Astronomy

You might remember the SLIM lunar lander that managed to land upside-down! The probe from the Japanese Space Agency has survived its second night on the Moon and returns a new photograph. Despite the solar panels pointing away from the Sun during the day it was still able to capture the image and transmit to Earth. All that while surviving the harsh -130C lunar night. 

The Japanese Space Agency (JAXA) sent SLIM (the Smart Lander for Investigating the Moon) back in January but the lightweight spacecraft landed completely wrong. Despite the wonky landing, SLIM touching down in one piece made Japan the fifth nation to land on the surface without crashing. The biggest problem for the mission was the solar panels pointing the wrong way. To the surprise of JAXA though they were able to announce the probe awoke for a second night. 

The lander’s purpose was to research and test the pinpoint landing technology for future lunar missions. The hope is that it will pave the way for future missions to land where we want them to rather than where it is safest and easy to land. This will have benefits for landing on the Moon and on other astronomical bodies. 

The black and white image sent back revealed the rocky surface and a lunar crater. It was released on the SLIM official social media platform with the accompanying text ‘Since the Sun was still high in the sky and the equipment was still hot, we recorded images of the usual scenery with the navigational camera, among other activities for a short period of time.’

The post came shortly after an American unscrewed lander known as Odysseus had failed to wake. The craft became the first American spacecraft to land on the lunar surface since the Apollo 17 mission in 1972. It also became the first privately funded probe to land safely on the Moon’s surface. In a similar landing to SLIM, Odysseus (which came in at just over 4 metres tall) also managed to topple over onto its side following an approach that was too fast. The manufacturers of the Odysseus spacecraft, Intuitive Machines based in Houston, had hoped that it might awake just like SLIM but sadly this does not seem to have occurred. 

A SpaceX Falcon 9 rocket rises from its Florida launch pad to send Intuitive Machines’ Odysseus moon lander spaceward. (NASA via YouTube)

Aside from testing the precision landing technology, SLIM also aims to study part of the Moon’s mantle which it is thought was accessible at the landing site. After its landing, it switched off to save power but the incoming sunlight managed to switch it back on again to enable a couple of days to scientific observations. Given that the probe was not designed to survive the lunar nights, it was a fabulous surprise and bonus for the team.

Source : Japan moon probe survives second lunar night

The post Against all Odds. Japan’s SLIM Lander Survived a Second Lunar Night Upside Down appeared first on Universe Today.

Universe Today has investigated the significance of studying impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, and meteorites, and how these scientific fields contribute to researchers and the public gain greater insight into our place in the universe and finding life beyond Earth. Here, will discuss the field of radio astronomy with Dr. Wael Farah, who is a research scientist at the SETI Institute, about how radio astronomy teaches us about the myriad of celestial objects that populate our universe, along with the benefits and challenges, finding life beyond Earth, and how upcoming students can pursue studying radio astronomy. But what is radio astronomy and why is it so important to study?

“Radio astronomy is a branch of astrophysics dedicated to studying the universe at radio wavelengths, which represent the lowest energy form of the electromagnetic spectrum,” Dr. Farah tells Universe Today. “Originating in the late 1930s, radio astronomy transformed astronomers’ perceptions of the cosmos. Before the serendipitous discovery of radio emissions from the Milky Way, scientists believed that radio emissions from space, attributed to stars and other hot bodies, could only be produced by the “black body” law (or Planck’s law), which accurately predicted that radio emissions should be very weak and undetectable from Earth. However, the discovery of an entirely new emission process, synchrotron radiation, provided an unprecedented lens to view the cosmos through. This opened up a whole new world of discoveries.”

As its name implies, radio astronomy uses radio telescopes to listen to the sounds of the universe, and while radio astronomy is often interpreted as just listening for aliens (which is one branch), most of radio astronomy consists of listening to radio waves from other celestial sources, some of which are millions of light-years from Earth, including gas giant planets, gas clouds, pulsars, the birth and death of stars, galaxy formation and evolution, and the Cosmic Microwave Background Radiation.

The size of radio telescopes range between small, homemade antennas to massive dishes that collect radio waves from space and use computers to boost (also known as “amplify”) the radio signals, followed by using computer programs to translate the signal into easy-to-understand data. Astronomers then use this data to conduct studies on the aforementioned celestial objects, thus increasing our understanding of the universe. But even with all the science being accomplished and the required technology, what are some of the benefits and challenges of study radio astronomy?

“Radio astronomy is an inherently interdisciplinary field, intersecting science, engineering, and computing, which presents both benefits and challenges,” Dr. Farah tells Universe Today. “Speaking of challenges, there’s no shortage of them! Radio Frequency Interference (RFI) poses a significant challenge for radio astronomers. Almost every communication device, from radios and cell phones to satellites and WiFi routers, operates within the radio portion of the electromagnetic spectrum. These devices interfere with radio telescopes and can cause substantial damage to equipment and data. We’re constantly endeavoring to modify our hardware and software to adapt to, or even mitigate, this increasingly detrimental environment.”

Radio astronomy is often described as “observing the invisible universe”, and one example is studying magnetic fields around planets, stars, and even galaxies. This is accomplished through measuring what’s known as synchrotron radiation, which are radio waves created by magnetic fields, and have been identified around black holes, allowing researchers to learn more about the black hole’s behavior and characteristics, including how they digest stars. Within our own solar system, radio astronomy can be used to study the magnetic fields comets, the gas giants, Jupiter and Saturn, and even our Sun. This is because radio telescopes “see” the universe differently than optical telescopes, or visible light. Other examples include quasars, which look like normal stars but can emit powerful radio bursts that radio astronomers collect to learn more about them, including their formation and evolution. But with all these fascinating celestial objects to study, what are some of the most exciting aspects of radio astronomy that Dr. Farah has studied during his career?

Artist’s illustration of a red dwarf star’s magnetic field. (Credit: Dana Berry; (NRAO/AUI/NSF))

“One of my research interests is the study of Fast Radio Bursts (or FRBs in short),” Dr. Farah tells Universe Today. “FRBs are brief but incredibly intense bursts of radio waves, seemingly originating from sources halfway across the universe. Despite their enigmatic nature, our leading theories suggest that FRBs may be linked to highly magnetized neutron stars known as magnetars. FRBs hold the imprint of the medium they travel through, offering a unique window into the universe. I am also interested in the Search for Extraterrestrial Intelligence (or SETI). Radio astronomy is a promising avenue for discovering life beyond our planet, seeking to address one of humanity’s most profound and enduring questions: ‘are we alone in the universe?’.”

Dr. Farah has frequently spoken about the Allen Telescope Array (ATA) in northern California, whose mission is to continue SETI research and provides researchers the opportunity to search the heavens for radio signals from other intelligent civilizations seven days a week. The ATA was heavily-funded by the Paul G. Allen Family Foundation, for which the array is named after, and began operations in 2007.

One of the most famous radio telescopes in the world was the Arecibo Observatory in Puerto Rico, which boasted a massive dish that measured 305-meters (1000-feet) in diameter, and contributed to radio astronomy, radar astronomy, and the Search for extraterrestrial intelligence (SETI) during its service between 1963 and 2020. Unfortunately, Arecibo encountered funding lapses in the early 2000s as NASA put an emphasis on newer radio telescopes, and the disk sustained damage during Hurricane Maria in 2017. In December 2020, support cables that hoisted the instrument platform snapped, causing the platform to crash into the dish. After that, the National Science Foundation (NSF) announced plans to not rebuild the site, but instead have an educational facility put at the location.

The Arecibo Observatory was featured in the film Contact, which Jodie Foster was using to listen for signals from extraterrestrials. While only featured in the beginning of the film, it nonetheless underscored the importance of Arecibo’s role in conducting vital scientific research to help us better understand our place in the universe. The radio observatory that served as the location for Jodie Foster identifying the radio signal from Vega occurred at the Karl G. Jansky Very Large Array (VLA) in Socorro, New Mexico, which is currently operated by the National Radio Astronomy Observatory (NRAO) with funding from the NSF and is actively being used for SETI research. Therefore, what can radio astronomy teach us about finding life beyond Earth?

Image of radio telescopes at the Karl G. Jansky Very Large Array, located in Socorro, New Mexico. (Credit: National Radio Astronomy Observatory)

“Technosignatures, which are indicators of non-anthropogenic technology, serve as one proxy for detecting intelligent extraterrestrial civilizations,” Dr. Farah tells Universe Today. “As an emerging civilization ourselves, humans have utilized radio waves for various purposes like communication services, radar, and sensing. Therefore, it is reasonable to assume that an extraterrestrial civilization would also develop and utilize radio technology, and perhaps even broadcast their existence across the galaxy. Unlike other forms of light that could carry the evidence of life beyond our solar system, radio waves can propagate unobscured by interstellar gas and dust, making them easily detectable across vast distances.”

There are currently more than 100 operational radio telescopes around the world and on all seven continents, with a few space-based radio telescopes, as well. These include the aforementioned VLA but also includes the Five-hundred-meter Aperture Spherical Telescope (FAST) in China, which surpassed Arecibo as the world’s largest filled-aperture radio telescope, which conducts studies on pulsars, interstellar molecules, and SETI research. Given the myriad of science and celestial objects that radio astronomy studies, success requires constant collaboration from scientists across the globe and equally from a myriad of backgrounds, including astronomy, physics, astrophysics, chemistry, computer science, electrical engineering, geology, and geophysics. Therefore, what advice does Dr. Farah offer upcoming students who wish to pursue studying radio astronomy?

“Radio astronomy is deeply rooted in physics, mathematics, and computer science,” Dr. Farah tells Universe Today. “Having a solid understanding of these subjects, as they form the basis of many concepts in radio astronomy, can be extremely helpful when studying the field. I would also encourage upcoming students to try and gain research experience by seeking out opportunities to participate in research projects, internships, or summer projects. Radio observatories often offer positions like telescope operators that can be equally fulfilling and rewarding. Reaching out to potential mentors for projects that one might find intriguing is also very crucial; sometimes a short but concise email that shows passion and interest can go a long way! Radio astronomy is a fascinating field, you can never go wrong!”

As technology continues to help advance our knowledge of the universe, radio astronomy will be at the forefront of gaining that knowledge, and possibly even be responsible for receiving a radio signal from an extraterrestrial civilization from somewhere in the cosmos. This incredible field has allowed thousands of scientists from all over the world to gain new insights about black holes, galaxies, quasars, and even about our Sun and the planets with our solar system. Given the more than 100 active radio telescopes across all seven continents, the future is bright for radio astronomy and the cutting-edge science it can achieve.

“Despite being a relatively young field, radio astronomy has already made significant contributions to astronomy and science, greatly advancing our understanding of the universe,” Dr. Farah tells Universe Today. “This impact has been recognized at the highest levels. The Nobel Prize in Physics was awarded in 1974 for pioneering techniques in radio astrophysics and the discovery of pulsars. In 1978, the Nobel Prize in Physics was awarded for the discovery of the Cosmic Microwave Background and evidence supporting the Big Bang theory. Additionally, in 1993, another Nobel Prize in Physics was awarded for the discovery of binary pulsar systems, which enabled novel methods for studying gravitation. As major discoveries continue to unfold, I anticipate the possibility of another few Nobel Prizes in the coming years. This underscores the scientific richness of the field.”

How will radio astronomy help us better understand our place in the universe in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Radio Astronomy: Why study it? What can it teach us about finding life beyond Earth? appeared first on Universe Today.

Studying exoplanets is made more difficult by the light from the host star. Coronagraphs are devices that block out the star light and both JWST and Nancy Grace Roman Telescope are equipped with them. Current coronagraphs are not quite capable of seeing other Earths but work is underway to push the limits of technology and even science for a new, more advanced device. A new paper explores the quantum techniques that may one day allow us to make such observations. 

Coronagraphs are devices that attach to telescopes and were originally designed to study the corona of the Sun. The corona is the outermost layer of the Sun’s atmosphere but is usually hidden from view from the bright light emitted from the photosphere (the visible layer). The device has also been modified to hide the light from stars to study faint objects in their vicinity. These stellar coronagraphs are often employed to hunt for extrasolar planets and the disks out of which they form. 

The 5,000th comet discovered with the Solar and Heliospheric Observatory (SOHO) spacecraft is noted by a small white box in the upper left portion of this image. A zoomed-in inset shows the comet as a faint dot between the white vertical lines. The image was taken on March 25, 2024, by SOHO’s Large Angle and Spectrometric Coronagraph (LASCO), which uses a disk to block the bright Sun and reveal faint features around it. Credit: NASA/ESA/SOHO

There are a number of techniques to identify extrasolar planets but direct imaging is one of the chief ways to learn about their nature. The challenge, which is met by the stellar coronagraph, is the brightness of the star and the relative faintness of the planet and proximity to the star. Coronagraphs can increase the ratio between noise (in this instance the light from the star) and the signal from the exoplanet by optically removing the light from the star. In a paper from authors Nico Deshler, Sebastian Haffert and Amit Ashok from the University of Arizona they explore whether coronagraphs are the best method for hunting exoplanets. 

Studying exoplanets is important to help us to learn about planetary formation, atmospheric sciences and even perhaps, the origins of life. The team approached their analysis of coronagraphic techniques by considering first the detection step and then the localisation task in exoplanets research. They first undertook a hypothesis test to see if it was likely an exoplanet existed. If the prediction played out and an exoplanet was found to exist then the team attempted to estimate its position. Turning to quantum limits for telescopic resolution, they used quantum mechanics to produced a limit of the position of the exoplanet. 

The team then compared classical direct imaging coronagraphs to the quantum predictions above. It should be noted that this research was focussing on the capability of  present coronagraphs to detect Earth-like exoplanets using quantum theory. The research concludes that the complete rejection of a telescopes optical mode is key to achieving the best possible detection techniques. Host star and planet separations that are so close as to be below the diffraction limit of the telescopes are thought to be abundant across the universe. It is therefore necessary that quantum-optimal coronagraphs are developed and it is encouraging that this research finds they will yield some impressive results. 

Source : Achieving Quantum Limits of Exoplanet Detection and Localization

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What does a supernova remnant sound like?

Countries from Sierra Leone to Mexico are looking for low-cost, easy ways to protect residents from extreme heat, such as planting shade trees and setting up warning systems

Can binary black holes, two black holes orbiting each other, influence their respective behaviors? This is what a recent study published in Science Advances hopes to address as a team of more than two dozen international researchers led by the Massachusetts Institute of Technology (MIT) investigated how a smaller black hole orbiting a supermassive black hole could alter the outbursts of the energy being emitted by the latter, essentially giving it “hiccups”. This study holds the potential to help astronomers better understand the behavior of binary black holes while producing new methods in finding more binary black holes throughout the cosmos.

“We thought we knew a lot about black holes, but this is telling us there are a lot more things they can do,” said Dr. Dheeraj “DJ” Pasham, who is a research scientist in MIT’s Kavli Institute for Astrophysics and Space Research and lead author of the study. “We think there will be many more systems like this, and we just need to take more data to find them.”

For the study, the researchers used a half dozen scientific instruments to obtain radio, ultraviolet, optical, and x-ray data on ASASSN-20qc, which is located approximately 260 megaparsecs (848,000,000 light-years) from Earth and was previously identified as a tidal disruption event (TDE) when first discovered in December 2020. The TDE responsible for astronomers first discovering ASASSN-20qc was caused by a star coming too close to the supermassive black hole and being slowly consumed over a four-month period. However, Dr. Pasham later looked over the data and found dips in energy output from the supermassive black hole occurring every 8.5 days throughout this four-month period.

Combining this data with computer models, the researchers confirmed the 8.5-day bursts of energy being emitted by supermassive black hole, which they hypothesize is caused by the smaller black orbiting around the larger one, with its own gravity influencing the gas and energy within the supermassive black hole’s disk. The researchers compare this phenomenon to an exoplanet transiting its parent star, resulting in a brief dip in starlight. These findings indicate that the disks of gas around black holes are far more chaotic than longstanding hypotheses have claimed.

“This is a different beast,” said Dr. Pasham. “It doesn’t fit anything that we know about these systems. We’re seeing evidence of objects going in and through the disk, at different angles, which challenges the traditional picture of a simple gaseous disk around black holes. We think there is a huge population of these systems out there.”

The supermassive black hole examined in this study exists at the center of its respective galaxy similar to other supermassive black holes found through the cosmos, with Sagittarius A* being the supermassive black hole at the center of our Milky Way Galaxy. However, finding another black hole orbiting the one examined in this study could help astronomers better understand the formation and evolution of supermassive black holes throughout the universe, with the study noting this research could lead to new methods in identifying binary black hole candidates, as well.

The reason astronomers are interested in learning more about binary black holes is the potential for them to teach us about gravitational waves, which were first proposed in the late 19th and early 20th century and gained traction in their existence and relevance through Albert Einstein’s general theory of relativity, as these gravitational waves have been hypothesized to create ripple in the fabric of spacetime. These gravitational waves are produced from the merging of binary black holes, with astronomers first detecting a black hole merger by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and corresponding results published in Physical Review Letters in 2016.

What new discoveries will astronomers make about binary black holes in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post A Supermassive Black Hole with a Case of the Hiccups appeared first on Universe Today.

Universe Today has explored the importance of studying impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, and cosmochemistry, and how this myriad of intricately linked scientific disciplines can assist us in better understanding our place in the cosmos and searching for life beyond Earth. Here, we will discuss the incredible research field of meteorites and how they help researchers better understand the history of both our solar system and the cosmos, including the benefits and challenges, finding life beyond Earth, and potential routes for upcoming students who wish to pursue studying meteorites. So, why is it so important to study meteorites?

Dr. Alex Ruzicka, who is a Professor in the Department of Geology at Portland State University, tells Universe Today, “They provide our best information about how the solar system formed and evolved. This includes planet formation. We also obtain information on astrophysics (stellar processes) through studies of pre-solar grains.”

There is often confusion regarding the differences between an asteroid, meteor, and meteorite, so it’s important to explain their respective differences to help better understand why scientists study meteorites and how they study them. An asteroid is a physical, orbiting planetary body that is primarily comprised of rock, but can sometimes be comprised of additional water ice, with most asteroids orbiting in the Main Asteroid Belt between Mars and Jupiter and the remaining orbiting as Trojan Asteroids in the orbit of Jupiter or in the Kuiper Belt with Pluto. A meteor is the visual phenomena that an asteroid produces as it burns up in a planet’s atmosphere, often seen as varying colors from the minerals within the asteroid when heated up. The pieces of the asteroid that survive the fiery entry and hit the ground are called meteorites, which scientists’ study to try and learn about the larger asteroid body it came from, and where that asteroid could have come from, as well. But what are some of the benefits and challenges of studying meteorites?

Dr. Ruzicka tells Universe Today, “Benefits: scientific knowledge, information on potential resources (e.g., metals, water) for humans to utilize, information on how to link meteorites and asteroids, which can provide information on space collision hazards for Earth. Challenges: compared to Earth rocks, we lack field evidence for their source bodies and parent bodies (how they relate to other rocks), we have to factor in the element of time that is longer for space rocks than for Earth rocks, and sometimes we are dealing with formation environments completely unlikely what we have on Earth. So, the challenges are big and many.”

According to NASA, more than 50,000 meteorites have been retrieved from all over the world, ranging from the deserts of Africa to the snowy plains of Antarctica. In terms of their origins, it is estimated that 99.8 percent of these meteorites have come from asteroids, with 0.1 percent coming from the Moon and 0.1 percent coming from Mars. The reason why we’ve found meteorites from the Moon and Mars is due to pieces of these planetary bodies being catapulted off their surfaces (or sub-surfaces) after experiencing large impacts of their own, and these pieces then travel through the Solar System for thousands, if not millions, of years before being caught in Earth’s gravity and the rest is history. Therefore, with meteorites originating from multiple locations throughout the Solar System, what can meteorites teach us about finding life beyond Earth?

Morgan Nunn Martinez, who was a PhD student at UC San Diego, and Dr. Alex Meshik seen photographing and measuring a meteorite specimen in Antarctica’s Miller Range during the 2013-2014 Antarctic Search for Meteorites (ANSMET) program field season. (Credit: NASA/JSC/ANSMET)

“That the ingredients for making life formed in space and were delivered to Earth,” Dr. Ruzicka tells Universe Today. “We know organic molecules formed in gas clouds, were incorporated in our solar system, and processed in asteroidal and cometary bodies under higher temperatures in the presence of water. These were then delivered to Earth which wouldn’t have been very hospitable in early times due to sterilizing impacts. We also know that there must have been a lot of planetary rock swapping early when impact rates were high. Life itself may have been transplanted to Earth from Mars.”

As it turns out, one of the most fascinating meteorites ever recovered did come from Mars, which was identified as ALH84001, as it was found in Allan Hills of Antarctica on December 27, 1984, during the 1984-85 field season where researchers from all over the world gather in Antarctica to search for meteorites using snowmobiles. Despite being collected in 1984, it wasn’t until 1996 that a team of scientists discovered what initially appeared to be evidence of microscopic bacteria fossils within the 1.93-kilogram (4.25-pound) meteorite.

ALH84001, which is one of the most famous meteorites ever recovered, helped catapult the field of astrobiology to new heights when scientists uncovered what initially appeared to be microscopic bacteria fossils within this meteorite, though those findings remain inconclusive to this day. (Credit: NASA)

This immediately made headlines across the globe, resulting in countless non-scientific claims that these microfossils were clear evidence of life on Mars. However, both the researchers of the initial study and the scientific community were quick to point out the unlikelihood that these features resulted from life based on other observations made about ALH84001. For example, while ALH84001 is estimated to be 4.5 billion years old, which is when Mars is hypothesized to have possessed liquid water on its surface, radiometric dating techniques revealed that ALH84001 was catapulted off Mars approximately 17 million years ago and landed on Earth approximately 13,000 years ago.

Microscopic image of ALH84001, which initially made headlines for potentially possessing microscopic bacteria fossils, though these finding remain inconclusive to this day. (Credit: NASA)

To this day, there has been no clear evidence that ALH84001 ever contained traces of life. Despite this, ALH84001 has nonetheless helped launch the field of astrobiology into new heights, with present-day scientists claiming this one meteorite was the reason they pursued their career path to find life beyond Earth. But what have been the most exciting aspects about meteorites that Dr. Ruzicka has studied throughout his career?

Dr. Ruzicka tells Universe Today, “A lot is interesting, what’s most exciting? That’s hard to say. I get satisfaction from taking clues left by the rocks to figure out or constrain the processes that formed them. I am engaged in a meteoritic version of CSI, we can call it MSI (for meteoritic scene investigation).”

Like many scientific fields, this “meteoritic version of CSI” requires individuals from a myriad of backgrounds and disciplines, including geology, physics, geochemistry, cosmochemistry, mineralogy, and artificial intelligence, just to name a few, with the aforementioned radiometric dating frequently used to estimate the ages of meteorites by measuring the radioactive isotopes within the sample. It is through this constant collaboration and innovation that scientists continue to unlock the secrets of meteorites with the goal of understanding their origins and compositions, along with how our Solar System, and life on Earth (and possibly elsewhere), came to be. Therefore, what advice can Dr. Ruzicka offer upcoming students who wish to pursue studying meteorites?

Dr. Ruzicka tells Universe Today, “Work hard and pursue your dreams. Find a rigorous program of study because it will come in handy.”

While meteorites are space rocks that crash land on Earth after traveling through the heavens for millions, and possibly billions, of years, these incredible geologic specimens are slowly helping scientists’ piece together the origins of the Solar System and beyond, and even how life might have come to be on our small, blue world, and possibly elsewhere. With a myriad of tools and instruments at their disposal, scientists from all over the world will continue to study meteorites in hopes of answering the universe’s toughest questions.

Dr. Ruzicka concludes by telling Universe Today, “Rocks from space are the best kinds of rocks to study. Way more cool than most rocks on Earth because they are in some ways more puzzling.”

How will meteorites help us better understand our place in the cosmos in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Meteorites: Why study them? What can they teach us about finding life beyond Earth? appeared first on Universe Today.

On March 20th, China’s Queqiao-2 (“Magpie Bridge-2”) satellite launched from the Wenchang Space Launch Site LC-2 on the island of Hainan (in southern China) atop a Long March-8 Y3 carrier rocket. This mission is the second in a series of communications relay and radio astronomy satellites designed to support the fourth phase of the Chinese Lunar Exploration Program (Chang’e). On March 24th, after 119 hours in transit, the satellite reached the Moon and began a perilune braking maneuver at a distance of 440 km (~270 mi) from the lunar surface.

The maneuver lasted 19 minutes, after which the satellite entered lunar orbit, where it will soon relay communications from missions on the far side of the Moon around the South Pole region. This includes the Chang’e-4 lander and rover and will extend to the Chang’e-6 sample-return mission, which is scheduled to launch in May. It will also assist Chang’e-7 and -8 (scheduled for 2026 and 2028, respectively), consisting of an orbiter, rover, and lander mission, and a platform that will test technologies necessary for the construction of the International Lunar Research Station (ILRS).

A perilune braking maneuver is vital to establishing a lunar orbit and consists of a thruster firing as the spacecraft approaches the Moon. This reduces the spacecraft’s relative velocity to less than the lunar escape velocity (2.38 km/s; 1.74 mps) so that it can be captured by the Moon’s gravity. Two experimental satellites that will test navigation and communication technology (Tiandu-1 and -2), which accompanied the Queqiao-2 satellite to the Moon, also performed a perilune braking maneuver and entered lunar orbit on Monday.

These two satellites will remain in formation in an elliptical lunar orbit and will conduct communication and navigation tests, including laser ranging with the Moon and microwave ranging between satellites. According to the CNSA, Queqiao-2 will enter a 24-hour elliptical orbit around the Moon at a distance of 200 km (125 mi) at its closest point (perigee) and 100,000 km (62,000 mi) at its farthest point (apogee). Mission controllers will further alter Queqiao-2’s orbit and inclination to bring it into a “200 by 16,000-km, highly-elliptical ‘frozen’ orbit.”

Within this highly stable orbit, Queqiao-2 will have a direct line of sight with ground stations on Earth and the far side of the Moon and will conduct communication tests with Chang’e-4 and Chang’e-6 using its 4.2-m (13.8-ft) parabolic antenna. The mission could also support other countries in their lunar exploration efforts, many of whom are also interested in scouting the Moon’s far side and southern polar region. The satellite also carries scientific instruments, including extreme ultraviolet cameras, array-neutral atom imagers, and lunar orbit Very Long Baseline Interferometry (VLBI) test subsystems.

According to state-owned media company CCTV, the CNSA chose the Queqiao-2 satellite’s present orbit for a multitude of reasons:

“Experts told me that this is an ideal location on the Moon to observe the separation of the Queqiao-2 star arrow, and it also has a deep connection with China’s lunar exploration project. This is the Moon’s rich maria region… Fifteen years ago, on March 1, 2009, it was here that the Chang’e-1 probe of China’s lunar exploration project completed a controlled collision with the Moon… The location of the Sea of Abundance on the moon is also very eye-catching. The next time the moon is full, you look up at the moon and find this dark black patch in the southeast of the moon. This is the Sea of Abundance!”

Visualization of the ILRS from the CNSA Guide to Partnership (June 2021). Credit: CNSA

The satellite will support China’s upcoming Chang’e-6 mission, China’s second attempt to return lunar samples to Earth. Mission controllers will adjust its orbit into a 12-hour period to support the Chang’e-7 and -8 missions. These missions aim to map the terrain and scout resources (particularly water ice) around the South Pole-Aitken Basin. These missions will ultimately support the creation of the ILRS, a joint project between CNSA and Roscomos to create a lunar base that will enable research and development on the Moon.

This program is intended to rival NASA’s Artemis Program, which will send astronauts on a circumlunar flight next year – the Artemis II mission. The program will culminate in 2026 with the first crewed mission to the lunar surface (Artemis III) in over 50 years. NASA also plans to deploy the core elements of the Lunar Gateway next year, an orbital habitat that will facilitate the deployment of the Artemis Base Camp. Along with its international and commercial partners, these elements will support the creation of “a sustained program of lunar exploration and development.”

Further Reading: CGTN

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Some stars are so massive and so energetic that they’re a million times brighter than the Sun. This type of star dominated the early Universe, playing a key role in its development and evolution. The first of its kind are all gone now, but the modern Universe still forms stars of this type.

These hot, blue stars emit powerful ultraviolet energy that the Hubble can detect from its perch in Low-Earth Orbit.

In December 2023, astronomers completed a three-year survey of these hot stars. It’s one of the Hubble’s largest and most ambitious surveys. It’s called ULLYSES (Ultraviolet Legacy Library of Young Stars as Essential Standards), and in it, astronomers gathered detailed information on almost 500 stars.

UV emissions from hot young stars provide a window into some of the processes inside these stars. UV can’t be observed from Earth because the ozone layer blocks it. That’s one of the reasons the Hubble was built. From its perch, it can gather high-resolution UV images. That’s the impetus for ULLYSES.

The survey doesn’t contain images of all the stars. Instead, the Hubble gathered spectra from 220 stars and combined them with Hubble archival data on 275 additional stars. Powerful ground-based telescopes also made a contribution, though not in UV. The result is a very rich dataset consisting of detailed spectra from both hot, bright, massive stars and from cool, dim, low-mass stars.

“I believe the ULLYSES project will be transformative, impacting overall astrophysics – from exoplanets to the effects of massive stars on galaxy evolution, to understanding the earliest stages of the evolving universe,” said Julia Roman-Duval, Implementation Team Lead for ULLYSES at the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “Aside from the specific goals of the program, the stellar data can also be used in fields of astrophysics in ways we can’t yet imagine.”

The ULYSSES spectra collected by Hubble can reveal the presence of chemical elements in the stars. Image Credit: Hubble/ STScI/ULYSSES

Spectra can tell astronomers more than just the metallicity of the stars. They can also reveal the powerful stellar winds coming from the hot blue stars.

Massive blue stars have powerful winds that shape their surroundings. The Hubble spectra can tell which way the winds travel and how fast they travel. The star represented by the teal line has slower winds than the star shown by the purple line. Image Credit: Hubble/ STScI/ULYSSES

Spectra also reveal the metallicity of stars. Stars with lower metallicity are typically older than stars with higher metallicity. A critical part of stellar metallicity concerns the iron content. Astronomers use iron content and its ratio with hydrogen to date stars in relation to our own Sun’s iron and hydrogen ratio.

These spectra show the iron content for two stars. In this image, the star represented by the purple line has less iron, indicating that it’s older than the other star. Iron content affects a star’s lifetime and the strength of its winds. Image Credit: Hubble/ STScI/ULYSSES

In ULYSSES, Hubble targeted hot blue stars in nearby galaxies with low metallicity, the type that would’ve existed in the early Universe. At that point in the Universe’s life, they would’ve contained nothing heavier than hydrogen and helium. This type of galaxy was common in the very early universe. Only once these hot young stars died and spread the elements they created inside themselves would the heavier elements needed for rocky planets, water, and even life be available. “ULLYSES observations are a stepping stone to understanding those first stars and their winds in the Universe and how they impact the evolution of their young host galaxy,” said Roman-Duval.

ULLYSES also observed stellar counterparts to the massive, hot stars: cool, red, low-mass, and dim stars. While the more massive stars form quickly, burn bright, and die soon, these ones are the opposite. They take longer to form, are dimmer, and last much longer. But they still emit winds and energy that shape their surroundings. They’re called T-Tauri stars, stars so young they’re still growing.

As part of the three-year ULYSSES survey, the Hubble also observed cool, dim, low-mass stars like the one in this artist’s illustration, which are still growing by accreting material from their disks. Image Credit: Robert O’Connell (UVA), SOC-WFC3, ESO

Despite their lower masses, these stars emit powerful radiation. During their formation, they’re known to unleash powerful blasts of both UV and X-ray radiation.

There are outstanding questions about T-Tauri stars and how they behave. Some of their processes are obscured. But the Hubble spectra from ULYSSES can provide some answers. They can reveal how much energy T-Tauri stars release as they grow and how powerful their winds are. Their powerful winds can alter their protoplanetary disks, blowing material away and making it unavailable for planet formation. In some cases, the powerful energy from these stars could eliminate the habitability of any planets forming around them.

The ULYSSES data is not meant to answer any specific question. Rather, it’s a massive database of detailed spectra that researchers can query to serve future research. The overarching goal is to provide an in-depth database of spectra from young stars that are in the first 10 million years of their lives.

“More fully understanding the formation and lives of young stars has connections to many other areas in astronomy, including galaxy formation and evolution, the mechanics and mass loss of supernovas, how stars’ environments impact planet formation, and how their emissions may play a role in the makeup of the interstellar medium, the gas and dust between stars in a galaxy,” the ULYSSES website explains. 

ULYSSES is an observing program designed by the research community for the research community. By extension, it also serves those of us who like to follow along as researchers discover new things about the Universe.

“ULLYSES was originally conceived as an observing program utilizing Hubble’s sensitive spectrographs. However, the program was tremendously enhanced by community-led coordinated and ancillary observations with other ground- and space-based observatories,” said Roman-Duval. “Such broad coverage allows astronomers to investigate the lives of stars in unprecedented detail and paint a more comprehensive picture of the properties of these stars and how they impact their environment.”

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