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Journeywork of the Stars

Radioactive elements found in the cores of planets may determine which worlds might host living species

Scientific American  February 2021

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In his monumental series Cosmos, astronomer Carl Sagan famously said that we humans are “made of star stuff.” Dying stars are continually filling the universe with heavy elements, and the energy of the cosmos sparked life into existence on this planet. After billions of years, plants began to harvest sunlight directly, converting solar into chemical energy, and therefore all human life feeds on the output of stars. Those same elements that streamed through the vacuum of space and coalesced in the core of Earth also, it seems, created the conditions under which life can survive.

As writer Marcus Woo details in this issue’s cover story, certain radionuclides in exoplanets may be the signal to look for if we want to find alien life (see “Stellar Smashups May Fuel Planetary Habitability, Study Suggests”). An exciting potential extraterrestrial signal radiated to Earth last December, causing a media stir, as do all prospects of meeting our cosmic neighbors (see “Alien Hunters Discover Mysterious Signal from Proxima Centauri”). Indeed, if we find intelligent life in the universe, we will have a common heritage.

Andrea Gawrylewski is chief newsletter editor at Scientific American. She writes the daily Today in Science newsletter and oversees all other newsletters at the magazine. In addition, she manages all special editions and in the past was the editor for Scientific American Mind, Scientific American Space & Physics and Scientific American Health & Medicine. Gawrylewski got her start in journalism at the Scientist magazine, where she was a features writer and editor for "hot" research papers in the life sciences. She spent more than six years in educational publishing, editing books for higher education in biology, environmental science and nutrition. She holds a master's degree in earth science and a master's degree in journalism, both from Columbia University, home of the Pulitzer Prize.

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SA Space & Physics Vol 4 Issue 1This article was published with the title “Journeywork of the Stars” in SA Space & Physics Vol. 4 No. 1 ()
doi:10.1038/scientificamerican022021-5JqlEQJdatDYQs1eqaGJP1

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