Snails transmit a disease that kill a lot of people:
Author: jlamprecht
Video: The Triassic Reptile With Two Faces
Figuring out what this creature’s face actually looked like would take paleontologists years. But understanding this weird animal can help us shine a light on at least one way for ecosystems to bounce back from even the worst mass extinction.
You can view the video here: https://www.youtube.com/watch?v=-8W26SiCylI
VIDEO: How Long Will You Live?
Some information on why you age.
Video: Why Life Seems to Speed Up as We Age
Interesting stuff. I have noticed life "speeding up" as I get older.
Science & Technology: This 3D-Printed Sub Could Be the Future of Undersea Warfare
At a passing glance, this submarine looks like any other.
It stretches a few feet longer and can putz around the ocean a bit farther, but its bulbous torpedo-shaped design is familiar to the first robotic subs that’ve plied the waters for decades. But a closer look at Dive Technologies’ new sub reveals a quiet revolution—from how it works to how it’s made.
This unassuming sub is a new breed of Autonomous Underwater Vehicles, or AUVs, future subs that are bigger, smarter, and can travel farther than ever before. They are changing the rules for underwater military, commercial, and scientific operations, and instead of building these water-delving behemoths in a traditional shipyard, ship makers are 3D printing them.
“Large AUVs will change everything,” says Sam Russo, COO of Dive Technologies. “They bring an enormous payload capability and energy capacity that allows the vehicles to operate on their own in the ocean for days on end.”
But Dive isn’t using your run-of-the-mill MakerBot. Using large scale 3D printers, the Boston-based startup can slash costs, speed up production, and create any submarine imaginable in just a few weeks—from idea to fully-functioning prototype.
Source: Popular Mechanics
Nuclear Power for Space: Latest Trump Space Policy Directive Orders Development of Nuclear Power, Propulsion
WASHINGTON, (Sputnik) – President Donald Trump instructed future US governments to develop nuclear power options to support human settlements on the Moon and Mars and provide propulsion for spacecraft and rovers to explore other planets, according to a new Space Policy Directive released by the White House on Wednesday.
"This memorandum establishes a national strategy to ensure the development and use of SNPP [space nuclear power and propulsion] systems when appropriate to enable and achieve the scientific, exploration, national security, and commercial objectives of the United States," the document, dubbed Space Policy Directive-6, said.
The directive sets a number of goals, including establishing a uranium-based nuclear power plant on the surface of the moon by 2027, and using nuke technology to explore Mars.
The directive also sets a 2030 goal to develop new technology to improve systems that generate electricity using radioactive isotopes. Such systems offer long-term power sources for robotic exploration of planet surfaces and robotic spacecraft to transit the solar system.
The Trump administration set a goal of returning US astronauts to the moon by 2024, building a permanent lunar colony, and sending humans to Mars.
While the directive focuses on developing nuclear power technology for space exploration, it also reflects an effort to maintain current US space exploration plans after Trump leaves office in January, 2021.
Photo: The Arecibo Telescope Has Suffered a Fatal Collapse, Smashing It Into Pieces
The celebrated Arecibo Observatory telescope in Puerto Rico, which once starred in a James Bond film, collapsed Tuesday when its 900-ton receiver platform plunged 450 feet (140 meters) onto the radio dish below.
Engineers had recently warned of the huge structure’s decrepit condition, and the US National Science Foundation (NSF) announced only last month that it would be dismantled.
Two of the cables that held the platform over the radio dish – which measures 1,000 feet (300 meters) in diameter – had snapped this year, and the structure finally gave way on Tuesday morning.
Photographs showed clouds of dust rising into the air and the remains of the telescope instruments scattered across the site.
Aerial view of damage at the Arecibo Observatory on 1 Dec 2020. (Ricardo Arduengo/AFP)
"We can confirm the platform fell and that we have reports of no injuries," Rob Margetta, spokesman for the NSF, told AFP.
The telescope was one of the largest in the world and has been a tool for many astronomical discoveries since the 1960s, as well as being famous for its dramatic scale and setting.
An action scene from the Bond film GoldenEye featuring Pierce Brosnan took place high above the dish, and in Contact, an astronomer played by Jodie Foster used the observatory in her quest for alien signals.
‘Sad day for astronomy’
Abel Mendez, director of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, said the platform fell sometime before 8:00 am (1200 GMT), describing it as "a total disaster".
"Many students are trained in astronomy in the observatory, they are inspired like me to do a career in science and astronomy," he said.
"The loss of the Arecibo telescope is a big loss for the world, but it is more of a loss for Puerto Rico. It is an icon for our island."
Damage sustained at the Arecibo Observatory 305-meter telescope. (UCF)
The telescope was in operation for 57 years until August, and scientists had lobbied the NSF to reverse its decision to close the site.
In August, an auxiliary cable failed after slipping from its socket in one of the towers and left a 100-foot gash in the dish below.
Engineers were assessing the damage and how to repair it when a main cable connected to the same tower broke on November 6.
Before Tuesday, a controlled demolition had been planned to avoid an unexpected collapse.
Among the telescope’s successes was in 1992 discovering the first exoplanet – a planet outside the solar system – and in 1981 it helped produce the first radar maps of the surface of Venus.
The observatory’s website said the telescope was "a world-leading radio astronomy, solar system radar and atmospheric physics facility, contributing highly relevant data to support discovery, innovation and the advancement of science."
"What a sad day for astronomy and planetary science worldwide and one of the most iconic telescopes of all time," tweeted Thomas Zurbuchen, associate administrator at the NASA science mission directorate.
The site had hoped the dismantling plan would preserve other parts of the observatory for future research and education.
"As we move forward, we will be looking for ways to assist the scientific community and maintain our strong relationship with the people of Puerto Rico," the NSF said in a tweet.
Source: https://www.sciencealert.com/the-arecibo-telescope-platform-has-collapsed
Photo: Controversial 7-Million-Year-Old Skull May Not Have Been as Human as We Thought
[I have no opinion on this. It's just interesting science. What if any implications this might have, I don't know. Jan]
The question of whether a 7-million-year-old primate, nicknamed ‘Toumai,’ walked on two or four legs has whipped up drama amongst palaeontologists – complete with a vanishing femur.
Since the discovery of Sahelanthropus tchadensis’s first fossil back in 2001, it has often been cited as our earliest known hominin ancestor. Initial analysis suggested that Sahelanthropus regularly walked upright and had a combination of ape-like and human-like features.
These conclusions, however, were based on a single skull.
The skull has anatomical features that potentially indicate this primate had an erect spine, and therefore spent some of its time walking on two legs only. Its small teeth also appear more human than ape-like. A later reconstruction supported these findings.
But other researchers have since argued that this alone is not enough evidence to class Sahelanthropus as a hominin biped – a primate directly ancestral to humans – rather than a related, but not directly ancestral hominid.
Around the same time and at the same location where the skull was found, in Toros-Menalla in Chad, a partial left femur was also recovered. The femur vanished after another researcher started to examine it in 2004, having come across it supposedly by chance.
Aude Bergeret-Medina and her supervisor, palaeoanthropologist Roberto Macchiarelli from the University of Poitiers in France, eventually continued their analysis based on measurements and photos. They have just published their findings, which cast doubt on Sahelanthropus’s place in our family tree.
"Based on our analyses, the partial femur lacks any feature consistent with regular bouts of terrestrial bipedal travel," Macchiarelli and team write in their paper.
"Thus, if there is compelling evidence that S. tchadensis is a stem hominin, then bipedalism can no longer be seen as a requirement for inclusion in the hominin clade."
Another paper still awaiting peer review from one of the authors of the original Sahelanthropus studies disputes this, claiming the femur has a hard top ridge that supports an upright stance.
Meanwhile, another palaeontologist, Martin Pickford from the French National Museum of Natural History, wonders if the femur even belongs to Toumai, or at least another Sahelanthropus.
Still, others agree with Macchiarelli’s assessment of the femur.
"I saw the pictures 10 or 12 years ago, and it was clear to me that it’s more similar to a chimp than to any other hominin," University of Tübingen palaeontologist Madelaine Böhme, who was not involved in any of the studies, told New Scientist.
Analysis of molecular differences in our DNA suggests that humans parted ways with chimpanzees and bonobos (our closest still living relatives), around 6-8 million years ago. The only other fossil evidence of a possible hominin from that time is from Orrorin tugenensis.
Macchiarelli and team compared the femur with one from O. tugenensis and determined that there’s at least species-level difference between them.
After also comparing them with Australopithecus, gorillas, and modern humans, they believe these differences suggest the mode of locomotion of the two oldest species was also different.
They suspect Sahelanthropus may be an ancestral relative with no remaining living descendants – a primate lineage that went extinct.
They also point out others have suggested the small teeth found in the original study could just indicate the primate is female. But the team agrees that fascinating questions nonetheless remain, particularly around the lines that we use to define what exactly makes a primate a human, quoting a 2017 paper in their conclusion:
"Exactly where in Africa, and under what circumstances, the ape-human demarcation began, and when, how and why the ape-human boundary became irrevocably established, are important research challenges that are still unresolved."
We’ll need many more fossils before we know the answers.
This research was published in the Journal of Human Evolution.
Photo: Asteroid Apophis is speeding up as scientists recalculate odds of 2068 impact
[It is fascinating that this asteroid might hit the earth by 2068. But there are unknowns due to slight orbital changes. Either way, Western Science can handle it. They can also push it away from hitting the earth. This is probably the easiest and most practical solution to the problem. Jan]
Astronomers say they’ll have to keep an eye on the near-Earth asteroid Apophis to see how much of a danger the space rock poses to our planet during a close pass in 2068. But don’t panic: The chances of an impact still seem very low.
Under certain circumstances, the sun can heat an asteroid unevenly, causing the space rock to radiate away heat energy asymmetrically. The result can be a tiny push in a certain direction — an effect called Yarkovsky acceleration, which can change the path of an asteroid through space.
Since astronomers hadn’t measured this solar push on Apophis before, they didn’t take it into consideration when calculating the threat the asteroid poses to us in 2068. Those previous calculations showed a tiny impact probability — around 1 in 150,000.
CLOSE
Now, a new study shows the asteroid is drifting away from its previously predicted orbit by about 557 feet (170 meters) a year due to the Yarkovsky effect, lead author and University of Hawaii at Manoa astronomer David Tholen said during a press conference on Oct. 26.
"Basically, the heat that an asteroid radiates gives it a very tiny push," he explained during a virtual meeting of the American Astronomical Society’s Division for Planetary Sciences. You can find the press conference on YouTube here. It begins at the 22-minute mark.
"The warmer hemisphere [of the asteroid] would be pushing slightly more than the cooler hemisphere, and that causes the asteroid to drift away from what a purely gravitational orbit would predict," Tholen said.
Showing the orbit for the 1,120-foot-wide (340 m) Apophis, he indicated that astronomers thought they had enough observations of the asteroid — collected over the years after its discovery in 2004 — to more or less rule out an impact in 2068. Those calculations, however, were based on an orbit not affected by the sun’s energy. Ultimately, this means we can’t yet rule out Apophis being a threat in 2068, Tholen said.
"The 2068 impact scenario is still in play," Tholen said. "We need to track this asteroid very carefully."
Fortunately, the asteroid will make a close (yet still safe) approach to our planet in 2029, allowing ground-based telescopes — including the Arecibo Observatory’s powerful radar dish — to get a more detailed look at the asteroid’s surface and shape. Apophis will be so close it will be visible with the naked eye, at third magnitude — about as bright as the binary star Cor Caroli.
"Of all dates, Friday the 13th in April, April 13 [2029], is when the flyby will occur," Tholen said., "Obviously, the 2029 close approach is critical. We’ll know after that occurs exactly where it [Apophis] was as it passed the Earth, and that will make it much easier for us to predict future impact scenarios."
Tholen’s team made the discovery after four nights of observation in January and March with the Subaru Telescope, a Japanese optical-infrared telescope on the summit of Maunakea, Hawaii. The researchers collected 18 exposures of the asteroid at a very high precision, with an error of only 10 milliarcseconds in each observation. (A milliarcsecond is a thousandth of an arcsecond, an angular measurement that helps scientists measure cosmic distances.)
"We really nailed the position of this asteroid extremely well," Tholen said. "That was enough to give us a strong detection of the Yarkovsky effect, which is something we’ve been expecting to see now for a while."
Tholen noted that Apophis has been troublesome for astronomers, with "numerous impact scenarios" predicted (and then largely ruled out) since it was first found in 2004. For example: Initially, scientists calculated a 3% chance of Apophis slamming into our planet in 2029, a prediction Tholen said was quickly ruled out after more observations showed the true path of the little world.
If there’s any threat of an impact, astronomers will know long before 2068 how to approach the problem. Engineers around the world are developing ideas about how to deflect dangerous asteroids from our planet, concepts that range from gravitational tugs to "kinetic impactors" that would knock an incoming rock off course.
A joint European-NASA mission will also test and observe asteroid deflection at a space rock called Didymos, starting in 2022. If all goes to plan, NASA’s Double Asteroid Redirection Test (DART) spacecraft will slam into "Didymoon," the moon orbiting Didymos. The European Space Agency will then launch the Hera mission in 2023 or 2024 and reach Didymos two years later, to see how well the kinetic impactor did in moving the moon from its previous orbit.
NASA has a dedicated Planetary Defense Coordination Office that collects asteroid observations from a network of partner telescopes, and which runs through scenarios with other U.S. agencies for asteroid deflection or (in the worst case) evacuating threatened populations from an incoming space rock. So far, decades of observations have found no imminent asteroid or comet threats to our planet.
Mystery ancestor mated with ancient humans. And its ‘nested’ DNA was just found.
Today’s humans carry the genes of an ancient, unknown ancestor, left there by hominin species intermingling perhaps a million years ago.
The ancestor may have been Homo erectus, but no one knows for sure — the genome of that extinct species of human has never been sequenced, said Adam Siepel, a computational biologist at Cold Spring Harbor Laboratory and one of the authors of a new paper examining the relationships of ancient human ancestors.
The new research, published today (Aug. 6) in the journal PLOS Genetics, also finds that ancient humans mated with Neanderthals between 200,000 and 300,000 years ago, well before the more recent, and better-known mixing of the two species occurred, after Homo sapiens migrated in large numbers out of Africa and into Europe 50,000 years ago. Thanks to this ancient mixing event, Neanderthals actually owe between 3% and 7% of their genomes to ancient Homo sapiens, the researchers reported.
"Our best conjecture is that an early group of anatomically modern humans left Africa then encountered and interbred with Neandertals, perhaps in the Middle East," Siepel told Live Science. "This lineage [of humans] would then have been lost — either gone extinct, or absorbed by the Neandertals, or migrated back to Africa."
Ancient mixers
The new research illustrates the complexity of humanity’s deep history. Evidence has long been accumulating that humans and Neanderthals mated while their populations overlapped in Europe, before Neanderthals went extinct around 30,000 years ago. In 2010, researchers reported that between 1% and 4% of modern human genes in people in Asia, Europe and Oceania came from Neanderthal ancestors. When you add up all the snippets of Neanderthal DNA present in all modern humans today, some 20% of the Neanderthal genome may be preserved, according to 2014 research.
As scientists have been able to sequence more fragile fragments of DNA from fossils of ancient human ancestors, they’ve discovered a complex web of interbreeding stretching back millennia. Some Pacific Islanders, for example, carry pieces of the DNA of a mysterious ancient species of humans known as Denisovans.
The researchers of the new study used a computational method of comparing the genomes of two Neanderthals, a Denisovan and two modern African individuals. (Africans were chosen because modern people in Africa don’t carry Neanderthal genes from the well-known human-Neanderthal interbreeding that occurred in Europe starting 50,000 years ago.) This method allowed the researchers to capture recombination events, in which segments of chromosomes — which are made up of DNA — from one individual get incorporated into the chromosomes of another.
"We are trying to build a complete model for the evolutionary history of every segment of the genome, jointly across all of the analyzed individuals," Siepel said. "The ancestral recombination graph, as it is known, includes a tree that captures the relationships among all individuals at every position along the genome, and the recombination events that cause those trees to change from one position to the next."
One advantage of the method, Siepel said, is that it allows researchers to find recombination events inside of recombination events. For example, if a bit of ancient hominin DNA from an unknown ancestor were incorporated in the Neanderthal genome, and then a later mating event between Neanderthals and humans inserted that mystery DNA into the human genome, the method allows for the identification of this "nested" DNA.
The analysis turned up evidence of this sort of nested insertion of DNA. The finding that Homo sapiens seem to have mated with Neanderthals between 200,000 and 300,000 years ago meshes with previous evidence of some sort of mixing event between the two species prior to humans moving en masse to Europe, Siepel said.
The researchers also found that 1% of the Denisovan genome hails from the genes of an unknown ancestor, from an interbreeding event that must have happened, roughly, a million years ago. This mystery ancestor could have been Homo erectus, Siepel said, because Homo erectus likely did overlap in Eurasia with the ancestors of Denisovans and Neanderthals. However, these fragments are tiny and there are no Homo erectus sequences to compare them to, so this is speculative.
In both cases, these interbreeding events were passed along again to modern humans: 15% of the interbreeding sequences found in Denisovans are present in people living today, the researchers found.
The new results are another piece of evidence that ancient and modern human lineages mixed relatively frequently, Siepel said.
"A picture is emerging of a series of distinct but related populations moving around the globe and frequently interacting with one another, with occasional interbreeding events that produced hybrid offspring," Siepel said. "These hybrid offspring might in some cases have suffered from reduced fitness — this is an area of controversy — but apparently many of them were healthy enough to survive and reproduce, leaving a patchwork of archaic and modern human DNA in Neanderthals, Denisovans and modern humans.
Source: https://www.livescience.com/mystery-ancestor-mated-with-humans.html
Source: https://www.livescience.com/mystery-ancestor-mated-with-humans.html