понедельник, 9 декабря 2019 г.

GOCE reveals what’s going on deep below Antarctica

ESA - GOCE Mission logo.

Dec. 9, 2019

Antarctica: below the surface

Despite having completed its mission in orbit over six years ago, ESA’s GOCE gravity mapper continues to yield new insights into our planet. Thanks to this extraordinary satellite, scientists now have a much clearer view of the secrets that lie deep below one of the most remote parts of the world: Antarctica. And while the vast expanse of white ice above may appear relatively uniform, it is a very different story below the bedrock.

A layer of ice up to 4 km thick, fierce winds and temperatures that can reach –60°C make Antarctica one of the harshest environments on Earth. This, coupled with the remoteness of this vast icy continent, means that it is difficult and expensive to carry out scientific research, particularly into what lies beneath deep below. Thankfully, data collected from space can offer information that field experiments alone cannot.

A paper, published recently in the Journal of Geophysical Research: Solid Earth, describes how scientists used gravity data from the GOCE satellite mission along with seismological models to reveal unprecedented insight into the crust and upper mantle, otherwise known as the lithosphere, below this frozen continent.

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Piper Sike Roman Turret (Turret 51a), Brampton, Hadrian’s Wall, 8.12.19.

Piper Sike Roman Turret (Turret 51a), Brampton, Hadrian’s Wall, 8.12.19.

* This article was originally published here

Dull teeth, long skulls, specialized bites evolved in unrelated plant-eating dinosaurs

Herbivorous dinosaurs evolved many times during the 180 million-year Mesozoic era, and while they didn't all evolve to chew, swallow, and digest their food in the same way, a few specific strategies appeared time and time again. An investigation of the skulls of 160 non-avian dinosaurs revealed the evolution of common traits in the skulls and teeth of plant-eating members of otherwise very different families of these extinct reptiles. These new examples of convergent evolution in plant-eating dinosaurs appear in the journal Current Biology.

Dull teeth, long skulls, specialized bites evolved in unrelated plant-eating dinosaurs
An illustration of the changes observed in the skulls of different groups of herbivorous dinosaurs
[Credit: Button and Zanno, 2019]
"People often think of dinosaurs as a swansong for extinction or that they were a failed species. But they were actually extremely successful in terms of how different species' anatomies evolved--particularly in herbivores," says co-senior author David J. Button, a paleontologist at the Natural History Museum, London.

By looking at herbivorous and carnivorous dinosaur skulls, Button and co-senior author Lindsay Zanno, a professor at North Carolina State University and the head of paleontology at the North Carolina Museum of Natural Sciences, found that while there are many ways for dinosaurs that eat similar foods to evolve, some traits reappear during evolution, even in unrelated species.

Herbivorous dinosaurs came in all shapes and sizes. Some exhibited dull, flat teeth like horses, while others had beaked faces like tortoises; some developed towering necks like giraffes, while others mimicked the short and stout build of a rhino. "Nonetheless, we see the evolution of common traits in the skull between these otherwise very different herbivorous dinosaur groups," explains Button.

"For example, both the ostrich-like ornithomimosaurs and giant titanosaurs independently evolved elongate skulls and weaker bites, whereas the horned ceratopsians and gazelle-like ornithopods sported more powerful jaws and grinding teeth," he says. These are results of convergent evolution, where adaptation to a diet of plants led to the evolution of common characters in different dinosaur groups.

Dull teeth, long skulls, specialized bites evolved in unrelated plant-eating dinosaurs
An illustration of herbivorous dinosaur lineages skull anatomies changing in similar ways
over the course of evolution [Credit: Button and Zanno, 2019]
The researchers hypothesized that some traits would be most common in plant-eaters. Slow-moving dinosaurs with small heads and dull teeth would likely have a difficult time wrapping their jaws around the neck of another dinosaur, in the way a carnivore like the Tyrannosaurus is thought to have done with ease. Instead, eating plants poses other challenges, such as grinding down tough plant stems.

"There's a tradeoff between biting speed and biting efficiency," says Button. "If you're a herbivorous animal, you don't really need speed because plants don't move very fast."

Some of the results of this functional analysis surprised the researchers, however. That was the case when investigating the eating habits of ankylosaurs, armored, armadillo-like plant-eating dinosaurs with small teeth and a large stomach cavity. Researchers previously thought dinosaurs with these traits usually swallowed their food nearly whole and let their gut break it down. "In our results, we found that ankylosaurs actually may have chewed their food more thoroughly than is often thought. So, that was interesting," says Button.

In the future, Button and Zanno hope to look at the entire skeleton of herbivorous dinosaurs for similar, reoccurring traits. They also plan to expand this work to better understand predominate traits in carnivores, though Button admits plant-eaters will always be his favorite dinosaurs to study.

"People think that carnivorous dinosaurs are super exciting and cool because they run fast, and kill stuff," he says. "But I think the plant-eating dinosaurs evolved in much more interesting and sophisticated ways. That's what makes this work so exciting."

Source: Cell Press [December 05, 2019]

* This article was originally published here

Russian Space Freighter Docks Automatically to Station

ROSCOSMOS - Russian Vehicles patch.

December 9, 2019

Image above: Russia’s Progress 73 cargo craft is pictured departing the International Space Station on Nov. 29, 2019. Image Credit: NASA.

Traveling approximately 260 miles over the Yellow Sea east of Shanghai, the automated Russian Progress 74 cargo resupply spacecraft docked at 5:35 a.m. EST to the Pirs docking compartment on the Russian segment of the International Space Station.

It is the second resupply spacecraft to arrive for the six crew members aboard the space station in as many days. The Expedition 61 crew welcomed SpaceX’s cargo Dragon spacecraft early Sunday morning.

Image above: Dec. 9, 2019: International Space Station Configuration. Five spaceships are parked at the space station including the SpaceX Dragon space freighter, the Northrop Grumman Cygnus resupply ship and Russia’s Progress 74 resupply ship and Soyuz MS-13 and MS-15 crew ships. Image Credit: NASA TV.

The International Space Station is a stepping stone for NASA’s Artemis program that will land the first woman and next man on the Moon. As the only place for conducting long-duration research on how living in microgravity affects living organisms as well as testing technologies to allow humans to work at the Moon, the space station serves as a unique asset in the effort establish a sustainable presence at the Moon and prepare for missions to Mars.

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2019 December 9 Looking Sideways from the Parker Solar Probe...

2019 December 9

Looking Sideways from the Parker Solar Probe
Video Credit: NASA, JHUAPL, Naval Research Lab, Parker Solar Probe

Explanation: Everybody sees the Sun. Nobody’s been there. Starting in 2018 though, NASA launched the robotic Parker Solar Probe (PSP) to investigate regions near to the Sun for the first time. The PSP’s looping orbit brings it yet closer to the Sun each time around – every few months. The featured time-lapse video shows the view looking sideways from behind PSP’s Sun shield during its first approach to the Sun a year ago – to about half the orbit of Mercury. The PSP’s Wide Field Imager for Solar Probe (WISPR) cameras took the images over nine days, but they are digitally compressed here into about 14 seconds. The waving solar corona is visible on the far left, with stars, planets, and even the central band of our Milky Way Galaxy streaming by in the background as the PSP orbits the Sun. PSP has found the solar neighborhood to be surprisingly complex and to include switchbacks – times when the Sun’s magnetic field briefly reverses itself. The Sun is not only Earth’s dominant energy source, its variable solar wind compresses Earth’s atmosphere, triggers auroras, affects power grids, and can even damage orbiting communication satellites.

∞ Source: apod.nasa.gov/apod/ap191209.html

* This article was originally published here

Leahill Roman Turret (Turret 51b), Hadrian’s Wall, Brampton, 8.12.19.

Leahill Roman Turret (Turret 51b), Hadrian’s Wall, Brampton, 8.12.19.

* This article was originally published here

Banks East Roman Turret (Turret 52a), Hadrian’s Wall, Brampton, 8.12.19.Today I took a tour of...

Banks East Roman Turret (Turret 52a), Hadrian’s Wall, Brampton, 8.12.19.

Today I took a tour of the lesser visited sites of Hadrian’s Wall; turrets, signal towers and earthworks.

* This article was originally published here

Pike Hill Signal Tower, Hadrian’s Wall, Brampton, 8.12.19.A Roman Signal Tower predating...

Pike Hill Signal Tower, Hadrian’s Wall, Brampton, 8.12.19.

A Roman Signal Tower predating Hadrian’s Wall.

* This article was originally published here


Соединение Юпитера  ♃  и  Сатурна  ♄   21 декабря 2020   16 : 30 по Гринвичу, 21 декабря 2020 года, состоится условное соединение Юпитера ♃ ...