Kepler’s Universe: More Planets in Our Galaxy Than Stars

by Nancy Atkinson on February 19, 2014

Astronomers estimate that the Milky Way contains up to 400 billion stars and thanks to the Kepler mission, we can now estimate that every star in our galaxy has on average 1.6 planets in orbit around it.

This new video from our friends Tony Darnell and Scott Lewis focuses on the discoveries that the Kepler Space Telescope has made, which has opened up a whole new universe and a new way of looking at stars as potential homes for other planets. Only about 20 years ago, we didn’t know if there were any other planets around any other stars besides our own. But now we know we live in a galaxy that contains more planets than stars.

If you extrapolate that number to the rest of the Universe, it’s mind-blowing. 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 1024 stars. That’s a 1 followed by twenty-four zeros, or a septillion stars.

However, it’s been calculated that the observable Universe is a bubble of space 47 billion years in all directions… or it could be much bigger, possibly infinite. It’s just that we can’t detect those stars because they’re outside the observable Universe.

So, there’s a lot of stars out there.

As the video says, space telescopes give us “a glimpse of our humble place in the cosmic ocean.”

Kepler space telescope's field of view. Credit: NASA

Kepler space telescope’s field of view. Credit: NASA

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

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