Earth As an Extrasolar Planet 83
sciencehabit writes "Astronomers have a theory that they can detect whether a planet light years away will be habitable by just looking at how its sun is reflected in its atmosphere. To test the idea, they pretended that they were observing Earth from a distant object — in this case, the moon. And sure enough, they picked up critical components for life in Earth's atmosphere: ozone, oxygen, sodium, and nitrogen."
Only works on eclipsed light. (Score:5, Interesting)
This technique only works on light that passes through the planet's atmosphere. In this case, during a lunar eclipse, they pointing a telescope at the part of the moon that was reflecting the light that had traveled through the Earth's atmosphere. They found that the moon had absorption lines resulting from interactions with Earth's atmosphere.
The technique would work if the Earth occulted the Sun from Cassini's viewpoint, but such occultations are rare.
Not new at all (Score:3, Interesting)
This is spectroscopy. They've been doing it for years, and it is the reason we know the chemical composition of everything from stars to planets to gas clouds. It's a fundamental tool of astronomy. The only novelty re: extrasolar planets is the resolution required, but even that isn't new, afaik.
The article quotes the boffin as saying
"The surprise was that we succeeded with extremely sparse observations under relatively bad weather conditions," Vidal-Madjar says. "But seeing how easily oxygen was seen strongly argues in favor of high-spectral-resolution searches [of Earthlike extrasolar planets]."
So it seems that the news here is that it's easier than expected to measure oxygen.
Re:Proving What (Score:1, Interesting)
uh, you do realize they were looking at the light reflected off the moon that was "coming" from earth ( light comes from sun to earth, bounces off, hits moon, and then they measured it, simulating a large distance since the moon is not super reflective (and neither is the earth)).
Earth is heaven... (Score:2, Interesting)
Now if only people, including Scientists of all fields, would realize that Heaven already exists and anyone that is alive is living in it. It is called planet EARTH.
No other place in the known universe has such a perfectly tuned atmosphere, able to support intelligent life. Let alone any type of life. Below is a list of traits the Earth has, which are rare, yet essential for life to spawn and be sustained.
1) A large moon to make stable the earths rotation (seasons), make oceans slosh which is said to have helped stir up the primordial soup to create chemical life.
2) A magnetosphere. Most planets/moons do not have one. Without one the atmosphere would blow away due to solar wind from the sun. Mars as an example.
3) In the goldie locks zone. Only Earth and Mars are known to exist in one, keeping water as a liquid. Not too close or far from the sun.
4) Orbiting a fairly stable Star called the SUN. Most stars are too large and burn out too fast.
5) Calm solar system, with very few cosmic impacts from comets/asteroids, allowing life to evolve and thrive in time for us to create anti-asteroid technology.
6) Earth is not too large or too small. If too small will cool down too fast and loss it's molten core and hence Magnetic Field. Example is Mars.
7) Jupiter did not ignite into a star. (Did not have enough mass) Yet, jupiter is large enough to vacuum up many objects that could have hit the Earth and killed us.
8) Large amounts of H20, carbons, Nitrogen, Iron, etc. Life needs a nice mix of elements to create an Atmosphere and life. Missing a key element and life would not be.
9) Solar system not too close to other stars/clusters to avoid Super Nova's and other hazardous stars which could kill us all.
10) Pure chance that anything else I missed that Earth has going for it to allow life to Evolve and invent technology to allow Internet and myself to type to YOU.
Now, you tell me if Earth is not a Heaven? Tell me that all of these things are not extremely good things to have happened to Earth and whether or not you think we are damn lucky yo even be alive. If not, you need to seriously consider looking into science more and learning about all the amazing things the Earth has going for it to allow you to exist at all.
We are all in Heaven as far as I am concerned. It was in front of our face the whole time, if one only puts down the ego and learns about these things.
Re:Proving What (Score:3, Interesting)
It looks like they focused on only measuring certain atmospheric things, but this proves nothing as far as extrasolar planets go.
Free oxygen on any planet tells you that something is making oxygen. In our case it is the plants which we treat so badly: turning them into newspapers, etc.
The issue is burning down large areas of rain forest to get more short-term farmland, which uses up oxygen as well as permanently destroys the source for oxygen. The newspaper is not so relevant, since it is partially recycled and partially grown for the purpose.
Re:Only works on eclipsed light. (Score:3, Interesting)
You know, someone asks this in almost every thread where the search for extra terrestrial life comes up.
The reality of it is, we don't know anything about what a hypothetical silicon-based life-form would look like, or what kind of environment it would need.
Since we know nothing about this life-form, how do you propose we look for this? The simple answer is, we can't because we don't know what to look for.
When you don't have any actual testable hypotheses, it's simply not possible to conduct science. What you're describing is essentially science fiction since you start with the position that there must be silicon-based life and we should be looking for it.
Methinks you've watched too much Star Trek.
Looking for life that is similar to ours, we can at least say "well there is life on Earth which could live under those circumstances, so maybe there's something there". The whole point is to narrow the search, not needless widen it to conditions that, at present, represent nothing more than mere conjecture.
In short, searching for silicon-based life is currently futile and a waste of resources.