What physicists and astronomers do, is they look at how things work here on earth and where we can observe things.
For example, we can observe that the earth orbits the sun, we know that orbit takes a year, and it’s pretty stable. And from that and the speed and orbit of other planets, we can calculate the mass of each. And with the same math, we can do it for our galaxy.
But when we look way, way deeper into the universe, we can only see: electromagnetic things, that is light and radio. And by observing that or how it behaves, in the case of black holes, we can say where things are, what they’re like and how they move. Including how big they are, how massive, we can calculate how much mass is required to keep a galaxy together.
The problem is the movement we can see, doesn’t match the calculated weight and gravity of the things we can see.
The solution is that we assume that things do behave as we think they do, we just can’t see it. The weight that we can directly or indirectly observe accounts for about 5% of the effect we can see. So we make up the rest. That’s “dark matter”. Not because it’s different from what we know, but because we can’t observe or “see” it.
Or we’re wrong about the rules that we use to calculate stuff or things are happening we don’t understand yet.
And we recently discovered a clump of dark matter big enough to form a gravitational lens - we could actually see it curving light.
This helps show that dark matter isn’t evenly distributed, it’s not that we just need to add a multiplier to some equation; it’s something that ‘exists’.
What physicists and astronomers do, is they look at how things work here on earth and where we can observe things.
For example, we can observe that the earth orbits the sun, we know that orbit takes a year, and it’s pretty stable. And from that and the speed and orbit of other planets, we can calculate the mass of each. And with the same math, we can do it for our galaxy.
But when we look way, way deeper into the universe, we can only see: electromagnetic things, that is light and radio. And by observing that or how it behaves, in the case of black holes, we can say where things are, what they’re like and how they move. Including how big they are, how massive, we can calculate how much mass is required to keep a galaxy together.
The problem is the movement we can see, doesn’t match the calculated weight and gravity of the things we can see.
The solution is that we assume that things do behave as we think they do, we just can’t see it. The weight that we can directly or indirectly observe accounts for about 5% of the effect we can see. So we make up the rest. That’s “dark matter”. Not because it’s different from what we know, but because we can’t observe or “see” it.
Or we’re wrong about the rules that we use to calculate stuff or things are happening we don’t understand yet.
And we recently discovered a clump of dark matter big enough to form a gravitational lens - we could actually see it curving light.
This helps show that dark matter isn’t evenly distributed, it’s not that we just need to add a multiplier to some equation; it’s something that ‘exists’.
Personally, I’m a big fan of “there are unknowns in the universe”, so imo they found lens, which could be a gravitational lens ;)
Cool nontheless.
That is literally what dark matter is.