This may be surprising, but we do not know what the majority of the universe is made up of. Seriously, we do not know. Surely you are thinking: "But, of course we know! It's made up of galaxies, stars, planets, black holes, comets, asteroids and all those interesting things in space! "
Yes, there are many interesting things in space, but if we add everything up, it's a very small portion of the whole universe. There is much more to know. And we can not understand exactly what it is.
When scientists study our universe, they observe that it is expanding. But if the universe were only composed of galaxies, stars, planets, and other things we already know, it should not be expanding. There's something out there. There has to be an energy that is causing the universe to expand. It's just that we do not know what that energy is. We do not know where it comes from. But we do know that it is there. Scientists call this energy dark energy.
We do not know much about dark energy, but we do know that there are so many. The 68% of the universe, that is, almost two thirds, is composed of dark energy.
There are also things in outer space that have gravitational force. We can see their attraction to matter, like stars and galaxies. But not common stuff. It's not a black hole. It's nothing we've ever heard. But it is certainly there. Scientists call it dark matter.
Like dark energy, there is much that we do not know about dark matter. But apparently, 27% of the universe, or about a quarter, is composed of that strange thing.
Together, dark energy and dark matter make up 95% of the universe. That's almost the whole universe. That means that what we know and understand is only 5%. Energy such as light, heat and x-rays, along with matter, people, elephants, planet Earth, the sun and all galaxies are only 5% of the universe. That's not much.
Dark matter and dark energy pose some of the most important questions in the study of space and physics. Many scientists are using observations and calculations to find out what they are. This will help us to understand more about our incredible universe, where there is always more to discover and much more to learn.
Whatch video:
Source: nasa.gov
Credits: Kristen Erickson - Kurzgesagt – In a Nutshell
