Recent Comments

    Category Astronomy/Space

    Microwave Imaging of Quasi-Periodic Pulsations at Flare Current Sheet

    January 5, 2023, Categories  Astronomy/Space

     Microwave emissions from the flare. The upper group is from flaring loops, and the lower group extends along reconnection current sheet. The background is an EUV image at 211 A. The gold curve represents the temporal variation curve of current sheet source at 8.4 GHz.

    Quasi-periodic pulsations (QPPs; also known as quasi-periodic oscillations, i.e., QPOs) are electromagnetic emission phenomena that vary quasi-periodically with time. They appear in celestial transient events with different temporal/spatial scales, such as stellar flares, gamma ray bursts and fast radio bursts.

    The sun, an ordinary star closest to us, is a place where flares with QPPs appear frequently...

    Read More

    Hubble finds that Ghost Light among Galaxies Stretches Far Back in Time

    January 5, 2023, Categories  Astronomy/Space

    These are Hubble Space Telescope images of two massive clusters of galaxies named MOO J1014+0038 (left panel) and SPT-CL J2106-5844 (right panel). The artificially added blue color is translated from Hubble data that captured a phenomenon called intracluster light. This extremely faint glow traces a smooth distribution of light from wandering stars scattered across the cluster. Billions of years ago the stars were shed from their parent galaxies and now drift through intergalactic space.
    Credits: NASA, ESA, STScI, James Jee (Yonsei University); Image Processing: Joseph DePasquale (STScI)

    In giant clusters of hundreds or thousands of galaxies, innumerable stars wander among the galaxies like lost souls, emitting a ghostly haze of light...

    Read More

    A Step Towards Solar Fuels out of Thin Air

    January 5, 2023, Categories  Astronomy/Space

    © 2023 EPFL / Alain Herzog : Kevin Sivula and his team invented a solar-powered artificial leaf for harvesting hydrogen fuel from humid air.
    EPFL chemical engineers have invented a solar-powered artificial leaf, built on a novel electrode which is transparent and porous, capable of harvesting water from the air for conversion into hydrogen fuel. The semiconductor-based technology is scalable and easy to prepare.

    A device that can harvest water from the air and provide hydrogen fuel — entirely powered by solar energy — has been a dream for researchers for decades. Now, EPFL chemical engineer Kevin Sivula and his team have made a significant step towards bringing this vision closer to reality...

    Read More

    Are Black Holes Time Machines? Yes, but there’s a Catch

    January 5, 2023, Categories  Astronomy/Space

    Are black holes time machines? Yes, but there's a catch
    Credit: NASA / Goddard Space Flight Center / Jeremy Schnittman

    Black holes form natural time machines that allow travel to both the past and the future. But don’t expect to be heading back to visit the dinosaurs any time soon.

    At present, we don’t have spacecraft that could get us anywhere near a black hole. But, even leaving that small detail aside, attempting to travel into the past using a black hole might be the last thing you ever do.

    What are black holes?

    A black hole is an extremely massive object that is typically formed when a dying star collapses in on itself.

    Like planets and stars, black holes have gravitational fields around them. A gravitational field is what keeps us stuck to Earth, and what keeps Earth revolving around the Sun.

    As a rule of thumb, the mor...

    Read More