• Scientists identify 29 planets where aliens could observe Earth | Astronomy | The Guardian
    https://www.theguardian.com/science/2021/jun/23/scientists-identify-29-planets-where-aliens-could-observe-earth

    The scientists identified 1,715 star systems in our cosmic neighbourhood where alien observers could have discovered Earth in the past 5,000 years by watching it “transit” across the face of the sun.

    Among those in the right position to observe an Earth transit, 46 star systems are close enough for their planets to intercept a clear signal of human existence – the radio and TV broadcasts which started about 100 years ago.

    The researchers estimate that 29 potentially habitable planets are well positioned to witness an Earth transit, and eavesdrop on human radio and television transmissions, allowing any observers to infer perhaps a modicum of intelligence. Whether the broadcasts would compel an advanced civilisation to make contact is a moot point.

    “One way we find planets is if they block out part of the light from their host star,” said Lisa Kaltenegger, professor of astronomy and director of the Carl Sagan Institute at Cornell University in New York. “We asked, ‘Who would we be the aliens for if somebody else was looking?’ There is this tiny sliver in the sky where other star systems have a cosmic front seat to find Earth as a transiting planet.”

    Earthly astronomers have detected thousands of planets beyond the solar system. About 70% are spotted when alien worlds pass in front of their host stars and block some of the light that reaches scientists’ telescopes. Future observatories, such as Nasa’s James Webb Space Telescope due to launch this year, will look for signs of life on “exoplanets” by analysing the composition of their atmospheres.

    To work out which nearby star systems are well placed to observe an Earth transit, Kaltenegger and Dr Jackie Faherty, an astrophysicist at the American Museum of Natural History, turned to the European Space Agency’s Gaia catalogue of star positions and motions. From this they identified 2,034 star systems within 100 parsecs (326 light years) that could spot an Earth transit any time from 5,000 years ago to 5,000 years in the future.

  • Tiny traces of DNA found in cave dust may unlock secret life of Neanderthals | Archaeology | The Guardian
    https://www.theguardian.com/science/2021/may/16/tiny-traces-of-dna-found-in-cave-dust-may-unlock-secret-life-of-neander

    The discovery is the first important demonstration of a powerful new technique that allows researchers to study DNA recovered from cave sediments. No fossils or stone tools are needed for such studies. Instead, minuscule traces of genetic material that have accumulated in the dust of a cavern floor are employed to reveal ancient secrets.“The potential of this technology is fantastic,” said Professor Chris Stringer of the Natural History Museum, London.
    (...)
    “You don’t need to have a stone tool or a fossil bone to find out if an ancient human had lived or worked at a site. All you need is the DNA that they left behind in the debris of their cave homes. That has enormous implications for all sorts of investigations.”
    (...)
    “Galería de las Estatuas is a well-studied cave in which we have clear evidence of Neanderthals having lived there for tens of thousands of years,” said Max Planck researcher Benjamin Vernot, who led the investigation. “We don’t think they buried their dead there but we do believe they may have butchered meat there. Occasionally, they would have cut themselves and would have bled on the cave floor. Similarly, their babies would have deposited excrement there and so left their DNA behind.”

  • US has ’moral imperative’ to develop AI weapons, says panel
    https://www.theguardian.com/science/2021/jan/26/us-has-moral-imperative-to-develop-ai-weapons-says-panel

    Draft Congress report claims AI will make fewer mistakes than humans and lead to reduced casualties The US should not agree to ban the use or development of autonomous weapons powered by artificial intelligence (AI) software, a government-appointed panel has said in a draft report for Congress. The panel, led by former Google chief executive Eric Schmidt, on Tuesday concluded two days of public discussion about how the world’s biggest military power should consider AI for national security (...)

    #Alphabet #Google #Microsoft #algorithme #robotique #éthique #militaire #arme

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