How Do Stars Form?

Stars form within clouds of dust that are scattered around the galaxies of our Universe. In essence, a star is dust that is pulled toward a central point of gravity and, when this happens, begins to heat up. The formation of a star results in something like our own Sun which took 50 million years to turn into what it is today. And, our Sun will last another five billion years–or ten billion years in total from the formation of the Universe.

Within these clouds of dust there is a lot of turbulence. With this turbulence, knots of mass appear. This mass becomes strong enough that gas and dust collapse upon itself with gravitational pulls. When the cloud collapses, the center of the "collapsing dust" begins to heat up. This is known as a protostar. It's not quite the finished product–similar to a prototype in technology–but it is starting to resemble the finished product.

As this protostar heats up, it continues to pull more dust and gas toward it. However, not all of this dust and gas becomes part of the star. It can, in its development, lead to planets, comets, moons and other stars. it's because of the spinning of the protostar that, in the Milky Way galaxy, there are many stars that have pairs or triplets. The protostar can break into two or three blobs as they spin and this would, in turn, create multiple stars.

As mentioned above, it took 50 million years for our Sun to reach maturity. The same can often occur for other stars as well. As the star matures, it fuels itself by nuclear fusion of hydrogen. What this means is that the hydrogen is fused together with another hydrogen–different isotopes of course–and this results in helium. However, the amount of energy that comes off from this fusion is what powers the sun. It's this consistent flow of energy from the core that prevents the star from caving in on itself. It's also because of this that the Sun is as bright as it is.