This supernova shock wave plows through interstellar space at over 500,000 kilometers per hour. Near the middle and moving up in this sharply detailed color composite, thin, bright, braided filaments are actually long ripples in a cosmic sheet of glowing gas seen almost edge-on. Cataloged as NGC 2736, its elongated appearance suggests its popular name, the Pencil Nebula. The Pencil Nebula is about 5 light-years long and 800 light-years away, but represents only a small part of the Vela supernova remnant. The Vela remnant itself is around 100 light-years in diameter, the expanding debris cloud of a star that was seen to explode about 11,000 years ago. Initially, the shock wave was moving at millions of kilometers per hour but has slowed considerably, sweeping up surrounding interstellar material. In the featured narrow-band, wide field image, red and blue colors track, primarily, the characteristic glows of ionized hydrogen and oxygen atoms, respectively.
What lights up the Flame Nebula? Fifteen hundred light years away towards the constellation of Orion lies a nebula which, from its glow and dark dust lanes, appears, on the left, like a billowing fire. But fire, the rapid acquisition of oxygen, is not what makes this Flame glow. Rather the bright star Alnitak, the easternmost star in the Belt of Orion visible on the far left, shines energetic light into the Flame that knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. The featured picture of the Flame Nebula (NGC 2024) was taken across three visible color bands with detail added by a long duration exposure taken in light emitted only by hydrogen. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.
What happens when two black holes collide? This extreme scenario occurs in the centers of many merging galaxies and multiple star systems. The featured video shows a computer animation of the final stages of such a merger, while highlighting the gravitational lensing effects that would appear on a background starfield. The black regions indicate the event horizons of the dynamic duo, while a surrounding ring of shifting background stars indicates the position of their combined Einstein ring. All background stars not only have images visible outside of this Einstein ring, but also have one or more companion images visible on the inside. Eventually the two black holes coalesce. The end stages of such a merger is now known to produce a strong blast of gravitational radiation, providing a new way to see our universe.
By comparing our local Comet Hale-Bopp to the interstellar visitor 2I/Borisov, a team of astronomers have concluded that the interloper is perhaps one of the most pristine comets we’ve ever seen.
“2I/Borisov could represent the first truly pristine comet ever observed,” says Stefano Bagnulo of the Armagh Observatory and Planetarium, Northern Ireland, UK, who led the new study published recently in Nature Communications.
Many comets pass at least once through the inner solar system in their lifetimes. When they do, they encounter the solar wind and any other random pieces of microscopic junk floating around. This contaminates them to such a degree that astronomers can determine how many passages a comet has made since it formed.
Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106. Modern deep telescopic views reveal it to be an island universe - a spiral galaxy around 30 thousand light-years across located only about 21 million light-years beyond the stars of the Milky Way. Along with a bright central core, this stunning galaxy portrait, a composite of image data from amateur and professional telescopes, highlights youthful blue star clusters and reddish stellar nurseries tracing the galaxy’s spiral arms. It also shows off remarkable reddish jets of glowing hydrogen gas. In addition to small companion galaxy NGC 4248 at bottom right, background galaxies can be found scattered throughout the frame. M106, also known as NGC 4258, is a nearby example of the Seyfert class of active galaxies, seen across the spectrum from radio to X-rays. Active galaxies are powered by matter falling into a massive central black hole.
No matter how it is cooked, the Olive Wagyu that’s harvested from a herd of 2,000 Kuroge-washu cattle that live on a small island in Japan’s Kagawa Prefecture and subsist on a diet that includes upcycled pulp taken from spent olives is very, very rare. Produced according to the concept of mottainai (basically the idea of recognizing the inherent value of resources and not wasting them), Olive Wagyu is highly coveted and nearly impossible to get stateside outside of special shipments.
Yesterday was like a good TV episode: high-speed action, plot twists, and a cliffhanger ending. We now know that the strength of the little magnet inside the muon is described by the g-factor:
g = 2.00233184122(82).
Any measurement of basic properties of matter is priceless, especially when it come with this incredible precision. But for a particle physicist the main source of excitement is that this result could herald the breakdown of the Standard Model. The point is that the g-factor or the magnetic moment of an elementary particle can be calculated theoretically to a very good accuracy. Last year, the white paper of the Muon g−2 Theory Initiative came up with the consensus value for the Standard Model prediction
g = 2.00233183620(86),
which is significantly smaller than the experimental value. The discrepancy is estimated at 4.2 sigma, assuming the theoretical error is Gaussian and combining the errors in quadrature.
As usual, when we see an experiment and the Standard Model disagree, these 3 things come to mind first
Flawed theory prediction.
The multicolor, stereo imaging Mastcam-Z on the Perseverance rover zoomed in to captured this 3D close-up (get out your red/blue glasses) of the Mars Ingenuity helicopter on mission sol 45, April 5. That’s only a few sols before the technology demonstrating Ingenuity will attempt to fly in the thin martian atmosphere, making the first powered flight on another planet. The historic test flight is planned for no earlier than Sunday, April 11. Casting its shadow on the martian surface, Ingenuity is standing alone on four landing legs next to the rover’s wheel tracks. The experimental helicopter’s solar panel, charging batteries that keep it warm through the cold martian nights and power its flight, sits above its two 1.2 meter (4 foot) long counter-rotating blades.
This paper explores the fundamental causal limits on how much of the universe we can observe or affect. It distinguishes four principal regions: the affectable universe, the observable universe, the eventually observable universe, and the ultimately observable universe. It then shows how these (and other) causal limits set physical bounds on what spacefaring civilisations could achieve over the longterm future.
Found in far southern skies, deep within the boundaries of the constellation Dorado, NGC 1947 is some 40 million light-years away. In silhouette against starlight, obscuring lanes of cosmic dust thread across the peculiar galaxy’s bright central regions. Unlike the rotation of stars, gas, and dust tracing the arms of spiral galaxies, the motions of dust and gas don’t follow the motions of stars in NGC 1947 though. Their more complicated disconnected motion suggest this galaxy’s visible threads of dust and gas may have come from a donor galaxy, accreted by NGC 1947 during the last 3 billion years or so of the peculiar galaxy’s evolution. With spiky foreground Milky Way stars and even more distant background galaxies scattered through the frame, this sharp Hubble image spans about 25,000 light-years near the center of NGC 1947.
Is this just a lonely tree on an empty hill? To start, perhaps, but look beyond. There, a busy universe may wait to be discovered. First, physically, to the left of the tree, is the planet Mars. The red planet, which is the new home to NASA’s Perseverance rover, remains visible this month at sunset above the western horizon. To the tree’s right is the Pleiades, a bright cluster of stars dominated by several bright blue stars. The featured picture is a composite of several separate foreground and background images taken within a few hours of each other, early last month, from the same location on Vinegar Hill in Milford, Nova Scotia, Canada. At that time, Mars was passing slowly, night after night, nearly in front of the distant Seven Sisters star cluster. The next time Mars will pass angularly as close to the Pleiades as it did in March will be in 2038.
Those patterns, visible in satellite images of the Red Planet’s south pole, aren’t real spiders, of course; but the branching, black shapes carved into the Martian surface look creepy enough that researchers dubbed them “araneiforms” (meaning “spider-like”) after discovering the shapes more than two decades ago.
Measuring up to 3,300 feet (1 kilometer) across, the gargantuan shapes don’t resemble anything on Earth. But in a new study published March 19 in the journal Scientific Reports, scientists successfully recreated a shrunken-down version of the spiders in their lab, using a slab of carbon dioxide ice (also called dry ice) and a machine that simulates the Martian atmosphere. When the cold ice made contact with a much-warmer bed of Mars-like sediment, part of the ice instantly transformed from a solid to a gas (a process called sublimation), forming spidery cracks where the escaping gas pushed through the ice.
Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant, also known as the Cygnus Loop, has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon. The featured picture is a Hubble Space Telescope mosaic of six images together covering a span of only about two light years, a small part of the expansive supernova remnant. In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.
Four moons are visible on the featured image – can you find them all? First – and farthest in the background – is Titan, the largest moon of Saturn and one of the larger moons in the Solar System. The dark feature across the top of this perpetually cloudy world is the north polar hood. The next most obvious moon is bright Dione, visible in the foreground, complete with craters and long ice cliffs. Jutting in from the left are several of Saturn’s expansive rings, including Saturn’s A ring featuring the dark Encke Gap. On the far right, just outside the rings, is Pandora, a moon only 80-kilometers across that helps shepherd Saturn’s F ring. The fourth moon? If you look closely inside Saturn’s rings, in the Encke Gap, you will find a speck that is actually Pan. Although one of Saturn’s smallest moons at 35-kilometers across, Pan is massive enough to help keep the Encke gap relatively free of ring particles. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 and was directed to enter Saturn’s atmosphere, where it surely melted.
The Mars Ingenuity Helicopter, all four landing legs down, was captured here on sol 39 (March 30) slung beneath the belly of the Perseverance rover. The near ground level view is a mosaic of images from the WATSON camera on the rover’s SHERLOC robotic arm. Near the center of the frame the experimental helicopter is suspended just a few centimeters above the martian surface. Tracks from Perseverance extend beyond the rover’s wheels with the rim of Jezero crater visible about 2 kilometers in the distance. Ingenuity has a weight of 1.8 kilograms or 4 pounds on Earth. That corresponds to a weight of 0.68 kilograms or 1.5 pounds on Mars. With rotor blades spanning 1.2 meters it will attempt to make the first powered flight of an aircraft on another planet in the thin martian atmosphere, 1 percent as dense as Earth’s, no earlier than April 11.
NASA’s Mars rover Curiosity recently posed for a selfie in front of a beautiful Martian rock outcrop called “Mont Mercou,” after probing the area for clues about the Red Planet’s past.
Curiosity landed inside Mars’ 96-mile-wide (154 kilometers) Gale Crater in August 2012 with a primary goal to find out if the planet is, or was, suitable for life. Earlier in March, the rover arrived at a scenic rock formation as it traversed the slopes of Mount Sharp — a 3-mile-tall (5 km) mountain located at the center of Gale Crater, which Curiosity has been climbing since September 2014.
This new rock formation — nicknamed Mont Mercou after a mountain in France — stands about 20 feet (6 meters) tall and can be seen to the left of the rover in the new selfie, which NASA released Tuesday (March 30).
The very first exoplanets were finally discovered in the early 1990s, and since then over 4,000 have been caught floating about in the inky pool of deep space. It’s clear that the cosmos is swimming with alien worlds, and some are pretty damn peculiar.
In recent years, astronomers have confirmed the existence of so-called “cotton candy” planets: portly, Jupiter-size worlds that are remarkably lightweight. These oddities have densities comparable to cotton candy, hence the moniker. Saturn is famous in our own solar system for being of such low density that it could float in a big enough bathtub, and these exoplanets make our stellar neighborhood’s gas giant look like a lead weight in comparison.
Astronomers have detected X-rays from Uranus for the first time, using NASA’s Chandra X-ray Observatory. This result may help scientists learn more about this enigmatic ice giant planet in our solar system.
Uranus is the seventh planet from the Sun and has two sets of rings around its equator. The planet, which has four times the diameter of Earth, rotates on its side, making it different from all other planets in the solar system. Since Voyager 2 was the only spacecraft to ever fly by Uranus, astronomers currently rely on telescopes much closer to Earth, like Chandra and the Hubble Space Telescope, to learn about this distant and cold planet that is made up almost entirely of hydrogen and helium.
As the team led by Prof. Tajmar reported last weekend at the “Space Propulsion Conference 2020 + 1” (which was postponed due to the Corona pandemic) and published in three accompanying papers in the “Proceedings of Space Propulsion Conference 2020 + 1” (Paper 1, Paper 2, Paper 3), they had to confirm the previously discussed interim results, according to which the EmDrive does not develop the thrust previously observed by other teams (such as NASA’s Eagleworks and others). The team also confirmed that the already measured thrust forces can be explained by external effects, as they have now been proven by Tajmar and colleagues using a highly sensitive experimental and measurement setup.