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Gravitational waves reveal merger between black hole and mystery 'mass gap' object – CTV News

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A mysterious astronomical object merged with a black hole 780 million light-years away and created gravitational waves that could be detected on Earth. The object exists inside what scientists call the “mass gap,” a range between the heaviest known neutron star and the lightest known black hole. And it could change how astronomers understand black holes.

In August 2019, astronomers using gravitational wave detectors in the US and Italy detected ripples in space and time, a gravitational wave event they dubbed GW190814. Given the fact that this occurred so far from Earth, the event occurred 780 million years ago, but the gravitational waves are just now reaching us.

The merger occurred between an object that was 2.6 times the mass of our sun with a black hole that was 23 times the mass of our sun. This large difference in the sizes of both objects, differing by a factor of nine, makes it the most extreme mass ratio for a gravitational wave event known to date.

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The merger led to a black hole about 25 times the mass of the sun. Some of the mass was blasted out as gravitational waves.

The Laser Interferometer Gravitational-Wave Observatory, or LIGO, and Virgo were used to detect the event. The National Science Foundation’s LIGO includes two detectors — one in Livingston, Louisiana, and another in Hanford, Washington. The Virgo detector is located in Cascina, Italy.

Black holes are created when massive stars die and collapse. Stars that are less massive explode in a supernova. The remnant of this outburst is a neutron star, which is small but very dense.

Currently, the heaviest known neutron star is 2.5 times the mass of our sun and the lightest black hole is five times the mass of our sun. In between is the “mass gap” into which this object fits.

An international team of astronomers were involved in the study, which published Tuesday in The Astrophysical Journal Letters.

“We’ve been waiting decades to solve this mystery,” said Vicky Kalogera, study coauthor and Daniel I. Linzer distinguished university professor of physics and astronomy at Northwestern University, in a statement.

“Mergers of a mixed nature — black holes and neutron stars — have been predicted for decades, but this compact object in the mass gap is a complete surprise. We are really pushing our knowledge of low-mass compact objects,” Kalogera said.

“Even though we can’t classify the object with conviction, we have seen either the heaviest known neutron star or the lightest known black hole. Either way, it breaks a record,” said Kalogera, who is also director of Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA).

A DIFFERENT KIND OF DETECTION

When LIGO and Virgo scientists detected this event, they sent out an immediate alert across the astronomy community to allow for follow-up by Earth and space-based telescopes. The hope is to find light waves also caused by the event.

This has only been seen once during a gravitational wave event, known as GW170817, which occurred in August 2017. It was the result of two neutron stars colliding and releasing light, gravitational waves and even creating elements like gold. Neutron star collisions are fiery, energetic and messy, releasing matter in all directions, and light is a by-product.

Mergers between two black holes, however, aren’t believed to create light.

When telescopes followed up on the August 2019 event, they didn’t pick up any signals of light waves. Scientists believed this is due to the distance of the event, which was six times farther away than the 2017 merger. If it was in fact a merger between two black holes, no light would be produced. And if it was a neutron star, the black hole was so much larger that it may have simply swallowed it.

“I think of Pac-Man eating a little dot,” Kalogera said. “When the masses are highly asymmetric, the smaller compact object can be eaten by the black hole in one bite.”

The detection challenges current theoretical models of how stars die as well as how they pair up in binary systems. Binary systems, like two stars orbiting each other, occur when the two objects are close enough for gravity to create a central orbit.

“The mass gap has been an interesting puzzle for decades, and now we’ve detected an object that fits just inside it,” said Pedro Marronetti, program director for gravitational physics at the National Science Foundation, in a statement.

“That cannot be explained without defying our understanding of extremely dense matter or what we know about the evolution of stars,” Marronetti said. “This observation is yet another example of the transformative potential of the field of gravitational-wave astronomy, which brings novel insights to light with every new detection.”

AN ASYMMETRIC BINARY SYSTEM

The researchers said they didn’t expect to find a binary system including two objects with such different masses, but now they know these are actually being created somewhere in the universe. Next, they have the challenge of trying to figure out what exactly they are and how they work, according to Alberto Vecchio, study co-author and director of the Institute for Gravitational Wave Astronomy.

Though the opportunity to study this event in detail has passed, this discovery will change the way astronomers understand and study neutron stars and black holes going forward.

Future detections of similar events could help astronomers determine if there are more objects that exist in the mass gap.

“This is the first glimpse of what could be a whole new population of compact binary objects,” said study coauthor Charlie Hoy, a member of the LIGO Scientific Collaboration and a graduate student at Cardiff University, in a statement.

“What is really exciting is that this is just the start,” Hoy said. “As the detectors get more and more sensitive, we will observe even more of these signals, and we will be able to pinpoint the populations of neutron stars and black holes in the universe.”

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SpaceX launch marks 300th successful booster landing – Phys.org

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Credit: Unsplash/CC0 Public Domain

SpaceX sent up the 30th launch from the Space Coast for the year on the evening of April 23, a mission that also featured the company’s 300th successful booster recovery.

A Falcon 9 rocket carrying 23 of SpaceX’s Starlink internet satellites blasted off at 6:17 p.m. Eastern time from Cape Canaveral Space Force Station’s Space Launch Complex 40.

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The first-stage booster set a milestone of the 300th time a Falcon 9 or Falcon Heavy booster made a successful recovery landing, and the 270th time SpaceX has reflown a booster.

This particular booster made its ninth trip to space, a resume that includes one human spaceflight, Crew-6. It made its latest recovery landing downrange on the droneship Just Read the Instructions in the Atlantic Ocean.

The company’s first successful booster recovery came in December 2015, and it has not had a failed booster landing since February 2021.

The current record holder for flights flew 11 days ago making its 20th trip off the .

SpaceX has been responsible for all but two of the launches this year from either Kennedy Space Center or Cape Canaveral with United Launch Alliance having launched the other two.

SpaceX could knock out more launches before the end of the month, putting the Space Coast on pace to hit more than 90 by the end of the year, but the rate of launches by SpaceX is also set to pick up for the remainder of the year with some turnaround times at the Cape’s SLC-40 coming in less than three days.

That could amp up frequency so the Space Coast could surpass 100 launches before the end of the year, with the majority coming from SpaceX. It hosted 72 launches in 2023.

More launches from ULA are on tap as well, though, including the May 6 launch atop an Atlas V rocket of the Boeing CST-100 Starliner with a pair of NASA astronauts to the International Space Station.

ULA is also preparing for the second launch ever of its new Vulcan Centaur rocket, which recently received its second Blue Origin BE-4 engine and is just waiting on the payload, Sierra Space’s Dream Chaser spacecraft, to make its way to the Space Coast.

Blue Origin has its own it wants to launch this year as well, with New Glenn making its debut as early as September, according to SLD 45’s range manifest.

2024 Orlando Sentinel. Distributed by Tribune Content Agency, LLC.

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SpaceX launch marks 300th successful booster landing (2024, April 24)
retrieved 24 April 2024
from https://phys.org/news/2024-04-spacex-300th-successful-booster.html

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Wildlife Wednesday: loons are suffering as water clarity diminishes – Canadian Geographic

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The common loon, that icon of northern wilderness, is under threat from climate change due to declining water clarity. Published earlier this month in the journal Ecology, a study conducted by biologists from Chapman University and Rensselaer Polytechnic Institute in the U.S. has demonstrated the first clear evidence of an effect of climate change on this species whose distinct call is so tied to the soundscape of Canada’s lakes and wetlands.

Through the course of their research, the scientists found that July rainfall results in reduced July water clarify in loon territories in Northern Wisconsin. In turn, this makes it difficult for adult loons to find and capture their prey — mainly small fish — underwater, meaning they are unable to meet their chicks’ metabolic needs. Undernourished, the chicks face higher mortality rates. The consistent foraging techniques used by loons across their range means this impact is likely echoed wherever they are found — from Alaska to Canada to Iceland.

The researchers used Landsat imagery to find that there has been a 25-year consistent decline in water clarity, and during this period, body weights of adult loon and chicks alike have also declined. With July being the month of most rapid growth in young loons, the study also pinpointed water clarity in July as being the greatest predictor of loon body weight. 

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One explanation for why heavier rainfall leads to reduced water clarity is the rain might carry dissolved organic matter into lakes from adjacent streams and shoreline areas. Lawn fertilizers, pet waste and septic system leaks may also be to blame.

The researchers, led by Chapman University professor Walter Piper, hope to use these insights to further conservation efforts for this bird Piper describes as both “so beloved and so poorly understood.”

Return of the king

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Giant prehistoric salmon had tusk-like teeth for defence, building nests

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The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.

Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.

It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.

But then came discovery of two skulls in 2014.

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Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.

“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.

In that position, the tusk-like teeth could not have been used for biting, he says.

“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.

“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.

Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”

It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.

The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.

It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.

Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.

“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.

Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature.

“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.

“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”

Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.

“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”

This report by The Canadian Press was first published April 24, 2024.

Brenna Owen, The Canadian Press

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