The content you've requested is available without charge only to active Sigma Xi members and
If you are an active member or an individual subscriber, please log in now in order to access this article.
If you are not a member or individual subscriber, you can:
Because it is impossible to penetrate to the centers of planets, scientists must probe with experiments and simulations. Three techniques have provided insights: diamond-anvil cells, shock-wave experiments and molecular simulations. Each tries to create tiny worlds in which matter is compressed to high pressures where extreme transformations take place. To date, these methods have shown that Neptune must be filled with methane that dissociates to form hydrocarbon chains as pressure and temperature increase with depth, and finally there are likely to be diamonds in the planet's core. Experiments have shown how hydrogen can become a metallic fluid at the extreme pressures and temperatures that may characterize most of Jupiter's interior. Finally, it appears that Earth's core may be almost twice as hot as we thought—as hot as the surface of the sun.
Connect With Us:
An early peek at each new issue, with descriptions of feature articles, columns, and more. Every other issue contains links to everything in the latest issue's table of contents.
News of book reviews published in
and around the web, as well as other noteworthy happenings in the world of science books.
To sign up for automatic emails of the
American Scientist Update
issues, create an
, then sign up in the
My AmSci area
JSTOR, the online academic archive, contains complete back issues of American Scientist from 1913 (known then as the Sigma Xi Quarterly) through 2005.
The table of contents for each issue is freely available to all users; those with institutional access can read each complete issue.
View the full collection here.
Receive notification when new content is posted from the entire website, or choose from the customized feeds available.