It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, December 16, 2021
WATCH — Is Marvel’s multiverse a real thing?
Story by Arjun Ram and CBC Kids News • December 14
Spider-Man: No Way Home uses the concept to revive old villains
Every week, CBC Kids News takes a deep dive into a topic that everyone’s talking about.
When Marvel Studios’ Spider-Man: No Way Home swings into theatres this month, it’ll prominently feature something called the multiverse.
What’s the multiverse? It’s basically the idea of alternate worlds, co-existing with our own.
In the new movie, which opens in theatres on Dec. 17, the concept is used to bring back villains from past Spider-Man films, and not just the recent ones starring Tom Holland.
The multiverse is reviving bad guys from another era of Spidey films, like Dr. Octopus and Green Goblin.
And while fans seem excited by Marvel’s multiverse, this isn’t the first time it’s popped up in movies, shows, or even comics.
So, where did the idea of a multiverse come from? And, superhero movies aside, is the multiverse a real thing?
There’s a lot to unbox here. But don’t worry, we’ve got you. KN Explains:
About the Contributor Arjun Ram CBC Kids News Contributor Arjun Ram is a Grade 10 French immersion student from Hamilton, Ont., with many diverse interests such as sports, music and math. Arjun has developed an interest in reporting on social and political issues as well as important developments in the area of professional sports. He hopes to one day work as a news anchor for CBC.
How real is the multiverse?
Is there another you out there, reading this exact same article? It's tough to say.
An artist's illustration of the multiverse. (Image credit: Shutterstock)
Imagine setting off in a rocket and leaving Earth. Leaving the solar system. Leaving our galaxy. Breaking through the edge of the observable universe and leaving our cosmos behind (which would be impossible, as you'd have to go faster than the speed of light, but work with me here).
Now you are cruising through the unfathomable void for eons, only to come upon another universe, with another galaxy inside it, with another solar system, another Earth … and another you, sitting there, reading this article.
This is the multiverse, and it might be a natural prediction of the physical theories that define the beginning of the universe. Or it might not. It's tough to say, as new research has shown.
Cosmologists largely believe that when our universe was extremely young — less than a trillionth of a trillionth of a second old — it went absolutely nuts. In the tiniest fraction of a moment of time (again, involving trillionths upon trillionths of a second), the universe got really, really big.
How big? It's hard to say exactly, because this concept is highly hypothetical, but "way bigger than you might think" should suffice. Most models of this event, called inflation, call for a universe that is at least 10^52 times bigger than the observable volume of the cosmos. Since that observable patch is already 90 billion light-years across, that means that the true extent of our universe is so big, it's nearly incomprehensible.
Inflation solves a lot of problems in standard Big Bang cosmology — a model that describes how the universe began — like the fact that regions of the universe vastly distant from each other have roughly the same temperature. According to inflation theory, those regions were once much cozier and got to know each other pretty well, before inflation ripped them apart.
There's another potential consequence of inflation: It may not be done. Indeed, it may never be done. This is called "eternal inflation," and this idea describes how the universe at the grandest scales may always be inflating, with only tiny pockets pinching off to become normal, sedate patches like our own. Each pinched-off island universe would be separated by a vast gulf of nothingness, with the islands flying away from each other faster than light (because that's what inflation does).
These island universes, embedded within the larger "multiverse," would never meet and could never talk to each other. In fact, it would be impossible to find direct evidence of their existence.
To inflate or not to inflate
Without that direct evidence, could we at least make an educated guess as to whether the multiverse is likely or not? If we're just one bubble in a giant bathtub filled with foam expanding faster than light, how could we figure this out?
The first step is to test inflation. The jury is still out on that, but there is some evidence that something like inflation happened in the early universe. The fluctuations in the cosmic microwave background, or the light released when our universe began to cool when it was 380,000 years old, have a pattern that matches what you'd see if inflation had occurred. No other theory of the early universe matches that pattern of light.
So that's good. But "inflation" isn't a single theory. It's more like a class or category of theories. Different models assume different physics, different drivers, different causes and different effects of this event. As all of these theories are based on hypothetical models of the extreme physics of the early universe, it's too early to tell which of the theories — if any — are correct.
Physicists suspect that eternal inflation is generic, meaning a consequence of most, if not all, models of inflation. So, following this suspicion, if inflation is correct, then eternal inflation is also likely correct, and the multiverse might be real. Judging the multiverse
Needless to say, the existence of the multiverse is a pretty big pill to swallow. If eternal inflation is correct, then there isn't just one universe, or a lot of universes, but an infinite number of pocket universes. Each one would potentially support its own laws of physics and arrangements of particles. So if the number of ways to arrange matter and energy is finite — there are only so many ways you can construct a universe — then an infinite multiverse demands repeated copies of the same physical situation, even if any particular combination of physical configurations is incredibly rare.
That means there's a copy of you, at some finite (but very far) distance away. And another copy past that. And another. And another. An infinity of you's doing this exact same thing.
But we can only say the multiverse is likely if eternal inflation is indeed generic (that is, a common feature of most, if not all, inflation models), which is exactly what a team of physicists claims in a recent paper, published to the preprint database arXiv and submitted to the Journal of Cosmology and Astroparticle Physics. They put a large number of inflation models through a grinder, varying the types of models and the model parameters, counting which ones were a one-and-done affair and which ones led to eternal inflation and a multiverse. Their answer: It's complicated.
First off, they found that eternal inflation wasn't nearly as common as originally thought. Their explanation for why cosmologists had thought eternal inflation was generic was because those earlier cosmologists had studied only a limited set of models. They found that many viable inflation models ("viable" here means they didn't obviously contradict observations) didn't lead to an eternally inflating scenario.
However, the researchers found that it's tough to even get a handle on measuring the "commonality" of something like eternal inflation, since we don't have a good grasp of inflation models and how they work. They argued that it's impossible to answer the question of genericness with a single answer, because there's so much we have yet to learn about the physics of inflation.
So is there another you out there, reading this exact same article? Science says: It's tough to say. Originally published on Live Science.
Paul Sutter Astrophysicist Paul M. Sutter is a research professor in astrophysics at SUNY Stony Brook University and the Flatiron Institute in New York City. He regularly appears on TV and podcasts, including "Ask a Spaceman." He is the author of two books, "Your Place in the Universe" and "How to Die in Space," and is a regular contributor to Space.com, Live Science, and more. Paul received his PhD in Physics from the University of Illinois at Urbana-Champaign in 2011, and spent three years at the Paris Institute of Astrophysics, followed by a research fellowship in Trieste, Italy.
Quantum physics requires imaginary numbers to explain reality
Theories based only on real numbers fail to explain the results of two new experiments To explain the real world, imaginary numbers are necessary, according to a quantum experiment (shown) performed by a team of physicists including Yali Mao (pictured) of the Southern University of Science and Technology in Shenzhen, China. JINGYUN FAN
Imaginary numbers might seem like unicorns and goblins — interesting but irrelevant to reality.
But for describing matter at its roots, imaginary numbers turn out to be essential. They seem to be woven into the fabric of quantum mechanics, the math describing the realm of molecules, atoms and subatomic particles. A theory obeying the rules of quantum physics needs imaginary numbers to describe the real world, two new experiments suggest.
Imaginary numbers result from taking the square root of a negative number. They often pop up in equations as a mathematical tool to make calculations easier. But everything we can actually measure about the world is described by real numbers, the normal, nonimaginary figures we’re used to (SN: 5/8/18). That’s true in quantum physics too. Although imaginary numbers appear in the inner workings of the theory, all possible measurements generate real numbers.
Quantum theory’s prominent use of complex numbers — sums of imaginary and real numbers — was disconcerting to its founders, including physicist Erwin Schrödinger. “From the early days of quantum theory, complex numbers were treated more as a mathematical convenience than a fundamental building block,” says physicist Jingyun Fan of the Southern University of Science and Technology in Shenzhen, China.
Some physicists have attempted to build quantum theory using real numbers only, avoiding the imaginary realm with versions called “real quantum mechanics.” But without an experimental test of such theories, the question remained whether imaginary numbers were truly necessary in quantum physics, or just a useful computational tool.
A type of experiment known as a Bell test resolved a different quantum quandary, proving that quantum mechanics really requires strange quantum linkages between particles called entanglement (SN: 8/28/15). “We started thinking about whether an experiment of this sort could also refute real quantum mechanics,” says theoretical physicist Miguel Navascués of the Institute for Quantum Optics and Quantum Information Vienna. He and colleagues laid out a plan for an experiment in a paper posted online at arXiv.org in January 2021 and published December 15 in Nature.
In this plan, researchers would send pairs of entangled particles from two different sources to three different people, named according to conventional physics lingo as Alice, Bob and Charlie. Alice receives one particle, and can measure it using various settings that she chooses. Charlie does the same. Bob receives two particles and performs a special type of measurement to entangle the particles that Alice and Charlie receive. A real quantum theory, with no imaginary numbers, would predict different results than standard quantum physics, allowing the experiment to distinguish which one is correct.
Fan and colleagues performed such an experiment using photons, or particles of light, they report in a paper to be published in Physical Review Letters. By studying how Alice, Charlie and Bob’s results compare across many measurements, Fan, Navascués and colleagues show that the data could be described only by a quantum theory with complex numbers.
Another team of physicists conducted an experiment based on the same concept using a quantum computer made with superconductors, materials which conduct electricity without resistance. Those researchers, too, found that quantum physics requires complex numbers, they report in another paper to be published in Physical Review Letters. “We are curious about why complex numbers are necessary and play a fundamental role in quantum mechanics,” says quantum physicist Chao-Yang Lu of the University of Science and Technology of China in Hefei, a coauthor of the study.
But the results don’t rule out all theories that eschew imaginary numbers, notes theoretical physicist Jerry Finkelstein of Lawrence Berkeley National Laboratory in California, who was not involved with the new studies. The study eliminated certain theories based on real numbers, namely those that still follow the conventions of quantum mechanics. It’s still possible to explain the results without imaginary numbers by using a theory that breaks standard quantum rules. But those theories run into other conceptual issues, making them “ugly,” he says. But “if you’re willing to put up with the ugliness, then you can have a real quantum theory.”
Despite the caveat, other physicists agree that the quandaries raised by the new findings are compelling. “I find it intriguing when you ask questions about why is quantum mechanics the way it is,” says physicist Krister Shalm of the National Institute of Standards and Technology in Boulder, Colo. Asking whether quantum theory could be simpler or if it contains anything unnecessary, “these are very interesting and thought-provoking questions.”
About Emily Conover Physics writer Emily Conover has a Ph.D. in physics from the University of Chicago. She is a two-time winner of the D.C. Science Writers’ Association Newsbrief award.
Artistic illustration of the study published in Nature. Credit: Georgy Ermakov and Sergey Lebedyanskiy.
Physicists construct theories to describe nature. Let us explain it through an analogy with something that we can do in our everyday life, like going on a hike in the mountains. To avoid getting lost, we generally use a map. The map is a representation of the mountain, with its houses, rivers, paths, etc. By using it, it is rather easy to find our way to the top of the mountain. But the map is not the mountain. The map constitutes the theory we use to represent the mountain's reality.
Physical theories are expressed in terms of mathematical objects, such as equations, integrals or derivatives. During history, physics theories evolved, making use of more elaborate mathematical concepts to describe more complicated physics phenomena. Introduced in the early 20th century to represent the microscopic world, the advent of quantum theory was a game changer. Among the many drastic changes it brought, it was the first theory phrased in terms of complex numbers.
Invented by mathematicians centuries ago, complex numbers are made of a real and imaginary part. It was Descartes, the famous philosopher considered as the father of rational sciences, who coined the term "imaginary," to strongly contrast it with what he called "real" numbers. Despite their fundamental role in mathematics, complex numbers were not expected to have a similar role in physics because of this imaginary part. And in fact, before quantum theory, Newton's mechanics or Maxwell's electromagnetism used real numbers to describe, say, how objects move, as well as how electro-magnetic fields propagate. The theories sometimes employ complex numbers to simplify some calculations, but their axioms only make use of real numbers.
Schrödinger's bewilderment
Quantum theory radically challenged this state of affairs because its building postulates were phrased in terms of complex numbers. The new theory, even if very useful for predicting the results of experiments, and for instance perfectly explains the hydrogen atom energy levels, went against the intuition in favor of real numbers. Looking for a description of electrons, Schrödinger was the first to introduce complex numbers in quantum theory through his famous equation. However, he could not conceive that complex numbers could actually be necessary in physics at that fundamental level. It was as though he had found a map to represent the mountains but this map was actually made out of abstract and non-intuitive drawings. Such was his bewilderment that he wrote a letter to Lorentz on June 6, 1926, stating "What is unpleasant here, and indeed directly to be objected to, is the use of complex numbers. Ψ is surely fundamentally a real function." Several decades later, in 1960, Prof. E.C.G. Stueckelberg, from the University of Geneva, demonstrated that all predictions of quantum theory for single-particle experiments could equally be derived using only real numbers. Since then, the consensus was that complex numbers in quantum theory were only a convenient tool.
However, in a recent study published in Nature, ICFO researchers Marc-Olivier Renou and ICREA Prof. at ICFO Antonio Acín, in collaboration with Prof. Nicolas Gisin from the University of Geneva and the Schaffhausen Institute of Technology, Armin Tavakoli from the Vienna University of Technology, and David Trillo, Mirjam Weilenmann, and Thinh P. Le, led by Prof. Miguel Navascués, from the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences in Vienna have proven that if the quantum postulates were phrased in terms of real numbers, instead of complex, then some predictions about quantum networks would necessarily differ. Indeed, the team of researchers came up with a concrete experimental proposal involving three parties connected by two sources of particles where the prediction by standard complex quantum theory cannot be expressed by its real counterpart.
Two sources and three nodes
To do this, they thought of a specific scenario that involves two independent sources (S and R), placed between three measurement nodes (A, B and C) in an elementary quantum network. The source S emits two particles, say photons, one to A, and the second to B. The two photons are prepared in an entangled state, say in polarization. That is, they have correlated polarization in a way which is allowed by (both complex and real) quantum theory but impossible classically. The source R does exactly the same, emits two other photons prepared in an entangled state and sends them to B and to C, respectively. The key point in this study was to find the appropriate way to measure these four photons in the nodes A, B, C in order to obtain predictions which cannot be explained when quantum theory is restricted to real numbers.
As ICFO researcher Marc-Olivier Renou comments "When we found this result, the challenge was to see if our thought experiment could be done with current technologies. After discussing with colleagues from Shenzhen-China, we found a way to adapt our protocol to make it feasible with their state-of-the-art devices. And, as expected, the experimental results match the predictions." This remarkable experiment, realized in collaboration with Zheng-Da Li, Ya-Li Mao, Hu Chen, Lixin Feng, Sheng-Jun Yang, Jingyun Fan from the Southern University of Science and Technology, and Zizhu Wang from the University of Electronic Science and Technology is published at the same time as the Nature paper in Physical Review Letters.
The results published in Nature can be seen as a generalization of Bell's theorem, which provides a quantum experiment which cannot be explained by any local physics formalism. Bell's experiment involves one quantum source S that emits two entangled photons, one to A, and the second to B, prepared in an entangled state. Here, in contrast, one needs two independent sources, the assumed independence is crucial and was carefully designed in the experiment.
The study also shows how outstanding predictions can be when combining the concept of a quantum network with Bell's ideas. For sure, the tools developed to obtain this first result are such that they will allow physicists to achieve a better understanding of quantum theory, and will one day trigger the realization and materialization of so far unfathomable applications for the quantum internet.Researchers investigate 'imaginary part' in quantum resource theory
Observing the stellar dance at the heart of the Milky Way has shown astronomers that 99.9 percent of the mass located there is possessed by the central black hole, named Sagittarius A* (Sgr A*), with just 0.1 percent attributed to stars, gas, and dust, dark matter and smaller black holes.
The team used cutting-edge astronomical equipment to measure the movement of four stars in the immediate vicinity of Sgr A*—S2, S29, S38, and S55—revealing details of the mass distribution at the center of the Milky Way.
The galactic center of the Milky Way, around 27,000 light-years from the solar system, contains a mass of at least 4.3 million times that of the sun, but until now astronomers have struggled to determine how much of this mass belonged to Sgr A*. That's because the galactic center is packed with a wealth of other cosmic objects and dense clouds of gas and dust.
"With the 2020 Nobel prize in physics awarded for the confirmation that Sgr A* is indeed a black hole, we now want to go further, We would like to understand whether there is anything else hidden at the center of the Milky Way and whether general relativity is indeed the correct theory of gravity in this extreme laboratory," Stefan Gillessen from the Max-Planck-Institute for Extraterrestrial Physics said. "The most straightforward way to answer that question is to closely follow the orbits of stars passing close to Sgr A*."
Gillessen is one of the authors of a paper set to publish in the journal Astronomy & Astrophysics detailing the team's work.
The researchers took advantage of a phenomenon predicted by Einstein's theory of general relativity, the most precise theory we have to describe gravity and therefore the orbits of moons, planets, and stars.
Video: Scientists Hurl Stars At Black Holes To See Who Survives In Incredible Simulation (Newsweek)
According to general relativity, orbits change their orientation over time tracing out a rosette-like pattern, a process called Schwarzschild precession. The astronomers traced out the rosette created by S2, S29, S38, and S55 by mapping their position and velocity.
To measure the velocities of the stars, the astronomers used spectroscopy from the Gemini Near-Infrared Spectrograph (GNIRS) at Gemini North near the summit of Maunakea in Hawai'i, and the SINFONI instrument on the European Southern Observatory's Very Large Telescope. The positions of the stars were measured with the GRAVITY instrument at the VLTI.
A diagram of stars dancing around the supermassive black hole at the heart of the Milky Way. GRAVITY collaboration/ESO
Detailing how these stars moved around Sgr A* and measuring the tiny variations in their orbits allowed the researchers to determine how mass was distributed in this region.
They found that mass within the orbit of the star S2 contributes only 0.1 percent of the total mass at the center of the Milky Way, leaving the other 99.9 percent owing to Sgr A*.
Measuring such tiny changes in the orbits of distant stars is no easy feat and a deeper investigation may have to wait until telescope technology improves.
"We will improve our sensitivity even further in future, allowing us to track even fainter objects," Gillessen concluded. "We hope to detect more than we see now, giving us a unique and unambiguous way to measure the rotation of the black hole."
An illustration showing stars close orbit around the supermassive black hole that dwells at the heart of the Milky Way, known as Sagittarius A* (Sgr A*). Astronomers have observed the dance of these stars in closer detail than ever before.
International Gemini Observatory/NOIRLab/NSF/AURA/J. da Silva/Spaceengine) Acknowledgement: M. Zamani (NSF's NOIRLab/NSF
Scientists say dark matter seems to be missing from the galaxy AGC 114905. Even after 40 hours of detailed measurements with state-of-the-art telescopes, they were unable to detect the presence of the elusive invisible matter that keep galaxies together. In this image, starlight is blue, and the green clouds are neutral hydrogen gas. Image via Javier Román/ Pavel Mancera Piña/ Royal Astronomical Society.
Dark matter is integral to modern cosmology, the science of our universe over time. Astronomers think that galaxies – the great star islands that are the building blocks of our universe – start to form due to accumulations of dark matter. So dark matter is thought to pervade our universe. That’s why, in 2019, after an international team of astronomers found six galaxies with no dark matter, colleagues told them to measure again and they’d find it. And measure they did. For example, they spent 40 hours examining galaxy AGC 114905 with the state-of-the-art Very Large Array observatory in New Mexico. But, still, there was no sign of dark matter. What does it mean? No one knows.
The team announced their confirmation of the dark-matter-free galaxy on December 6, 2021.
The researchers submitted their findings to the peer-reviewed journal Monthly Notices of the Royal Astronomical Society, which accepted it for publication on November 30, 2021. The preprint is available at arXiv.
A galaxy without dark matter
Galaxy AGC 114905 lies 250 million light-years away. Although it’s similar in size to our own Milky Way galaxy, AGC 114905 earns the classification of ultra-diffuse dwarf galaxy. This is because of how dim it is, with a thousand times fewer stars than our Milky Way galaxy.
When astronomers took their observations, made between July and October of 2020, and mapped them, they confirmed earlier observations. They plotted the rotational speed of the gas – how fast the gas moves around the center of the galaxy – at different distances from the center of the galaxy in a graph. This kind of graph is called a rotation curve. For nearly every galaxy measured in the universe, its rotation curve reveals a need for the presence of dark matter, matter that keeps the galaxy together even though its gas rotates “too fast” in the outer regions. But in AGC 114905, no dark matter is necessary to explain the motions of the gas.
Pavel Mancera Piña of University of Groningen and ASTRON, the Netherlands, said:
This is, of course, what we thought and hoped for because it confirms our previous measurements. But now the problem remains that the theory predicts that there must be dark matter in AGC 114905, but our observations say there isn’t. In fact, the difference between theory and observation is only getting bigger.
Paper co-author Pavel Mancera Piña. Image via Twitter.
Why doesn’t the galaxy have dark matter?
So why doesn’t AGC 114905 show any evidence of dark matter? One explanation could be that a large galaxy nearby stripped away the dark matter from the ultra-diffuse dwarf galaxy. Only there’s a problem with the nearby large galaxy theory, Piña explained:
There are none. And in the most reputed galaxy formation framework, the so called cold dark matter model, we would have to introduce extreme parameter values that are far beyond the usual range. Also with modified Newtonian dynamics, an alternative theory to cold dark matter, we cannot reproduce the motions of the gas within the galaxy.
The answer to the missing dark matter isn’t a nearby galaxy, and AGC 114905 doesn’t fit the two models that explain the formation of structures in the universe. There is one more possible explanation. If the angle at which they believe they are viewing the galaxy is not accurate, it could skew the results. Tom Oosterloo of University of Groningen and ASTRON, the Netherlands, said:
But that angle has to deviate very much from our estimate before there is room for dark matter again.
The team is going back to the original batch of six galaxies that showed no dark matter and are choosing another one to analyze. If it, too, continues to reveal no traces of dark matter, it will make their case even stronger.
Astronomers have previously discovered galaxies without hints of dark matter, though these objects remain rare anomalies.
Bottom line: Astronomers completed a 40-hour long observation of an ultra-diffuse dwarf galaxy and discovered no traces of dark matter.
This graphic depicts Perseverance's entry into "Séítah" from both an orbital and subsurface perspective. The lower image is a subsurface "radargram" from the rover's RIMFAX instrument; the red lines indicate link subsurface features to erosion-resistant rocky outcrops visible above the surface. Credit: NASA/JPL-Caltech/University of Arizona/USGS/FFI
Scientists with NASA's Perseverance Mars rover mission have discovered that the bedrock their six-wheeled explorer has been driving on since landing in February likely formed from red-hot magma. The discovery has implications for understanding and accurately dating critical events in the history of Jezero Crater—as well as the rest of the planet.
The team has also concluded that rocks in the crater have interacted with water multiple times over the eons and that some contain organic molecules.
These and other findings were presented today during a news briefing at the American Geophysical Union fall science meeting in New Orleans.
Even before Perseverance touched down on Mars, the mission's science team had wondered about the origin of the rocks in the area. Were they sedimentary—the compressed accumulation of mineral particles possibly carried to the location by an ancient river system? Or where they igneous, possibly born in lava flows rising to the surface from a now long-extinct Martian volcano?
"I was beginning to despair we would never find the answer," said Perseverance Project Scientist Ken Farley of Caltech in Pasadena. "But then our PIXL instrument got a good look at the abraded patch of a rock from the area nicknamed "South Séítah," and it all became clear: The crystals within the rock provided the smoking gun."
The drill at the end of Perseverance's robotic arm can abrade, or grind, rock surfaces to allow other instruments such as PIXL to study them. Short for Planetary Instrument for X-ray Lithochemistry, PIXL uses X-ray fluorescence to map the elemental composition of rocks. On Nov. 12, PIXL analyzed a South Séítah rock the science team had chosen to take a core sample from using the rover's drill. The PIXL data showed the rock, nicknamed "Brac," to be composed of an unusual abundance of large olivine crystals engulfed in pyroxene crystals.
"A good geology student will tell you that such a texture indicates the rock formed when crystals grew and settled in a slowly cooling magma—for example a thick lava flow, lava lake, or magma chamber," said Farley. "The rock was then altered by water several times, making it a treasure trove that will allow future scientists to date events in Jezero, better understand the period in which water was more common on its surface, and reveal the early history of the planet. Mars Sample Return is going to have great stuff to choose from."
The multi-mission Mars Sample Return campaign began with Perseverance, which is collecting Martian rock samples in search of ancient microscopic life. Of Perseverance's 43 sample tubes, six have been sealed to date—four with rock cores, one with Martian atmosphere, and one that contained "witness" material to observe any contamination the rover might have brought from Earth. Mars Sample Return seeks to bring select tubes back to Earth, where generations of scientists will be able to study them with powerful lab equipment far too large to send to Mars.
Still to be determined is whether the olivine-rich rock formed in a thick lava lake cooling on the surface or in a subterranean chamber that was later exposed by erosion.
Taken by Perseverance’s Mastcam-Z instrument, this video features an enhanced-color composite image that pans across Jezero Crater’s delta on Mars. The delta formed billions of years ago from sediment an ancient river carried to the mouth of a lake that once existed in the crater. Credit: NASA/JPL-Caltech/ASU/MSSS
Organic molecules
Also great news for Mars Sample Return is the discovery of organic compounds by the SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instrument. The carbon-containing molecules are not only in the interiors of abraded rocks SHERLOC analyzed, but in the dust on non-abraded rock.
Confirmation of organics is not a confirmation that life once existed in Jezero and left telltale signs (biosignatures). There are both biological and non-biological mechanisms that create organics.
"Curiosity also discovered organics at its landing site within Gale Crater," said Luther Beegle, SHERLOC principal investigator at NASA's Jet Propulsion Laboratory in Southern California. "What SHERLOC adds to the story is its capability to map the spatial distribution of organics inside rocks and relate those organics to minerals found there. This helps us understand the environment in which the organics formed. More analysis needs to be done to determine the method of production for the identified organics."
The preservation of organics inside ancient rocks—regardless of origin—at both Gale and Jezero Craters does mean that potential biosignatures (signs of life, whether past or present) could be preserved, too. "This is a question that may not be solved until the samples are returned to Earth, but the preservation of organics is very exciting. When these samples are returned to Earth, they will be a source of scientific inquiry and discovery for many years," Beegle said.
Six facsimile sample tubes hang on the sample tube board. Credit: NASA/JPL-Caltech
'Radargram'
Along with its rock-core sampling capabilities, Perseverance has brought the first ground-penetrating radar to the surface of Mars. RIMFAX (Radar Imager for Mars' Subsurface Experiment) creates a "radargram" of subsurface features up to about 33 feet (10 meters) deep. Data for this first released radargram was collected as the rover drove across a ridgeline from the "Crater Floor Fractured Rough" geologic unit into the Séítah geologic unit.
The ridgeline has multiple rock formations with a visible downward tilt. With RIMFAX data, Perseverance scientists now know that these angled rock layers continue at the same angle well below the surface. The radargram also shows the Séítah rock layers project below those of Crater Floor Fractured Rough. The results further confirm the science team's belief that the creation of Séítah preceded Crater Floor Fractured Rough. The ability to observe geologic features even below the surface adds a new dimension to the team's geologic mapping capabilities at Mars.Rocks on floor of Jezero Crater, Mars, show signs of sustained interactions with water
More information:For more about Perseverance: mars.nasa.gov/mars2020/ and nasa.gov/perseverance
Lava once flowed at the site of an ancient lake on Mars.
The Perseverance rover landed on the planet just 10 months ago, but it has already made that surprising discovery.
The rover's latest finding suggests that the bedrock it has been driving over since landing was once formed by volcanic lava flows -- something that was "completely unexpected," according to mission scientists. Previously, they thought the layered rocks Perseverance took photos of were sedimentary.
The rocks that Perseverance has sampled so far also revealed that they interacted with water multiple times, and some of them include organic molecules.
These discoveries could help scientists create an accurate timeline for the events that have taken place in Jezero Crater, the site of an ancient lake, and has wider implications for understanding Mars.
The finding was announced Wednesday during the American Geophysical Union Fall Meeting in New Orleans.
For years, scientists have questioned if the rock in this crater was sedimentary rock, comprised of layers of material deposited by an ancient river, or igneous rock, which forms when lava flows cool.
Perseverance took this photo of Jezero Crater in April. The flat-topped hill, named Kodiak, has ancient layered rocks.
"I was beginning to despair we would never find the answer," said Ken Farley, Perseverance project scientist at the California Institute of Technology in Pasadena, California, in a statement.
Everything changed when Perseverance began using a drill on the end of its robotic arm to scrape away at the surfaces of rocks.
"The crystals within the rock provided the smoking gun," Farley said.
Perseverance is armed with a suite of sophisticated instruments that can image and analyze these scraped rocks, revealing their composition and mineral content. Ones of these instruments is PIXL, or the Planetary Instrument for X-ray Lithochemistry.
In November, Perseverance used its instruments to study a rock, nicknamed "Brac" by the team. The analysis revealed large olivine crystals surrounded by pyroxene crystals, both of which pointed to the fact that the rock came from volcanic lava flows.
"A good geology student will tell you that such a texture indicates the rock formed when crystals grew and settled in a slowly cooling magma -- for example a thick lava flow, lava lake, or magma chamber," Farley said.
"The rock was then altered by water several times, making it a treasure trove that will allow future scientists to date events in Jezero, better understand the period in which water was more common on its surface, and reveal the early history of the planet. Mars Sample Return is going to have great stuff to choose from."
Now, the team wants to know if the rocks containing olivine were formed by a cooling lake of lava, or if they originated from a subsurface chamber of lava that was later exposed due to erosion.
"This was completely unexpected, and we are struggling to understand what it means," Farley said. "But I will speculate that this is not likely the original crater floor. From the diameter of this crater, we expect the original crater floor is significantly deeper than where we are right now."
It's possible that lava flowed down into the crater, he said, but the original crater floor is below the rock they are driving over now.
Bringing back samples
So far, Perseverance has collected four rock samples with plans to collect up to 37 more. These samples will be returned to Earth by future missions, which will enable them to be studied in great detail and a variety of ways. Samples from Jezero Crater and its river delta could reveal if life ever existed on Mars.
Once back on Earth, volcanic rocks can be dated with very high accuracy, so these latest samples could help the team establish more accurate dates for features and events on Mars.
These rocks interacted with water over time to create new minerals. The minerals within the samples can reveal what the climate and environment was like and even the composition of the water billions of years ago on the red planet.
"That will tell us whether or not the water that existed there was potentially habitable in the past," said Kelsey Moore, geobiologist and postdoctoral scholar research associate in planetary science at the California Institute of Technology.
The rover also detected organic molecules in the rock it sampled, using its SHERLOC instrument, or Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals.
The presence of organic molecules doesn't necessarily equal signs of past life, or biosignatures. Organics can be created biologically or abiotically -- a physical process that does not include living organisms.
The Curiosity rover, which landed on Mars in 2012, has also discovered organics within its landing site of Gale Crater. Now that Perseverance has detected them, too, "this helps us understand the environment in which the organics formed," said Luther Beegle, SHERLOC principal investigator at NASA's Jet Propulsion Laboratory in Pasadena, in a statement.
While more investigation is needed to determine how these organic molecules were created, their presence gives the science team hope. That's because it means that signs of past or present life could be preserved on Mars as well, if life ever existed there.
"When these samples are returned to Earth, they will be a source of scientific inquiry and discovery for many years," Beegle said.
And Perseverance has also been using its onboard ground-penetrating radar instrument, the first ever to be tested out on Mars. The Radar Imager for Mars' Subsurface Experiment, or RMFAX, was used to "to peek into the subsurface and determine the structure of a rock under our wheels," said Briony Horgan, associate professor of planetary science at Purdue University and a scientist on the rover mission.
The experiment was used as the rover drove across a ridgeline. The radar data revealed multiple rock formation with a downward tilt, which continue below the surface from the ridgeline itself. Instruments like RIMFAX can help scientists create a better geologic map of Mars to understand its history.
Investigating an ancient river
Perseverance had a banner year in 2021 and it will move on to even more intriguing territory next year: the ancient river delta.
This fan-shaped structure has intrigued scientists for years, and Farley said the rover will arrive at the delta in about six or eight months.
The rocks in the delta are most likely sedimentary, trapping and preserving precious layers of silt from the river that once flowed into the crater's lake. And the samples could reveal if organic molecules associated with signs of life, or even microfossils, could be hiding within the remains of the delta.
Astronomers Detect Secret Water Reserves in The Largest Canyon in The Solar System
A vast system of canyons that dramatically scars the face of Mars could be harboring reserves of hidden water.
An unusually high quantity of hydrogen has been detected in the heart of the 4,000 kilometers (2,485 miles) of canyons known as Valles Marineris, nicknamed the Grand Canyon of Mars. We know this thanks to new data from the ESA-Roscosmos ExoMars Trace Gas Orbiter's FREND instrument.
The finding suggests that, at depths up to a meter (three feet) below the surface, the soil in the region is rich in water, either bound up in minerals or as subsurface water ice, potentially offering a new way of locating the precious stuff on the apparently extremely arid world.
"With the Trace Gas Orbiter, we can look down to one meter below this dusty layer and see what's really going on below Mars's surface – and, crucially, locate water-rich 'oases' that couldn't be detected with previous instruments," said physicist Igor Mitrofanov of the Space Research Institute of the Russian Academy of Sciences in Russia; lead author of the new study.
"FREND revealed an area with an unusually large amount of hydrogen in the colossal Valles Marineris canyon system: Assuming the hydrogen we see is bound into water molecules, as much as 40 percent of the near-surface material in this region appears to be water."
We know there's water on Mars. We can see it, at the cold poles, bound up as ice. That's where most of it seems to be; at the equator, conditions are too warm for water ice to form at the surface.
It's possible that water can be found under the surface, but other previous searches by other Mars satellites only found it at higher latitudes.
Cue FREND, or the Fine Resolution Epithermal Neutron Detector. Rather than mapping light at the very surface of the red planet, FREND detects neutrons. This allows it to see the hydrogen content of Mars's soil up to a meter below the surface, the researchers said. Which, in observations taken between May 2018 and February 2021, it seems to have done.
"Neutrons are produced when highly energetic particles known as galactic cosmic rays strike Mars; drier soils emit more neutrons than wetter ones, and so we can deduce how much water is in a soil by looking at the neutrons it emits," said physicist Alexey Malakhov, also of the Space Research Institute of the Russian Academy of Sciences.
"We found a central part of Valles Marineris to be packed full of water – far more water than we expected. This is very much like Earth's permafrost regions, where water ice permanently persists under dry soil because of the constant low temperatures."
Viking orbiter mosaic showing Valles Marineris across the face of Mars. (NASA)
The high-hydrogen region is about the size of the Netherlands, and overlaps with Candor Chasma, one of the largest canyons in the Valles Marineris system. In this region of Mars, minerals typically contain very little water, so the researchers believe the substance is likely in the form of water ice below the surface.
But how that water could persist there is a mystery. Pressure and temperature conditions at the Mars equator ought to prohibit the formation of such water reserves. There may be some unknown combination of geomorphological conditions in Valles Marineris that allows it, such as patchy isolated deposits that have been there for some time, or the angle and orientation of steep slopes.
Further investigation will be needed to work out exactly what is going on – not just the conditions that allow for equatorial water on Mars, but to confirm what form that water takes. Doing so could be deeply rewarding: stores of water in a permafrost-like form may, just as we have found right here on Earth, have preserved frozen fragments of microbial life, or organic molecules that once existed on Mars.
The discovery also represents exciting possibilities for Mars exploration. Any crewed Mars mission is likely to set down near the equator; water that might be found not far beneath the surface would be an amazing asset, both for exploration purposes, and for the vital task of keeping water-reliant humans alive.
"This result really demonstrates the success of the joint ESA-Roscosmos ExoMars programme," said physicist Colin Wilson of the European Space Agency.
"Knowing more about how and where water exists on present-day Mars is essential to understand what happened to Mars's once-abundant water, and helps our search for habitable environments, possible signs of past life, and organic materials from Mars's earliest days."
A depiction of canyons (left), and Mars itself (right).1, 2
The Red Planet is hiding an appealing secret.
Scientists have discovered a world-historic discovery on Mars: "significant amounts of water" are hiding inside the Red Planet's Valles Marineris, its version of our grand canyon system, according to a recent press release from the European Space Agency (ESA).
And up to 40% of material near the surface of the canyon could be water molecules.
Mars' Valles Marineris canyon system is hiding water
The newly discovered volume of water is hiding under the surface of Mars, and was detected by the Trace Gas Orbiter, a mission in its first stage under the guidance of the ESA-Roscosmos project dubbed ExoMars. Signs of water were picked up by the orbiter's Fine Resolution Epithermal Neutron Detector (FREND) instrument, which is designed to survey the Red Planet's landscape and map the presence and concentration of hydrogen hiding in Mars' soil. It works like this: while high-energy cosmic rays plunge into the surface, the soil emits neutrons. And wet soil emits fewer neutrons than dry soil, which enables scientists to analyze and assess the water content of soil, hidden beneath its ancient surface. "FREND revealed an area with an unusually large amount of hydrogen in the colossal Valles Marineris canyon system: assuming the hydrogen we see is bound into water molecules, as much as 40% of the near-surface material in this region appears to be water," said Igor Mitrofanov, the Russian Academy of Science's lead investigator of the Space Research Institute, in the ESA press release.
Scientists have already discovered water on Mars, but most earlier discoveries detected the substance crucial to life as we know it near the poles of the Red Planet, subsisting as ice. Only very small pockets of water had shown up at lower latitudes, which was a big downer because future astronauts on Mars will need a lot of water, and there are better prospects for settling the planet at lower latitudes. But now, with what seems like a comparative abundance of water in Valles Marineris, we've taken a major step toward establishing a reliable source of water on the closest alien world.
Mars' canyon water could be liquid, ice, or a messy mix
"The reservoir is large, not too deep below ground, & could be easily exploitable for future explorers," read a tweet on the announcement from ExoMars. That sounds basically great! But it's too soon for Musk to pack up his bags and fly to the site, since much work is left to be done. A study accompanying the announcement, published in the journal Icarus, shows that neutron detection doesn't distinguish between ice and water molecules. This means geochemists need to enter the scientific fray to reveal more details. But several features of the canyon, including its topology, have led the researchers to speculate that the water is probably in solid form (ice). But it could also be a mixture of solid and liquid.
"We found a central part of Valles Marineris to be packed full of water — far more water than we expected," said Alexey Malakhov, co-author of the study, in the ESA release. "This is very much like Earth's permafrost regions, where water ice permanently persists under dry soil because of the constant low temperatures." So while we don't yet know the specific form of water is lying under Mars' vast system of canyons, the first human mission to Mars may consider exploring this area a major priority.
This was a breaking story and was regularly updated as new information became available.
