NASA Cosmic Census: 50 Billion Planets in Milky Way

If you haven’t heard, the Milky Way Galaxy is kind of large. In fact, it’s 100,000-by-1,000 lightyears in size. While this is certainly not a new development, we have had absolutely no idea about how many planets exist within our galaxy.

We do now.

NASA scientists working with the Kepler telescope have extrapolated the numbers from results at the two-year mark of a three-and-a-half year mission. Those findings? That there was some fifty billion planets in the Milky Way. Of those 50,000,000,000 planets, it’s believed that five hundred million of them exist within the “Goldilocks zone,” which is the happy medium an orbit can exist in that is neither too hot or too cold to support life.

The 50bn number is calculated by figuring that 50% of stars have planets. Of that 50%, 1-in-200 has planets that fit in the “Goldilocks zone.” These numbers hover at the low end of the spectrum since it’s assumed that many of these stars have multiple planets.

It’s important to remember that these numbers are estimates. The hard numbers are much less impressive: 1,235 candidate planets with 54 falling in the “Goldilocks zone.”

So, for those who wonder if intelligent life exists outside our planet, you could have up to five-hundred million chances to find out. That’s just staying within our own galaxy — let’s not forget that there are believed to be some 100 billion galaxies in our universe.


About Mohit


  1. You need to fix the first paragraph in this article. I think that you meant to say, “in the galaxy” and not “in the solar system.”

  2. Do you ever read what you’ve written? Really, I had no idea the galaxy was by implication a rectangle 100000 x 1000 ly. I thought it was a flatten pancake, 100000 ly “diameter” and a few 1000’s of ly thick. Quite different!!! Also, don’t you mean plants in the galaxy, rather than Solar System. I though we had a pretty good idea that there are 8 planets in our SS. Read your stuff!!!!


  3. @ R:
    Do you ever read what you�ve written? don�t you mean planets in the galaxy…Read your stuff!!!!

  4. @Mohamed Qasem
    That’s what happens when you’re working on two hours of sleep — thanks for catching that, it’s been amended.

    Never forget Pluto, man.

    Never forget!

  5. Wish Carl Sagan was alive to witness the Kepler mission…

    @James Walker
    It is official, Pluto is not a planet.

  6. @Dean
    T’was sarcasm, good sir. T’was sarcasm. :p

  7. Only time will tell if Tyche is really one of them or not….

  8. Seeing as over 80% of the Galaxy is just too violent and unstable for life to even develop you can take another 80% off that figure, then you need a stable soalr system take off another 80% etc, etc, etc.

    There is only us.

Leave a Reply

Your email address will not be published. Required fields are marked *