It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, November 15, 2024
SPACE/COSMOS
Five galaxy portraits by the Italian VST telescope
Five extraordinary galaxies are portrayed in new, glorious images by the VST, a telescope managed by the Italian National Institute for Astrophysics (INAF) at the ESO Paranal observatory, Chile
Istituto Nazionale di Astrofisica
Image of the irregular dwarf galaxy Sextans A, located at a distance of about 4 million light years from us, towards the edge of the Local Group, captured by the VST (VLT Survey Telescope), an Italian telescope managed by the Italian National Institute for Astrophysics (INAF) at ESO’s Paranal Observatory, Chile.view more
Image of the irregular galaxy NGC 3109, located at a distance of about 4 million light years from us, towards the edge of the Local Group, captured by the VST (VLT Survey Telescope), an Italian telescope managed by the Italian National Institute for Astrophysics (INAF) at ESO’s Paranal Observatory, Chile.
Image of the irregular galaxy NGC 5253, located at a distance of about 11 million light years from us, captured by the VST (VLT Survey Telescope), an Italian telescope managed by the Italian National Institute for Astrophysics (INAF) at ESO’s Paranal Observatory, Chile.
Image of the spiral galaxy known as Southern Pinwheel (also referred to as NGC 5236 or M 83), located at a distance of about 15 million light years from us, captured by the VST (VLT Survey Telescope), an Italian telescope managed by the Italian National Institute for Astrophysics (INAF) at ESO’s Paranal Observatory, Chile.
Image of the spiral galaxy IC 5332, located at a distance of about 30 million light years from us, captured by the VST (VLT Survey Telescope), an Italian telescope managed by the Italian National Institute for Astrophysics (INAF) at ESO’s Paranal Observatory, Chile.
Credit: INAF/VST-SMASH/C. Tortora et al. (2024)
Article Title
VST-SMASH: the VST survey of Mass Assembly and Structural Hierarchy
The ISS Is Leaking Air—And NASA and Russia Can’t Agree Why
NASA elevated the air leak to the highest level of risk, but Russia isn't convinced it's that serious.
For the past five years, air has been escaping through a Russian section of the International Space Station (ISS) at an increasing rate. NASA and its Russian counterpart, Roscosmos, are still in disagreement over the root cause of the leak, as well as the severity of the consequences.
The leak was first discovered in 2019 in the vestibule (named PrK) that connects a docking port to the Russian Zvezda module, which Roscosmos had launched to low Earth orbit in July 2000. Earlier this year, NASA elevated the leak to the highest level of risk as the rate of air escaping from the module had doubled from one pound of air per day to a little over two pounds.
“While the Russian team continues to search for and seal the leaks, it does not believe catastrophic disintegration of the PrK is realistic,” Bob Cabana, a former NASA astronaut who now chairs the ISS Advisory Committee, said during a meeting on Wednesday, SpaceNews reported. “NASA has expressed concerns about the structural integrity of the PrK and the possibility of a catastrophic failure.”“The Russians believe that continued operations are safe but they can’t prove to our satisfaction that they are…”
“The Russians believe that continued operations are safe but they can’t prove to our satisfaction that they are, and the U.S. believes that it’s not safe but we can’t prove to the Russians’ satisfaction that that’s the case,” he added.
Russian teams believe the air leak was likely caused by high cyclic fatigue from micro vibrations, while teams at NASA think pressure and mechanical stress, residual stress, material properties of the module, and environmental exposure are all at play, according to SpaceNews.
The air leak was addressed in a recent report by NASA’s Office of Inspector General (OIG), which highlighted its true severity and the risk it poses to the crew. The OIG report stated that the two space agencies can’t seem to agree on the point at which the leak should be considered unsustainable. NASA and Roscosmos met to discuss the ISS air leak, with NASA officials noting that Roscosmos “is confident they will be able to monitor and close the hatch to the Service Module prior to the leak rate reaching an untenable level,” according to the report.
“Although the teams continue to investigate the causal factors for the crack initiation and growth, the U.S. and Russian technical teams don’t have a common understanding of what the likely root cause is or the severity of the consequences of these leaks,” Cabana is quoted in SpaceNews as saying.
The rate of air leaking from the hole increased around a week before the February 14 launch of the Progress MS-26 cargo spacecraft, which docked to the aft end of Zvezda. The hatch that connects the module to the ISS remained open for five days as the crew offloaded the cargo from Progress MS-26 onto the space station, but was closed shut afterwards.
NASA and Roscosmos are currently monitoring the leak and preparing to close the hatch to the service module when access is not required in order to minimize the amount of air lost and isolate the leak itself from the rest of the space station. If required, the space agencies are prepared to permanently shut off the hatch should the leak rate became unmanageable. The ISS would function normally, but there would be one less docking port for spacecraft delivering cargo to the space station.
As the two space agencies continue to discuss the potential risk, the aging space station is inching closer to retirement within the next six years and its hardware may finally be giving in to the wear and tear of the harsh space environment.
Chinese discovery on dark side of the Moon
When Chinese scientists sent a robot down to the surface, they found something exciting in the soil.
This image shows the dark side of the moon that can never be seen from Earth. Source: Deep Space Climate Observatory/NASA
A Chinese space exploration robot sent to the dark side of the Moon has found evidence the surface was once peppered with active volcanoes. During the 53-day Chang'e 6 mission, soil was gathered using the lander’s scoop and drill.
The samples were then analysed and testing revealed fragments of basalt, a type of volcanic rock. This provided clear evidence the volcanoes were active 2.8 billion years ago, but one outlying sample was dated at 4.2 billion years, indicating they remained active for a sustained period.
Earth is around 4.5 billion years old, and the earliest evidence of life on our planet is fossilised microorganisms from around 3.7 billion years ago
The Moon is believed to have formed just a few million years after the Earth did. The leading theory is that it was created after Earth and a small planet around the size of Mars collided. The debris was then caught in our orbit, forming a moon.
After its creation, the Moon was a sea of glowing molten rock and its red surface likely appeared much larger in the sky.
By the time the volcanoes had formed, the surface of the Moon had cooled and turned grey. But the large empty lunar seas that we can see today, would have still been filled with glowing lava from the volcanoes.
Moon could have appeared different to dinosaurs
Before the Chang'e 6 mission, it had only been established that volcanoes existed on the near side of the moon between 2 and 4 billion years ago. The most recent mission used lead isotopes to determine the age of 108 basalt fragments.
Evidence gathered during the Chang'e 5 mission in 2020 suggests some volcanoes persisted on the near side of the Moon until 120 million years ago. This means it could have appeared quite different when dinosaurs roamed the Earth during the Cretaceous period.
The research was conducted by the Chinese Academy of Sciences and published in the journal Nature.
Telescope for NASA’s Roman Mission complete, delivered to Goddard
NASA/Goddard Space Flight Center
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Upon arrival at NASA's Goddard Space Flight Center, the Optical Telescope Assembly for the agency's Nancy Grace Roman Space Telescope was lifted out of the shipping fixture and placed with other mission hardware in Goddard's largest clean room. Now, it will be installed onto Roman's Instrument Carrier, a structure that will keep the telescope and Roman's two instruments optically aligned. The assembly's electronics box –– essentially the telescope's brain –– will be mounted within the spacecraft along with Roman's other electronics.
NASA’s Nancy Grace Roman Space Telescope is one giant step closer to unlocking the mysteries of the universe. The mission has now received its final major delivery: the Optical Telescope Assembly, which includes a 7.9-foot (2.4-meter) primary mirror, nine additional mirrors, and supporting structures and electronics. The assembly was delivered Nov. 7. to the largest clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where the observatory is being built.
The telescope will focus cosmic light and send it to Roman’s instruments, revealing many billions of objects strewn throughout space and time. Using the mission’s Wide Field Instrument, a 300-megapixel infrared camera, astronomers will survey the cosmos all the way from the outskirts of our solar system toward the edge of the observable universe. Scientists will use Roman’s Coronagraph Instrument to test new technologies for dimming host stars to image planets and dusty disks around them in far better detail than ever before.
“We have a top-notch telescope that’s well aligned and has great optical performance at the cold temperatures it will see in space,” said Bente Eegholm, optics lead for Roman’s Optical Telescope Assembly at NASA Goddard. “I am now looking forward to the next phase where the telescope and instruments will be put together to form the Roman observatory.”
Designed and built by L3Harris Technologies in Rochester, New York, the assembly incorporates key optics (including the primary mirror) that were made available to NASA by the National Reconnaissance Office. The team at L3Harris then reshaped the mirror and built upon the inherited hardware to ensure it would meet Roman’s specifications for expansive, sensitive infrared observations.
“The telescope will be the foundation of all of the science Roman will do, so its design and performance are among the largest factors in the mission’s survey capability,” said Josh Abel, lead Optical Telescope Assembly systems engineer at NASA Goddard.
The team at Goddard worked closely with L3Harris to ensure these stringent requirements were met and that the telescope assembly will integrate smoothly into the rest of the Roman observatory.
The assembly’s design and performance will largely determine the quality of the mission’s results, so the manufacturing and testing processes were extremely rigorous. Each optical component was tested individually prior to being assembled and assessed together earlier this year. The tests helped ensure that the alignment of the telescope’s mirrors will change as expected when the telescope reaches its operating temperature in space.
Then, the telescope was put through tests simulating the extreme shaking and intense sound waves associated with launch. Engineers also made sure that tiny components called actuators, which will adjust some of the mirrors in space, move as predicted. And the team measured gases released from the assembly as it transitioned from normal air pressure to a vacuum –– the same phenomenon that has led astronauts to report that space smells gunpowdery or metallic. If not carefully controlled, these gases could contaminate the telescope or instruments.
Finally, the telescope underwent a month-long thermal vacuum test to ensure it will withstand the temperature and pressure environment of space. The team closely monitored it during cold operating conditions to ensure the telescope’s temperature will remain constant to within a fraction of a degree. Holding the temperature constant allows the telescope to remain in stable focus, making Roman’s high-resolution images consistently sharp. Nearly 100 heaters on the telescope will help keep all parts of it at a very stable temperature.
“It is very difficult to design and build a system to hold temperatures to such a tight stability, and the telescope performed exceptionally,” said Christine Cottingham, thermal lead for Roman’s Optical Telescope Assembly at NASA Goddard.
Now that the assembly has arrived at Goddard, it will be installed onto Roman’s Instrument Carrier, a structure that will keep the telescope and Roman’s two instruments optically aligned. The assembly’s electronics box –– essentially the telescope’s brain –– will be mounted within the spacecraft along with Roman’s other electronics.
With this milestone, Roman remains on track for launch by May 2027.
“Congratulations to the team on this stellar accomplishment!” said J. Scott Smith, the assembly’s telescope manager at NASA Goddard. “The completion of the telescope marks the end of an epoch and incredible journey for this team, and yet only a chapter in building Roman. The team’s efforts have advanced technology and ignited the imaginations of those who dream of exploring the stars.”
To virtually tour an interactive version of the telescope, visit:
In this photo, optical engineer Bente Eegholm inspects the surface of the primary mirror for NASA's Nancy Grace Roman Space Telescope. This 7.9-foot (2.4-meter) mirror is a major component of the Optical Telescope Assembly, which also contains nine additional mirrors and supporting structures and electronics.
Roman Optical Telescope Assembly
This photo shows the Optical Telescope Assembly for NASA's Nancy Grace Roman Space Telescope, which was recently delivered to the largest clean room at the agency's Goddard Space Flight Center in Greenbelt, Md.
Credit
NASA/Chris Gunn
NRL completes development of robotics capable of servicing satellites, enabling resilience for the U.S. space infrastructure
Naval Research Laboratory
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After completing testing, the Robotic Servicing of Geosynchronous Satellites (RSGS) payload resides in the cryogenic thermal vacuum chamber at the U.S. Naval Research Laboratory’s Naval Center for Space Technology in Washington, D.C. Oct. 8, 2024. Once on-orbit, the RSGS payload will inspect and service satellites in geosynchronous orbit.
WASHINGTON – U.S. Naval Research Laboratory (NRL) Naval Center for Space Technology (NCST) in partnership with Defense Advanced Research Projects Agency (DARPA) successfully completed development of a spaceflight qualified robotics suite capable of servicing satellites in orbit, Oct. 8.
Under DARPA funding, NRL developed the Robotic Servicing of Geosynchronous Satellites (RSGS) Integrated Robotic Payload (IRP). This transformative new space capability was delivered to DARPA’s commercial partner, Northrop Grumman’s SpaceLogistics, for integration with its spacecraft bus, the Mission Robotics Vehicle (MRV).
“The recent completion of thermal vacuum testing marks a major milestone toward achieving the program’s goal of demonstrating robotic servicing capabilities on orbit in the near future,” said NRL Director of Research Dr. Bruce Danly. “NRL’s contributions to the robotic payload are an essential part of realizing this vision, which promises to transform satellite operations in geostationary orbit, reduce costs for satellite operators, and enable capabilities well beyond what we have today. In fact, the anticipated capabilities are potentially revolutionary for both national security and civil applications.”
As DARPA’s robotic payload developer for the RSGS program, NRL looked to the future to design, build, integrate, and test groundbreaking satellite servicing capabilities.
“This collaboration unlocks new servicing opportunities for both commercial and government satellites, enabling usual-close inspections, orbital adjustments, hardware upgrades, and repairs,” said Bernie Kelm, NRL NCST superintendent of the Spacecraft Engineering Division. “We’ve created advanced spaceflight hardware and software that will significantly enhance satellite servicing operations, including all robotic controls.”
Satellites in geosynchronous orbit, positioned approximately 22,000 miles above Earth, are crucial for military, government, and commercial communications, Earth-observing science, and national security services.
Currently, spacecraft face significant challenges, in part because of the inability to perform in-orbit repairs or upgrades. To compensate for the lack of servicing options, satellites are often loaded with backup systems and excess fuel, leading to increased complexity, weight, and cost. Should this project prove successful, satellites can receive in-orbit upgrades based on new technology to extend their service life, Kelm added.
“The military regularly fixes aircraft, tanks, ships, and trucks that break. We upgrade aircraft and ships with the latest radars, computers, and engines,” said Glen Henshaw, Ph.D., NRL senior scientist for Robotics and Autonomous Systems. “Satellites are the only expensive equipment we buy that can’t be repaired or upgraded once they are in the field, and this costs the taxpayer money. RSGS is intended to change this situation; we intend to demonstrate that we can upgrade and repair these valuable assets using robots.”
Thermal Vacuum (TVAC) Testing Process The test campaign put the robotic payload through its paces across the range of temperatures it will face while on-orbit and under vacuum conditions similar to space. Engineers tested all aspects of the payload including avionics, cameras, and lights, and demonstrated all operations, with each of its two robotic arms including launch lock deployments, calibrations, and tool changing. The test also verified SpaceWire communications and robotic compliance and visual servo control modes.
“NRL’s Team RSGS has spent nearly 10 years focused on the goal of completing this first of a kind, robotic servicing payload,” said William Vincent, NRL RSGS program manager. “The completion of IRP TVAC represents a huge milestone and countless hours of work from an incredible group of dedicated personnel. Like sending a child off to college for the first time, shipping the IRP to Dulles is a bittersweet experience.”
NRL worked for over two decades to mature the technology enabling the RSGS program. RSGS is designed to safely and reliably repair and upgrade valuable commercial, civil, and national security satellites, some of which cost over a billion dollars. In the near future, robotic satellite “mechanics” may extend the useful life of satellites by upgrading a variety of capabilities including new electronics, propulsion, and sensors capabilities. RSGS robots could demonstrate broad servicing as a precursor to building large structures in-orbit which could include the next great observatory, solar power stations, or other revolutionary new systems.
“We hope that this will eventually lead to spacecraft that are more modular and easier to maintain,” Henshaw said.
Following its anticipated 2026 launch on the Northrop Grumman’s MRV spacecraft bus, the robotic payload will undergo initial checkout and calibration with full operational servicing missions to follow.
“We will proudly watch RSGS as it provides resilience for the current U.S. space infrastructure and takes the first concrete steps toward a transformed space architecture with revolutionary capabilities,” Vincent said.
Steven Butcher, Technology Service Corporation space robotics and mechanisms engineer, performs an inspection of the Robotic Servicing of Geosynchronous Satellites (RSGS) payload after completing testing in the cryogenic thermal vacuum chamber at the U.S. Naval Research Laboratory’s Naval Center for Space Technology in Washington, D.C. Oct. 4, 2024. Once on-orbit, the RSGS payload will inspect and service satellites in geosynchronous orbit.
After completing testing, the Robotic Servicing of Geosynchronous Satellites (RSGS) payload resides in the cryogenic thermal vacuum chamber at the U.S. Naval Research Laboratory’s Naval Center for Space Technology in Washington, D.C. Oct. 8, 2024. Once on-orbit, the RSGS payload will inspect and service satellites in geosynchronous orbit.
Credit
U.S. Navy photo by Sarah Peterson
About the U.S. Naval Research Laboratory
NRL has a longstanding relationship with academia and industry as a collaborator, contractor, and through technology transfer partnership mechanisms, such as commercial licensing, Cooperative Research and Development Agreements, and Educational Partnership Agreements.
NRL is a critical link within the Navy’s Research, Development, and Acquisition chain and Naval Research Enterprise. Through NRL, the Navy has direct ties with sources of fundamental ideas in industry and the academic community throughout the world and provides an effective coupling point to the research and development chain for Office of Naval Research. NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL is located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.
For more information, contact NRL Corporate Communications at (202) 480-3746 or nrlpao@us.navy.mil.
Long-sought measurement of exotic beta decay in thallium helps extract the timescale of the Sun’s birth
Have you ever wondered how long it took our Sun to form in its stellar nursery? An international collaboration of scientists is now closer to an answer. They succeeded in the measurement of the bound-state beta decay of fully-ionised thallium (205Tl81+) ions at the Experimental Storage Ring (ESR) of GSI/FAIR. This measurement has profound effects on the production of radioactive lead (205Pb) in asymptotic giant branch (AGB) stars and can be used to help determine the Sun’s formation time. The results have been published in the journal Nature.
Current calculations estimate that the formation of our Sun from the progenitor molecular cloud took about a few tens of million years. Scientists derive this number from long-lived radionuclides produced just before the Sun’s formation by what is called the astrophysical s-process. The s-process had operated in the solar neighborhood in asymptotic giant branch (AGB) stars — intermediate mass stars at the end of their burning cycles. The radionuclides, all long decayed since the birth of the Sun 4,6 billion years ago, left their imprints as small excess abundances of the decay products in meteorites where they can now be detected. The ideal candidate is a radionuclide that is purely produced by the s-process and does not have pollutions from other nucleosynthesis processes. The “s-only” nucleus 205Pb is the sole candidate that fulfils these properties.
On Earth, it is atomic 205Pb that decays to 205Tl by converting one of its protons and an atomic electron into a neutron and an electron neutrino. The energy difference between 205Pb and its daughter 205Tl is so tiny that the larger binding energies of the electrons in 205Pb (with charge Z=82 compared to only 81 electrons in 205Tl) tip the scale. In other words, if all electrons are removed the role of daughter and mother in the decay is inverted, and 205Tl undergoes a beta minus decay to 205Pb. This is what happens in AGB stars where the temperatures of a few 100 million Kelvin are sufficient to fully ionize the atoms. The amount of 205Pb being produced in AGB stars depends crucially on the rate at which 205Tl decays to 205Pb. But this decay cannot be measured under normal laboratory conditions because there 205Tl is stable.
The decay of 205Tl is only energetically possible if the produced electron is captured into one of the bound atomic orbits in 205Pb. This is an exceptionally rare decay mode known as bound-state beta decay. Moreover, the nuclear decay leads to an excited state in 205Pb which is situated only by minuscule 2.3 kiloelectronvolt above the ground state but is strongly favored over the decay to the ground state. The 205Tl-205Pb pair can be imagined as a stellar seesaw model, as both decay directions are possible, and the winner depends on the stellar environment conditions of temperature and (electron) density — and on the nuclear transition strength which was the great unknown in this stellar competition.
This unknown has now been unveiled in an ingenious experiment conducted by an international team of scientists coming from 37 institutions representing twelve countries. Bound-state beta decay is only measurable if the decaying nucleus is stripped of all electrons and is kept under these extraordinary conditions for several hours. Worldwide this is only possible at the GSI/FAIR heavy-ion Experimental Storage Ring (ESR) combined with the fragment separator (FRS). “The measurement of 205Tl81+ had been proposed in the 1980s, but it has taken decades of accelerator development and the hard work of many colleagues to bring to fruition,” says Professor Yury Litvinov of GSI/FAIR, spokesperson of the experiment. “A plethora of groundbreaking techniques had to be developed to achieve the required conditions for a successful experiment, like production of bare 205Tl in a nuclear reaction, its separation in the FRS and accumulation, cooling, storage and monitoring in the ESR.”
“Knowing the transition strength, we can now accurately calculate the rates at which the seesaw pair 205Tl-205Pb operates at the conditions found in AGB stars,” says Dr. Riccardo Mancino, who performed the calculations as a post-doctoral researcher at the Technical University of Darmstadt and GSI/FAIR.
The 205Pb production yield in AGB stars has been derived by researchers from the Konkoly Observatory in Budapest (Hungary), the INAF Osservatorio d'Abruzzo (Italy), and the University of Hull (UK), implementing the new 205Tl/205Pb stellar decay rates in their state-of-the-art AGB astrophysical models. “The new decay rate allows us to predict with confidence how much 205Pb is produced in AGB stars and finds its way into the gas cloud which formed our Sun,” explains Dr. Maria Lugaro, researcher at Konkoly Observatory. “By comparing with the amount of 205Pb we currently infer from meteorites, the new result gives a time interval for the formation of the Sun from the progenitor molecular cloud of ten to twenty million years that is consistent with other radioactive species produced by the slow neutron capture process.”
„Our result highlights how groundbreaking experimental facilities, collaboration across many research groups, and a lot of hard work can help us understand the processes in the cores of stars. With our new experimental result, we can uncover how long it took our Sun to form 4.6 billion years ago,” says Guy Leckenby, doctoral student from TRIUMF and first author of the publication.
The measured bound-state beta decay half-life is essential to analyze the accumulation of 205Pb in the interstellar medium. However, other nuclear reactions are also important including the neutron capture rate on 205Pb for which an experiment is planned utilizing the surrogate reaction method in the ESR. These results clearly illustrate the unique possibilities offered by the heavy-ion storage rings at GSI/FAIR allowing to bring the Universe to the lab.
The work is dedicated to deceased colleagues Fritz Bosch, Roberto Gallino, Hans Geissel, Paul Kienle, Fritz Nolden, and Gerald J. Wasserburg, who were supporting this research for many years.
Artistic depiction of an AGB star mixing with the early Solar System.
"We’re ultimately looking to discover life, and to do so, we have to think outside the box."
NASA's Viking 2 on the surface of Mars. (Image credit: NASA/JPL)
In 1975, NASA's Viking 1 spacecraft entered orbit around Mars, carrying a mission to unlock the secrets of the Red Planet. Soon, it released twin landers that drifted toward the Martian surface and eventually made history as the first American spacecraft to touch down on the world.
For over six years, Viking 1 continued to orbit Mars' Chryse Planitia region while its landers collected soil samples using robotic arms and onboard laboratories, marking a groundbreaking chapter in humanity's exploration of the Martian environment.
At the time, however, little was known about environmental conditions of the Red Planet, and the Viking life detection experiments were modeled after culturing techniques commonly used to identify microbes on Earth. These methods involved adding water and nutrients to those aforementioned soil samples, then monitoring for any signs that suggest microbes might be living in the samples. Such signals were associated with responses to the additives — essentially an influx of components needed to complete normal life cycles as we know them — and included things like growth, reproduction and the consumption of food for energy.
One day, both Viking landers reported a potential positive detection of microbial activity in their soil samples, and the findings naturally sparked decades of intense debate. Had we finally found proof of life elsewhere in the universe? However, most scientists now believe the results were negative or — at best — inconclusive. They think it's more likely that the positive readings have an alternative explanation.
According to Dirk Schulze-Makuch, an astrobiologist at the Technische Universität Berlin in Germany, there may be another facet to this mystery that hasn't yet been considered: Viking may indeed have discovered life on Mars, but the water-based nature of its life-detection experiments might have unintentionally killed it.
In a recent commentary published in the journal Nature Astronomy, titled "We may be looking for Martian life in the wrong place," he argues that because Mars is even drier than one of the most arid places on Earth, the Atacama Desert, where microbes obtain water through salts that draw moisture from the atmosphere, any analogous Martian life would be highly sensitive to the addition of liquid water. Even one drop too much could threaten their existence.
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Yet, the Viking experiments were conducted under the assumption that Martian life would require liquid water, like most life forms on Earth. Thus, Schulze-Makuch believes, the results of the experiments might be best explained not as the absence of organic life, but as the human-driven destruction of arid microbial organisms exposed to too much water.
If the assumptions about organisms thriving in Mars' hyperarid conditions are accurate, Schulze-Makuch argues that NASA should rethink its longstanding "follow the water" strategy for finding life beyond Earth. Instead, he suggests adopting a "follow the salts" approach.
Space.com sat down with Schulze-Makuch to discuss this intriguing take on the Viking experiments, how the community has reacted to it, and what it might mean for life-seeking experiments going forward.
The interview has been edited for length and clarity.
This is the first panoramic view ever returned from the surface of Mars. This view from Camera 2 on Viking 1 shows Chryse Planitia on 20 July 1976, shortly after Viking landed. (Image credit: NASA/JPL)
What sparked your interest in re-examining the Viking experiments on Mars?
I’ve always been intrigued by the Viking life detection experiments. It's unfortunate that they haven’t received more emphasis because, ultimately, they're the only direct life detection experiments we've conducted on another planet. And yes, the results were confusing, but for scientists, that kind of ambiguity is fascinating — it usually signals that there's something deeper to understand.
Now, nearly 50 years later, we can reexamine those experiments with a much better grasp of Mars' environment — its complexities — and how certain reactions could unfold there. We've also gained invaluable insights into extremophiles on Earth — organisms that survive in the most inhospitable conditions — and how they function. That knowledge helps us interpret the Viking data with a new perspective. Why do you think the Viking experiments might have actually encountered and inadvertently killed Martian life?
I did a lot of work in the Atacama Desert, which is an analog environment to Mars. And we got some “Blues Clues” about how organisms survive there. From there, it wasn't that difficult to put it together.
I presented this idea about a year ago at a special meeting on life in the universe, hosted by the King of the Netherlands. Many European Space Agency scientists were there, and I thought afterwards I may get some backlash, but they took it surprisingly well.
The science concept in this case is that salts, and organisms with the help of the salts, can pull water directly from the atmosphere. There’s also an effect where, as water is removed, there’s a sort of delay — a hysteresis — because the system resists crystallization. This means water can remain in a salt longer than expected, which is crucial because it raises the water activity on a microscopic level, making it accessible to microbes. Life is very good at taking advantage of these physical or chemical effects. There are plenty of examples in biology, which is very good at using these kinds of effects — I’d nearly call them tricks because they're using this kind of quirky physics or chemistry.
Of course, I can’t say there’s definitely an organism on Mars exploiting these effects. But Mars, almost 4 billion years ago, was so much like Earth, with abundant water. As it became drier, moving toward its current desert state, these are the kinds of adaptations I’d expect any remaining life to develop. How do organisms in Earth's deserts survive by pulling water out of the salts?
It is the same thing if you think about rice in a salt dispenser, where the rice grains are inside to keep the salt dry — otherwise it would become all clumpy. The rice grains are more hygroscopic than the salt grains, so they attract more water from the atmosphere.
It’s the same thing we see in the Salars, where ancient salt lakes dried up, leaving behind salt deposits, but there is still a little moisture in the atmosphere above these deposits. Depending on the type of salt, it can attract and absorb moisture. We call this process hygroscopicity, and it allows the salt to become damp, eventually forming a brine, which is then called deliquescence.
We see this even with common table salt — it can draw in enough moisture from the air to create a brine, in which certain bacteria thrive, even in fully saturated sodium chloride solutions. While more complex salts like perchlorates or chlorates are tougher environments, some organisms can tolerate fairly high concentrations. The main salt on Mars appears to be sodium chloride, which means this idea could work.
(Image credit: NASA)
Do you believe the assumption that life requires water hinders our understanding of extraterrestrial life and how we look for it?
In general, I would agree with that — but not for Mars. Mars and Earth are so much alike, and you have a lot of the same kind of minerals, though not the same variety on Mars that Earth has because there are a lot of minerals on Earth that are formed by biology. But they are otherwise very, very similar.
They are both terrestrial planets, somewhat similar in their distances away from the sun. If we expect life on Mars, we would be expecting that dependence on water as well. I think if you would look for life, for example, on Titan, where surface conditions vary greatly, then I would agree that this requirement for water would hinder our search. But for Mars itself, I don't see a problem. How might the Viking experiments have led to a false negative result that life doesn't exist on Mars?
Imagine something similar happened to you [as a human]. For example, if there was an alien in a spaceship coming down to Earth and found you somewhere in the desert. Then they said 'OK, look, that's a human and it needs water,' and puts you directly in the middle of the ocean. You wouldn't like that, right? Even though that is what we are. We are water-filled bags, but too much water is a bad thing, and I think that's what happened with the Viking life-detection experiments.
There was one study done in the Atacama Desert where there was torrential rain and it flooded a huge area. Afterwards, the scientists found that 70-80% of the indigenous bacteria died because they couldn't handle that much water so suddenly. This really fits into the same picture.
How would you design a new experiment that would take this into account and could maybe detect these life forms?
I think the most important thing is that one experiment on its own cannot allow us to make a decision. For example, one might assume that Martian organisms have exactly the same DNA as those on Earth, and so we might devise an experiment to go looking for that material. But what if it’s different? You would then have to have several different experiments to test this out and make a sure conclusion.
In the case of the Viking life-detection experiments, these people were not stupid and I think the approach was right at that time, but the scientists didn't really know anything about the Martian environment. What they were doing was very sophisticated for the time. And now, we have much better tools and much better insights and better methodologies.
I think, from my perspective, the key is not to rely on one experiment to make a conclusion. My research group, for example, is currently working on live detection based on motility, the characteristic movement of microorganisms, which also uses water by the way, but in very small amounts. We look at how the organisms or the sediment particles move in the drop of liquid, for example. If it's a bacterium, it has a certain kind of pattern that depends on the kind of bacteria and can be distinguished from a sediment particle because a sediment particle would move differently. With AI, we can track the movement automatically to say this is a microbe, and that is a sediment particle. We think that we can distinguish even an alien microbe from a sediment particle. That might be an interesting experiment to conduct.
The point is, there are numerous ways to [search for life on Mars]. Ideally, it would be nice to have a microscope on Mars, but this poses challenges — though I think it’s getting to be about time that we use one for searching for life on other planets.
But to make a long story short, we would want to have several different kinds of life-detection methods that are independent of each other, and from there, we could come up with more convincing data.
Taken by the Viking 1 lander shortly after it touched down on Mars, this image is the first photograph ever taken from the surface of Mars. It was taken on July 20, 1976. (Image credit: NASA/JPL)
Have you observed a shift since Viking in how scientists are looking for life on Mars? Have the methods evolved a bit or taken this into account?
Yes, there are lots of different methods available now and there are, of course, advantages and disadvantages to each. Gas chromatography and [mass spectrometry] is one of the more sophisticated [methods] and would allow scientists to look at the organic compositions of samples.
We could then compare to samples from Earth. For example, you would see specific patterns and peaks for certain proteins and their amino acids — these we know and could expect. You could also look for products of abiotic synthesis, the kind that happens in the beginning, before life, and would be indicative with high levels of small organic molecules.
Essentially, we do have quite a few methodologies that would be really interesting to test out. In the context of this hypothesis, what specific salts or mineral compositions could be prioritized? You mentioned sodium chloride, but are there any others?
Yes, you’d need to look for hygroscopic salts. Not all soils possess this property; for instance, some sulfur salts, like gypsum, are not hygroscopic as the mineral structure contains a lot of water and would not be suitable.
Sodium chloride is probably the most common choice, along with potassium chloride. In my research group, we're also looking at chlorates and perchlorates, which we’ve found to be quite effective. Chlorate (ClO₃) and perchlorate (ClO₄) are the types we're interested in, although perchlorates can be a bit problematic for life as we know it; they can be tolerated only in certain amounts, and too much can be harmful. On the other hand, chlorates seem to work much better.
One advantage of chlorates and perchlorates is that they stay liquid at much lower temperatures compared to sodium and potassium chloride. That’s significant because if the environment gets really cold, having salts that remain liquid at colder temperatures could provide a more suitable habitat for microbial life.
So, while sodium chloride is a top priority, I’d also suggest considering chlorates and perchlorates. In regions like the Southern Highlands of Mars, high concentrations of chloride have been detected. Do you think this take is controversial?
Yes, surely it's controversial. In science, challenging the prevailing paradigm is always tough. Colleagues often review work from a position that reflects their existing beliefs, and egos can complicate the process as well. Ultimately, though, I believe science prevails. There isn't a top-down approach; even the most esteemed scientists can be wrong, and we all understand that. My aim has always been to present our findings and let the scientific community engage with them as potential hypotheses.
But it’s important to put out a hypothesis out to see if we can come up with a logically sound solution to it. I do not know whether there are really microbes on Mars, but I feel confident that my proposed solution could work and might reveal life. Future missions should definitely investigate this further. I might be wrong, but I could also be right — we won’t know until we try.
Eventually, we will get the evidence, one way or another, and that's good. I’m ok if I was wrong. I think either way, this was an interesting idea — even if some people don't think so. But we’re ultimately looking to discover life, and to do so, we have to think outside the box.
Summary of evidence showing the unique source and double lens nature of J1721+8842. Credit: arXiv (2024). DOI: 10.48550/arxiv.2411.04177
An international team of astronomers has discovered an instance of two galaxies aligned in a way where their gravity acts as a compound lens. The group has written a paper describing the findings and posted it on the arXiv preprint server.
Prior research has led to many findings of galaxies, or clusters of them, bending light in ways that were predicted by Einstein's theory of general relativity. Astronomers have noted that some of them work as imperfect lenses, distorting the light behind them in interesting ways.
Some researchers have also noted that elliptical galaxies can serve as a lens, serving to brighten the light behind them. In this new effort, the research team has found, for the first time, two galaxies that align in a way that allows their gravity to work as a compound lens.
A compound lens, as its name suggests, is made up of two lenses. Those made artificially are cemented together and work to correct each other's dispersion. In the astronomical case, a compound lens can be made by the dual effects of two galaxies lined up next to one another just right.
The researchers note that when the system, J1721+8842, was first discovered, it was believed that there was just one elliptical galaxy bending the light from a quasar behind it. In analyzing data over a two-year period, the researchers of this new effort found variations in the quasar imagery. They also found small bits of light that, at first glance, appeared to be duplicates from a single source.
A closer look revealed that they matched the light from the main quartet of lights—a finding that showed that all six bits of light were from the same source. Prior research had suggested such an image could be the result of a natural compound lens.
When adding data from the James Webb Space Telescope, the team found that a reddish ring that was mixed with the other lights and was thought to be an Einstein ring was, in reality, a second lensing galaxy. The researchers next built a computer model and used it to confirm that the observation they had made was indeed that of a compound lens.
The research team expects the finding will allow other researchers to more precisely calculate the Hubble constant, perhaps leading to a resolution of conflict over its actual value.
More information: F. Dux et al, J1721+8842: The first Einstein zig-zag lens, arXiv (2024). DOI: 10.48550/arxiv.2411.04177
NASA’s Hubble Sees Aftermath of Galaxy’s Scrape with Milky Way
This artist's concept shows a closeup of the Large Magellanic Cloud, a dwarf galaxy that is one of the Milky Way galaxy's nearest neighbors. Credits: NASA, ESA, Ralf Crawford (STScI)
NASA Hubble Mission Team Goddard Space Flight Center Nov 14, 2024
A story of survival is unfolding at the outer reaches of our galaxy, and NASA's Hubble Space Telescope is witnessing the saga.
The Large Magellanic Cloud, also called the LMC, is one of the Milky Way galaxy's nearest neighbors. This dwarf galaxy looms large on the southern nighttime sky at 20 times the apparent diameter of the full Moon.
Many researchers theorize that the LMC is not in orbit around our galaxy, but is just passing by. These scientists think that the LMC has just completed its closest approach to the much more massive Milky Way. This passage has blown away most of the spherical halo of gas that surrounds the LMC.
Now, for the first time, astronomers been able to measure the size of the LMC's halo – something they could do only with Hubble. In a new study to be published in The Astrophysical Journal Letters, researchers were surprised to find that it is so extremely small, about 50,000 light-years across. That's around 10 times smaller than halos of other galaxies that are the LMC's mass. Its compactness tells the story of its encounter with the Milky Way.
"The LMC is a survivor," said Andrew Fox of AURA/STScI for the European Space Agency in Baltimore, who was principal investigator on the observations. "Even though it's lost a lot of its gas, it's got enough left to keep forming new stars. So new star-forming regions can still be created. A smaller galaxy wouldn't have lasted – there would be no gas left, just a collection of aging red stars."
This artist's concept shows the Large Magellanic Cloud, or LMC, in the foreground as it passes through the gaseous halo of the much more massive Milky Way galaxy. The encounter has blown away most of the spherical halo of gas that surrounds the LMC, as illustrated by the trailing gas stream reminiscent of a comet's tail. Still, a compact halo remains, and scientists do not expect this residual halo to be lost. The team surveyed the halo by using the background light of 28 quasars, an exceptionally bright type of active galactic nucleus that shines across the universe like a lighthouse beacon. Their light allows scientists to "see" the intervening halo gas indirectly through the absorption of the background light. The lines represent the Hubble Space Telescope's view from its orbit around Earth to the distant quasars through the LMC's gas. NASA, ESA, Ralf Crawford (STScI) Download this image
Though quite a bit worse for wear, the LMC still retains a compact, stubby halo of gas – something that it wouldn't have been able to hold onto gravitationally had it been less massive. The LMC is 10 percent the mass of the Milky Way, making it heftier than most dwarf galaxies.
"Because of the Milky Way's own giant halo, the LMC's gas is getting truncated, or quenched," explained STScI's Sapna Mishra, the lead author on the paper chronicling this discovery. "But even with this catastrophic interaction with the Milky Way, the LMC is able to retain 10 percent of its halo because of its high mass."
A Gigantic Hair Dryer
Most of the LMC's halo was blown away due to a phenomenon called ram-pressure stripping. The dense environment of the Milky Way pushes back against the incoming LMC and creates a wake of gas trailing the dwarf galaxy – like the tail of a comet.
"I like to think of the Milky Way as this giant hairdryer, and it's blowing gas off the LMC as it comes into us," said Fox. "The Milky Way is pushing back so forcefully that the ram pressure has stripped off most of the original mass of the LMC's halo. There's only a little bit left, and it's this small, compact leftover that we're seeing now."
As the ram pressure pushes away much of the LMC's halo, the gas slows down and eventually will rain into the Milky Way. But because the LMC has just gotten past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the whole halo will be lost.
Only with Hubble
To conduct this study, the research team analyzed ultraviolet observations from the Mikulski Archive for Space Telescopes at STScI. Most ultraviolet light is blocked by the Earth's atmosphere, so it cannot be observed with ground-based telescopes. Hubble is the only current space telescope tuned to detect these wavelengths of light, so this study was only possible with Hubble.
The team surveyed the halo by using the background light of 28 bright quasars. The brightest type of active galactic nucleus, quasars are believed to be powered by supermassive black holes. Shining like lighthouse beacons, they allow scientists to "see" the intervening halo gas indirectly through the absorption of the background light. Quasars reside throughout the universe at extreme distances from our galaxy. This artist's concept illustrates the Large Magellanic Cloud's (LMC's) encounter with the Milky Way galaxy's gaseous halo. In the top panel, at the middle of the right side, the LMC begins crashing through our galaxy's much more massive halo. The bright purple bow shock represents the leading edge of the LMC's halo, which is being compressed as the Milky Way's halo pushes back against the incoming LMC. In the middle panel, part of the halo is being stripped and blown back into a streaming tail of gas that eventually will rain into the Milky Way. The bottom panel shows the progression of this interaction, as the LMC's comet-like tail becomes more defined. A compact LMC halo remains. Because the LMC is just past its closest approach to the Milky Way and is moving outward into deep space again, scientists do not expect the residual halo will be lost. NASA, ESA, Ralf Crawford (STScI) Download this image
The scientists used data from Hubble's Cosmic Origins Spectrograph (COS) to detect the presence of the halo's gas by the way it absorbs certain colors of light from background quasars. A spectrograph breaks light into its component wavelengths to reveal clues to the object's state, temperature, speed, quantity, distance, and composition. With COS, they measured the velocity of the gas around the LMC, which allowed them to determine the size of the halo.
Because of its mass and proximity to the Milky Way, the LMC is a unique astrophysics laboratory. Seeing the LMC's interplay with our galaxy helps scientists understand what happened in the early universe, when galaxies were closer together. It also shows just how messy and complicated the process of galaxy interaction is.
Looking to the Future
The team will next study the front side of the LMC's halo, an area that has not yet been explored.
"In this new program, we are going to probe five sightlines in the region where the LMC's halo and the Milky Way's halo are colliding," said co-author Scott Lucchini of the Center for Astrophysics | Harvard & Smithsonian. "This is the location where the halos are compressed, like two balloons pushing against each other."
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Scientists compile library for evaluating exoplanet water
Cornell University
ITHACA, N.Y. – By probing chemical processes observed in the Earth’s hot mantle, Cornell scientists have started developing a library of basalt-based spectral signatures that not only will help reveal the composition of planets outside of our solar system but could demonstrate evidence of water on those exoplanets.
“When the Earth’s mantle melts, it produces basalts,” said Esteban Gazel, professor of engineering. Basalt, a gray-black volcanic rock found throughout the solar system, are key recorders of geologic history, he said.
“When the Martian mantle melted, it also produced basalts. The moon is mostly basaltic,” he said. “We’re testing basaltic materials here on Earth to eventually elucidate the composition of exoplanets through the James Webb Space Telescope data.”
Gazel and Emily First, a former Cornell postdoctoral researcher and now an assistant professor at Macalester College in Minnesota, are authors of “Mid-infrared Spectra for Basaltic Rocky Exoplanets,” which is under embargo until 5am ET on Thursday, November 14 in Nature Astronomy.
Understanding how minerals record the processes that created these rocks, and their spectroscopic signatures is the first step in developing their library, Gazel said.
“We know that the majority of exoplanets will produce basalts, given that their host star metallicity will result in mantle minerals (iron-magnesium silicates) so that when they melt, phase equilibria (equilibrium between two states of matter) predicts that the resulting lavas will be basaltic,” Gazel said. “It will be prevalent not only in our solar system, but throughout the galaxy, too.”
First measured the emissivity – the extent to which a surface radiates the energy it encounters – of 15 basaltic samples for spectral signatures of what the space telescope’s mid-infrared spectrometer may detect.
Once basaltic melts erupt on an exoplanet and cool down, the basalts harden into solid rock, known on Earth as lava. This rock can interact with water, if present, which forms new hydrated minerals easy to spot in the infrared spectra. These altered minerals could become amphibole (a hydrous silicate) or serpentine (another hydrous silicate, which looks like a snake’s skin).
By examining small spectral differences between the basalt samples, scientists can in theory determine whether an exoplanet once had running surface water or water in its interior, said Gazel.
Proof of water does not emerge instantly, and further work is needed before this type of detection can be employed. It would take the James Webb Space Telescope (JWST) – about 1 million miles from Earth – dozens to hundreds of hours to focus on one system light-years away, then more time to analyze the data.
The research group – in looking for a rocky exoplanet to simulate its hypotheses and consider the 15 different signatures – used data from the super Earth exoplanet LHS 3844b, which orbits a red dwarf a little more than 48 light-years away.
Ishan Mishra, working in the laboratory of Nikole Lewis, associate professor of astronomy, wrote computer code modeling First’s spectral data to simulate how differing exoplanet surfaces might appear to the JWST.
Lewis said that modeling tools were first used for other applications. “Ishan’s coding tools were used originally for studying icy moons in the solar system,” she said. “We are now finally trying to translate what we’ve learned of the solar system into exoplanets.”
“The goal was not to assess planet LHS 3844b specifically,” First said, “but rather to consider a plausible range of basaltic rocky exoplanets that could be observed by JWST and other observatories in the coming years.”
In terms of exoplanets, the researchers said exploration of rocky surfaces has been mostly limited to single data points – finding evidence of only type of chemical – in the scientific literature, but that is changing to multiple components as observers make use of the JWST.
By trying to tease out signatures related to mineralogy and bulk chemical composition – for example, how much silicon, aluminum and magnesium are in a rock – the geologists can tell a little more about the conditions under which the rock formed, the geologists said.
“On Earth, if you have basaltic rocks erupting from mid-ocean ridges deep on the ocean floor, versus those erupting at ocean islands like Hawaii,” First said, “you will notice some differences in the bulk chemistry. But even rocks of similar bulk chemistry can contain different minerals, so these are both important characteristics to examine.”
Potential for observing geological diversity from mid-infrared spectra of rocky exoplanets
Article Publication Date
14-Nov-2024
Einstein probe unveils new X-ray transient source EP240408a
Science China Press
image:
The blue curve in the image illustrates the evolution of EP240408a's X-ray flux over time, with purple solid dots marking discrete measurements. A pronounced, brief flare is clearly visible around 0.2 days, signaling a sharp, intense flux increase. The inset at the top right provides a closer view of the flare.
On April 8, 2024, the Einstein Probe's Wide Field X-ray Telescope (WXT) picked up an unusual event designated as EP240408. This previously unseen source emitted X-rays consistently in the 0.5-4 KeV energy range, followed by a brief, intense soft X-ray flare that was 300 times brighter and lasted 12 seconds, featuring three equal-sized peaks, and was quickly followed by a fast decrease in X-ray radiation. Emissions weakened to one-tenth of their original strength by the seventh day and disappeared by day 10. Scientists suggest that the duration of its X-ray activity likely ranges between 7 and 23 days, as it was not observed in WXT data from 13 days earlier.
Astronomers have made use of space telescopes such as EP's FXT, Swift's XRT, and NICER to meticulously scrutinize the X-ray emissions from EP240408a. Despite thorough searches across the electromagnetic spectrum using different telescopes such as GROND, NOT, GSP, MASTER, BOOTES-6, Swift's Ultraviolet/Optical Telescope (UVOT), ATCA, and GECAM-B, no signals beyond the X-ray band were detected. The unique timing and light curves of EP240408a do not correlate with traditional X-ray sources, and the absence of visible light makes it difficult to measure its redshift. Nevertheless, despite these challenges, the scientific team endeavored to compare the changing characteristics and light patterns of EP240408a with other known transient sources, which could be linked to it, in the hope of obtaining useful insights.
Dr. Wenda Zhang, lead author and a researcher at the National Astronomical Observatory, stated, “EP240408a's behavior and spectrum are unlike any known X-ray transients, which is intriguing. It's like nothing we've seen before.”
The X-ray pattern of EP240408a is different from what we usually see. It has a spectrum inconsistent with that from gas with a hot temperature, which sets it apart from regular Tidal Disruption Events (TDEs), which are transient phenomena caused by a supermassive black hole devouring a nearby star. Unlike a specific subclass of TDEs that accelerate gas to nearly the speed of light, EP240408a fades away more quickly and gives off less light in the optical, radio, and near-infrared bands. It also has a bright flare lasting only 12 seconds, similar to the quick flashes we see in long Gamma-Ray Bursts (GRBs) that are chactererized by short but strong bursts and are associated with the deaths of massive stars. However, its steady X-ray light behaves differently from the usual afterglow seen in GRBs. It probably isn't an X-ray Binary (XRB), a system that ocassionally becomes bright from radio to X-rays due to a black hole or neutron star gravitationally attracting matter from its stellar companion, either because its fast fading and weaker light don't match what we expect from XRBs. In terms of X-ray strength and how it changes over time, this object is somewhat like the Fast Blue Optical Transient (FBOT)—a rare type of fast transients originally detected in optical with blue colors, but it is not as bright in the optical range, which makes it unlikely to be an FBOT.
Dr. Weimin Yuan, Principal Investigator of the EP mission, highlighted, “EP240408a's discovery might point to a new type of transient source. These short-term X-ray flares have a time scale of about 10 days and may have been missed in previous time-domain X-ray surveys. This finding demonstrates EP’s power to make new discoveries and helps us understand the variety of extreme physical processes in the universe.”
The Einstein Probe, now referred to as “Tianguan” in Chinese, launched on January 9, 2024, is a team effort by the Chinese Academy of Sciences and international partners including ESA, MPE, and CNES. Only two months after commencing its first light, EP240408a was discovered, and to date, no other sources similar to it have been found in the seven months since.
This finding was reported in "Science China Physics, Mechanics & Astronomy" on October 30th.
The cover image of “Science China Physics, Mechanics & Astronomy” featuring EP240408a.
Above is an image of EP240408 on the X-ray detector captured by the WXT. In the upper right corner, the constellation Taurus is displayed, along with two labeled celestial objects: SN1054 and “Tianguan.” Both objects illustrate EP's commitment to detecting transient sources, as well as the origin of EP's alternate name, "Tianguan."（"Tianguan guest star". "Guest star" is the term used in ancient Chinese to refer to transient events, mostly novae and supernovae bright enough to naked eyes of human at that time. Since as early as the Han dynasty more than 2000 years ago, ancient Chinese had observed and recorded several dozens of the outburst phenomena such as novae and supernovae. The observation and documenting of the supernova SN1054, whose debris has later evolved to become the well-known supernova remnant Crab nebula, is an example of the contribution by ancient Chinese to human's understanding of the universe）
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