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All Dark Matter in the Universe Could Be Primordial Black Holes – Formed From the Collapse of Baby Universes Soon After the Big Bang – SciTechDaily

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Baby universes branching off of our universe shortly after the Big Bang appear to us as black holes. Credit: Kavli IPMU

The Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) is home to many interdisciplinary projects which benefit from the synergy of a wide range of expertise available at the institute. One such project is the study of black holes that could have formed in the early universe, before stars and galaxies were born.  

Such primordial black holes (PBHs) could account for all or part of dark matter, be responsible for some of the observed gravitational waves signals, and seed supermassive black holes found in the center of our Galaxy and other galaxies. They could also play a role in the synthesis of heavy elements when they collide with neutron stars and destroy them, releasing neutron-rich material.

In particular, there is an exciting possibility that the mysterious dark matter, which accounts for most of the matter in the universe, is composed of primordial black holes. The 2020 Nobel Prize in physics was awarded to a theorist, Roger Penrose, and two astronomers, Reinhard Genzel and Andrea Ghez, for their discoveries that confirmed the existence of black holes. Since black holes are known to exist in nature, they make a very appealing candidate for dark matter. 

The recent progress in fundamental theory, astrophysics, and astronomical observations in search of PBHs has been made by an international team of particle physicists, cosmologists and astronomers, including Kavli IPMU members Alexander Kusenko, Misao Sasaki, Sunao Sugiyama, Masahiro Takada and Volodymyr Takhistov.

To learn more about primordial black holes, the research team looked at the early universe for clues. The early universe was so dense that any positive density fluctuation of more than 50 percent would create a black hole. However, cosmological perturbations that seeded galaxies are known to be much smaller. Nevertheless, a number of processes in the early universe could have created the right conditions for the black holes to form.

Hyper Suprime Cam

Hyper Suprime-Cam (HSC) is a gigantic digital camera on the Subaru Telescope. Credit: HSC project / NAOJ

One exciting possibility is that primordial black holes could form from the “baby universes” created during inflation, a period of rapid expansion that is believed to be responsible for seeding the structures we observe today, such as galaxies and clusters of galaxies. During inflation, baby universes can branch off of our universe. A small baby (or “daughter”) universe would eventually collapse, but the large amount of energy released in the small volume causes a black hole to form.  

An even more peculiar fate awaits a bigger baby universe. If it is bigger than some critical size, Einstein’s theory of gravity allows the baby universe to exist in a state that appears different to an observer on the inside and the outside. An internal observer sees it as an expanding universe, while an outside observer (such as us) sees it as a black hole. In either case, the big and the small baby universes are seen by us as primordial black holes, which conceal the underlying structure of multiple universes behind their “event horizons.” The event horizon is a boundary below which everything, even light, is trapped and cannot escape the black hole.

Andromeda Galaxy Primordial Black Hole

A star in the Andromeda galaxy temporarily becomes brighter if a primordial black hole passes in front of the star, focusing its light in accordance with the theory of gravity. Credit: Kavli IPMU/HSC Collaboration

In their paper, the team described a novel scenario for PBH formation and showed that the black holes from the “multiverse” scenario can be found using the Hyper Suprime-Cam (HSC) of the 8.2m Subaru Telescope, a gigantic digital camera — the management of which Kavli IPMU has played a crucial role — near the 4,200 meter summit of Mt. Mauna Kea in Hawaii. Their work is an exciting extension of the HSC search of PBH that Masahiro Takada, a Principal Investigator at the Kavli IPMU, and his team are pursuing. The HSC team has recently reported leading constraints on the existence of PBHs in Niikura, Takada et. al. Nature Astronomy 3, 524–534 (2019)

Why was the HSC indispensable in this research? The HSC has a unique capability to image the entire Andromeda galaxy every few minutes. If a black hole passes through the line of sight to one of the stars, the black hole’s gravity bends the light rays and makes the star appear brighter than before for a short period of time. The duration of the star’s brightening tells the astronomers the mass of the black hole. With HSC observations, one can simultaneously observe one hundred million stars, casting a wide net for primordial black holes that may be crossing one of the lines of sight.  

The first HSC observations have already reported a very intriguing candidate event consistent with a PBH from the “multiverse,” with a black hole mass comparable to the mass of the Moon. Encouraged by this first sign, and guided by the new theoretical understanding, the team is conducting a new round of observations to extend the search and to provide a definitive test of whether PBHs from the multiverse scenario can account for all dark matter.  

Reference: “Exploring Primordial Black Holes from the Multiverse with Optical Telescopes” by Alexander Kusenko, Misao Sasaki, Sunao Sugiyama, Masahiro Takada, Volodymyr Takhistov and Edoardo Vitagliano, 30 October 2020, Physical Review Letters.
DOI: 10.1103/PhysRevLett.125.181304

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Oldest quasar and supermassive black hole discovered in the distant universe – CTV News

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The most distant quasar and the earliest known supermassive black hole have been discovered, shedding light on how massive galaxies formed in the early universe.

This discovery was revealed Tuesday at the 237th meeting of The American Astronomical Society, happening virtually due to the pandemic. The study has been accepted for publication in the Astrophysical Journal Letters.

A quasar, or quasi-stellar object, is the compact region at the center of a galaxy that throws off enormous energy. They emit so much energy that quasars appear like stars through a telescope. Astronomers believe that the supermassive black holes at the centers of galaxies actually power quasars, acting like an engine.

When gas falls into quasars at the centers of galaxies, they form disks of gas and dust that emit electromagnetic energy. This creates a brightness greater than entire galaxies.

Jets shoot out of the quasar, pulsing with X-rays, and they are some of the hottest things in the entire universe. The jets blow gas and dust, which are essential to form stars, out of the galaxy. When a quasar forms, it signals the end of a galaxy’s star-forming days.

This quasar is a thousand times more luminous than our Milky Way galaxy, and it’s powered by the earliest known supermassive black hole. The light from this quasar took more than 13 billion years to reach Earth, and astronomers were able to observe it as the quasar appeared just 670 million years after the Big Bang.

Its black hole engine weighs more than 1.6 billion times the mass of our sun, making it twice as massive as that of the previous record holder.

“This is the earliest evidence of how a supermassive black hole is affecting the galaxy around it,” said Feige Wang, lead study author and NASA Hubble fellow at the University of Arizona, in a statement. “From observations of less distant galaxies, we know that this has to happen, but we have never seen it happening so early in the Universe.”

The quasar has been dubbed J0313-1806 by the astronomers who discovered it.

“The most distant quasars are crucial for understanding how the earliest black holes formed and for understanding cosmic reionization — the last major phase transition of our Universe,” said Xiaohui Fan, study coauthor and regents professor of astronomy at the University of Arizona, in a statement.

To picture the brightness of this highly energetic object, imagine our sun — but 10 trillion times more luminous.

Astronomers were surprised to discover this quasar was fully formed in such a short time, astronomically speaking, after the Big Bang. The presence of the massive black hole that powers it at this early point in the universe’s timeline also challenges how astronomers understand black hole formation.

For example, how did this black hole have time to form?

“Black holes created by the very first massive stars could not have grown this large in only a few hundred million years,” Wang said.

Typically, such massive black holes form when giant stars explode and collapse, forming black holes that grow in size. They can also form when a dense cluster of stars collapses. Both of these take time.

“This tells you that no matter what you do, the seed of this black hole must have formed by a different mechanism,” Fan said. “In this case, it’s a mechanism that involves vast quantities of primordial, cold hydrogen gas directly collapsing into a seed black hole.”

The brightness of the quasar indicates that the black hole is gobbling up about 25 stars like our sun each year, which powers an outflow of gas moving at 20% the speed of light.

This loss of gas typically halts the birth of stars in a galaxy because that gas is a necessary ingredient in star formation.

“We think those supermassive black holes were the reason why many of the big galaxies stopped forming stars at some point,” Fan said.

Ultimately, the black hole will eventually run out of food, stunting its growth, Fan said.

Multiple telescopes were used in the discovery and astronomers are eager to observe it more in the future.

The galaxy that hosts the quasar is rapidly producing stars at a rate that is 200 times faster than the Milky Way.

“This would be a great target to investigate the formation of the earliest supermassive black holes,” Wang said. “We also hope to learn more about the effect of quasar outflows on their host galaxy — as well as to learn how the most massive galaxies formed in the early Universe.”

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Meet NASA Astronaut & Artemis Team Member Victor Glover [Video] – SciTechDaily

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Victor J. Glover, NASA astronaut candidate class of 2013. Credit: NASA

NASA astronaut Victor Glover is a member of the Artemis Team, a select group of astronauts charged with focusing on the development and training efforts for early Artemis missions.

Victor J. Glover, Jr. was selected as an astronaut in 2013 while serving as a Legislative Fellow in the United States Senate. He is currently serving as pilot and second-in-command on the Crew-1 SpaceX Crew Dragon, named Resilience, which launched November 15, 2020. It is the first post-certification mission of SpaceX’s Crew Dragon spacecraft – the second crewed flight for that vehicle – and a long duration mission aboard the International Space Station. He will also serve as Flight Engineer on the International Space Station for Expedition 64.

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The California native holds a Bachelor of Science in General Engineering, a Master of Science in Flight Test Engineering, a Master of Science in Systems Engineering and a Master of Military Operational Art and Science. Glover is a Naval Aviator and was a test pilot in the F/A‐18 Hornet, Super Hornet and EA‐18G Growler. He and his family have been stationed in many locations in the United States and Japan and he has deployed in combat and peacetime.

Through the Artemis program NASA and a coalition of international partners will return to the Moon to learn how to live on other worlds for the benefit of all. With Artemis missions NASA will send the first woman and the next man to the Moon in 2024 and about once per year thereafter.

Through the efforts of humans and robots, we will explore more of the Moon than ever before; to lead a journey of discovery that benefits our planet with life changing science, to use the Moon and its resources as a technology testbed to go even farther and to learn how to establish and sustain a human presence far beyond Earth.

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Ocean seagrass 'Neptune balls' trap plastic waste, World News & Top Stories – The Straits Times

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PARIS (AFP) – Underwater seagrass in coastal areas appear to trap bits of plastic in natural bundles of fibre known as “Neptune balls”, researchers said on Thursday (Jan 14).

With no help from humans, the swaying plants – anchored to shallow seabeds – may collect nearly 900 million plastic items in the Mediterranean alone every year, they reported in the journal Scientific Reports.

“We show that plastic debris in the seafloor can be trapped in seagrass remains, eventually leaving the marine environment through beaching,” lead author Anna Sanchez-Vidal, a marine biologist at the University of Barcelona, told Agence France-Presse.

This accidental clean-up “represents a continuous purge of plastic debris out of the sea”, she added.

Add pollution control, then, to the long list of services that seagrass provides – for ocean ecosystems, and the humans that live near the water’s edge.

There are some 70 species of marine seagrass, grouped in several families of flowering plants that – originally on land – recolonised the ocean some 80 million to 100 million years ago.

Growing from the Arctic to the tropics, most species have long, grass-like leaves that can form vast underwater meadows.

They are more than just pretty, however.

They play a vital role in improving water quality, absorb CO2 and exude oxygen, and are a natural nursery and refuge for hundreds of species of fish.

They are also the foundation of coastal food webs.

By anchoring shallow waters, they help prevent beach erosion, and dampen the impact of destructive storm surges.

To better understand the plastic bundling capabilities of seagrass, Sanchez-Vidal and her team studied a species found only in the Mediterranean Sea, Posidonia oceanica.

In 2018 and 2019, they counted the number of plastic particles found in seaballs that had washed up on four beaches in Mallorca, Spain, which has large seagrass meadows offshore.

There was plastic debris in half of the loose seagrass leaf samples, up to 600 bits per kilo of leaves.

Only 17 per cent of the tighter bundled seagrass fibre known as Neptune balls contained plastic, but at a much higher density – nearly 1,500 pieces per kilo of seaball.


Growing from the Arctic to the tropics, most species have long, grass-like leaves that can form vast underwater meadows. PHOTO: AFP/UNIVERSITY OF BARCELONA

Using estimates of seagrass fibre production in the Mediterranean, the researchers worked up an estimate of how much plastic might be filtered in the entire basin.

The oval orbs – the shape of a rugby ball – forms from the base of leaves that have been shredded by the action of ocean currents but remain attached to stems, called rhizomes.

As they are slowly buried by sedimentation, the damaged leaf sheaths form stiff fibres that intertwine into a ball, collecting plastic in the process.

“We don’t know where they travel,” said Sanchez-Vidal. “We only know that some of them are beached during storms.”

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