Discover
/
Article

The composition of our universe

APR 01, 1950
A survey of the evidence that suggests the universe is remarkably uniform in its chemical composition.

One of the more difficult fundamental problems which confronts science today is that of determining the chemical composition of the matter of which our universe is made. Man, bound to the surface of his planet, can see the billions of stars which exist within the galaxy of which his sun is a member, and the billions of galaxies extending in all directions as far as his telescopes can penetrate; but he has only the light that the stars emit with which to work. He knows that a very large amount of matter is scattered throughout interstellar space; but he cannot sample it. He can see the other planets within his solar system; but he can study only the light that they reflect from the sun. He is even prevented by the thick solid crust under his feet from sampling the interior of his own planet.

This article is only available in PDF format

More about the authors

Harrison Brown, University of Chicago.

Related content
/
Article
A half century after the discovery of Hawking radiation, we are still dealing with the quantum puzzle it exposed.
/
Article
Since the discovery was first reported in 1999, researchers have uncovered many aspects of the chiral-induced spin selectivity effect, but its underlying mechanisms remain unclear.
/
Article
Metrologists are using fundamental physics to define units of measure. Now NIST has developed new quantum sensors to measure and realize the pascal.
/
Article
Nanoscale, topologically protected whirlpools of spins have the potential to move from applications in spintronics into quantum science.
This Content Appeared In
pt-cover_1950_04.jpeg

Volume 3, Number 4

Get PT newsletters in your inbox

pt_newsletter_card_blue.png
PT The Week in Physics

A collection of PT's content from the previous week delivered every Monday.

pt_newsletter_card_darkblue.png
PT New Issue Alert

Be notified about the new issue with links to highlights and the full TOC.

pt_newsletter_card_pink.png
PT Webinars & White Papers

The latest webinars, white papers and other informational resources.

By signing up you agree to allow AIP to send you email newsletters. You further agree to our privacy policy and terms of service.