Question: how was the earth created?

Derek McKay-Bukowski answered on 13 Jun 2011:

The earth was created from the remains of an exploded star which condensed to form the sun, earth and other planets.

Many billions of years ago, there was one (or possibly more) stars in this part of our galaxy. These stars were extremely large. They use nuclear fusion to ‘burn’ up all their hydrogen to form helium. This is then burned that up to form carbon and oxygen and other heavy elements. At some point, this burning starts making iron; yes, the metal… but heated sooooooooo hot that it is a superheated plasma. Now this iron doesn’t burn. When this happens the star begins to collapse until this sudden pressure causes a violent explosion. This is called a supernova. The star blows itself apart, and the hydrogen, oxygen, iron and all the other elements get blasted out into space. The explosion is so strong, that it can also create other rare elements too, like gold or uranium.

Now, this material will float about in space for a while. Sometimes it just drifts away, but sometimes it starts to condense. This is sort of like the way that water condenses into a cloud. As that material starts to come together it forms regions of dense material, like enormous droplets in space. Droplets the size of planets.

In fact these are the planets. Still very hot and molten. With only their own gravity, they form spheres – more-or less-perfectly round shapes (that’s why the earth is round). Different spheres at different distances from the centre sphere then cool and become the planets. Their atmospheres stabilise and they become like what they are today.

Now, if there is a lot of mass in any of these spheres, and there is enough hydrogen around, then they can start to collapse to the point where nuclear fusion can occur. They then start burning as stars. Usually the sphere right at the centre will be big enough for this. And that’s what our sun is (think of it as a recycled star!).

Sometimes the planets can be so big that they do that too. Jupiter (the largest planet in our solar system) is big, but it is NOT big enough to star burning like a star. So don’t worry, we’re safe.

However, sometimes there are solar systems where there is enough material to get a second star going. These systems then are called double-star systems. In fact, it is even possible to form triple star systems. Alpha Centauri (the nearest star system to our own solar system has three stars).

In any case, the earth is relatively small and rocky and has a nice atmosphere… so it is a great place for life to evolve. And that life comes from the chemicals that make up the earth, which in turn come from that exploded star.

So, if someone says that you are “star dust” then, yes, in a way they are absolutely right!