Question: How were the stars made

Mark Kennedy answered on 17 Nov 2016:

Stars are made when very, very large clouds of hydrogen collapse down into small spheres. This process takes millions of years to complete, and initially, the hydrogen in the clouds are is very cool.

But as the hydrogen cloud contracts, it heats up until, when it’s hot enough, it begins to fuse. The energy released from this fusion helps support the cloud from further collapse.

Here’s an image of the most famous cloud of hydrogen that is currently forming stars : Those pillars are called “The Pillars of Creation”.

I wrote a much more detailed blog post about forming stars, which you can read here if you’d like: https://letstalkphysics.wordpress.com/2013/02/04/the-pillars-of-creation/