There are a septillion stars in the observable universe. That’s a 1 followed by 24 zeros. If only 1 in a trillion stars has a planet with life, that would mean there are a trillion planets with life.
[Universe Today] According to astronomers, there are probably more than 170 billion galaxies in the observable Universe, stretching out into a region of space 13.8 billion light-years away from us in all directions.
And so, if you multiply the number of stars in our galaxy by the number of galaxies in the Universe, you get approximately [10 to the 24th power] stars. That’s a 1 followed by twenty-four zeros. That’s a septillion stars.
But there could be more than that. It’s been calculated that the observable Universe is a bubble of space 47 billion years in all directions.
It defines the amount of the Universe that we can see, because that’s how long light has taken to reach us since the Big Bang.
This is a minimum value, the Universe could be much bigger – it’s just that we can’t ever detect those stars because they’re outside the observable Universe. It’s even possible that the Universe is infinite, stretching on forever, with an infinite amount of stars. So add a couple more zeros. Maybe an infinite number of zeros.
That’s a lot of stars in the Universe.