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Bloodsucking-fish fossils overturn once-popular theory about our evolution – CBC.ca

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Lampreys are boneless, blood-sucking snake-like fish considered to be “living fossils” that have barely changed since they first arose during the Paleozoic era, more than 100 million years before the first dinosaurs.  

Interestingly, since the 1800s, scientists have thought that the earliest ancestors of all vertebrates, including ourselves, resembled lampreys’ worm-like babies.

Now, recently discovered baby lamprey fossils have overturned that popular evolutionary theory, which some scientists were already starting to question, reports a Canadian-led study published in the latest issue of the journal Nature.

It turns out that baby lampreys from the Paleozoic era, which  had been “missing” from the fossil record until now, don’t look the way scientists had previously hypothesized — raising new questions about what our ancestors were really like.

Why scientists thought our ancestors were like baby lampreys

To be sure, adult lampreys seem like an unlikely candidate for what the progenitor of vertebrates might have looked like.

They’re alien-looking predators with a sucker-like mouth ringed with multiple rows of sharp teeth that they use to pierce the skin of their prey — usually other fish — and suck out their blood. One species, the sea lamprey, has devastated fisheries in the Great Lakes since invading them in the early 1900s via shipping canals. 

This is an adult sea lamprey, a species that has invaded the Great Lakes and devastated fisheries there by sucking the blood of other fish, often killing them in the process. Lampreys have no bones, only cartilage, so they didn’t fossilize well. (photo credit: T. Lawrence GLFC)

But lampreys aren’t born monsters. Their babies or larvae are tiny, blind, worm-like creatures called ammocoetes that burrow in the mud and slurp algae and rotting organic matter floating by.

They also have an uncanny resemblance to worm-like animals called lancelets  that don’t have a backbone, but do have many other characteristics of vertebrates, the group that includes fish, amphibians, reptiles, birds and mammals. That puts lancelets just on the other side of the border between vertebrates and invertebrates like worms, snails and insects.

This is the ammocoete or larva of a modern Pacific lamprey. It is a tiny, blind, filter-feeding worm-like animal that lacks the large eyes, sucker mouth and teeth of the adult. (Gregory Kovalchuk)

The lancelet Amphioxides is seen under the microscope. Lancelets are worm-like animals that don’t have a backbone, but share many other characteristics with vertebrates. Ammocoetes have a physical resemblance to lancelets. (D. Kucharski K. Kucharska/Shutterstock)

Biologists also believed that the larval or embryonic development of some animals was, in some ways, a look back through time at their evolution. For example, human embryos have a tail and gill-like structures around their necks.

All that led scientists to theorize about what the ancestor of all vertebrates — from fish to fowl to humans — might have looked like.

Tetsuto Miyashita, a research scientist at the Canadian Museum of Nature in Ottawa who led the new study, says that since the 19th century, when people looked at ammocoetes, “the common wisdom was that we were looking at… our distant ancestors in the face.”

Gap in the fossil record

It’s not a flattering thought, but it was a popular one up until several years ago..

That’s when researchers such as Margaret Docker, a professor in the department of biological sciences at the University of Manitoba, began to question the evidence.

For one thing, scientists hadn’t found ammocoete fossils dating back earlier than 125 million years ago, even though the earliest lamprey fossils known are 360 million years old. 

So, did early lampreys even have an ammocoete stage?

“There were just none of the earlier stages apparent,” said Docker, who wasn’t involved in the new study. She published a paper with two other scientists in 2018 suggesting that early lampreys either didn’t have a larval stage or only had a very short one, but noted they weren’t the first to be thinking of that.

“For the longest time, I sort of just came to the conclusion that we would never really know for sure.”

Tetsuto Miyashita (right) stands with researcher Rob Gess in 2016 atop the shale deposit in Makhanda, South Africa that has yielded fossils of the 360 million-year-old Priscomyzon lamprey. Many other invertebrate and plant fossils have been found at this site. (Tetsuto Miyashita)

That’s because lampreys don’t fossilize well, as they have no bones, only cartilage. They only form compressed fossils under very specific conditions, similar to those that preserved soft-bodied ancient creatures in Canada’s Burgess Shale, said Philippe Janvier, emeritus director of research at the French Centre National de la Recherche Scientific (CNRS) in an email.

“Such fossils have long been regarded as barely more informative than a squashed slug on a highway,” said Janvier, who co-authored the 2018 paper with Docker. It was hard to tell whether any of them were ammocoetes or juveniles in the middle of metamorphosing into adults.

How the gap was filled

Still, Miyashita was determined to have a closer look at that fossil evidence to see if the theory about ancient ammocoetes was true, so he went looking where the oldest known lamprey fossil had been found: a site in South Africa called Waterloo Farm.

Back in the Paleozoic, South Africa was located at the South Pole, but it was much warmer and wasn’t always iced over. At that time, Waterloo Farm was a coastal lagoon teeming with fish and invertebrates, which made up most of the animals on Earth at that time, when the ancestors of modern amphibians were just starting to take their first steps out of the water and onto land.

Miyashita got in touch with the local expert there, Robert Gess, a paleontologist and research associate at the Albany Museum and Rhodes University in Makhanda, South Africa. Gess had rescued 100 tonnes of shale that contained thousands of fossil specimens at Waterloo Farm before the construction of a local road.

Fossil of the hatchling of Priscomyzon, from the Paleozoic era around 360 million years ago. The hatchling is already equipped with large eyes and toothed sucker, which in modern lampreys only develop in adults. (The Canadian 25-cent coin offers a size comparison for the tiny fossil). (Tetsuto Miyashita/Canadian Museum of Nature)

Miyashita wanted to see if there were very small lampreys or ammocoetes in the rocks. 

Gess managed to spot seven, all smaller than the smallest ones he had previously found, Miyashita recalled — the tiniest of them “the size of your little fingernail.”

Despite that, the researchers could see that it was clearly a lamprey, with huge eyes for spotting prey and a sucker mouth with sharp teeth like adult lampreys today. 

But it wasn’t an adult. Upon closer inspection, that fossil had a little bulge on its belly. 

With excitement, the researchers realized that it was a yolk, which many fish carry with them to feed them when they first hatch, Miyashita said: “This baby fossil lamprey just hatched out of the egg.”

An artist’s reconstruction shows the life stages of the fossil lamprey Priscomyzon riniensis. It lived around 360 million years ago in a coastal lagoon in what is now South Africa. Clockwise from right: A tiny, yolk-sac carrying hatchling with its large eyes; a juvenile; and an adult showing its toothed sucker. (Kristen Tietjen)

Janvier, who wasn’t involved in the study, agreed that the bulge was clearly a yolk sac, similar to those found in many fossil hatchlings of other fish.

When Miyashita went through museum collections of other ancient lamprey fossils, he found hatchlings of other species that also looked like mini-adults.

It was clear evidence that ancient lampreys didn’t have a worm-like larval stage. While the adults might be “living fossils,” the ammocoetes evolved later.

Docker estimates it  happened around 300 million years ago, since modern lamprey species all have an ammocoete stage, suggesting their common ancestor from that time already had the trait. That period was when many insects and amphibians also developed very different juvenile and adult stages in different environments, such as water and land, with a metamorphosis in between.

At that time, plants had colonized the land, creating and stabilizing soils with their roots, making freshwater environments less prone to wild fluctuations and raging floods, and therefore more habitable.

But it was still an environment with few predators — one where tiny baby animals could safely grow. 

Miyashita searched the collections of other museums and found other ancient lamprey hatchlings with similar features. This is a Pipiscius zangerli hatchling that lived 309 million years ago, from the Mazon Creek fossil beds in Illinois, U.S.A. It also had large eyes, a toothed sucker, and a yolk sac showing it had just hatched. (Tetsuto Miyashita)

Miyashita said developing a larval stage capable of colonizing those safe freshwater environments probably “was the key for the survival of modern lamprey lineages.”

What it means for the story of our evolution

Miyashita said the fossil discovery has big implications for theories about the evolution of vertebrates. Clearly, ammocoetes don’t look the way they do because of a resemblance to the ancestor of all vertebrates, as previously thought.

“It’s not exactly often that just a single set of tiny fossils can just completely overturn that accepted scenario of vertebrate evolution,” he said. “I think this is one important step toward figuring out what our distant ancestors actually looked like 500 million years ago.”

Both Janvier and Docker agree that the discovery is important, even if some scientists had already suspected it before. Docker called it “quite exciting.”

“There’s a big difference between thinking it and having the clear evidence,” she said. “So it’s certainly a big deal.”

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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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