MadSci Network: Chemistry Query:

From what I understand, all of the known elements have been discovered on Earth (or in the case of unstable elements, have been created on Earth in particle accelerators), with the exception of helium (a fact that I would have forgotten if it weren�t for fellow Mad Scientist Dan Berger).

Helium was discovered in 1868 by Norman Lockyer through spectroscopy. Using this technique, the light emitted from the sun was broken up into its constintuent colors. All the components of the spectrum could be accounted for except one. Twenty seven years later, helium was finally discovered on Earth, and when the spectrum of this new element was compared to that obtained from the sun it was found that they matched! Helium, originally detected (but not originally identified), in the solar spectrum was now found to exist on Earth!

Slightly related to your question: there is one instance where observations conducted on the atmospheres of stars spurred investigations that eventually led to the synthesis of a new class of molecules on Earth. In the mid-1980s Harold Kroto, Richard Smalley, and Robert Curl (and their graduate students!) synthesized buckminsterfullerene (aka Bucky Balls), a soccer ball shaped molecule made of 60 carbon atoms. The researchers were awarded the Nobel Prize in 1996 for their discovery, which is credited with starting the field of nanotechnology.

Recently a NASA space probe returned to Earth after collecting atoms and ions from the solar wind. It is hoped that studies conducted on the ratio of isotopes would help give a better understanding of the nuclear reactions occurring in the sun.

Currently there is much effort directed to searching for simple organic molecules. These are detected and studied using a type of spectroscopy that examines electromagnetic radiation in the microwave range (the same type of electromagnetic radiation at work in a household microwave). In fact, as of 2001 astronomers had identified over 100 molecular species in deep space and there are probably tens of more detected since.

Below are links and references that you might find useful. Hope this helps!

http://antwrp.gsfc.nasa.gov/apod/ap010120.html

http://nobelprize.org/chemistry/laureates/1996/press.html

http://genesismission.jpl.nasa.gov/

Dickens J E; Irvine W M; Nummelin A; Mollendal H; Saito S; Thorwirth S; Hjalmarson A; Ohishi M. Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal. Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy (2001 Mar 15), 57(4), 643-60.

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