Dark Matter Measurements

ksp0704 writes: "According to this article at space.com, scientists have finally measured the approximately 90% of the universe we can't see (the dark matter)." I'm sure it will continue to be a topic of debate for years, but two independent measurements agreeing is a good sign.

Comments

You mean you don't know?!

[crashnbur]

Let me guess, you didn't read the article, and therefore have no clue how such measurements are made, and rushed your reply in so that you could nab a first post? Here, let me help you out:

According to the leading theory, an enormous nuclear explosion called the Big Bang happened 13 billion to 15 billion years ago. From it, the universe appeared in an instant, but as a billion-degree mess of neutrons, protons and electrons. The explosion was so energetic that nothing could come together close enough, for long enough, to form atoms. But the universe expanded and cooled so rapidly that within three minutes protons and neutrons bonded in twos and fours, and formed all the atomic nuclei in the universe. This Big Bang Nucleosynthesis determined how much normal matter would ever exist.

Just how much matter that was can be estimated from observing the most recently formed stars and galaxies, because they are fueled by the hydrogen atoms formed from those original nuclei of twos.

Fields explained that young stars, like our Sun, are just now fusing that original hydrogen into helium whereas older stars fuse helium into oxygen and iron. Because the hydrogen fuel has not been converted, scientists are able to measure the proportion of original normal matter to dark matter.