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Why some scientists believe life may have started on Mars – Salon

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On February 18, NASA’s Perseverance rover will parachute through thin Martian air, marking a new era in red planet exploration. Landing on the Jezero Crater, which is located north of the Martian equator, will be no easy feat. Only about 40 percent of the missions ever sent to Mars succeed, according to NASA. If it does, Perseverance could drastically change the way we think about extraterrestrial life. That’s because scientists believe Jezero, a 28 mile-wide impact crater that used to be a lake, is an ideal place to look for evidence of ancient microbial life on Mars.

Once it lands, Perseverance will collect and store Martian rock and soil samples, which will eventually be returned to Earth. This is known as a “sample-return mission,” an extremely rare type of space exploration mission due to its expense. (Indeed, there has never been a sample return mission from another planet.) And once Martian soil is returned to Earth in a decade, scientists will set about studying the material to figure out if there was ever ancient life on Mars. 

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Yet some scientists believe that these samples could answer an even bigger question: Did life on Earth originate on Mars?

Though the idea that life started on Mars before migrating on Earth sounds like some far-fetched sci-fi premise, many renowned scientists take the theory seriously. The general idea of life starting elsewhere in space before migrating here has a name, too: Panspermia. It’s the hypothesis that life exists elsewhere in the universe, and is distributed by asteroids and other space debris.

To be clear, the notion of life on Earth originating on Mars isn’t a dominant theory in the scientific community, but it does appear to be catching on. And scientists like Gary Ruvkun, a professor of genetics at Harvard Medical School, say that it does sound “obvious, in a way.”

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The evidence starts with how space debris moved around in the young solar system. Indeed, we have evidence of an exchange of rocks from Mars to Earth. Martian meteorites have been found in Antarctica and across the world — an estimated 159, according to the International Meteorite Collectors Association.

“You can assign them to Mars based on the gaseous inclusions that they have, that are sort of the equivalent of the gases that were shown by the Viking spacecraft” to exist in Mars’ atmosphere, Ruvkun said. In other words, small bubbles of air in these rocks reveal that they were forged in the Martian air. “So, there is exchange between Mars and Earth — probably more often going from Mars to Earth because it goes ‘downhill,’ going to Mars is ‘uphill,’ gravitationally-speaking.”

But for Ruvkun, whose area of expertise is genomics, it’s the timing of cellular life that he believes makes a strong case that life on Earth came from somewhere else — perhaps Mars, or perhaps Mars vis-a-vis another planet.

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Ruvkun noted that our genomes reveal the history of life, and provide clues about the ancestors that preceded us by millions or even billions of years. “In our genomes, you can kind of see the history, right?” he said. “There’s the RNA world that predated the DNA world and it’s very well supported by all kinds of current biology; so, we know the steps that evolution took in order to get to where we are now.”

Thanks to the advancement of genomics, the understanding of LUCA (the Last Universal Common Ancestor) — meaning the organism from which all life on Earth evolved from — has greatly advanced. By studying the genetics of all organisms on Earth, scientists have a very good sense of what the single-celled ancestor of every living thing (on Earth) looked like. They also know the timeline: all modern life forms descend from a single-celled organism that lived about 3.9 billion years ago, only 200 million years after the first appearance of liquid water. In the grand scheme of the universe, that’s not that long.

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And the last universal common ancestor was fairly complicated as far as organisms go. That leaves two possibilities, Ruvkun says. “Either evolution to full-on modern genomes is really easy, or the reason you see it so fast was that we just ‘caught’ life, it didn’t actually start here.” He adds, “I like the idea that we just caught it and that’s why it’s so fast, but I’m an outlier.”

If that’s the case, then Erik Asphaug, is a professor of planetary science at the University of Arizona, is also an outlier. Asphaug said that what we know about the oldest rocks on Earth — which have chemical evidence of carbon isotopes, tracing back to nearly 4 billion years ago — tell us that life started “started forming on Earth almost as soon as it was possible for it to happen.”

If that’s the case, it makes for an interesting precedent. “Let’s say you expect life to be flourishing whenever a planet cools down to the point where it can start to have liquid water,” Asphaug said. “But just looking at our own solar system, what planet was likely to be habitable first? Almost certainly Mars.”

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This is because, Asphaug said, Mars formed before Earth did. Early in Martian history when Mars was cooling down, Mars would have had a “hospitable” environment before Earth.

“If life was going to start anywhere it might start first on Mars,” Asphaug said. “We don’t know what the requirement is — you know, if it required something super special like the existence of a moon or some factors that are unique to the Earth — but just in terms of what place had liquid water first, that would have been Mars.”

An intriguing and convincing piece of evidence relates to how material moved between the two neighboring planets. Indeed, the further you go back in time, the bigger the collisions of rocks between Mars and Earth, Asphaug said. These impact events could have been huge “mountain-sized blocks of Mars” that were launched into space. Such massive asteroids could serve as a home for a hardy microorganism.

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“When you collide back into a planet, some fraction of that mountain-sized mass is going to survive as debris on the surface,” he said. “It’s taken a while for modeling to show that you can have a relatively intact survival of what we call ‘ballistic panspermia’ — firing a bullet into one planet, knocking bits off, and having it end up on another planet. But it’s feasible, we think it happens, and the trajectory would tend to go from Mars to the Earth, much more likely than from Earth to Mars.”

Asphaug added that surviving the trip, given the mass of the vehicle for the microorganisms, wouldn’t be a problem — and neither would surviving on a new, hospitable planet.

“Any early life form would be resistant to what’s going on at the tail end of planet formation,” he said. “Any organism that’s going to be existing has to be used to the horrific bombardment of impacts, even apart from this, swapping from planet to planet.”

In other words, early microbial life would have been fine with harsh environments and long periods of dormancy. 

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Harvard professor Avi Loeb told Salon via email that one of the Martian rocks found on Earth, ALH 84001, “was not heated along its journey to more than 40 degrees Celsius and could have carried life.”

All three scientists believe that Perseverance might be able to add credibility to the theory of panspermia.

“If you were to go and find remnants of life on Mars, which we hope to do with Perseverance rover and these other Martian adventures, I would be personally surprised if they were not connected at the hip to terrestrial life,” Asphaug said.

Ruvkun said he hopes to be one of the scientists to look for DNA when the sample from Mars hopefully, eventually, returns. 

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“Launching something from Mars is a seriously difficult thing,” he said. 

But what would this mean for human beings, and our existential understanding of who we are and where we came from?

“In that case, we might all be Martians,” Loeb said. He joked that the self-help book “Men are from Mars, Women are from Venus” may have been more right than we know.

Or perhaps, as Ruvkun believes, we’re from a different solar system, and life is just scattering across the universe.

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“To me the idea that it all started on Earth, and every single solar system has their own little evolution of life happening, and they’re all independent — it just seems kind of dumb,” Ruvkun said. “It’s so much more explanatory to say ‘no, it’s spreading, it’s spreading all across the universe, and we caught it too, it didn’t start here,” he added. “And in this moment during the pandemic — what a great moment to pitch the idea. Maybe people will finally believe it.”

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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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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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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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.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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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.”

The Canadian Press. All rights reserved.

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