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.
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.
Within a few days, Ingenuity will be on the surface of Mars. Until now it has been connected to the Perseverance rover, which allowed Ingenuity to charge its battery as well as use a thermostat-controlled heater powered by the rover. This heater keeps the interior at about 45 degrees F through the bitter cold of the Martian night, where temperatures can drop to as low as -130F. That comfortably protects key components such as the battery and some of the sensitive electronics from harm at very cold temperatures.
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.
Just a couple of years ago, astronomers and astrophysicists were baffled by the observation of a synchronized behavior in galaxies, which can not be explained by their individual gravitational fields. Such was the case of a study lead by Joon Hyeop Lee, an astronomer at the Korea Astronomy and Space Science Institute, and published in The Astrophysical Journal in October 2018, reporting hundreds of galaxies rotating in sync with the motions of galaxies that were tens of millions of light years away.
Given the fact that from our known theories, in principle it would be impossible that galaxies separated by megaparsecs (millions of light years) could directly interact with each other, their interaction happens across distances that are too large to be explained by their gravitational force. It is then speculated that some unacknowledged force must be acting.
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.
Have you ever seen a rocket launch – from space? A close inspection of the featured time-lapse video will reveal a rocket rising to Earth orbit as seen from the International Space Station (ISS). The Russian Soyuz-FG rocket was launched in November 2018 from the Baikonur Cosmodrome in Kazakhstan, carrying a Progress MS-10 (also 71P) module to bring needed supplies to the ISS. Highlights in the 90-second video (condensing about 15-minutes) include city lights and clouds visible on the Earth on the lower left, blue and gold bands of atmospheric airglow running diagonally across the center, and distant stars on the upper right that set behind the Earth. A lower stage can be seen falling back to Earth as the robotic supply ship fires its thrusters and begins to close on the ISS, a space laboratory that celebrated its 20th anniversary in 2018. Astronauts who live aboard the Earth-orbiting ISS conduct, among more practical duties, numerous science experiments that expand human knowledge and enable future commercial industry in low Earth orbit.
Scientists have reported the discovery of a rare, medium-sized black hole that may help answer one of the more tantalizing questions in astronomy: how do their supermassive counterparts come into being?
To play on Carl Sagan’s famous words “If you wish to make black hole jets, you must first create magnetic fields.” The featured image represents the detected intrinsic spin direction (polarization) of radio waves. The polarizationi is produced by the powerful magnetic field surrounding the supermassive black hole at the center of elliptical galaxy M87. The radio waves were detected by the Event Horizon Telescope (EHT), which combines data from radio telescopes distributed worldwide. The polarization structure, mapped using computer generated flow lines, is overlaid on EHT’s famous black hole image, first published in 2019. The full 3-D magnetic field is complex. Preliminary analyses indicate that parts of the field circle around the black hole along with the accreting matter, as expected. However, another component seemingly veers vertically away from the black hole. This component could explain how matter resists falling in and is instead launched into M87’s jet.
What are those red filaments in the sky? They are a rarely seen form of lightning confirmed only about 30 years ago: red sprites. Recent research has shown that following a powerful positive cloud-to-ground lightning strike, red sprites may start as 100-meter balls of ionized air that shoot down from about 80-km high at 10 percent the speed of light. They are quickly followed by a group of upward streaking ionized balls. The featured image was taken earlier this year from Las Campanas observatory in Chile over the Andes Mountains in Argentina. Red sprites take only a fraction of a second to occur and are best seen when powerful thunderstorms are visible from the side.
A little more than a month ago, NASA’s Perseverance rover made a daring landing on the Martian surface that’s now been watched (and rewatched) by millions. But now, the real work begins. Tucked deep inside Percy is an instrument designed to inhale Mars’ carbon dioxide-rich atmosphere and exhale oxygen. Essentially, it’s a mechanical tree—one that could reshape humanity’s future on the Red Planet.
Mars’ atmosphere is roughly 1 percent the density of Earth’s. If we have any dreams of living and working on the Red Planet, we’ll need to generate and store oxygen.
“What breathes the most on a mission to Mars? Not the people,” Michael Hecht, the Associate Director for Research Management at MIT’s Haystack Observatory and the principle investigator of NASA’s MOXIE project, tells Popular Mechanics. “It’s the rocket that is going to take you home from Mars, that is going to get you off the planet.”
According to NASA’s estimates, a four-person crew will need a lot of propellant—approximately 15,000 pounds of fuel and roughly 55,000 pounds of oxygen—to generate the thrust needed to leave the Martian surface and return home. Lugging all of that oxygen from Earth is a hassle.
That’s where the Mars Oxygen In-Situ Resource Utilization Experiment, or MOXIE, comes in.
Who knows what evil lurks in the eyes of galaxies? The Hubble knows – or in the case of spiral galaxy M64 – is helping to find out. Messier 64, also known as the Evil Eye or Sleeping Beauty Galaxy, may seem to have evil in its eye because all of its stars rotate in the same direction as the interstellar gas in the galaxy’s central region, but in the opposite direction in the outer regions. Captured here in great detail by the Earth-orbiting Hubble Space Telescope, enormous dust clouds obscure the near-side of M64’s central region, which are laced with the telltale reddish glow of hydrogen associated with star formation. M64 lies about 17 million light years away, meaning that the light we see from it today left when the last common ancestor between humans and chimpanzees roamed the Earth. The dusty eye and bizarre rotation are likely the result of a billion-year-old merger of two different galaxies.