Podcaster: Morgan Rehnberg
Link : http://cosmicchatter.org
Description: Description: In this episode of the Monthly News Roundup, we land on one comet while early observations come in from another. A giant spot lurks on the surface of the Sun and tragedy strikes in spaceflight
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 December 30th, 2014. I’m Morgan Rehnberg, and this is the Monthly News Roundup. This episode was produced by Cosmic Chatter and recorded December 26th from York, Pennsylvania.
Our top story this month is the exciting detection of methane on the surface of Mars. It took the Mars Science Laboratory Curiosity more than two years on the Martian surface to confirm this discovery, but the results are worth the wait. Not only did Curiosity observe methane on the Red Planet, it observed the amount of it varying.
Methane, composed of one carbon atom and four hydrogen atoms, is one of the most common molecules in the Universe. So why is this discovery such a big deal? Because it’s so simple, methane is extremely light, weighing in at just half the mass of molecular oxygen. This means that it can easily overcome the weak Martian gravity and escape to space in just a few hundred years. So if we’re seeing methane today, four and a half billion years into the solar system’s history, something must be generating it today! On Earth, by far the dominant source of methane gas is living organisms, so could this finally be scientists’ long-sought evidence of alien life? Not so fast.
Although life produces most of the methane found on Earth, it’s not the only way to get the gas. A chemical reaction known as serpentinization can also do the trick, provided it occurs in a carbon-dioxide-rich environment. When water and carbon dioxide combine with a type of rock known as olivine underneath the surface, methane is one of the resulting byproducts. Carbon dioxide is the dominant gas at Mars and olivine is one of the most common rock types in the solar system, so it’s only the presence of sufficient water that we can really call into question. As evidence piles up for a Mars permeated by water, serpentinization seems more and more likely to be the source of martian methane.
But that doesn’t mean we can close the book on this topic. Curiosity detected about half as much methane as scientists expected to find, suggesting that we don’t yet fully understand the internal composition of Mars. But, even more strikingly, every few months the amount detected would suddenly spike, reaching more than ten times the baseline level. Then, in short order, it would drift back down. If it takes a few hundred years for methane to escape the atmosphere, how could this be possible? Herein lies the really exciting part. Curiosity is probably really close to the source and the monthly variation is the time it takes for the nearby wave of gas to dissipate into the global atmosphere.
But why these regular pulses in the first place? That’s a question that is still puzzling scientists. Fortunately, Curiosity isn’t going anywhere and will continue to study this remarkable phenomenon for years to come.
Early in December, human spaceflight in the United States took a big step forward with the successful test launch of the Orion crew capsule. It lifted off aboard a United Launch Alliance Delta IV Heavy rocket on December 5th for four hours of maneuvers in space. Over the course of two orbits about the Earth, Orion reached an altitude of nearly six thousands kilometers. That’s farther than any spacecraft designed for humans has ventured since Apollo 17 returned from the Moon in 1972.
We’ve talked a lot this year about private companies’ space capsules, like Boeing’s CST-100 or SpaceX’s Dragon. NASA is spending billions of dollars to fund the development of these ships, so why is it also building a crew capsule itself? Ultimately, Orion is designed to perform more demanding tasks than these other vessels. While Boeing and SpaceX have contracts to ferry astronauts to the International Space Station a few hundred kilometers above our heads, NASA envisions Orion as the foundation of a system to carry explorers back to the Moon, to an asteroid, and beyond.
In this test, flight controllers demonstrated that Orion is capable of maneuvering in the vacuum of space. More importantly, they showed that the heat shield could withstand the incredible temperatures experienced during atmospheric re-entry. As it slowed down from speeds as high as 32,000 kilometers per hour, the hull experienced temperatures that approached half that of the surface of the Sun.
There’s another difference, though, between Orion and the commercial crew capsules: its schedule. While Boeing and SpaceX hope to be dropping off astronauts at the ISS within two years, Orion won’t even be on the launchpad for another test until the end of 2018 and won’t carry humans until at least 2021. What’s the holdup? Orion is designed to work in tandem with the Space Launch System, NASA’s next generation heavy-lift rocket. Only SLS will offer enough power to lift Orion beyond Earth orbit and on to its interplanetary destinations. But, the rocket is still in development and will need to be tested and certified as safe for crewed flight before any astronauts can climb aboard.
So, for now, it’s still robotic explorers only if we want to venture out into the solar system.
While NASA continues to invest in becoming independent of Russia for transportation to space, Russia itself is considering an even more isolationist stance. This month Roscosmos, the Russian space agency, announced that they were considering a plan that would involve them leaving the consortium of nations supporting the International Space Station and developing their own base in space.
These threats come as economic sanctions, imposed by many Western nations over the conflict in Ukraine, take an increasingly dire toll on the Russian economy. Russian leaders rightly see human space exploration as a realm in which their nation is an indispensable partner. What they must surely also know, however, is that no nation is truly prepared to go it on their own in space.
Both the United States and the Soviet Union have gone that route before, with America building Skylab in the 1970s and Russia operating the Soviet-launched Mir from 1986 to 2001. But today’s economic situation is far different than that which supported space exploration during the Cold War, and the ISS’s more than 100-billion-dollar cost would be unpalatable to even the richest nations.
A solo effort would be particularly challenging for Russia, as increased sanctions restrict the flow of materials and technology needed for high-tech development. Roscosmos would essentially need to build the entire project internally, and recent failures in robotic exploration suggest that they lack the capability to do so reliably.
Russia isn’t the only nation in this situation. China has also been isolated by the international community and is also developing their own space station. An early test module, Tiangong-1, has been in orbit since 2011 and, unlike Russia, China’s economy is growing robustly. They, too, however, would be better off if cooperation where possible. Perhaps, like in the past, co-existence in space can foster better relations here on Earth.
Finally this month, a look back on the past year. Like any year, 2014 was one marked by successes and failures. It saw the start of new ventures with the launch of Hayabusa 2, the arrival at Mars of MAVEN and the Mars Orbiter Mission, and the groundbreaking on the Thirty Meter Telescope. It saw access to space grow as never before with the awarding by NASA of commercial crew contracts to Boeing and SpaceX. And it saw the success of an audacious mission when the tiny Philae lander touched down on the surface of a comet.
But 2014 also reminded us of the dangers of exploring space. When an Orbital Sciences Antares rocket blew up on the launchpad, the viability of commercial space exploration was set back just a bit. And when the VSS Enterprise broke apart over the Mojave Desert, the world experienced its first loss of life from spaceflight in more than a decade.
I could go on and on, and that’s ultimately the point. 2014 was another year during which we were out there exploring the cosmos, a year where we overcame longstanding barriers and embarked upon new journeys. And any year about which you can say that is a pretty darn good one.
End of podcast:
365 Days of Astronomy
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