What Shape is a Star?

Nigel Goes to Space Join Nigel as he takes you on his journey to the stars and beyond! Subscribe – http://goo.gl/wpc2Q1 Nigel is an internationally acclaimed science populariser and author, specialising in astronomy and space. In this video he responds to a question about Stars from Stevo Canuck. How big are stars and what shape are they? Stars are luminous masses of plasma held together by their own gravity and vary widely in size. Some stars are huge and can be millions, or even billions, of kilometres across. When it comes to shape most of them are spherical just like our Sun, the nearest star to Earth. The reason being that they are composed of gas and so gravity pulls it in from all directions equally, ending up with a sphere. However, not all stars are spherical, like tangerine-shaped “Regulus” in the constellation of Leo, or egg-shaped “Spica” in the constellation of Virgo, or the pear-shaped “Cygnus X-1” orbiting around a black hole.