Dark Matter and the Frontier of EUV Astronomy
How the discovery of dark hydrogen provides a mundane (and profound) resolution to the Dark Matter problem.
In 1933, Caltech astronomer Fritz Zwicky noticed that the galaxies within the Coma cluster were orbiting one another too quickly. Much too quickly.
In the solar system, the orbit of an object is related to its mass and its velocity. If it is moving too fast, like the asteroid Oumuamua, the orbit becomes hyperbolic and the object leaves the solar system. If it is moving too slowly, it falls into the sun. The same rules apply for stars in a galaxy, and galaxies within a galactic cluster.
Based on the visible luminosity of the Coma galaxies, they should have been orbiting one another at about 80 km/s. Instead, they were moving over 1–2,000 km/s. He was led to speculate:
“dark matter is present in much greater amount than luminous matter.”
There was more stuff out there, and it was ‘dark.’ (Or, if the six-year-old Calvin had naming rights, it could have been the “invisible omnipresent lurking mass of doom.”)
Sinclair Smith found the same thing after studying the Virgo cluster. He theorized that the missing mass was contained in large clouds of gas that formed halos…
