Stardate 2004-04-06 First Generation of Stars

Ref: http://stardate.org/radio/program.ph...&id=2004-04-06
http://www.utexas.edu/general/stardate/sd20040406.ram

The First Stars

Many of the stars that are visible to the unaided eye are classified
as supergiants -- the most massive stars in the galaxy. They're much
bigger, heavier, hotter, and brighter than our own star, the Sun. A
couple of good examples are Rigel and Betelgeuse, the brightest stars
of Orion, which is low in the southwest in early evening.

Yet even these stars would have been puny compared to the very first
stars, which were born when the universe was quite young -- perhaps
only one or two percent of its current age.

These stars were made only of the elements produced in the Big Bang --
mostly hydrogen and helium. No other elements even existed -- no
oxygen, no carbon, no iron, no gold. All of these elements are
produced inside stars. Since no stars had yet lived, none of the
heavier elements had been made.

Without these elements, the stars grew to enormous proportions.
Computer simulations show that the heaviest stars could have been
thousands of times as massive as the Sun. By comparison, the heaviest
stars in the modern universe are no more than a couple of hundred
times the Sun's mass.

These first-generation stars probably didn't live long, though. Within
a few million years, they would have exploded. Most left behind black
holes. But a few blasted themselves to smithereens, sprinkling the
universe with the elements needed to make the second generation of
stars -- and the first generation of planets. More on that tomorrow.

Script by Damond Benningfield, Copyright 2004