Every year, NASA releases a detailed simulation of the Moon that shows how it will change through the year. They produce a couple of versions that show how it appears from the northern and southern hemisphere and others that highlight different features. Not only does it show the phases through the year but it also shows the change in size as its completes its orbit. The change in apparent size of the Moon is a result of its elliptical orbit so that it can appear up to 30% brighter.
The Moon is Earth’s only permanent natural satellite. It has captivated humans for thousands of as it orbits at an average distance of 384,400 kilometres. It plays a key role in shaping our tides through its gravitational pull. The lunar surface is a desolate, rocky world with colossal mountains, and plains known as maria. It has no atmosphere and so experiences extreme temperature shifts, from intense solar heating in the day to freezing cold at night. Over the centuries, it has inspired countless myths and driven exploration that has culminated in the Apollo missions and soon Artemis.
Global map of the Moon, as seen from the Clementine mission, showing the lunar near- and farside. If we’re going back to the Moon, we’ll need a Lunar GPS. Credit: NASA.
One of the most well known aspects of the Moon are the lunar phases. The phases of the Moon represent its motion around the Earth and its changing appearance when viewed from Earth. The cycle lasts about 29.5 days and is known as a lunar month. It begins with a new moon when the Moon lies approximately between Earth and the Sun and appears nearly invisible as we look at the night time hemisphere.
The bright sunlit crescent contrasts with the darker lighting of twice-reflected light supplied by sunlight reflecting off our own planet. Credit: Bob King
As the cycle continues the crescent appears, getting larger and larger marking the waxing crescent phase. Eventually it leads to a first quarter phase when half of the Moon appears illuminated. It increases through the waxing gibbous phase before reaching full moon. The cycle then reverses through the waning phases to new moon again.
The phases appear nicely in the video from NASA but what is also apparent is the gentle rocking of the Moon. Known as libration, it means we get to see slightly more than 50% of the lunar surface, 59% over time. The phenomenon occurs due to the axial tilt of the Moon and its elliptical orbit. It can be categorised as three different types; longitudinal (caused by changes in Moon’s orbital speed,) latitudinal (caused by tilt in the Moon’s axis) and diurnal (caused by Earth’s rotation and a slight shift in position of observer.)
The video simulation produced by NASA has been created from images taken by the Lunar Reconnaissance Orbiter (LRO.) It has been in orbit since the summer of 2009 and has produced images of unprecedented quality. Using advanced instruments, it has mapped the surface in high detail, revealing detailed topography, temperature, and geological maps. It has identified landing sites, especially near the poles, where water ice may exist, and has captured images of some of the Apollo landing sites.
Artist’s rendering of Lunar Reconnaissance Orbiter (LRO) in orbit. Credit: ASU/LROC
The animation shows the phases, and libration at hourly intervals until the end of 2025. One month is compressed down into about 24 seconds to give a comprehensive view of the year ahead.
Before the decade is out, as part of the Artemis Program, NASA plans to send astronauts to the Moon for the first time since the Apollo Era. To realize this goal, they have contracted with commercial space industries to develop all the necessary components. This includes the Space Launch System (SLS) and the Orion spacecraft that will take the Artemis astronauts to the Moon. There’s also the Lunar Gateway and the Artemis Base Camp, the infrastructure that will facilitate regular missions to the Moon after 2028.
In between, NASA has also partnered with companies to develop the Human Landing Systems (HLS) that will transport the Artemis astronauts to the lunar surface and back. This includes the Starship HLS SpaceX is currently developing for NASA, which will rendezvous with the Orion spacecraft in lunar orbit and allow the Artemis III astronauts to land on the Moon (which will take place no sooner than September 2026). In a series of newly-updated images, SpaceX has provided artistic renders of what key moments in this mission will look like.
Artist’s rendering of the Starship tanker transferring propellant to a Starship depot in orbit. Credit: SpaceX
The renderings include a Starship tanker docking with a Starship propellant depot in Low-Earth Orbit (LEO), shown above. These elements are crucial to SpaceX’s long-term plans to send payload and crews to the Moon and Mars, which require that the Starship refuel in orbit so that it can make a trans-lunar injection (TLO) or trans-Mars injection (TMI). For the Artemis missions, this will allow the Starship HLS to reach lunar orbit, where it will rendezvous with the Orion spacecraft. Once there, the Orion will dock with the Starship HLS (shown below), and two Artemis crew members will transfer to the HLS.
The Orion spacecraft docking with the Starship HLS in lunar orbit. Credit: SpaceX
At this juncture, the two astronauts will take the Starship HLS to land near the Moon’s southern polar region (shown below). Similar to how the Starship has conducted many landings here on Earth, this will consist of the spacecraft firing two of its Raptor engines to make a powered descent (shown below). Once the spacecraft safely lands on the Moon (shown at top), the two astronauts will descend to the surface using the spacecraft’s elevator (shown at bottom) and spend approximately a week exploring the South Pole-Aitken Basin, collecting samples, performing science experiments, and observing the Moon’s environment.
Artist’s rendering of the Starship HLS making a braking burn to land on the Moon. Credit: SpaceX
This mission will help pave the way towards creating a lunar settlement in the area, taking advantage of the abundant water ice observed in permanently shadowed regions (PSRs) – i.e., the many craters that dot the Moon’s south pole. While these surface operations take place, the other Artemis crew will await them in orbit. The Starship HLS and its two crewmembers will then launch into lunar orbit and rendezvous with the Orion spacecraft one last time. After returning to the Orion, the entire crew will return home, leaving the Starship HLS in orbit.
Two Artemis III astronauts using the Starship HLS elevator to descend to the surface. Credit: SpaceX
In preparation for the Artemis III mission, SpaceX will perform an uncrewed landing demonstration mission on the Moon. NASA is also working with SpaceX to further develop the HLS to meet the extended requirements for the Artemis IV mission, which is scheduled to launch no sooner than September 2028. This mission will see a crew rendezvous with the Artemis Gateway, which will be launched ahead of time, then land on the lunar surface and conduct extensive science operations. This will include field geology experiments, deploying instruments, and collecting more samples.
The Arecibo Message, transmitted on November 16th, 1974, from the Arecibo Observatory, was humanity’s first true attempt at Messaging Extraterrestrial Intelligence (METI). The message was a simple pictorial signal in binary code composed by famed astronomer and SETI researcher Frank Drake (inventor of the Drake Equation) with the assistance of Sagan and other prominent astronomers. The message was and was aimed toward Messier 13 (NGC 6205 or “The Great Hercules Cluster”), a globular star cluster located about 25,000 light-years from Earth in the constellation of Hercules.
In 2018, in preparation for the 45th anniversary of the historic broadcast, the Arecibo Message Global Challenge was launched. Student teams were tasked with designing a new message that could be sent to space, and by August 2020, the Boriken Voyagers team was recognized as the winner of the competition. Unfortunately, the Observatory collapsed on December 1st, 2020, and the message was never sent. To commemorate the 50th anniversary of the Arecibo Message, the Boriken Voyagers have shared “The Last Arecibo Message.”
The Boriken Voyagers team consists of eight students from the University of Arecibo Mayagüez Campus (RUM) and the Planetary Habitability Laboratory (PHL) at the University of Puerto Rico at Arecibo. Boriken is the name for Puerto Rico in the language of the Indigenous Taino/Arawakan people. The group is led by Kelby D. Palencia-Torres, a student at RUM and PHL who specializes in the study of the gas and dust surrounding galactic disks – aka. the Circumgalactic Medium.
The Original Message
The Arecibo Message was organized by Drake in the early 1970s as the first campaign to compose a message destined for space. The effort relied on Arecibo’s megawatt transmitter attached to its 305-meter (1000-foot) antenna to send a 20-gigawatt omnidirectional broadcast. The M13 cluster was selected because of the number of stars (about 300,000) and the cluster’s age (11.65 billion years). This made it seem a likely place to host an extraterrestrial civilization. The message was not intended as an invitation to talk nearly as much as a demonstration of human technological capabilities and scientific knowledge.
The message was transmitted on November 16th, 1974, at a frequency of 2380 MHz and an effective bandwidth of 10 Hz. The message was transmitted at a frequency-shifting rate of 10 bits per second and lasted less than three minutes. It consisted of a 1679-binary digit picture (210 bytes) – the product of two prime numbers – arranged rectangularly into 73 lines of 23 characters per line (also prime numbers). The use of prime numbers was deliberate since mathematics is considered the only “universal language” and easier for an alien civilization to decode.
They conveyed a series of scientific, geographical, biological, and astronomical information in different colors. These included:
A counting scheme of 1 to 10 (white)
The atomic numbers for hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up DNA (purple)
The chemical formula of the four purines and pyrimidine bases that make up DNA (green)
An image of the DNA double helix and an estimate of the number of nucleotides (blue and white, respectively)
A stick figure of a human being (red), our average dimensions (blue/white), and the human population of Earth (white)
A depiction of the Solar System, indicating that the message is coming from the third planet (yellow)
A schematic of the Arecibo Observatory and its dimensions (purple/white and blue)
Fifty years after the Arecibo Message was sent, its legacy lives on. Universe Today recently caught up with the Boriken Voyagers to learn more about the original message and their updated version. The team members included Kelby D. Palencia-Torres, Cesar F. Quinones-Martinez, Javier A. Garcia Sepulveda, Luis R. Rivera Gabriel, Lizmarie Mateo Roubert, German Vazquez Perez, and Abel Mendez.
Q: Why does the Arecibo Message endure 50 years later?
Germán Vázquez Pérez: “Even 50 years later, and despite the loss of the Arecibo Observatory, the Arecibo Message continues its journey through the vastness of space, waiting to be intercepted by potential civilizations. It’s a bittersweet feeling. The message remains an example of what humanity can achieve, but we no longer possess the same capability to receive a potential reply or transmit another message with such power and significance. At least for the moment.”
Kelby Palencia-Torres: “The significance of the Message is that it represents humanity, and it is the first intentional message of our existence in the cosmos. The message compels curiosity, and it’s our first step to answering the old question if we are alone in the universe.”
Lizmarie Mateo Roubert: “The Arecibo Message can represent the hope people working in the scientific community have in answering questions about the Universe and all the efforts they have put in throughout the years.”
Cesar Quinones-Martinez: “The Arecibo Message has fascinated many throughout the decades, bringing a lot of debate as to whether or not we should actively contact other extraterrestrial civilizations. Arecibo and the Arecibo Message for Puerto Rico represent a collective curiosity in space exploration, as for many students on the island, visiting Arecibo becomes a key motivator to beginning their STEAM journey. It represents a bold step into the unknown, where our curiosity takes us to make new discoveries. “
Q: How has the field of SETI/METI changed since?
Cesar Quinones-Martinez: “The SETI and METI initiatives both have seen improvements to their capabilities as technology improves. Bigger, more sensitive detectors bring us closer to receiving any artificial signal, while better transmitters could allow for future messages that can better retain their information while passing through gas clouds or other mediums. While the Arecibo Message was designed to showcase Arecibo’s capabilities, current METI projects are more rigorous with what they want to communicate. We do not know the intentions of the recipient of our message, and measures must be taken to be direct with what we say.”
Kelby Palencia-Torres: “With METI, we are more cautious with the content included in the messages. Some sci-fi series like the ‘3 Body Problem’ play a negative role in how METI is perceived outside the scientific community.”
Q: What was it like to compete in the Arecibo Message Global Challenge?
Kelby Palencia-Torres: “The New Arecibo Message Global Challenge was an intriguing and daring competition. To partake and enlist in the challenge, one had to solve a riddle. After this first stage of the challenge, we had to solve a puzzle where the situation was similar to that of the movie Contact. We had to decode a message and identify the location of said message. Once proven to solve the puzzle, we passed to the last stage, where we had to develop the New Arecibo Message. As part of the challenge of the message, we had to consider the energy used to produce the signal and transmit it, choose a location visible to the Arecibo Telescope, and the hardest part … fully create the content of the message itself.”
Lizmarie Mateo Roubert: “At the time, this was truly the most difficult part of the challenge we had encountered so far. Back in 2018, most of us were just beginning our undergraduate degrees and some of the information we needed to keep in mind whenever we were to develop a message in a way that could be encoded eventually proved to be a bit of a struggle. With the help of other professionals in the field and professors on our university campus, we were then able to fully understand how to properly develop this message and the different conditions and capabilities we had to keep in mind so the message could be successfully sent and deciphered.”
Luis Rivera: ‘It proved to be a space for great professional and personal growth for me. The difficulty behind solving the problems and creating something new that t underscored the need for teamwork in all aspects of science, and helped me grow closer to people I call my friends today.’
Cesar Quinones-Martinez: ‘The Arecibo global Competition consisted of 3 stages to highlight important stages of making the message: interpretation, decoding a received message, and finally writing our New Arecibo Message. The first stage showed how clever message design can contain a lot of information about the subject material. Imagine a pixelated image of a human sent at a certain frequency. How do you figure out the human’s average height? The key is the frequency, which corresponds to a specific wavelength so that by counting the pixels, you can approximately obtain the height.
“However, is that all the information you can extract from the image? Knowing the size of the pixels, you can figure out the ratio of the head to the arms, legs, and abdomen, communicating more about humans without added complexity. The second stage gave us a scenario with a received message that we needed to decode. The team regularly pitched different ideas on what aspects of the signal were important to decode, which was useful to the design of the new Arecibo Message in the final stage. The competition was a great exercise in thinking outside the box and looking at different perspectives, showing the nuance of communicating efficiently when the turnaround time can be centuries.’
Aerial view of the damage to the Arecibo Observatory following the collapse of the telescope platform on December 1st, 2020. Photo courtesy of Deborah Martorell.
The Last Arecibo Message
Lizmarie Mateo Roubert: “The content of the Last Arecibo Message contains information about humanity’s knowledge of mathematics, science, and astronomy. The first two sections include the numbers from 1 to 10 and the arithmetic symbols including the equal sign. We included mathematical and physical constants such as pi, the Euler constant, the speed of light, the Planck constant, and the Stefan-Boltzmann constant. Adding these constants in our message helps us with a variety of assumptions regarding the recipient’s understanding of the universe..”
Germán Vázquez: “We also wanted to share astronomical aspects of our galaxy, solar system, and earth-moon system to pinpoint our location in the universe. The image of the Milky Way Galaxy is presented (up to scale) with the distance from the Galactic center to our solar system.
“The Arecibo Message, sent in 1974, served as a direct inspiration for the next section of our message, our Solar System. However, we wanted to enhance some aspects to make it more descriptive and accurate. We included our Moon and Saturn’s rings, enhanced the sizes of the gas giants, and excluded Pluto, which is now considered a dwarf planet.
“The Earth-Moon system was also implemented in our message, considering the impact our natural satellite has had in shaping humanity, influencing our calendars, producing ocean tides, and understanding celestial mechanics. Lastly, our depiction of a human being, the average height, and the population in 2020 were also included, alluding to the original message.”
Kelby Palencia-Torres: “The purpose of the message is to continue the legacy of the Arecibo Observatory and the Original message by Frank Drake. Our message sums up humanity’s curiosity and wanting to explore the universe together.”
Q: “What significance could this have for the ongoing debate concerning METI?“
Kelby Palencia-Torres: “The message we constructed for the Arecibo Message Global Challenge was to commemorate and demonstrate the importance the original had. Currently, our message does not have plans to be transmitted. But it showcases the innate curiosity and feelings we have to see if we are alone. Our message will go to the list of messages built with METI purposes and show the interest in taking the first step in communicating with other intelligence.
“One of the assumptions we use in our paper can also back up METI since other civilizations with similar capabilities to our civilization will face the same constraints as SETI. Whoever listens will need resources, energy, and telescope time to look for techno signatures in their sky. Assuming that other civilizations have a greater technological feat than us, it would mean giving access to resources and a really big and sensitive radio telescope to a being from this advanced civilization to search for techno signatures, and it all would be reduced to be lucky enough to be looking at the right moment and time to receive a one time signal that is not continuous such like the original Arecibo message or the wow signal.”
Despite 90 years of research, the nature and influence of Dark Matter continue to elude astronomers and cosmologists. First proposed in the 1960s to explain the rotational curves of galaxies, this invisible mass does not interact with normal matter (except through gravity) and accounts for 85% of the total mass in the Universe. It is also a vital component in the most widely accepted cosmological model of the Universe, the Lambda Cold Dark Matter (LCDM) model. However, according to new research, the hunt for DM could be over as soon as a nearby star goes supernova.
Currently, the axion is considered the most likely candidate for DM, a hypothetical low-mass particle proposed in the 1970s to resolve problems in quantum theory. There has also been considerable research into how astronomers could detect axions by observing neutron stars and objects with powerful magnetic fields. In a recent study supported by the U.S. Department of Energy, a team of astrophysicists at the University of California Berkeley argued that axions could be discovered within seconds of detecting gamma rays from a nearby supernova explosion.
The study was conducted by researchers at the Berkeley Center for Theoretical Physics (BCTP) and a member of the Lawrence Berkeley National Laboratory’s (LBNL) Theoretical Physics Group. The paper that describes their findings was published on November 19th in the journal Physical Review Letters. As they argue, axions would be produced in copious quantities during the first 10 seconds after a massive star undergoes core collapse and becomes a neutron star. These axions would then escape and be transformed into high-energy gamma rays in the star’s intense magnetic field.
For decades, the search for Dark Matter focused on MAssive Compact Halo Objects (MACHOs). When they failed to materialize, physicists began to consider Weakly Interacting Massive Particles (WIMPs) as the most likely candidate but also failed to find anything tangible. This led to axions becoming the most widely accepted candidate, an elementary particle that fits within the Standard Model of Particle Physics and resolves several unresolved questions in Quantum Mechanics – including a Theory of Everything (ToE).
The strongest candidate for axions is the quantum chromodynamics (QCD) axion, which theoretically interacts with all matter, though weakly. As previous research has shown, axions will occasionally turn into photons in the presence of a strong magnetic field that can be detected. However, such detections would be very challenging since it would require that the supernova be nearby (within the Milky Way or one of its satellite galaxies). In addition, observable supernovae are rare, occurring once every few decades.
The last time astronomers observed this phenomenon was in 1987 when a Type II supernova (SN1987A) appeared suddenly in the Large Magellanic Cloud (LMC), roughly 168,000 light-years from Earth. At the time, NASA’s Solar Maximum Mission (SMM) was observing the LMC but wasn’t sensitive enough to detect the predicted intensity of gamma rays. Benjamin Safdi, a UC Berkeley associate professor of physics and senior author of a paper, explained in a recent UC Berkeley News statement:
“If we were to see a supernova, like supernova 1987A, with a modern gamma-ray telescope, we would be able to detect or rule out this QCD axion, this most interesting axion, across much of its parameter space — essentially the entire parameter space that cannot be probed in the laboratory, and much of the parameter space that can be probed in the laboratory, too. And it would all happen within 10 seconds.”
Illustration of NASA’s Fermi Gamma-ray Space Telescope at work. Credit: NASA GSFC
Through a series of supercomputer simulations that used SN1987A to constrain higher mass axions, Safdi and his colleagues determined that Type II supernovae simultaneously produce bursts of gamma rays and neutrinos. They further noted that the gamma rays produced would depend on the axions’ mass and only last 10 seconds after the neutron star forms. After that, the production rate would drop dramatically. This means a gamma-ray space telescope must be pointed toward the supernova at precisely the right time.
The Fermi Gamma-ray Space Telescope is currently the only observatory capable of detecting cosmic gamma-ray sources. Based on its field of view, scientists estimate that Fermi would have about a one-in-ten chance of spotting a supernova. To that end, the team proposes that we create a next-generation gamma-ray telescope known as the GALactic AXion Instrument for Supernova (GALAXIS). Said Safdi:
“This has really led us to thinking about neutron stars as optimal targets for searching for axions as axion laboratories. Neutron stars have a lot of things going for them. They are extremely hot objects. They also host very strong magnetic fields. The strongest magnetic fields in our universe are found around neutron stars, such as magnetars, which have magnetic fields tens of billions of times stronger than anything we can build in the laboratory. That helps convert these axions into observable signals.”
As they note, a single detection of gamma rays would pinpoint the mass of an axion over a huge range of theoretical masses and allow for laboratory experiments to refocus their efforts on confirming this mass. Even a lack of detection would mean that scientists could eliminate a large range of potential masses for the axion, which would narrow the search for Dark Matter considerably. In the meantime, Safdi and his colleagues hope the Fermi telescope will catch a lucky break.
“The best-case scenario for axions is Fermi catches a supernova,” he added. “It’s just that the chance of that is small. But if Fermi saw it, we’d be able to measure its mass. We’d be able to measure its interaction strength. We’d be able to determine everything we need to know about the axion and incredibly confident in the signal because there’s no ordinary matter which could create such an event.”
Astronomers have just found one of the youngest planets ever. At only 3 million years old, planet TIDYE-1b (also known as IRAS 04125+2902 b) is practically in its infancy. By comparison, Earth is 4.5 billion years old: that’s 1500 times older. The discovery of a planet this young can teach scientists a lot about the early stages of planet formation, and the peculiarities of this particular one have scientists re-evaluating their models of planetary birth.
“Astronomy helps us explore our place in the Universe — where we came from and where we might be going. Discovering planets like this one allows us to look back in time, catching a glimpse of planetary formation as it happens,” said Madyson Barber, lead author of a new paper and graduate student at UNC-Chapel Hill.
Barber discovered TIDYE-1b using the transit method, where a planet passes in front of its star, dimming the light and revealing itself to the observer – in this case, NASA’s TESS telescope. Previously, more than a dozen young planets in the 10-40 million-year-old range have been found via transit, but TIDYE-1b surpasses them all.
It’s a rare find because, under normal circumstances, such young planets are usually obscured by gas and dust that make up the ‘protoplanetary disc’, a debris field orbiting a star like a ring, out of which new planets are built.
“Planets typically form from a flat disk of dust and gas, which is why planets in our Solar System are aligned in a ‘pancake-flat’ arrangement,” explains Andrew Mann, associate professor at UNC-Chapel Hill. “But here, the disk is tilted, misaligned with both the planet and its star — a surprising twist that challenges our current understanding of how planets form.”
Since TIDYE-1b orbits its star at a different angle than the main protoplanetary disc, it was visible despite its youth. It can often take more than five million years for such a disc to clear out in a young star system, so this was a lucky break without which the astronomers would not have been able to see the planet.
The planet is very close to its star, orbiting around it about once every nine days. The researchers believe it is a young example of what will someday become a ‘super-Earth or a ‘sub-Neptune, a planet type missing in our solar system but which seems common in the wider Milky Way galaxy. TIDYE-1b is not as dense as the Earth is, but it is about 11 times larger in diameter.
The discovery provides conclusive evidence that planets can form earlier than previously known – the lack of examples of planets younger than 10 million years found so far is not because they don’t exist. It’s just because they tend to be hidden from view.
Earth and Mars were very similar in their youth. Four billion years ago, both planets had vast, warm seas. But while Earth retained its oceans, the waters of Mars evaporated away or froze beneath its dusty surface. Exactly why these two worlds took such divergent paths is unclear, though it may lie in the origins of their water.
Based on geological studies, we know that Earth’s water cycle seemed to have stabilized early. From about 4.5 billion years ago to today, water has had a stable presence on Earth. For Mars, things are less clear. Clay minerals cover about 45% of the Martian surface and date to what is known as the Noachian period, which ranges from 4.1 to 3.7 billion years ago. We also see evidence of water flows from 3.7 to 3.0 billion years ago, in what’s known as the Hesperian period. During the Amazonian period, which dates from 3 billion years ago to today, Mars seems to have been mostly dry. We have little evidence of the earliest period of Mars, known as the pre-Noachian. But a new study peels back the Martian ages to give us a glimpse of the first epoch of Mars, and it comes from a Martian meteorite known as Black Beauty.
Black Beauty, or NWA 7034, is a Martian meteorite thought to have formed at a time when the Red Planet harbored a magnetic field. Credit: C Agee, Institute of Meteoritics, UNM; NASA
There are about 200 meteorites known to have come from Mars, and they are currently the only physical samples of Mars we have on Earth. One of the larger meteorites, Northwest Africa 7034, was discovered in Western Sahara in 2011 and is nicknamed “Black Beauty” because of its rich black coloring. It’s made of material that’s about 4.4 billion years old and contains more water than any other Martian meteorite. But since it was only ejected from Mars 1.5 billion years ago, it is difficult to determine whether Black Beauty formed in a wet environment or if it gained water during the Noachian or Hesperian period.
This new study doesn’t focus on Black Beauty as a whole, but rather on small crystals of zircon embedded within it. These crystals can be dated to 4.48–4.43 billion years, meaning they formed in the Pre-Noachian period. What’s interesting is that the crystals have layers of iron, aluminum, and sodium in a pattern known as oscillatory zoning. Since zircon is igneous in origin, this kind of banding is almost unheard of in zircon crystals. On Earth, there is only one place where such a pattern occurs, which is in hydrothermal geysers such as those found in Yellowstone National Park.
The presence of these crystals in Black Beauty proves not only that Mars was wet during the Pre-Noachian period, but that it was geologically active with warm thermal vents. Similar vents on Earth may have triggered the formation of life on our world. Whether life ever existed on Mars is still an unanswered question, but it is clear that the conditions for life on Mars did exist in its earliest history.
Dark matter made out of axions may have the power to make space-time ring like a bell, but only if it is able to steal energy from black holes, according to new research.
An intriguing possibility for a candidate for the mysterious dark matter is that it might be an axion. Originally predicted to exist decades ago to explain some strange properties of the strong nuclear force, axions have yet to be detected in the laboratory or in any experiments. However, this elusiveness would make them a perfect candidate for dark matter, since by definition dark matter hardly if ever interacts with normal matter.
If the dark matter is an axion, or of a kind of particle related to the axion, then it would have very strange properties. It would be the lightest particle ever known, in some models no bigger than a billionth the mass of the electron. The incredible lightweight nature of this particle means that it would behave in very strange ways in the cosmos. It would be so light that its quantum wave nature would manifest on very large scales, meaning that it would tend to act more like a wave than a particle.
One of the ways this wave nature would manifest would be around rotating black holes. Through a process known as super-radiance, this kind of dark matter could steal angular momentum from the black hole. This would prevent the dark matter from falling through the event horizon, and instead it would pile up around the black hole like an invisible shroud.
But once no more new energy could be extracted from the black hole, the dark matter would evaporate away. In the process, according to new research, the dark matter would ring space-time like a bell, sending out an enormous amount of gravitational waves.
These gravitational waves would have a distinct signature from the ones known through black hole mergers. And even though they would be far weaker, they would be in the frequency ranges of detectability for existing and planned gravitational wave observatories.
The researchers proposed that we comb through existing data to hunt for any potential signatures of this kind of dark matter collecting around black holes. And if we don’t find what we looking for, we could still fine-tune upcoming experiments to hunt for this surprising signal.
