Being in the Universe is kind of like fish in a fish tank; you don't appreciate it because it's all around you. But science has discovered some incredible things about the space in which we live. Here are seven that might make you see everything a little different.
1. Everything Is Made of Stars - The elements in our universe are made up of basic atoms, and those elements combine into compounds. Most of the basic elements are created by reactions inside stars, which means you and everything around you is made of stars.
2. Astronomers Can See Two Billion Years Back in Time - Modern telescopes allow astronomers to see galaxies two billion light years away, which means the light we see took two billion years to reach us. That means the light we see started out billions of years ago. We're literally seeing back in time.
3. The Universe is Organized - Our solar system revolves around the center of the Milky Way Galaxy, along with all the other solar systems in the Galaxy. Scientists have discovered that the Milky Way Galaxy is bound together with other galaxies into a group. That galaxy group travels through the Universe along with other galaxy groups to form a galaxy cluster. And the galaxy clusters are grouped together into superclusters. And those superclusters are in motion throughout the universe.
4. There is No Such Thing as "the Universe" - There is no totally agreed upon definition of the term "universe." You might think the definition is obvious: the Universe is everything. But does that include things we haven't experienced yet like light from distant galaxies? What about time? If time is part of the universe, does "universe" include the abstract like the future? If we include the abstract, what about mathematics? Here's a video that explains it better than I could.
5. The Universe is Flat - Though science and observation has definitively proven that the Earth is round, scientists have also calculated that the Universe itself is flat. We know this because (among other things) of the way light curves.
6. There Are More Stars Than Sand - Many poets have compared the stars in the sky to grains of sand on the beach. But it's more complex than that. Current estimates about the number of stars in the Universe are 100 sextillion (that's twenty-three zeroes). That means there are more stars in the Universe than there are grains of sand on the planet Earth.
7. Most of the Universe is Empty Space - When most of us think of the universe, we think of stars and planets and galaxies. But the reality is that most of the universe is just empty space. Isaac Asimov illustrated it this way: think of a perfectly square building twenty miles long, twenty miles wide, and twenty miles high. That building is the universe. If you collected together all the matter in the universe in that building, it would be only a single grain of sand.
Which was your favorite fact about the Universe? Do you know any facts you can share?