Asteroid with elements beyond the periodic table. Well, apparently the asteroid 33 Polyhymnia, which is located in the main belt between Mars and Jupiter, isn't the only "compact ultradense object" that's been found, it's just the heaviest. According to this article, the densest stable element is osmium (element 76 on the periodic table). I did not know that. They key word is that sentence is "stable". The periodic table goes up to element 118, now called Oganesson, which is the heaviest element ever synthesized on Earth. But if density calculations on these "compact ultradense objects", including 33 Polyhymnia, are correct, then in order to be as dense as they are, have to contain heavier elements.
Osmium has a density of 22.59 g/cm^3, about twice that of lead. According to the article, the researchers made a mathematical model that suggests an element that would be element 164 on the periodic table would have a density between 36.0 and 68.4 g/cm^3.
But the asteroid 33 Polyhymnia has a density of about 75 g/cm^3.
I have to admit, I just don't see how this is possible. How does something as small as an asteroid have enough gravity to become compact enough to create these kinds of densities?
If you're wondering about the mathematical model, they say, "We solve numerically the relativistic Thomas-Fermi model of an atom."
I never heard of the Thomas-Fermi model so I looked it up. The basic idea is that instead of calculating the wave function for every electron, such you would do with the Schrödinger equation, you treat the electron density as a continuous distribution. As the number of electrons goes up, trying to calculate every electron, such as with the Schrödinger equation, gets harder and harder, but the Thomas-Fermi model actually gets more and more accurate. So it's the way to go for elements with boatloads of electrons. Accuracy is further improved by taking into account relativistic effects for fast-moving electrons.
Beyond the periodic table: Superheavy elements and ultradense asteroids
