SpaceX to launch first-ever private astronaut mission in late 2021 - Business Insider - Business Insider

Mysterious magnetic fossils offer past climate clues - Phys.org

Electron microscope images of giant needles. Needles have a cylindrical shape and some taper toward one end of the crystal. Credit: Courtney Wagner, Ioan Lascu and Kenneth Livi.

There are fossils, found in ancient marine sediments and made up of no more than a few magnetic nanoparticles, that can tell us a whole lot about the climate of the past, especially episodes of abrupt global warming. Now, researchers including doctoral student Courtney Wagner and associate professor Peter Lippert from the University of Utah, have found a way to glean the valuable information in those fossils without having to crush the scarce samples into a fine powder. Their results are published in Proceedings of the National Academy of Sciences.

"It's so fun to be a part of a discovery like this, something that can be used by other researchers studying magnetofossils and intervals of planetary change," Wagner says. "This work can be used by many other scientists, within and outside our specialized community. This is very exciting and fulfilling."

The name "magnetofossil" may bring to mind images of the X-Men, but the reality is that magnetofossils are microscopic bacterial iron fossils. Some bacteria make magnetic particles 1/1000 the width of a hair that, when assembled into a chain within the cell, act like a nano-scale compass. The bacteria, called "magnetotactic bacteria," can then use this compass to align themselves to the Earth's magnetic field and travel efficiently to their favorite chemical conditions within the water.

During a few periods in the Earth's past, at the beginning and middle of the Eocene epoch from 56 to 34 million years ago, some of these biologically-produced magnets grew to "giant" sizes, about 20 times larger than typical magnetofossils, and into exotic shapes such as needles, spindles, spearheads and giant bullets. Because the bacteria used their magnetic supersense to find their preferred levels of nutrients and oxygen in the ocean water, and because the giant magnetofossils are associated with periods of rapid climate change and elevated global temperature, they can tell us a lot about the conditions of the ocean during that rapid warming, and especially how those conditions changed over time.

Previously, extraction and analysis of these fossils required crushing the samples into a fine powder for electron microscopy imaging. "The extraction process can be time-consuming and unsuccessful, electron microscopy can be costly, and the destruction of samples means that they are no longer useful for most other experiments," Wagner says. "Collection and storage of these samples require specialized personnel, equipment and planning, so we want to preserve as much material for additional studies as we can."

So Wagner, Lippert and colleagues including Ramon Egli from the Central Institute for Meteorology and Geodynamics and Ioan Lascu at the National Museum of Natural History, found another way. Using sediment samples collected in New Jersey, they designed a new way of conducting an analysis called FORC (first order reversal curve) measurements. With these high-resolution magnetic measurements, they found that the magnetic signature of giant magnetofossils was distinctive—enough that the technique could be used in other samples to identify the presence of the fossils. "FORC measurements probe the reaction of magnetic particles to externally applied magnetic fields, enabling to discriminate among different types of iron oxide particles without actually seeing them," says Egli.

"The ability to rapidly find giant magnetofossil assemblages in the geologic record will help to identify the origin of these unusual magnetofossils," the researchers write, as well as the ecology of the organisms that formed them. This is important, Wagner says, because no known living organisms form giant magnetofossils today, and we still don't know what organisms formed them in the past. "The organisms that produced these giant magnetofossils are utterly mysterious, but this leaves exciting research avenues open for the future" adds Lascu.

Beyond that, though, the information contained in magnetofossils helps scientists understand how oceans responded to past climate changes—and how our current ocean might respond to ongoing warming.

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Explore further

Microbiologists discover key protein for controlling cell shape in magnetic bacteria

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More information: Courtney L. Wagner el al., "In situ magnetic identification of giant, needle-shaped magnetofossils in Paleocene–Eocene Thermal Maximum sediments," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2018169118

Provided by University of Utah

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SpaceX announces first space mission with all-civilian crew - CNBC Television

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1. SpaceX announces first space mission with all-civilian crew  CNBC Television
2. SpaceX to fly first civilian crew to space later this year, with public competitions for two seats  CNBC
3. SpaceX announces first-ever all-civilian space flight crew  CNN
4. SpaceX announces first mission to space with all-civilian crew  NBC News
5. To Get on This SpaceX Flight, You Don’t Have to Be Rich, Just Lucky  The New York Times
6. View Full Coverage on Google News

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The Skin-Deep Physics of Sidewinder Snakes - The New York Times

A close-up on snake skin helped scientists work out what might help certain snakes navigate sandy surfaces.

When it comes to slithering, most snakes do it the same way: straight ahead. But for snakes that live in deserts, getting around can be a challenge.

“As we know from trying to move on sand in a beach or other places, it can be difficult to move on these materials that yield underneath you as you move forward,” said Jennifer Rieser, a professor of physics at Emory University in Atlanta.

That’s why sidewinders slither sideways. Although some snakes can move laterally under certain conditions, Dr. Rieser said, sidewinders — the common name for a group of three distantly-related vipers found in the deserts of Africa, the Middle East and North America — have raised this unique form of movement to an art. The sidewinding rattlesnake, for example, can travel at speeds of 18 miles per hour, making it the fastest snake in the world.

Now a new study by Dr. Rieser and her colleagues may have found their secret: scales packed with tiny pits, instead of the minuscule spikes found on the bottom of other snakes. Their research was published on Monday in Proceedings of the National Academy of Sciences.

The microstructure of snake bellies is important to how they move, Dr. Rieser said, because that’s how limbless animals interact with the ground. To examine the microstructure of sidewinder scales, her team used an atomic force microscope to scan naturally shed snake skins, provided by institutions such as the Atlanta Zoo. They then built mathematical models to test how the structures they saw would perform under different kinds of friction.

A micrograph of the skin of the Saharan sand viper, a sidewinder, reveals that its belly is studded with pits instead of spikes. This image shows a surface about 20 microns wide, or about a third of the width of a human hair.Reiser et al., PNAS 2021

A micrograph of the skin from the belly of a Mexican lance-headed rattlesnake, which slithers forward, revealing spikes that are normally invisible to the eye. The micrograph image shows a surface 20 microns wide.Reiser et al., PNAS 2021

Although they appear smooth to the naked eye, the belly scales of most snakes have microscopic spikes that are oriented from head to tail. These create a friction between the snake’s body and the ground, Dr. Rieser said, which helps them move forward in a familiar headfirst slither.

Snakes from a wide variety of habitats and ecological roles — including close relatives of the sidewinder rattlesnake, such as cottonmouths or diamondback rattlesnakes — have these prominent spikes on their bellies.

But sidewinding species have either reduced or phased out those spikes, trading them in for belly scales that are pocked with microscopic pits that can move in any particular direction. Dr. Rieser suggests that’s because directional friction makes movement in a frictionless environment harder: “Picture a snake trying to move on linoleum or silk.”

Sidewinding instead depends on lifting large chunks of the body into the air as the animal moves. Scales that create strong directional friction, Dr. Rieser said, do very badly with this kind of movement. But if scale friction is uniform in all directions, it makes sidewinding significantly easier.

The Saharan horned viper and the sidewinding adder of the Namib desert — which are closely related — have belly scales with uniform pits and no spikes. But the sidewinding rattlesnake, which comes from a different branch of the viper family tree, still has a few vestigial belly spikes as well as pits.

One possible explanation for the difference is that the deserts of the North American southwest are only 15,000 to 20,000 years old, compared with the North African deserts, which are seven million to 10 million years old.

“So maybe there’s been less time for American sidewinders to evolve structures that might help this type of movement,” Dr. Rieser said.

While the team’s hypothesis about the precise function of the microscopic pits will require additional study, the loss or reduction of these belly spikes in distantly-related sidewinders suggests that these changes are a direct adaptation to sideways movement, they suggest.

“Given that movement is so crucial to survival, it’s reasonable to think that’s part of the reason this change has occurred,” Dr. Rieser said.

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Watch NASA astronauts conduct the second spacewalk of the year - CNN

This is the second spacewalk for the duo in just a matter of days. It began at 7:56 a.m. ET, with live coverage streaming on NASA's website. The spacewalk is expected to last for six and a half hours.

It's the second spacewalk experience for Glover, who is a few months into his first spaceflight on the station.

"What a beautiful view," Glover said after he began his spacewalk last Wednesday.

This will be the fourth spacewalk for Hopkins, who previously completed two spacewalks during his first six-month stay on the space station from September 2013 to March 2014.

This is the 234th spacewalk in support of the space station's assembly, maintenance and upgrades.

Hopkins will wear the spacesuit bearing red stripes as crew member 1 and Glover will be in the spacesuit with no stripes as crew member 2.

The astronauts will install the final lithium-ion battery adapter plate on Monday. They will connect it to the battery, which was installed robotically ahead of the spacewalk. This installation wraps up work to complete the replacement of aging nickel-hydrogen batteries outside the station that began in January 2017.

Glover and Hopkins will then move to the opposite side of the station to focus on other upgrades. Their work includes replacing an external standard camera with a new high-definition camera on the Destiny laboratory, and replacing camera and light assembly components needed for the Japanese robotic arm's camera system, located outside of the Kibo module. They will also route some ethernet cables.

Hopkins, Glover, NASA astronaut Shannon Walker and Japan Aerospace Exploration Agency astronaut Soichi Noguchi flew to the station in November aboard the SpaceX Crew Dragon Resilience spacecraft in mid-November. They joined NASA astronaut Kate Rubins and Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov, who were already on the station after launching in October.

Rubins has the task of operating the robotic arm from inside the space station to assist the astronauts as they work outside.

There are more spacewalks planned for the crew near the end of February and beginning of March.

Glover and Rubins will pair up for the third spacewalk to prepare the station's power system for installing new solar arrays, which will increase the station's power supply.

Rubins and Noguchi will conduct the fourth spacewalk to continue upgrades for the space station.

During these long spacewalks, the astronauts go through alternating cycles of day and night every 45 minutes, operating against the hot, bright light of the sun as well as the cold darkness of space. This happens because the space station is orbiting the Earth at 17,500 miles per hour.

While the astronauts don't feel the direct impacts of extreme cold and heat, there is the potential for a chill, so there are heaters installed in the astronauts' gloves to keep their hands warm, said Vincent LaCourt, spacewalk flight director at NASA for the February 1 spacewalk.

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This Insane Picture of The Moon Was Actually Taken From Earth - ScienceAlert

A test of a powerful new space imaging instrument has given us a gloriously detailed new perspective of the Apollo 15 Moon landing site.

By bouncing a powerful radar signal off the lunar surface, the new instrument has been able to achieve spectacular resolution, showing objects as small as 5 metres (16.4 feet).

Designed for the Green Bank Telescope in West Virginia by Raytheon Intelligence & Space, this proof-of-concept technology paves the way for even more powerful radar imaging in the future, potentially allowing scientists to study objects even as far away as Neptune.

Radar imaging of the Moon is not a new idea, however. It's an extraordinarily useful tool for revealing fine structures on the surface and, at longer wavelengths, even probing over 10 metres below the surface to observe variations in the density of the regolith (here on Earth, this technology can help us find buried ruins).

But the Green Bank Observatory, the National Radio Astronomy Observatory, and Raytheon Intelligence & Space are trying to push the technology even further.

(Sophia Dagnello, NRAO/GBO/Raytheon/AUI/NSF/USGS)

In a test in November of last year, the new transmitter sent out a radar signal to the Moon, specifically targeting the Apollo 15 landing site - a small patch of Moon, on a disc 3,474.2 kilometres (2,158.8 miles) in diameter, hundreds of thousands of kilometres away.

This signal, when it bounced back, was collected by the Very Long Baseline Array. This is a collection of radio telescopes across the US, basically combining to create a continent-sized collecting dish.

The image below is the result. That divot in the top middle is a crater called Hadley C, about 6 kilometres across. Snaking past it is the Hadley Rille, thought to be a collapsed lava tube.

(NRAO/GBO/Raytheon/NSF/AUI)

Believe it or not, though, this ain't even the half of it. Now that they have successfully proven the concept, the team will be working on an even more powerful transmitter: a 500-kilowatt, high-power radar system that will enable them to see in even more incredible detail.

This tool would be useful for all sorts of science. We could see our Moon more closely, sure. We could see other planets' moons. It could even be used to image passing asteroids and space debris, which are too faint to see using optical telescopes, but that we can probe using radar technology.

This could help us better understand the population of objects - both natural and anthropogenic - in near-Earth space, which in turn could aid in planetary defence against potentially hazardous objects.

"The planned system will be a leap forward in radar science, allowing access to never before seen features of the Solar System from right here on Earth," said site director Karen O'Neil of the Green Bank Observatory.

And if it gets us even more incredible pictures of the Moon, we're so here for it.

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Ancient Jersey teeth find hints at Neanderthal mixing - Yahoo News

The Neanderthal specimens have some features that are more characteristic of modern human teeth

Prehistoric teeth unearthed at a site in Jersey reveal signs of interbreeding between Neanderthals and our own species, scientists say.

UK experts re-studied 13 teeth found between 1910 and 1911 at La Cotte de St Brelade in the island's south-west.

They were long regarded as being typical Neanderthal specimens, but the reassessment also uncovered features characteristic of modern human teeth.

The teeth may represent some of the last known Neanderthal remains.

As such, they might even yield clues to what caused the disappearance of our close evolutionary cousins.

The Neanderthals evolved around 400,000 years ago and inhabited a large area from western Europe to Siberia.

They were typically shorter and stockier than modern humans, with a thick ridge of bone overhanging the eyes.

They finally disappeared around 40,000 years ago, just as anatomically modern humans (Homo sapiens), a newly arrived species from Africa, was settling in Europe.

However, the two types of human may have overlapped for at least 5,000 years.

The teeth were discovered on a small granite ledge at the cave site.

They were previously thought to belong to a single Neanderthal individual. However, the new research found they were from at least two adults.

The researchers used computed tomography (CT) scans of the teeth to study them at a level of detail that wasn't available to researchers in the past.

'Dual ancestry'

While all the specimens have some Neanderthal characteristics, some aspects of their shape are more typical of teeth from modern humans.

This suggests these were traits that were prevalent in their population.

Research leader Prof Chris Stringer, from London's Natural History Museum, said: "Given that modern humans overlapped with Neanderthals in some parts of Europe after 45,000 years ago, the unusual features of these La Cotte individuals suggest that they could have had a dual Neanderthal-modern human ancestry."

At the time these individuals were alive, the climate in this part of the world was colder than it is today and the sea level was tens of metres lower.

Co-author Dr Matt Pope, from the Institute of Archaeology at University College London (UCL), said the area would have been "fantastic for hunting", because of its "dead-end valleys and blind gulleys".

"Caves of that scale and size are extremely rare in that landscape," he said, adding: "It seems to be embedded in their routines, coming back to that place for tens of thousands of years."

The specimens were originally excavated more than 100 years ago

In fact, there is a record of occupation at the La Cotte site going back to 250,000 years ago.

The human teeth are thought to be around 48,000 years old, close to the presumed Neanderthal extinction date of 40,000 years ago.

So, rather than going extinct in the traditional sense, were Neanderthal groups simply absorbed into incoming modern human populations?

"This now needs to be a scenario that's seriously considered, alongside others, and it's going to emerge as we get more understanding of the process of genetic admixture," Dr Pope told BBC News.

"But certainly, that word 'extinct' now starts to lose its meaning where you can see multiple episodes of admixture and the retention of a significant proportion of Neanderthal DNA in humans beyond sub-Saharan Africa."

Neanderthals contributed 2-3% of the genomes - the genetic instruction booklet for making a person - of people with ancestry from outside Africa.

"This idea of a hybrid population could be tested by the recovery of ancient DNA from the teeth, something that is now under investigation," said Prof Stringer.

The study has been published in the Journal of Human Evolution.

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