The extra-terrestrial kind, that is.
I like comic books. Part of what you see in comic books is that there’s stuff on other worlds that we don’t have, sometimes even entire elements that we don’t have. What I’d like to know is how likely it is that there are all kinds of other stable chemical elements (you know, the kind that don’t exist for micro-seconds in a laboratory, or somesuch) on other planets, out there. Does anyone have an idea as to how we could tell?
Thanks.
bamf
don’t just exist for micro-seconds in a laboratory, that is.
bamf
Moderator’s Note: This question should have a factual answer, so I’ll move it to GQ.
Atoms are made of protons (positively charged, massive particles) and neutrons (electrically neutral massive particles), both found in the atomic nucleus; and electrons (light, negatively charged particles) which surround the nucleus. What determines if an atom is one or another element is its “atomic number”, which is essentially the number of protons in the nucleus. Normally, there is an equal number of electrons and protons in any atom (under some circumstances, electrons may be gained or lost, forming a negatively or positively charged “ion”). The number of neutrons is usually roughly equal to the number of protons; atoms with the same atomic number but different numbers of neutrons may exist; these are referred to as “isotopes” of that element. For example, hydrogen (atomic number 1) has 1 proton and 1 electron. An atom with 1 proton, 1 neutron, and 1 electron is an atom of the isotope of hydrogen known as deuterium. An atom with 1 proton, 2 neutrons, and 1 electron is an atom of the isotope of hydrogen known as tritium. Tritium is radioactive; radioactive isotopes eventually decay (break down) into stable isotopes, releasing some form of radiation in the process.
The element with atomic number 2 is helium (2 protons and 2 electrons; the most common isotope of which has 2 neutrons). On even the most distant planets, millions of light years away, there won’t be anything with atomic number “1.5”–there’s nothing out there with one and a half protons. All the elements with atomic numbers 1 through 92 (uranium) are found naturally occuring on this planet. (Except technetium, atomic number 43, which is radioactive and must be artificially produced in nuclear reactors.) So, the elements found on Earth are the same elements found on distant planets. Except for those super-heavy unstable atoms beyond uranium, there’s just no place to put a new element. We can even detect the makeup of distant stars by using spectroscopes, and all available evidence is that the rest of the Universe obeys the same physical laws as are found here on Earth. There may be some relatively stable (“Ooh–it lasts for a whole second!”) super-heavy elements beyond those already discovered, but such elements won’t be any more stable on the other side of the Universe than they are right here in Stanford or Moscow or wherever.
Correction: Element 61 (promethium) is also artificially produced and not found in nature.
I have nothing important to add, but I just wanted to point out that “promethium” is the coolest name for an element ever.
The inclusion of ‘alien elements’ in fiction probably comes from the discovery in the late 1800’s that certain spectral lines in the sun, and nebulae didn’t match up with those of any known earthly elements. The two alien elements were Coronium, found in the solar corona, and Nebulium, found in gaseous nebula. Coronium turned out to be the new element Helium. The Nebulium, spectra was found (in 1931) to arise from oxygen atoms in an extreme vacuum.
As I understand it, the reason for all the elements existing is stars going supernova, engulfing the planets surrounding them, then another star forming, polluted with whatever elements the planets happen to be carrying. The elements then fuse, and the process goes on until you get to Uranium. Am I correct with this theory?
Now, is it possible to form stable isotopes beyond Uranium given enough Solar generations, or is anything beyond Uranium pretty much not going to form naturally, ever?
I’m no expert, but the process is known as nucleosynthesis. This link might be a helpful overview.
Have a look at this extended periodic table. Click on unbihexium with atomic number 126 and unbinilium with atomic number 120.
Close enough. Any planets the exploding star may have had are irrelevant; the fusion occurs in the star before it blows (for elements up to iron) or in the supernova itself (everything heavier). Elements above uranium would be produced in a supernova explosion, but the problem is that they aren’t going to stick around. It doesn’t matter how it’s produced: An atom with a given number of protons and neutrons is going to be exactly as stable or unstable anywhere in the Universe. And some elements (notably including anything above uranium) have no isotopes which are stable at all. Once you get past californium (atomic number 98), the half-lives are all less than a year, and for the really high ones, you might hope for a fraction of a minute for the occasional “island of stability”. And of course, on astronomical time scales, you can forget about that.
Poul Anderson, among others, has devised astrophysical scenarios that result in “planets” (using the term slightly loosely) which incorporate metastable elements from those hypothetical “islands of stability” which Chronos referenced. (A metastable element is one that is in fact radioactive but with a half-life measured in the millions of years, such as uranium and thorium.) Devising interesting properties for such elements that advance the story line can be intriguing. In particular, since such “planets” will be extremely rare, the possession of one, or of mining rights on one, is of vast strategic economic and political importance within the storyline.