Question: How was the earth and other planets around it created when the big bang happened?

Roberto Trotta answered on 17 Jun 2014:

When the Big Bang happened (that is 13.7 billion years ago, or 13 700 000 000 years ago!) the Universe was very dense and very hot. It was made only of light, dark matter, hydrogen and helium (two light gases).

But as the Universe expanded, it cooled down, until it was cool enough for the first stars and galaxies to form, because gravity would attract lumps of matter together. This took a long time — perhaps 500 million years.

The very first generation of stars then burnt all their fuel and in so doing they produced inside them all the elements that we are made of (carbon, iron, silicon, oxygen, etc…) and without which we could not live. These first stars exploded and spit out all those elements into space.

Out of that stardust, a new generation of stars was born, and then died, and then another one came along: The Sun is part of this third generation of stars.

So the Sun and the solar system, including the earth, were formed when this stardust from the explosion of another star was gathered around by gravity into a spinning disk, out of which the central star and all the other planets where formed. This happened about 5 billion years ago, so about 7 or 8 billion years after the Big Bang. It took that long for our solar system to be put together!