Astronomers have analyzed Earthshine-- sunlight that bounces off Earth to illuminate a darkened area of the Moon-- to see if that light could reveal life on Earth, and they found it could indeed. By picking apart the light's spectrum, they could identify the signatures of gases, like oxygen, that quickly combines with other elements. Therefore, finding free oxygen in an atmosphere implies it is constantly being replenished by something. That something is life. Closer analysis of the light also hinted at various landmasses and areas of vegetation on Earth's surface.
Astronomers plan to use techniques developed to analyze Earthshine to tease apart light bounced off an exoplanet and learn more about such worlds-- hopefully finding alien life by reading the signature it leaves in the atmosphere of its home world. Another good thing is that reflected light is polarized, while direct starlight is not. So, even though the light of a star would completely overwhelm the light reflected off one of its planets, astronomers focused on polarized light can concentrate on the planet.
Wednesday, February 29, 2012
Tuesday, February 28, 2012
Lunar Cataclysm
Around four billion years ago, which would have been only shortly after it was formed, the Moon was pounded by a flurry of bodies in what scientists have dubbed the "lunar cataclysm." A new study, using data from the Lunar Reconnaissance Orbiter, finds that those cataclysmic flying rocks were not only numerous, they were also extremely energetic. Scientists interpret that increased energy as meaning the bodies were moving faster than normal.
So, why would they be moving faster during one specific period? Four billion years ago, the Solar System was still sorting itself out, settling into the system we know. Mighty Jupiter, especially, was disrupting the orbits of asteroids with its powerful gravitational field, throwing asteroids in towards the Sun. It was those asteroids that pummeled the Moon, creating some of the largest lunar basins we see today. As the giant planets established the orbits they have today, the bombardment of the inner System slowed to the occasional shot.
So, why would they be moving faster during one specific period? Four billion years ago, the Solar System was still sorting itself out, settling into the system we know. Mighty Jupiter, especially, was disrupting the orbits of asteroids with its powerful gravitational field, throwing asteroids in towards the Sun. It was those asteroids that pummeled the Moon, creating some of the largest lunar basins we see today. As the giant planets established the orbits they have today, the bombardment of the inner System slowed to the occasional shot.
The Consequences Of Cuts
As Congress tries to deal with huge federal budget deficits that project for years into the future, NASA's budget-- well less than one percent of the overall federal budget-- is seeing the space agency devour its own in an attempt to maintain at least some momentum in its space exploration efforts.
After budget cuts forced NASA to withdraw from the ExoMars program it had developed with the European Space Agency, NASA is now looking at a smaller Mars mission. To pursue that mission, however, it is gutting funding for outer planet exploration-- Jupiter, Saturn, Uranus, Neptune, and all their moons. A few of those moons are candidates to be the home of life. Finding life beyond Earth is supposed to be a main focus of NASA.
NASA says it will invite international partners to join its smaller Mars mission. The Europeans, at least, will likely decline.
After budget cuts forced NASA to withdraw from the ExoMars program it had developed with the European Space Agency, NASA is now looking at a smaller Mars mission. To pursue that mission, however, it is gutting funding for outer planet exploration-- Jupiter, Saturn, Uranus, Neptune, and all their moons. A few of those moons are candidates to be the home of life. Finding life beyond Earth is supposed to be a main focus of NASA.
NASA says it will invite international partners to join its smaller Mars mission. The Europeans, at least, will likely decline.
Monday, February 27, 2012
2011 AG5
The asteroid 2011 AG5, discovered just last year, is the new body most likely to crash into Earth in the near future. The date is February 5, 2040. Of course, since it was just found last year, the asteroid has not yet been observed through one complete orbit. Once it is, astronomers will have a better idea of just how likely a collision actually is.
At 460 feet across, 2011 AG5 is not a Doomsday rock, but, depending on where it hit, a collision could still result in a huge disaster.
At 460 feet across, 2011 AG5 is not a Doomsday rock, but, depending on where it hit, a collision could still result in a huge disaster.
Sunday, February 26, 2012
Managing Space Junk
A new NASA study suggests that de-orbiting five major pieces of space junk per year, coupled with less dramatic measures such as burning off fuel from old satellites, as well as discharging batteries that are no longer useful, could stabilize the problem of space junk in low Earth orbit at the current level for the next 200 years.
That, of course, would stabilize the situation at a relatively high risk level, but that would be preferable to letting the problem continue to develop. The key to ultimately dealing with this problem may well rest in Russia. Due to the robust space efforts over nearly six decades of the Soviet Union/Russia, the bulk of the junk is owned by Russia. Concentrating on de-orbiting American pieces would be a start, but finally dealing with the problem will require Russian cooperation.
De-orbiting large pieces of junk, such as spent rocket stages, by the way, could be, if properly structured, an early successful industry in the commercialization of space.
That, of course, would stabilize the situation at a relatively high risk level, but that would be preferable to letting the problem continue to develop. The key to ultimately dealing with this problem may well rest in Russia. Due to the robust space efforts over nearly six decades of the Soviet Union/Russia, the bulk of the junk is owned by Russia. Concentrating on de-orbiting American pieces would be a start, but finally dealing with the problem will require Russian cooperation.
De-orbiting large pieces of junk, such as spent rocket stages, by the way, could be, if properly structured, an early successful industry in the commercialization of space.
Friday, February 24, 2012
Nomad Planets
A new study indicates there may be as many as 100,000 times the number of nomad planets in our galaxy as there are stars. A nomad planet is a large body following its own path through interstellar space; it is not in orbit around any star.
Astronomers know very little about these worlds. Until recently, such worlds existed only in science fiction. Until very recently, astronomers had no way to detect them. Where they come from isn't clear. Some were ejected from solar systems, but there is evidence that too many exist for all of them to be accounted for in that way. Having said that, however, coming up with a process by which planets would form in free space, away from any stars, is a real challenge.
Once again, trying to understand the universe is forcing humans to expand our notions of what's possible.
Astronomers know very little about these worlds. Until recently, such worlds existed only in science fiction. Until very recently, astronomers had no way to detect them. Where they come from isn't clear. Some were ejected from solar systems, but there is evidence that too many exist for all of them to be accounted for in that way. Having said that, however, coming up with a process by which planets would form in free space, away from any stars, is a real challenge.
Once again, trying to understand the universe is forcing humans to expand our notions of what's possible.
Thursday, February 23, 2012
Space Elevator?
According to a report in a Japanese newspaper, Tokyo-based Obayashi Corporation is seriously pursuing building a space elevator by 2050.
A space elevator would lift people and cargo into orbit without the need of a rocket launch. Similar to using an elevator in a building, a person would step into a car on Earth's surface, for example, and the car would ride up cables into space. In the Obayashi plan, the super strong cables made of carbon nanotubes would be 60,000 miles long and attached to a counterweight in space to keep them taut. That system could deliver a payload to geosynchronous orbit, 22,000 miles out, after a week of steady climbing. The elevator could be powered by solar energy.
Obayashi suggests the biggest obstacle to be overcome to bring this project into reality may be financing it.
A space elevator would lift people and cargo into orbit without the need of a rocket launch. Similar to using an elevator in a building, a person would step into a car on Earth's surface, for example, and the car would ride up cables into space. In the Obayashi plan, the super strong cables made of carbon nanotubes would be 60,000 miles long and attached to a counterweight in space to keep them taut. That system could deliver a payload to geosynchronous orbit, 22,000 miles out, after a week of steady climbing. The elevator could be powered by solar energy.
Obayashi suggests the biggest obstacle to be overcome to bring this project into reality may be financing it.
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