Earth As an Extrasolar Planet

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."

Comments

Re:Why not point Cassini back at us?

[Tablizer]

Cassini is probably not designed to be sensitive to those signatures. It's built for Saturn and co. It cost a lot to add & launch extra's outside of mission objective.

Re:Narrow-minded folks

[cheesecake23]

wHo says that life needs oxygen? Even on our planet are living beings who do not need oxygen at all. Black smoker bacterias for example. Life develops according to outer circumstances. Darwin. Read it. it's just plain stupid to believe extra-terrestial life can only develop on Earth 2.

Thank God we have enlightened ACs teaching scientists how to do things! I'm sure they never considered the points you raised.

To address your point: they do NOT assume that life needs oxygen. However, the presence of significant amounts of oxygen in a planetary atmosphere is a strong indicator of life. This is because the gas is so reactive that it gets removed from the atmosphere very quickly. The only reason we have oxygen in our air is because it is continuously put there by photosynthesis.

Re:Only works on eclipsed light.

[Jarik C-Bol]

yes of course, lets worry deeply about detecting (from light years upon light years away) a form of life that has only be theorized to be possible, and if exists is most likely in an environment that is totally incompatible with ours, thus making any contact with such life forms extremely difficult at best..

or you know, we could figure out how to detect life forms similar to our own, then try and branch out from that knowledge base once we accomplish that.