Friday, March 19, 2010

Its Coming Right For Us!

It turns out that a small red-orange star called Gliese 710, currently some 69 light years away, is on a collision course with the Solar System. But before anyone panics, it won't actually collide with the Sun or any major planets, and will in fact just clip the outer edge of the Sun's Oort Cloud. And all this won't happen for another 1.5 million years or so. Check out the the full article form NEW SCIENTIST.

The brushing of the Oort Cloud is actually pretty significant. For those who may not be up on such things, the Oort Cloud is an extremely disperse 'cloud' of cometary material left over from the formation of the Solar System. It extends roughly from the outer edge of the Kuiper Belt (where we find planet-sized iceballs such as Pluto, Sedna, and Eris) at some 50 AUs out to up to two light years away from the Sun.

Such a massive object passing so close to the cloud would disturb the orbits of a great many of the comets drifting out that way, inevitably send some veering toward the inner Solar System--and Earth. So its very possible that Gliese 710 could precipitate one or more extinction events during its cosmic flyby.

But an interesting possibility no one has mentioned yet is that even while Gliese 710 mucks up the Sun's Oort cloud, the Sun will also muck up Gliese 710's Oort Cloud in turn (assuming it has one, of course. From what we understand of star/solar system formation, it should have one, but we don't know for sure). In fact, chances are the Sun, being more massive and with a more powerful gravitational influence, would likely end up drawing off more comets from Gliese's Cloud than vice-versa.

This raises an interesting possibility. Other such near-misses must have happened in the past, and each time the Sun would have drawn off comets form other stars' Oort clouds. We tend to think of all the debris like asteroids and comets in our Solar System as left over junk from the formation of the sun and planets, but what if a significant percentage of it has actually been 'stolen' from other stars during near misses? It might give a boost to panspermia theories, which theorize that life on Earth originated from space and was seeded by ancient comet impacts.

Of course we can't know for sure until there's an extensive survey of the chemical composition of various comets, and that's at least decades away. But its something to think about.

Saturday, March 6, 2010

Comet Ghosts Haunting Earth Orbit

A new type of asteroid, or at least a type that's been poorly studied before because of their difficulty to spot-- has been detected in orbits that cross Earth's own. Go HERE for the full article from New Scientist.

Basically, the scientists are guessing that these may to be the remnant cores of dead comets, having long since used up all the ice and other volatiles that made up their visible tails. They reflect less than 5%-10% of the light that strikes them. However, because they absorb so much more, they are able to be spotted much more easily in the infrared spectrum, such as in the photo above (image courtesy of NASA, btw.)

I think its a very cool discovery, considering they're like comet 'ghosts' haunting the space near Earth. As long as none of them hit us, of course.

Tuesday, March 2, 2010

600 Million Tons Of Lunar Ice

Recent data analysis from India's Chandrayaan-1 probe has confirmed the presence of water ice in craters near the Moon's poles. The full article can be found HERE on NASA's main website.

If their estimation techniques are correct, the scientists estimate there being at least 600 million metric tons of water ice in the lunar polar region. That is of course spectacularly good news for future bases, and further into the future, colonies, on Earth's natural satellite. That much ice, combined with careful recycling and management, could both provides water, oxygen, and rocket fuel for manned endeavors there for many decades.

And of course, ironically, this comes on the heels of the Obama administration killing off any prospect for returning to the Moon in the short term. We can now see much more clearly how feasible a long-term manned presence on the Moon can be, only to have the prospect of establishing such an outpost pushed out of our reach to at least until the mid-2020s. Its not that the other projects the new administration want to pursue aren't worth doing, but actually opening up a brand new world to humanity would seem to be the better choice of a long range goal, in my opinion.

Oh well. One thing I should suggest to NASA (not that i think anyone there will actually read this): as long as you're underwriting various private space endeavors and X-prize like contests, how about underwriting a sample-return mission for the lunar ice? We can learn definitively what's in it and probably how it was formed. plus the mission may just help to scout out a possible future manned landing site...