Isaiah 44:24
"Now we encounter one of the most precise relationships in all of astronomy and one that presents a serious challenge to our understanding of how galaxies work.
The Barionic Tully Fisher relation despite its intimidating name describes something quite elegant.
"Now we encounter one of the most precise relationships in all of astronomy and one that presents a serious challenge to our understanding of how galaxies work.
The Barionic Tully Fisher relation despite its intimidating name describes something quite elegant.
There's an incredibly tight correlation between how much normal matter a galaxy contains and how fast that galaxy rotates.
This relationship is so precise that if you tell an astronomer the mass of visible matter in a galaxy, they can predict its rotation speed with remarkable accuracy.
This might not sound unusual at first, but here's the catch. In our current model, the rotation speed should depend primarily on the amount of dark matter, not the visible matter.
Dark matter and visible matter are supposed to be entirely separate entities that barely interact with each other. Dark matter doesn't emit light, doesn't absorb light, doesn't collide with itself or with normal matter. It exists in its own shadowy realm, affecting things only through gravity. This relationship is so precise that if you tell an astronomer the mass of visible matter in a galaxy, they can predict its rotation speed with remarkable accuracy.
This might not sound unusual at first, but here's the catch. In our current model, the rotation speed should depend primarily on the amount of dark matter, not the visible matter.
Q: So, why would there be such a precise relationship between the amount of visible matter and the overall gravitational behavior of a galaxy? It's as if you discovered that the number of birds in your backyard perfectly predicted the speed of traffic on the highway outside your house.
There's no obvious reason why these two things should be connected. Yet, the correlation is so tight and universal that it demands an explanation.
This relationship suggests that visible matter and the gravitational effects we attribute to dark matter are intimately connected in ways that our current theories cannot explain.
It's not just that they happen to coexist in galaxies. They appear to be coupled together by some mechanism that remains completely mysterious."
SleepyPhysicist