Podcaster: Morgan Rehnberg
Title: Monthly News Roundup: A Busy World
Link : http://cosmicchatter.org
Private spaceflight: http://cosmicchatter.org/news/2014/9/18/two-developments-in-commercial-spaceflight-this-week
Description: Mars is getting crowded! A big announcement from NASA and an even bigger black hole. Is Earth no longer the only world with plate tectonics?
Bio: Morgan Rehnberg is a graduate student in astrophysics and planetary science at the University of Colorado – Boulder. When not studying the rings of Saturn, he develops software to help search for asteroids that might hit the Earth. He blogs and podcasts about astronomy and space science at http://cosmicchatter.org.
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You’re listening to the 365 Days of Astronomy podcast for September 30th, 2014. I’m Morgan Rehnberg and this is the Monthly News Roundup. This episode was produced by Cosmic Chatter and recorded September 25th from Boulder, Colorado. It includes information about the MAVEN spacecraft, which is operated by my employer, the Laboratory for Atmospheric and Space Physics at the University of Colorado.
Our top story this month is the dramatic arrival of two spacecraft at the planet Mars. On September 21st, NASA’s MAVEN probe successfully entered Martian orbit and, just two days later, India’s Mars Orbiter Mission achieved the same result.
This is an exceptional time for Mars research. Five spacecraft, MAVEN, Mars Orbiter Mission, Mars Reconnaissance Orbiter, Mars Express, and Mars Odyssey, are now in orbit about the Red Planet. Two more, Curiosity and Opportunity, are driving around on its surface. And, a further three, Insight, EXoMars, and Mars 2020, are currently in development. Never before have we had so much capability to do science at another world.
This is an especially large moment for the nation of India as it steps out onto the main stage of space exploration. The world has launched more than forty missions towards the Red Planet in the last fifty years. Fewer than half have survived, and the Indian space agency becomes just the fourth in history to successfully deliver a payload to Mars.
So what will these missions study now that they’ve completed their voyages? For MAVEN, it’s all about the atmosphere. Long ago, we believe that Mars probably had an atmosphere quite similar to that of the Earth’s, but today the Martian air is just one percent as thick as our own. Where did it all go? That’s what MAVEN will try and find out. In addition to measuring the composition and distribution of the Red Planet’s atmosphere, the probe will simultaneously monitor the energy and particle output of the Sun. For the first time ever, MAVEN will enable us to correlate activity on the Sun with atmospheric conditions at Mars. And, when its main mission is complete, the spacecraft will become an orbiting communication satellite, relaying signals from rovers on the Martian surface back to mission control here on the Earth.
India’s Mars Orbiter is less ambitious, but that’s not surprising since they consider the mission a technology demonstration above all else. Even so, the probe packs five instruments: two for studying the planet’s atmosphere, two for capturing both visible and infrared images, and one to characterize the particles found in the space around Mars.
With a record-setting seven missions studying the Red Planet, we’re certain to learn more about Mars than ever before. But, have we gone overboard with the most popular planet? Many scientists believe that Venus, not Mars, is the planet most like our own. Yet, only one mission, the European Space Agency’s Venus Express, is studying our sister world. And two planets in the solar system, Uranus and Neptune, have never even had a single mission dedicated to them. When it comes to our siblings out there in the solar system, there’s no doubt that we’re playing favorites.
Have you ever looked up at the night sky and been in awe of the vast array of stars overhead? If you happen to be in one of the darkest places on Earth, you might be seeing about four thousand stars. More likely, a few hundred dot your view. Now imagine a truly otherworldly sight: a million stars shining above you. That’s the view you’d get from a typical planet within the ultra-compact dwarf galaxy M60-UCD1. More than 140 million stars are packed into a region of space one hundred thousand times smaller than our own Milky Way.
And, lurking at its center is an enormous supermassive black hole. Weighing in at 21 million times more massive than our own Sun, this behemoth is five times larger than the black hole found at the center of our galaxy. That’s despite the fact that this tiny dwarf has only about 1/10th of one percent as many stars as the Milky Way. Putting it all together, astronomers find that the supermassive black hole at the center of M60-UCD1 is an astonishing fifteen percent of the galaxy’s mass. Compare that to our own black hole, which weighs just 1/100th of one percent of the mass of the Milky Way.
This discovery adds a new twist to the long running chicken-and-egg problem astronomers face when thinking about supermassive black holes. Do galaxies form around supermassive black holes that already exist, or do these enormous singularities grow from within the galaxy itself? And, if that latter idea is true, how could a galaxy grow a black hole to be such a large fraction of its own mass? One idea is that M60-UCD1 was once ten times larger than it is today, but a close encounter with the gigantic M60 galaxy itself stripped the dwarf of all but its dense core.
That explanation could also hint at the ultimate fate of this remarkable little galaxy. Sometime in the future, M60-UCD1 could come back around for another pass of the larger M60. And, lurking at the center of that giant galaxy is a black hole of truly mind-boggling proportions: one that is more than a thousand times larger than the one at the center of the Milky Way and more than four and a half billion times more massive than our Sun. If a close encounter were to occur, it could spell the end for M60-UCD1 and its million-star night skies.
From giant black holes, let’s turn to giant contracts. NASA awarded two of them this month in what was one of the most eagerly anticipated announcements of the last few years. The contracts, totalling 6.8 billion dollars, were awarded to Boeing and SpaceX for the first-ever crew transports designed and operated by private industry. WIth anticipated launch dates in 2017, this month’s announcement puts NASA on track to free itself from dependence on Russian Soyuz crew capsules during this politically-difficult time.
SpaceX may actually have more of the public’s attention these days, with its flashy PR videos and charismatic CEO showing up all over the Internet, but it sounds as if this competition was always Boeing’s to lose. Rumors before the announcement were that NASA viewed Boeing as the “safe” option, but SpaceX as the “exciting” option. In the end, the agency chose to back more than one, offering about two thirds of the money to Boeing and the other third to SpaceX.
So, what does that cash buy NASA? The agency has guaranteed each company at least one crewed flight to the International Space Station, with the option for as many as five more. It’s a pretty nice deal for the companies, as these contracts are for services rendered only, not the spacecraft themselves. Boeing will own and operate its CST-100 and SpaceX will do the same for its Dragon. Importantly, these are not exclusive agreements, meaning that both companies can offer their services to third parties, both public and private. As with most industries, spaceflight benefits from economy of scale and NASA is sure to reap benefits from allowing private companies virtually unlimited freedom in selling their products.
This is the start of a bold new chapter in the history of space exploration. Offloading basic transportation tasks to industry will allow NASA and other public space agencies to focus on the truly big problems in exploration: how to get man and machine to worlds far away and how to do it without breaking the bank.
One of the most fascinating episodes of twentieth-century science is the development of the theory of plate tectonics. Plate tectonics is the notion that large sections of the Earth’s crust move independently of each other and that this movement is responsible for the major geographic features of our planet. For decades, all the evidence in support of this idea was staring us right in the face, but, despite the efforts of some junior scientists, the broader geologic community didn’t accept it until the 1970s. Today, plate tectonics is invoked as a mechanism for nearly every large-scale Earth process
No other planet in our solar system today appears to have plates of its own, but that doesn’t mean that there is no hope for plate tectonics out there. Back in 2005, the Cassini spacecraft dropped the Huygens probe onto the surface of Saturn’s moon Titan. With its thick atmosphere and surface oceans, Titan may be the solar system body that most closely resembles Earth today, and images from Huygens revealed some patterns on the surface that could be indicative of tectonic-type activity. And, this month, we can add another moon to our list of possibilities: Jupiter’s moon Europa.
Europa is probably best known for the vast oceans of liquid water that scientists believe exist under its surface. The moon was last studied closely by the Galileo mission, which orbited Jupiter between 1995 and 2003, and it’s from images taken then that scientists now claim to have detected evidence of plate tectonics.
As tectonics moved the surface of Europa around, some large features were ripped apart. By realigning them, researchers reassembled the history of Europa kind of like a jigsaw puzzle. This revealed regions called subduction zones near the moon’s north pole. Subduction zones are places where one plate overlaps another. The lower plate is pushed underneath the surface, where it melts and is reabsorbed into the crust. On Earth, these zones can cause volcanoes and, sure enough, a dormant ice volcano appears to lie in the same region.
Even if plate tectonics are, in fact, active on Europa, they don’t seem to work in the same way as on Earth. Here, our ocean sits above the crust and interacts with tectonic processes. The interaction between water from the oceans and material from deep within our planet produces a chemical environment conducive to life. Europa’s ocean, on the other hand, lies many kilometers below the moon’s surface and probably doesn’t interact with any of the plates above. But, even if this isn’t so encouraging for the development of life, it’s still exciting to find out how dynamic our solar system really is.
Thanks for listening to this episode of the Monthly News Roundup. For more astronomy news and commentary, visit http://cosmicchatter.org or follow @cosmic_chatter on Twiter. As always, you can contact us with your comments and corrections at firstname.lastname@example.org. See you in October!
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