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Scientists ‘hear’ cosmic hum from gravitational waves

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Scientists ‘hear’ cosmic hum from gravitational waves

Astronomers say they have found the first evidence of a long-theorised form of gravitational waves that create a “background hum” rumbling throughout the universe.

The findings, unveiled on Wednesday, are the product of years of work by hundreds of scientists using radio telescopes in North America, Europe, China, India and Australia, and have been hailed as an important breakthrough that opens a new window into the universe.

First predicted by Albert Einstein more than a century ago, gravitational waves are ripples in the fabric of the universe that travel through everything at the speed of light almost entirely unimpeded.

Their existence was not confirmed until 2015, when observatories in the United States and Italy detected the first gravitational waves created by two black holes colliding.

These “high-frequency” waves were the result of a single violent event sending a strong, short burst rippling towards Earth.

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But for decades, scientists have also been searching for low-frequency gravitational waves, thought to be constantly rolling through space like background noise.

These slow ripples can take years or even decades to cycle up and down, and probably come from some of the biggest objects in our universe: supermassive black holes billions of times the mass of the Sun.

Joining forces under the banner of the International Pulsar Timing Array consortium, the scientists have finally found strong evidence of these background waves.

“We now know that the universe is awash with gravitational waves,” Michael Keith of the European Pulsar Timing Array told the AFP news agency.

Using dead stars as clocks

As gravitational waves travel through space, they very subtly squeeze and stretch everything they pass through.

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To find evidence of this squeezing and stretching at low frequencies, astronomers looked at pulsars, the dead cores of stars that exploded in a supernova. Some spin hundreds of times a second, flashing beams of radio waves at extremely regular intervals, like cosmic lighthouses.

This means they can act as “a very, very precise clock”, Keith said.

For the new research, radio telescopes around the world were aimed at a total of 115 pulsars throughout the Milky Way.

Scientists then measured the incredibly small differences in the timing of the pulses, searching for telltale signs of gravitational waves. French astrophysicist Antoine Petiteau said they were able to “detect changes of less than one-millionth of a second across more than 20 years”.

The early evidence was consistent with Einstein’s theory of relativity and science’s current understanding of the universe, the scientists said.

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Maura McLaughlin of the US Pulsar Search Collaboratory programme said they were “awestruck” after first seeing evidence of the waves in 2020.

It was “really a magical moment,” she told a press conference.

But the scientists emphasised they had not yet definitively “detected” the waves because they have not reached the gold-standard five sigma level of certainty. Five sigma indicates that there is a one-in-a-million chance of something being a statistical fluke.

“We’re frustratingly just shy of the mark,” said Keith, adding that there was a 99-percent probability that the evidence points to gravitational waves.

Each country or group in the consortium published their research separately in a range of journals.

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Steve Taylor, chair of North America’s NANOGrav gravitational wave observatory, said that once all the data was combined, the five sigma mark could be reached in a year or two.

The leading theory is that the waves are coming from pairs of supermassive black holes sitting at the centre of galaxies that are slowly merging. Unlike those that caused the previously detected gravitational waves, these black holes are almost unimaginably huge – sometimes billions of times bigger than the Sun.

Daniel Reardon, a member of Australia’s Parkes Pulsar Timing Array, said that – if confirmed – the waves would be “the sum of all of the supermassive black hole binary systems whirling around each other at the cores of galaxies everywhere in the universe”.

The researchers described the universe’s gravitational wave background as the equivalent of hearing the hum of a large group of people talking at a party, without being able to distinguish any individual voice.

Another theory is that the gravitational waves could be from the rapid expansion that came within a second after the Big Bang, a period called cosmic inflation that is hidden from the view of scientists.

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Some scientists said the galaxies between Earth and the Big Bang were probably “drowning out” such waves.

But in the future, low-frequency gravitational waves could reveal more about this early expansion and possibly shed light on the mystery of dark matter, the scientists said.

It could also help them understand more about how black holes and galaxies form and evolve.

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Reacher Gets Early Season 4 Renewal Ahead of Amazon Hit’s 2025 Return

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Reacher Gets Early Season 4 Renewal Ahead of Amazon Hit’s 2025 Return


‘Reacher’ Renewed Season 4 at Amazon — Alan Ritchson Star



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The history of the Hoxne Hoard, the largest collection of Roman treasure found in Britain

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The history of the Hoxne Hoard, the largest collection of Roman treasure found in Britain

The Hoxne Hoard is one of Britain’s unique archaeological finds, not just by its value, but also by how it was found.

Various sources note the Hoxne Hoard as the largest hoard of Roman treasure ever found in Britain. The collection of treasures is heavily made up of gold and silver coins, though there are other objects, such as tableware and jewelry that were also found.  

How this collection of ancient treasures was found adds to its uniqueness. 

The Hoxne Hoard is primarily made up of coins. (CM Dixon/Print Collector/Getty Images)

SANXINGDUI RUINS WERE DISCOVERED ACCIDENTALLY BY A FARMER; HAS SINCE BEEN THE SITE OF OVER 60K RELICS

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On Nov. 16, 1992, Eric Lawes was scouring a field in Hoxne village in Suffolk, not on the hunt for hidden treasure, but simply looking for a hammer that had been lost on the land. 

Lawes was scanning the area with his metal detector, when he came across a small portion of the treasures within what would become the Hoxne Hoard. 

After shoveling up some of the silver spoons and gold coins he found, he quickly reported his find to be properly excavated. 

Lawes was awarded £1.75 million for his find, which he shared with the farmer who owned the land the treasures were discovered on, according to the Smithsonian Magazine. 

A close-up photo of a metal detector

While looking for a lost hammer with a metal detector, a man came across a find far bigger. This discovery later became known as the Hoxne Hoard. (iStock)

THE 4,000 ITEMS IN THE STAFFORDSHIRE HOARD MAKE IT THE LARGEST COLLECTION IN HISTORY OF ITS KIND

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The very next day, the Suffolk County Council Archaeology Service (SCCAS) was on the scene, according to the World History Encyclopedia. 

The gold and silver artifacts part of the Hoxne Hoard weigh around 60 pounds in total, according to Ancient Origins. There are around 15,000 Roman coins as part of the collection, per The British Museum, where many of the items are displayed today. The items were buried in the 5th century A.D. 

Other unique finds include pieces of jewelry, like a body chain, six necklaces, three finger rings and gold bracelets, according to the source. 

Gold bracelet from the Hoxne Hoard

There were many pieces of jewelry found as part of the Hoxne Hoard, including gold bracelets. (CM Dixon/Print Collector/Getty Images)

MOM, SON DIG UP ANCIENT OBJECT OFTEN FOUND NEAR BURIAL GROUNDS WHILE GARDENING

Even though the Hoxne Hoard is heavily made up of coins, one of the best-known treasures that was found was the “Empress” pepper pot. This pot was one of four that were excavated from the site, according to The British Museum. The pepper pot is intricately formed to represent a woman. 

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Additionally, there were many tableware items that were part of the hoard, including a set of 19 spoons, in good condition, that were decorated with marine themes, according to The British Museum. 

Archaeologists believe that the Hoxne Hoard was buried no later than 450 A.D., according to Ancient Origins. 

At the end of the 4th century A.D., the western Roman Empire was in a place of uncertainty, with Roman soldiers exiting Britain, leaving citizens to fend for themselves. 

Pepper pot from the Hoxne Hoard

One of the significant finds of the Hoxne Hoard is the pepper pot pictured above. (CM Dixon/Print Collector/Getty Images)

 

While experts have posed varying hypotheses as to why the hoard was buried, one common suggestion is that it was done for protection, with the intent of the owners collecting their precious items once again. In the case of the Hoxne Hoard, the items were never retrieved by their owners. 

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Today, the Hoxne Hoard is on display at the British Museum in London. The display contains many of the coins, jewelry and tableware, as well as Lawes’ hammer, which he was originally looking for when he stumbled upon the far more significant discovery. 

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Greece confronts disastrously low birth rate in Aegean Islands

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Greece confronts disastrously low birth rate in Aegean Islands

At 1.3 babies per woman, Greece’s fertility rate is among Europe’s lowest — and well below the threshold for population growth.

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Authorities in the Aegean Islands have warned that low birth rates spell disaster for their region.

Mayors from the islands expressed serious concerns during the 15th Congress of Small Islands in Milos, where they lamented the continuous downward trend of Greece’s births-to-deaths ratio and said the consequences were already visible in their communities.

A case in point is Agios Efstratios, a small island in the north Aegean with no more than 250 inhabitants.

‘’There are no girls on the island. Or at least there are no more than 2 women under 30 years old,” said Kostas Sinanis, the local mayor.

“The same goes for the boys. We need to search for the incentives that will bring the young boys and girls back to the island, the place where they were born and raised, to create their families. Unfortunately, we had one birth last year and another one three years ago.”

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In 2022, Greece recorded its lowest number of births in 92 years — and this year, the country posted the second-largest population decrease in the EU.

Greece’s fertility rate is among the continent’s lowest at 1.3 babies per woman, well below the 2.5 needed for population growth. Economic forecasts indicate its workforce will fall by 50% by 2100, with its output shrinking by 31% over the same period.

Michalis Vlastarakis of the Eurobank Group warned that if nothing is done, disaster will follow.

‘’If we don’t do something, in about 25 years from now, in two decades, one-third of the population will be over 65 years old, and in 2050 we will be 2.5 million less”, said Vlastakaris.

“You don’t need to have studied finance to understand the consequences of these projections on economic indicators, GDP, the workforce, the insurance system, pensions, health, and education, even since there’re going to be fewer schools.’’

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Greece’s family ministry said a few days ago that it plans to spend €20 billion through 2035 on incentives to halt the decline, including cash benefits and tax breaks.

The government already spends around €1 billion a year on pro-child measures — but like other European countries doing the same, it has seen little impact.

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