What kind of star is the smallest, with a typical one being only about 20 miles across?
Answers
Not that small and very far from each other!
Using our Sun (which is a fairly typical star) as an example, it is roughly a million miles across (that’s about one hundred times the diameter of the Earth)
Note, the distance from the Earth to the Sun is not to scale in the above diagram - in reality, about 100 Suns would fit between the Earth and the Sun.
And from our Sun to our nearest neighbour - Proxima Centauri, is 3.4 light years.
A light year is about 6 trillion miles, so Proxima Centauri is about 20 TRILLION MILES away. So you could fit around 6 million Suns in between!
In our part of the Galaxy (far away from the centre, about three quarters to the edge), these distances are fairly typical. However, closer in, nearer to the hub or galactic centre, the distances can be far less, possibly only a few million miles of separation.
Of course, stars can be a lot bigger AND a lot smaller than this!