![]() ![]() Jesse Bloom, a viral evolutionary geneticist at the Fred Hutchinson Cancer Research Center in Seattle, Washington, discovered the sequences after searching for genomic data from the pandemic’s early stages. The sequences address an evolutionary conundrum about the early genetic diversity of the coronavirus SARS-CoV-2. Credit: Zhao Jun/VCG/Getty Deleted coronavirus sequences trigger scientific intrigueĪ biologist in the United States has ‘excavated’ partial SARS‑CoV-2 genome sequences from the beginnings of the pandemic’s probable epicentre in Wuhan, China, that were deposited - but later removed - from a US government database. SARS-2-CoV testing in Wuhan, China, where the first cases of COVID-19 were reported. The method assumed for spying Earth from elsewhere in the Galaxy is the same as that used by astronomers to discover thousands of exoplanets: detecting the light of a star dimming slightly as a planet passes across its face. Seven of the 2,034 are already known to host planets - but many more are likely to have worlds orbiting them. ![]() ![]() Of those, 1,715 are in the right locations to have spotted Earth so far, and another 319 will have vantage points in the future (see ‘All eyes on Earth’). Of more than 330,000 stars in the Gaia catalogue that are within 100 parsecs of Earth, just 2,034 happen to have the required viewing geometry. ![]() The discovery was made possible by the European Space Agency’s Gaia space observatory, which has compiled the best 3D map of stars so far. In doing so, the study expands astronomers’ thinking about which stars have “a better-than-average shot of discovering and characterizing the Earth”, says Sofia Sheikh, an astrobiologist at the Berkeley SETI Research Center in California. With this information, the scientists were able to predict from where Earth was visible over the past 5,000 years or so of human civilization - and from where it will be visible up to 5,000 years into the future. Those aliens would be the natural choice for Earthlings to look for, say the scientists - because they could have already had a chance to spot us, and thus might be primed to receive communications from Earth.Īlthough previous studies have considered this question, this is the first to incorporate the movement of stars as they slide in or out of the narrow slice of the sky that lines up with both Earth and the Sun. “For whom would we be the aliens?” she asks. The work offers a new way of thinking about the search for extraterrestrial life, says Lisa Kaltenegger, an astronomer at Cornell University in Ithaca, New York, who led the analysis. If there are aliens on planets around those stars with at least a similar level of technological advancement to ours, then they would theoretically be able to spot us ( L. Credit: OpenSpace/American Museum of Natural History Aliens would glimpse Earth from these 2,000 starsĪstronomers have pinpointed 2,034 stars from which, in the not-too-distant past or future, Earth could be detected transiting the face of the Sun. Stars with a past or future view of Earth as a transiting exoplanet appear brightened. An illustration of Earth from space illuminated by the Sun. ![]()
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