a planet to orbit around another object (i.e. the Sun). So while it takes the Earth one day (24 hours) to rotate once on its axis, it takes one year (365.256 days) to revolve once around the Sun. Orbital Period: In Venus' case, things work a little differently. For starters, it orbits the Sun at an average distance of about 0.72 AU (108,000,000 km; 67,000,000 mi) with almost no eccentricity. In fact, with its farthest orbit (aphelion) of 0.728 AU (108,939,000 km) and closest orbit (perihelion) of 0.718 AU (107,477,000 km), it has the most circular orbit of any planet in the Solar System. The planet completes an revolution around the Sun every 224.65 Earth days, which means that a year on Venus last about 61.5% as long as a year on Earth. Evey 584 days, Venus completes an interior conjunction, where it lies between Earth and the Sun. It is at this point that Venus makes the closest approach to Earth of any planet, at an average distance of 41 million km. Rotational Period: Unlike most other planets in the Solar System, which rotate on their axes in an counter-clockwise direction, Venus rotates clockwise (called “retrograde” rotation). It also rotates very slowly, taking 243.025 Earth days to complete a single rotation. This is not only the slowest rotation period of any planet, it also means that a single day on Venus lasts longer than a Venusian year. And, as noted earlier, Venus' rotation is backwards, relative to Earth and the other bodies in the Solar System. Technically, this means that its rotational period is -243,025 days. It also means that if you could view the Solar System from the position above its celestial north pole, all of the planets in would appear to be rotating counter-clockwise - except Venus, which rotates in a clockwise direction. Also, if you could stand on the surface of Venus, you would witness the Sun rising in the west and setting in the east. But you would be waiting a very ling time to see this happen! Read on to find out why... Sidereal vs. Solar Day:. Another important thing to consider is the difference between a sidereal day and a solar day on Venus. A sidereal day corresponds to the amount of time it takes for a planet to rotate once on its axis, which in Venus' case takes 243.025 Earth days. A solar day, by contrast, refers to the amount of time it takes for the Sun to reappear at the same point in the sky (i.e. between one sunrise/sunset and the next). A Venusian Solar Day is the equivalent to 116.75 days on Earth, which means that it takes almost 117 days for the sun to rise, set, and return to the same place in the sky. Doing the math, we then see that a single year on Venus (224.65 Earth days) works out to just 1.92 Venusian (solar) days. Not exactly the basis for a good system of dates, is it? Yes, when it comes to things like Venus' rotation, things are quite different than they are here on Earth. Not only does a day last over half a year on our "Sister Planet", but the Sun travels rises and sets on the opposite horizons, and travels across the sky in the opposite direction. The reason for this, according to astronomers, is that Venus billions of years ago (early in the planet's history) Venus was impacted by another large planet. The combined momentum between the two objects averaged out to the current rotational speed and direction, causing Venus to spin very slowly in its current retrograde motion. Someday, if human beings colonize there (perhaps in floating cities) they will have to learn to get used to a day that lasts over 2800 Earth hours, not to mention sunrises sunsets happening on the wrong horizon! We have written many interesting articles about Venus for Universe Today. Here's Interesting Facts About Venus, How Long is a Day on Venus?, How Long is a Year on Venus?, What is the Average Surface Temperature on Venus?, New Map Hints at Venus’ Wet, Volcanic Past and Venus Compared to Earth. Want more information on Venus? Here's a link to Hubblesite's News Releases about Venus, and here's a link to NASA's Solar System Exploration Guide on Venus. We have recorded a whole episode of Astronomy Cast that's only about planet Venus. Listen to it here, Episode 50: Venus.
If you follow some of my other shows, like Astronomy Cast and the Weekly Space Hangout. Of course you do, what a ridiculous thing to say… “if”. Anyway, since you follow those other shows, you know I’m currently obsessed with an upcoming observatory called the Large Synoptic Survey Telescope.
Obsessions are best when they’re shared. So today, I invite you to become as obsessed as I am about the LSST.
In the past, astronomers focused on building bigger telescopes at more remote locations so they could peer more deeply into the past, to resolve the faintest objects, to see right to the edge of the observable Universe.
But there’s a whole other dimension to the Universe: time. And by taking advantage of time, astronomers have made some of the most momentous discoveries in the history of astronomy.
The Large Synoptic Survey Telescope is all about time. Watching the sky over and over, night after night, watching for anything that changes.
First, let’s talk about some of the kinds of discoveries that can be made when you’re watching the sky for changes.
Perhaps the best example of this is the Mira Variable. These are red giants at the very end of their stellar evolution, almost out of usable hydrogen to burn in their cores. As their stellar flame flickers out, the light pressure can no longer hold against the gravity pulling the star inward. The star compresses in on itself, raising the temperature and pressure, allowing more fusion. It flares up again, and brightens in our sky.
Astronomers discovered that there’s a very specific relationship to the brightness and rate that this brightening happens. In other words, if you know how often a Mira variable flares up, you know how intrinsically bright it is. And if you know how bright it is, you can calculate how far away it is. Even in other galaxies.
That’s what Edwin Hubble did when he surveyed Mira variables in other galaxies. He discovered that most galaxies are actually speeding away from us in all directions, leading to the theory of the Big Bang.
Thanks to time, we understand that we life in an expanding Universe that originated from a single point, 13.8 billion years ago.
Let me give you another example: the discovery of gamma ray bursts. In the 1960s, the US launched a group of satellites as part of the Vela Mission. They had no astronomical purpose, they were designed to watch for the specific gamma ray signature from an unauthorized nuclear weapons test. But instead of nuclear explosions, they detected massive blasts of gamma radiation coming from deep space. These blasts only last for a few seconds and then fade away, leaving a faint afterglow that also fades.
We now know that gamma ray bursts mark the deaths of the largest stars in the Universe, and the formations of new black holes. Other gamma ray bursts signal the collisions of exotic stellar remnants, like neutron stars and white dwarfs.
I can give you many more examples, where the dimension of time lead to a discovery in astronomy:
In 1930, Clyde Tombaugh compared pairs of photographic plates, switching back and forth over and over, looking for any object that moved position. This was how he discovered Pluto. In fact, this same technique is used by astronomers to find other dwarf planets, asteroids and comets to this day.
Astronomers return again and again to galaxies in the night sky, looking for any that have a new star in them. This is a tell tale sign of a supernova, the explosion of a star much more massive than our Sun. Some of these supernovae allowed astronomers to discover dark energy, that the expansion of the Universe is accelerating.
This is what time can help us discover.
Now, on to the Large Synoptic Survey Telescope. The observatory is currently under construction in north-central Chile, where many of the world’s most powerful telescopes are located.
Its main mirror is 8.4 meters across. Just for comparison, ESO’s Very Large Telescopes are 8.2 metres across. The Gemini Observatories are 8.1 metres across. The Keck Observatory is 10 metres wide. What I’m saying here, is that the LSST is plenty big.
But that’s not its most important feature. LSST is fast. When I say fast, I’m saying this in the astronomical sense, which means that it can gather a lot of light over a wide area on the sky in a very short amount of time. While Keck, for example, can focus incredibly deeply at a tiny spot in the sky, LSST gulps light across a huge region of the sky.
It’ll be able to see 3.5-degrees of the sky, every time it takes a picture. The Sun and the Moon are about 0.5-degrees across in the sky, so imagine a grid 7 moons across and 7 moons high.
It’ll take a 15-second exposure every 20 seconds. In the amount of time you’ll spend watching this video, the LSST could have taken dozens of high resolution images of the sky.
In fact, it’ll completely image the available sky every few nights. And then petabytes of data will be released onto the internet, available for astronomers to pore over.
Want to find asteroids, just look through the LSST records. Want to know how fast the Universe is expanding, dig through the data. LSST is going to look everywhere and anywhere every couple of nights, and then provide this data to scientists to make discoveries.
Assuming the construction isn’t delayed, the Large Synoptic Survey Telescope should see first light in 2019. Shortly after that, it’ll be disgorging mountains of astronomical data onto the internet.
And shortly after that, I suspect, we’ll start to hear everything the Universe was doing when we weren’t watching before. Because now, thanks to LSST, we’ll be watching all the time.
This week's Carnival of Space is hosted by Brian Wang at his Next Big Future blog. Click here to read Carnival of Space #467 And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to email@example.com, and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
Hosting an evening star party this summer? You're in for a treat. Starting later this week, all five naked eye planets (Mercury, Venus, Mars, Jupiter and Saturn) are visible in the evening sky at dusk for a brief few weeks. We had a similar lineup in the dawn sky earlier in 2016, as the Earth had all the inner planets in its forward-facing view — now, we see these same planets in our collective rear view mirror, as we lap Mars, Jupiter and Saturn on the inner track, while Mercury and Venus race to catch up with us. At their narrowest, the planets from Saturn to Mercury fit within a span just 75 degrees wide in the last half of August. A wide field all-sky shot should catch 'em all in the same frame at once. This isn't a 'grand conjunction' in a strict sense. To have all five planets visible, you need the slowest and outermost of the five — Jupiter and Saturn, with orbital periods of 11.9 and 29.5 years respectively — in the same general swath of sky. Both are headed towards conjunction on December 21st, 2020, making such groupings more frequent as they race past the other three. The next true quintuple grand conjunction occurs on September 8th, 2040, when all 5 planets span just 9.3 degrees of the sky... the closest span since September 18th, 1186! There's a lot to watch out for in the next few weeks. Here's a who's who of planets this July in August, from east to west: Saturn: shining at magnitude +0.4 in the constellation Ophiuchus, Saturn is fresh off of opposition on June 3rd. Riding high in the southeast at dawn, Saturn makes a close 4.4 degree pass near Mars on August 24th, and the pair makes a straight line completed by the bright star Antares on the same date. Mars: High to the south in the constellation Libra at dusk, Mars begins its slow dive into the dusk during the last half of 2016. Currently shining at a respectable magnitude -0.9, Mars passed opposition on May 22nd and is headed towards a grand opposition in 2018, nearly as close as the historic close pass of 2003. Jupiter: Sitting in the constellation Leo, Jupiter shines at magnitude -1.6 and is about 20-30 degrees above the southwestern horizon at dusk. Jupiter passed quadrature 90 degrees east of the Sun on June 4th and opposition for 2016 on March 8th. Venus: The bashful planet of the group, Venus is slowly appearing from behind the Sun low in the dusk and headed for a brilliant dusk apparition later in 2016 and early 2017. Currently 3 degrees east of the Sun on July 31st, Venus reaches greatest elongation 47 degrees east of the Sun on January 12th, 2017. We've just been able to begin spying Venus using binocs last week from the rooftop of our Casablanca Air BnB. Follow that planet, as Venus makes a close 6' pass near Jupiter on August 27th. Mercury: And the innermost planet makes five, as Mercury reaches greatest elongation 27 degrees east of the Sun on August 16th. When can you first catch sight of Mercury, completing the fivesome? Jupiter and Venus actually make great bookends in the hunt, as +0.5 magnitude Mercury wanders between them through early August. It's too bad dusk twilight obscured the view this past weekend, as both Mercury and Venus photobombed the Beehive Cluster M44 in Cancer. Mercury also passes 20' from the bright star Regulus on July 30th. But wait, there's more. The Moon passes New on August 2nd, entering back into the dusk sky. The one day old Moon will pass the grouping of Venus, Regulus and Mercury on the evening of August 4th, actually occulting (passing in front of) Mercury for the southernmost tip of South America. The Moon then moves on to occult Jupiter for good measure on August 6th for the South Pacific and southeast Asia in the daytime. Finally, the waxing gibbous Moon makes a wide pass near Mars, Antares and Saturn on the evening of August 12th, on the same evening that the 2016 Perseids are due to occur. The Moon also reaches the nearest apogee (think 'closest far point') of the year, at 404,265 kilometers from the Earth on August 10th and reaches Full on August 18th, featuring a subtle penumbral eclipse and the start of eclipse season 2 of 2 for 2016. More on all of these events in the coming weeks. So, if you find yourself out hunting Pokémon G0 creatures 'til the late dusk hours this summer, don't forget to look up at the greatest show in the solar system!
The post See All Five Naked Eye Planets in the Dusk Sky at Once appeared first on Universe Today.
SpaceX Nails Mesmerizing Midnight Launch and Land Landing of Falcon 9 Carrying Critical ISS Science and Docking Port
KENNEDY SPACE CENTER, FL - In a breathtaking feat mesmerizing hordes of thrilled spectators, SpaceX nailed today’s (July 18) back to back post midnight launch and landing of the firms Falcon 9 first stage tasked to carry a cargo Dragon loaded with over two tons of critical science, supplies and a crew docking port to the space station for NASA. Liftoff of the SpaceX Falcon 9 rocket in its upgraded, full thrust version and the Dragon CRS-9 resupply ship took place right on time at 12:45 a.m. EDT Monday, July 18, from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. SpaceX simultaneously successfully delivered over 5000 pounds (2200 kg) of research supplies to orbit for NASA in a commercial cargo Dragon ship, as the primary mission goal - and soft landed the approximately 60,000 pound Falcon 9 first stage on land, as the experimental secondary mission goal. “The Falcon 9 first stage we landed is in excellent shape,” Hans Koenigsmann, SpaceX vice president of Flight Reliability, told Universe Today at the 2 a.m. EDT post launch and landing media briefing early this morning. See my launch and landing streak shot and photos herein, including deployment of the four landing legs in the final seconds before propulsive touchdown. The twin accomplishments will have far reaching implications for the exploration and exploitation of space for all humanity. “Each commercial resupply flight to the space station is a significant event. Everything, from the science to the spare hardware and crew supplies, is vital for sustaining our mission,” said Kirk Shireman, NASA’s International Space Station Program manager. “With equipment to enable novel experiments never attempted before in space, and an international docking adapter vital to the future of U.S. commercial crew spacecraft, we’re thrilled this Dragon has successfully taken flight.” The CRS-9 mission is to support the resident six-person crew of men and women currently working on the station from the US, Russia and Japan. The propulsive soft landing of the 156 foot tall Falcon 9 first stage of the Falcon 9 rocket on land at Cape Canaveral Air Force Station’s Landing Zone 1, located a few miles south of launch pad 40. The dramatic ground landing at LZ -1 took place about 9 minutes after liftoff. The first and second stages separated about two and a half minutes after liftoff and were easily visible to any eyewitness watching - backdropped by the sunshine states dark skies. As the second stage soared to orbit, the first stage reignited a first stage engine for a series on burns targeting a return to the Cape. We spotted the first engine firing about two mintues before landing, as it descended directly overhead of myself and everyone in the Cape Canaveral region. For a few moments it looked like it was headed right towards us, but then steered away as planned with engines blazing to slow the boosters descent to make a gentle landing at LZ-1. Finally the Falcon landed, obscured by a big vapor cloud and sonic booms roaring around the space coast - and waking many local residents. Several folks told me they were suddenly woken by the shocking booms reverberating inside their homes. Some area residents even called 911 not knowing the true nature of the noises. Among the wealth of over 3900 pounds (1790 kg) of research investigations loaded on board Dragon is an off the shelf instrument designed to perform the first-ever DNA sequencing in space, and the first international docking adapter (IDA) that is absolutely essential for docking of the SpaceX and Boeing built human spaceflight taxis that will ferry our astronauts to the International Space Station (ISS) in some 18 months. CRS-9 counts as the company’s ninth scheduled flight to deliver supplies, science experiments and technology demonstrations to the International Space Station (ISS). The CRS-9 mission is for the crews of Expeditions 48 and 49 to support dozens of the approximately 250 science and research investigations in progress under NASA’s Commercial Resupply Services (CRS) contract. Dragon reached its preliminary orbit about 10 minutes after launch. Then it deployed a pair of solar arrays and began a carefully choreographed series of thruster firings to reach the space station. If all goes well, Dragon is scheduled to arrive at the orbiting outpost on Wednesday, July 20, after a 2 day orbital chase. NASA astronaut Jeff Williams will then reach out with the station’s 57.7-foot-long Canadian-built robotic arm to grapple and capture the private Dragon cargo ship working from a robotics work station in the station’s cupola. NASA astronaut Kate Rubins will serve as Williams backup. She just arrived at the station last week on July 9 for a minimum 4 month stay, after launching to orbit on a Russian Soyuz on July 6 with two additional crew mates. Ground commands will be sent from Houston to the station’s arm to install Dragon on the Earth-facing bottom side of the Harmony module for its stay at the space station. The crew expects to open the hatch a day later after pressurizing the vestibule in the forward bulkhead between the station and Dragon. Live coverage of the rendezvous and capture July 20 will begin at 5:30 a.m. on NASA TV, with installation coverage set to begin at 9:45 a.m. CRS-9 marks only the second time SpaceX has attempted a land landing of the 15 story tall first stage booster. The history making first time successfully took place at Landing Zone 1 (LZ 1) on Dec. 22, 2015 as part of the ORBCOMM-2 mission. Landing Zone 1 is built on the former site of Space Launch Complex 13, a U.S. Air Force rocket and missile testing range. SpaceX also successfully recovered first stages three times in a row at sea this year on an ocean going drone ship barge using the company’s OCISLY Autonomous Spaceport Drone Ship (ASDS) on April 8, May 6 and May 27. Altogether SpaceX has successfully landed and recovered 5 first stage booster intact and upright. Watch for Ken’s onsite CRS-9 mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida. Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news. Ken Kremer …………. Learn more about Juno at Jupiter, SpaceX CRS-9 rocket launch, ISS, ULA Atlas and Delta rockets, Orbital ATK Cygnus, Boeing, Space Taxis, Mars rovers, Orion, SLS, Antares, NASA missions and more at Ken’s upcoming outreach events: July 18, 26-28: “SpaceX launches to ISS on CRS-9, Juno at Jupiter, ULA Delta 4 Heavy and Atlas V spy satellite launches, SLS, Orion, Commercial crew, Curiosity explores Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
Going into space comes with its share of risks. In addition to the possibility of a catastrophic failure happening during take-off or landing, and having your craft pinholed by a micrometeorite, there are also the dangers of spending extended periods in space. Beyond that, there are also the slow, degenerative effects that spending an extended amount of time in a weightless environment can have on your body. While astronauts on the ISS have enough space for the work-out equipment they need to help reduce these effects (i.e. muscle degeneration and loss of bone density), long-range missions are another matter. Luckily, NASA has plans for how astronauts can stay healthy during their upcoming "Journey to Mars". It's known as the Resistive Overload Combined with Kinetic Yo-Yo (ROCKY) device, which will be used aboard the Orion spacecraft. For years, engineers at NASA and in the private sector have been working to create the components that will take astronauts to the Red Planet in the 2030s. These include the Space Launch System (SLS) and the Orion Multi Purpose Crew Capsule. At the same time, scientists and engineers at the Ohio-based Zin Technologies company - with the support of the NASA Human Research Program’s Exploration Exercise Equipment project - were busy developing the equipment needed to keep the Martian crews healthy and fit in space. One of the biggest challenges was making a device that is robust enough to provide a solid work-out, but still be compact and light-weight enough to fit inside the space capsule. What they came up with was ROCKY, a rowing machine-like tool that can accommodate both aerobic activity and strength training. Using loads that simulate up to 180 kg (400 pounds) of resistance, astronauts will be ale to perform excises like squats, deadlifts and heel raises, as well as upper body exercises like bicep curls and upright rows. In the past, astronauts aboard the ISS have relied on equipment like the Mini Exercise Device-2 or the Treadmill Vibration Isolation System (TVIS) to reduce the risks of bone-density loss and muscle degeneration. But as Gail Perusek - the deputy project manager for NASA’s Exploration Exercise Equipment project - explained, developing exercise equipment for the Journey to Mars required something new: “ROCKY is an ultra-compact, lightweight exercise device that meets the exercise and medical requirements that we have for Orion missions. The International Space Station’s exercise devices are effective but are too big for Orion, so we had to find a way to make exercising in Orion feasible.” The device can also be customized, and incorporates the best features from a second device known as the Device for Aerobic and Resistive Training (DART). These include a servo-motor programmed to deliver a load profile that feels very similar to free weights. The DART was developed by TDA Research, a Denver-based R&D company, with the support of NASA’s Small Business Innovation Research Program. It was evaluated alongside the ROCKY during the equipment selection process. In addition to being used for the crewed mission to Mars, the ROCKY device is likely to become a permanent feature aboard the Orion capsule, which will make it a mainstay for all of NASA's proposed long-duration missions. As Cindy Haven, the project manager for the Exploration Exercise Equipment Project, explained: “Our long-term goal is to develop a device that’s going to work for us for exploration. Between now and the mission, we’ll have different phases where we’re going to evaluate it for functionality, usability and durability to refine its design.” The ROCKY device will be tested for the first time on Exploration Mission-2 (EM-2), the first mission where the spacecraft will be launched with a crew aboard. Th ROCKY will be located near the side hatch of the spacecraft, which astronauts will use to get in and out of the capsule. After the Orion is launched, the crew’s seats will be collapsed to provide more interior space for the astronauts as they work out. And while the early missions using the Orion capsule will span only a few weeks at a time, staying fit will be important in the unlikely event that the astronauts need to get out of the crew module unassisted after splashdown. In the meantime, NASA will be spending the next few years refining the device to optimize it not only for near-term crewed Orion missions, but for potential uses on future long-duration missions. These will include the all-important launch where the Orion will dock with a habitat in the area of space around the moon. These missions are part of Phase II of NASA's Mars mission, which is known as the “Proving Ground” phase. Scheduled to begin in 2030, this phase will involve the last elements of the mission being launched to cis-lunar orbit, and then all the equipment being sent to near-Mars space for pre-deployment. The development team that will oversee future refinements will include engineers and scientists from Glenn Research Center in Cleveland, Ohio, and Johnson Space Center in Houston. In addition to building the hardware and ensuring that it is certified for flight, they will also be responsible for incorporating lessons learned from the development of equipment built for the ISS. If all goes well in the coming years, the team even plans to include ROCKY into the International Space Station's already impressive array of workout machines. Just another way for the astronauts to beat the slow, degenerative effects of floating freely in space! Further Reading: NASA
The post ROCKY Exercise Device Will Help Keep Deep Space A Fit Place appeared first on Universe Today.
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Messier 19 globular star cluster. Enjoy! In the 18th century, while searching the night sky for comets, French astronomer Charles Messier began noticing a series of “nebulous objects” in the night sky. Hoping to ensure that other astronomers did not make the same mistake, he began compiling a list of these objects,. Known to posterity as the Messier Catalog, this list has come to be one of the most important milestones in the research of Deep Sky objects. One of these objects is Messier 19, a globular star cluster located in the constellation Ophiuchus. Of all the known globular clusters, M19 appears to be one of the most oblate (i.e. flattest) in the night sky. Discovered by William Herschel, this cluster is relatively difficult to spot with the naked eye, and appears as a fuzzy point of light with the help of magnification. Description: Speeding away from us at a rate of 146 kilometers per second, this gravitationally bound ball of stars measuring 140 light years in diameter, is one of the Messier globular clusters that has the distinction of being closest to the center of the Milky Way. At a little more than 5000 light-years from the intense gravitation of our own galactic core, it has played havoc on M19's round shape. In essence, Milky Way's gravity has caused M19 to become one of the most oblate of all globular clusters, with twice as many stars along the major axis as along the minor. And, although it is 28,000 light-years from Earth, it's actually on the opposite side of the galactic core. For all of its rich, dense mass, four RR Lyrae variable stars have been found in M19. Is Messier 19 unique? It has some stellar branch properties that are difficult to pinpoint. And even its age (though estimated at around 11.9 billion years old) is indeterminate. Says F. Meissner and A. Weiss in their 2006 study, "Global fitting of globular cluster age indicators": "The determination of globular cluster (GC) ages rests on the fact that colour-magnitude diagrams (CMDs) of single-age single composition stellar populations exhibit specific time-dependent features. Most importantly, this is the location of the turn-off (TO), which – together with the cluster’s distance – serves as the most straightforward and widely used age indicator. However, there are other parts of the CMD that change their colour or brightness with age, too. Since the sensitivity to time is different for the various parts of the cluster CMD, it is possible to use either the various indicators independently, or the differences in colour and brightness between pairs of them; these latter methods have the advantage of being independent of distance." What's occurring is a horizontal branch gap - an not-quite explainable difference in the way the stars inside M19 are aging. However, science is looking for the answer. As G. Busso et al. explained in their 2008 paper titled "The Peculiar Horizontal Branch Morphology of the Galactic Globular Clusters NGC 6388 and NGC 6441": "I show that a possible solution of the puzzle is to assume that a small fraction of the stellar population in the two clusters is strongly helium enriched. The presence of two distinct stellar populations characterized by two different initial He contents can help in explaining the brightness difference between the red portion of the HB and the blue component." Is helium the answer? Quite probably so. M. Salaris Astrophysics Research Institute and an international team of researchers explained in their 2004 study "The initial helium abundance of the Galactic globular cluster system": "Based on a recently updated set of stellar evolution models, we performed an accurate statistical analysis in order to assess whether GGCs show a statistically significant spread in their initial He abundances, and whether there is a correlation with the cluster metallicity. As in previous works on the subject, we do not find any significant dependence of the He abundance on the cluster metallicity; this provides an important constraint for models of Galaxy formation and evolution. Apart from GGCs with the bluest Horizontal Branch morphology, the observed spread in the individual helium abundances is statistically compatible with the individual errors. This means that either there is no intrinsic abundance spread among the GGCs, or that this is masked by the errors. In the latter case we have estimated a firm upper limit of 0.019 to the possible intrinsic spread. In case of the GGCs with the bluest Horizontal Branch morphology we detect a significant spread towards higher abundances inconsistent with the individual errors; this can be fully explained by additional effects not accounted for in our theoretical calibrations, which do not affect the abundances estimated for the clusters with redder Horizontal Branch morphology." History of Observation: M19 was one of Charles Messier's original discoveries, which he first observed on June 5th, 1764. In his notes, he wrote: "I have discovered a nebula, situated on the parallel of Antares, between Scorpius and the right foot of Ophiuchus: that nebula is round & doesn't contain any star; I have examined it with a Gregorian telescope which magnified 104 times, it is about 3 minutes of arc in diameter: one sees it very well with an ordinary refractor of 3 feet and a half. I have observed its passage of the Medirian, and compared it with that of the star Antares; I have determined the right ascension of that nebula of 252d 1' 45", and its declination of 25d 54' 46" south. The known star closest to that nebula is the 28th of the constellation Ophiuchus, after the catalog of Flamsteed, of sixth magnitude." While Charles didn't resolve it, we must give him due credit for discovery, for its size wouldn't make it a particularly easy object given his optics. Later, in 1784, William Herschel would become the first to open up its true identity: "When the 19th of the Connoiss. is viewed with a magnifying power of 120, the stars are visible; the cluster is insulated; some of the small stars scattered in the neighborhood are near it; but they are larger than those belonging to the cluster. With 240 it is better resolved, and is much condensed in the centre. With 300 no nucleus or central body can be seen. The diameter with the 10 feet is 3'16", and the stars in the centre are too accumulated to be separately seen. It will not be necessary to add that the two last mentioned globular clusters, viewed with more powerful instruments, are of equal beauty with the rest; and from what has been said it is obvious that here the exertion of a clustering power has brought the accumulation and artificial construction of these wonderful celestial objects to the highest degree of mysterious perfection." While you may - or may not - resolve Messier 19's individual stars, even small telescopes can pick up on some of its ellipticity and larger telescopes will make out a definite blue tinge to its coloration. Before you yawn at viewing another globular cluster, remember that you are looking at the other side of our galactic center and think on the words about M19 from Admiral Symth. "The whole vicinity," he wrote, "afford a grand conception of the grandeur and richness even of the exterior creation; and indicate the beautious gradation and variety of the heaven of heavens. Truly has it been said, "Stars teach us as well as shine." This is near the large opening or hole, about 4deg broad, in the Scorpion's body, which WH [William Herschel] found almost destitute of stars." Locating Messier 19: Finding M19's location in binoculars is quite easy - it's less than a fistwidth (8 degrees) east of Antares (Alpha Scorpi). However, 'seeing' M19 in binoculars (especially smaller ones) is a little more problematic. The steadier the binoculars are, the better your chances, since it will appear almost stellar at first glance. A good indicator is to have optical double 26 Ophiuchi in the field at the 2:00 position and look for the star that won't quite come to focus in the 8:00 position. Star 26 also makes for a great finderscope lead when locating M19 in a telescope as well. Even for aperture sizes as small as 114mm, this globular cluster will show quite easily in a telescope and reveal its oblate nature. When aperture size increase to the 8" range, it will begin resolution and as it nears 12" or more, you'll pick up on blue stars. And for your convenience, here are the quick facts of M19: Object Name: Messier 19 Alternative Designations: M19, NGC 6273 Object Type: Class VIII Globular Star Cluster Constellation: Ophiuchus Right Ascension: 17 : 02.6 (h:m) Declination: -26 : 16 (deg:m) Distance: 28.0 (kly) Visual Brightness: 6.8 (mag) Apparent Dimension: 17.0 (arc min) We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects, , M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons. Be to sure to check out our complete Messier Catalog. And for more information, check out the SEDS Messier Database.
Ever since Galileo Galilei first observed Jupiter closely in 1610 using a telescope of his own design, scientists and astronomers have been immensely fascinated by the Jovian planet. Not only is it the Solar System's largest planet, but there are still things about this world - despite centuries of research and numerous exploration missions - that continue to mystify even our greatest minds. One of the main reasons for this is because Jupiter is so starkly different from what we Earth-dwellers consider to be normal. Between its incredible size, mass, composition, the mysteries of its magnetic and gravitational fields, and its impressive system of moons, its existence has shown us just how diverse planets can truly be. Size, Mass and Density: Earth's has a mean radius of 6,371 km (3,958.8 mi), and a mass of 5.97 × 1024 kg, whereas Jupiter has a mean radius of 69,911 ± 6 km (43441 mi) and a mass of 1.8986×1027 kg. In short, Jupiter is almost 11 times the size of Earth, and just under 318 times as massive. However, Earth's density is significantly higher, since it is a terrestrial planet - 5.514 g/cm3 compared to 1.326 g/cm³. Because of this, Jupiter's "surface" gravity is significantly higher than Earth normal - i.e. 9.8 m/s² or 1 g. While, as a gas giant, Jupiter has no surface per se, astronomers believe that within Jupiter's atmosphere where the atmospheric pressure is equal to 1 bar (which is equal to Earth's at sea level), Jupiter experiences a gravitational force of 24.79 m/s2 (which is the equivalent of 2.528 g). Composition and Structure: Earth is a terrestrial planet, which means it is composed of silicate minerals and metal that are differentiated between a metal core and a silicate mantle and crust. The core itself is also differentiated, between an inner core and outer core (which spins in the opposite direction of Earth's rotation). As one descends from the crust to the interior, temperatures and pressure increase. The shape of Earth approximates that of an oblate spheroid, a sphere flattened along the axis from pole to pole such that there is a bulge around the equator. This bulge results from the rotation of Earth, and causes the diameter at the equator to be 43 kilometers (27 mi) larger than the pole-to-pole diameter. In contrast, Jupiter is composed primarily of gaseous and liquid matter which is divided between a gaseous outer atmosphere and a denser interior. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements. The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere. The denser interior is composed of roughly 71% hydrogen, 24% helium and 5% other elements by mass. It is believed that Jupiter’s core is a dense mix of elements – a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. The core has also been inferred as being rocky, but this remains unknown as well. And much like Earth, temperatures and pressures inside Jupiter increase dramatically toward the core. At the “surface”, the pressure and temperature are believed to be 10 bars and 340 K (67 °C, 152 °F). In the region where hydrogen becomes metallic, it is believed that temperatures reach 10,000 K (9,700 °C; 17,500 °F) and pressures 200 GPa. The temperature at the core boundary is estimated to be 36,000 K (35,700 °C; 64,300 °F) and the interior pressure at roughly 3,000–4,500 GPa. Also like Earth, Jupiter's shape is that of an oblate spheroid. In fact, Jupiter's polar flattening is greater than that of Earth's - 0.06487 ± 0.00015 compared to 0.00335. This is due to Jupiter's rapid rotation on its axis, and is why the planet's equatorial radius is approximately 4600 km larger than its polar radius. Orbital Parameters: Earth has a very minor orbital eccentricity (approx. 0.0167) and ranges in distance from 147,095,000 km (0.983 AU) from the Sun at perihelion to 151,930,000 km (1.015 AU) at aphelion. This works out to an average distance (aka. semi-major axis) of 149,598,261 km, which is the basis of a single Astronomical Unit (AU). The Earth has an orbital period of 365.25 days, which is the equivalent of 1.000017 Julian years. This means that every four years (in what is known as a Leap Year), the Earth calendar must include an extra day. Though technically a full day is considered to be 24 hours long, our planet takes precisely 23h 56m and 4 s to complete a single sidereal rotation (0.997 Earth days). But combined with its orbital period around the Sun, the time between one sunrise and another (a Solar Day) is 24 hours. Viewed from the celestial north pole, the motion of Earth and its axial rotation appear counterclockwise. From the vantage point above the north poles of both the Sun and Earth, Earth orbits the Sun in a counterclockwise direction. Earth’s axis is tilted also 23.4° towards the ecliptic of the Sun, which is responsible for producing seasonal variations on the planet’s surface. In addition to producing variations in temperature, this also results in variations in the amount of sunlight a hemisphere receives during the course of a year. Meanwhile, Jupiter orbits the Sun at an average distance (semi-major axis) of 778,299,000 km (5.2 AU), ranging from 740,550,000 km (4.95 AU) at perihelion and 816,040,000 km (5.455 AU) at aphelion. At this distance, Jupiter takes 11.8618 Earth years to complete a single orbit of the Sun. In other words, a single Jovian year lasts the equivalent of 4,332.59 Earth days. However, Jupiter’s rotation is the fastest of all the Solar System’s planets, completing a single rotation on its axis in slightly less than ten hours (9 hours, 55 minutes and 30 seconds). Therefore, a single Jovian year lasts 10,475.8 Jovian solar days. Atmospheres: Earth’s atmosphere is made up of five main layers – the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere. As a rule, air pressure and density decrease the higher one goes into the atmosphere and the farther one is from the surface. However, the relationship between temperature and altitude is more complicated, and may even rise with altitude in some cases. The troposphere contains roughly 80% of the mass of Earth’s atmosphere, with some 50% located in the lower 5.6 km (3.48 mi), making it denser than all its overlying atmospheric layers. It is primarily composed of nitrogen (78%) and oxygen (21%) with trace concentrations of water vapor, carbon dioxide, and other gaseous molecules. https://youtu.be/BOA_yKsaYwM Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth’s meteorological phenomena (clouds, rain, snow, lightning storms) take place. The one exception is the Thermoposphere, where the phenomena known as Aurora Borealis and Aurara Australis (aka. The Northern and Southern Lights) are known to take place. As already noted, Jupiter's atmosphere is composed primarily of hydrogen and helium, with trace amounts of other elements. Much like Earth, Jupiter experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere create a light show that is truly spectacular. Jupiter also experiences violent weather patterns. Wind speeds of 100 m/s (360 km/h) are common in zonal jets, and can reach as high as 620 kph (385 mph). Storms form within hours and can become thousands of km in diameter overnight. One storm, the Great Red Spot, has been raging since at least the late 1600s. The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear. Jupiter is perpetually covered with clouds composed of ammonia crystals and possibly ammonium hydrosulfide. These clouds are located in the tropopause and are arranged into bands of different latitudes, known as “tropical regions”. The cloud layer is only about 50 km (31 mi) deep, and consists of at least two decks of clouds: a thick lower deck and a thin clearer region. There may also be a thin layer of water clouds underlying the ammonia layer, as evidenced by flashes of lightning detected in the atmosphere of Jupiter, which would be caused by the water’s polarity creating the charge separation needed for lightning. Observations of these electrical discharges indicate that they can be up to a thousand times as powerful as those observed here on the Earth. Moons: Earth has only one orbiting satellite, The Moon. It’s existence has been known of since prehistoric times, and it has played a major role in the mythological and astronomical traditions of all human cultures and has a significant effect on Earth's tides. In the modern era, the Moon has continued to serve as a focal point for astronomical and scientific research, as well as space exploration. In fact, the Moon is the only celestial body outside of Earth that humans have actually walked on. The first Moon landing took place on July 20th, 1969, and Neil Armstrong was the first person to set foot on the surface. Since that time, a total of 13 astronauts have been to the Moon, and the research that they carried out has been instrumental in helping us to learn about its composition and formation. Thanks to examinations of Moon rocks that were brought back to Earth, the predominant theory states that the Moon was created roughly 4.5 billion years ago from a collision between Earth and a Mars-sized object (known as Theia). This collision created a massive cloud of debris that began circling our planet, which eventually coalesced to form the Moon we see today. The Moon is one of the largest natural satellites in the Solar System and is the second-densest satellite of those whose densities are known (after Jupiter’s satellite Io). It is also tidally locked with Earth, meaning that one side is constantly facing towards us while the other is facing away. The far side, known as the “Dark Side”, remained unknown to humans until probes were sent to photograph it. The Jovian system, on the other hand, has 67 known moons. The four largest are known as the Galilean Moons, which are named after their discoverer, Galileo Galilei. They include: Io, the most volcanically active body in our Solar System; Europa, which is suspected of having a massive subsurface ocean; Ganymede, the largest moon in our Solar System; and Callisto, which is also thought to have a subsurface ocean and features some of the oldest surface material in the Solar System. Then there’s the Inner Group (or Amalthea group), which is made up of four small moons that have diameters of less than 200 km, orbit at radii less than 200,000 km, and have orbital inclinations of less than half a degree. This groups includes the moons of Metis, Adrastea, Amalthea, and Thebe. Along with a number of as-yet-unseen inner moonlets, these moons replenish and maintain Jupiter’s faint ring system. Jupiter also has an array of Irregular Satellites, which are substantially smaller and have more distant and eccentric orbits than the others. These moons are broken down into families that have similarities in orbit and composition, and are believed to be largely the result of collisions from large objects that were captured by Jupiter’s gravity. In just about every way imaginable, Earth and Jupiter could not be more different. And there are still many things about the Jovian planet that we do not yet fully understand. Speaking of which, be sure to stay tuned to Universe Today for the latest updates from NASA's Juno mission. We have written many interesting articles about the planets of the Solar System here at Universe Today. Here's Earth Compared to Mercury, Earth Compared to Venus, The Moon Compared to Earth, Earth Compared to Mars, Saturn Compared to Earth, and Neptune Compared to Earth. Want more information on Jupiter? Here's a link to Hubblesite's News Releases about Jupiter, and here's NASA's Solar System Exploration Guide. We have recorded a podcast just about Jupiter for Astronomy Cast. Click here and listen to Episode 56: Jupiter.
We all love that feeling of "being there" when it comes to missions to other planets. Juno's arrival at Jupiter, New Horizons' flyby of Pluto and the daily upload of raw images from the Mars Curiosity rover makes each of us an armchair explorer of alien landscapes. But there's always been something missing. Something essential in shaping our environment — sound. NASA recently gave the go-ahead for the Mars 2020 rover that will bristle with a new suite of science instruments including a microphone. Hallelujah! Finally, we'll get to listen to the sound of the Martian wind, the occasional whirl of dust devils, the crunch of rocks beneath the rover's wheels and even sharp pops from laser-zapped rocks! The staff and membership of The Planetary Society have been trying for 20 years to get a working microphone to the Red Planet. One flew aboard NASA’s Mars Polar Lander mission in 1998 but that probe crashed landed when its engine shut down prematurely during the descent phase. In 2008 the Society partnered with Malin Space Science Systems to include its next microphone in the descent imager package on the Mars Phoenix lander in 2008. While that mission was successful, the imager (along with its microphone) was turned off for fear it might cause an electrical problem with a critical landing system. Mission planners hoped it might be turned on later but whether it was a money issue or fear of shorting out other critical lander instruments, it never happened. Heartbreaking. One sound souvenir we did get from Phoenix comes to us from the European Space Agency's Mars which recorded the radio transmissions from the lander as it descended. The signals were then processed into audio within the range of human hearing. Give a listen, there's a music to it. The Mars 2020 mission, which is expected to launch in the summer of 2020 and land the following February, will search directly for signs of ancient Martian life as well as identify and cache samples and specimens at several locations on the surface for pick-up by later missions. The microphone would be housed with the rover's SuperCam, a souped-up version of Curiosity's ChemCam, which fires a laser at rocks and soils from a distance to analyze the resulting vapors for their elemental composition. SuperCam will also shoot a laser to vaporize rocks and spectroscopy to tease out their molecular and mineral composition. The microphone would be mounted on a tube sticking out of the electronics box housing SuperCam and used for scientific purposes but I suspect for public outreach as well. One of its more intriguing uses will be to record the 'snap' or 'pop' when a rock is struck with the laser. Based on the volume of the sound, scientists can estimate the specimen's mass. NASA plans to land the 1-ton rover using the same sky crane method that settled Curiosity to the surface in dramatic fashion. While the rover will be busy photographing the entry, descent and landing sequence, the microphone will record the ambient sound. Synched together, this should make for one of the most compelling videos ever! The microphone will also be used to augment studies of Martian weather (the aforementioned winds and dust devils) and listen to the rover's creaks, groans and whir of its motors as the car-sized machine rolls across the alternately sandy and rocky surface of Mars. The Planetary Society is collaborating with the SuperCam team to make the most of the microphone. Who knows what else we might hear? Exploding fireball overhead? Static electricity? Rhythmic winds? Blowing sand? Slime-slap of alien pseudopods? OK, probably not the last one, but new instruments often reveal completely unexpected phenomena. It's been hard as hell getting a microphone on a space mission. They've had to compete with other instruments considered more essential not to mention the precious space the device would take up and the burden of additional mass. Mission planners consider every fraction of a gram when building a space probe because getting it into Earth orbit and blasting it to a planet takes energy. Rockets only hold so much fuel! https://www.youtube.com/watch?v=wLgVu6kVx9w Your Voice on Mars You might wonder if Mars' atmosphere is thick enough to carry sound. The good news is that it is, but unlike Earth's much denser nitrogen-oxygen mix, Martian air is 100 times thinner and composed of 95% carbon dioxide. If you could snap off your helmet and talk out loud on the Red Planet, your voice would sound deeper and not travel as far. Scientists liken it to having a conversation at 100,000 feet (30,500 meters) above Earth's surface. Check out the crazy video for a simulation. Now that you've made it to the end of this story, sit back and pump up the volume. We'll have ears on Mars soon! https://www.youtube.com/watch?v=w9gOQgfPW4Y Pump Up the Volume by M|A|R|R|S
SpaceX Midnight Launch Carrying Crucial Docking Port and Science to ISS Set for July 18, Plus Loud Land Landing – Watch Live
KENNEDY SPACE CENTER, FL - The outlook is outstanding for a dramatic midnight blastoff of the next SpaceX commercial cargo Dragon jam packed with some 5000 pounds of critical payloads and research supplies for NASA and heading to the space station on Monday, July 18 - that also simultaneously features an experimental land landing that promises to rock loudly across the Florida space coast and one day slash launch costs. Dragon is carrying a crucial crew docking port absolutely essential for conducting future human space missions to the orbiting outpost as well as a host of wide ranging science experiments essential for NASA exploiting the space environment for research in low earth orbit and deep space exploration. Liftoff of the SpaceX Falcon 9 rocket in its upgraded, full thrust version and the Dragon CRS-9 resupply ship is targeted for 12:45 a.m. EDT Monday, July 18, from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. The CRS-9 mission is to support the resident six-person crew of men and women currently working on the station from the US, Russia and Japan. Spectators are filling local area hotels in anticipation of a spectacular double whammy sky show comprising a thunderous nighttime launch streaking to orbit - followed minutes later by a brilliant rocket flash and night landing back at the Cape of the Falcon first stage that will send sonic booms roaring all around the coast and surrounding inland areas. SpaceX has confirmed they are attempting the secondary mission of landing the 156 foot tall first stage of the Falcon 9 rocket on land at Cape Canaveral Air Force Station’s Landing Zone 1, located a few miles south of launch pad 40. The weather and technical outlook for the 229 foot-tall (70 meter) Falcon 9 looks fantastic at this time, a day before liftoff. The official weather forecast from Air Force meteorologists with the 45th Space Wing calls for a 90 percent chance of “GO” with extremely favorable conditions at launch time for liftoff of this upgraded, SpaceX Falcon 9. The only concerns are for Cumulus clouds building up and a chance of precipitation. And for added stargazers delight the night sky features a full moon. The SpaceX/Dragon CRS-9 launch coverage will be broadcast on NASA TV beginning at 11:30 p.m. EDT Sunday, July 17, with additional commentary on the NASA launch blog. SpaceX will also feature their own live webcast beginning approximately 20 minutes before launch at 12:25 a.m. EDT Monday, July 18 You can watch the launch live at NASA TV at - http://www.nasa.gov/nasatv You can watch the launch live at SpaceX Webcast at - spacex.com/webcast The launch window is instantaneous, meaning that any delays due to weather or technical issues will results in a minimum 2 day postponement. If the launch does not occur Monday, a backup launch opportunity exists on 12 a.m. Wednesday, July 20, just seconds after midnight, with NASA TV coverage starting at 10:45 p.m. EDT Tuesday, July 19. CRS-9 marks only the second time SpaceX has attempted a land landing of the 15 story tall first stage booster. The history making first time took place at Landing Zone 1 (LZ 1) on Dec. 22, 2015 as part of the ORBCOMM-2 mission. Landing Zone 1 is built on the former site of Space Launch Complex 13, a U.S. Air Force rocket and missile testing range. SpaceX also successfully recovered first stages three times in a row at sea this year on an ocean going drone ship barge using the company’s OCISLY Autonomous Spaceport Drone Ship (ASDS) on April 8, May 6 and May 27. SpaceX issued a statement describing how local area residents could hear sonic booms - similar to those heard during landings of NASA’s space shuttles. “There is the possibility that residents of northern and central Brevard County, Fla. may hear one or more sonic booms during landing. A sonic boom is a brief thunder-like noise a person on the ground hears when an aircraft or other vehicle flies overhead faster than the speed of sound,” said SpaceX. Who could be affected? “Residents of the communities of Cape Canaveral, Cocoa, Cocoa Beach, Courtenay, Merritt Island, Mims, Port Canaveral, Port St. John, Rockledge, Scottsmoor, Sharpes, and Titusville in Brevard County, Fla. are most likely to hear a sonic boom, although what residents experience will depend on weather conditions and other factors.” The sights and sound are certain to be thrilling- so catch it if you can! CRS-9 counts as the company’s ninth scheduled flight to deliver supplies, science experiments and technology demonstrations to the International Space Station (ISS). The CRS-9 mission is for the crews of Expeditions 48 and 49 to support dozens of the approximately 250 science and research investigations in progress under NASA’s Commercial Resupply Services (CRS) contract. SpaceX engineers conducted their standard static fire hold down test of the first stages Merlin 1D engines with the rocket erect at pad 40, this morning Saturday, July 16. The customary test lasts a few seconds and was conducted with the Dragon bolted on top at about 9:30 a.m. I saw the test while visiting atop neighboring Launch Complex 39B at the Kennedy Space Center - see photo. “All looks good,” reported Hans Koenigsmann, SpaceX vice president of Flight Reliability, at a media briefing this afternoon. “We expect a GO for launch.” Dragon will reach its preliminary orbit about 10 minutes after launch. Then it will deploy its solar arrays and begin a carefully choreographed series of thruster firings to reach the space station. If all goes well, Dragon will arrive at the orbiting outpost on Wednesday, July 20, after a 2 day orbital chase. NASA astronaut Jeff Williams will then reach out with the station’s 57.7-foot-long Canadian-built robotic arm to grapple and capture the private Dragon cargo ship working from a robotics work station in the station’s cupola. NASA astronaut Kate Rubins will serve as Williams backup. She just arrived at the station last week on July 9 for a minimum 4 month stay, after launching to orbit on a Russian Soyuz on July 6 with two additional crew mates. Ground commands will be sent from Houston to the station’s arm to install Dragon on the Earth-facing bottom side of the Harmony module for its stay at the space station. The crew expects to open the hatch a day later after pressurizing the vestibule in the forward bulkhead between the station and Dragon. Live coverage of the rendezvous and capture July 20 will begin at 5:30 a.m. on NASA TV, with installation coverage set to begin at 9:45 a.m. Perhaps the most critical payload relating to the future of humans in space is the 1,020-pound international docking adapter known as IDA-2 or International Docking Adapter-2. Here’s an early morning video view of Falcon 9 on the pad today. https://youtu.be/dSoHMJABthQ Video Caption: Early morning shots of CRS-9 ready for flight on Monday July 18 at 12:45 AM. Credit: USLaunchReport Watch for Ken’s onsite CRS-9 mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida. Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news. Ken Kremer …………. Learn more about Juno at Jupiter, SpaceX CRS-9 rocket launch, ISS, ULA Atlas and Delta rockets, Orbital ATK Cygnus, Boeing, Space Taxis, Mars rovers, Orion, SLS, Antares, NASA missions and more at Ken’s upcoming outreach events: July 15-18: “SpaceX launches to ISS on CRS-9, Juno at Jupiter, ULA Delta 4 Heavy spy satellite, SLS, Orion, Commercial crew, Curiosity explores Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
In 1929, Edwin Hubble forever changed our understanding of the cosmos by showing that the Universe is in a state of expansion. By the 1990s, astronomers determined that the rate at which it is expanding is actually speeding up, which in turn led to the theory of "Dark Energy". Since that time, astronomers and physicists have sought to determine the existence of this force by measuring the influence it has on the cosmos. The latest in these efforts comes from the Sloan Digital Sky Survey III (SDSS III), where an international team of researchers have announced that they have finished creating the most precise measurements of the Universe to date. Known as the Baryon Oscillation Spectroscopic Survey (BOSS), their measurements have placed new constraints on the properties of Dark Energy. The new measurements were presented by Harvard University astronomer Daniel Eisenstein at a recent meeting of the American Astronomical Society. As the director of the Sloan Digital Sky Survey III (SDSS-III), he and his team have spent the past ten years measuring the cosmos and the periodic fluctuations in the density of normal matter to see how galaxies are distributed throughout the Universe. And after a decade of research, the BOSS team was able to produce a three-dimensional map of the cosmos that covers more than six billion light-years. And while other recent surveys have looked further afield - up to distances of 9 and 13 billion light years - the BOSS map is unique in that it boasts the highest accuracy of any cosmological map. In fact, the BOSS team was able to measure the distribution of galaxies in the cosmos, and at a distance of 6 billion light-years, to within an unprecedented 1% margin of error. Determining the nature of cosmic objects at great distances is no easy matter, due the effects of relativity. As Dr. Eisenstein told Universe Today via email: "Distances are a long-standing challenge in astronomy. Whereas humans often can judge distance because of our binocular vision, galaxies beyond the Milky Way are much too far away to use that. And because galaxies come in a wide range of intrinsic sizes, it is hard to judge their distance. It's like looking at a far-away mountain; one's judgement of its distance is tied up with one's judgement of its height." In the past, astronomers have made accurate measurements of objects within the local universe (i.e. planets, neighboring stars, star clusters) by relying on everything from radar to redshift - the degree to which the wavelength of light is shifted towards the red end of the spectrum. However, the greater the distance of an object, the greater the degree of uncertainty. And until now, only objects that are a few thousand light-years from Earth - i.e. within the Milky Way galaxy - have had their distances measured to within a one-percent margin of error. As the largest of the four projects that make up the Sloan Digital Sky Survey III (SDSS-III), what sets BOSS apart is the fact that it relies primarily on the measurement of what are called "baryon acoustic oscillations" (BAOs). These are essentially subtle periodic ripples in the distribution of visible baryonic (i.e. normal) matter in the cosmos. As Dr. Daniel Eisenstein explained: "BOSS measures the expansion of the Universe in two primary ways. The first is by using the baryon acoustic oscillations (hence the name of the survey). Sound waves traveling in the first 400,000 years after the Big Bang create a preferred scale for separations of pairs of galaxies. By measuring this preferred separation in a sample of many galaxies, we can infer the distance to the sample. "The second method is to measure how clustering of galaxies differs between pairs oriented along the line of sight compared to transverse to the line of sight. The expansion of the Universe can cause this clustering to be asymmetric if one uses the wrong expansion history when converting redshifts to distance." With these new, highly-accurate distance measurements, BOSS astronomers will be able to study the influence of Dark Matter with far greater precision. "Different dark energy models vary in how the acceleration of the expansion of the Universe proceeds over time," said Eisenstein. "BOSS is measuring the expansion history, which allows us to infer the acceleration rate. We find results that are highly consistent with the predictions of the cosmological constant model, that is, the model in which dark energy has a constant density over time." In addition to measuring the distribution of normal matter to determine the influence of Dark Energy, the SDSS-III Collaboration is working to map the Milky Way and search for extrasolar planets. The BOSS measurements are detailed in a series of articles that were submitted to journals by the BOSS collaboration last month, all of which are now available online. And BOSS is not the only effort to understand the large-scale structure of our Universe, and how all its mysterious forces have shaped it. Just last month, Professor Stephen Hawking announced that the COSMOS supercomputing center at Cambridge University would be creating the most detailed 3D map of the Universe to date. Relying on data obtained by the CMB data obtained by the ESA’s Planck satellite and information from the Dark Energy Survey, they also hope to measure the influence Dark Energy has had on the distribution of matter in our Universe. Who knows? In a few years time, we may very well come to understand how all the fundamental forces governing the Universe work together. Further Reading: SDSIII
The post Dark Energy Illuminated By Largest Galactic Map Ten Years In The Making appeared first on Universe Today.
NASA has spotted an enormous black blotch growing on the surface of the Sun. It looks eerie, but this dark region is nothing to fear, though it does signal potential disruption to satellite communications. The dark region is called a coronal hole, an area on the surface of the Sun that is cooler and less dense than the surrounding areas. The magnetic fields in these holes are open to space, which allows high density plasma to flow out into space. The lack of plasma in these holes is what makes them appear dark. Coronal holes are the origin of high-speed solar winds, which can cause problems for satellite communications. The images were captured by the Solar Dynamics Observatory (SDO) on July 11th. Tom Yulsman at Discover's ImaGeo blog created a gif from several of NASA's images. [embed]https://www.youtube.com/watch?v=hMVAIy17XFs[/embed] High-speed solar winds are made up of solar particles which are travelling up to three times faster than the solar wind normally does. Though satellites are protected from the solar wind, extremes like this can still cause problems. Coronal holes may look like a doomsday warning; an enormous black hole on the surface of our otherwise placid looking Sun is strange looking. But these holes are a part of the natural life of the Sun. And anyway, they only appear in extreme ultraviolet and x-ray wavelengths. The holes tend to appear at the poles, due to the structure of the Sun's magnetosphere. But when they appear in more equatorial regions of the Sun, they can cause intermittent problems, as the high-speed solar wind they generate is pointed at the Earth as the Sun rotates. In June 2012, a coronal hole appeared that looked Big Bird from Sesame Street. The Big Bird hole was the precursor to an extremely powerful solar storm, the most powerful one in 150 years. Daniel Baker, of the University of Colorado's Laboratory of Atmospheric and Space Physics, said of that storm, "If it had hit, we would still be picking up the pieces." We were fortunate that it missed us, as these enormous storms have the potential to damage power grids on the surface of the Earth. It seems unlikely that any solar wind that reaches Earth as a result of this current coronal hole will cause any disruption to us here on Earth. But it's not out of the question. In 1989 a solar storm struck Earth and knocked out power in the province of Quebec in Canada. It may be that the only result of this coronal hole, and any geomagnetic storms it creates, are more vivid auroras. Those are something everyone can appreciate and marvel at. And you don't need an x-ray satellite to see them.
The post A Dark Region Is Growing Eerily On The Sun’s Surface appeared first on Universe Today.
Welcome back to Constellation Friday! Today, in honor of our dear friend and contributor, Tammy Plotner, we examine the Bootes constellation. Enjoy! In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of the then-known 48 constellations. Until the development of modern astronomy, his treatise (known as the Almagest) would serve as the authoritative source of astronomy. This list has since come to be expanded to include the 88 constellation that are recognized by the International Astronomical Union (IAU) today. The constellation Boötes (pronounced Bu-Oh-Tays) is one of these constellations, and was also among those listed in the Almagest. It is frequently called the "Watcher of the Bear", guarding over the northern constellations of both Ursa Major and Ursa Minor (the Greater and Lesser Bears). It is bordered by Canes Venatici, Coma Berenices, Corona Borealis, Draco, Hercules, Serpens Caput, Virgo and Ursa Major. Name and Meaning: According to myth, Boötes is credited for inventing the plough, which prompted the goddess Ceres - a goddess of agriculture, grain crops, fertility and motherly love - to place him in the heavens. There are also versions where Bootes represents a form of Atlas, holding up the weight of the world as it turns on its axis (yet another of Hercules' labors). Most commonly, Boötes is taken to represent Arcas, the son of Zeus and Callisto. In this source, Arcas was brought up by Callisto father, the Arcadian king Lycaon. One day, Lycaon decided to test Zeus by serving him his own son for a meal. Zeus saw through Lycaon’s intentions and transformed the king into a wolf, killed his sons, and brought Arcas back to life. Having heard of her husband’s infidelity, Zeus’ wife Hera transformed Callisto into a bear. For years, she roamed the woods until she met her son, who was now grown up. Arcas didn’t recognize his mother and began to chase her. To avoid a tragic end, Zeus intervened by placing them both in the sky, where Callisto became Ursa Major (aka. The Big Dipper, or "Great Bear") and Arcas became Boötes. In another story, Boötes is taken to represent Icarius, a grape grower who was given the secret of wine-making by Dionysus. Icarius used this to create a wonderful wine that he shared with all his neighbors. After overindulging, they woke up the next day with terrible hangovers and believed Icarius had tried to poison them. They killed him in his sleep, and a saddened Dionysus placed his friend among the stars. Notable Features: Bootes contains the third brightest star in the night sky - Arcturus (aka. alpha Boötis) - whose Greek name "Arktos" also means "bear", and is associated with all things northern (including the aurora). Arcturus is quite important, being a type K1.5 IIIpe red giant star. The letters "pe" stand for "peculiar emission," which indicates the spectrum of the star is unusual and full of emission lines. This is not uncommon in red giants, but Arcturus is particularly strong. Arcturus is about 110 times more luminous than our nearest star, but the total power output is about 180 times that of the Sun (when infrared radiation is considered). Arcturus is also notable for its high proper motion, larger than any first magnitude star in the stellar neighborhood other than Alpha Centauri. It is now almost at its closest and is moving rapidly (122 km/s) relative to the Solar System. Arcturus is also thought to be an old disk star, and appears to be moving with a group of 52 others of its type. Its mass is hard to determine exactly, but it may have the same mass as Sol, or perhaps 1.5 times as much. Arcturus may also be older than the Sun, and much like what the Sun will be in its Red Giant Phase. Arcturus achieved fame when its light was used to open the 1933 Chicago World's Fair. The star was chosen because it was thought that light from the star had started its journey at about the same time of the previous Chicago World's Fair (1893). Technically the star is 36.7 light years away, so the light would have started its journey in 1896. Arcturus' light was still focused onto a cell that powered the switch for the lights that eventually shined so bright that Arcturus was no longer visible. Arcturus, along with its neighboring stars, also form the curious "Colonial Viper" formation, a triangular asterism invented by dedicated SkyWatcher, Ed Murray. It is so-named because it resembles a Colonial Viper being launched from a tube on the TV series Battlestar Galactica. The "Launch Tube" is formed by the intersection of Arcturus, Alphekka (Alpha Corona Borealis) and Gamma Bootis, while Izar (Epsilon Bootes) is the Viper. Other notable stars include Nekkar (Beta Boötis), a yellow G-type giant that is 219 light years from Earth. It is a flare star, which is a type of variable star that shows dramatic increases in luminosity for a few minutes. The name Nekkar derives from the Arabic word for “cattle driver". Then there's Seginus (Gamma Boötis), a Delta-Scuti type variable star that is approximately 85 light years from Earth. It shows variations in its brightness due to both radial and non-radial pulsations on its surface. Izar (Epislon Boötis) is a binary star located approximately 300 light years away which consists of a bright orange giant and a smaller and fainter main sequence star. Epsilon Boötis is also sometimes knows as Pulcherrima, which means “the lovieliest” in Latin. The name Izar comes from the Arabic word for “veil.” The star’s other traditional names are Mirak (“the loins” in Arabic) and Mizar.
Muphrid (Eta Boötis) is a spectroscopic binary star that is 37 light years from Earth and close to Arcturus in the sky. The star’s traditional name is Muphrid, derived from the Arabic phrase for “the single one of the lancer.” It belongs to the spectral class G0 IV and has a significant excess of elements heavier than hydrogen.
Boötes is also home to many Deep Sky Objects. This includes the Boötes void (aka. the Great Void, the Supervoid). This sphere-shaped region of the sky is almost 250 million light years in diameter and contains 60 galaxies. The void was originally discovered by Robert P. Kirshner - a Harvard College Professor of Astronomy - in 1981, as part of a survey of galactic redshifts.Then there is the Boötes Dwarf Galaxy (Boötes I), a dwarf spheroidal galaxy located approximately 197,000 light years from Earth that measures about 720 light years across. It was only discovered in 2006, owing to the fact that it is one of the faintest galaxies known (with an absolute magnitude of -5.8 and apparent magnitude of 13.1). Boötes I orbits the Milky Way and is believed to be tidally disrupted by its gravity, as evidenced by its shape. And there's also NGC 5466, a globular cluster approximately 51,800 light years from Earth and 52,800 light years from the Galactic center. The cluster was first discovered by the German-born British astronomer William Herschel in 1784. It is believed that this cluster is the source of a star stream called the 45 Degree Tidal Stream, which was discovered in 2006. History of Observation: The earliest recorded mentions of the stars associated with Boötes come from ancient Babylonia, where it was listed as SHU.PA. These stars were apparently depicted as the god Enlil, who was the leader of the Babylonian pantheon and special patron of farmers. It is likely that this is the source of mythological representations of Bootes as "the ploughman" in Greco-Roman astronomy. The name Boötes was first used by Homer in The Odyssey as a celestial reference point for navigation. The name literally means "ox-driver" or "herdsman", and the ancient Greeks saw the asterism now called the "Big Dipper" or "Plough" as a cart with oxen. His dogs, Chara and Asterion, were represented by the constellation of Canes Venatici (the Hunting Dogs) who drove the oxen on and kept the wheels of the sky turning. In traditional Chinese astronomy, many of the stars in Boötes were associated with different Chinese constellations. Arcturus was one of the most prominent, variously designated as the celestial king's throne (Tian Wang) or the Blue Dragon's horn (Daijiao). Arcturus was also very important in Chinese celestial mythology because it is the brightest star in the northern sky, and marked the beginning of the lunar calendar. Flanking Daijiao were the constellations of Yousheti on the right and Zuosheti on the left, which represented the companions that orchestrated the seasons. Dixi, the Emperor's ceremonial banquet mat, was north of Arcturus. Another northern constellation was Qigong, the Seven Dukes, which was mostly across the Boötes-Hercules border. The other Chinese constellations made up of the stars of Boötes existed in the modern constellation's north. These are all representations of weapons - Tianqiang, the spear; Genghe, variously representing a lance or shield; Xuange, the halberd; and Zhaoyao, either the sword or the spear. Finding Bootes: Bootes can be found south of Ursa Major, just off the handle of the Big Dipper. Because the Big Dipper is easy for most observers to find, the handle is used to point to other important stars. Bootes' brightest star, Arcturus, is also part of a mnemonic device used to orient people, which goes: "Arc to Arcturus, speed on to Spica." This means you follow the curve in the Dipper's handle away from Ursa Major until you run into Arcturus. The other star - Spica - is part of the neighboring Virgo constellation. For those using binoculars, check out Tau Bootis, a yellow-white dwarf approximately 51 light-years from Earth. It is a binary star system, with the secondary star being a red dwarf. In 1999, an extrasolar planet was confirmed to be orbiting the primary star by a team of astronomers led by Geoff Marcy and R. Paul Butler. Maybe you'd like to look at long term variable star R Boötis? It ranges from 6.2 to 13.1 every 223.4 days. For those using telescopes, there are plenty of excellent binary star systems to be seen. Pi Boötis is located approximately 317 light years from our solar system and the primary component, P¹ Boötis, is a blue-white B-type main sequence dwarf with an apparent magnitude of +4.49. It's companion, P² Boötis, is a white A-type main sequence dwarf with an apparent magnitude of +5.88. Now try looking at Xi Boötis, a binary star system which lies 21.8 light years away. The primary star, Xi Boötis A, is a BY Draconis variable, yellow G-type main sequence dwarf with an apparent magnitude that varies from +4.52 to +4.67. with a period just over 10 days long. Small velocity changes in the orbit of the companion star, Xi Boötis B - an orange K-type main sequence dwarf - indicate the presence of a small companion with less than nine times the mass of Jupiter. The AB binary can be resolved even through smaller telescopes. The primary star (A) has been identified as a candidate for possessing a Kuiper-like belt, based on infrared observations. The estimated minimum mass of this dust disk is 2.4 times the mass of the Earth's Moon. Then there's the triple system, Mu Boötis. The primary component, Mu¹ Boötis, is a yellow-white F-type sub giant with an apparent magnitude of +4.31. Separated from the primary by 108 arc seconds is the binary star Mu² Boötis, which has a combined spectral type of G1V and a combined brightness of +6.51 magnitudes. The components of Mu² Boötis have apparent magnitudes of +7.2 and +7.8 and are separated by 2.2 arc seconds. They complete one orbit about their common center of mass every 260 years. How about colorful yellow and blue Kappa Boötis? Kappa2 Boötis is classified as a Delta Scuti type variable star and its brightness varies from magnitude +4.50 to +4.58 with a period of 1.83 hours. The companion star, Kappa¹ Boötis, has magnitude +6.58 and spectral class F1V. For deep sky observers with large telescopes, try checking out the globular cluster NGC 5466, which is about a fist's width north of Arcturus. This class XII, 9th magnitude globular was discovered in 1784 by Sir William Herschel and presents an nice challenge for experienced stargazers and amateur astronomers. Or try compact spiral galaxy NGC 5248. It's about a fist width south of Arcturus and about a finger width southwest. It's part of the Virgo cluster of galaxies and could be as far as 50 million light years away. It's another great grand design spiral which shows spiral galaxy structure when viewed in long exposure photographs. You can mark it on your list as Caldwell 45. But if you'd just like to have some fun, then why not try picking out the aforementioned "Colonial Viper and Launch Tube" asterism. If you're a longstanding Battlestar Galactica fan, then you'll recognize this ultra-cool spaceship as it sits in its triangular shaped launch tube. To find it, just draw a line between Arcturus, Alphekka (Alpha Corona Borealis) and Gamma Bootis which make up the "Launch Tube", while Izar (Epsilon Bootes) is the Viper. We have written many interesting articles about the constellation here at Universe Today. Here is What Are The Constellations?, What Is The Zodiac?, and Zodiac Signs And Their Dates. Be sure to check out The Messier Catalog while you’re at it! For more information, check out the IAUs list of Constellations, and the Students for the Exploration and Development of Space page on Aries and Constellation Families.
An international trio of astronauts and cosmonauts representing the United States, Russia and Japan blasted off in the early morning Kazakh hours today, July 7, for a new mission of science and discovery on the International Space Station (ISS). The three person crew of two men and one woman launched flawlessly into picture perfect skies from the Baikonur Cosmodrome in Kazakhstan at 9:36 p.m. EDT Wednesday, July 6 (7:36 a.m. Baikonur time, July 7), and in a brand new version of the Russian Soyuz capsule that has been significantly upgraded and modified. The launch of the Soyuz MS-01 spacecraft was carried live on NASA TV starting approximately an hour before the usual on time liftoff from Baikonur. The three stage Soyuz booster generates 930,000 pounds of liftoff thrust. The trio comprises Kate Rubins of NASA, Soyuz Commander Anatoly Ivanishin of the Russian space agency Roscosmos and Takuya Onishi of the Japan Aerospace Exploration Agency on the Expedition 48/49 mission. They safely reached orbit at about 9:46 p.m. after the eight minute climb delivered them to the preliminary orbit of 143 x 118 mi. The Soyuz separated from the third stage and the solar arrays deployed as planned. NASA’s Kate Rubins was strapped into the left seat, Ivanishin in the center and Onishi on the right. And precisely because it’s a heavily modified Soyuz, they will take the slow road to the ISS. The crew will spend the next two days and 34 Earth orbits inside in order to fully check out and test the upgraded Soyuz spacecraft systems. That’s in contrast to missions in recent years that took a vastly sped up 4 orbit 6 hour route to the space station. Three carefully choreographed orbital adjustment burns will raise the orbit and propel the crew to the to ISS over next 2 days. They expect to rendezvous and dock at the space station’s Russian Rassvet module at 12:12 a.m. EDT Saturday, July 9. After conducting leak and safety check they expect to open the hatch to the ISS at about 2:50 a.m. Saturday, July 9. You can watch all the hatch opening action live on NASA TV with coverage starting at 2:30 a.m. They will spend about four months at the orbiting lab complex conducting more than 250 science investigations in fields such as biology, Earth science, human research, physical sciences, and technology development. With the arrival of Rubins, Ivanishin and Onishi, the station is beefed up to its normal six person crew complement. Rubins is on her rookie space mission. She holds a bachelor’s degree in molecular biology and a doctorate in cancer biology which will be a big focus of her space station research activities. The new trio will join Expedition 48 Commander Jeff Williams of NASA and Flight Engineers Oleg Skripochka and Alexey Ovchinin of Roscosmos. The Expedition 48 crew members will spend four months contributing to more than 250 experiments in fields such as biology, Earth science, human research, physical sciences and technology development. “The approximately 250 research investigations and technology demonstrations - not possible on Earth - will advance scientific knowledge of Earth, space, physical, and biological sciences. Science conducted on the space station continues to yield benefits for humanity and will enable future long-duration human and robotic exploration into deep space, including the agency’s Journey to Mars,” says NASA. Multiple unmanned cargo ships carrying tons of essential supplies and science experiments are also scheduled to arrive from Russia, the US and Japan over the next few months. A SpaceX Dragon could launch as soon as July 18 and an Orbital ATK Cygnus could follow in August. The Dragon CRS-9 mission is slated to deliver the station’s first International docking adapter (IDA) to accommodate the future arrival of U.S. commercial crew spacecraft, including the Boeing built Starliner and SpaceX built Crew Dragon. A Japanese HTV cargo craft will carry lithium ion batteries to replace the nickel-hydrogen batteries currently used on station to store electrical energy generated by the station’s huge rotating solar arrays. Two Russian Progress craft with many tons of supplies are also scheduled to arrive. Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news. Ken Kremer
The post International Trio from US, Russia and Japan Launches to Space Station on Newly Upgraded Soyuz appeared first on Universe Today.
Saturn's largest moon Titan is a truly fascinating place. Aside from Earth, it is the only place in the Solar System where rainfall occurs and there are active exchanges between liquids on the surface and fog in the atmosphere - albeit with methane instead of water. It's atmospheric pressure is also comparable to Earth's, and it is the only other body in the Solar System that has a dense atmosphere that is nitrogen-rich. For some time, astronomers and planetary scientists have speculated that Titan might also have the prebiotic conditions necessary for life. Others, meanwhile, have argued that the absence of water on the surface rules out the possibility of life existing there. But according to a recent study produced by a research team from Cornell University, the conditions on Titan's surface might support the formation of life without the need for water. When it comes to searching for life beyond Earth, scientists focus on targets that possess the necessary ingredients for life as we know it - i.e. heat, a viable atmosphere, and water. This is essentially the "low-hanging fruit" approach, where we search for conditions resembling those here on Earth. Titan - which is very cold, quite distant from our Sun, and has a thick, hazy atmosphere - does not seem like a viable candidate, given these criteria. However, according to the Cornell research team - which is led by Dr. Martin Rahm - Titan presents an opportunity to see how life could emerge under different conditions, one which are much colder than Earth and don't involve water. Their study - titled "Polymorphism and electronic structure of polyimine and its potential significance for prebiotic chemistry on Titan" - appeared recently in the Proceedings of the National Academy of Sciences (PNAS). In it, Rahm and his colleagues examined the role that hydrogen cyanide, which is believed to be central to the origin of life question, may play in Titan's atmosphere. Previous experiments have shown that hydrogen cyanide (HCN) molecules can link together to form polyimine, a polymer that can serve as a precursor to amino acids and nucleic acids (the basis for protein cells and DNA). Previous surveys have also shown that hydrogen cyanide is the most abundant hydrogen-containing molecule in Titan's atmosphere. As Professor Lunine - the David C. Duncan Professor in the Physical Sciences and Director of the Cornell Center for Astrophysics and Planetary Science and co-author of the study - told Universe Today via email: "Organic molecules, liquid lakes and seas (but of methane, not water) and some amount of solar energy reaches the surface. So this suggests the possibility of an environment that might host an exotic form of life." Using quantum mechanical calculations, the Cornell team showed that polyimine has electronic and structural properties that could facilitate prebiotic chemistry under very cold conditions. These involve the ability to absorb a wide spectrum of light, which is predicted to occur in a window of relative transparency in Titan’s atmosphere. Another is the fact that polyimine has a flexible backbone, and can therefore take on many different structures (aka. polymorphs). These range from flat sheets to complex coiled structures, which are relatively close in energy. Some of these structures, according to the team, could work to accelerate prebiotic chemical reactions, or even form structures that could act as hosts for them. "Polyimine can form sheets," said Lunine, "which like clays might serve as a catalytic surface for prebiotic reactions. We also find the polyimine absorbs sunlight where Titan’s atmosphere is quite transparent, which might help to energize reactions." In short, the presence of polyimine could mean that Titan's surface gets the energy its needs to drive photochemical reactions necessary for the creation of organic life, and that it could even assist in the development of that life. But of course, no evidence has been found that polyimine has been produced on the surface of Titan, which means that these research findings are still academic at this point. However, Lunine and his team indicate that hydrogen cyanide may very well have lead to the creation of polyimine on Titan, and that it might have simply escaped detection because of Titan's murky atmosphere. They also added that future missions to Titan might be able to look for signs of the polymer, as part of ongoing research into the possibility of exotic life emerging in other parts of the Solar System. "We would need an advanced payload on the surface to sample and search for polyimines," answered Lunine, "or possibly by a next generation spectrometer from orbit. Both of these are “beyond Cassini”, that is, the next generation of missions." Perhaps when Juno is finished surveying Jupiter's atmosphere in two years time, NASA might consider retasking it for a flyby of Titan? After all, Juno was specifically designed to peer beneath a veil of thick clouds. They don't come much thicker than on Titan! Further Reading: PNAS
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