Of all species that have existed on Earth, 99.9 percent are now extinct. Many of them perished in five cataclysmic events. The classical "Big Five" mass extinctions identified by Raup and Sepkoski are widely agreed upon as some of the most significant: End Ordovician, Late Devonian, End Permian, End Triassic, and End Cretaceous. According to a recent poll, seven out of ten biologists think we are currently in the throes of a sixth mass extinction. Some say it could wipe out as many as 90 percent of all species living today. Other scientists dispute such dire projections.
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"Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to the early Earth, thereby fueling the emergence of life,” said Michael Mumma, director of the Goddard Center for Astrobiology. New observations and research from Chile's ALMA Observatory open a new window on this poorly known component of cometary organics.
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Scientists hunting for life beyond Earth have discovered more than 1,800 planets outside our solar system, or exoplanets, in recent years, but so far, no one has been able to confirm an exomoon. Now, physicists from The University of Texas at Arlington believe following a trail of radio wave emissions may lead them to that discovery. Their recent findings describe radio wave emissions that result from the interaction between Jupiter’s magnetic field and its moon Io (image above). They suggest using detailed calculations about the Jupiter/Io dynamic to look for radio emissions that could indicate moons orbiting an exoplanet.
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Just over a month after launch, the Orbiting Carbon Observatory-2 (OCO-2) -- NASA's first spacecraft dedicated to studying atmospheric carbon dioxide -- has maneuvered into its final operating orbit and produced its first science data. Atmospheric carbon dioxide is the leading human-produced greenhouse gas responsible for warming our world. It is a critical natural component of Earth's carbon cycle. NASA's Orbiting Carbon Observatory-2 (OCO-2) will produce the most detailed picture to date of sources of carbon dioxide, as well as their natural "sinks" -- places on Earth's surface where carbon dioxide is removed from the atmosphere. The observatory will study how these sources and sinks are distributed around the globe and how they change over time.
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At the ends of the Universe there are black holes with masses equaling billions of our sun. These giant bodies – quasars – feed on interstellar gas, swallowing large quantities of it non-stop. Thus they reveal their existence: The light that is emitted by the gas as it is sucked in and crushed by the black hole's gravity travels for eons across the Universe until it reaches our telescopes. Looking at the edges of the Universe is therefore looking into the past. These far-off, ancient quasars appear to us in their infancy, taken less than a billion years after the Big Bang. Since these ancient quasars were first discovered, scientists have wondered what process could lead a small black hole to gorge and fatten to such an extent, so soon after the Big Bang.
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The image above is a composite of data from NASA's Chandra X-ray Observatory and the Hubble Space Telescope. The object seen at the center is an "ultraluminous X-ray source" (ULX) in a globular cluster belonging to an elliptical galaxy in the constellation of Fornax. Researchers suspect that the ULX represents a white dwarf star being destroyed an intermediate-mass black hole in the globular cluster.
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What we perceive as the big bang, physicists at the Perimeter Institure argue, could be the three-dimensional “mirage” of a collapsing star in a universe profoundly different than our own. Conventional understanding holds that the big bang began with a singularity – an unfathomably hot and dense phenomenon of spacetime where the standard laws of physics break down. Singularities are bizarre, and our understanding of them is limited.
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“Rotation can have a huge effect, and lots of planets that we previously thought were definitely not habitable now can be considered as candidates,” says Dorian Abbot of the University of Chicago. New research has revealed that the rate at which a planet spins is instrumental in its ability to support life. Not only does rotation control the length of day and night, it can also tug on the winds that blow through the atmosphere and ultimately influence cloud formation.
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NASA's Cassini spacecraft will execute the largest planned maneuver of the spacecraft's remaining mission on Saturday, Aug. 9. The maneuver will target Cassini toward an Aug. 21 encounter with Saturn's largest moon, Titan.
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An international team of researchers has found extremely small habitats that increase the potential for life on other planets and moons such as Jupiter's Io and Saturn's Titan, while offering a way to clean up oil spills on our own. Looking at samples from Earth's largest natural asphalt lake, they found active microbes in droplets as small as a microliter, which is about 1/50th of a drop of water.
"We saw a huge diversity of bacteria and archaea," said Dirk Schulze-Makuch, a professor in Washington State University's School of the Environment and the only U.S. researcher on the team. "That's why we speak of an 'ecosystem,' because we have so much diversity in the water droplets."
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