Home > Astronomy > Scale of Earth, Sun, Galaxy, and Universe

On average, how many stars have planets orbiting them?

Answer 1

An impossible question to answer.

Astronomers have only recently found planets outside of our solar system; of the 715 planets they have found, 715 revolve around 305 stars, or slightly more than two planets for every star.

It is reasonable to assume that the planets we have found have another 6 or 7 planets with them revolving around that one star, since our medium-sized star has 8 full-size planets orbiting it.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Lydia Allen

An estimated 1 in 5 or 20% of Sun-like stars have planets the size of Earth orbiting within their habitable zones, where conditions could be favorable for life as we know it. The precise number of stars with planets is hard to pin down because it depends on a number of variables, including observational biases and methods of planet detection.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.