How about further away? The sky extends for miles above you and wraps around the entire Earth along with 7 billion other people spread throughout the globe in distant countries.
How about even further away? There are billions of stars clumped around us in a galaxy, many of which have planets of their own. There are billions of galaxies, spanning unfathomable distances.
It seems the universe is totally filled with things! But is it?
Almost everything is made of atoms. Inside an atom, there are tiny particles "orbiting" a clump of particles in the center called the nucleus. These particles are very, very small. To put things into perspective, if an atom where the size of an entire football stadium, the nucleus would only be about the size of an apple in the center, while the orbiting particles would be microscopic in the bleachers. The atom is almost completely empty.
The nucleus itself is made up of mysterious particles called quarks. The quarks are believed to be even smaller to the nucleus, then the nucleus is to the atom. The nucleus itself is almost entirely empty.
If the planets and stars are made up of these atoms, then that would mean they are mostly empty. Furthermore, the planets and stars are very far apart.
The solar system is over 7 billion miles across. The earth is only about 4 thousand miles across. If the solar system is thought of as a disk, then we can estimate that about 1.75 billion earths could fit on this disk. NASA once sent a probe out of the solar system. As it was leaving, it pointed its camera at the Earth and took a high resolution picture. There wasn't very much to see though. The Earth was only a spec of dust in an empty picture. The entire solar system consists of just a few of these specs of dust, which are the planets and asteroids.
Light travels at about 186,000 miles per second. It is fast enough to zip around the earth 7 times in a single second.
The stars themselves are so far apart that it would take light four years to go from our sun to the nearest star. Between the stars is mostly emptiness. Galaxies are even further apart.
When things are put into perspective, we realize the entire universe is mostly empty.
Hi Nathanael,
ReplyDeleteIt's really interesting to think about the things that make up the universe. It's amazing that everything is made up of tiny particles and atoms and how big the universe is. I have about zero knowledge of astronomy but it's really interesting to read what you posted about how vast the universe is and how everything is orbiting around each other. Some things I've always wondered was how some planets have a ring around it like Saturn, why different planets have different gravitational pulls, and how shooting stars form.