When it comes to the worlds beyond Earth in our Solar System, it’s only natural to wonder whether our planet was alone in being home to native life. The fourth planet from the Sun, Mars, is a particularly interesting candidate, as there’s overwhelming evidence that its surface once possessed large amounts of liquid water, pooling in lakes, rivers, and even oceans. Long ago, we have every reason to suspect it had a thick atmosphere, temperate conditions, and even a third, inner, massive moon that dwarfed the other two — Phobos and Deimos — before falling back to Mars.
While Mars itself is vast, and any life that was once present has likely been extinct for billions of years, there’s a simple place to go to look for evidence of ancient processes that are easy to access: its innermost moon, Phobos. If we could gather material from the Phobian regiolith and bring it back here to Earth, we could analyze it and either confirm or challenge our best-supported ideas for the geological and chemical history of the red planet, and perhaps even find evidence for ancient life there. This isn’t a pipe dream, nor is it science fiction, but an actual mission approved and planned for launch in 2024: Martian Moons eXploration (MMX).
Upon its return to Earth in July of 2029, we’ll be able to analyze its samples, determining whether Mars was once home to life, whether Phobos was the result of a Martian impact or asteroid capture, and either confirming or rejecting a whole slew of hypotheses concerning Mars’s history. Here’s what we all should know.
The relative sizes of the asteroid-like moons of Mars, Phobos and Deimos. Phobos is the innermost … [+] moon of Mars while the smaller Deimos is more than twice as far away. Despite their appearances as looking similar to asteroids, it’s thought that Phobos and Deimos were once joined by a larger, third, inner moon, which has since decayed and fallen back to Mars. All are thought to originate from a giant, ancient impact.
NASA/JPL-Caltech
If we rewind the clock all the way back to the first ~1 billion years of the Solar System, the inner planets likely would have looked very different to the way they appear today, some 4.6 billion years after our formation. Earth, although life was already present in its oceans, had an atmosphere that was rich in molecules like methane and ammonia, with very small amounts of oxygen: produced as the waste product of anaerobic lifeforms. Venus and Mars, meanwhile, may have both been similarly hospitable to life early on, as they were anticipated to have atmospheres similar in thickness and composition to Earth’s, with copious amounts of liquid water on the surface and the same raw ingredients — precursor molecules to life — that were present in large quantities on Earth.
While Venus and Mars are suspected to have had divergent histories from both Earth and one another, their early environments may have been extremely similar to Earth’s. As such, they may have possessed simple lifeforms in their early days just as Earth did. If we can investigate them in sufficient detail, we just might find the critical evidence that reveals that life may not have been unique to Earth, even within our own Solar System. While it might make sense to probe the planets themselves for such evidence, the billions of years that have subsequently passed may make such signals difficult to unambiguously extract. That’s where the potential of Mars’s innermost moon, Phobos, comes into play.
A large impact from an asteroid billions of years ago may have created the moons of Mars, including … [+] an inner, larger one that no longer exists today. Subsequently, impacts from asteroids, centaurs, and comets should kick up debris that’s accumulated on the Martian moons, and should persist to the present day.
Illustration by Medialab, ESA 2001
The Solar System isn’t a well-siloed environment, where “what happens on a planet stays on that planet.” Instead, it’s an active, dynamical place, where asteroids, centaurs, and comets routinely cross the orbits of the planets and moons. While gravitational interactions frequently occur, perturbing orbits, causing energy exchange, and leading to the ejection or capture of various bodies, there’s also a non-trivial possibility of having a collision between one of these fast-moving, low-mass bodies and a planet or moon. When such an impact event occurs, it not only creates a crater on the world and covers it in debris, but can also kick fragments of the world it impacts out into space.
Every rocky planet and moon in the Solar System that we’ve investigated up close and doesn’t rapidly refresh its surface — either through volcanic activity, like Jupiter’s moon Io, or through the turnover of ices and liquids, like Saturn’s Enceladus or Neptune’s Triton — shows copious evidence for both recent and ancient cratering. Mercury, Mars, the Moon, and Ganymede are covered in a rich array of craters of varying ages, and it’s known that these impacts can send debris from one region of the Solar System to elsewhere: in that planet’s orbit and beyond. In fact, of all the meteorites that have been recovered here on Earth, approximately 3% of them have been determined to be of Martian origin.
Structures on ALH84001 meteorite, which has a Martian origin. Some argue that the structures shown … [+] here may be ancient Martian life, while others argue that these are abiotic inclusions. At present, we do not have sufficient and unambiguous evidence to indicate the history of life on Mars, but future experiments and missions may yet reveal an answer to that question.
NASA, from 1996
If impacts on Mars can routinely send Martian debris all the way to planet Earth, it would be an absurdity for the particulate debris from those impacts to not extend above the Martian atmosphere, where it would collide with and stick to the Martian moons: Phobos and Deimos. Throughout the history of Mars, collisions with Mars-crossing asteroids and comets should have produced copious amounts of impact events, delivering a substantial fraction of the ejected material to its moons. Being closer to Mars than outermost Deimos, Phobos is expected to have accrued more than 1 million tons of Martian material, now mixed into its regiolith.
Based on numerical simulations, the fraction of Martian material mixed into Phobos’s outermost layers should exceed ~1-part-in-1000, making this an excellent place to look for “dead biosignatures” of Martian origin. The researchers searching for such extinct clues to past life on Mars have named it SHIGAI, for Sterilized and Harshly Irradiated Genes and Ancient Imprints, which also means “dead remains” in Japanese. Despite the harsh environment of space and exposure to billions of years of solar wind and radiation, these remains should persist. By sampling and returning the cocktail of material collected from Phobos’s regiolith, scientists will be able to analyze material originating from different eras and different locations across the surface of Mars.
Mars, along with its thin atmosphere, as photographed from the Viking orbiter. As you can clearly … [+] see with even a visual inspection, Mars is heavily cratered all over its surface, with some craters exhibiting smaller craters within them. This is a typical feature of a very old planetary surface which has endured for billions of years. The debris from these impacts likely accumulates on the Martian moons: Phobos and Deimos.
NASA / Viking 1
The MMX mission, developed by the Japanese Aerospace Exploration Agency (JAXA), has already been in the planning and development stages since its announcement in 2015. The plan is for it to softly land on Phobos at least once (and possibly twice, to get two different sample locations), to collect samples using a pneumatic system. Once a sufficiently large set of samples have been taken, it will take off once again, flying-by Deimos numerous times, observing it and Mars, and then sending the sample-containing Return Module back to Earth for analysis. The Return Module itself is expected to arrive on Earth in July of 2029.
If this sounds ambitious, that’s because it is. Only a very small set of missions have ever accomplished the joint feats of:
traveling from Earth to another body in the Solar System,
making a soft, controlled landing there,
collecting samples from the object it landed on,
successfully taking off once again,
completing the journey back to Earth,
and surviving atmospheric re-entry,
so that the collected samples can be recovered an analyzed.
JAXA has been the world leader in endeavors such as this, with the Hayabusa and Hayabusa2 missions successfully returning samples from asteroids Itokawa and Ryugu: the first two sample return missions to be conducted since NASA’s Apollo program. While material is expected to be returned from Mars to Earth via the Mars Sample Return mission, the MMX mission should return the material collected from Phobos even earlier, providing the first return of Martian material, including the remains of possible organics, to Earth.
The Mars Orbiter Laser Altimeter (MOLA) instrument, part of Mars Global Surveyor, collected over 200 … [+] million laser altimeter measurements in constructing this topographic map of Mars. The Tharsis region, at center-left, is the highest elevation region on the planet, while the lowlands appear in blue. Note the much lower elevation of the northern hemisphere compared to the southern, with a mean difference in elevation of around ~5 km.
Mars Global Surveyor MOLA team
Depending on what arrives upon MMX’s return to Earth, we could uncover a view of Phobos that aligns with our current theories about its formation and history. Alternatively, we could receive a tremendous set of surprises that, quite literally, rewrites what we know about the history of Mars and the Martian planetary system. For example, like the other rocky planets present in our Solar System, we fully anticipate that Mars was born without moons of any type. After surviving the earliest phases of planet-formation in our youth, a major impact was suspected to occur, kicking up a large amount of debris that coalesced into three moons: a large, massive, innermost moon, with much-smaller Phobos orbiting exterior to that and Deimos comprising the final, outermost satellite.
Eventually, owing to both tidal forces and atmospheric drag, the innermost moon was disrupted and fell back to Mars, where it very likely created the large, asymmetric basin that accounts for the severe differences between the two hemispheres of Mars, as well as kicking up a tremendous amount of debris that could land on both Phobos and Deimos. If the material returned to Earth from Phobos matches up extraordinarily well with the material we’ve sampled and analyzed on the Martian surface — as determined by orbiters, landers, and rovers — the MMX mission could serve as a spectacular confirmation of this picture, strongly supported by simulations and the current evidence at hand.
Rather than the two Moons we see today, a collision followed by a circumplanetary disk may have … [+] given rise to three moons of Mars, where only two survive today. This hypothetical transient moon of Mars, proposed in a 2016 paper, is now the leading idea in the formation of Mars’s moons.
LABEX UNIVEARTHS / UNIVERSITÉ PARIS DIDEROT
However, it’s possible that the full suite of evidence is conspiring, at present, to mislead us about the origins of Phobos and Deimos. Perhaps there wasn’t a large, ancient impact on Mars that led to the origins of its moons; perhaps, instead, Phobos and Deimos are more like Saturn’s “oddball” moon Phoebe: a captured object, such as an asteroid, originating from elsewhere in the Solar System. While the orbits of Phobos and Deimos are extremely consistent with an origin from an ancient impact, their compositions and appearances appear to be quite asteroid-like. A sample return mission would reveal whether the composition of Phobos matches that of Mars or of the known types of asteroids.
It’s also possible that, despite its watery past and life-friendly early conditions, that life may not have ever arisen on the red planet. The evidence we have strongly indicates that over the first ~1+ billion years of the Solar System’s history, Mars possessed a thick atmosphere with large amounts of liquid water, and then transitioned — likely because of the death of its core’s magnetic dynamo — to become a low-pressure world where liquid water on its surface was impossible. The chemical imprints of such a scenario should appear frozen-in to the regiolith of Phobos if it occurred; if not, Phobos might reveal an alternative history, even one that’s entirely unexpected.
Winds at speeds up to 100 km/hr travel across the martian surface. The craters in this image, caused … [+] by impacts in Mars’ past, all show different degrees of erosion. Some still have defined outer rims and clear features within them, while others are much smoother and featureless, almost seeming to run into one another or merge with their surroundings.
ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO
It might seem that sampling Mars, directly, is a far superior approach to sampling Phobos, but that’s not entirely true. As we can clearly see from orbiters, landers, and rovers, different locations on Mars have not only experienced substantially different histories, but leave different chemical fingerprints even today. The seasonal methane “burps” that we see coming from the ground don’t occur everywhere, but rather are limited in location and duration. Whenever we sample Mars directly and return its contents to Earth, we’re limited to whatever biomarkers — modern and ancient — are present at that specific location. If there’s life on Mars, but simply not in the location we’re sampling, we’ll miss it.
On the other hand, because impacts on Mars have occurred all over its surface and all throughout its history, the material of Martian origin that’s been deposited on Phobos means that the Phobian environment should truly provide a random sample of Mars. All possible Martian materials, from sedimentary to igneous rocks, covering all of Mars’s geological areas, should be present in some sort of quantity on Phobos. At the very least, the regiolith of Phobos should have significant contributions from several different regions and epochs on Mars. By collecting material from it and returning to Earth, we should get a random sample that provides insight into the planet-wide history of biological and chemical remnants on Mars, shedding light on any ancient life that may have existed there at one point.
Seasonal changes, repeated over many years, have been detected in the geochemistry experiments of … [+] the Mars Curiosity Rover. Methane peaks in the summer and dips in the winter, but is always present at Curiosity’s location. However, methane is not present everywhere, indicating that whatever is creating it is at least somewhat localized.
NASA/JPL-Caltech
There’s one more point that makes a sample return mission to Phobos so exciting: the comparably low degree of difficulty when compared to a sample return mission from Mars. First off, just like asteroids Itokawa and Ryugu, Mars’s moon Phobos is low enough in mass that it’s certainly covered in loosely-held rock, rubble, and dust, meaning that the instruments should have little difficulty in collecting the necessary material for a sample return. Second, the lack of any atmosphere and the extremely low surface gravity of Phobos should make gravitational escape extremely easy, compared to the difficulty of returning a sample from a world like Mars. Comparatively, a full-scale launch and return from the Martian surface — something never before attempted — is an exciting but risky proposition.
And finally, this would be the third attempt at an uncrewed sample return mission from a small-mass, airless body. It’s being performed by the same agency, JAXA, that has made the only two previous attempts: Hayabusa and Hayabusa2, both of which were successful. Ideally, both a Mars Sample Return mission and MMX, bringing back material from Phobos, will both be successful. But if you had to bet on only one, MMX has far fewer obstacles, and far fewer incidences of engineering problems that have never been reckoned with before, than a direct-from-Mars sample return.
A Mars Sample Return mission, designed to rendezvous with the Perseverance rover and return the … [+] sample tubes it’s collected from within Jezero crater, could give humanity our first uncontaminated, direct-from-Mars materials to analyze. If there’s extant life on Mars, a Mars Sample Return mission will be the most expedient and surefire way to discover and characterize it.
NASA/JPL
It remains a fascinating and open question — perhaps the most interesting question we can ask about life beyond Earth in the Solar System — whether life ever existed on Mars. Although it’s a highly speculative proposition, it’s one that we have the potential to answer: not just down the road, but in the very near future. The combination of orbiters, landers, and rovers we have, both today and upcoming in the near-future mission timeline, will shed light on the presence and concentration of various biomarkers in the atmosphere, on Mars’s surface, and just beneath its surface. If the seasonal methane has a biological origin rather than a geochemical one, we should be able to know within a single decade.
When you fold in the upcoming sample return missions, from both Jezero Crater on Mars and from the surface of Phobos, we should become sensitive not only to the possibility of extant life on Mars, but of even ancient, now-extinct life. If life exists there now, these missions could teach us how such life first emerged and, later, evolved. If Mars was always devoid of life, these missions will provide valuable information in revealing why Mars is lifeless while Earth has always teemed with it. As always, the most important lesson is this: if we want to know what’s out there, the only way to find out is to look. With the Martian Moons eXplorer mission, the answers might be in our hands before the decade comes to a close.
More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.
That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.
“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”
The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.
Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.
Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.
Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.
Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.
Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.
“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”
The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.
North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.
Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”
Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.
Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.
For Dello, the “fingerprints of climate change” were clear.
“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”
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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.
On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.
They call it “Big Sam.”
The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.
It didn’t die alone.
“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.
She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”
“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.
The head alone, she said, is about the size of a baby elephant.
The discovery was a long time coming.
The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.
“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.
When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”
“It contains about 100 to 300 bones per square metre,” she said.
Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.
About a year ago, they found the second adult: Big Sam.
Bamforth said both dinosaurs are believed to have been the elders in the herd.
“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.
“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”
The genders of the two adults are unknown.
Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.
The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.
She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.
“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.
“It’s pretty exciting.”
This report by The Canadian Press was first published Sept. 25, 2024.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
