10/26/2023 0 Comments Comet deep ocean wavesOr all of the above! The origin of Earth's oceans remains a mystery, a topic for continued research. Our oceans may have been delivered by asteroids (another controversial idea) or perhaps water was caught up in the body of Earth as it formed and later released by volcanic outgassing (as many of us learned in school). But do they? Comets aren't the only candidate water sources for Earth. Now Comet LINEAR has shown us that Earth's oceans could hail from comets after all. Instead, it was delivered in kit form from space."Įditor's Note: In 1999 cosmochemist Geoff Blake and colleagues at Caltech showed that Comet Hale-Bopp contained too much heavy water to match Earth's oceans.Those findings triggered widespread reports that comets couldn't be a source of terrestrial water. This means life on Earth did not have to start completely from scratch. Such comets would have had a greater portion of life's building blocks - the complex organic molecules - to begin with. "The smaller comets from Jupiter's region impacted Earth relatively gently, shattering high in the atmosphere and delivering most of their organic molecules intact. "It's like being hit by a snowball instead of an iceberg," said Mumma. Right: Comets born near Jupiter may contain the right flavor of water to explain Earth's oceans. Both factors may have given a boost to life on Earth. Also, Jupiter's powerful gravity kept collision speeds between comets near it high, preventing them from growing very large. As a result, more reactions occurred in the gas near Jupiter and greater amounts of many complex organic molecules were available to wind up in comets. The "Jupiter zone" received more light and was warmer than the outer solar system. Astronomers think the primordial Earth would have intercepted more comets from the "Jupiter zone" (which is comparatively poor in heavy water) than ones that formed in the outer solar system (which is rich in heavy water). Nevertheless, they would have been numerous during the solar system's formative years. Unfortunately, Comet LINEAR broke up before this could be directly confirmed, but its low concentration of volatile organic molecules provides a strong indication that it carried the same kind of water that fills terrestrial seas.Ĭomets born near Jupiter are rare today because the giant planet's gravity long ago flung most of them into interstellar space. Īccording to some laboratory experiments, a comet born billions of years ago ago in the neighborhood of Jupiter would contain about the same fraction of heavy water as Earth's present-day oceans. Left: The Solar Wind ANisotropies (SWAN) experiment on board the Solar and Heliospheric Observatory spotted a cloud of hydrogen swirling around Comet LINEAR - a byproduct of cometary water split by solar radiation into O and H. Science & Astronomy If an Asteroid Hits the Ocean, Does It Make a Tsunami (Probably Not) By Ian O'Neill published 19 December 2016 (Image credit: LANL) Fifteen years ago, Galen Gisler had a gut. Comets that formed nearer the Sun (where those substances remain in gaseous form) would contain fewer volatiles. Comets that formed in the outer solar system (where it is very, very cold) would include such frozen molecules in their icy nuclei. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday.Chemistry tells astronomers where a comet formed in the following way: Certain molecules like carbon monoxide (CO), methane (CH4), ethane (C2H6), and acetylene (C2H2) are "volatile." They freeze only at extremely low temperatures. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015 her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Her latest book, " Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, working inside a spacesuit, and participating in a simulated Mars mission. She was contributing writer for for 10 years before joining full-time. Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |