FYFD

Tag: astrophysics

  • “Orion, the Horsehead and the Flame in H-alpha”

    “Orion, the Horsehead and the Flame in H-alpha”

    Photographer Daniele Borsari captured this gorgeous composite image of nebulas in black and white, emphasizing the motion underlying the gas and dust. In the upper right, the Orion Nebula shines, bright with new stars. In the lower left, you can pick out the distinctive shape of the Horsehead Nebula and, further to the left, the Flame Nebula. We often see nebulas in bright colors, but I love the way black and white highlights the turbulence surrounding them. (Image credit: D. Borsari/ZWOAPOTY; via Colossal)

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  • Double Detonation in Type 1a Supernovae

    Double Detonation in Type 1a Supernovae

    Type 1a supernovae are agreed to be explosions of white dwarf stars, the remains of stars similar in mass to our Sun. They’re thought to be triggered when extra mass — from a nearby companion star, for example — triggers a runaway fusion reaction in their carbon and oxygen, elements that white dwarfs generally don’t have enough mass to successfully fuse. The runaway fusion then blows the star apart.

    But there’s another theory — demonstrated through numerical simulations — that suggests an alternate mechanism: a small explosion on the star’s surface could compress the interior enough to trigger fusion of the heavier elements there, thereby triggering a second detonation. The two explosions would happen in quick succession, making them difficult to detect, but astronomers predicted that each explosion could create a shell of calcium; given enough time, those two shells could drift apart, allowing astronomers to see a shell of sulfur between them.

    The team looked to a supernova remnant about 300 years old, and using a spectrograph from the Very Large Telescope, they were able to image — as predicted — a two shells of calcium, separated by sulfur, supporting the double-detonation hypothesis.

    The impact of double-detonation in Type 1a supernovae could be far-reaching. Right now, the intensity of these objects seems to be consistent enough that astronomers use their brightness to estimate their distance. Over the years, those distance estimates have been used to measure the universe’s expansion and provide evidence for the existence of dark matter. But if Type 1a supernovae are not all the same intensity, we may need to reevaluate their use as a universal yardstick. (Image credit: ESO/P. Das et al.; research credit: P. Das et al.; via Ars Technica)

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  • Veil Nebula

    Veil Nebula

    These glowing wisps are the visible remains of a star that went supernova about 7,000 years ago. Today the supernova remnant is known as the Veil Nebula and is visible only through telescopes. In the image, red marks hydrogen gas and blue marks oxygen. First carried by shock waves, these remains of a former star now serve as seed material for other stars and planetary systems to form. (Image credit: A. Alharbi; via APOD)

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  • Featured Video Play Icon

    See the Solar Wind

    After a solar prominence erupts, strong solar winds flow outward from the sun, carrying energetic particles that can disrupt satellites and trigger auroras if they make their way toward us. In this video, an instrument onboard the ESA/NASA’s Solar Orbiter captures the solar wind in the aftermath of such an eruption. The features seen here extended 3 solar radii and lasted for hours. The measurements give astrophysicists their best view yet of this post-eruption relaxation period, and the authors report that their measurements are remarkably similar to results of recent magnetohydrodynamics simulations, suggesting that those simulations are accurately capturing solar physics. (Video and image credit: ESA; research credit: P. Romano et al.; via Gizmodo)

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  • Stunning Interstellar Turbulence

    Stunning Interstellar Turbulence

    The space between stars, known as the interstellar medium, may be sparse, but it is far from empty. Gas, dust, and plasma in this region forms compressible magnetized turbulence, with some pockets moving supersonically and others moving slower than sound. The flows here influence how stars form, how cosmic rays spread, and where metals and other planetary building blocks wind up. To better understand the physics of this region, researchers built a numerical simulation with over 1,000 billion grid points, creating an unprecedentedly detailed picture of this turbulence.

    The images above are two-dimensional slices from the full 3D simulation. The upper image shows the current density while the lower one shows mass density. On the right side of the images, magnetic field lines are superimposed in white. The results are gorgeous. Can you imagine a fly-through video? (Image and research credit: J. Beattie et al.; via Gizmodo)

  • Cat’s Eye Halo

    Cat’s Eye Halo

    The Cat’s Eye Nebula is a planetary nebula located in the Draco constellation. At its center is a dying star. Seen here is the faint halo that stretches 3 light-years around the central nebula. The filaments of the halo are estimated to be 50,000 to 90,000 years old and were shed during earlier periods in the star’s evolution. Their shape is reminiscent of Rayleigh-Taylor instabilities, to my eye. (Image credit: T. Niittee; via APOD)

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  • Interstellar Jets

    Interstellar Jets

    This JWST image shows a couple of Herbig-Hero objects, seen in infrared. These bright objects form when jets of fast-moving energetic particles are expelled from the poles of a newborn star. Those particles hit pockets of gas and dust, forming glowing, hot shock waves like those seen here in red. The star that birthed the object is out of view to the lower-right. The bright blue light surrounded by red spirals that sits near the tip of the shock waves is actually a distant spiral galaxy that happens to be aligned with our viewpoint. (Image credit: NASA/ESA/CSA/STScI/JWST; via APOD)

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  • Jets, Shocks, and a Windblown Cavity

    Jets, Shocks, and a Windblown Cavity

    As material collapses onto a protostar, these young stars often form stellar jets that point outward along their axis of rotation. Made up of plasma, these jets shoot into the surrounding material, their interactions creating bright parabolic cavities like the one seen here. This is half of LDN 1471; the protostar’s other jet and cavity are hidden by dust but presumably mirror the bright shape seen here. (The protostar itself is the bright spot at the parabola’s peak.) Although the cavity is visibly striated, it’s not currently known what causes this feature. Perhaps some form of magnetohydrodynamic instability? (Image credit: NASA/Hubble/ESA/J. Schmidt; via APOD)

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  • The Best of FYFD 2024

    The Best of FYFD 2024

    Welcome to another year and another look back at FYFD’s most popular posts. (You can find previous editions, too, for 2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015, and 2014. Whew, that’s a lot!) Here are some of 2024’s most popular topics:

    This year’s topics are a good mix: fundamental research, civil engineering applications, geophysics, astrophysics, art, and one good old-fashioned brain teaser. Interested in what 2025 will hold? There are lots of ways to follow along so that you don’t miss a post.

    And if you enjoy FYFD, please remember that it’s a reader-supported website. I don’t run ads, and it’s been years since my last sponsored post. You can help support the site by becoming a patron, buying some merch, or simply by sharing on social media. And if you find yourself struggling to remember to check the website, remember you can get FYFD in your inbox every two weeks with our newsletter. Happy New Year!

    (Image credits: dam – Practical Engineering, ants – C. Chen et al., supernova – NOIRLab, sprinkler – K. Wang et al., wave tank – L-P. Euvé et al., “Dew Point” – L. Clark, paint – M. Huisman et al., iceberg – D. Fox, flame trough – S. Mould, sign – B. Willen, comet – S. Li, light pillars – N. Liao, chair – MIT News, Faraday instability – G. Louis et al., prominence – A. Vanoni)

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  • A Shallow Origin for the Sun’s Magnetic Field

    A Shallow Origin for the Sun’s Magnetic Field

    The Sun‘s complex magnetic field drives its 11-year solar activity cycle in ways we have yet to understand. During active periods, more sunspots appear, along with roiling flows within the Sun that scientists track through helioseismology. Longstanding theories posit that the Sun’s magnetic field has a deep origin, about 210,000 kilometers below the surface. But new measurements have prompted an alternate theory: that the Sun’s magnetic field originates in its outer 5-10% due to a magnetorotational instability.

    Magnetorotational instabilities are usually associated with the accretion disks around black holes and other massive objects. When an electrically-conductive fluid — like the Sun’s plasma — is rotating, even a small deviation in its path can get magnified by a magnetic field. In accretion disks, these little disruptions grow until the disk becomes turbulent.

    By applying this idea to the sun, researchers found they were better able to match measurements of the plasma flows beneath the Sun’s surface. With measurements from future heliophysics missions, they believe they can work out the mechanisms driving sunspot formation, which would help us better predict solar storms that can damage electronics here on Earth. (Image credit: NASA/SDO/AIA/LMSAL; research credit: G. Vasil et al.; via Physics World)