Okay, so we all know that the Sun is heading into solar maximum. That means it’s quite a bit more active, with sunspots, coronal mass ejections, and flares aplenty. But, luckily for us, the Sun isn’t as active as the members of the binary star system V1355 Orionis. One of its stars periodically releases superflares. These are ten times more extensive than the largest solar flare ever recorded on the Sun.
On Earth, flares from the Sun often kick up geomagnetic storms (often referred to as “space weather”). In the worst cases, those storms can interfere with our technology. They can disrupt communications, shut down power grids, and damage satellites. Really powerful flares, like the ones at V1355 Orionis, could have even worse effects. That includes affecting the evolution of any nearby planets and their atmospheres. Certainly, if they’re strong enough, such flares could wipe out any life on those worlds. So, understanding flares on stars, and why they occur, is important.
A team of astronomers led by Shun Inoue at Kyoto University in Japan monitored this binary system using the 3.8-meter Seimei Telescope and the Transiting Exoplanet Survey Satellite (TESS). They managed to catch a superflare that began with a massive, high-velocity prominence. It was one of the most powerful ejections from a star. The velocity of the eruption was at least 990 kilometers per second—which is well over the star’s 347 km/sec escape velocity. It developed into a coronal mass ejection that carried trillions of tons of material away into space.
Understanding Flares from V1355 Orionis
The measurements made by the team are aimed at helping astronomers understand how superflares and eruptions begin. The V1355 Orionis system is classified as an RS CVn-type star. The classification comes from the RS Canum Venaticorum system, which is a variable containing close binary stars. These stars are typically magnetically active, with large superflares bursting out from their surfaces. They also often have large starspots. There are various subgroups of these systems, including flare stars like V1355 Orionis. Some are quite bright in X-rays and radio frequencies.
V1355 Orionis has both a K- and G-type star. The K star is a subgiant and the source of the superflare. The results of these observations show the need for more modeling and simulation of prominences on this type of star, particularly in a binary system. Among other things, it’s important to get a better idea of how much mass the star loses through its prominences and associated coronal mass ejections.
The superflare V13555 Orionis is useful to understand not just how they happen there, but the mechanism that causes prominences and flares on our Sun. Further observations should help nail down just what’s going on at the surface and with the magnetic fields on both types of stars.
In our solar system, the planetary orbits all have a similar orientation. Their orbital planes vary by a few degrees, but roughly the planets all orbit in the same direction. This invariable plane as it’s known also has an orientation within a few degrees of the Sun’s rotational plane. Most planetary systems have a similar arrangement, where planetary orbits and stellar rotation are roughly aligned, but a few exoplanets defy this trend, and we aren’t entirely sure why.
Common orientation within a planetary system makes sense given how planetary systems form. The protostellar cloud out of which a star and its planets form usually has some inherent rotational momentum. As a star begins to coalesce, a protoplanetary disk forms around the star. Since the planets form within this disk, they all end up with similar orbits. Things can be more complicated with binary or multiple-star systems, but you’d expect single-star planetary systems to have an invariable plane similar to ours. However, this isn’t true for a planetary system known as WASP-131, as a recent study shows.
WASP-131 is known to have at least one planet, 131b. It’s a hot gas planet with a mass a bit less than Saturn that orbits 131 every five days. Earlier studies of 131b found the planet unusual because of how thick its atmosphere is. Although its mass is only a quarter that of Jupiter, its diameter is 20% larger than Jupiter’s. 131b has such a low density for a gas planet that it’s known as a super-puff planet.
The planet was discovered via the transit method, which means it passes in front of its star from our point of view. It’s an effective way to find exoplanets, but it can also be used to verify the rotational motion of the star. Because of stellar rotation, light coming from the region of the star rotating toward us is slightly blueshifted, and light from the region rotating away from us is slightly redshifted. This means that spectral lines from the star are blurred a bit. The effect is known as Doppler broadening. As the planet passes in front of the star, it blocks a part of the blueshifted and redshifted regions in turn. This causes the spectral lines of the star to shift a bit. This Rossiter–McLaughlin effect as it’s known allows astronomers to measure the orientation of stellar rotation.
An illustration of the Rossiter–McLaughlin effect. Credit: Wikipedia user Autiwa
When the team analyzed the rotation of WASP-131, they found it wasn’t similar to that of its planet. The orbit of 131b is tilted about 160 degrees from the rotational plane of the star, meaning that it is in a high, almost polar retrograde orbit. Of course, this raises the question of just how the planet could have gotten such an odd orbit.
One idea is a process known as the Kozai effect. Dynamical interactions between the planet, its star, and other planets in the system can cause the orbit to shift away from the invariant planet. We see this in our own solar system with Pluto and Neptune, which has tilted Pluto’s orbit over time. The Kozai effect is more pronounced with smaller planets, however, and interaction between planet and star alone isn’t enough to explain such an inclined orbit. Another possibility is a magnetic interaction between the planet and the protoplanetary disk early in its formation period.
Although the mechanism behind the odd orbit isn’t clear, it does follow a pattern seen with many hot gas exoplanets. About a quarter of them have significantly tilted orbits. It seems that these planets sometimes get way out of line.
We all know that black holes are destructive monsters. Their tremendous gravitational pull sucks in anything that gets in the way. This is particularly true for supermassive black holes in the hearts of galaxies. They can tear apart stars. And, every so often—like once every, 10,000 years, that happens. The star passes too close and the black hole’s gravity shreds it.
When a star experiences a “tidal disruption event” (TDE), it lights up the core of the galaxy. Astronomers know of about 100 of these TDEs in distant galaxies. Most of the light they detect from that catastrophic event arrives in the form of X-rays and optical light. But, it turns out they can tune into infrared signals from a TDE, and MIT scientists recently captured one occurring in the galaxy NGC 7392. The galaxy lies about 137 million light-years from Earth, and the discovery at its heart is one of the first times astronomers have seen an infrared view of star-shredding by a black hole.
They named the event “WTP14adbjsh.” Because dust clouds hid the view, there were no X-ray or ultraviolet views. However, the dust absorbed a great deal of radiation from the event, and that caused the clouds to emit infrared light.
Capturing a View of a Black Hole Shredding a Star
The discovery came about almost by accident as MIT postdoc Christos Panagiotou and his colleagues were combing through data from the NEOWISE mission. It has been making scans of the sky in infrared wavelengths since 2010. The team discovered a bright flash that appeared in the data. Panagiotou wasn’t looking for tidal disruption events, actually. The team was searching for transients—sources of light that appear and then disappear. Then, they discovered this flash. “We could see there was nothing at first,” Panagiotou recalled. “Then suddenly, in late 2014, the source got brighter and by 2015 reached a high luminosity, then started going back to its previous quiescence.”
Infrared signs of the closest tidal disruption event (TDE) to date. In this event, a star wandered too close to a central supermassive black hole. A bright flare was detected from the galaxy NGC 7392 in 2015 (top left panel). Observations of the same galaxy were taken in 2010-2011 (top right), prior to the TDE. The bottom left shows the difference between the first two images, representing the actual, detected TDE. For comparison, the bottom right panel shows the same galaxy in the optical waveband. Courtesy of the researchers
They eventually traced the flash to NGC 7392 and began asking what kind of astrophysical process could create it. “For instance, supernovae are sources that explode and brighten suddenly, then come back down, on similar timescales to tidal disruption events,” Panagiotou said. “But supernovae are not as luminous and energetic as what we observed.”
Eventually, the team figured out that the flash was due to a TDE—that is, a star being ripped apart by a supermassive black hole. It fit the data and, if it panned out, was the closest one astronomers have ever observed.
Proving a TDE
It’s one thing to claim that the transient flash of light was a star getting shredded by a black hole, but how to prove it? First, the team had to understand the black hole and its environment. So, they studied the galaxy. Data from a variety of sources showed the galaxy had a supermassive black hole about 30 million times as massive as the Sun. That’s actually pretty massive. “This is almost 10 times larger than the black hole we have at our galactic center, so it’s quite massive, though black holes can get up to 10 billion solar masses,” Panagiotou said.
For a star to get close enough to encounter the black hole means the galaxy has a population of stars and could be creating some in the vicinity of the black hole. The observations at different wavelengths showed that NGC 7392 is busily creating new stars. However, it’s not as active as some galaxies and is busier than others. It’s considered a “green” star-forming galaxy. That’s because it produces a few stars, enough to provide something for the black hole to eat. It turns out that most TDEs happened in the rare type of “green” galaxy.
However, there’s one other factor to consider. Star-forming galaxies produce a lot of dust, particularly at the core. Infrared light can get through most of the dust, whereas X-ray, optical, or ultraviolet light gets blocked. So, this may be a factor in why astronomers haven’t detected more TDEs in star-forming galaxies when they look using conventional optical telescopes.
The Future of Observing TDEs is Infrared
This discovery points to a need for more infrared observations of galaxies to search out TDEs. “The fact that optical and X-ray surveys missed this luminous TDE in our own backyard is very illuminating and demonstrates that these surveys are only giving us a partial census of the total population of TDEs,” said Suvi Gezari, associate astronomer and chair of the science staff at the Space Telescope Science Institute in Maryland, who was not involved in the study. “Using infrared surveys to catch the dust echo of obscured TDEs … has already shown us that there is a population of TDEs in dusty, star-forming galaxies that we have been missing.”
Interestingly, the TESS satellite (best known for its exoplanet searches) also caught a TDE in 2019. A ground-based survey called the All-Sky Automated Survey for Supernovae (ASAS-SN) alerted astronomers. They were able to get other observations, including from TESS to follow the progress of the event.
As global warming heats up our atmosphere a degree at a time, the world’s glaciers are paying the price. In ten years, they’ve shrunk by a total of 2 percent. To look at it another way, collectively the glaciers have lost 2,720 gigatons of ice thanks to warming air.
How do we know this? The European Space Agency’s CryoSat mission provided data about the 2010-2020 loss of glacier ice. At least 89 percent of it is due to warming temps. In addition, ice being lost from glaciers is contributing more to sea-level rise than the ice being lost from either of the giant ice sheets on Greenland and Antarctica.
Processing Data to Look at Glaciers
Dr. Livia Jakob of Earthwave and Noel Gourmelen of the University of Edinburgh in the UK just published a data processing technique that revolutionized the use of CryoSat data. It uncovered a lot of new data about icy terrains and glaciers that led to the discovery of ice loss.
“We’ve been able to use this technique to study glaciers all over the world,” explained Jakob. “We can report that, in total, mountain glaciers lost 2% of their volume between 2010 and 2020.
The new analysis of CryoSat data revealed the 2720-gigaton loss, she said. “This can be imagined as a giant ice cube, bigger than Europe’s highest mountain, which is quite shocking,” she said. “Importantly, we also found that air temperature, which causes the ice surface to melt, accounts for 89% of this ice loss.”
Warmer air temperatures are responsible for this decreasing “surface mass balance”. However, the research team also found that something called ‘ice discharge’ was responsible for the other 11% of ice lost. That’s a factor associated with glaciers that border a coast. There, warmer ocean waters help thin the “front” of the ice flow.
“I’m sure most people have seen photographs taken at different times that show how a glacier terminus has retreated over time,: Gourmelen said. ” And we can see this from satellite images too. But we need to measure how a glacier’s volume is changing to really make sense of what is happening.”
Refining our Understanding of Glacier Ice Loss
Gormelen explained how the CryoSat data analysis is helping scientists compare ice loss around the world. “The relative contribution of decreasing surface mass balance and increasing ice discharge to sea-level change is well known for the Greenland and Antarctic ice sheets,” he said. “Now we know more about how the atmosphere and ocean are teaming up to melt glaciers. There is still plenty of work to do to refine these numbers, and to incorporate this knowledge into our glacier projections.”
This analysis used data from the satellite when it was in swath altimetry mode. Essentially, the satellite took data over wide swaths of terrain and measured the height of glaciers, water, and land. Such satellite radar altimeters have long monitored changes in the height of the sea surface. They also monitor changes in the height of the huge ice sheets that cover such places as Antarctica and Greenland. The instrument measures the time it takes for a radar pulse to reflect from Earth back to the satellite. Couple that with the exact position of the satellite in space and you get the height of the surface below.
Swath processing allows scientists to study wide areas of ice sheets and glaciers to determine amounts of ice loss. Courtesy ESA.
CryoSat Data: The Canary in the Coal Mine?
Mountain glaciers have long been key indicators of climate change, but estimates of global glacier mass loss have remained limited to a few scientific studies. This is because there are big challenges in mapping and monitoring glaciers. This is largely because they exist in complex rugged terrain. Also, there is no specific satellite mission dedicated to mapping glaciers. This is why the CryoSat data are so valuable.
“I’m sure most people have seen photographs taken at different times that show how a glacier terminus has retreated over time. And we can see this from satellite images too,” said Gourmelen. “But we need to measure how a glacier’s volume is changing to really make sense of what is happening.”
CryoSat’s altimeter isn’t specifically designed to measure changes in mountain glaciers. But, using the satellite’s swath mapping technique for icy terrains is invaluable. It has enabled scientists to fine-tune their estimates of ice loss in glaciers and make predictions of resulting sea level rise.
CryoSat has been busy measuring ice loss around the world since its launch. In 2021, its data revealed that between 2010 and 2019, the Gulf of Alaska lost 76 gigatons of ice per year. Asian glaciers lost about 28 gigatons per year. That’s about the equivalent of adding 0.21 and 0.05 mm to sea level rise each year. In 2021, scientists reported that between 1992 and 2020, the polar ice sheets lost 7,560 billion tons of ice. In 2019 Greenland and Antarctica lost 444 billion tons and 168 billion tons of ice respectively.
That same year, scientists reported that the total loss from all the world’s glaciers topped 9 trillion tons of ice. These losses are directly attributable to warming atmospheric temperatures around the world. If the ice sheets continue to lose mass at this pace, the Intergovernmental Panel on Climate Change predicts that they will contribute between 148 and 272 mm to the global mean sea level by the end of the 21st century.
It was an exciting time when, two weeks ago, SpaceX got the clearance it needed to conduct its first orbital flight test with the Starship and Super Heavy launch system. After years of waiting, SN flight tests, static fire tests, and stacking and unstacking, the long-awaited test of the SN24 Starship and BN7 Booster prototype was on! For this flight, SpaceX hoped to achieve an altitude of at least 150 km (90 mi) above sea level, crossing the 100 km (62 mi) threshold that officially marks the boundary of “space” (aka. the Karman Line) and making a partial transit around the world before splashing down off the coast of Hawaii.
Unfortunately, things began to go awry a few minutes into the flight as the Starship prototype failed to separate from the booster, sending the rocket into a spin that ended in an explosion. While Musk and SpaceX issued statements that the test was largely successful and lots of valuable data was obtained, residents and environmental researchers claim the explosion caused damage to houses in the area and the local environment. In response, the FAA has launched a “mishap investigation,” temporarily grounding the Starship until the explosion’s impact can be assessed.
The timing of the flight test was certainly fortuitous, falling on April 20th (4/20) exactly as Musk had previously predicted. Everything appeared to be in the green as all 33 engines of the BN7 booster fired, and the fully-stacked and fueled prototype lifted off without incident. About three and a half minutes into the flight, when stage separation was supposed to occur, the Starship began an uncontrolled tumble and was destroyed by onboard charges. The SN24 and BN7 managed to reach an altitude of 40 km (25 miles) before the anomaly occurred.
Musk commended the ground teams, tweeting, “Congrats @SpaceX team on an exciting test launch of Starship! Learned a lot for next test launch in a few months.” At the same time, it was clear that some sizeable changes needed to be made. In addition to the mid-air explosion, the launch also destroyed the launchpad, which sent debris flying in all directions. This raised the issue of a deluge system that the Boca Chica launch site does not have (unlike other launch facilities). These systems rely on a “flame trench” to channel rocket exhaust and water or foam to suppress shockwaves and flames.
Musk was sure to temper expectations before the flight, saying in a Twitter discussion on April 16th that when you have a spacecraft that’s got “33 engines on the booster, got six engines on the upper stage of the ship. It’s a lot of engines! It’s like having a box of grenades, really big grenades.” He was also sure to cite SpaceX’s track record with rapid prototyping, which has always involved “testing to failure” and a lot of trial and error:
“This is really kind of the sort of first step in a very long journey that will require many, many flights. For those that have followed the history of Falcon 9, and Falcon 1 actually, and our attempts at reusability, I think it might have been close to 20 attempts before we actually recovered a stage. And then it took many more flights before we had reusability that was meaningful, where we didn’t have to rebuild the whole rocket.”
To residents and environmentalists, the test was not an occasion for celebration. Ever since SpaceX broke ground in Boca Chica and began testing, Musk has had a strained relationship with the locals, who have frequently complained about noise and the impact these tests have on their communities and the natural environment. According to Pablo De La Rosa, a reporter with Texas Public Radio (TPR) and NPR, there were multiple reports of “particulates” raining down on South Padre Island up the coast and on the nearby town of Port Isabel.
The IOP/SS system deploys almost a half-million gallons of water in one minute to protect the SLS during launch. Credit: NASA
Residents in the town also reported broken windows “and ash-like particles covering their homes and schools.” The Sierra Club cited similar reports, with Dan Cortez (Lone Star chapter director) stating in an interview with CNBC that the destruction of the launchpad caused collateral damage that could have been much worse. “Concrete shot out into the ocean, and risked hitting the fuel storage tanks which are these silos adjacent to the launch pad,” he said. With mid-air explosions, there are also concerns that residual propellant (which are often toxic) could rain down on the surface, causing environmental damage.
A post-launch assessment by the Federal Aviation Administration (FAA) is standard practice in cases like this. As the Administration explained in a statement regarding Recent Aviation Accidents and Incidents (issued on April 20th):
“The FAA will oversee the mishap investigation of the Starship / Super Heavy test mission. A return to flight of the Starship / Super Heavy vehicle is based on the FAA determining that any system, process, or procedure related to the mishap does not affect public safety. This is standard practice for all mishap investigations. The FAA is responsible for protecting the public during commercial space transportation launch and reentry operations.”
In other words, the FAA has effectively grounded SpaceX’s testing efforts at Boca Chica until they can determine if future flight tests will threaten public health, safety, and the local environment. This will likely result in a list of mandatory actions that SpaceX must complete to keep its license and resume testing. At this juncture, Musk is already prepared to address the issue of a deluge system, which he has admitted his crews looked at in the past but decided was unnecessary. Nevertheless, he also hinted before the launch that “melting the launch pad” was a real possibility.
In any case, Musk appeared to be admitting on April 21st that the decision to proceed without first installing a cooling system beneath the launchpad was a mistake, tweeting: “3 months ago, we started building a massive water-cooled, steel plate to go under the launch mount. Wasn’t ready in time & we wrongly thought, based on static fire data, that Fondag would make it through 1 launch. Looks like we can be ready to launch again in 1 to 2 months.”
At this juncture, a month or two seems optimistic, considering that the full impact could take weeks and corrective actions could take much longer to implement. It could turn out that the FAA will demand that a full deluge system is necessary, that additional protections are needed to prevent debris from striking fuel tanks, and that SpaceX install a launch abort system that will force the Starship and Super Heavy to separate in the event of an anomaly. This last item would ensure that at least the booster (the most explosive element) can remove itself and return safely to a landing site.
It’s even also remotely possible the FAA will revoke SpaceX’s license, and Musk will decide to relocate all testing to Cape Canaveral, where SpaceX is still working on a second launch facility. Then again, this may all be resolved shortly, and SpaceX could be testing prototypes again by mid-summer. As the company’s adage famously goes, “Launch. Recover. Repeat.” In this case, “recover” may mean repairing the damage caused by a test gone wrong and ensuring it never happens again. But the next step remains the same – Repeat!
Or, to paraphrase another famous adage, “Explosion will continue until launches improve!”
Close-orbiting binaries are a ticking time bomb. Over time they spiral ever closer to each other until they merge in a cataclysmic explosion such as a supernova. But in the middle of their story, things can get interesting. Some stars collapse into a white dwarf before merging with their partner, others edge so close to each other that their surfaces touch for a time, becoming contact binaries before finally colliding. But one newly discovered binary system will have a wild ride before its final demise.
The system is known as SSN 7, and it is a spectroscopic binary in the Small Magellanic Cloud. Spectroscopic means the two stars are so close to each other and so far away that we can’t resolve them as individual stars. Instead, we know they are binary by observing the redshift and blueshift of their spectral lines. From the spectral line data, astronomers can calculate their mutual orbits, and thus their masses.
The larger star is about 55 solar masses, and the smaller one is about 32 solar masses. Interestingly, the smaller one is the “primary” star, meaning that it’s the brighter of the two. This suggests that the smaller star is already feeding off the larger one in the early stage of merging. They orbit each other every three days, and their gravitational centers are only about 40 solar radii apart. They orbit so closely that they have to be a contact binary.
The mergers of compact objects discovered so far by LIGO and Virgo (in O1, O2 and O3a). The diagram shows black holes (blue), neutron stars (orange) and compact objects of unknown nature (grey), which were detected by their gravitational-wave emission. Each merger of a binary system corresponds to three compact objects shown: the two merging objects and the result of the merger. A selection of black holes (violet) and neutron stars (yellow) discovered by electromagnetic observations is shown for comparison. Image Credit: LIGO Virgo Collaboration / Frank Elavsky, Aaron Geller / Northwestern
Based on their orbits, the two stars will eventually merge in about 18 billion years. But given their masses, these stars won’t live long enough to merge. Stars above about 20 solar masses become supernovae before collapsing to become black holes. The larger one will likely become a black hole in about 700,000 years, and the smaller one about 200,000 years after that. This system will experience two supernovae within the next million years, only to merge as black holes billions of years later.
What makes this system particularly useful to astronomers is that it is squarely in the middle ground of binary systems. Most massive stars are part of close binary systems. We see lots of them as stable binaries not in the process of merging, and we have observed lots of merging stellar-mass black holes through gravitational wave astronomy. Until this system, we haven’t observed a merging binary system that will become a black hole merger. It gives us an excellent view of the elder years of these systems, which will help astronomers better understand their evolution.
Our favorite Martian helicopter did it again. The tiny Ingenuity chopper recently did its 51st flight on Mars. It traveled 188 meters this time (about 617 feet) on April 22, 2023, and reached a maximum altitude of 12 meters (about 39 feet) over the Martian surface. During that time, it snapped another image of its Perseverance mothership, waiting patiently on the horizon.
In NASA’s flight log for Ingenuity, the trip achieved a hop from Airfield Mu to Airfield Nu. In addition to the view of Perseverance, it also captured a quick shot of some debris left over from the entry, descent, and landing sequence in early 2021.
Here’s Ingenuity’s view of some debris left over from the entry, descent, and landing sequence that brought her and Perseverance to Mars. Courtesy NASA/JPL-Caltech
Looking Around at the Rover and Its Locale
Currently, the rover is parked at a rock outcrop nicknamed “Echo Creek.” That’s where the Perseverance team is doing distance measurements. The team is also studying the rocks in this region. Orbital images show them as brighter than surrounding areas. They also seem to be fractured into polygon-shaped patterns. All of these rock studies are part of the team’s study of the upper part of the Fan region in Jezero Crater.
Nearby Echo Creek is a small hill called “Mount Julian”, which the rover will be exploring in the very near future. Both crafts are on the edge of Belva Crater. That’s an interesting surface feature with a depth-to-diameter ratio that makes it shallower than other craters. It looks as if the crater walls were broken down or breached at some point. That raises interesting questions about its ancient past. Was it once filled with water? Are the rims eroded? If so, what happened to break them down?
Perseverance and the Big Picture
The Mars Perseverance rover and its little Ingenuity chopper are exploring Jezero Crater on Mars. This region is pretty intriguing because it looks like water played a huge role in shaping the landforms there. The crater itself formed during an ancient impact event. At least 3.5 billion years ago, river channels brought water into the crater and created a lake inside. That carried clay minerals into the crater lake. The whole sequence of events raises questions about how long the water lasted, and whether it sustained any kind of life (probably microbial).
A view of Jezero Crater from space. Perseverance is currently exploring the delta Fan region in the crater. Courtesy NASA/JPL-Caltech.
The Perseverance rover has the instruments and ability to study Mars’s ancient rocks. In fact, until recently, it carried a “pet rock” along in its wheel, only to lose it after 427 days of roaming around. Perseverance drills into surface rocks and provides information to scientists about their chemical makeup and other characteristics. The Ingenuity chopper started out as a tech demonstration of five flights. With 51 achieved, it just keeps going and going, providing unique looks at the landscape and its mothership.
A screen capture from the Mars 2020 rover page showing the April 28 location of Perseverance and the Ingenuity helicopter.
Imagine you’re a lunar astronaut, putting in a hard day’s work building your lab or excavating moon rocks. You get back into the hab and ask, “What’s for dinner?” The answer could be “We’re starting with a Moon salad” featuring lettuce and other goodies grown on the lunar surface. It’s an idea scientists are researching as part of a project called LunarPlant, an effort to figure out ways to grow healthy veggies on the Moon.
The obvious idea is to use hydroponics methods for lunar farming. However, there’s no good Earth soil for planets to anchor into, so they’ll need something else. Galina Simonsen, a researcher at the independent European agency SINTEF, is exploring different approaches to hydroponics and aquaculture.
Artist’s concept of a future farm on the Moon. Places like this could be where lunar inhabitants get their fresh salads and other veggies. Credit: Solsys Mining.
She points out that using lunar regolith is not a great idea because it’s difficult to use for plant growth. And, the “farm environment” has to be indoors since the lunar surface is alternately baked or frozen.
Hydroponics (sometimes called “aquaculture”) needs lots of water. That’s fairly abundant on the Moon, but someone will have to extract, transport, and melt it down for use. “Radar data indicate that the Moon’s polar regions hold more than 600 billion kilograms of ice”, said Simonsen. “This is enough to fill about 240,000 Olympic-sized swimming pools. It is much less than we have on Earth but will be enough to enable humans to maintain some level of activity.”
Moon Salad Substrates Needed
So, that solves the water problem for hydroponics. Anybody who has grown plants in water here on Earth, however, knows that plant roots need anchors. And, those water gardens need fertilizer. “Soil substitutes” such as rockwool solve the first problem. “We’re trying to find out how we can get the plants to grow without collapsing”, said Simonsen. “This involves identifying a growing medium that enables plants to develop a root system that gives them adequate support”, she says.
Here on Earth, folks who use hydroponics depend on the rockwool substitute for dirt. It’s great on Earth, but not a sustainable substitute for lunar farms. “Sending rockwool to the Moon could cost up to NOK 20 million [more than $18 million USD] per kilo”, explained Simonsen. “For this reason, it is important that we can use a material that is entirely circular. It has to be light and multifunctional.”
In other words, lunar farmers need a material recycled from another use. It turns out that the SINTEF team and a group of researchers in Finland have a great substitute. It’s a cellulose-based alternative that comes from plant waste. It looks like compressed hay or straw. And, it would work great as insulation for transporting equipment to the Moon. After unpacking, then the hydroponics farm can use it as a plant substrate for growing vegetables.
These cellulose-based cubes are more advanced than they may appear. They will make it possible to grow moon salad and other food plants on the Moon. Photo: Galina Simonsen/SINTEF
Fertilizing Lunar Salad Plants
Okay, so the cellulose packing material solves one problem. But, how do you fertilize Moon plants? There’s not a lot of material on the Moon to make chemical fertilizers often used on Earth farms. Some nutrients might be available in lunar regolith, but not enough to sustain large numbers of farms. So, lunar explorers will turn to a tried-and-true method of providing nutrients for the farm: recycled urine. Mix pee with water and you get “liquid gold” that can keep plants healthy and growing. That makes it pretty valuable as a fertilizer. It can provide nitrogen, potassium, and phosphorous.
These lettuce plants have been grown in a ‘soil’ made of cellulose, with human urine as fertilizer. SINTEF researchers suggest a similar growth method for moon salad and other plant foods. Photo: Jana Pavlova
However, people don’t usually use urine as a fertilizer for food plants here on Earth. That’s because of the fear of spreading disease. And, there are other problems. “Barriers linked to the use of urine as a fertilizer include the strict regulations governing the use of human waste in food plant cultivation”, said Simonsen. “In addition, the handling of human urine is generally unpleasant, combined with the odor and the fact that it releases long-lived organic environmental toxins and trace metals.”
Those aren’t insurmountable problems, however. If urine recycling helps cultivate salad plants, lunar farmers can also grow other edible plants that can assist with the regulation of both the water quality and nutrient balance in the system, according to Simonsen. Plants grown in a future type of lunar “liquid gold” need to be analyzed carefully, she pointed out. “That’s so that we can identify safe threshold values with a view to approving their use as a food source. Moreover, the plants themselves have to contain sufficient nutrients.”
Applying Moon Salad Lessons Learned to Earth Gardens
The idea of using the cellulose base for plant propagation on the Moon comes from technology used in oil and gas transport here on Earth, according to Simonsen. “The methods we apply for fluid hydrocarbon transport in major installations can be transferred to the mechanisms working in minute structures such as these plant substrates”, she said. “Our aim is to construct a digital model that simulates the different factors that influence the behavior of the substrate”, explained Simonsen. “This will enable us to run simulations under conditions that are identical to those on the Moon, including the effect of weightlessness”, she says.
It turns out that the same technologies, including the reuse of urine-based “liquid gold” will be useful in more arid regions here at home. “This method of cultivation can be applied anywhere,” she said, “and is particularly important in the context of resource utilization. Urine contains phosphorous, which is a non-renewable resource, and rockwool, which is currently used in a number of situations, is not biodegradable.”
Simonsen and others hope to apply these methods to the upcoming Artemis missions to the Moon. That and other trips are the first steps toward long-term exploration and habitation of the lunar surface.
Supernovae are incredibly common in the universe. Based on observations of isotopes such as aluminum-26, we know that a supernova occurs on average about every fifty years in the Milky Way alone. A supernova can outshine a galaxy, so you wouldn’t want your habitable planet to be a few light years away when it goes off. Fortunately, most supernovae have occurred very far away from Earth, so we haven’t had to concern ourselves with wearing sunscreen at night. But it does raise an interesting question. When it comes to supernovae, how close is too close? As a recent study shows, the answer depends on the type of supernova.
There is geological evidence that supernovae have occurred quite close to Earth in the past. The isotope iron-60 has a half-life of just 2.6 million years, and it has been found in ocean floor sediment laid down about 2 million years ago. It has also been found in Antarctic ice cores and lunar regolith, suggesting a supernova event around that time. Samples of Earth’s crust point to evidence of another supernova event around 8 million years ago. Both of these would likely have occurred within a few hundred light years of Earth, perhaps as close as 65 light years. Neither of these supernovae seems to have triggered a planet-wide mass extinction, so you might think any supernova more distant than 100 light years is harmless.
The habitable zone for the Milky Way galaxy. Credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)
This new study suggests otherwise. Earlier studies focused on two dangerous periods of a supernova: the overall brightness of the initial explosion reaching a planet at the speed of light, and the stream of energized particles that can strike the planet hundreds or thousands of years later. Both of these tend to have weak effects over hundreds of light years. A nearby supernova might outshine the Moon for a time, which would affect the nocturnal patterns of some creatures, but it wouldn’t trigger mass extinctions. Likewise, our atmosphere is a good barrier to cosmic rays, thus a burst of them for a time is relatively harmless. But this study looked specifically at X-ray light emitted by some supernova, and this is where things can get worse.
X-rays are particularly good at disrupting things like ozone. A strong beam of X-rays from a supernova could strip the ozone layer from a planet like Earth, leaving it open to ultraviolet radiation from its Sun. The ultraviolet light could trigger the creation of a smog layer of nitrogen dioxide, which would lead to acid rain and a wide-scale de-greening of the planet.
The habitable zone for the Milky Way galaxy depends on several factors. Credit: Lineweaver, et al
So the lethal distance of a supernova depends not only on its proximity to a habitable planet but also on the level of X-rays it generates. The team looked at the X-ray spectra of nearly three dozen supernovae over the last 45 years and calculated the lethal distance for each of them. The most harmless was the popular 1987a supernova, which was safe within a light-year or so. The most potentially deadly was a supernova named 2006jd, which could kill a habitable planet from up to 160 light years away.
To be clear, there is no nearby star that poses a potential threat to Earth, not even Betelgeuse. But this study helps us better define where habitable planets might survive in our galaxy. Just as a habitable planet can’t be too close to its star, a planetary system can’t be too close to areas where supernovae are most common, such as the center of our galaxy.
Weiren Wu, the Chief Designer of the Chinese Lunar Exploration Program (CLEP), recently announced an ambitious plan to put Chinese footprints on the lunar surface by 2030. This announcement came on the heels of this year’s Space Day of China, an annual event celebrated on April 24th meant to showcase the space industry achievements of the China National Space Administration (CNSA).
“By 2030, the Chinese people will definitely be able to set foot on the moon. That’s not a problem,” Wu said in an interview with China Media Group (CMG). This most recent announcement comes less than a year after CLEP was given state permission by China to begin Phase-4 of CLEP, whose program structure consists of four phases of robotic lunar exploration, with the first three phases having achieved a flawless success rate.
Phase 1 consisted of two missions, the first of which, the Chang’e-1 lunar orbiter, was the first Chinese lunar mission and was launched in October 2007. After a successful mission it intentionally crashed into the Moon in March 2009. The second mission was the Chang’e-2 lunar orbiter that was launched in October 2010, and after a successful primary mission in lunar orbit the mission was extended to explore the asteroid, 4179 Toutatis, which it successfully conducted in December 2012. Contact with the spacecraft was lost in 2014.
Phase 2 consisted of three missions, the first of which was combination lunar lander and rover, Chang’e-3, that launched in December 2013 and is currently active. The second mission was Queqiao-1, which was launched in May 2018 to serve as a relay satellite sent to the Earth-Moon L2 Lagrange Point for communications relay with Chang’e-4, which was launched in December 2018 and was a combination lunar lander and rover, the latter of which was dubbed Yutu-2. This also marked the first soft landing on the far side of the Moon in history.
Image of the Yutu-2 rover traversing away from the Chang’e-4 lander in January 2019. (Credit: China National Space Administration)
Phase 3 consisted of two missions, the first the experimental test flight, Chang’e-5 T1, which was launched in October 2014 and was designed to test the various rendezvous and capsule technologies that would be required for a lunar sample return mission, which was accomplished with Chang’e-5 in late 2020 as it successfully returned 1731 grams of lunar regolith to the Earth.
Phase 4 will consist of four missions, the first of which will be the Queqiao-2 relay satellite that is scheduled to be launched in 2024 and will act in the same manner as its predecessor for remaining Phase 4 lunar missions, Chang’e-6, -7, and -8, which are scheduled to be launched in May 2024, 2026, and 2028, respectively.
“There’s a relay satellite up there, whose main function is to solve the communication problem between the Earth and them, and also support Chang’e-7 and Chang’e-8, as they will land in different locations,” said Wu.
Wu also discussed how Chang’e-6, slated to be another lunar sample return mission, will be both collecting and returning lunar samples from the far side of the Moon in 2024. He notes this will be the first time in history that lunar samples from the far side of the Moon will be returned to Earth. The Chang’e-7 mission will travel to the south pole of the Moon with the primary objective of searching for hints of water that might be located there.
“We hope to find water there. If water is ever found, it would be great news for human survival on the moon,” said Wu.
In the final mission of Phase Four, Chang’e-8 will work in conjunction with Chang’e-7 to establish the framework for constructing a future lunar research station near the lunar south pole which will be used to better understand in situ resource utilization, also known as ISRU, on the Moon.
Wu also unveiled China’s ambitious goal of establishing a Moon-centered deep space internet to assist in future lunar missions, as well.
“We are building a satellite constellation around the moon, a system that can provide communication, navigation, and remote sensing services. After that, we can carry out future deep space exploration,” said Wu.
While the CNSA has already established a well-executed lunar exploration program along with a blueprint for the coming years, Wu discussed establishing an international lunar research station, also called ILRS, with the goal of completing the outpost’s basic structure by 2030, and he emphasized that China is open to inviting international scientists and partners to take part in the project.
Image from a video animation showing the lunar research station discussed by the CLEP Chief Designer, Weiren Wu. (Credit: China Media Group)
“The international lunar research station built by China is open (to international partners),” Wu said. “We welcome the participation of developed countries such as the United States and European countries. We also hope that BRICS countries and some underdeveloped African countries will join us. We have put forward an initiative for all to sign contracts, deals or strategic agreements of intent.”
Along with making incredible strides in lunar exploration, China also has an active space station, Tiangong, which is a four-module platform in low Earth orbit with the third and most recent module, Mengtian, being launched in October 2022.
When there’s a permanent base on the Moon, astronauts will need a way to replenish their oxygen supply. Fortunately, there’s an almost infinite amount of oxygen in the surrounding regolith, locked up the rocks and soil. The key would be to figure out a cost-effective way to extract it.
Now, NASA has demonstrated that they can harvest oxygen from the lunar regolith, even in the vacuum conditions of space. They used a device called a carbothermal reactor to successfully extract oxygen from a simulated lunar regolith, while also simulating the heat that would be produced by a solar energy concentrator.
While oxygen has previously been extracted from lunar regolith simulant, this was the first time the extraction was performed in a vacuum environment, inside one of the vacuum chambers at Johnson Space Center in Houston, Texas. NASA says this demonstration helps pave the way for lunar astronauts to be able to incorporate in-situ resource utilization by being able to use the resources in the lunar environment,
“This technology has the potential to produce several times its own weight in oxygen per year on the lunar surface, which will enable a sustained human presence and lunar economy,” said Aaron Paz, NASA senior engineer project manager of the Carbothermal Reduction Demonstration (CaRD) team at JSC.
Carbothermal Reduction Demonstration (CaRD) test team in front of the vacuum chamber used to conduct the test. From left: Bill Heausler (JSC), Bill Holton (JSC), Matt Green (JSC), Maggie Meller (JSC), Wayne Smith (JSC), Desmond O’Connor (JSC), Todd Peters (JSC), John Lauterbach (JSC), Anastasia Ford (JSC), Janine Captain (KSC), Te’Sean Pemberton (JSC), Aaron Paz (JSC), David Reinderknecht (KSC), Jeff Michel (JSC), Malay Shah (KSC), Mike Reddington (JSC), Nilab Azim (KSC)
Although the process of heating the regolith is relatively straightforward, NASA needed to be able to mimic the vacuum conditions of space while using the kind of power that would be available to future lunar explorers.
A carbothermal reactor uses the process of heating materials to release any embedded oxygen. Carbothermal reduction has been used for decades on Earth to produce items like solar panels and steel by producing carbon monoxide or dioxide using high temperatures.
The CaRD team test was performed inside a special spherical chamber with a 4.5 meter (15-foot) diameter called the Dirty Thermal Vacuum Chamber. The chamber is considered “dirty” because the samples don’t have to be sterile.
Illustration of a construction technology system on the Moon.
Credit: ICON/BIG-Bjarke Ingels Group
The team used a high-powered laser to simulate heat from a solar energy concentrator and melted the lunar soil simulant within a carbothermal reactor developed for NASA by Sierra Space Corporation.
In a press release, NASA said that after the soil was heated, the team was able to detect oxygen and carbon monoxide using a device called the Mass Spectrometer Observing Lunar Operations (MSolo).
One of the next steps is to perform a test like this on the Moon, using actual lunar regolith. Two upcoming robotic missions to the Moon’s South Pole will carry devices similar to MSolo: the Polar Resources Ice Mining Experiment-1 (PRIME-1) will be the first mission designed to harvest water ice from the Moon. It will use a drill and MSolo will evaluate the drill cuttings for water, oxygen and other chemical compounds. For this mission, NASA has selected the commercial space company Intuitive Machines to set down a lander on the lunar south pole. The current launch date is targeted for June of this year, 2023.
An artist’s concept of the completed design of NASA’s Volatiles Investigating Polar Exploration Rover, or VIPER. VIPER will get a close-up view of the location and concentration of ice and other resources at the Moon’s South Pole. Credits: NASA/Daniel Rutter
The second mission, NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) is set to launch in November 2024 that will explore Mons Mouton, a large flat-topped mountain inside a crater at the Moon’s south pole, to get a close-up view of the location and concentration of water ice and other potential resources. The golf-cart-sized rover is due to be sent to the Moon by a SpaceX Falcon Heavy rocket in late 2023, as the primary payload on Astrobotic’s Griffin robotic lunar lander.
Through MUREP, NASA provides expert guidance and financial assistance via competitive awards to Minority Serving Institutions (MSIs), which are announced annually through a MUREP Partnership Learning Annual Notification (MPLAN). NASA has teamed up with the leading crowdsourcing platform HeroX for this year’s MUREP opportunity and is awarding multiple prizes of $50,000 to MSIs for innovative ideas and action plans for commercialization that will advance NASA’s Mission Directorate priorities.
Historically, what is generally termed “invisible barriers” have prevented MSIs from engaging in partnerships and collaborations with NASA. The MPLAN aims to reduce these barriers by offering competitive awards to Historically Black Colleges and Universities (HBCUs), Indigenous Tribally-Controlled Colleges and Universities (TCUs), Hispanic-Serving Institutions (HSIs), Asian American and Native American Pacific Islander Serving Institutions (AANAPISIs), Alaska Native-Serving and Native Hawaiian-Serving Institutions (ANNHs) and other institutions representing minority communities across the U.S.
Through the Artemis Program, NASA intends to establish a program of “sustained lunar exploration and development” that will enable crewed missions to Mars. Credits: NASA
Through participation in these activities, NASA gains valuable insight and ideas from a broader community, while MSIs gain valuable experience that will prepare them for other NASA funding opportunities. This includes NASA’s annual Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) solicitation and the NASA University Leadership Initiative. This year’s MUREP will consist of two phases, which will commence with MSI Principle Investigators (PIs) submitting proposals based on topics provided by NASA MUREP and three NASA Mission Directorates.
Textiles for Extreme Surface Environments and High Oxygen Atmospheres: Due to the electrostatically-charged nature of lunar regolith (aka. “moondust”), it adheres to spacesuits, causes abrasion, and can muck up machinery when transported back to spacecraft (or habitats). NASA is looking for next-generation textiles that will be used in its Exploration Extravehicular Mobility Unit (xeMU) spacesuits to resist this dust’s “sticky” nature.
Sustainable Atmospheric Carbon Dioxide Extraction and Transformation: technology that allows for the capture from the Martian atmosphere and converting it into oxygen gas and other useful products for use by astronauts.
Extended Reality (XR): technology that combines augmented and virtual reality (AR/VR), mixed reality, and hybrid reality technology to provide improved astronaut training, analysis tools, and real-time operations support.
Lunar and Martian Propellant: technologies related to the production, storage, and usage of cryogenic propellant created from Lunar and Martian resources (i.e., liquid hydrogen, oxygen, and methane).
Space Radiation: improved research into the effects of solar and cosmic radiation on astronaut health, in particular how it affects the human brain, body, and organ function, how these differ based on sex, and the development of countermeasures.
Aerospace Spinoffs: ideas that build on NASA’s long history of aeronautical innovation, which has direct applications for the aviation industry and air transportation systems to make it more sustainable and accessible.
Artist’s illustration of the new spacesuit NASA is designing for Artemis astronauts. It’s called the xEMU,, or Exploration Extravehicular Mobility Unit. Credit: NASA
The 2023 MUREP officially opened for Phase I submissions on April 11th. It will remain open until May 30th, and the winners will be announced on June 28th. These teams will be able to compete in Phase 2, where NASA will facilitate communication and meetings between the awardees, MUREP and Mission Directorate representatives, and subject matter experts. This phase will run from July to December 2023, and the winning teams will be awarded up to $50,000 to further develop and mature their proposals. They will also have the chance to engage in future collaborations with NASA.
According to the Challenge page, NASA will select winning submissions based on a combination of scientific and technical merit; experience, qualification, and faculties; and feasibility and reasonableness. In particular, NASA is looking for “proposals that offer the most advantageous research and development (R&D), deliver technological innovation that contributes to NASA’s missions, provides societal benefit, and grows the U.S. economy. In evaluating proposals, NASA prioritizes the scientific and technical merit of the proposal, as well as its feasibility and potential benefit to NASA’s interests.”
It’s a tale as old as time. A cataclysmic event occurs in the universe and releases a tremendous amount of energy in a short period of time. The event then fades into the darkness and the cosmos returns to normal. These short-lived cosmic events are known as transients and include things such as supernovae and gamma-ray bursts. Transients are quite common, but some of them can challenge explanations. Take for example the transient known as ZTF20abrbeie, nicknamed Scary Barbie.
Scary Barbie was first observed in 2020 and was later observed over a range of wavelengths. It’s an unusual transient for two reasons. The first is that it has lasted much longer than typical transients. A fast radio burst can last for seconds. The afterglow of a supernova can be observed for a month, but Scary Barbie has lasted for more than 800 days and continues to be visible. The second is how terrifyingly energetic it is. A supernova can outshine a galaxy, but Scary Barbie is a thousand times more energetic than the brightest supernovae. It’s hard to imagine the scale of this transient.
According to a study being published in The Astrophysical Journal Letters there’s really only one phenomenon that could explain Scary Barbie: A star being consumed by a black hole.[^1] Black holes don’t swallow stars whole. They first rip the star apart in what is known as a tidal disruption event (TDE). The superheated material of the star is captured by the black hole. Based on observations of ZTF20abrbeie, it was likely a TDE involving a 14 solar mass star and a supermassive black hole more massive than 100 million Suns.
Images of the transient ZTF20abrbeie. Credit: Subrayan, et al
One of the strange things about this transient is that it doesn’t seem to be associated with a particular galaxy. That’s unusual since supermassive black holes tend to lurk in galactic centers. But then again, this transient is so unusual it wasn’t immediately recognized. The team only discovered it through an AI software package they developed known as the Recommender Engine For Intelligent Transient Tracking (REFITT). REFITT combs through observational data looking for transients to study. It came across Scary Barbie in public data from Palomar Observatory’s Zwicky Transient Facility. Once they discovered it, the team then gathered data from other observatories.
This work is a great example of how public data and AI data mining can lead to unexpected discoveries. Only by making data publically accessible and developing tools to filter through this information are these discoveries possible. Science works best when everyone can participate, as this latest study shows. Who knows what other amazing things are lurking in public data just waiting to be discovered?
Gravitational wave astronomy is still in its early stages. So far it has focused on the most energetic and distinct sources of gravitational waves, such as the cataclysmic mergers of black holes and neutron stars. But that will change as our gravitational telescopes improve, and it will allow astronomers to explore the universe in ways previously impossible.
Although gravitational waves have many similarities to light waves, one distinct difference is that most objects are transparent to gravitational waves. Light can be absorbed, scattered, and blocked by matter, but gravitational waves mostly just pass through matter. They can be lensed by the mass of an object, but not fully blocked. This means that gravitational waves could be used as a tool to peer inside astronomical bodies, similar to the way X-rays or MRIs allow us to see inside a human’s body.
This is the idea behind a recent study looking at how gravitational waves could be used to probe the Sun’s interior. The Sun is so incredibly hot and dense that light can’t penetrate it. Even light produced in the Sun’s core takes more than 100,000 years to reach the Sun’s surface. Our only information about the Sun’s interior comes from helioseismology, where astronomers study vibrations of the Sun’s surface caused by sound waves within the Sun.
In this new study, the team looks at how the gravitational waves of fast-rotating neutron stars could be used to study the Sun. Although a perfectly smooth rotating object doesn’t create gravitational waves, asymmetrical spinning objects do. Neutron stars can have deformations or mountainous rises caused by their interior heat or magnetic fields. If such a neutron star spins rapidly, it produces a continuous stream of gravitational waves. These gravitational waves are too faint to be observed by current telescopes, but the next generation of gravitational observatories should be able to detect them.
he path of three neutron stars behind the Sun. Credit: Takahashi et al
Since neutron stars are quite common in the galaxy, some of them are positioned such that the Sun passes in front of them from our perspective. Of the more than 3,000 known pulsars, about 500 of them are good candidates for gravitational wave sources, and of those 3 of them are known to pass behind the Sun. The team used the profiles of these three pulsars as a starting point.
Since the Sun is transparent to gravitational waves, the only effect the Sun has on them is through its gravitational mass. As the waves pass through the Sun, they are gravitationally lensed a bit. The amount of lensing depends on the mass of the Sun and the distribution of that mass. The team found that with proper measurements, gravitational wave observations could measure the density profile of the sun with an accuracy of 3 sigma.
The three known pulsars are likely just a tiny fraction of the gravitational wave sources that pass behind the Sun. Most neutron stars have a spin orientation that doesn’t direct radio flashes in our direction, but they could still be used as gravitational probes. There are likely hundreds of fast-rotating neutron stars that pass behind the Sun over the course of a year. So as we are able to observe their gravitational waves, they should give us an excellent view inside our closest star.
There’s a new solar observing facility taking shape in China. It lies far up on a mountain near Mangya City in the Mongol and Tibetan autonomous prefecture of Qinghai. The telescope is reputed to be the world’s first mid-infrared telescope built for accurate measurements of the solar magnetic field.
The new observatory joins a collection of 35 astronomical telescopes—some already in construction and others in planning—arrayed across the grounds of the Lenghu Astronomical Observation base. That’s a reserve located some 4000 meters up in the Quighainan Mountains. It’s run by the National Astronomical Observatories of China and the Chinese Academy of Sciences.
Platform C of an astronomical observatory under construction in Lenghu, Mangya city, Haixi Mongol and Tibetan autonomous prefecture, northwest China’s Qinghai Province. This is where the new solar observatory is under testing. (Photo courtesy of the management bureau of the Lenghu industrial park)
Scientists refer to the Lenghu base as “one of the most Mars-like places on Earth”. That’s largely due to its dry climate, number of sunny days, and clear atmospheric transparency. Those conditions make it a perfect location to do mid-infrared solar observations. The new state-of-the-art facility is now in testing. It should start trial observations within the year. According to Wang Dongguang, chief engineer from the Huairou Solar Observing Station, this telescope is expected to fill an important niche in the world’s solar observatories.
Infrared Challenges
Doing astronomy observations of any kind in the mid-infrared range raises challenges. They require perfect conditions for the equipment to gather the light needed. According to senior engineer Feng Zhiwei, the team has met several key goals. “Scientists solved the challenge of high ambient noises and degraded detector performance they have encountered in solar observations within this range of the infrared band,” Feng pointed out. The solution lies with domestically made detector chips being installed and tested.
Feng also noted that the system is mainly used for monochromatic imaging observations in the infrared band between 8 and 10 microns. This is important when investigating the mechanism of mass and energy transfer during violent eruptions.
Solar Activity in the Infrared
The infrared range of the electromagnetic spectrum is quite useful for studies of the Sun. Some wavelengths in that range are relatively easy to observe from the ground. Those are in the so-called “infrared atmospheric window” that admits infrared light roughly between 8 and 14 microns. Depending on conditions, light passes through our atmosphere without getting absorbed by the atmospheric gases and water vapor.
However, things get tougher when astronomers want to look at wavelengths beyond that window. The atmosphere absorbs other ranges of infrared light, and it also emits its own infrared. That makes observations tougher to get. To obtain good infrared “seeing”, facilities need to be located near the summits of mountains in dry climates. The telescopes in Hawai’i and Chile and the mountains of China are good examples of facilities that take advantage of high-altitude conditions.
According to scientists from the Chinese Academy of Sciences, this new facility will provide a more accurate study of the Sun’s magnetic field. It will also furnish mid-infrared imaging and spectral observation data. They hope it will achieve major breakthroughs in solar physics with their in-depth studies of the solar magnetic field. The science teams plan to use it to study the mechanism of the generation, accumulation, triggering, and energy release of magnetic energy. Its long-term observations should provide insight into the transfer of matter and energy during violent eruptions such as flares.
The Sun’s magnetic field in a narrated tour that spans from visible to ultraviolet light and includes magnetograms. Courtesy NASA Goddard Space Flight Center Science Visualization Studio.
Adding in a New Solar Facility
China’s new mid-infrared-enabled solar observatory joins a worldwide collection of telescopes aimed at our star. There’s the newly opened Daniel K. Inouye facility in Hawai’i, which is doing science aimed at understanding the fundamental processes and activities in the Sun. Of course, there’s a slew of orbiting and space-based solar telescopes out there. NASA’s Parker Solar Probe dances close to the Sun during its approaches. Other facilities, such as China’s ASO-S solar observatory, the NASA STEREO mission, the NASA/ESA Solar and Heliospheric Observatory, Solar Dynamics Observatory, and ESA’s Solar Observer, are giving long-term looks at the Sun from various orbits, and in many cases, provide early warning of solar activity.
Wang stated that the AIMS telescope is not only innovative in its scientific goals by global standards but also provides other breakthroughs. The research and development of the telescope promote the continued research into infrared spectrum and infrared polarization measurement technology in China.
Scientists at CAS aim to have it be among the pre-eminent astronomy locations in the world and they want to protect its access to the sky. The astronomy “preserve” will have environmental protections from pollution and other interference. Among the 35 telescopes planned, four are now in use. Another 28 have completed the construction of observation towers and dome installation. The rest are in the research and development stages over the next year.
