Question: How does nebula form?

Ry Cutter answered on 25 Sep 2019:

Hi cailean17,

This is a big question! So, lets start with what a nebula IS!

You’ve probably seen the really pretty pictures, but I’ll link them here too:
https://www.spacetelescope.org/images/archive/category/nebulae/

Nebulae (multiple nebula) are regions in space where there is lots of gas and dust. It’s unusual to find so much ‘stuff’ in one area, and there’s usually lots of interesting physics happening in them.

There are two ways that nebulae come into existence:

The first, is the result of the death throes of a star going supernova. When a star uses up all of it’s fuel for fusion, it collapses under its own weight. This creates a runaway reaction which causes it to explode, we call that explosion a supernova. As the star erupts it throws all of its material out leaving the pattern of dust in space. What’s really cool, looking at the crab nebula, we can see the neutron star left after the explosion. Like a ghost of the star that exploded!

The second way is a lot “nicer”. As dust and gas flies through space gravitational forces will pull it in preferential directions. Eventually enough gas will be in one place that it will form a nebula. Unlike the first way which is the end of a stars life, this way is the beginnings of a new star! Over time the gas will get pulled into one spot. Eventually enough gas and dust will be in that spot that it starts to heat up and eventually starts fusing, all that gas and dust has turned into a star! Because nebula are the birthing grounds for new stars we often call them star nurseries.

Great Question!

Ryan