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1st image snapped by iconic Webb telescope pushes limits of the 'laws of physics' – Livescience.com

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The James Webb Space Telescope (Webb) has released its first sharp image and it is a doozy — a spectacular view of a twinkling orange star that is focused with such sharpness that it pushes the limits of the laws of physics. 

The image shows that the telescope’s 18 separate mirrors are now accurately aligned and acting as one, and the photo is even better than scientists hoped it would be, NASA officials said in a statement.

The Webb team released the photograph of the Milky Way star, designated 2MASS J17554042+6551277 and located roughly 2,000 light-years away, Wednesday (March 16). It was taken with a red filter to maximize the visual contrast between the star and the blackness of space, while dozens of other stars and distant galaxies can be seen in the background.

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According to BBC News, the image shows that the optical systems of the new space telescope are now working better than the scientists and engineers had hoped.

“You not only see the star and the spikes from the diffraction of the star, but you see other stars in the field that are tightly focused, just like we expect, and all sorts of other interesting structure in the background,” Webb engineer Lee Feinberg told reporters at the NASA news conference Wednesday. “We’ve actually done very detailed analysis of the images we’re getting, and so far, what we’re finding is that the performance is as good [as], if not better than, our most optimistic prediction.”

The image is the result of the “fine phasing” stage of the mirror alignments, in which every optical parameter is checked to verify that the telescope can successfully gather light from distant objects, NASA said in the statement.  

Mirror alignment

Feinberg has led the project to align the space telescope’s 18 hexagonal beryllium mirrors so they function as one nearly hexagonal mirror with a diameter of 21.3 feet (6.5 meters). The design allowed the system of mirrors to be folded and fit inside a rocket fairing at launch — unlike Webb’s predecessor, the Hubble Space Telescope, which has just one main mirror that’s about 7.8 feet (2.4 m) across. 

One of the first photographs from Webb, released last month, showed 18 images of a single star in a hexagonal pattern — one from each separate mirror, which by then had been roughly aligned to point at the same location.

The new image shows the unfolded mirrors have been adjusted to within nanometers, resulting in a single image in sharp focus, scientists said at the news conference.

“We now have achieved what’s called ‘diffraction limited alignment’ of the telescope,” Marshall Perrin, Webb deputy scientist at the Space Telescope Science Institute in Baltimore, said at the news conference. “The images are focused together as finely as the laws of physics allow.” 

This new “selfie” was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of the sky. In this image, all of Webb’s 18 primary mirror segments are shown collecting light from the same star in unison. (Image credit: NASA/STScI)

When light goes through a lens, it forms a central image and then a circle of “diffraction rings” around it like a bullseye. The diffraction limit, which is based on the wavelength, the lens power and the distance from the object you’re measuring, tells you how close together two objects or features can be before a telescope with a perfect lens can no longer tell them apart.

And the latest test photograph is already better than Hubble could have produced.

“The engineering images that we see today are as sharp and as crisp as the images that Hubble can take but are at a wavelength of light that is totally invisible to Hubble,” said Jane Rigby, operations project scientist for Webb at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “So this is making the invisible universe snap into very, very sharp focus.”

Future photographs

The next stage of the project will be to refine the alignment and bring several of the space telescope’s instruments online, according to the NASA statement.

They include the Near-Infrared Spectrograph, which will examine the light spectra from distant objects to learn more about their physical properties, such as their temperature and chemical composition; the Mid-Infrared Instrument, which is both a camera and a spectrograph that captures images in wavelengths the eye can’t see; and the Near-Infrared Imager and Slitless Spectrograph, a very precise instrument that will look for and investigate orbiting exoplanets.

The next stage will take about six weeks and will be followed by a final alignment stage in which the Webb team will adjust any residual positioning errors in the mirror segments. 

The Webb team says it’s on track to complete work on the telescope’s entire optical system by early May, which will be followed by another  two months of instrument preparation; the space telescope could start producing its first full high-resolution imagery and science data in the summer, the statement said.

The $10 billion James Webb Space Telescope is a collaboration among NASA, the European Space Agency and the Canadian Space Agency. It’s named after former NASA Administrator James E. Webb, who led the agency during the Mercury, Gemini and much of the Apollo space programs.

The space telescope launched on Dec. 25, 2021, after years of technical delays. It arrived in late January at the L2 Lagrange point of the sun-Earth system, about 930,000 miles (1.5 million kilometers) away, where gravity balances out centrifugal forces.

Scientists expect that Webb will be able to image distant objects up to 100 times too faint for the Hubble Space Telescope to see and that it will last 10 to 20 years, when the fuel for the thrusters that keep it in position will run out.

Originally published on Live Science.

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Peek-a-Boo Moon: Astronaut on Space Station Captures Spectacular Photos of the Lunar Eclipse – SciTechDaily

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ESA astronaut Samantha Cristoforetti captured pictures of the May 2022 lunar eclipse from the International Space Station.

On the evening of May 15, 2022, Earth passed between the Sun and the Moon blocking sunlight and casting a shadow on the lunar surface. ESA astronaut Samantha Cristoforetti witnessed this lunar eclipse from the International Space Station and captured it in a series of photographs.

During a lunar eclipse, Earth’s atmosphere scatters sunlight. The blue light from the Sun scatters away, and longer-wavelength red, orange, and yellow light pass through, turning our Moon red.

Lunar Eclipse From International Space Station 1

An image of a lunar eclipse as seen from the International Space Station. Credit: ESA-S.Cristoforetti

In these images, the Moon appears to play hide and seek with one of the International Space Station’s solar panels:

Lunar Eclipse From International Space Station 4

A partially eclipsed Moon playing hide and seek with the solar panel of the International Space Station. Credit: ESA-S.Cristoforetti

Lunar Eclipse From International Space Station 3

A partially eclipsed Moon playing hide and seek with the solar panel of the International Space Station. Credit: ESA-S.Cristoforetti

Lunar Eclipse From International Space Station 2

A partially eclipsed Moon playing hide and seek with the solar panel of the International Space Station. Credit: ESA-S.Cristoforetti

Samantha is living and working aboard the Space Station for her second mission, ‘Minerva’. Learn more about Samantha and the Minerva mission.

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African scientists and technology could drive future black hole discoveries – The Conversation Africa

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Astronomers have revealed the first image of the black hole at the centre of our galaxy, the Milky Way. The image was produced by the Event Horizon Telescope (EHT) Collaboration, an international team made up of over 300 scientists on five continents – including Africa.

Black holes were predicted by Albert Einstein’s General Theory of Relativity over a century ago. They are regions of space so dense that nothing, including light, can escape. Their boundary is known as the event horizon, which marks the point of no return. That’s just one of the reasons these objects are hidden from our eyes. The other is that they are exceedingly small, when placed in their cosmic context. If our Milky Way galaxy were the size of a soccer field, its black hole event horizon would be a million times smaller than a pin prick at centrefield.

How, then, can one photograph them? Our team did so by capturing light from the hot swirling gas in the immediate vicinity of the black hole. This light, with a wavelength of 1 millimetre, is recorded by a global network of antennas that form a single, Earth-sized virtual telescope.

The light looks rather like a ring, a characteristic signature that is the direct consequence of two key processes. First, the black hole is so dense that it bends the path of light near it. Second, it captures light that strays too close to the event horizon. The combined effect produces a so-called black hole shadow – a brightened ring surrounding a distinct deficit of light centred on the black hole. In the case of our Milky Way black hole, this ring has the apparent size of a doughnut on the moon, requiring an extraordinary engineering effort to bring it into focus.




Read more:
How we captured first image of the supermassive black hole at centre of the Milky Way


The unveiling of an image of our black hole, Sagittarius A*, is not just a massive moment for science. It could also be an important catalyst for diversifying African astrophysics research using existing strengths. We were the only two of more than 300 EHT team members based on the African continent. The continent doesn’t host any EHT telescopes – we were brought on board because of expertise we’ve developed in preparation for the world’s largest radio telescope, the Square Kilometre Array (SKA), to be co-hosted by South Africa and Australia.

Why the image is important

This is not the first time a black hole image has captured people’s attention. We were also members of the team that captured the first ever image of a black hole in 2019 (this one is at the centre of a different galaxy, Messier 87, which is 55 million light years away). It has been estimated that more than 4.5 billion people saw that image. Sagittarius A* has also dominated headlines and captured people’s imaginations.

But there’s more to this result than just an incredible image. A plethora of rich scientific results has been described in ten publications by the team. Here are three of our primary highlights.

First, the image is a remarkable validation of Einstein’s General Theory of Relativity. The EHT has now imaged two black holes with masses that differ by a factor of over 1000. Despite the dramatic difference in mass, the measured size and shape are consistent with theoretical predictions.

Second, we have now imaged black holes with very different environments. A wealth of prior research over the past two or three decades shows strong empirical evidence that galaxies and their black holes co-evolve over cosmic time, despite their completely disparate sizes. By zooming into the event horizon of black holes in giant galaxies like M87, as well as more typical galaxies like our own Milky Way, we learn more about how this seemingly implausible relationship between the black hole and its host galaxy plays out.

Third, the image provides us with new insights on the central black hole in our own galactic home. It is the nearest such beast to Earth, so it provides a unique laboratory to understand this interplay – not unlike scrutinising a tree in your own garden to better understand the forests on the distant horizon.

Southern Africa’s geographic advantage

We are proud to be part of the team that produced the first black hole images. In future, we believe South Africa, and the African continent more broadly (including a joint Dutch-Namibian initiative), could play a critical role in making the first black hole movies.




Read more:
Combined power of two telescopes is helping crack the mystery of eerie rings in the sky


As has been the case with the country’s key role in paleoanthropology, there are contributions to global astronomy that can only be made from South African soil. Sagittarius A* lies in the southern sky, passing directly above South Africa. That is a major reason why this image of the Milky Way’s centre, taken by the MeerKAT (a precursor to the SKA) is the best there is.

The MeerKAT Galactic Centre image (top). Predicted snapshot imaging performance (bottom middle), based on a simulated black hole movie (bottom left), using an African-enhanced EHT array (bottom right).
Heywood et al. (2022) / SARAO, M. Johnson (Harvard & Smithsonian)

South Africa also has well-established infrastructure at its astronomical sites, which are protected by legislation. And it has world-class engineers at the forefront of their craft. This makes for low-cost, high-performance telescopes delivered on time and to budget.

New technology is also on our side: a cutting-edge simultaneous multi-frequency receiver design, pioneered by our Korean colleagues, means that EHT sites no longer need to be the most pristine, high-altitude locations on Earth.

All the elements are in place for a dramatic increase in the number of young Africans who participate in this new era of black hole imaging and precision tests of gravity. In the coming years, we hope to be writing about findings that couldn’t have been made without technology on South African soil, as well as African scientists leading high-impact, high-visibility EHT science in synergy with our multi-wavelength astronomy and high-energy astrophysics programmes.

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150,000-Year-Old Human Tooth Is Rare Evidence of the Extinct Denisovans – Gizmodo

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The suspected Denisovan molar.
Photo: F. Demeter et al., 2022

Paleontologists in Laos have uncovered an ancient molar that likely belonged to a young Denisovan girl. The discovery is a big deal, as the Laotian cave in which the molar was found is now one of only three spots known to host these enigmatic humans.

In addition to Siberia and the Tibetan Plateau, we can now add Laos to the achingly short list of places that have yielded fossils of an elusive human species known as the Denisovans. A team of paleontologists found the suspected Denisovan molar at the Tam Ngu Hao 2 cave in the Annamite Mountains of Laos. The molar dates to the middle Pleistocene, and it’s the first Denisovan fossil ever to be found in southeast Asia. A paper detailing this discovery is published today in Nature Communications.

Laura Shackelford, an anthropologist from the University of Illinois at Urbana-Champaign and a co-author of the new study, was excited to learn that Denisovans, like their Neanderthal cousins, inhabited a variety of environments, some of them extreme.

The entrance to Tam Ngu Hao 2 cave, also known as Cobra Cave.
The entrance to Tam Ngu Hao 2 cave, also known as Cobra Cave.
Photo: F. Demeter et al., 2022

“Although we only have a few fossils representing the Denisovans, this new fossil from Laos demonstrates that much like modern humans, Denisovans were widespread and they were highly adaptable,” Shackelford explained in an email. “They lived in the cold arctic temperatures of Siberia, in the cold, [oxygen poor] environment of the Tibetan Plateau, and now we know they were also living in the tropics of southeast Asia.”

What’s more, the new discovery “further attests” that southeast Asia was “a hotspot of diversity for the genus Homo” during the middle to late Pleistocene, as the scientists write in their study. So in addition to Denisovans, this part of the world was once home to H. erectus, Neanderthals, H. floresiensis, H. luzonensis, and H. sapiens.

That a Denisovan fossil was found in Laos is not a huge surprise. Traces of Denisovan DNA have been detected within the genomes of modern southeast Asian and Oceanian populations. The Ayta Magbukun—a Philippine ethnic group—have retained approximately 5% of their Denisovan ancestry, the highest of any human group in the world. Denisovans branched off from Neanderthals at some point between 200,000 and 390,000 years ago. They eventually went extinct, but not before interbreeding with modern humans. The Laotian molar is just the 10th Denisovan fossil to be found and the first outside of Siberia and Tibet.

The Annamite Mountains contain an abundance of limestone caves. Each year, Shackelford and her colleagues dispatch geologists to the area in hopes of finding spots worthy of further paleontological investigation.

“In 2018, our geologists spent the morning surveying and returned to the site before lunch with their pockets full of sediment samples that they had collected from a potential new site, what we now know as Tam Ngu Hao 2 or Cobra Cave,” Shackelford told me. “In these first samples, among fragments of fossil animal teeth, we found the tooth.”

By dating the sediment in which the molar was found, the team aged the fossil to between 164,000 and 131,000 years old. A protein analysis of the tooth’s enamel identified the fossil as belonging to a member of the Homo genus, but this test couldn’t pin down the exact species.

Study co-author Fabrice Demeter analyzing the molar.
Study co-author Fabrice Demeter analyzing the molar.
Photo: F. Demeter et al., 2022

“We do know that this is the tooth of a girl who died when she was between about 4 to 8 years old,” said Shackelford. “Since this tooth comes from a child, we are currently doing additional analyses of tooth growth and development.”

Clément Zanolli, an expert on the evolution of human teeth and a co-author of the new study, said the identification of the Denisovan molar arose from multiple lines of morphological evidence. The Laotian molar, he told me, bears a resemblance to teeth found on the partial Denisovan mandible from Tibet, including large tooth dimensions and various distinguishing features that separate it from other Homo species known to inhabit southeast Asia, including Neanderthals and modern humans.

“Among the human groups previously cited, the molar from Laos is closest to Neanderthals, and we know from paleogenetics that Denisovans were a sister group of Neanderthals, meaning that they were closely related and shared morphological features,” Zanolli, who works at the University of Bordeaux, explained in an email. “For these reasons, the most parsimonious hypothesis is that the tooth that we found in Laos belongs to a Denisovan individual.”

It’s not impossible that the molar belonged to a Neanderthal, but if that’s the case, that “would make it the south-eastern-most Neanderthal fossil ever discovered,” according to the paper.

“We are confident it is Denisovan,” Fabrice Demeter, a paleoanthropologist at the University of Copenhagen and a co-author of the study, told me in an email. But to “further confirm our results if needed, genetic analyses would be useful,” he said. Unfortunately, however, “DNA tends to fragment more quickly and intensely in tropical environments,” and it’s for this reason that “no ancient DNA from any Pleistocene human has been sequenced so far,” he added.

The new fossil is important because it affirms something already hinted at by the genetic data—that Denisovans once inhabited a wide area of southeast Asia. What’s more, it “confirms that Denisovans were present in this region and could have met with Late Pleistocene modern humans,” according to Zanolli. And lastly, it shows that Denisovans could live in both cold, high-altitude environments and the tropical forests of southeast Asia.

The Denisovans appear to have been an adaptable group. But that just makes their sudden disappearance some 50,000 years ago all the more mysterious.

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