0
votes
1answer
172 views

Validity Of the Drake Equation [closed]

The Drake Equation is designed to estimate the number of Planets possibly having intelligent life forms existing in our Galaxy. But I don't see how it's justified. As far as we know, Earth is the only ...
5
votes
1answer
3k views

How much sky do we see at any one moment?

When we look at any particular point the sky, what percentage of the celestial sphere do we see? This question arises from the notion that on average there passes one meteor per hour overhead. So ...
9
votes
2answers
310 views

Silicon-based life [closed]

My question may not be suitable here, because it's more of astrobiology. Life as we know it is carbon based. Is life based on silicon possible? What would the conditions for habitability for ...