Archive for the ‘cosmology’ category

Aug 17, 2018

The Universe’s Oldest Galaxies Could Be Right in the Milky Way’s Backyard

Posted by in category: cosmology

The Universe’s earliest epochs appear to be written into the small dwarf galaxies orbiting our own galactic home, the Milky Way.

A team of researchers studying dark matter noticed a strange trend in the brightness of the satellite galaxies around the Milky Way. There seem to be two classes of these orbiting dwarf galaxies—dim ones and bright ones—with few in the middle range. The researchers propose that this kink, when viewed on a graph, could be explained by a period early on in the Universe’s history called the re-ionization era.

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Aug 17, 2018

Another way for stellar-mass black holes to grow larger

Posted by in categories: cosmology, physics

A trio of researchers with The University of Hong Kong, Academia Sinica Institute of Astronomy and Astrophysics in Taiwan and Northwestern University in the U.S., has come up with an alternative theory to explain how some stellar-mass black holes can grow bigger than others. In their paper published in The Astrophysical Journal Letters, Shu-Xu Yi, K.S. Cheng and Ronald Taam describe their theory and how it might work.

Since the initial detection of gravitational waves three years ago, five more detections have been observed—and five of the total have been traced back to emissions created by two stellar-mass black holes merging. The sixth was attributed to neutron stars merging. As part of their studies of such detections, space researchers have been surprised by the size of the stellar-mass black holes producing the gravity waves—they were bigger than other stellar-mass black holes. Their larger size has thus far been explained by the that they grew larger because they began their lives as stars that contained very small amounts of metal—stars with traces of metals would retain most of their mass because they produce weaker solar winds. In this new effort, the researchers suggest another possible way for stellar-mass black holes to grow larger than normal.

The new theory starts out by noting that some at the hearts of galaxies are surrounded by a disk of gas and dust. In such galaxies, there are often stars lying just outside the disk—stars that could evolve to become stellar-mass black holes. The researchers suggest that it is possible that sometimes, pairs of these stars wind up in the disk as they evolve into black holes. Such stellar-mass black holes would pull in material from the disk, causing them to grow larger. The researchers note that if such a scenario were to play out, it is also possible that the two merging could wind up with a synchronized spin resulting in a stellar-mass black hole that produces more gravity waves than if the spins had not been synchronized, making them easier for researchers to spot.

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Aug 15, 2018

This one particle could solve five mega-mysteries of physics

Posted by in categories: cosmology, particle physics

Forget the Higgs: theorists have uncovered a missing link that explains dark matter, what happened in the big bang and more. Now they’re racing to find it.

By Michael Brooks

911? It’s an emergency. The most important particle in the universe is missing. Florian Goertz knows this isn’t a case for the police, but he is still waiting impatiently for a response. This 911 isn’t a phone number, but a building on the northern edge of the world’s biggest particle accelerator.

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Aug 15, 2018

Weird circles in the sky may be signs of a universe before ours

Posted by in categories: cosmology, existential risks, mathematics

By Chelsea Whyte

Swirling patterns in the sky may be signs of black holes that survived the destruction of a universe before the big bang.

“What we claim we’re seeing is the final remnant after a black hole has evaporated away in the previous aeon,” says Roger Penrose, a mathematical physicist at the University of Oxford.

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Aug 14, 2018

Researcher accurately determines energy difference between two quantum states

Posted by in categories: cosmology, particle physics, quantum physics

A kiwi physicist has discovered the energy difference between two quantum states in the helium atom with unprecedented accuracy, a ground-breaking discovery that contributes to our understanding of the universe and space-time and rivals the work of the world’s most expensive physics project, the Large Hadron Collider.

Our understanding of the universe and the forces that govern it relies on the Standard Model of particle physics. This model helps us understand space-time and the fundamental forces that hold everything in the universe in place. It is the most accurate scientific theory known to humankind.

But the Standard Model does not fully explain everything, for example it doesn’t explain gravity, dark matter, dark energy, or the fact that there is way more matter than antimatter in the universe.

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Aug 11, 2018

Star-Swallowing Black Holes Reveal Secrets in Exotic Light Shows

Posted by in category: cosmology

Black holes occasionally reveal themselves when passing stars get ripped apart by their gravity. These tidal disruption events have created a new way for astronomers to map the hidden cosmos.

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Aug 9, 2018

Dark Energy May Be Incompatible With String Theory

Posted by in categories: cosmology, quantum physics

A controversial new paper argues that universes with dark energy profiles like ours do not exist in the “landscape” of universes allowed by string theory.

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Aug 6, 2018

Scientists hope AI will illuminate the mystery of dark matter

Posted by in categories: cosmology, robotics/AI

Scientists are using artificial intelligence to reveal the hidden mysteries of the universe, such as whether or not dark matter actually exists.

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Aug 3, 2018

New Physics Needed to Resolve Universe Expansion Debate?

Posted by in categories: computing, cosmology, physics

Next time you eat a blueberry (or chocolate chip) muffin consider what happened to the blueberries in the batter as it was baked. The blueberries started off all squished together, but as the muffin expanded they started to move away from each other. If you could sit on one blueberry you would see all the others moving away from you, but the same would be true for any blueberry you chose. In this sense galaxies are a lot like blueberries.

Since the Big Bang, the universe has been expanding. The strange fact is that there is no single place from which the universe is expanding, but rather all galaxies are (on average) moving away from all the others. From our perspective in the Milky Way galaxy, it seems as though most galaxies are moving away from us – as if we are the centre of our muffin-like universe. But it would look exactly the same from any other galaxy – everything is moving away from everything else.

To make matters even more confusing, new observations suggest that the rate of this expansion in the universe may be different depending on how far away you look back in time. This new data, published in the Astrophysical Journal, indicates that it may time to revise our understanding of the cosmos.

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Aug 3, 2018

How a multiverse is theoretically possible

Posted by in categories: cosmology, physics

Click on photo to start video.

The multiverse theory could answer questions that remain in physics and astronomy.

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