Sunday, March 31, 2024

It Takes a Supercomputer to Properly Simulate a Neutron Star’s Surface

Neutron stars, the remains of massive stars that have imploded and gone supernova at the end of their life, can still create massive flares. These incredible bursts of energy release X-rays that propagate through space. It is a complex process to simulate but astronomers have turned to a supercomputer to help. Modelling the twisting magnetic fields, the interaction with gas and dust, the surface of flaring neutron stars has been revealed in incredible 3D.

Throughout a stars life, the inward force of gravity is balanced by the outward pushing thermonuclear force. Stars like our Sun will experience the thermonuclear force overcoming the force of gravity. The force of gravity wins over the thermonuclear force in more massive stars as the star’s core collapses, leading to a rebound and supernova explosion. The result is a super dense core where the space between the protons and neutrons are eradicated during collapse. The result, is a great big neutron a few kilometres across.

A composite image of the remnant of supernova 1181. A spherical bright nebula sits in the middle surrounded by a field of white dotted stars. Within the nebula several rays point out like fireworks from a central star. G. Ferrand and J. English (U. of Manitoba), NASA/Chandra/WISE, ESA/XMM, MDM/R.Fessen (Dartmouth College), Pan-STARRS

It is quite possible for neutrons stars to have a companion star and, as the stars orbit, the neutron star strips material off its companion. The material will build up on the neutron star, become compressed under the force of gravity which leads to a thermonuclear explosion and a release of X-rays. Understanding this X-ray release and how it spreads across the neutron star’s surface can tell us a lot about the neutron star and its composition. 

A team of astrophysicists from the State University of New York and the University of California have been attempting to simulate the X-ray bursts in 2D and 3D models. One of the challenges in achieving this is the immense amount of computing power required to achieve the task. To overcome this, the team used the Oak Ridge Leadership Computing Facility’s Summit super computer to analyse and compare models. 

The Summit supercomputer is well suited to the task. Combining high-performance CPU and an accelerated graphics processing unit the team were able to run the simulations. By delegating the task of running the simulations to the graphics processing unit the central processing unit was freed up to compare the models. The researchers were able to restrict the size of the source so that they could calculate the neutron star radius. Typically a neutron star has a mass of up to 2 times the mass of the Sun even though they are usually up to 12km across. Studying the flares means the mass and radius of a neutron star can be deduced due to the way matter behaves under extreme conditions. 

The generated models in 3D were informed from previous 2D models. Using models under different star surface temperature and rotation rate, the flames propagation was explored. the 2D study showed that different physical conditions led to a different rate of flame spread. The 3D simulations looked at the evolution of a flare across the surface of a neutron star with a surface temperature several million times more than the Sun and a rotation rate of 1,000 hertz or 1,000 revolution per second. In these simulations the flame does not remain circular and the resultant ash was used to learn how quickly the burning progressed. 

The results revealed that the 2D model burning was slightly faster than the 3D model but both were similar. If more complex interactions are required such as turbulence then the 3D model will be required. Exciting times are ahead for the time as they continue to strive to be able to model the whole flame spread across the entire star. 

Source : Scientists use Summit supercomputer to explore exotic stellar phenomena

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The Search for the Perfect Coronagraph to Find Earth 2.0

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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Saturday, March 30, 2024

A Supermassive Black Hole with a Case of the Hiccups

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!

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Meteorites: Why study them? What can they teach us about finding life beyond Earth?

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!

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China's Relay Satellite is in Lunar Orbit

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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The Hubble Aims Its Powerful Ultraviolet Eye at Super-Hot Stars

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
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
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
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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Friday, March 29, 2024

Search for Life on Mars Could Level-Up with MARSE Mission Concept

A recent study presented at the 55th Lunar and Planetary Science Conference (LPSC) discusses the Mars Astrobiology, Resource, and Science Explorers (MARSE) mission concept and its Simplified High Impact Energy Landing Device (SHIELD), which offers a broader and cheaper method regarding the search for—past or present—life on the Red Planet, specifically by using four rovers at four different landing sites across Mars’ surface instead of just one-for-one. This concept comes as NASA’s Curiosity and Perseverance rovers continue to tirelessly explore the surface of Mars at Gale Crater and Jezero Crater, respectively.

Here, Universe Today discusses the MARSE mission concept with the study’s sole author, Alex Longo, who is a MS student in the Department of Earth, Marine and Environmental Sciences at the University of North Carolina at Chapel Hill, regarding the motivation behind MARSE, how the landing sites were chosen, significant implications, current work being conducted, and next steps for MARSE becoming an actual mission. Longo draws on his ten-plus years of experience finding landing sites on Mars, along with having several publications under his belt, including an assortment of scientific abstracts, papers, and a Kindle book. So, what was the motivation behind the MARSE mission concept?

“The overarching goal of the MARSE concept study was to reduce the cost of access to the surface of Mars,” Longo tells Universe Today. “Flagship-class rovers, such as Curiosity and Perseverance, are extremely capable vehicles. The caveat is that, since they cost over a billion dollars apiece, we can only visit one or two sites on Mars every decade. Like Earth, Mars is an astoundingly diverse planet. Using satellites in orbit, we have mapped a variety of ancient environments which may have been habitable in the distant past. However, the resolution of orbital imagery and spectra are limited, and they sometimes fail to predict what a field geologist (or, in the case of Mars, a rover controlled by geologists) will discover on the ground. Even on Earth, finding early biosignatures is difficult, and even with comparatively little weathering and erosion, I would not be surprised if the same is true on Mars. MARSE was intended to present one possible solution which would allow planetary scientists to explore more sites on Mars within a realistic budget.”

The car-sized Curiosity rover landed in Gale Crater on August 6, 2012, with its mission website displaying that Curiosity has traveled a total of 31.27 kilometers (19.43 miles) as of January 27, 2024, having far surpassed its primary mission timeline of one Martian year, or 687 Earth days. Gale Crater was chosen as the landing site due to a multitude of evidence that it once held liquid water at some point in Mars’ ancient past, as scientists estimate that Gale Crater was formed from an impact between approximately 3.5 to 3.8 billion years ago. During its time in Gale Crater, Curiosity has used its suite of scientific instruments to identify evidence of past liquid water within Gale Crater and evidence that Mars once contained the building blocks for life, including carbon, oxygen, nitrogen, phosphorus, and sulfur.

A selfie of NASA’s Curiosity rover taken on Oct. 11, 2019, or the 2,553rd Martian day, or sol, of its long and successful mission. (Credit: NASA/JPL-Caltech/Malin Space Science Systems)

The car-sized Perseverance rover landed in Jezero Crater on February 18, 2021, with its mission website displaying that Perseverance has traveled a total of 25.113 kilometers (15.604 miles) as of March 28, 2024. While Perseverance and Curiosity have similar designs, the main upgrade has been the delivery of the Ingenuity helicopter to Mars, which became the first robotic explorer to achieve a powered flight on another world and accomplished dozens of flights before being permanently grounded after damaging one of its rotor blades on what would be its final landing in January 2024. Like Gale Crater for Curiosity, Jezero Crater was chosen as the landing site for Perseverance due to strong evidence that it once held a massive body of liquid water, which is made evident from the enormous fan-delta deposit that was the likely entry point for the liquid water billions of years ago. During its time in Jezero Crater, Perseverance has used its suite of scientific instruments to identify ancient volcanic rocks, sediments from an ancient lakebed, converted carbon dioxide (the primary atmospheric constituent of Mars) to oxygen, and even used its powerful microphones to record the sounds of Mars. Given the incredible science conducted by Curiosity and Perseverance, what are the most significant implications for the MARSE mission?

A selfie of NASA’s Perseverance rover taken in January 2023 displaying the rover with several sample tubes it has collected and dropped on the Martian surface to be picked up and returned to Earth by the Mars Sample Return mission, scheduled for the 2030s. (Credit: NASA/JPL-Caltech/Malin Space Science Systems)

“The most significant ramification of this trade study is that it should be possible to build a small rover capable of characterizing an unexplored site on Mars,” Longo tells Universe Today. “There have been several proposals for cheap Mars landers, such as SHIELD. MARSE demonstrates that it may be possible to deliver useful scientific payloads with these landers. Each MARSE rover weighs just 15 kilograms and is about the size of a microwave oven. If we can determine how to land similar rovers on Mars, that would help proliferate and democratize Mars exploration. We are already seeing a similar paradigm shift in lunar exploration thanks to the Commercial Lunar Payload Services (CLPS) program.”

Artist rendition of one of the four MARSE mission rovers that will be deployed to explore a single landing site on Mars. (Credit: Longo (2024))

While Curiosity and Perseverance have successfully explored their respective landing sites in great detail, the cost of each mission was in the billions of dollars (Curiosity: ~$2.5 billion, Perseverance: ~$2.7 billion). Therefore, the cost alone only allows for one rover per mission, and their landings occurred almost seven years apart. As noted, one of the objectives of the MARSE mission concept is to land four rovers at four separate landing sites, which are Columbia Hills, Milankovi? Crater, Mawrth Vallis, and Terra Sirenium, with Coumbia Hills being the landing site for the Spirit rover during its mission from 2004 to 2010, and the others having never been explored by landers or rovers. But how were the landing sites chosen and are other landing sites being considered?

Longo tells Universe Today, “The four landing sites are not an exclusive list. We just wanted to illustrate the range of investigations which can be conducted with this approach. All four of the listed sites have been highlighted in peer-reviewed papers and prior landing site studies, so we know that they have high scientific potential.”

Image of Columbia Hills on Mars, which is one of the potential landing sites for a MARSE rover. The white circle denotes the approximate 80-kilometer (50-mile) landing ellipse that SHIELD will use to land. (Credit: Longo (2024))

Longo continues by telling Universe Today that SHIELD will be designed to “land at any flat site on Mars below the datum (0 km of elevation on Mars; the equivalent of sea level on Earth), so you could readily swap one or more of them out for locations of your choice”, with Longo noting that one of his personal favorite landing sites would be inside Valles Marineris, which is the largest and deepest canyon in the solar system. Longo discusses the years-long research by Dr. Steven Ruff at Arizona State University, who conducted analog studies comparing hot spring deposits at Columbia Hills on Mars to similar features at the El Tatio hot spring in Chile, concluding that microbial communities could thrive at these locations.

A breakdown of the Mars Astrobiology, Resource, and Science Explorers (MARSE) mission profile and its Simplified High Impact Energy Landing Device (SHIELD) system, which could revolutionize how we search for life on Mars by using four rovers at four different landing sites. (Credit: Longo (2024))

As noted, Curiosity and Perseverance landed on Mars almost nine years apart, 2012 and 2021, respectively, but their respective missions had been in the works almost an entire decade earlier. Both rovers are part of NASA’s Mars Exploration Program, with the Curiosity rover mission having been approved in 2003 and the Perseverance rover mission having been announced in 2012. Once approved, it takes NASA years to design and build each rover, ensuring every aspect of their systems is functioning at their fullest potential before being delivered and loaded onto the launch vehicle. This includes tests designed to analyze the rovers’ endurance, exposure to harsh environments, and longevity, and many others. Therefore, if a MARSE mission were to get the green light, it could still be almost a decade of designs, builds, and tests before their microwave-sized rovers touch the surface of Mars. So, what are the next steps in terms of MARSE being approved for an actual mission?

“Regrettably, the future of MARSE and SHIELD is uncertain,” Longo tells Universe Today. “This concept was developed with the support of the SHIELD team at JPL, led by Lou Giersch and Nathan Barba. They were doing phenomenal, cutting-edge work, and I was grateful for the opportunity to work with them. Unfortunately, JPL was forced to implement massive budget cuts and layoffs last month due to uncertainty over the future of the Mars Sample Return mission, which accounts for the majority of the center’s budget. Because JPL’s future priorities are in flux, we have placed the development of the MARSE concept on hold.”

While uncertainty looms for the MARSE mission, it’s important to note that space exploration missions often take decades to go from a simple concept to real hardware, and then several more years until it’s launched. This is noted by the Curiosity and Perseverance rover missions, as it took almost a decade from the time each was approved until they landed on Mars. Moreover, it is not uncommon for mission proposals to take several attempts before they’re approved, as NASA has very stringent criteria for approving missions, including cost, timelines, science objectives, and long-term implications for science. Despite the outlook, this has not deterred Longo from continuing his work for the MARSE mission concept.

“Developing a mission concept is a rewarding experience, and it was a privilege to work on this concept with the SHIELD team,” Longo tells Universe Today. “Even if it happens a decade from now, I hope that someone will eventually implement a low-cost, multi-rover Mars geology and astrobiology mission. Following the completion of Mars Sample Return, the next logical steps in Mars exploration are to explore more of the planet, to develop a better understanding of its history, and to learn what Mars can teach us about our own planet’s past. If we want to have a thriving space program, we need to be creative and embrace bold ideas, and I love working with the scientists and engineers who are doing just that.”

Will the MARSE mission get to explore the Red Planet 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 Search for Life on Mars Could Level-Up with MARSE Mission Concept appeared first on Universe Today.



The Milky Way’s Smallest, Faintest Satellite Galaxy Found

The Milky Way has many satellite galaxies, most notably the Large and Small Magellanic Clouds. They’re both visible to the naked eye from the southern hemisphere. Now astronomers have discovered another satellite that’s the smallest and dimmest one ever detected. It may also be one of the most dark matter-dominated galaxies ever found.

The galaxy is called Ursa Major III / UNIONS 1 (UMa3/U1), and it contains very few stars. In fact, its luminosity is so low that it’s gone undetected until new, even though it’s in our neighbourhood.

The discovery is in a new paper titled “Ursa Major III/UNIONS 1: the darkest galaxy ever discovered?” The paper has been published in The Astrophysical Journal, and the lead author is Simon Smith. Smith is an astronomy graduate student at the University of Victoria, BC, Canada.

“UMa3/U1 is located in the Ursa Major (Great Bear) constellation, home of the Big Dipper. It is in our cosmic backyard, relatively speaking, at about 30,000 light-years from the Sun,” said Smith. “UMa3/U1 had escaped detection until now due to its extremely low luminosity.”

There are only about 60 stars in UMa3/U1, which barely qualifies it as a galaxy. There are star clusters with more members than that. In fact, the tiny galaxy is more in line with an open cluster in terms of number of stars.

“There are so few stars in UMa3/U1 that one might reasonably question whether it’s just a chance grouping of similar stars.”

Marla Geha, professor of astronomy and physics at Yale University

The tiny galaxy contains stars that are more than 10 billion years old and is only 10 light-years across, small for a galaxy. Its mass is also low for a galaxy. It contains just 16 times the mass of the Sun and is 15 times less massive than the faintest suspected dwarf galaxy. Those are small numbers more similar to a globular cluster, but it still might be a galaxy because of the presence of dark matter.

While stellar associations like globular clusters are more massive than this dwarf galaxy, they’re not galaxies. Astronomers think that globulars are dominated by baryonic (normal) matter processes. Ultra-faint galaxies (UFG) like this one have masses many orders of magnitude greater than their stars can account for. “Therefore, in the framework of ?CDM (Lambda Cold Dark Matter) cosmology, dwarf galaxies are thought to lie at the center of their own dark matter halos,” the research states. Astrophysicists think the dark matter haloes account for all that mass, something that globulars and other star clusters lack.

The tiny galaxy was first spotted as part of the Ultraviolet Near Infrared Optical Northern Survey (UNIONS) at Canada France Hawaii Telescope (CFHT) and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS,) both in Hawaii. Once detected, the researchers studied it in more detail with Keck Observatory’s Deep Imaging Multi-Object Spectrograph (DEIMOS). Those observations confirmed that the stars are gravitationally bound, meaning they had to be either in a cluster or a tiny galaxy.

The CFHT is at Hawaii's Mauna Kea Observatory, Hawaii, and Pan-STARRS is at the Haleakala Observatory in Hawaii. Both are key parts of UNIONS, the Ultraviolet Near Infrared Optical Northern Survey. Image Credit: UNIONS
The CFHT is at Hawaii’s Mauna Kea Observatory, Hawaii, and Pan-STARRS is at the Haleakala Observatory in Hawaii. Both are key parts of UNIONS, the Ultraviolet Near Infrared Optical Northern Survey. Image Credit: UNIONS

The galaxy’s small number of stars would make anyone question whether it can be rightly called a galaxy. Even the researchers had their doubts.

“There are so few stars in UMa3/U1 that one might reasonably question whether it’s just a chance grouping of similar stars. Keck was critical in showing this is not the case,” says co-author Marla Geha, professor of astronomy and physics at Yale University. “Our DEIMOS measurements clearly show all the stars are moving through space at very similar velocities and appear to share similar chemistries.”

This figure from the research shows the motion (L) and velocity (R) of the dwarf galaxy's member stars. In the left panel, the great region marks the motion of stars in the Milky Way and shows how the member stars (blue) are clustered together differently. In the panel on the right, the member stars are clustered together by velocity, and the empty circles are other non-member stars. Image Credit: Smith et al. 2024
This figure from the research shows the motion (L) and velocity (R) of the dwarf galaxy’s member stars. In the left panel, the great region marks the motion of stars in the Milky Way and shows how the member stars (blue) are clustered together differently. In the panel on the right, the member stars are clustered together by velocity, and the empty circles are other non-member stars. Image Credit: Smith et al. 2024

Astronomers have struggled to understand dwarf galaxies and their dark matter. For one thing, the diagnostics astronomers use, like the stellar mass-metallicity relation, leads to arguments that they’re more like star clusters than galaxies. Also, their observed properties place them at the mid-point between clusters and dwarf galaxies.

Uncertainty abounds when it comes to UMa3/U1. Somehow, this association of stars has remained intact for a long time. With such low stellar mass, the grouping should’ve been torn apart by now, its members diluted into the larger Milky Way population. The fact that it’s still together is an intriguing indication that dark matter is involved.

“The object is so puny that its long-term survival is very surprising.”

Will Cerny, co-author, Yale University

“Excitingly, a tentative spread in velocities among the stars in the system may support the conclusion that UMa3/U1 is a dark matter-dominated galaxy – a tantalizing possibility we hope to scrutinize with more Keck observations,” said Yale University graduate student Will Cerny, the second author of the study.

“The object is so puny that its long-term survival is very surprising. One might have expected the harsh tidal forces from the Milky Way’s disk to have ripped the system apart by now, leaving no observable remnant,” says Cerny. “The fact that the system appears intact leads to two equally interesting possibilities. Either UMa3/U1 is a tiny galaxy stabilized by large amounts of dark matter, or it’s a star cluster we’ve observed at a very special time before its imminent demise.”

If astrophysicists can confirm that the galaxy has dark matter, that would be a big deal. It would be more evidence in support of the Lambda Cold Dark Matter (CDM) model, the leading theory for dark matter and the Big Bang. CDM predicts that as the Milky Way formed, its gravity attracted large numbers of dwarf galaxies, much more than found so far. If this is one of them, and if the others are as difficult to detect as UMa3/U1, it supports the CDM.

But for the researchers behind the discovery, there’s more to it than just dark matter. They’ve found something unusual that’s difficult to detect. Are there more of them out there?

The ESA's Gaia mission has found many dwarf galaxies and globular clusters in the Milky Way's halo. This image from the mission's second data release shows 75 globular clusters (blue) and 12 nearby dwarf galaxies (red). But deeper observations are needed to understand the nature of the dwarf galaxies. Image Credit: ESA/Gaia/DPAC; Map and orbits: CC BY-SA 3.0 IGO LICENCE CC BY-SA 3.0 IGO or ESA Standard Licence
The ESA’s Gaia mission has found many dwarf galaxies and globular clusters in the Milky Way’s halo. This image from the mission’s second data release shows 75 globular clusters (blue) and 12 nearby dwarf galaxies (red). However, deeper observations are needed to understand the nature of the dwarf galaxies. Image Credit: ESA/Gaia/DPAC; Map and orbits: CC BY-SA 3.0 IGO LICENCE CC BY-SA 3.0 IGO or ESA Standard Licence

“Whether future observations confirm or reject that this system contains a large amount of dark matter, we’re very excited by the possibility that this object could be the tip of the iceberg – that it could be the first example of a new class of extremely faint stellar systems that have eluded detection until now,” says Cerny.

As for its origins, there are really only two options. It either formed in situ or was accreted by the Milky Way. Astronomers use metallicity and orbit to determine a dwarf galaxy’s origins, but in this case, neither measurement showed clearly that it formed in situ.

Only further observations will constrain its origins, but as it stands, the authors are leaning toward accretion. “We favour a scenario where UMa3/U1 was accreted onto the Milky Way halo,” they write in their conclusion. That scenario also supports the Lambda CDM model.

Its fate is similarly unclear. So far, it hasn’t been torn apart, which signals the presence of dark matter. But if it doesn’t have dark matter, it may be on the verge of being destroyed. We’ll have to wait and see.

For now, the object has an uncertain past and an uncertain future. But whatever it ends up being classified as, it’s something new, and that means it’s a challenge.

“This discovery may challenge our understanding of galaxy formation and perhaps even the definition of a ‘galaxy,'” says Smith.

The post The Milky Way’s Smallest, Faintest Satellite Galaxy Found appeared first on Universe Today.



Thermal Modeling of a Pulsed Plasma Rocket Shows It Should Be Possible To Create One

We’ve reported on a technology called pulsed plasma rockets (PPRs) here at UT a few times. Several research groups have worked on variations of them. They are so popular partly because of their extremely high specific impulse and thrust levels, and they seemingly solve the trade-off between those two all-important variables in space exploration propulsion systems. Essentially, they are an extremely efficient propulsion methodology that, if scaled up, would allow payloads to reach other planets in weeks rather than months or years. However, some inherent dangers still need to be worked out, and overcoming some of those dangers was the purpose of a NASA Institute for Advanced Concepts (NIAC) project back in 2020. 

Originally granted to Howe Industries, a design shop that has received several NIAC grants (including two in 2020 itself), the purpose of this project was to model the design of a fully functional PPR in modeling software to see if the necessary materials and power systems are available for a rocket that can provide 100 kN of thrust and over 5,000 seconds of specific impulse. 

In essence, a PPR takes a fuel pellet made out of some form of fissionable material (in this case, uranium), and zaps it into a plasma, then emits the plasma out the back for a forceful thrust. Rockets with this design can carry much less fuel than standard chemical rockets, but their design must be significantly larger due to the heating constraints put on the system by creating the plasma in the first place.

SciShow discusses a scaled down version of the PPR proposed in the paper.
Credit – SciShow Space

Those heating constraints were one of the Phase I NIAC study’s main focal points in 2020. In particular, this study focused on analyzing the barrel the fuel pellet is released into to see if it could withstand the extreme temperatures created by handling a plasmatized uranium pellet.

To do this modeling, the team at Howe Industries used a modeling software called MCNP6 to check where particles went in the system and thereby calculate how much heat would be collected on other parts of the system where it wasn’t desired. MCNP6 uses a Monte Carlo simulation methodology, which calculates where neutrons will be created from the fission reaction that makes the plasma and where those neutrons will impact the rest of the spacecraft.

Those plasmas would have to be created about once every second, according to the calculations done by Howe Industries, and each pulse must reach an energy level of around 1 keV – much smaller than industrial-level nuclear fission reactors but a relatively high number for a spacecraft propulsion system. That energy is turned into heat, and while some of the heat is effectively used to eject the plasmatized uranium out as a thrust propellant, the rest is absorbed by other parts of the system. 

Troy Howe, one of the paper’s authors, discusses his research into the PPR.
Credit – Interstellar Research Group YouTube Channel

The barrel was a part of that system that is particularly important in these thermal calculations. The modeled barrel was made out of low-enriched uranium but of a different type than the projectile, allowing the energy to heat the projectile and not the barrel itself. However, a small part of the barrel would be made of highly enriched uranium, allowing for rapid plasma propagation in an otherwise relatively stable system.

That’s not to say that none of the heat generated by the fission reaction would end up in the barrel. Still, by the author’s calculations as part of their final report, an active cooling system should be enough to lower the temperature to a point where at least the barrel itself wouldn’t melt. Other parts of the system, such as the nozzle and a rotating drum that helps handle the fuel pellet, will be modeled in future work.

Additional future work would include building benchtop prototypes of these systems to test them out, though the prospect of working with highly enriched uranium as part of this process seems daunting. However, NIAC hasn’t yet funded a Phase II study of the PPR system, so for now, it is resigned to a nicely modeled project and another step forward in an idea that has plenty of history. Maybe someday, it will find its time to shine.

Learn More:
Howe et al. – Pulsed plasma rocket- developing a dynamic fission process for high specific impulse and high thrust propulsion
UT – Magnetic Fusion Plasma Engines Could Carry us Across the Solar System and Into Interstellar Space
UT – Plasma Thruster Could Dramatically Cut Down Flight Times to the Outer Solar System
UT – Plasma Rocket Could Help Pick Up Space Trash

Lead Image:
Model of the PPR design proposed in the paper.
Credit – Howe et al.

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Civilizations Could Time Their Communications Based on the Movement of a Single Star

The Search for Extraterrestrial Intelligence has been ongoing for decades at this point. Despite that, we have yet to find any rock-hard evidence of a signal from an alien civilization. When asked about this, experts point out just how little of the overall signal space we’ve analyzed. A signal could be coming from anywhere in the sky, at any frequency, and might not be continuous. Constraining the “search space” could help us find a signal faster, but what could we use to constrain it? It’s hard to think like an alien intelligence, let alone to mimic them.

One of the most famous examples of the reverse of search is the Arecibo message, wherein humanity tried to announce, “We are here,” using scientific and mathematical standards like numbers and the atomic number of some elements (hydrogen and carbon, for example). Even so, it was still sent as a binary signal using a type of frequency modulation at a single point in time back in 1975. The likelihood that any civilization in the Messier 13 globular cluster, its intended target, will be able to both receive and interpret it is negligible. But it would help if they had a key to interpret it. But how can we convey a key to unlock the message without the key itself being interpretable only with the same key?

Naoki Seto of Kyoto University’s Department of Physics has spent a lot of time thinking about that question, and he came to a similar conclusion about the usefulness of scientific constants. In the past, he produced papers that suggested the time of a future binary star merger or a past supernova explosion to help narrow down a patch of sky to look at. However, with a new paper released on March 21st, he suggested a new idea – the orbital period of an exceptionally bright star around the Milky Way’s supermassive black hole.

Fraser discusses the most hyped finding of SETI so far – the WOW! signal.

The supermassive black hole at the center of our galaxy, known as Sgr A*, would be well known to any alien civilization advanced enough to send communication signals to announce their presence. It also, conveniently, has several super-bright stars that orbit it on regular periods. Dr. Seto selected one of those stars, known simply as S2.

S2 is a B-type star, is skewed toward the blue end of the stellar spectrum, and weighs in at about 15 times the mass of our own Sun. But most importantly, it is very, very bright and orbits Sgr A* with an orbital period of almost exactly 16 years. 

Those features are important because of their prominence but also because of the ease of calculations for something called the Schelling point. A Schelling point is derived from game theory – specifically, how two people can communicate about how to communicate without actually communicating. For example, someone wants to meet up with their partner but doesn’t want to tell them when or where they want to meet up. The other person is also interested in meeting up but equally interested in not communicating when or where. 

Fraser askes – are we ready to find aliens?

A Schelling point is thinking through reasonable touch points culturally to try to determine a place to meet without expressly saying it. In one example, knowing that we’re both Americans, if we were to pick one distinct time of year to meet up, and knowing that the other person is thinking the same thing, they might settle on something well known, such as midnight on New Year’s Eve. As for a place to meet, why not New York, the country’s largest city, and maybe Grand Central Station, the most common meeting place in that great city? That would be a Schelling point for two Americans, and the same inductive reasoning can be applied to communications with alien life forms.

S2 and its orbital period are something we would have in common with any alien life that develops in this galaxy – they would be able to see it from wherever they are. Dr. Seto thinks that using detailed characteristics of this one particular star, astronomers could start to search specific patches of sky for signals that use its orbital period as a basis for communication.

This is admittedly an arbitrary selection of a touch point for the Schelling point, but the general idea holds. The most likely way we can narrow down the absurd number of search parameters plaguing the search for extraterrestrial intelligence is to try to think like an alien and come up with some shared common experience that we can use as a basis to try to communicate without prior communication. It’s a tricky problem, and one that has lasted for decades, but, as with all things in science, the more people that get to thinking about them, the more likely they are to be solved.

Learn More:
Naoki Seto – A Proposal for Enhancing Technosignature Search toward the Galactic Center
UT – What is the Arecibo Message?
UT – What are the Best Ways to Search for Technosignatures?
UT – The 2nd Annual Penn State SETI Symposium and the Search for Technosignatures!

Lead Image:
Image of the galactic center. For the interferometric GRAVITY observations the star IRS 16C was used as a reference star, the actual target was the star S2. The position of the centre, which harbours the (invisible) black hole known as Sgr A*,with 4 million solar masses, is marked by the orange cross.
Credit – ESO / MPE / Gillessen et al.

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Thursday, March 28, 2024

Lunar Night Permanently Ends the Odysseus Mission

On February 15th, Intuitive Machines (IM) launched its first Nova-C class spacecraft from Kennedy Space Center in Florida atop a SpaceX Falcon 9 rocket. On February 22nd, the spacecraft – codenamed Odysseus (or “Odie”) – became the first American-built vehicle to soft-land on the lunar surface since the Apollo 17 mission in 1972. While the landing was a bit bumpy (Odysseus fell on its side), the IM-1 mission successfully demonstrated technologies and systems that will assist NASA in establishing a “sustained program of lunar exploration and development.”

After seven days of operation on the lunar surface, Intuitive Machines announced on February 29th that the mission had ended with the onset of lunar night. While the lander was not intended to remain operational during the lunar night, flight controllers at Houston set Odysseus into a configuration that would “call home” if it made it through the two weeks of darkness. As of March 23rd, the company announced that their flight controllers’ predictions were correct and that Odie would not be making any more calls home.

The company started listening for a wake-up signal from Odysseus on March 20th, when they projected that there was enough sunlight in the lander’s vicinity. At the time, it was thought that this could potentially charge Odysseus‘ power system, allowing it to activate its radio and reestablish contact with Houston. However, three days later, at 10:30 AM Central Standard Time (08:30 AM PST; 11:30 AM EST), flight controllers determined that the lander was not charging up after it completed its mission.

Image from the IM-1 Odysseus lander after it soft landed on the lunar surface. Credit: Intuitive Machines

This consisted of the Nova-C spacecraft making its inaugural soft landing on the Moon, the first time an American spacecraft has done so in over 50 years. The IM-1 mission was also the first time a spacecraft used methalox – the combination of liquid methane and liquid oxygen (LOX) – to navigate between the Earth and the Moon. While the IM-1 was not expected (or intended) to survive the lunar night, the data acquired by this mission could prove useful as the company continues to improve the lunar landing systems to deliver payloads to the Moon.

One of the company’s main objectives is to develop heat and power sources that can “keep systems from freezing during the lunar night.” This technology will greatly extend the life of lunar surface missions and facilitate the buildup of infrastructure on the Moon’s surface. A second Nova-C lander with the IM-2 mission will launch aboard a Falcon 9 no earlier than December 2024. This mission will land a drill and the Polar Resources Ice Mining Experiment-1 (PRIME-1) mass spectrometer near the south pole of the Moon.

This NASA payload will demonstrate the feasibility of In-Situ Resource Utilization (ISRU) and measure the volatile content of subsurface samples. ISRU and the presence of water are vital to the creation of a lunar base and the ability to send crews to the lunar surface well into the foreseeable future. A third mission (IM-3) is scheduled for early 2025, which will carry four NASA payloads to the Reiner Gamma region of the Moon, a rover, a data relay satellite, and secondary payloads to be determined. All three launches were contracted as part of NASA’s Commercial Lunar Payload Services (CLPS) program.

In addition, the IM-1 mission controllers and company managed to have a final farewell with the Odysseus mission before nightfall and the depletion of its battery power. On February 22nd, the lander transmitted a final image (shown below), which mission controllers in Houston received by February 29th. The image, Intuitive Machines said in a statement, “showcases the lunar vista with the crescent Earth in the backdrop, a subtle reminder of humanity’s presence in the universe. Goodnight, Odie. We hope to hear from you again.”

The last image sent by the IM-1 Odysseus mission on Feb. 22nd, 2024. Credit: Intuitive Machines

Further Reading: Intuitive Machines

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