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Archive for the ‘cosmology’ category: Page 334

Jun 28, 2018

Dark Matter ‘Test’ Will Either Prove Its Existence or Modify Gravity

Posted by in categories: computing, cosmology

For something that supposedly takes up 80 percent of the total mass of the universe, we don’t know a whole lot about dark matter. Sometimes the lightless stuff reveals hints about its shape; other times it completely thwarts any evidence supporting its existence. Since we can’t observe it first-hand, we rely on indirect means to suss out information about it, like watching the interactions between other forms of matter. Now, scientists have developed a new “test” to make those investigations more definitive, leading us closer to answering the question: Is dark matter even real? And if it’s not, then is everything we know about gravity wrong?

In a study, published Monday in Physical Review Letters, a team of scientists from the University of Bonn that also includes Hubble Fellow Marcel S. Pawlowski, Ph.D. of the University of California, Irvine, introduce a computer model that can simulate how certain small galaxies should move if dark matter exists. Though dark matter does not absorb or emit light, it still interacts with visible matter through gravity, so it’s expected to make the stars around galaxies move in specific ways.

Pawlowski explains to Inverse in an email that within the little galaxies in question — satellite “dwarf” galaxies, crowding around the edges of big galaxies like the Milky Way — the acceleration of stars speeding around the galaxy’s center is described by a term called the radial acceleration relation, or RAR. “With the new study, we simulate such dwarf galaxies under the assumption of the ‘standard’ dark matter model, [to] determine what kind of behavior would be expected for the dwarfs,” he says. “We find that the simulated dwarf galaxies largely continue the RAR to lower accelerations.” Now that they know how those dwarf galaxies are supposed to move if dark matter exists, they can compare the simulations to real-life data on the movement of those galaxies.

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Jun 25, 2018

Why the James Webb telescope launch could be the most exciting astrological event of the millennia

Posted by in categories: cosmology, space travel

The NASA James Webb telescope could prove to be the biggest leap forward to humankind’s exploration into deep space.

The Webb telescope will give us the ability to investigate the cosmos, unlocking secrets from the beginning of the Big Bang to how galaxies are formed and beyond, bringing us light years ahead of our current understanding of planetary evolution.

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Jun 21, 2018

Scientists Detect Possible Missing ‘Piece’ Of Universe Created By The Big Bang

Posted by in categories: cosmology, materials

Aside from dark matter and the dark energy that comprised the universe, there remained to be 5 percent of what was called the “ordinary matter.” About two-thirds of this ordinary matter was left unaccounted for until now. ( Harvard-Smithsonian Center for Astrophysics )

After a 20-year-long experiment, a team of international scientists detects the last of the missing intergalactic material predicted to be created by the Big Bang.

Specifically, the team was finally able to detect the missing parts of the “ordinary matter” that makes up everything in the universe, from the stars to the cores of black holes. This ordinary matter is different from the “dark matter” that comprised the bulk of the universe’s mass. The dark matter remained to be undetected until now.

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Jun 20, 2018

Did Scientists Just Find a Missing Piece of the Universe?

Posted by in categories: cosmology, physics

It would be silly to think we completely understand our universe, given how small the Earth is compared to the vastness of the cosmos. But from here on our tiny planet, it appears that much of the universe is missing. And I’m not just talking about dark matter. Regular stuff seems to be missing, too.

Astronomy fans probably know that as far as humans can tell, the universe is composed mostly of some mysterious, unexplained energy called dark energy that pushes it apart. The remaining piece, about a quarter, is dark matter, another unexplained thing that seems to build the universe’s skeleton. Just 4 percent is the regular matter that we can see: stars, planets, and interstellar and intergalactic gas. But the observed amount of this regular matter still falls perhaps a third short of the amount of stuff that physicists think should exist based on their models of the universe.

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Jun 19, 2018

Can Thousands of Smartphones Help Detect Cosmic Rays?

Posted by in categories: cosmology, mobile phones, particle physics

Your smartphone has a particle detector on it, and scientists want you to help them uncover how the universe really works and maybe even discover the true nature of dark matter. There are just a few bugs to work out.

High-energy particles from space, called cosmic rays, constantly bombard the Earth. There are all sorts of things we might be able to learn about the universe by studying those particles. We’ve previously discussed high-tech, expensive equipment used to monitor them. But the physicists behind a new project want your smartphone to help gather data on these cosmic rays, hopefully revealing new insights into dark matter and other strange phenomena.

“This project can only be successful with a large number of people,” Piotr Homola, associate professor at the Institute of Nuclear Physics at the Polish Academy of Sciences, told Gizmodo. “We need public engagement on an unprecedented scale.”

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Jun 19, 2018

Black Holes Could Actually Be Colliding Wormholes

Posted by in categories: cosmology, physics

Like the gravitational waves left behind by merging black holes, detectable ripples in space-time could come from colliding wormholes.

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Jun 19, 2018

Astronomers See Distant Eruption as Black Hole Destroys Star

Posted by in categories: cosmology, materials

For the first time, astronomers have directly imaged the formation and expansion of a fast-moving jet of material ejected when the powerful gravity of a supermassive black hole ripped apart a star that wandered too close to the massive monster.

The scientists tracked the event with radio and infrared telescopes, including the National Science Foundation’s Very Long Baseline Array (VLBA) and NASA’s Spitzer Space Telescope, in a pair of colliding galaxies called Arp 299. The galaxies are nearly 150 million light-years from Earth. At the core of one of the galaxies, a black hole 20 million times more massive than the Sun shredded a star more than twice the Sun’s mass, setting off a chain of events that revealed important details of the violent encounter. The researchers also used observations of Arp 299 made by NASA’s Hubble space telescope prior to and after the appearance of the eruption.

Only a small number of such stellar deaths, called tidal disruption events, or TDEs, have been detected. Theorists have suggested that material pulled from the doomed star forms a rotating disk around the black hole, emitting intense X-rays and visible light, and also launches jets of material outward from the poles of the disk at nearly the speed of light.

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Jun 19, 2018

Best evidence of rare black hole captured

Posted by in category: cosmology

Scientists have been able to prove the existence of small black holes and those that are super-massive but the existence of an elusive type of black hole, known as intermediate-mass black holes (IMBHs) is hotly debated. New research coming out of the Space Science Center at the University of New Hampshire shows the strongest evidence to date that this middle-of-the-road black hole exists, by serendipitously capturing one in action devouring an encountering star.

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Jun 18, 2018

Researchers capture best ever evidence of rare black hole

Posted by in category: cosmology

ESA’s XMM-Newton observatory has discovered the best-ever candidate for a very rare and elusive type of cosmic phenomenon: a medium-weight black hole in the process of tearing apart and feasting on a nearby star.

There are various types of black hole lurking throughout the Universe: massive stars create stellar-mass black holes when they die, while galaxies host supermassive black holes at their centres, with masses equivalent to millions or billions of Suns.

Lying between these extremes is a more retiring member of the black hole family: intermediate-mass black holes. Thought to be seeds that will eventually grow to become supermassive, these black holes are especially elusive, and thus very few robust candidates have ever been found.

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Jun 18, 2018

Meet The Universe’s First-Ever Supermassive Binary Black Holes

Posted by in category: cosmology

If you thought LIGO’s recent discoveries were profound and unusual, wait until you meet OJ 287.

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