In June 2008, the Gamma-ray Large Area Space Telescope began surveying the cosmos to study some of the most energetic phenomena in the Universe. Shortly after that, NASA renamed the observatory in the Fermi Gamma-ray Space Telescope in honor of Professor Enrico Fermi (1901-1954), a pioneer in high-energy physics. During its mission, Fermi has addressed questions regarding some of the most mysterious and energetic phenomena in the Universe – like gamma-ray bursts (GRBs), cosmic rays, and extremely dense stellar remnants like pulsars.
Since it began operations, Fermi has discovered more than 300 gamma-ray pulsars, which have provided new insights into the life cycle of stars, our galaxy, and the nature of the Universe. This week, a new catalog compiled by an international team contains the more than 300 pulsars discovered by the Fermi mission – which includes 294 confirmed gamma-ray-emitting pulsars and another 34 candidates awaiting confirmation. This is 27 times the number of pulsars known to astronomers before the Fermi mission launched in 2008.
Pulsars are a type of neutron star, which are what remains when stars undergo gravitational collapse near the end of their lives and go supernova. These and other neutron stars are the densest objects that astronomers can study directly (as opposed to black holes, which can only be studied indirectly). Pulsars are so-named because they possess strong magnetic fields that force their radiation into narrow beams emitted from their poles. Combined with how they spin rapidly on their axis, this produces a lighthouse-like effect that astronomers can detect light-years away.
A dozen radio telescopes worldwide monitor thousands of pulsars regularly, and astronomers are constantly looking for new candidates within gamma-ray sources discovered by Fermi. Of the 3,400 known pulsars, most were detected via radio waves and located within our Milky Way galaxy. Only about 10% of pulsars also emit gamma rays, while others have been identified that emit gamma rays but not radio emissions. David Smith, research director at the Bordeaux Astrophysics Laboratory in Gironde (part of CNRS), was the study coordinator. As he explained in a NASA press release:
“Pulsars touch on a wide range of astrophysics research, from cosmic rays and stellar evolution to the search for gravitational waves and dark matter. This new catalog compiles full information on all known gamma-ray pulsars in an effort to promote new avenues of exploration.”
As Smith and his colleagues indicate in the catalog, fewer than a dozen gamma-ray pulsars were known when Fermi launched in 2008. Moreover, the extent and diversity of the population and its role in Galactic dynamics were subject to debate. But thanks to the mission and its primary instrument, the Large Area Telescope (LAT), scientists quickly learned that the gamma-ray population is large and varied and that these pulsars are the dominant gamma-ray source in the billion-electronvolt (GeV) class in the Milky Way.
Fermi also detected the first gamma-ray pulsar beyond the Milky Way in 2015, located in the neighboring Large Magellanic Cloud (LMC). This effectively demonstrated that flares from supermagnetized neutron stars can be detected in distant galaxies. In addition, its measurements have provided important limits on new theories of gravity and the nature of Dark Matter. They also revealed a previously-unknown component in our galaxy known as the Fermi Bubbles, a structure spanning 50,000 light-years that is likely the result of radiation outbursts from the supermassive black hole (SMBH) at the center of our galaxy (Sagitarrius A*).
The First FERMI LAT Catalog (LAT-1), released in 2010, contained 46 pulsars based on six months of data. The second catalog, based on the first three years of data, grew that number to 132. This third installment is based on 12 years of data that characterizes the 294 confirmed gamma-ray pulsars and 33 millisecond pulsars (MSPs), which have not yet shown gamma-ray pulsations but likely will once accurate rotation ephemerides are established. Before Fermi, astronomers did not know if MSPs were visible at high energies, but these now account for about half of the overall catalog.
“More than 15 years after its launch, Fermi remains an incredible discovery machine, and pulsars and their neutron star kin are leading the way,” said Elizabeth Hays, the mission’s project scientist at NASA’s Goddard Space Flight Center.
When the Vera C. Rubin Observatory comes online in 2025, it will be one of the most powerful tools available to astronomers, capturing huge portions of the sky every night with its 8.4-meter mirror and 3.2-gigapixel camera. Each image will be analyzed within 60 seconds, alerting astronomers to transient events like supernovae. An incredible five petabytes (5,000 terabytes) of new raw images will be recorded each year and made available for astronomers to study.
Not surprisingly, astronomers can’t wait to get their hands on the high-resolution data. A new paper outlines how the huge amounts of data will be processed, organized, and disseminated. The entire process will require several facilities on three continents over the course of the projected ten-year-long survey.
Detailed cut-away render of the telescope model showing the inner workings. Credit: LSST Project/J. Andrew
The Rubin Observatory is a ground-based telescope located high in the Chilean Andes. The observatory’s 8.4-meter Simonyi Survey Telescope will use the highest resolution digital camera in the world that also includes the world’s largest fish-eye lens. The camera is roughly the size of a small car and weighs almost 2,800 kg (6,200 lbs). This survey telescope is fast-moving and will be able to scan the entire visible sky in the southern hemisphere every four nights.
“Automated detection and classification of celestial objects will be performed by sophisticated algorithms on high-resolution images to progressively produce an astronomical catalog eventually composed of 20 billion galaxies and 17 billion stars and their associated physical properties,” write Fabio Hernandez, George Beckett, Peter Clark and several other astronomers in their preprint paper.
The main project for Rubin Observatory is the Legacy Survey of Space and Time (LSST) and researchers anticipate this project will gather data on more than 5 million asteroid belt objects, 300,000 Jupiter Trojans, 100,000 near-Earth objects, and more than 40,000 Kuiper belt objects. Since Rubin will be able to map the visible night sky every few days, many of these objects will be observed hundreds of times.
Because of the telescope’s repeated observations, the enormous amount of data will help calculate the positions and orbits of all these objects.
Images flow from the Summit Site, where the telescope is located in Chile, to the Base Site and then to the three Rubin Data Facilities which collectively provide the computational capacity for processing the images taken by the Observatory for the duration of the survey. Credit: Vera Rubin Observatory.
Images and data will immediately flow from the telescope to the Base Facility and Chilean Data Access Center in La Serena, Chile and then go to the three Rubin data facilities on dedicated high-speed networks connecting the sites: the French Data Facility CC-IN2P3 in Lyon, France, the UK Data Facility, IRIS network, in the United Kingdom and the US Data Facility and Data Access Center at SLAC National Accelerator Laboratory in California, USA. There is also a Headquarters Site at the Association of Universities for Research in Astronomy (AURA) in Tucson, Arizona, USA.
Once images are taken, they will be processed according to three different timescales: prompt, daily, and annually. The Hernandez et al paper outlines how raw images collected each observing night will be quickly processed (within 60 seconds), and objects that have changed brightness or position will generate and emit alerts for “transient detection.” For this process known as Prompt Processing, there will be no proprietary period associated with alerts, and they will be available to the public immediately, since the goal is to quickly transmit nearly everything about any given event, to enable quick classification and decision making. Scientists estimate Prompt Processing could generate millions of alerts per night.
Daily products, released within 24 hours of observation, will include the images from that night. The annual campaigns will reprocess the entire image dataset collected since the beginning of the survey.
For each data release, there will be raw and calibration images in addition to science-ready images which have been processed with updated scientific algorithms. There will also be catalogs with the properties of all the astrophysical objects detected.
“The volume of released data products generated by the annual processing of the accumulated set of raw images is on average 2.3 times the size of the input dataset for that year and is estimated to reach more than one hundred petabytes by the end of the survey,” the astronomers wrote. They also said that over the ten year-long survey the volume of data released for science analysis is estimated to increase by one order of magnitude.
Illustration of the conceptual design of the LSST Science Pipelines for image processing. Credit: Hernandez et al.
The Rubin Observatory will utilize several kinds of data products and services for archiving and dissemination of the data to the various science collaborations. The paper says the Rubin LSST “Science Pipelines” are composed of about 80 different kinds of tasks, which are all implemented on top of a common algorithmic code base and specialized software. There is a feature called the Data Butler, which is the software system that abstracts the data access details (including data location, data format and access protocols).
Each year a data release will be produced and made available to science collaborations for use in studies in four main science pillars: probing dark matter and dark energy, taking inventory of Solar System objects, exploring the transient optical sky and mapping the Milky Way.
This annual release will allow all the survey images taken to date to be reprocessed, combined and automatically measured to yield an increasingly deep picture of the whole Southern sky, and a growing catalog of astronomical objects that captures how each one has changed over time. This annual data processing will be run at the three data facilities, with the final dataset assembled at SLAC and made available to astronomers and physicists via the Rubin Science Platform.
Right now, it is expected that Rubin Observatory data will become fully public after two years. The issue of how the public data can be accessed and how this access could be funded is still in the works.
Our search for life beyond Earth is still in its infancy. We’re focused on Mars and, to a lesser extent, ocean moons like Jupiter’s Europa and Saturn’s Enceladus. Should we extend our search to cover more unlikely places like molecular clouds?
The idea that life could survive on other worlds like Mars or Europa gained vigour in the last few decades. Scientists found Earth life persisting in some extreme environments: hydrothermal vents, Antarctic pack ice, alkaline lakes, and even inside nuclear reactors.
Parallel to these discoveries, astronomers found life’s chemical building blocks in space. They’ve found amino acids inside meteorites, organic chemistry in the interstellar medium (ISM,) and polycyclic aromatic hydrocarbons (PAHs) in molecular clouds.
The discovery of extremophiles and life’s building block in space suggests we should widen the scope of our search for life. Should molecular clouds be one of our targets?
This is a two-panel mosaic of part of the Taurus Giant Molecular Cloud, the nearest active star-forming region to Earth. The darkest regions are where stars are being born. Inside these vast clouds, complex chemicals are also forming. Image Credit: Adam Block /Steward Observatory/University of Arizona
Molecular clouds are massive clouds of gas and dust out of which stars form. They’re called molecular clouds because they’re mostly molecular hydrogen, though they can contain many different compounds. Though the clouds are filamentary in nature, they do form clumps of greater density that sometimes become stars.
Could life exist in such a tenuous environment? One researcher thinks the question is worth exploring. In a paper titled “Possibilities for Methanogenic and Acetogenic Life in a Molecular Cloud,” Chinese researcher Lei Feng examines the idea that life began in space as methanogens or acetogens, bacteria that produce methane and acetic acid as byproducts. These could be the precursors to Earth’s life, according to Feng.
“If methanogenic life exists in the presolar nebula, then it may be the ancestor of Earth’s life, and there are already some tentative evidences by several molecular biology studies,” Feng writes. (English is clearly not Feng’s first language, but it’s easy to see what he’s getting at.)
Feng’s exploration rests on the idea of panspermia. Panspermia is the idea that life exists throughout the Universe and was spread around by asteroids, comets, even space dust and minor planets. The history of life on Earth suggests that panspermia could’ve played a role, but we just don’t know. The idea was entirely speculative until scientists started finding life’s building blocks in space.
Panspermia is the idea that life is spread throughout the galaxy, or even the Universe, by asteroids, comets, and even minor planets. Credit: NASA/Jenny Mottor
The main problem with life in molecular clouds concerns the temperature. It can be as low as 10 Kelvin or -263 Celsius. That’s extremely cold, even for Earth’s extremophiles. There’s also no solid surface, but that might not be enough to prohibit life.
A key factor in life, as far as we understand it, is that cells need liquid to go about their metabolic business. Without water, cell membranes would lack structure, so there’d be no way to keep the inside parts in and the outside stuff out. But does the liquid have to be water? Could it be liquid hydrogen? Methane? We don’t know.
“Hydrogen molecules maintain a liquid state between 13.99 K and 20.27 K, and it happens to be the typical temperature of molecular clouds,” Feng writes. “If we suppose that life in molecular clouds has a cell-like membrane structure and the hydrogen molecules (the main component of molecular clouds)
enriched therein, the hydrogen pressure is also enlarged, and hydrogen could maintain a liquid state in molecular cloud life.”
Feng explains that liquid hydrogen in molecular cloud life (MCL) could play the same role that water plays in Earth life. “A liquid hydrogen state is an ideal place for biochemical reactions similar to the water environment of cells on Earth,” he states.
This is a Hubble composite image of the Chamaeleon I cloud complex. If Feng’s hypothesis is correct, life could have originated in molecular clouds like this one. Image Credit: NASA, ESA, K. Luhman and T. Esplin (Pennsylvania State University), et al., and ESO; Processing: Gladys Kober (NASA/Catholic University of America)
Life needs energy, too, and Earth life is almost entirely based on sunlight. Molecular clouds can be cold, dark places. How would Feng’s MCL acquire energy?
“How does molecular cloud life obtain enough energy? Previously, the author proposed cosmic-ray-driven bioenergetics powered by the ionization of hydrogen molecules,” Feng writes, referring to his previous paper on the same subject. There may be other possibilities.
Life and reproduction require energy transformation. Earth life relies on respiration. The respiration can be either aerobic or anaerobic, meaning it either uses oxygen or another electron acceptor.
Methanogenic bacteria were some of Earth’s first life, and they produce methane as a byproduct in hypoxic (low oxygen) conditions. In the process, they generate free energy needed for life. Scientists have wondered if methanogens could live on Saturn’s moon Titan. Could it be surviving in molecular clouds?
“Methanogens could live on Titan, then can they live in molecular clouds? Here we will discuss such probability and calculate the releases of free energy for methanogenic life in the environment of molecular clouds,” Feng writes.
Some researchers think that life could exist on Saturn’s moon Titan. Titan’s atmosphere is 5% methane, and it’s so cold that liquid hydrocarbons exist on its surface. If life can exist here, can it exist in molecular clouds? Image Credit: By NASA/JPL/University of Arizona/University of Idaho, Public Domain.
According to Feng, the calculations show that methanogenesis in molecular clouds can produce enough free energy to fuel life. “From the calculations, we found that the reaction of carbon monoxide, carbon
dioxide or acetylene with hydrogen molecules releases sufficient Gibbs free energy to ensure the survival of molecular cloud life,” Feng explains.
These activities could even produce biosignatures, according to the author. “The consumption of carbon compounds by life activities may affect the distribution of organic molecules. It might be a possible trace signal of molecular cloud life,” he writes.
Feng’s hypothesis is that life could’ve begun in molecular clouds and spread to Earth and elsewhere. He says that methanogenic and acetogenic life could be the ancestors of Earth’s LUCA, the Last Universal Common Ancestor. LUCA is the common ancestral cell from which life’s three domains, Bacteria, the Archaea, and the Eukarya, originated.
It never pays to discard an idea too hastily. There’s a lot we don’t know about Life, the Universe, and Everything. Can we afford to rule Feng’s idea out? Unfortunately for Feng, his work lacks the participation of other researchers, which can be a signal that something’s not quite right. Some single-author papers have made important contributions to science, mostly in the past. But they’re becoming increasingly rare.
Feng’s hypothesis is an interesting, outside-the-box idea. Outside-the-box thinking doesn’t always lead directly to a new understanding, but it can spur new pathways of thinking. However, Feng’s work runs into some roadblocks. Molecular clouds only last about 100 million years. Is that enough time? Also, LUCA is still just a hypothetical organism.
For now, Feng’s paper is in pre-print, meaning it hasn’t undergone peer review and hasn’t been accepted for publication anywhere. It’s hard to say what the wider scientific community will have to say about it.
When NASA’s Lucy mission flew past asteroid Dinkinesh on November 1, 2023, it made the surprising discovery the asteroid had a tiny moon. Then came another surprise. This wasn’t just any moon, but a contact binary moon, where two space rocks are gently resting against each other. Of course, this new and unique moon needed a name, so the International Astronomical Union (IAU) has just approved approved “Selam,” which means peace in Ethiopia’s language.
But, everything’s connected here. Dinkinesh is the Ethiopian name for the Lucy fossil, and Selam is named after another fossil from the same species of human ancestor.
The Lucy mission is named after the hominid skeleton fossil called Lucy that was discovered in Ethiopia in 1974. Lucy (in turn, named after the Beatles song, “Lucy in the Sky With Diamonds) is estimated to be 3.18 million years old. This fossilized human ancestor has provided unique insight into humanity’s evolution. Likewise, the Lucy mission will revolutionize our knowledge of planetary origins and the formation of the Solar System.
The fossil Selam was discovered in 2000 in Dikika, Ethiopia, and belonged to a 3-year-old girl of the same species as Lucy. Even though this fossil is referred to as Lucy’s baby, the “baby” actually lived more than 100,000 years before Lucy.
“It seemed appropriate to name its satellite in honor of another fossil that is sometimes called Lucy’s baby,” said Raphael Marshall of the Observatoire de la Côte d’Azur in Nice, France, who originally identified Dinkinesh as a potential target of the Lucy mission.
The flyby of Dinkinesh served as a test for Lucy’s instruments on its way to the Trojan asteroids, a large group of asteroids that share the same orbit as Jupiter.
Moonlet rise over Dinkinesh as seen from NASA’s Lucy spacecraft, taken within a minute of closest approach. Credit: NASA/Goddard/SwRI/Johns Hopkins APL/NOAO
This first asteroid encounter for the Lucy mission really surprised everyone. Not only was there the surprise of the previously hidden contact binary, but the surprisingly high-resolution images revealed boulder-strewn surface on both small worlds. Up close, 790 meter-wide Dinkinesh looks a lot like 101955 Bennu, visited by OSIRIS-REx. NASA says that we can expect to see more images of the flyby with additional processing soon, saying that the team has completed downlinking the data from Lucy’s first asteroid encounter and is continuing to process it.
The Dinkinesh encounter was added in January of this year as an in-flight test of the spacecraft’s systems and instruments, and in a recent Lucy blog post by Katherine Kretke of the Southwest Research Institute, she says all systems performed well.
“The tools and techniques refined with data from this encounter will help the team prepare for the mission’s main targets, the never-before-explored Jupiter Trojan asteroids,” Kretke wrote. “In addition to the images taken by Lucy’s high-resolution L’LORRI camera and its Terminal Tracking Cameras (T2Cam), Lucy’s other science instruments also collected data that will help scientists understand these puzzling asteroids.”
The mission plan for Lucy is currently to visit 9 more asteroids over the next decade in 6 separate encounters. After an Earth gravity assist in December 2024, the spacecraft will return to the main asteroid belt where it will encounter asteroid Donaldjohanson in April 2025. Lucy will pass through the main belt and reach the mission’s primary targets, the Jupiter Trojan asteroids, in 2027.
Astronomers have imaged dozens of protoplanetary discs around Milky Way stars, seeing them at all stages of formation. Now, one of these discs has been found for the first time — excitingly — in another galaxy. The discovery was made using the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile along with the , which detected the telltale signature of a spinning disc around a massive star in the Large Magellanic Cloud, located 160,000 light-years away.
“When I first saw evidence for a rotating structure in the ALMA data I could not believe that we had detected the first extragalactic accretion disc, it was a special moment,” said Anna McLeod, an associate professor at Durham University in the UK and lead author of the study published in Nature. “We know discs are vital to forming stars and planets in our galaxy, and here, for the first time, we’re seeing direct evidence for this in another galaxy.”
McLeod and her fellow researchers were doing a follow-up study on a system named HH 1177, which was located deep inside a gas cloud in the Large Magellanic Cloud LMC). In 2019, the researchers reported that in using the Very Large Telescope, they observed a jet emitted by a fledgling but massive star with a mass 12 times greater than our Sun. This was the first time such a jet has been observed in visible light outside the Milky Way, as they are usually obscured by their dusty surroundings. However, the relatively dust-free environment of the LMC allowed for HH 1177 to be observed at visible wavelengths. At nearly 33 light-years in length, it is one of the longest such jets ever observed.
This dazzling region of newly-forming stars in the Large Magellanic Cloud (LMC) was captured by the Multi Unit Spectroscopic Explorer instrument on ESO’s Very Large Telescope. The relatively small amount of dust in the LMC and MUSE’s acute vision allowed intricate details of the region to be picked out in visible light. Credit: ESO, A McLeod et al.
“We discovered a jet being launched from this young massive star, and its presence is a signpost for ongoing disc accretion,” McLeod said in an ESO press release. But to confirm that such a disc was indeed present, the team needed to measure the movement of the dense gas around the star.
The gas motion indicated that there is a radial flow of material falling onto a central disk-like structure. In their new observations, the team found that the disk exhibits signs of Keplerian rotation – which is a disk of material that obey’s Kepler’s laws of motion due to the dominance of a massive body at its center. Their observations revealed that “the rotating toroid [was] feeding an accretion disk and thus the growth of the central star,” the McLeod and team wrote in their paper. “The system is in almost all aspects comparable to Milky Way high-mass YSOs (young stellar objects) accreting gas from a Keplerian disk.
As matter is pulled towards a growing star, it cannot fall directly onto it; instead, it flattens into a spinning disc around the star. Closer to the center, the disc rotates faster, and this difference in speed is the clear evidence to show astronomers an accretion disc is present.
“The frequency of light changes depending on how fast the gas emitting the light is moving towards or away from us,” said Jonathan Henshaw, a research fellow at Liverpool John Moores University in the UK, and co-author of the study, in the ESO press release. “This is precisely the same phenomenon that occurs when the pitch of an ambulance siren changes as it passes you and the frequency of the sound goes from higher to lower.”
Massive stars like HH 1177 live fast and die hard. In the Milky Way, stars like this are challenging to observe because they are often clouded from view by the dusty material from which they form — which also obscures the disc that might be shaping around them.
“They form in heavily embedded regions full of gas and dust, such that the accretion phase typically occurs before the star has time to become exposed due to stellar feedback, whether internal or external,” the team wrote in their paper. “The primary reason for the lack of observations of extragalactic accretion disks around forming stars has been the limited spatial resolution of both ground- and space-based observatories.”
But the Large Magellanic Cloud is fundamentally different from because the stars that form there have a lower dust content than in the Milky Way. Because of that HH 1177 is no longer cloaked in its early dust cloud, providing astronomers an unobstructed view, even though it is so far away.
The researchers said the instruments on ALMA enables the high-sensitivity and high-angular-resolution observations needed to detect and resolve rotating circumstellar gas in the LMC.
“We are in an era of rapid technological advancement when it comes to astronomical facilities,” McLeod says. “Being able to study how stars form at such incredible distances and in a different galaxy is very exciting.”
China’s Zhurong rover was equipped with a ground-penetrating radar system, allowing it to peer beneath Mars’s surface. Researchers have announced new results from the scans of Zhurong’s landing site in Utopia Planitia, saying they identified irregular polygonal wedges located at a depth of about 35 meters all along the robot’s journey. The objects measure from centimeters to tens of meters across. The scientists believe the buried polygons resulted from freeze-thaw cycles on Mars billions of years ago, but they could also be volcanic, from cooling lava flows.
A wireless camera took this ‘group photo’ of China’s Tianwen-1 lander and rover on Mars’ surface. Credit: Chinese Space Agency
The Zhurong rover landed on Mars on May 15, 2021, making China the second country ever to successfully land a rover on Mars. The cute rover, named after a Chinese god of fire, explored its landing site, sent back pictures — including a selfie with its lander, taken by a remote camera – studied the topography of Mars, and conducted measurements with its ground penetrating radar (GPR) instrument. Zhurong had a primary mission lifetime of three Earth months but it operated successfully for just over one Earth year before entering a planned hibernation. However, the rover has not been heard from since May of 2022.
Researchers from the Institute of Geology and Geophysics under the Chinese Academy of Sciences who worked with Zhurong’s data said the GPR provides an important complement to orbital radar explorations from missions such as ESA’s Mars Express and China’s own Tianwen-1 orbiter. They said in-situ GPR surveying can provide critical local details of shallow structures and composition within approximately 100-meter depths along the rover’s traverse.
a, Topographic map of Utopia Planitia, showing the landing sites of the Zhurong rover, the Viking 2 lander and the Perseverance rover. The ?4?km elevation contour is shown. Four local regions (c–f) with polygonal terrain are marked with white squares. b, The Zhurong rover traverse from Sol 11 through Sol 113 (HiRISE image: ESP_073225_2055). Green segments denote the wedges of buried polygons recognized from Fig. 2 (P1–P16). Purple segments denote the interiors of the polygons. c–f, Four representative HiRISE images of polygons in Utopia Planitia whose locations are marked in a: PSP_002202_2250 (c), PSP_006962_2215 (d), PSP_002162_2260 (e) and PSP_003177_2275 (f). Note the range of spatial scales for the sizes of the polygons. The average diameters of polygons shown in c–f are calculated in Extended Data Fig. 6. Credit for HiRISE images: NASA/JPL/University of Arizona.
Utopia Planitia is a large plain within Utopia, the largest recognized impact basin on Mars (also in the Solar System) with an estimated diameter of 3,300 km. In total, the rover traveled 1,921 meters during its lifetime.
The researchers, led by Lei Zhang, wrote in their paper published in Nature, that the rover’s radar detected sixteen polygonal wedges within about 1.2?kilometers distance, which suggests a wide distribution of similar terrain under Utopia Planitia. These detected features probably formed 3.7 – 2.9 billion years ago during the Late Hesperian–Early Amazonian epochs on Mars, “possibly with the cessation of an ancient wet environment. The palaeo-polygonal terrain, either with or without being eroded, was subsequently buried” by later geological processes.
Schematic model of the polygonal terrain formation process at the Zhurong landing site. a, The origination of thermal contraction cracking on the surface. b, The formation of cracks infilled by water ice or soil material, causing three types of polygonal terrain (ice-wedge, composite-wedge and sand-wedge polygons). c, The stabilization of the surface polygonal terrain in the Late Hesperian–Early Amazonian, possibly with the cessation of an ancient wet environment. d, The palaeo-polygonal terrain, either with or without being eroded, was subsequently buried by deposition of the covering materials in the Amazonian. The Mars surface image was acquired by the Navigation and Terrain Camera (NaTeCam). Credit: Zhang et al.
The buried polygonal terrain requires a cold environment, the researchers wrote, that might be related to water/ice freeze–thaw processes in southern Utopia Planitia on early Mars.
“The possible presence of water and ice required for the freeze–thaw process in the wedges may have come from cryogenic suction-induced moisture migration from an underground aquifer on Mars, snowfall from the air or vapor diffusion for pore ice deposition,” the paper explains.
While the new paper indicates that the most likely possible formation mechanisms would be soil contraction from wet sediments that dried, producing mud-cracks, however, contraction from cooling lava could have also produced thermal contraction cracking.
Either way, they note that a huge change in Mars’ climate was responsible for the polygon’s formation.
“The subsurface structure with the covering materials overlying the buried palaeo-polygonal terrain suggests that there was a notable palaeoclimatic transformation some time thereafter,” the researchers said.
Ever want to play a game of cosmic billiards? That’s commonly how the DART mission was described when it successfully changed the orbit of a near-Earth asteroid last year. If you want an idea of how it works, just Google it and an Easter egg from the search giant will give you a general idea. But DART was more like trying to brute force a billiards break – there are many other things you can do with a set of asteroids and impactors on the galactic stage. One of the more interesting is to try to force two asteroids together to form a “contact binary” – the goal of a mission design put forward by a group of scientists from Cornell in a recent paper in Acta Astronautica.
Colby Merill and his colleagues at Cornell’s Mechanical and Aerospace Engineering department first explain why such a mission would be a good idea. Contact binaries are defined as a system when two objects are so close together that their surfaces touch. Typically, astronomers think of the objects as a pair of stars, but asteroids can also form contact binaries.
Recent estimates put the total number of contact binaries as high as 30% of all small solar system bodies, including famous ones like Arrokoth and 67P/Churyumov-Gersasimenko. That means if there are any potentially hazardous asteroids we aren’t yet aware of, there’s a fair chance it’s actually a contact binary.
Fraser discusses another potential DART successor.
Such a configuration presents a problem for planetary defense operators. Understanding where to hit a binary to deflect it makes the math much harder. Moreover, we’ve never seen one of these systems form to understand its underlying mechanisms. The standard model of this process is known as the Binary Yarkovsky-O’Keefe-Radzievskii-Paddack (BYORP) effect, by which the two asteroids, which usually begin in a standard, non-touching binary system, end up having their gravities draw each other together and touch without the catastrophic impact that would be typical of large bodies at higher speeds.
Setting up a contact binary through the BYORP effect would require a separate mission design. According to the paper, a good first effort would be to smack the asteroids into each other using an impactor. There are several advantages to this. A big one is flight heritage – the mission could use a slightly modified version of DART and a coupled observer satellite that could watch the slow-motion impact.
How slow that impact is will have a significant impact on the success of the mission. Hit the billiard ball too hard, and it will smash into its companion and cause a potentially devastating chain reaction. Hit it too softly, and there might not be enough force to push the two objects together. Plenty of math, including simulations of the forces of ejecta fragments, would go into the planning stage of any such mission.
Fraser also discusses the aftermath of the DART impact.
Those simulations require you to know some features of the planned targets, though, and the Cornell researchers have identified one. Known in strikingly formal near-asteroid parlance as (350751) 2002 AW, this system’s primary comes in at about 230 m, with a secondary partner measuring about 50 m. One potential advantage of a mission to this system is that the 50 m size of its smaller object is the minimum size limit for possible future planetary defense missions, allowing the mission to emulate a potential real planetary defense scenario.
Plenty of observation will need to take place to effectively plan where best to hit the pair, though, and with how much force to do so. The paper requests plenty of ground-based observational support, including density and orbital measurements. However, it’s unclear if there’s enough interest in the project yet to warrant diverting those resources to this new effort.
There’s also additional work to do, including developing a plan for how the observational satellite could avoid the debris cloud that will form after the impact. Another potential research area is initiating a contact using a gravity tug to force a sped-up BYORP effect.
For now, these ideas remain on the drawing board. But it’s nice to see how successful missions like DART can inspire even more ambitious ones in the future. Maybe someday, our skill at cosmic billiards will grow to include an ability to do trick shots, too.
When the Space Age dawned in 1957, there were only two players: the USA and the USSR. The USA won the space race by being first to the Moon, though the USSR enjoyed its own successes. But here we are only a few decades later, and the USSR appears to be fading away while China is surging ahead.
Nothing’s more emblematic of China’s surge than its Tiangong space station.
China is sometimes secretive about its space activities. But not when it comes to Tiangong. China is sharing some images of the space station captured by their taikonauts on Shenzhou-16. Shenzhou is the spacecraft that transports crew to and from the space station, and 16 is the current mission.
“It has made history by realizing the Chinese nation’s millennium-long dream of flying to the stars, of which we, as Chinese, are all profoundly proud.”
John Lee, Chief Executive of the Hong Kong Special Administrative Region
These are our first high-resolution images of Tiangong, and the China Manned Space Agency released them at a press conference on Tuesday, November 28th.
China began launching different modules to the space station in 2021, starting with the Tianhe core module. Tianhe provides life support and living quarters for the space station’s crew, as well as navigation, guidance, and orientation for the station.
This rendering shows the Tianhe core module in space. Tianhe was the first module in the Tiangong space station. Image Credit: By Shujianyang – Own work, CC BY-SA 4.0, https://ift.tt/afIJZDE
Three more modules follow the Tianhe core: Wentian (2022), Mengtian (2022), and Xuntian in 2024. Wentian contains a laboratory and also fulfills other functions. Mengtian also contains research facilities, while Xuntian is the Chinese Survey Space Telescope (CSST). The CSST is an optical-ultraviolet telescope that China says will outperform the Hubble.
The CSST will co-orbit with Tiangong and will periodically dock with the space station.
Another image of Tiangong, China’s space station. It’s in Low Earth Orbit between 340 and 450 km (210 and 280 mi) above the surface. Image Credit: China Manned Space Agency.
The China Manned Space Agency (CMSA) released the images at a press conference in Hong Kong. At the conference, the Chief Executive of the Hong Kong Special Administrative Region, John Lee, spoke about the CMSA and Tiangong.
“It has made history by realizing the Chinese nation’s millennium-long dream of flying to the stars, of which we, as Chinese, are all profoundly proud. Through the delegation’s visit, Hong Kong people can share the nation’s pride in China’s manned space development from close range and develop a deeper understanding of the country’s developments in aerospace technologies. The visit exemplifies the affection and support of the Central People’s Government for the Hong Kong Special Administrative Region,” Lee said.
This graphic shows the configuration of the Tiangong Space Station. Image Credit: By Shujianyang – Own work, CC BY-SA 4.0, https://ift.tt/FpqtmCf
China needs its own space station in part because the US Congress banned China from playing any role in the ISS. In fact, Congress prohibited any official American contact with the entire Chinese space program. That was due to “National Security” concerns, which often means spying but could mean anything. So, China built their own.
China’s list of reasons for building a space station mirrors any nation’s list of reasons: to gain experience in spacecraft rendezvous, permanent human operations in orbit, long-term autonomous spaceflight of the space station, regenerative life support technology and autonomous cargo and fuel supply technology. It’s also a platform for developing technologies for further exploration of the Solar System.
This is the third of three new images of the Tiangong space station released by the China Manned Space Agency. Image Credit: China Manned Space Agency.
China is inviting private space companies to take part in the Tiangong mission to help drive innovation and the development of their own space industry. They’re also considering space tourism.
Yang Liwei, China’s first taikonaut in space, says it’s just a matter of time before tourists will be able to visit Tiangong. “It is not a matter of technology but of demand,” Yang told Chinese media last year. “And it can be realized within a decade as long as there is such demand.”
For there to be space tourists, there have to be people with a lot of money. But communism is supposed to prevent the accumulation of wealth, and everything is supposed to belong to everyone. But that’s a political discussion.
China has earned the right to boast about and enjoy its success. Decades ago, during the space race, China was mired in trouble. The Cultural Revolution was in full swing, and Mao Zedong was purging the remnants of capitalism from China. There was chaos, armed struggles, and political upheaval.
Fast forward to now, and China, for all intents and purposes, is a different country. It’s an industrial and economic powerhouse, and we have to acknowledge that space is open to all nations with the resources to reach it. China is making great strides with Tiangong and all their other efforts aimed at the Moon and Mars. Once they have their own space telescope, will they really be playing catch up anymore?
The space race between the USA and the USSR helped define the age we live in. But the page has turned on that. Now it’s the USA and China that are vying for supremacy.
Tiangong is not only a symbol of China’s rise, but a functioning technological artifact of it.
Space exploration is always changing. Before February 2021 there had never been a human made craft flying around in the atmosphere of another world (other than rocket propelled landers arriving or departing). The Mars Perseverance rover changed that, carrying with it what can only be described as a drone named Ingenuity. It revolutionised planetary exploration and now, China are getting in on the act with a proposed quadcopter for a Mars sample return mission.
Our exploration of Mars has generally been limited to orbiters, landers and rovers. The orbiters are fantastic at getting planet wide data or data covering huge swathes of land and the landers are great at getting surface detail, even analysing surface material. The rovers added an extra dimension by being able to explore the landing area but generally, the rovers were slow and unable to traverse significant distances. They were also unable to move over very uneven terrain giving them limited capability.
Mars Perseverance Rover (Credit : NASA)
When Perseverance landed it took with it the Ingenuity drone or more correctly it was classed as a helicopter. Its wingspan was 1.2m from tip to tip of the rotor blades and weighed in at 4 pounds (although on Mars it weighed 1.5 pounds). Whilst its range was only 300m it proved it could be done and since its deployment has completed 66 flights, covering a total of 14.9km.
A paper recently published by the Harbin Institute of Technology and the China Academy of Space Technology proposed a quadcopter for use on Mars that would, unlike Ingenuity, be capable of collecting a sample weighing up to 100g and return it to the lander. The key challenge to achieve this is the rarefied nature of the Martian atmosphere. It is less than 1% of that on Earth and as a result, the lift generated by a rotor blade is significantly lessened. To enable sufficient lift, the blades are oversized by Earth standards.
Alternative solutions to drones were explored from earlier designs like the aeroplane based ‘Astroplane’ with a wingspan of 21m or the ‘MAP MarsFlyer’ with a wingspan of 1.73m. Both styles were discounted due to construction availability of take off and landing areas. The team concluded rotorcraft were the correct configuration and set themselves to design something that could retrieve and transport samples for return missions to Earth.
The paper provides detailed design schematics of both flight (including autonomous flight) systems, rotor configuration, mechanical arm, imaging technology and the avionics system. The described MarsBird V11 is very much just on the drawing board at the moment and is not slated for any mission yet but it is exciting to think the future of Mars exploration is from the Martian air.
As our newest, most perceptive eye on the ongoing unfolding of the cosmos, the James Webb Space Telescope is revealing many things that were previously unseeable. One of the space telescope’s science goals is to expand our understanding of how stars form. The JWST has the power to see into the cocoons of gas and dust that hide young protostars.
It peered inside one of these cocoons and showed us that what we thought was a single star is actually a binary star.
The JWST’s image of the Herbig Haro object 797 (HH 797) is the telescope’s Picture of the Month.
Herbig-Haro objects are luminous patches of nebulosity associated with young protostars. These stars are still gathering mass, a stage that can last about 500,000 years. As the protostar gathers mass, in-falling gas generates shocks on the star’s surface. So, while protostars haven’t begun their life of fusion, they still release energy. In a Herbig-Haro object, the energy that lights it up comes from twin jets of ionized gas coming from the star.
Astronomers know of more than 1000 Herbig-Haro objects in the Milky Way. The Hubble Space Telescope captured this image of the Herbig-Haro object HH 24 in the constellation Orion. HH 24 has the telltale twin jets and illuminated nebulosity of Herbig-Haro objects. Image Credit: HST/NASA
Astronomers have found hundreds of HH objects in the Milky Way, and they’re common in star-forming regions. The jets of partially ionized gas travel at hundreds of kilometres per second, slamming into nearby gas clouds and lighting them up. Most HH objects are within 3.26 light-years (one parsec) of the protostar emitting the jets.
HH objects don’t last long, only a few tens of thousands of years, which is a proverbial blink of an eye in astronomy. Astronomers can see them visibly change as they travel away from their source into the interstellar medium (ISM). The ISM can be clumpy, and the HH can fade in some parts and brighten in others as the jets encounter more diffuse and more dense regions of gas.
HH 797 doesn’t advertise itself in optical light. Instead, molecular hydrogen, carbon monoxide, and other molecules are excited by the energetic jets and emit infrared light. The JWST was built to scrutinize infrared light like this, which brings HH 797’s details into view.
The colours in the image come from different molecules present in the gas clouds. Not only are there molecular hydrogen and carbon monoxide, but iron, methane, and polycyclic aromatic hydrocarbons—a potential building block of life—are also present.
Molecules excited by the turbulent conditions, including molecular hydrogen and carbon monoxide, emit infrared light that Webb can collect to visualize the structure of the outflows. NIRCam is particularly good at observing the hot (thousands of degrees Celsius) molecules that are excited as a result of shocks. Image Credit: JWST/CSA/ESA/NASA
Research using ground-based observations showed that the gas associated with HH 797 is moving at different speeds. Most of the red-shifted gas moving away from us is in the bottom right of the image. But most of the blue-shifted gas moving toward us in the bottom left. Research also found a velocity gradient across the gas so that at any given distance from the star, the gas on the eastern end of the red-shifted jet is more red-shifted than the gas on the western edge. Astronomers chalked it up to rotation in the outflow.
But with its exceptional infrared acuity, the JWST has revealed a second protostar hiding inside the gas and dust. So what astronomers thought was a single outflow is actually two parallel outflows with their own shocks coming from two separate stars. So the velocity asymmetries are because astronomers were actually measuring two different outflows.
The source is in the bottom right small dark region, and the JWST image shows that it’s, in fact, two sources. So rather than a single protostar being responsible for what we see, there are two protostars at work.
This shouldn’t come as a surprise. As many as half of the Milky Way’s stars are in binary pairs or even multiple groups. It only makes sense that some of the HH objects we can see are, in fact, binary HH objects.
In 1950, while sitting down to lunch with colleagues at the Los Alamos Laboratory, famed physicist and nuclear scientist Enrico Fermi asked his famous question: “Where is Everybody?” In short, Fermi was addressing the all-important question that has plagued human minds since they first realized planet Earth was merely a speck in an infinite Universe. Given the size and age of the Universe and the way the ingredients for life are seemingly everywhere in abundance, why haven’t we found any evidence of intelligent life beyond Earth?
This question has spawned countless proposed resolutions since Fermi’s time, including the infamous Hart-Tipler Conjecture (i.e., they don’t exist). Other interpretations emphasize how space travel is hard and extremely time and energy-consuming, which is why species are likely to settle in clusters (rather than a galactic empire) and how we are more likely to find examples of their technology (probes and AI) rather than a species itself. In a recent study, mathematician Daniel Vallstrom examined how artificial intelligence might be similarly motivated to avoid spreading across the galaxy, thus explaining why we haven’t seen them either!
The Hart-Tipler Conjecture originated in 1975 when astronomer (and white nationalist) Michael Jart wrote a paper titled “An Explanation for the Absence of Extraterrestrials on Earth.” At the core of Hart’s argument is the notion that any ETC that arose in the Milky Way in the past would have had ample time to develop interstellar travel and establish outposts of its civilization in other star systems. These outposts would eventually send their own ships outward, leading to the creation of a Galactic civilization that covered the majority of the Milky Way.
Where is Everybody?
Based on his calculations, Tipler determined that a civilization limited to a modest fraction of the speed of light (10%) could accomplish this within just 650,000 years – long before life and human civilization arose on Earth. Given the fact that no evidence of any civilization existed (what Hart called “Fact A”) means that there were no ETCs and humanity was alone in the Universe. In 1980, physicist and cosmologist Frank Tipler took things further in his paper “Extraterrestrial Intelligent Beings Do Not Exist,” where he employed refined calculations and the Copernican Principle.
Also known as the Cosmological Principle, this axiom states that neither Earth nor humanity are in a privileged or unique position to view the Universe. In other words, our planet, our system, and our species are representative of the norm. In this vein, Tipler theorized that an ETC would be assisted by self-replicating robotic explorers (von Neumann probes) that would spread from system to system, facilitating the arrival of settlers later. As he wrote:
“In addition to a rocket technology comparable to our own, it seems likely that a species engaging in interstellar communication would possess a failure sophisticated computer technology… I shall therefore assume that such a species will eventually develop a self-replicating universal constructor with intelligence comparable to the human level… and such a machine combined with present-day rocket technology would make it possible to explore and/or colonize the Galaxy in less than 300 million years.“
No Organics, Robots!
The idea that humanity is not likely to come into contact with an alien species but could learn of their existence through their robotic emissaries is a foregone conclusion among many SETI researchers. And it certainly makes sense. Why send a crewed mission on a multi-generational interstellar voyage fraught with hazards and no guarantee of success when you can send self-replicating robots? In addition to not being vulnerable to cosmic radiation, these probes could expand outwards ad infinitum, carrying messages of greetings to anyone they encounter.
Far from being a matter of theory, proponents of this idea point toward our own history of launching probes into deep space. Since 1972, humanity has sent five probes that are currently (or destined to be) in interstellar space: Pioneer 10 and 11,Voyager 1 and 2, and New Horizons. The possibility that extraterrestrials may someday intercept these deep-space missions was strongly considered, leading to the creation of the Pioneer Plaque and the Voyager Golden Record. Per the Copernican Principle, the fact that humanity has sent five probes destined for interstellar space in just fifty years means it is likely that other species have been doing the same for much longer.
“SETI’s traditional approach, however, remains the equivalent of waiting for your phone to ring. To receive an electromagnetic signal, we need the sender to transmit it exactly a light-travel-time ago with similar communication technologies to those we developed over the past century. The odds of this happening are mind-bogglingly long... The longer we persist, the more often we are likely to send craft out into interstellar space. And the opposite logic holds true: any civilization similar to ours that managed to last for millions of years could well have sent out billions of such craft. It is high time scientists looked deliberately for them.”
Of course, this raises the question: if we’re likely to find bits of an intelligent civilization’s technology rather than members of a civilization itself, why haven’t we?
It Ain’t Easy Being Type III!
Addressing Hart’s “Fact A,” many proposed resolutions to the Fermi Paradox questioned the notion that extraterrestrial civilizations would attempt to spread across our galaxy – something the Hart-Tipler Conjecture treats as a foregone conclusion. This includes “Percolation Theory,” which Geoffrey A. Landis presented in a 1993 paper where he argued that the laws of physics would impose limits on the extent of a species’ interstellar expansion. Instead of a uniformity of expansion, species would be more likely to “percolate” outward, which would be subject to expansion and contraction.
A key point in Landis’ study is that there would be no “uniformity of motive” among extraterrestrial civilizations, with some choosing to venture out and others opting to “stay at home.” Another proposed resolution was advanced by Serbian astronomer and astrophysicist Milan M. Cirkovic in his 2008 study, “Against the Empire.” Using two models for determining the behaviors of an extraterrestrial civilization – what he called the “Empire-State” or the “City-State” model – Cirkovic questioned whether a species would invariably be expansion-driven or optimization-driven.
In 2019, Prof. Adam Frank and colleagues from NASA’s Nexus for Exoplanetary Systems Science (NExSS) released a study where they argued that settlement of the galaxy would also occur in clusters because of inhospitable environments. Named in honor of the novel Aurora by Kim Stanley Robinson, Frank and his colleagues simulated how a civilization’s expansion across the galaxy would be limited by the “Aurora Effect” – where habitable planets are not hospitable due to the presence of indigenous species.
However, for his study, Vallstrom emphasized another source of motivation for robotic explorers: morality. Not morality in the traditional sense, mind you, but in the sense of decisions that ensure long-term survival. As he explained:
“With an evolutionary approach, the basis of morality can be explained as adaptations to problems of cooperation. With ‘evolution’ taken in a broad sense, evolving AIs that satisfy the conditions for evolution to apply will be subject to the same cooperative evolutionary pressure as biological entities… Diminishing beneficial returns from increased access to material resources also suggests the possibility that, on the whole, there will be no incentive to colonize entire galaxies, thus providing a possible explanation of the Fermi paradox.”
Central to Vallstrom’s study is the notion that advanced societies will eventually give rise to super-AIs as a function of evolution – as they ought to be safer, more efficient, more flexible, and fitter. This is especially true where space exploration is concerned, which entails considerable hazards for biological entities. He further argues that the Fermi Paradox is only paradoxical if one assumes that societies and super-AIs are “exhaustively expansive,” which is debatable for three reasons. The first has to do with material resource utilization, beyond which accumulating more will offer diminishing returns.
This diminishing effect, says Vallstrom, will eventually lead societies to adopt cooperation in the form of trade, collaboration, and redistribution. Taking this a step further, Vallstrom argues that cooperative societies and super-AIs would need a good reason to pursue exponential growth and settle an entire galaxy, eventually culminating in a Kardashev type III society. In addition, he posits that evolution would not necessarily favor rapid or exponential reproduction, as evidenced by three points. First, there is how entities living on a surface can only spread so fast as a function of time for mathematical reasons, as each entity takes up a certain amount of space, and others must travel farther to find more.
The Allen Telescope Array searches for alien technosignals. Credit: Seth Shostak, SETI Institute
Second, Vallstrom argues how biological evolution emphasizes “fitness,” where species continue to evolve to adapt to (and fill niches) in their environment. This does not necessarily favor very fast reproduction, which can be maladaptive when numbers outstrip resources. Third, there are cultural evolution and other changes to consider, as exemplified by human fertility rates. “[T]he number of births peaked in 2012 and is projected to continue to get smaller,” he writes, “hence the number of children peaked in 2017 and is projected to continue to get smaller, and (hence) human population is projected to decrease within a few generations.”
So… Where are all the Robots?
Lastly, there is the question of where we should look for super-AIs or robotic space explorers. First, Vallstrom states plainly that advanced civilizations and super-AIs would not be likely to contact us since they would be unlikely to benefit from it. Simply put, a highly advanced species would have little reason to contact a less advanced species, not unless the cost of doing so was small or there was mutual benefit to be had. “For example, we probably wouldn’t fault old societies or super-AIs for not helping, say, the dinosaurs or the Neanderthals,” he writes.
So, if we assume we will not hear from them anytime soon, how could humanity search for evidence of advanced intelligence and its AI progeny? This is where the question of motivations and morality really comes into play. Suppose we also accept that advanced civilizations and super-AI are not motivated by the desire for exponential growth, eventually leading to a Kardashev type III society. In that case, we must consider other, more pragmatic concerns. For example, Vallstrom ventures that super-AIs might be concerned about the eventual fate of the Universe, known as the “heat death” scenario.
According to the predominant cosmological model – the Lambda Cold Dark Matter (LCDM) model – the Universe will eventually expand to the point that the Cosmic Microwave Background (CMB) will recede into the radio end of the spectrum and that anything beyond our galaxy will be beyond the event horizon (and therefore, invisible). Therefore, Super-AIs may be motivated to prepare for this eventuality (since it will also mean their death) by grouping galaxy clusters together and extending the life of their stars. As Vallstrom wrote, this represents a prediction that may one day be testable for SETI researchers:
“[I]t would, possibly, be better to have fewer and larger clusters rather than more and smaller clusters, all other things being equal… [A]s a hypothetical example, if we observe configurations – at lower redshifts, but not at very high ones – that in the far future will result in useful clusters, and to a larger extent than what we would otherwise expect, then perhaps we might consider the possibility that those observations could be signs of super-AI actions. Further, if super-AIs will succumb to heat death, then possibly they could try to reduce entropy waste, e.g. maybe by affecting star formation.”
For decades, the Search for Extraterrestrial Intelligence (SETI) has been guided by a handful of established principles. These include the notion that intelligent life will be subject to the same physics and technological principles as humanity (the Copernican Principle), subject to a spectrum of motivations, and likely be older and more advanced than humanity. After sixty years of surveys, two things remain unchanged: one, we haven’t found any evidence that we are not alone in the Universe, and two, we have barely scratched the surface.
In the meantime, coming up with testable predictions and ideas that challenge old assumptions gives us something to look forward to. And thanks to next-generation telescopes, advanced analytics, and growing support for SETI projects, we may finally get a chance to test them all!
