And the heavens shall praise Thy wonders, O LORD:
Psalm 89:5
Psalm 89:5
"Fact number five presents our next paradox.
suggested that something fundamental was wrong with our understanding of how galaxies form and evolve. Computer simulations consistently show that dark matter should clump together most densely at the center of galaxies, creating what scientists call a cuspy distribution.
Observations of actual galaxies, including our own Milky Way,
show that dark matter appears to be distributed much more evenly than simulations predict. Instead of the sharp mountain peak, we see something more like a gentle hill. The dark matter seems to form what's called a core, a region of relatively the galaxy density at constant center.
For decades, astronomers could only find about a dozen satellite galaxies around the Milky Way. Where simulations predicted thousands, reality offered only a handful.
This became known as the missing satellites problem and it
But just when scientists thought they were beginning to understand this discrepancy, the universe threw them another curveball.
Advanced surveys using more sensitive instruments began discovering satellite galaxies that had been too faint to detect before.
This should have solved the missing satellites problem, but instead it created an entirely new puzzle.....we now appear to have too many satellite galaxies.
Recent estimates suggest there may be over 500 small galaxies orbiting the Milky Way, more than twice what the most optimistic simulations predict.
*We've gone from a shortage to an overwhelming abundance, and our models can't explain either situation satisfactorily. This dramatic reversal tells us something profound about the limitations of our current theories. when your predictions can be wrong by factors of 10 or more and then swing wildly in the opposite direction.
As new data arrives, it suggests that the fundamental assumptions underlying those predictions might need serious reconsideration.
Let's delve deeper into the strange behavior of dark matter itself, assuming it exists as our models propose.
Imagine a mountain with very steep sides rising to a sharp peak.
Scientists have proposed various mechanisms that might transform the predictor spy distributions into the observed caused cue. But none of these solutions work convincingly across all types of galaxies.
The mismatch between predicted and observed dark matter distributions becomes more pronounced in smaller galaxies.
The very places where we should be able to test our theories most precisely in small nearby galaxies where we can measure everything in great detail are exactly where our theories perform most poorly."
SleepyPhysicist
