الجمعة، 27 يناير 2023

This Week in Space: a Comet, a Cosmological Wall, and a Very Cold Chamaeleon

This image by NASA’s James Webb Space Telescope’s Near-Infrared Camera (NIRCam) features the central region of the Chamaeleon I dark molecular cloud, which resides 630 light years away. The cold, wispy cloud material (blue, center) is illuminated in the infrared by the glow of the young, outflowing protostar Ced 110 IRS 4 (orange, upper left). The light from numerous background stars, seen as orange dots behind the cloud, can be used to detect ices in the cloud, which absorb the starlight passing through them. An international team of astronomers has reported the discovery of diverse ices in the darkest regions of a cold molecular cloud measured to date by studying this region. This result allows astronomers to examine the simple icy molecules that will be incorporated into future exoplanets, while opening a new window on the origin of more complex molecules that are the first step in the creation of the building blocks of life.

Hello, folks, and welcome back to your favorite Friday roundup of all the space news fit to print. This week we’ve got experimental rocket engines, a gigantic map, and galaxies galore. The James Webb Space Telescope found hydrogen in a galaxy more than eight billion light years away, and the coldest ice ever, but it’s currently down due to a software glitch.

Closer to home, Rocket Lab launched their Electron rocket from US soil for the first time. NASA came together for a day of remembrance that somehow managed to be both somber and ineffably sweet.

JWST Spots the Coldest Chamaeleon

If you wish to make an apple pie from scratch, you must first invent the universe. And somewhere along the way, you’ll need one of the ancient molecular clouds of dust and ice from which stars and habitable planets like Earth are born. This week, Webb scientists announced that the telescope has spotted just such a place. It’s a stellar nursery called the Chamaeleon I cloud, loaded with these primordial crystals. That’s the tableau you’re seeing in the image above — you can tell it’s from Webb by those iconic six-pointed stars. The ice contains traces of sulfur and ammonia, along with simple organic molecules like methanol. And at just ten degrees above absolute zero, it’s the coldest ice ever found.

“We simply couldn’t have observed these ices without Webb,” said Klaus Pontoppidan, a Webb project scientist involved in the research. “The ices show up as dips against a continuum of background starlight. In regions that are this cold and dense, much of the light from the background star is blocked, and Webb’s exquisite sensitivity was necessary to detect the starlight and therefore identify the ices in the molecular cloud.”

‘Virginia Is for Launch Lovers’: Rocket Lab Launches Electron Rocket From US Soil

Late Wednesday evening, aerospace startup Rocket Lab successfully launched its Electron rocket from NASA’s Wallops Flight Facility in Virginia. This was the 33rd launch of the Electron, but its first launch from American soil.

Electron is a 59-foot, two-stage, light-duty kerosene rocket. It’s powered by nine Rutherford engines, which my colleague Ryan Whitwam notes are semi-famous in aerospace for being largely 3D printed.

The Electron isn’t reusable — but in 2021, Rocket Lab announced the Neutron. Designed for reusability, the Neutron will have about a third of the lift capacity of a Falcon 9.

NASA ‘Rotating Detonation Engine’ Aces Hot Fire Tests

Speaking of 3D-printed rocket engines: NASA announced this week that it has successfully validated a next-gen rocket engine it hopes will revolutionize rocket design. The new engine generates thrust “using a supersonic combustion phenomenon known as a detonation.” And this is no experimental error — their full-scale alpha build produced more than 4,000 pounds of thrust at full throttle.

These engines get their name (rotating detonation rocket engine, or RDRE) from the unique way they produce thrust. Detonation waves echo around a circular chamber, wringing out every bit of energy from the rocket fuel. It’s great for efficiency, but it puts the whole system under extreme pressure. Undaunted, NASA turned to an advanced additive manufacturing process, even developing its own bespoke metal alloy for the task.

According to the agency, the RDRE incorporates the agency’s GRCop-42 copper alloy into a powder bed fusion (PBF) additive manufacturing process. PBF uses a laser or particle beam to seamlessly fuse ultra-fine particles. It’s a lot like the sintering process used to make the space shuttle rocket engines — and even they had to be actively cooled by the rockets’ own cryofuel, in order to withstand the unearthly temperatures and pressures of takeoff. If the design holds up, NASA intends to use RDRE in its efforts to establish a long-term presence off-planet.

Dark Energy Detector Plots Largest-Ever Map of Galaxy

Astronomers have created a gargantuan map of the Milky Way, using a telescope built to detect dark energy. Featuring more than three billion stars, it focuses on the galaxy’s orbital plane — a region notoriously difficult to study.

Earth’s atmosphere scatters starlight so that points of light turn into point clouds. So, the astronomers just dove right in. To isolate different stars and celestial objects, the group used some extra-snazzy math to get rid of noise. This allowed them to “paint in” the proper background, letting them tell one star from another.

Astronomers have released a gargantuan survey of the galactic plane of the Milky Way. The new dataset contains a staggering 3.32 billion celestial objects — arguably the largest such catalog so far. The data for this unprecedented survey were taken with the US Department of Energy-fabricated Dark Energy Camera at the NSF’s Cerro Tololo Inter-American Observatory in Chile, a Program of NOIRLab. Credit: Saydjari et al., via NoirLab

“One of the main reasons for the success of DECaPS2 is that we simply pointed at a region with an extraordinarily high density of stars and were careful about identifying sources that appear nearly on top of each other,” said Andrew Saydjari, lead author on the (open-access!) paper accompanying the gigantic map. “Doing so allowed us to produce the largest such catalog ever from a single camera, in terms of the number of objects observed.”

Experts: Milky Way Too Large for Its “Cosmological Wall”

The history of astronomy has been all about recognizing that our place in the universe isn’t all that special. We’ve gone from the center of all existence to just another planet orbiting an average star in one of billions and billions of galaxies. However, a new simulation hints that there might be something special about the Milky Way after all.

Yepun, one of the four Unit Telescopes of the Very Large Telescope (VLT) at the European Southern Observatory, studies the center of the Milky Way. Yepun’s laser beam creates an artificial “guide star” to calibrate the telescope’s adaptive optics. Image: ESO/Yuri Beletsky

The model suggests that the Milky Way is far larger than it should be, based on the scale of the “cosmological wall”: an incomprehensibly huge semi-planar structure occupied by the Milky Way and other galaxies in the Local Group.

Scientists Detect Atomic Hydrogen in Most Distant Galaxy Ever

An international team of astronomers announces the discovery of cold atomic hydrogen, more than eight billion light-years from Earth. Cooler than ionized plasma but warmer than molecular hydrogen gas, atomic hydrogen is the raw fuel of coalescing stars. The researchers used gravitational lensing to spot the telltale — but deeply redshifted — 21cm line.

Webb Spies Centaur Chariklo’s Delicate Rings

Named for the daughter of Apollo, Chariklo is a centaur: a Kuiper belt object that orbits out past Saturn. It’s the first of its kind ever found with a confirmed ring system. The thing really is tiny; it’s about 160 miles in diameter and has less than two percent the mass of Earth. But a new report from Webb shows even that much mass is enough to sustain two slender rings, for a time.

In a remarkable stroke of scientific luck, the telescope was pointed just right to catch Chariklo as it passed in front of a star. When it did, the star’s light fluttered in a way that betrayed the presence of the rings.

Nothing less than delighted, the astronomers report that Chariklo’s rings are two and four miles wide, respectively. But the asteroid actually has something in common with the Chamaeleon I cloud. Chariklo’s surface is covered in exotic phases of water ice that only Webb can see.

Principal investigator Dean Hines added, “Because high-energy particles transform ice from crystalline into amorphous states, detection of crystalline ice indicates that the Chariklo system experiences continuous micro-collisions that either expose pristine material or trigger crystallization processes.” It’ll be up to the JWST to find out more.

Software Glitch Brings JWST Down for Maintenance

Unfortunately, observations of Chariklo and other celestial bodies will have to wait a while. The JWST had a software glitch this week. Per NASA, the telescope’s Near Infrared Imager and Slitless Spectrograph (NIRISS) “experienced a communications delay within the instrument, causing its flight software to time out.” Unfortunately, this led to a software gridlock.

The telescope is unavailable for science observations because NASA and the Canadian Space Agency are doing root-cause analysis to figure out and fix the problem. But NASA emphasizes that the telescope is fine. There’s no damage and no indication of any danger. If it’s a software problem, it may well be a software fix.

Perseverance Files First Weather Report

Now that it’s been on Mars for a while, the Perseverance rover has filed an authoritative report on Martian weather. The number one takeaway: It’s cold on the Red Planet! The average surface temperature is -67C.

It’s also windy on Mars. Since Mars has an atmosphere, it has surface weather. It also has an axial tilt, so it has seasons, just like Earth. Dust storms can envelop Mars’ entire northern hemisphere.

Plumes of darker, subsurface dust waft to the surface when the sun warms Martian sands beneath transparent sheets of ice. Mars’ shifting winds then blow these plumes of dust into V-shaped patterns. Astronomers are using the plumes to learn more about Mars’ weather and surface climate. Image: NASA

Perseverance is covered in a suite of sensors that constantly monitor wind speed and direction, atmospheric pressure, temperature, humidity, and dust. Together, they make the rover’s Mars Environmental Dynamics Analyzer (MEDA).

Here, you can see the MEDA sensors extending from the rover’s mast below the iconic ChemCam.

“The dust devils are more abundant at Jezero than elsewhere on Mars and can be very large, forming whirlwinds more than 100 meters in diameter. With MEDA we have been able to characterize not only their general aspects (size and abundance) but also to unravel how these whirlwinds function,” says Ricardo Hueso, of the MEDA team.

Perseverance has captured numerous dust devils as they sweep through Jezero Crater. However, to get that data, MEDA’s exposed sensors also face damage from the harsh radiation environment, extreme temperature swings, and the ever-present Martian dust. A dust devil in January of last year kicked up enough debris that it damaged one of MEDA’s wind instruments. Still, the rover perseveres.

NASA’s Bittersweet 2023 Day of Remembrance

Every year, NASA holds a memorial for staff, astronauts, and alumni who have died. 2023’s Day of Remembrance holds a somber significance, as Feb. 1 is the 20th anniversary of the Columbia disaster. Unfortunately, this year’s fallen also included Apollo 7 pilot Walt Cunningham, who passed earlier this month. Cunningham was the last surviving member of the Apollo 7 crew.

Photo Credit: NASA/Aubrey Gemignani via NASA HQ Flickr

As in years past, NASA staff gathered this week at space centers and labs around the country, to honor the sacrifices of those who have given their lives in pursuit of exploration and discovery. But they did it in a way only NASA could do. They held nationwide town-hall safety meetings, to reflect on and improve NASA’s aerospace safety culture.

Ask not for whom the safety alarm tolls; it tolls for thee. NASA safety-culture town hall meeting at its Washington headquarters after the Arlington memorial service. Image: NASA/Keegan Barber via NASA HQ Flickr

What a fitting way to honor lives lost, while still reaching for the stars. Town-hall safety culture meetings. We love you guys. Never change.

Psyche Mission Now Targeting October 2023 Launch

Steady as she goes: After a year’s delay and a missed launch window, NASA’s Psyche mission team is getting the spacecraft in shape to launch this year. In a blog post, the agency said, “After a one-year delay to complete critical testing, the Psyche project is targeting an October 2023 launch on a SpaceX Falcon Heavy rocket.”

When it launches, Psyche will carry a technology demo for NASA’s shiny new Deep Space Optical Communications (DSOC) network. DSOC systems will use lasers for high-bandwidth communications between Earth and the Moon, Mars, and beyond. Beyond a deluge of scientific data, NASA expects that the network will be able to handle high-def images and video.

Skywatchers Corner

Comet C/2022 E3 (ZTF) is a long-period comet that last visited Earth in the time of the Neanderthals. Now it’s back for another close approach. And although we didn’t know this when we found it last year, it turns out the comet’s tail glows pale green, like a luna moth under a streetlight.

The robin’s-egg glow of Comet C/2022 E3 (ZTF)’s tail shines against its twin tails. Image: Dan Bartlett/NASA

At first, astronomers thought it might require binoculars to catch a glimpse of the thing. However, as ExtremeTech’s Adrianna Nine writes, the comet is now visible to the naked eye in places across much of the Northern Hemisphere.

Our verdant visitor will continue its brightening trend while it sails toward Earth. It will make its closest approach to us on February 2: perhaps too soon for a Valentine’s Day spectacular, but right on time for Imbolc, Candlemas, and Groundhog Day.

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