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90% of the Universe Found Hiding In Plain View
The Bad Astronomer writes "As much as 90% of previously hidden galaxies in the distant Universe have been found by astronomers using the Very Large Telescope in Chile. Previous surveys had looked for distant (10 billion light years away) galaxies by searching in a wavelength of ultraviolet light emitted by hydrogen atoms — distant young galaxies should be blasting out this light, but very few were detected. The problem is that the ultraviolet light never gets out of the galaxies, so we never see them. In this new study, astronomers searched a different wavelength emitted by hydrogen, and voila, ten times as many galaxies could be seen, meaning 90% of them had been missed before."
And how do they know that they've found 90% of what was previously hidden?
Maybe there's more hidden than they thought was hidden.
Is the size of the universe so widely agreed-upon? Far be it from me to challenge a headline in Science, but I'm just a little curious about this assertion.
It's because of gravity. In order for galaxies to look the way they look, there has to be a certain amount of gravity. Too much and it gets sucked inward faster and would look very different. Too little and they fly apart.
Thus, we know how much mass is required for the effect we see out of gravity.
But previously they could only see about 10% of the mass they were expecting.
Some said our theories were wrong. Others that 'stuff' must exist that is so weird and different, and called that dark matter.
Yea, it was always there, we were just looking in the wrong way (If this is correct of course)
This means dark matter is found, because it is no longer a requirement that dark matter must not interact with visible light. This stuff does just that, and makes up the full 100% that we were expecting originally.
Any dark matter now would put the universe at over 100% mass, which would just be silly.