How long does it take for a large cloud of gas to condense and form a star? How long does it take the debris from a star to condense and become part of a new solar system? How long ago did the first stars form? What types of stars were included in the earliest population of stars?
hmm, 1. 10 - 1000 stars can be formed from a cloud, and they probably vary widely in the time they take to form. Supernovae in the “neighborhood” can speed up the formation of stars. so there is no real answer, but to ballpark it, I would say ~10^9 years. 2. I would guess that when nuclear fusion starts in the star's core (it starts to shine) the solar wind would stop more gasses from falling in, and those gasses would shortly form into planets. (its really hard to put time frames on this stuff, perhaps there is someone here more qualified that can put more accurate times on it.) 3. the first generations of stars started to form about a billion years after the big bang. so about 13 billion years ago. 4. the first types of stars (Population III) were, on average, more massive. with only the light elements from the big bang, stars could get several hundred times the mass of our sun. however, some believe that stars could not get larger than about 100 times the mass of the sun. the jury is still out on that one.
Let's face it. There are some things we just dont know. And then there are thing we thought we knew, and then we find out they just were'nt so. I refer to the thread 3 x andromeda. REGARDS APOLO