Question: How did "life" begin?

Jonathan Hunter answered on 17 Jun 2016:

This is a very interesting topic which I have studied quite a bit!
There are may theories but no one conclusive one yet.
Amino acids (things which make up proteins) can be found on asteroids and in space. There is a really famous experiment called the Urey-Miller experiment where they made amino acids by passing lightning through water, ammonia, methane and hydrogen (similar to the gases found on the early Earth). This also produced amino acids.
From then on it gets a bit hazy.
It is thought that the amino acids became life via RNA (single strand DNA) then DNA and eventually became life as we know it (bacteria) about 4.1 billion years ago.
The Earth is about 4.5 billion years old.
Another interesting theory is that life came to the Earth from another planet, as some microscopic creature can survive going through spaces (Tardigrades).
Another theory is that life began deep at the bottom of the ocean around hydrothermal vents. This is similar to the RNA/DNA theory.
There is still a lot of work going on to work out if which is true.
Personally, I like the “we are all aliens” theory!