Saturday, March 7, 2009

Superdense Elements

The heaviest natural elements are of course Osmium and Iridium, with densities around 22.6. Osmium beats iridium 22.610 to 22.560 according to Wikipedia, but I recall reading older books where they weren't known to enough sig figs (significant figures) to be sure. (Then again, my 1842 astronomy book says the asteroids have huge, thick atmospheres, that meteors are static electricity, and intelligent life lives on the sun - no joke - so maybe newer books are better). That means that a 1-cube of either weighs three-quarters of an ounce - 22 times the same amount of water. Lead is only half as dense as the two at 11.342g/cm3, and iron a third at 7.8.

However, some of the transuranium elements may be even denser. According to this handy list, Seaborgium and Meitnerium are estimated to have desnities of 35, Bohrium 37, Dubnium 39, and Hassium an incredible 41, or almost 1.5 ounces per cc. Of course, the total yield ever of Hassium is a couple hundred atoms, but still.

Of course, inside a Neutron Star the densities might reach over 1014 g/cc, and at 10-44 seconds (the Planck time) after the Big Bang, the universe's density was around 1093, an utterly incomprehenisble number.

Also, random fact: Bismuth-209 (Bi209) has a half life of over 1019 years, making it technically (but not for practical purposes) radioactive, and that that was predicted before it was detected.

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