Study: Comets Did Not Supply Earth's Water

Slightly different versions of water's constituent elements, hydrogen and oxygen, are relatively common in the universe. But how did Earth's version of water get here? European Space Agency astronomers have been looking for clues using their Rosetta spacecraft to inspect Comet 67P/Churyumov-Gerasimenko.

Earlier this year, Rosetta orbited the comet while analyzing the gas the comet continually ejects. The findings show that the comet's water differs significantly from water on Earth.

A research team published details of their discovery in Science, noting that the comet's water molecules have about three times more deuterium than hydrogen.1 Deuterium is a heavy but stable isotope of hydrogen. It carries a proton and neutron in its nucleus, whereas the more abundant version of hydrogen carries just one proton.

If comets supplied the water to form Earth's oceans, then the ratio of deuterium to common hydrogen should be about the same, not three times higher in comets. Perhaps this comet's water does not represent water found in other comets—but that would throw a new kink in the secular notion that comets and Earth all formed from the same material.

Secularists, who by definition only consider natural sources of water when they reconstruct our home planet's origin, have long envisioned that—billions of years ago—a substantial torrent of comet impacts built Earth's oceans. This new evidence derails that old picture.

Kathryn Altwegg is the principal investigator on the project. She told BBC Radio, "It is the highest-ever measured ratio of heavy water relative to light water in the Solar System. It is more than three times higher than on the Earth, which means that this kind of comet could not have brought water to the Earth."2

If they can no longer assert that Earth's water was donated by fortuitous collisions of ancient, water-rich comets, then where else could the water have come from? The Science study authors suggested that asteroids would be the next place to look.

However, the heat resulting from either comet or asteroid collisions should have vaporized whatever water they had, sending it back out into space eons ago—supposedly back when Earth's atmosphere was not yet fully developed. Since secularists imagine that Earth formed from a molten mass that was too hot for water, their options for Earth water's origins are vaporizing.

Removing secularism reveals the possibility that water came not from a natural source, but from a supernatural one. Scripture is explicit, both in Genesis 1 and 2 Peter 3, that God formed Earth by water, not a molten mass. This would explain the otherwise muggy mystery of why Earth has so much wonderful and unique water.3


  1. Altwegg, K. et al. 67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio. Science. Published online before print, December 10, 2014. DOI: 10.1126/science.1261952.
  2. Water on Comets; DNA in Space; Sounds of the Ocean; Science in Fashion. BBC Inside Science. Posted on December 11, 2014, accessed December 16, 2014.
  3. Maybe that same Creator placed over three times more deuterium in Comet 67P/Churyumov-Gerasimenko's water than in Earth's water just to point toward Himself as the answer to ultimate origins. See Thomas, B. European Spacecraft's Comet Close-up a World First. Creation Science Update. Posted on August 13, 2014, accessed December 16, 2014.

Image credit: ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0 Adapted for use in accordance with federal copyright (fair use doctrine) law. Usage by ICR does not imply endorsement of copyright holders.

* Mr. Thomas is Science Writer at the Institute for Creation Research.

Article posted on December 29, 2014.

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