|About how many stars are in space?|
|Question Date: 2013-02-19|
There are about
stars in space, or about 10 raised to the 21
This amount is about equal to the number of
grains of sand on ALL of the beaches on planet
Earth!!! That is a lot!!
This is a fantastic question, and one that is
difficult to answer! I did some research on the
stars, click here and found some
fascinating information! Our galaxy, the Milky
Way, has approximately 100 billion stars in it,
but the Milky Way is not the only galaxy in the
There are about 10 billion galaxies in the
observable universe! The number of stars in a
galaxy varies, but assuming an average of 100
billion stars per galaxy means that there are
about 1,000,000,000,000,000,000,000 (that’s 1
billion trillion) stars in the observable
Notice that I have been saying the
observable universe. We can only observe parts
of the universe that are within 13.7 billion
light-years of Earth. This is because the big
bang occurred about 13.7 billion years ago. We
make observations about distant stars by
measuring the light that reaches Earth and
satellites that we have in space. Light from
stars farther than 13.7 billion light-years away
has not had time to reach us yet! The universe
must be much bigger than the universe that we
can observe at this time, therefore there may be
many more stars out there!
The number is probably infinite, but we can't
see them all because light travels at a finite
speed, and light has had only about 13.7 billion
years to travel. This means that we cannot see
any stars farther than about 13.7 billion light
Within 13.7 billion light years, we can see
roughly 50 billion galaxies, each of which is
composed of somewhere around 100 billion
I think the estimate is about
(a 9 followed by 21 zeros!).
Scientists estimate that there are about 1
000 000 000 000 stars in the Milky Way galaxy,
which is one of ~1 000 000 000 000 galaxies.
Although these are rough estimates, using these
numbers we might imagine there are...a lot...of
stars. The number is so large we usually write
it in a special way. The number is 1 000 000 000
000 000 000 000 000, which has 24 zeros, so we
write it as 1024.
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