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Human origins: 'Little Foot' fossil's big journey out of Africa – BBC News

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Diamond Light Source

A priceless fossil was briefly brought to a UK research centre in complete secrecy two years ago, in an operation that had more than a touch of the spy novel about it.

The specimen was transported across South Africa with an armed guard, treated like an incognito VIP on an international flight, and then whisked slickly to the Diamond X-ray Light Source just south of Oxford.

It was at the British research facility that scientists were able to see some microscopic details in the ancient remains that could help unravel key clues to the origins of modern humans.

Details of the operation have been made public only now, as the first results from the X-ray investigations have been shared with the wider research community.

“It was immensely nerve-wracking,” palaeoanthropologist Dominic Stratford recalls of the cloak-and-dagger mission, the first time any part of a prehistoric individual has been allowed out of South Africa.

Not only are the remains beyond value, after three million or more years embedded in sediments in the floor of a South African cave, they are immensely fragile.

What Prof Stratford had transported was the skull of “Little Foot”, the most complete Australopithecine fossil ever recovered. And given the Australopithecines’ position on the evolutionary road to modern humans, this makes Little Foot extra special.

Skull in the beamline

Diamond Light Source

Accompanying Prof Stratford and the skull was Ronald Clarke, the Witwatersrand University professor who led Little Foot’s more-than-20-year excavation from the Sterkfontein Caves just outside Johannesburg.

Also in the party was Dr Amélie Beaudet, keen to use Diamond’s powerful X-rays to peer inside the delicate object while doing no damage.

“With the X-rays, we found we could see tiny structures like the vasculature system, where there had been blood vessels inside Little Foot’s bones, which normally would require physically slicing up a specimen,” she told BBC News.

Prof Ian Tattersall, curator emeritus of human origins at the American Museum of Natural History in New York, is bowled over by the details revealed in the first scholarly paper to come out of the Diamond study.

“It is wonderful to have confirmation that micromorphology at this resolution can be recovered from a hominid this old,” he said.

Team discusses skull

Diamond Light Source

From the Natural History Museum in London, Dr Louise Humphrey, a specialist in human origins and bioarchaeology not involved in the study, affirms the power of “this type of non-invasive investigation of microscopic structures… to reconstruct different aspects of an individual’s life history from birth to death”.

As an example, she highlights details in the tooth enamel revealed by the X-rays.

“Tooth enamel is not renewed during life,” Dr Humphrey explains, “so it preserves a record of an individual’s environment, diet and health during the first few years of life when the tooth crowns are developing.”

Disrupted growth patterns revealed by the high-resolution images indicate “that [Little Foot] experienced at least two events that interrupted development during early life”, she says.

Dr Beaudet told the BBC these tooth defects really stood out. “Dietary deficiency or nutritional stress” are blamed in the paper, though in an interview for BBC Radio 4’s Inside Science programme, she accepted “we don’t know if Little Foot was sick at some time, or if she couldn’t find enough food”.

Diamond viewed from the air

Diamond Light Source

Dr Beaudet says they are also planning to measure a layer of material at the root of the teeth called cementum, which could indicate Little Foot’s age when she died. It’s thought the creature fell through an opening in the floor of the cave where she was found.

The sheer amount of data the team managed to collect at Diamond, seven terabytes (140 Blu-ray discs), has been a challenge. Generating it was, too.

The skull, not much smaller than a modern human’s, was far larger than they had been accustomed to examining at the synchrotron’s “I12” imaging beamline.

The South African researchers had first sent a plastercast of the specimen, explained Thomas Connelley, the principal scientist on the beamline.

This meant the team could rehearse how best to mount the real object safely. And it was too large to be imaged all at once, so that new techniques had to be developed to knit together a patchwork of stills to create a complete 3D rendering – all the while conscious of the skull’s importance in human prehistory.

“Only two people were allowed to handle the fossil,” he reported. “Prof Clarke and Dominic Stratford.”

He added: “None of us were allowed to touch it – with very good reason! Little Foot is probably the oldest and best-preserved fossils of this type.

“This was a very special experiment,” Dr Connelley admitted. “It was actually quite emotional to think that we were studying one of our very early ancestors – for everyone I think, certainly for me.”

Dominic Stratford confesses to a little emotion, too.

“It was a fantastic moment when we were all ‘hutched’ together in the beamline control room – it’s always difficult to imagine what’s preserved, so when we finally started to see some images, it was completely remarkable,” he recalled.

Schematic of Diamond

Dr Beaudet, now based at Cambridge University after several years on Prof Clarke’s team at Witwatersrand, says it is the imprint of the brain on the inside of the skull that will be most interesting for what it reveals of the early development of human intelligence.

Already the team has identified the traces of blood vessels in the inner skull that are similar to ones found in modern humans.

“The main hypothesis is that in modern humans, these vessels are involved in thermoregulation – preventing our brain from becoming too hot. With Little Foot, the brain was the same size as a chimpanzee’s. It was only later in evolution that the brain grew dramatically. But at some point, something had to change in the vascular system, too. So the fact that we can see these vessels in Little Foot is quite promising,” she said.

The problem is that at the moment, the team has no fossil comparisons – no study this detailed has been attempted before on ancient human remains.

For palaeoanthropologist Ian Tattersall, this is what makes the preliminary data from Diamond so tantalising.

“While there are no amazing revelations here, this study opens large vistas for the future,” he said. “And it is especially significant in demonstrating that micromorphology can be recovered from truly ancient hominid fossils without having to resort to destructive techniques. That is truly an exciting prospect.”

There is much more work to be done on the skull scans already obtained, according to Dr Beaudet, but she is looking forward to examining the leg and arm bones, hands and feet of Little Foot, for what they will reveal of our ancestors’ transition from tree-living to scurrying around on the ground.

The success with these first experiments reassures Prof Stratford.

“One of the blessings and curses of Little Foot is that we have these amazingly well-preserved, complete, single bones, which is almost unheard of. Fragments are easy to move around and to scan. But if you have a complete leg bone, or upper-arm and shoulder blade – that becomes a real challenge,” he said.

“We have seen the potential to do this at Diamond. And that means we could reconstruct how Little Foot lived on the landscape, how she moved around, what kind of stresses she was putting the bones under. And we could fit that into the big picture of human evolution at the time.”

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Humans actually hunted large animals and ate mostly meat for 2 millions years: study – CTV News

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TORONTO —
Despite a widespread belief that humans owe their evolution to the dietary flexibility in eating both meat and vegetables, researchers in Israel suggest that early humans were actually apex predators who hunted large animals for two million years before they sought vegetables to supplement their diet.

In a study recently published in the American Journal of Physical Anthropology, academics from Tel Aviv University in Israel and the University of Minho in Portugal examined modern biology to determine if stone-age humans were specialized carnivores or generalist omnivores.

“So far, attempts to reconstruct the diet of Stone-Age humans were mostly based on comparisons to 20th century hunter-gatherer societies,” one of the study’s authors, Miki Ben-Dor, a researcher at Tel Aviv University, said in a press release.

“This comparison is futile, however, because two million years ago hunter-gatherer societies could hunt and consume elephants and other large animals – while today’s hunter gatherers do not have access to such bounty.”

Instead, the researchers looked at approximately 400 previous scientific studies on human anatomy and physiology as well as archeological evidence from the Pleistocene period, or “Ice Age” period, which began about 2.6 million years ago, and lasted until 11,700 years ago.

“We decided to use other methods to reconstruct the diet of Stone-Age humans: to examine the memory preserved in our own bodies, our metabolism, genetics and physical build,” Ben-Dor said.

“Human behaviour changes rapidly, but evolution is slow. The body remembers.”

They discovered 25 lines of evidence from the studied papers on human biology that seem to show that earlier Homo sapiens were apex predators at the top of the food chain.

For example, the academics explained that humans have a high acidity in their stomachs when compared to omnivores or even other predators, which is important for consuming animal products.

“Strong acidity provides protection from harmful bacteria found in meat, and prehistoric humans, hunting large animals whose meat sufficed for days or even weeks, often consumed old meat containing large quantities of bacteria, and thus needed to maintain a high level of acidity,” Ben-Dor said.

Another piece of evidence, according to the study, is the structure of human fat cells.

“In the bodies of omnivores, fat is stored in a relatively small number of large fat cells, while in predators, including humans, it’s the other way around: we have a much larger number of smaller fat cells,” Ben-Dor said.

HUNTING EXPERTS

In addition to the evidence they collected by studying human biology, the researchers said archeological evidence from the Pleistocene period supports their theory.

In one example, the study’s authors examined stable isotopes in the bones of prehistoric humans as well as their hunting practices and concluded these early humans specialized in hunting large and medium-sized animals with high fat content.

“Comparing humans to large social predators of today, all of whom hunt large animals and obtain more than 70% of their energy from animal sources, reinforced the conclusion that humans specialized in hunting large animals and were in fact hypercarnivores,” the academics noted.

Ben-Dor said Stone-Age humans’ expertise in hunting large animals played a major role in the extinction of certain large animals, such as mammoths, mastodons, and giant sloths.

“Most probably, like in current-day predators, hunting itself was a focal human activity throughout most of human evolution. Other archeological evidence – like the fact that specialized tools for obtaining and processing vegetable foods only appeared in the later stages of human evolution – also supports the centrality of large animals in the human diet, throughout most of human history,” he said.

This is not to say, however, that humans during this period didn’t eat any plants. Ben-Dor said they also consumed plants, but they weren’t a major component of their diet until the end of the era when the decline of animal food sources led humans to increase their vegetable intake.

Eventually, the researchers said humans had no choice but to domesticate both plants and animals and become farmers.

Ran Barkai, one of the study’s authors and a professor at Tel Aviv University, said their findings have modern-day implications.

“For many people today, the Paleolithic diet is a critical issue, not only with regard to the past, but also concerning the present and future. It is hard to convince a devout vegetarian that his/her ancestors were not vegetarians, and people tend to confuse personal beliefs with scientific reality,” he said. 

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Marimaca Copper: First Drill Hole Intersects Broad Zone of Sulphide Copper Mineralization at Marimaca – Junior Mining Network

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VANCOUVER, British Columbia, April 07, 2021 (GLOBE NEWSWIRE) — Marimaca Copper Corp. (“Marimaca Copper” or the “Company”) (TSX: MARI) is pleased to announce the assay results of the first drill hole of a five-hole program targeting extensions of sulphide mineralization below the Company’s flagship Marimaca Oxide Deposit (“MOD”). Drilling encountered a broad zone of chalcopyrite and minor chalcocite, indicating potential for economic sulphide mineralization.

Highlights

  • Drill hole MAR-125 intersected 116m (expected approximate true width) at an average grade of 0.51% CuT from 162m, including two higher grade zones of:
    • 20m with an average grade of 0.77% CuT from 162m; and
    • 42m with an average grade of 0.92% CuT from 236m.
  • Intersection represents a significantly broader zone of mineralization than anticipated from earlier, nearby, sulphide drilling intersections
  • First drill hole of an initial five-hole campaign to test for extensions of mineralization at depth
    • First hole designed to extend mineralization closer to sulphide zones identified in historical drilling
    • Remaining four holes designed to test the limits of mineralization with step outs of approximately 300m at depth and between 400m and 700m along strike to the north and south of the first hole
  • Sulphide drilling to be completed shortly, with assay results on remaining holes expected by the end of April 2021
  • In response to escalating COVID situation in Chile, the Company has initiated a break in drilling which is not expected to impact the original target of testing all identified targets by the end of 1H 2021.

Sergio Rivera, VP Exploration of Marimaca Copper, commented:

“The results of the first hole of this initial campaign are extremely pleasing, exceeding both the widths and grades we had projected for this zone based on earlier drilling completed nearby. The broad intercept of chalcopyrite mineralization shows good continuity downhole, with potentially economic grades, especially at the bottom of the intercept.

“The drilling has also provided additional geological information, which we are using to refine our understanding of the controls of mineralization and to inform future drillhole locations, targeting mineralized extensions at depth and along strike.

“The next four holes are significant step outs from the known mineralized zones outside of the Mineral Resource Estimate area and are designed to test the limits of the mineralized body, both at depth and along strike. The second hole will be collared approximately 350m to the east of MAR-125, targeting mineralization up to 300m below the current deepest mineralization. The third, fourth and fifth holes will be located between 400m and 700m to the north and south of MAR-125, aiming to test for extensions along strike.

“This first hole has provided encouragement that there is potential for economically interesting sulphide mineralization at Marimaca, while the next four drill holes are designed to better delineate the tonnage potential of this.”

Discussion of Campaign Objectives and Results

The current five-hole drilling campaign at the Marimaca Copper Project is designed to test for extensions to mineralization below the MOD. Based on the structural controls of the mineralization, the results of previous geophysical campaigns and earlier drilling, which extended beyond the current Mineral Resource Estimate (“MRE”) area, the Company believes there is the potential for extensions of the mineralized body at depth across the full strike length of the MOD. All drill holes will be drilled at an azimuth of 270o and at -60o, roughly perpendicular to the north-south striking, easterly dipping mineralizing structures. Intercepts should, therefore, be relatively close to the true width of the mineralization.

The first drill hole (MAR-125) encountered a broad zone of dominantly chalcopyrite mineralization with some pyrite and minor chalcocite over a down hole width (expected to be equivalent to approximate true width) of 116m with an average grade of 0.51% CuT. This includes two zones of higher-grade mineralization including 20m with an average grade of 0.77% CuT and 42m with an average grade of 0.92% CuT at the end of the mineralized intercept. The hole was collared to test mineralization approximately 100m to the east of the earlier hole ATR-82, which intersected 44m of sulphide copper mineralization with an average grade of 1.05% CuT, and 200m and 300m east of holes ATR-93 and ATR-94 respectively, which both intersected mineralization with true widths of around 40m with average grades above 1.0% CuT. MAR-125 has demonstrated an extension to this higher-grade mineralization and provides further areas to target for follow up drilling.

MAR-125 is located in the center of the current MRE area, proximal to a zone of relatively high-grade sulphide mineralization intercepted in several drill holes over widths of between 30m and 50m. The remaining four drill holes have been located to test the limits of the mineralization by stepping out significantly at depth and along strike beyond the current MRE area. The collar of the second hole, MAS-03, is located approximately 100m to the south and 350m to the east of MAR-125 and is aimed to intersect mineralization approximately 300m below MAR-125. MAS-02 and MAS-04, located approximately 400m and 700m, respectively, south of MAR-125, and are planned as significant step outs along strike, targeting the conductivity high noted in the IP survey completed across the MOD

Figure 2

Sampling and Assay Protocol

True widths cannot be determined with the information available at this time. Marimaca Copper RC holes were sampled on a 2-metre continuous basis, with dry samples riffle split on site and one quarter sent to the Andes Analytical Assay preparation laboratory in Calama and the pulps then sent to the same company laboratory in Santiago for assaying. A second quarter was stored on site for reference. Samples were prepared using the following standard protocol: drying; crushing to better than 85% passing -10#; homogenizing; splitting; pulverizing a 500-700g subsample to 95% passing -150#; and a 125g split of this sent for assaying. All samples were assayed for CuT (total copper), CuS (acid soluble copper) by AAS. A full QA/QC program, involving insertion of appropriate blanks, standards and duplicates was employed with acceptable results. Pulps and sample rejects are stored by Marimaca Copper for future reference.

Qualified Person

The technical information in this news release, including the information that relates to geology, drilling and mineralization was prepared under the supervision of, or has been reviewed by Sergio Rivera, Vice President of Exploration, Marimaca Copper Corp, a geologist with more than 36 years of experience and a member of the Colegio de Geólogos de Chile and of the Institute of Mining Engineers of Chile, and who is the Qualified Person for the purposes of NI 43-101 responsible for the design and execution of the drilling program.

Mr. Rivera confirms that he has visited the Marimaca Project on numerous occasions, is responsible for the information contained in this news release and consents to its publication.

Contact Information
For further information please visit www.marimaca.com or contact:

Tavistock
+44 (0) 207 920 3150
Jos Simson/Emily Moss 
This email address is being protected from spambots. You need JavaScript enabled to view it. 

Forward Looking Statements

This news release includes certain “forward-looking statements” under applicable Canadian securities legislation. These statements relate to future events or the Company’s future performance, business prospects or opportunities. Forward-looking statements include, but are not limited to, the impact of a rebranding of the Company, the future development and exploration potential of the Marimaca Project. Actual future results may differ materially. There can be no assurance that such statements will prove to be accurate, and actual results and future events could differ materially from those anticipated in such statements. Forward-looking statements reflect the beliefs, opinions and projections on the date the statements are made and are based upon a number of assumptions and estimates that, while considered reasonable by Marimaca Copper, are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors, both known and unknown, could cause actual results, performance or achievements to be materially different from the results, performance or achievements that are or may be expressed or implied by such forward-looking statements and the parties have made assumptions and estimates based on or related to many of these factors. Such factors include, without limitation: risks related to share price and market conditions, the inherent risks involved in the mining, exploration and development of mineral properties, the uncertainties involved in interpreting drilling results and other geological data, fluctuating metal prices, the possibility of project delays or cost overruns or unanticipated excessive operating costs and expenses, uncertainties related to the necessity of financing, the availability of and costs of financing needed in the future as well as those factors disclosed in the Company’s documents filed from time to time with the securities regulators in the Provinces of British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador. Accordingly, readers should not place undue reliance on forward-looking statements. Marimaca Copper undertakes no obligation to update publicly or otherwise revise any forward-looking statements contained herein whether as a result of new information or future events or otherwise, except as may be required by law.


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Hubble Spots Double Quasars in Merging Galaxies – HubbleSite

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Research Box Title

NASA’s Hubble Space Telescope is “seeing double.” Peering back 10 billion years into the universe’s past, Hubble astronomers found a pair of quasars that are so close to each other they look like a single object in ground-based telescopic photos, but not in Hubble’s crisp view.

The researchers believe the quasars are very close to each other because they reside in the cores of two merging galaxies. The team went on to win the “daily double” by finding yet another quasar pair in another colliding galaxy duo.

A quasar is a brilliant beacon of intense light from the center of a distant galaxy that can outshine the entire galaxy. It is powered by a supermassive black hole voraciously feeding on inflating matter, unleashing a torrent of radiation.

“We estimate that in the distant universe, for every 1,000 quasars, there is one double quasar. So finding these double quasars is like finding a needle in a haystack,” said lead researcher Yue Shen of the University of Illinois at Urbana-Champaign.

The discovery of these four quasars offers a new way to probe collisions among galaxies and the merging of supermassive black holes in the early universe, researchers say.

Quasars are scattered all across the sky and were most abundant 10 billion years ago. There were a lot of galaxy mergers back then feeding the black holes. Therefore, astronomers theorize there should have been many dual quasars during that time.

“This truly is the first sample of dual quasars at the peak epoch of galaxy formation with which we can use to probe ideas about how supermassive black holes come together to eventually form a binary,” said research team member Nadia Zakamska of Johns Hopkins University in Baltimore, Maryland.

The team’s results appeared in the April 1 online issue of the journal Nature Astronomy.

Shen and Zakamska are members of a team that is using Hubble, the European Space Agency’s Gaia space observatory, and the Sloan Digital Sky Survey, as well as several ground-based telescopes, to compile a robust census of quasar pairs in the early universe.

The observations are important because a quasar’s role in galactic encounters plays a critical part in galaxy formation, the researchers say. As two close galaxies begin to distort each other gravitationally, their interaction funnels material into their respective black holes, igniting their quasars.

Over time, radiation from these high-intensity “light bulbs” launch powerful galactic winds, which sweep out most of the gas from the merging galaxies. Deprived of gas, star formation ceases, and the galaxies evolve into elliptical galaxies.

“Quasars make a profound impact on galaxy formation in the universe,” Zakamska said. “Finding dual quasars at this early epoch is important because we can now test our long-standing ideas of how black holes and their host galaxies evolve together.”

Astronomers have discovered more than 100 double quasars in merging galaxies so far. However, none of them is as old as the two double quasars in this study.

The Hubble images show that quasars within each pair are only about 10,000 light-years apart. By comparison, our Sun is 26,000 light-years from the supermassive black hole in the center of our galaxy.

The pairs of host galaxies will eventually merge, and then the quasars also will coalesce, resulting in an even more massive, single solitary black hole.

Finding them wasn’t easy. Hubble is the only telescope with vision sharp enough to peer back to the early universe and distinguish two close quasars that are so far away from Earth. However, Hubble’s sharp resolution alone isn’t good enough to find these dual light beacons.

Astronomers first needed to figure out where to point Hubble to study them. The challenge is that the sky is blanketed with a tapestry of ancient quasars that flared to life 10 billion years ago, only a tiny fraction of which are dual. It took an imaginative and innovative technique that required the help of the European Space Agency’s Gaia satellite and the ground-based Sloan Digital Sky Survey to compile a group of potential candidates for Hubble to observe.

Located at Apache Point Observatory in New Mexico, the Sloan telescope produces three-dimensional maps of objects throughout the sky. The team poured through the Sloan survey to identify the quasars to study more closely.

The researchers then enlisted the Gaia observatory to help pinpoint potential double-quasar candidates. Gaia measures the positions, distances, and motions of nearby celestial objects very precisely. But the team devised a new, innovative application for Gaia that could be used for exploring the distant universe. They used the observatory’s database to search for quasars that mimic the apparent motion of nearby stars. The quasars appear as single objects in the Gaia data. However, Gaia can pick up a subtle, unexpected “jiggle” in the apparent position of some of the quasars it observes.

The quasars aren’t moving through space in any measurable way, but instead their jiggle could be evidence of random fluctuations of light as each member of the quasar pair varies in brightness. Quasars flicker in brightness on timescales of days to months, depending on their black hole’s feeding schedule.

This alternating brightness between the quasar pair is similar to seeing a railroad crossing signal from a distance. As the lights on both sides of the stationary signal alternately flash, the sign gives the illusion of “jiggling.”

When the first four targets were observed with Hubble, its crisp vision revealed that two of the targets are two close pairs of quasars. The researchers said it was a “light bulb moment” that verified their plan of using Sloan, Gaia, and Hubble to hunt for the ancient, elusive double powerhouses.

Team member Xin Liu of the University of Illinois at Urbana-Champaign called the Hubble confirmation a “happy surprise.” She has long hunted for double quasars closer to Earth using different techniques with ground-based telescopes. “The new technique can not only discover dual quasars much further away, but it is much more efficient than the methods we’ve used before,” she said.

Their Nature Astronomy article is a “proof of concept that really demonstrates that our targeted search for dual quasars is very efficient,” said team member Hsiang-Chih Hwang, a graduate student at Johns Hopkins University and the principal investigator of the Hubble program. “It opens a new direction where we can accumulate a lot more interesting systems to follow up, which astronomers weren’t able to do with previous techniques or datasets.”

The team also obtained follow-up observations with the National Science Foundation NOIRLab’s Gemini telescopes. “Gemini’s spatially-resolved spectroscopy can unambiguously reject interlopers due to chance superpositions from unassociated star-quasar systems, where the foreground star is coincidentally aligned with the background quasar,” said team member Yu-Ching Chen, a graduate student at the University of Illinois at Urbana-Champaign.

Although the team is convinced of their result, they say there is a slight chance that the Hubble snapshots captured double images of the same quasar, an illusion caused by gravitational lensing. This phenomenon occurs when the gravity of a massive foreground galaxy splits and amplifies the light from the background quasar into two mirror images. However, the researchers think this scenario is highly unlikely because Hubble did not detect any foreground galaxies near the two quasar pairs.

Galactic mergers were more plentiful billions of years ago, but a few are still happening today. One example is NGC 6240, a nearby system of merging galaxies that has two and possibly even three supermassive black holes. An even closer galactic merger will occur in a few billion years when our Milky Way galaxy collides with neighboring Andromeda galaxy. The galactic tussle would likely feed the supermassive black holes in the core of each galaxy, igniting them as quasars.

Future telescopes may offer more insight into these merging systems. NASA’s James Webb Space Telescope, an infrared observatory scheduled to launch later this year, will probe the quasars’ host galaxies. Webb will show the signatures of galactic mergers, such as the distribution of starlight and the long streamers of gas pulled from the interacting galaxies.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

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