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    Category Astronomy/Space

    MACHOs are dead, WIMPs are a no-show – say hello to SIMPs

    December 5, 2017, Categories  Astronomy/Space

    Conventional WIMP theories predict that dark matter particles rarely interact with one another, and only weakly with normal matter. Hitoshi Murayama of UC Berkeley and Yonit Hochberg of Hebrew University predict that dark matter SIMPs, comprised of a quark and an antiquark, would collide and interact strongly with one another, producing noticeable effects when the dark matter in galaxies collide. Credit: Kavli IPMU graphic

    Conventional WIMP theories predict that dark matter particles rarely interact with one another, and only weakly with normal matter. Hitoshi Murayama of UC Berkeley and Yonit Hochberg of Hebrew University predict that dark matter SIMPs, comprised of a quark and an antiquark, would collide and interact strongly with one another, producing noticeable effects when the dark matter in galaxies collide. Credit: Kavli IPMU graphic

    Colliding galaxies may be evidence in support of new candidate for universe’s elusive dark matter. The nature of dark matter remains elusive, with numerous experimental searches for WIMPs coming up empty-handed and MACHOs all but abandoned...

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    Neutron Stars on the Brink of Collapse

    December 5, 2017, Categories  Astronomy/Space

    The upper and lower series of pictures each show a simulation of a neutron star merger. In the scenario shown in the upper panels the star collapses after the merger and forms a black hole, whereas the scenario displayed in the lower row leads to an at least temporarily stable star. Credit: Andreas Bauswein, HITS

    The upper and lower series of pictures each show a simulation of a neutron star merger. In the scenario shown in the upper panels the star collapses after the merger and forms a black hole, whereas the scenario displayed in the lower row leads to an at least temporarily stable star. Credit: Andreas Bauswein, HITS

    Scientists have managed to narrow down the size of neutron stars with the aid of computer simulations. The calculations based on data from the LIGO and Virgo observatories suggest that the neutron star radius must be at least 10.7 km. When a very massive star dies, its core contracts. In a supernova explosion, the star’s outer layers are expelled, leaving behind an ultra-compact neutron star...

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    Astronomer’s Map reveals Location of Mysterious Fast-moving Gas

    December 4, 2017, Categories  Astronomy/Space

    An all-sky map showing the radial velocity of neutral hydrogen gas belonging to the high-velocity clouds of the Milky Way and two neighboring galaxies, the Large and Small Magellanic Clouds. Credit: ICRAR

    An all-sky map showing the radial velocity of neutral hydrogen gas belonging to the high-velocity clouds of the Milky Way and two neighboring galaxies, the Large and Small Magellanic Clouds. Credit: ICRAR

    An Australian scientist has created the most detailed map ever of clouds of high-velocity gas in the Universe around us. The map covers the entire sky and shows curious clouds of neutral hydrogen gas that are moving at a different speed to the normal rotation of the Milky Way. It was created by astronomer Dr Tobias Westmeier, University of Western Australia node of the International Centre for Radio Astronomy Research, and published in the leading journal Monthly Notices of the Royal Astronomical Society.

    Dr Westmeier said the map suggests that at least 13% of the sky is covered by high-v...

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    Turbulence in Astrophysical Plasmas

    December 4, 2017, Categories  Astronomy/Space

    Magnetic reconnection is a complicated phenomenon that Nuno Loureiro, an associate professor of nuclear science and engineering and of physics at MIT, has been studying in detail for more than a decade. To explain the process, he gives a well-studied example: “If you watch a video of a solar flare” as it arches outward and then collapses back onto the sun’s surface, “that’s magnetic reconnection in action. It’s something that happens on the surface of the sun that leads to explosive releases of energy.” Loureiro’s understanding of this process of magnetic reconnection has provided the basis for the new analysis that can now explain some aspects of turbulence in plasmas. Credit: NASA

    Magnetic reconnection is a complicated phenomenon that Nuno Loureiro, an associate professor of nuclear science and engineering and of physics at MIT, has been studying in detail for more than a decade. To explain the process, he gives a well-studied example: “If you watch a video of a solar flare” as it arches outward and then collapses back onto the sun’s surface, “that’s magnetic reconnection in action. It’s something that happens on the surface of the sun that leads to explosive releases of energy.” Loureiro’s understanding of this process of magnetic reconnection has provided the basis for the new analysis that can now explain some aspects of turbulence in plasmas. Credit: NASA

    Theoretical analysis uncovers new mechanisms in plasma turbulence...

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