The universe is a pretty weird place. That's because even though we have a good idea about how it should be, our observations are often misleading. If not misleading, sometimes they just don't reveal what we expect to!
How frustrating it must be for mathematicians and physicists when they prove the existence of something mathematically but it doesn't show up in their observations!
Take dark matter and dark energy for instance. These two are supposed to form 95% of the universe. But, despite scientists' best efforts, we have absolutely no idea how to observe them. We can merely observe their effects on "regular" matter but we can't view them directly.
Even with the visible universe, that makes up 5% of reality, we had only managed to "find" half of it. Scientists have only now found the other half of the visible universe.
Finding Universe
Scientists had calculated a long time ago how much matter there is in the universe. However, the subsequent observations only showed half the Baryonic matter (regular matter) that we had expected to find.
This had been frustrating for the longest of time, as one can understand! In fact, many scientists have said over the years that it almost feels embarrassing that they couldn't find the rest of the missing half.
Now, however, they have done it. They have finally done it! And to do it, they used their ability to tract fast radio bursts as they pass our planet. You might have heard about these radio bursts coming from deep space on the news.
More often than not, they end up being speculated as signals from alien beings. Not by the scientists, but by the regular folks. But astronomers have now used these to complete the Baryonic matter map.
Source please. :)
Here it is :
https://www.nature.com/articles/s41586-020-2300-2