Is there such thing as stardust?

Answer 1

Yes.

Most of the universe is made of hydrogen, the simplest element. Scientists believe that in the very early universe, hydrogen was all there was; there were no other elements.

Large areas of hydrogen gas will come together because of their mutual gravity. If there is a large enough amount, the hydrogen will be squeezed together by gravity and heated to that the hydrogen atoms smash into each other and fuse together to form helium, and release a large amount of energy. This energy heats the surrounding hydrogen causing IT to fuse, and so on in a giant chain reaction. This is how a star is born.

After millions of years, much of the hydrogen will have been fused into helium. With enough heat, three helium atoms can fuse together into carbon, which releases even MORE energy. When the amount of carbon is high enough, the carbon and helium can fuse into more complex elements which are heavier and heavier. Each heavy atom, when it fuses, releases even MORE energy and creates heavier and more complex elements - until it gets to iron.

When iron fuses, it no longer releases energy; it absorbs energy from the surrounding gas in the star to create heavier elements. When this begins, it creates a shock wave inside the star that causes the star to explode in a supernova. This generates so much energy that very heavy elements are formed, but the core of the star is crushed into such a heavy mass that it can create a neutron star or a black hole. The outer layers of the star, with most of the heavy elements, are blasted out into space. Away from the heat of the star, the gasses will condense into dust. Star dust.

After many millions more years, some of that dust and gas will be attracted together to form new stars, and the heavier elements can be drawn together to form solid masses. Some of these solid masses become together to form planets, but many more of them continue to float about in space.

The planets with their heavy elements like carbon, silicon and iron, and some very heavy elements like gold and uranium, can (over millions or billions MORE years) develop atmosphere, oceans and life. Life is made of carbon, oxygen and nitrogen, in addition to the original hydrogen.

So are you and I and all living things on Earth. The Earth, and everything in it, is made of stuff that was blown into space from the heart of a supernova explosion.

YOU are star dust!