Mercury's molten core Options

[Guest_AlexBlackwell_*]

The embargo won't be lifted for a few more hours, but note that the May 4, 2007, issue of Science will have an interesting paper Margot et al. (and accompanying Perspectives piece by Sean Solomon) regarding Mercury and a possible molten core, a paper that also makes the cover.

[edstrick]

"Could the heating be a result of tidal forces? As I recall, Mercury has a fairly elliptical orbit."

Tidal heating involves dissipation of energy. The result is that the orbit would circularize over time. Io and Enceladus are in resonances that keep re-ellipticizing <new word?> their orbits. I don't know the timescale for plausible orbital ellipticity evolution at Mercury, but that it hasn't gone circular over 4.5 billion years argues that the crust is pretty rigid and does not dissipate energy. A fluid core is so fluid that it doesn't dissipate tidal energy efficiently.

[Marz]

Looks like more clues to a molten core:

http://www.nasa.gov/home/hqnews/2008/oct/H...er_Mercury.html

with this AP article:

http://news.yahoo.com/s/ap/20081029/ap_on_sc/sci_mercury