A little more deepening to the Dark Matter:
How quickly, for example, a moon orbits a planet is only a matter of the distance and gravity of the planet.The mass of the moon makes no difference. The mon orbits the earth in about 300,000 km and takes about 28 days. An Apollo debris at the same distance also takes 28 days. Geostationary satellites are located at a distance of about 36,000km and then need 24 hours for orbit.
From the orbital velocity and the distance it is now possible to calculate the mass in the center of the track.
The whole thing also applies to suns orbiting the center of a galaxy.
Now the mass in the center of galaxies has been calculated using stars in the inner area.
Then there was the first problem, there was too much mass in the center, at least more than was visible in stars.This was then the first evidence of black holes (SL) in the center of galaxies.
SL are invisible, but can hide badly.When they eat stars and gas clouds, the victims glow through the acceleration and indicate exactly where the SL is hiding. (This is similar to the SiFi movies about invisible monsters. In fog or rain you can see them because there can be no fog or rain where they are.)
Another effect is the gravitational lens.
Even our sun deflects rays of light in an arc. So you can see stars next to the sun, which are actually just behind the sun.Astronomers were able to prove this during a solar eclipse, proving Einstein’s theory.
An SL has an even greater effect than the sun, it can distract the light from behind it around it.So when an SL moves across the sky, the background is distorted, as if you were driving over it with a magnifying glass.
So an SL influences its surroundings and betrays itself as a result.
The enormous gas and dust clouds also have a lot of mass, but they also betray themselves because they affect the light.A cloud of dust is like a cloud in the sky. It also darkens, more or more, the light from behind it.
A gas cloud is transparent at first glance.However, gases absorb very specific narrow spectra. This allows you to use a spectral analysis to determine what such a gas cloud is composed of.
Back to our galaxy.
So a mass had been calculated for the center.This allowed the orbital velocities to be calculated for each distance to the center.
But the stars didn’t want to behave appropriately.Above all, it didn’t fit that stars in the middle distance were way too fast, so there should be more mass in the center, but those outside on the edge, then matched the calculated mass in the center again?
OK, measurement error, ora measurement accuracy, you always have, but 90% deviation could not be explained by it!
The first idea was that there are a lot more clouds of gas and dust in the middle distance and there must also be a huge amount of black holes.At 90% deviation, however, 9x more SL and clouds would have to be present than known.
You can’t go through the slats like that!And as I wrote, they interact with light.
The first emergency solution was dark matter, which has a gravitational effect but does not produce any other effects.
We ourselves are constantly surrounded by dark matter, but we do not notice it and cannot prove it (until now).
At least the astronomers are satisfied with dark matter for the time being, if they use it in their formula, their world is right again.
What dark matter is, no one knows to this day, and there are theories about it, but still too many to be able to derive anything from it.
It is currently hoped that the LHC of CERN will find any clues to the dark matter.However, this may only be possible with a successor to the LDC.