Hot Water from Outer Space

You’re not in hot water.  Water that used to be very hot is in you… water from the cold depths of Interstellar Space.

Let me ask you a question.  Don’t say anything, just think of the answer.  What is the formula for water?

Wrong.  Water is not H2O.  To be more accurate, water is not only H2O.  A glass of water is a complicated and always changing mixture of H2O… that molecule, but missing one hydrogen and with a negative electric charge (HO-, called a hydroxyl ion); that molecule with an extra hydrogen and a positive electric charge (H3O+, called a hydronium ion); that molecule with an extra oxygen (H2O2, called  Hydrogen Peroxide), and dozens of other molecules and ions through H5O5, and beyond.  But where did it come from?

Scientists believe that many, maybe most of the water in your body, and in every other living thing on Earth, in the oceans, the seas, the rivers, the lakes, and each drop of rain came from comets that long ago bombarded our planet.

And what is a comet?  Ice and dust. This was first understood by Fred Lawrence Whipple, an American astronomer who worked at the Harvard College Observatory for over 70 years. I heard of him when I was a little boy, and so I also wanted to be an astronomer.  I heard about him from my father, who had taken his one and only Astronomy course from professor Whipple at Harvard. Whipple discovered some asteroids and comets, and invented the “dirty snowball” comet hypothesis.  His 1927 degree from UCLA was in mathematics.  In a 1978 biography, Whipple wrote that the “mathematics major veered [me] through physics and finally focused on astronomy where time, space, mathematics, and physics had a common meeting ground.”

But let’s ask the next question.  Where did the water in comets come from?  Did it start out as steam, water vapor, or ice?  A scientific result announced this week [“Hot Water in Cold Comets: Water Around Comets Produced With Unusual Properties”] has a surprising answer. The details of the experimental study, performed by an  international research team led by Andreas Wolf of the Max-Planck Institute for Nuclear Physics in Heidelberg, Germany, was published in the journal Physical Review Letters. They didn’t use a telescope for this experiment.  They used a Heidelberg Test Storage Ring, part of what is colloquially called “an atom smasher.”

The conclusion? Water molecules produced under cold, dilute conditions in the space between the stars began as particles as hot as 60,000 Kelvin, 60,000 degrees Centigrade above absolute zero.

Which brings us back around. You’re not in hot water.  Water that used to be very hot is in you… water from the cold depths of Interstellar Space… water that started hotter than fire, and collected into dirty snowballs, which smashed into earth long before you were born.

Is the glass of water half empty or half full? It is loaded with a hot story so strange that that it might send chills down your spine.


Whipple, Fred L. (1978). “The Earth as part of the Universe” Annual Review of Earth and Planetary Sciences 6: 1–9. doi:10.1146/annurev.ea.06.050178.000245.

H. Buhr, J. Stützel, M. Mendes, O. Novotný, D. Schwalm, M. Berg, D. Bing, M. Grieser, O. Heber, C. Krantz, S. Menk, S. Novotny, D. Orlov, A. Petrignani, M. Rappaport, R. Repnow, D. Zajfman, A. Wolf. Hot Water Molecules from Dissociative Recombination of D3O+ with Cold Electrons. Physical Review Letters, 2010; 105 (10): 103202 DOI: 10.1103/PhysRevLett.105.103202


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