33 upvotes, 1 direct replies (showing 1)
View submission: Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science
A planet is *defined* in part based on size. So *by definition* you can't have a planet that fits in your hand. However, that doesn't say anything about what is physically possible. There are countless objects in space that are the size of an orange. Many, for example, in the asteroid belt. But to be a planet an object must:
1. Orbit a star
2. Have sufficient mass for it's own gravitational forces to cause it to be spherical
3. Have sufficient mass that it's gravity clears it's orbit of other objects as large as it
I suppose a small black hole could meet each of these definitions. But otherwise, nothing that could fit in the palm of your hand would.
Comment by joshstew85 at 26/04/2023 at 19:09 UTC
2 upvotes, 2 direct replies
What is the radius of a solar mass black hole? And how fast does a hand-sized BH evaporate?