Teacher: Alright, class. Since your test is tomorrow who wants to tell me what dark matter is?
Teacher: Yes, Alkina?
Alkina: Dark matter is the most dominant matter in the Universe. Of all matter and energy, dark matter makes up about 24% of the Universe.
Teacher: Very good. Jios, how do we know dark matter is here if we can’t see it?
Jios: Oh! Because of how fast galaxies rotate, they shouldn’t be rotating that fast.
Frelo: And because of gravitational lensing… galaxies and clusters bend light as if there is much more mass there than we see.
Teacher: Now, can anyone name two scientists who greatly helped in the understanding of dark matter? Yes, Vivian?
Vivian: Vera Rubin who measured galaxy rotations and Fritz Zwicky who measured galaxy clusters.
Teacher: Very good. Make sure to re-read the chapter on dark matter before tomorrow, and happy holidays.
In human speak please!
The students address many of the primary forms of evidence for dark matter and the scientists responsible for discovering that evidence. However, the Universe is a big place and as such there is more to dark matter than just what has been covered in this year’s Special Episodes. For further inquiry, here is one more piece of evidence for dark matter:
Detailed maps of the Cosmic Microwave Background imply that dark matter must exist. If the Universe was composed of only “normal” matter then the various fluctuations of the CMB would be different than what is observed. What is observed indicates that there is dark matter.
Is that all?
Evidence for dark matter – Chandra X-ray Telescope’s website about dark matter and the evidence for it.