NASA’s OGO-1 satellite was an artifact from an earlier era in the space age. Launched in 1964, it was on a mission to study our planet’s magnetosphere. Its decades-long journey around our planet came to end over the weekend when the satellite finally reentered Earth’s atmosphere and disintegrated. Its final moments were caught on video.
OGO-1 was part of NASA’s Orbiting Geophysical Observatories project. The mission officially ended in 1971, but it lingered in orbit all these years as one more piece of space junk.
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The satellite came back to NASA’s attention when the University of Arizona’s Catalina Sky Survey (CSS) spotted it on Aug. 25 while searching for asteroids that might impact Earth. Researchers investigated and discovered it was not an asteroid, but rather the forgotten satellite.
The PYF Spotters community on Facebook normally spends its energy on filming airplanes, but was able to capture a video of OGO-1 reentering over Tahiti. It looks like some sort of strange meteor as it blasts across a blue sky, falling to pieces as it goes.
Virtual Telescope Project lead Gianluca Masi was able to document some of the satellite’s last moments of existence. This was a testament to the astronomy community’s ability to calculate and track OGO-1’s orbit.
“While OGO-1 was the first spacecraft to be launched in the OGO series, it will be the last to return home as all other five spacecraft have already decayed from orbit and safely reentered Earth’s atmosphere, landing in various parts of the planet’s oceans,” said NASA in a release last week.
The satellite was never in danger of causing damage on the ground. NASA called its reentry a “a normal final operational occurrence for retired spacecraft.”
OGO-1 was long ago assigned to the history books, but its fate is a reminder of the growing issue of space junk, objects that have outlived their usefulness, but remain in orbit as potential hazards to other spacecraft. Researchers are working on ways to mitigate the problem, but we have a long way to go to clean up the space around us.
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Crocodiles may seem intimidating in the year 2020, but millions of years ago, they were so large, they were capable of eating dinosaurs. These massive North American crocodiles, scientists said, had teeth the “size of bananas.”
According to a new study of Deinosuchus fossils published in the Journal of Vertebrate Paleontology, the creatures lived between 75 million and 82 million years ago. Deinosuchus, which means “terror crocodile,” used their ginormous teeth to eat even the largest of dinosaurs — putting them at the top of the food chain in their ecosystem.
Researchers studied fossils and bite marks on turtle shells and dinosaur bones to create a full picture of Deinosuchus. They said the animal, which grew up to 33 feet in length, was actually more closely related to alligators than crocodiles.
Researchers said nearly everything in their habitat was up for grabs to be eaten by the massive predators.
“Deinosuchus was a giant that must have terrorized dinosaurs that came to the water’s edge to drink,” lead author Adam Cossette, a paleontologist at the New York Institute of Technology, said in a press release Monday. “Until now, the complete animal was unknown. These new specimens we’ve examined reveal a bizarre, monstrous predator with teeth the size of bananas.”
Cossette and co-researcher Christoper Brochu, a paleontologist at the University of Iowa, identified three known species of Deinosuchus: Deinosuchus hatcheri, Deinosuchus riograndensis and Deinosuchus schwimmeri. All three roamed various parts of the U.S., which at the time was cut in half by a shallow sea.
Many aspects of the ancient beasts remain mysterious. They didn’t look like a crocodile or an alligator, and their extremely large noses had huge holes at the tips that are completely unique and without a known purpose.
Ice sheets, and not rushing rivers, sculpted many Martian valleys, according to scientists. The new research suggests ancient Mars wasn’t as warm and wet as we thought, but an expert we spoke to remains unconvinced.
New research published in Nature Geoscience suggests rushing rivers weren’t responsible for the distinctive shape of certain Martian valleys located in the planet’s southern highlands. Rather, these geological features were forged by melting water coursing beneath gigantic glaciers, in a geological process known as subglacial erosion. Ancient Mars, the new research suggests, was likely cold and icy, and not the temperate wet planet it’s often presumed to be.
“Our study challenges the widely held view that most valley networks on Mars were formed by rivers fed by precipitation,” explained Gordon Osinski, a co-author of the new paper and a planetary geologist from Western University, in a Western press release. “While we found evidence consistent with a small handful of valley networks having formed in this way, our observations suggest that the majority formed beneath ice sheets.”
Interestingly, these results, while surprising, seem to match the results from climate models. Computer simulations of ancient Mars suggest the Red Planet was cold and covered with ice some 3.8 billion years ago.
For the new study, Osinski, along with Anna Grau Galofre from Arizona State University and Mark Jellinek from the University of British Columbia, examined satellite photos of 10,276 individual valleys found in 66 valley networks on Mars, which they did using custom-built software. Their algorithm was able to match surface features to specific erosional processes, including glacial, subglacial, fluvial (surface water), and sapping (ground water) erosion.
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“If you look at Earth from a satellite, you see a lot of valleys: Some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape,” explained Grau Galofre in an ASU press release. “Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them.”
Martian valleys were also compared to known subglacial features on Earth. Devon Island, located in the Canadian Arctic, is “one of the best analogues we have for Mars here on Earth,” said Osinski, as it’s a “cold, dry polar desert and we know the glaciation is largely cold-based.”
Of the 66 valley systems studied, the researchers identified 22 as being formed from subglacial erosion: 14 fluvial, nine glacial, three sapping, and 18 indeterminate. These findings are “the first evidence for extensive subglacial erosion driven by channelized meltwater drainage beneath an ancient ice sheet on Mars,” said Jellinek in the ASU press release, adding that these results “demonstrate that only a fraction of valley networks match patterns typical of surface water erosion, which is in marked contrast to the conventional view.”
Bruce Jakosky, a geology professor at the University of Colorado and Principal Investigator on the Mars Atmosphere and Volatile Evolution (MAVEN) mission, described the new analysis as “interesting” but not “definitive.”
“Based on their figures, there appears to be a smooth gradation between the properties of the individual valley networks,” said Jakoskyin an email. “Having a smooth gradation in properties, but classifying them into a limited number of formation processes, seems to leave one open to significant uncertainties.”
As a result, Jakosky is not very confident in the specific numbers used in the study. He was also unimpressed with the relatively small sample size of 66, given the authors’ declaration that “hundreds” of valley networks exist on Mars.
“With the exception of the low number for sapping erosion, this seems consistent with a random distribution between the other processes,” he explained. “That is, even though subglacial erosion is the most prominent, it is not so dominant as to justify a conclusion that they are the major process. That is, they state that subglacial and fluvial dominate, but it looks more roughly equal among all processes.”
To which he added: “Their conclusions should have been that all of the processes that they examined played a role, and we have to look for a climate/environment that could support all of them.”
Scott King a geoscientist from Virginia Tech, found the new result to be reasonable, and even likely.
“I think the problem is that it’s Mars and we have some pretty strong ideas about Mars and sometimes that gets in the way of our looking at the observations,” wrote King in an email. “This is one of those studies that makes us stop and ask ourselves just why did we assume that all the valley networks on Mars were fluvial? Why wouldn’t both fluvial and glacial erosion have occurred on Mars? The climate models tell us that Mars was cold and icy so these researchers asked a very logical question, ‘what kind of valley networks do we see?’”
Indeed, the new data has to be reconciled with other geological evidence from ancient Mars, such as the sites of former lakes and river deltas (including Jezero crater, the destination site for the Mars Perseverance rover), clay formations (as discovered by the Curiosity rover), and even evidence of an ancient mega-tsunami on Mars.
Ancient Mars was wet, but the new paper complicates our understanding of this planet’s past by showing how erosional processes other than free-flowing surface water can sculpt certain geological features. Moving forward, planetary scientists would do well to remember this paper, even if it’s somewhat incomplete. It’s becoming increasingly clear, however, that ancient Mars was a comple
New Zealand’s monster penguins, which lived 62 million years ago, had doppelgangers in Japan, the U.S. and Canada, a study published today in the Journal of Zoological Systematics and Evolutionary Research has found.
Scientists have identified striking similarities between the penguins‘ fossilized bones and those of a group of much younger Northern Hemisphere birds, the plotopterids.
These similarities suggest plotopterids and ancient penguins looked very similar and might help scientists understand how birds started using their wings to swim instead of fly.
Around 62 million years ago, the earliest known penguins swam in tropical seas that almost submerged the land that is now New Zealand. Paleontologists have found the fossilized bones of these ancient waddlers at Waipara, North Canterbury. They have identified nine species, ranging in size from small penguins, the size of today’s Yellow-Eyed Penguin, to 1.6-meter-high monsters.
Plotopterids developed in the Northern Hemisphere much later than penguins, with the first species appearing between 37 and 34 million years ago. Their fossils have been found at a number of sites in North America and Japan. Like penguins, they used their flipper-like wings to swim through the sea. Unlike penguins, which have survived into the modern era, the last plotopterid species became extinct around 25 million years ago.
Dr. Gerald Mayr of the Senckenberg Research Institute and Natural History Museum, Frankfurt, James Goedert of the Burke Museum of Natural History and Culture and University of Washington, U.S., and Canterbury Museum Curators Dr. Paul Scofield and Dr. Vanesa De Pietri compared the fossilized bones of plotopterids with fossil specimens of the giant penguin species Waimanu, Muriwaimanu and Sequiwaimanu from Canterbury Museum’s collection.
They found plotopterids and the ancient penguins had similar long beaks with slit-like nostrils, similar chest and shoulder bones, and similar wings. These similarities suggest both groups of birds were strong swimmers that used their wings to propel them deep underwater in search of food.
Some species of both groups could grow to huge sizes. The largest known plotopterids were over 2 meters long, while some of the giant penguins were up to 1.6 meters tall.
Despite sharing a number of physical features with penguins both ancient and modern, plotopterids are more closely related to boobies, gannets and cormorants than they are to penguins.
“What’s remarkable about all this is that plotopterids and ancient penguins evolved these shared features independently,” says Dr. De Pietri. “This is an example of what we call convergent evolution, when distantly related organisms develop similar morphological traits under similar environmental conditions.”
Dr. Scofield says some large plotopterid species would have looked very similar to the ancient penguins. “These birds evolved in different hemispheres, millions of years apart, but from a distance you would be hard pressed to tell them apart,” he says. “Plotopterids looked like penguins, they swam like penguins, they probably ate like penguins—but they weren’t penguins.”
Dr. Mayr says the parallels in the evolution of the bird groups hint at an explanation for why birds developed the ability to swim with their wings.
“Wing-propelled diving is quite rare among birds; most swimming birds use their feet. We think both penguins and plotodopterids had flying ancestors that would plunge from the air into the water in search of food. Over time these ancestor species got better at swimming and worse at flying.”
Fossils from New Zealand’s giant penguins, including Waimanu and Sequiwaimanu are currently on display alongside life-sized models of the birds in Canterbury Museum’s exhibition, “Ancient New Zealand: Squawkzilla and the Giants,” extended until 16 August 2020.
Comparative osteology of the penguin-like mid Cenozoic Plotopteridae and the earliest true fossil penguins, with comment on the origins of wing-propelled diving, by Gerald Mayr, James L Goedert, Vanesa De Pietri and R Paul Scofield is published in the Journal of Zoological Systematics and Evolutionary Research.
New Zealand’s ancient monster penguins had northern hemisphere doppelgangers (2020, June 30)
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Falerii Novi was once a walled town just north of Rome, likely founded around 241 BC as a relocation site for a Falisci tribe that had rebelled against the Romans. Located on a volcanic plateau, archaeologists surmise that the new site was chosen because it wasn’t as easy to defend, thereby discouraging further uprisings. There were likely some 2,500 residents during the third and fourth centuries BC. The ruins are deep underground, but a team of archaeologists from the University of Cambridge and Ghent University in Belgium have used ground-penetrating radar (GPR) to map the complete city. They described their findings in a recent paper in the journal Antiquity.
Dating back to 1910, when the first patent for a radar system to locate buried objects was filed, GPR has been used to measure the depth of glaciers, to study bedrock and groundwater, and to locate unexploded land mines, buried sewers, and utility lines, among other applications. The 1972 Apollo 17 mission—the final moon-landing mission of NASA’s Apollo program—used a GPR system called the Apollo Lunar Sounder Experiment (ALSE) to record depth information of the lunar surface. The method has also emerged in recent years as a powerful tool for archaeological geophysics, since it is a non-invasive means of detecting and mapping artifacts, features, and key patterns beneath the surface.
GPR is distinct from another popular method, LIDAR, which relies on infrared light from lasers rather than radio waves to map terrain. An electromagnetic pulse is directed into the ground, and any objects or layering (stratigraphy) will be detectable in the reflections picked up by a receiver, just like regular radar. How long it takes for the echoes to return indicates the depth, and different materials will reflect the incoming waves differently. The data can then be plotted to create detailed maps of those underground features.
Falerii Novi was first excavated in the 1990s, and over the ensuing decades archaeologists have identified warehouses, shops, market places, a theater, and a forum using various non-invasive techniques, including magnetometry—a method that measures the direction, strength, or relative change of a magnetic field at a given location to reveal details beneath the surface. But the use of GPR by the British and Belgian team has yielded a much more detailed and complete picture of the site, enabling them to study how the town evolved over several hundred years.
The authors attached their GPR system to the back of an ATV in order to more efficiently survey the 30.5 hectares (about 75 acres) within the ancient city’s walls, taking a reading every 12.5 centimeters. In 2017, using their method, the team found the remains of a large Roman temple, several feet below the town, that would have been roughly the same size as St. Paul’s Cathedral.
This latest analysis revealed a large rectangular structure connected to a network of water pipes, leading to the city’s aqueduct. The authors surmise that it is the remains of an open-air pool (natatio), part of a large public bathing complex. They were also surprised to see two large structures facing each other within a covered passageway (porticus duplex) that they believe was once part of a large public monument near the city’s north gate. It seems to be part of a “sacred topography” of temples around the town’s periphery, previously revealed by magnetometer surveys.
GPR works very well in certain conditions, like uniform sandy soils, but the high electrical conductivity of clays and silts, for example, can significantly dampen signal strength. And rocky sediments will scatter the signal, making it more difficult to pick out the patterns in the noise. “At Falerii Novi, the generally dry conditions in the summer months were well-suited to GPR survey,” the authors wrote, noting, however, that when it did rain, “up to seven days were needed before the ground was sufficiently dry to yield optimal data quality.”
Falerii Novi was a good site to demonstrate the potential of GPR because it is not buried beneath modern buildings, unlike other ancient cities. GPR, particularly when combined with magnetometry, could be a useful tool to study such towns. “Neither [GPR or magnetometry] is able to produce a complete picture of the archaeology,” the authors wrote, noting that the shop units of Falerii Novi, for example, show up in the magnetic data but not in the GPR survey. And while the city’s theater shows up in the magnetic data, the GPR survey provided a much clearer view, including at different depths, yielding insight into its structural form, as well as evidence of the removal of walls via stone-robbing.
The biggest challenge going forward is the sheer amount of data produced by this high-resolution mapping. According to the authors, they have collected a whopping 71.7 million readings from Falerii Novi, equivalent to 28.68 billion data points, or about 4.5GB of raw data per hectare (2.47 acres). It can take as long as 20 hours to document a single hectare, which is why the team is developing automated techniques to speed up the process with computer-aided object detection.
“The astonishing level of detail which we have achieved at Falerii Novi, and the surprising features that GPR has revealed, suggest that this type of survey could transform the way archaeologists investigate urban sites, as total entities,” said co-author Martin Millett of the University of Cambridge, adding that it should be possible to use GPR to survey major ancient cities like Miletus in Turkey, or Nicopolis in Greece. “We still have so much to learn about Roman urban life, and this technology should open up unprecedented opportunities for decades to come.”