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Category: cosmology – Page 458

Black holes are known to have many strange properties, such as that they allow nothing—not even light—to escape after falling in. A lesser known but equally bizarre property is that black holes appear to “know” what happens in the future in order to form in the first place. However, this strange property arises from the way in which black holes are defined, which has motivated some physicists to explore alternative definitions.

They reported a new area law in general relativity that is based on an interpretation of black holes as curved geometric objects called “holographic screens.”

“The so-called teleology of the black hole event horizon is an artifact of the way in which physicists define an event horizon: the event horizon is defined with respect to infinite future elapsed time, so by definition it ‘knows’ about the entire fate of the universe,” Engelhardt told Phys.org. “In general relativity, the black hole event horizon cannot be observed by any physical observer in finite time, and there isn’t a sense in which the black hole as an entity knows about future infinity. It is simply a convenient way of describing black holes.”

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Great news. It’ll be fascinating to see what they discover.

In the distant reaches of the Universe, exploding stars and supermassive black holes are bending the very fabric of spacetime. It’s hard to wrap our brains around such tremendous forces, but we may be able to quantify them, in the form of gravitational waves. A new European Space Agency mission marks humanity’s first bold attempt to do so in outer space.

This fall, the ESA’s LISA Pathfinder will be blasted into space on a course for the L1 Lagrange point. Situated nearly a million miles from Earth, it’ll begin pilot-testing fundamental technologies for the detection of elusive gravitational waves. The miniature science observatory bid farewell to the public this week, on display at a test centre in Ottobrunn, Germany for the last time before its long journey.

A New Mission Will Search for Ripples in Spacetime

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Brace yourselves: winter is coming. And by winter I mean the slow heat-death of the Universe, and by brace yourselves I mean don’t get terribly concerned because the process will take a very, very, very long time. (But still, it’s coming.)

Based on findings from the Galaxy and Mass Assembly (GAMA) project, which used seven of the world’s most powerful telescopes to observe the sky in a wide array of electromagnetic wavelengths, the energy output of the nearby Universe (currently estimated to be ~13.82 billion years old) is currently half of what it was “only” 2 billion years ago — and it’s still decreasing.

“The Universe has basically plonked itself down on the sofa, pulled up a blanket and is about to nod off for an eternal doze,” said Professor Simon Driver from the International Centre for Radio Astronomy Research (ICRAR) in Western Australia, head of the nearly 100-member international research team.

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  • The universe radiates only half as much energy as 2 billion years ago
  • New findings establish cosmos’ decline with unprecedented precision


From CNN—The universe came in with the biggest bang ever. But now, with a drooping fizzle, it is in its swan song. The conclusion of a new astronomical study pulls no punches on this: “The Universe is slowly dying,” it reads.

Astronomers have believed as much for years, but the new findings establish the cosmos’ decline with unprecedented precision. An international team of 100 scientists used data from the world’s most powerful telescopes — based on land and in space — to study energy coming from more than 200,000 galaxies in a large sliver of the observable universe. [Full story below or at CNN.com]…

Based on those observations, they have confirmed the cosmos is radiating only half as much energy as it was 2 billion years ago. The astronomers published their study on Monday on the website of the European Southern Observatory.

Analysis across many wavelengths shows the universe's electromagnetic energy output is dropping.The team checked the energy across a broad spectrum of lightwaves and other electromagnetic radiation and says it is fading through all wavelengths, from ultraviolet to far infrared.

Analysis across many wavelengths shows the universe’s electromagnetic energy output is dropping.

‘A cold, dark and desolate place’

At the ripe old age of nearly 13.8 billion years, the universe has arrived in its sunset years.

“The universe has basically sat down on the sofa, pulled up a blanket and is about to nod off for an eternal doze,” said astronomer Simon Driver, who led the team.

Death does not mean the universe will go away. It will still be there, but its stars and all else that produces light and stellar fire will fizzle out.

“It will just grow old forever, slowly converting less and less mass into energy as billions of years pass by until eventually, it will become a cold, dark and desolate place, where all of the lights go out,” said astronomer Luke Davies.

But don’t cry for the universe anytime soon. Astrophysicists say this will take trillions of years.

This map shows the light from 380,000 years after the Big Bang in our universe, called the cosmic microwave background, detected by the Planck mission with the greatest precision yet.
First light – 380,000 years after the Big Bang, this light is the cosmic microwave
background. It was detected by the Planck mission with the greatest precision yet.
[See all 6 photos in the series above in the original article]

Bursting with energy

Go all the way back to its birth, and you find a vast contrast. In an infinitesimal fraction of a second, our entire cosmos blasted into existence in the Big Bang.

And the totality of the energy and mass in the universe originates from that moment, astronomers say.

Since that natal explosion, the cosmos has generated other sources of brilliant radiation — most notably stars — by converting some of the mass into energy when extreme gravity causes matter to burst into nuclear fusion.

But the universe is speckled by radiance from seething gas clouds, supernovas and, most spectacularly, the discs of hot matter that rotate around black holes to form quasars, which can be as bright as whole galaxies.

“While most of the energy sloshing around in the universe arose in the aftermath of the Big Bang, additional energy is constantly being generated by stars as they fuse elements like hydrogen and helium together,” Driver said.

Some of the most breathtaking images in the night sky come from quasars. This artist's rendering displays the quasar's luminance, which is brighter than a billion suns. The beam is matter being shot into space.

Fizzling into space

The size and number of those sources of radiation so boggle the mind that it might be hard to imagine that the entirety of that vividness appears to be fading, as its energy flies off through space.

“This new energy is either absorbed by dust as it travels through the host galaxy, or escapes into intergalactic space and travels until it hits something, such as another star, a planet, or, very occasionally, a telescope mirror,” Driver said.

His team observed it from seven of the world’s mammoth telescopes spread out between Australia, the United States, Chile and Earth’s orbit. Many of the instruments specialize in receiving certain wavelengths of light and other electromagnetic waves.

Compiling the data from the collective wavelengths gives the scientists a more complete picture from across a broad spectrum of energy.

Their findings on the universe’s energy slump were part of the larger Galaxy And Mass Assembly, or GAMA, project to study how galaxies are formed. It has mapped out the position of 4 million galaxies so far.