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When neutron stars collide they produce an explosion that is, contrary to what was believed until recently, shaped like a perfect sphere. Although how this is possible is still a mystery, the discovery may provide a new key to fundamental physics and to measuring the age of the universe. The discovery was made by astrophysicists from the University of Copenhagen and has just been published in the journal Nature.

Kilonovae—the giant explosions that occur when two neutron stars orbit each other and finally collide—are responsible for creating both great and small things in the universe, from black holes to the atoms in the gold ring on your finger and the iodine in our bodies. They give rise to the most extreme physical conditions in the universe, and it is under these extreme conditions that the universe creates the heaviest elements of the periodic table, such as gold, platinum and uranium.

But there is still a great deal we do not know about this violent phenomenon. When a kilonova was detected at 140 million light-years away in 2017, it was the first time scientists could gather detailed data. Scientists around the world are still interpreting the data from this colossal explosion, including Albert Sneppen and Darach Watson from the University of Copenhagen, who made a surprising discovery.

Observations of supermassive black holes at the centers of galaxies point to a likely source of dark energy—the ‘missing’ 70% of the universe.

The measurements from ancient and dormant galaxies show black holes growing more than expected, aligning with a phenomenon predicted in Einstein’s theory of gravity. The result potentially means nothing new has to be added to our picture of the universe to account for dark energy: black holes combined with Einstein’s gravity are the source.

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Over 50 percent of high-mass stars reside in multiple star systems. But due to their complex orbital interactions, physicists have a difficult time understanding just how stable and long-lived these systems are. Recently a team of astronomers applied machine learning techniques to simulations of multiple star systems and found a new way that stars in such systems can arrange themselves.

Classical mechanics has a notorious problem known as the three-body problem. While Newton’s laws of gravity can easily handle calculations of the forces between two objects and their subsequent evolution, there is no known analytic solution when you include a third massive object. In response to that problem, physicists over the centuries have developed various approximation schemes to study these kinds of systems, concluding that the vast majority of possible three-object arrangements are unstable.

But it turns out that there are a lot of multiple-star systems out there in the galaxy. Indeed, over half of all massive stars belong to at least a binary pair, and many of them belong to triple or quadruple star systems. Obviously, the systems last a long time. Otherwise, they would have flung themselves apart a long time ago before we had a chance to observe them. But because of the limitations of our tools, we have difficulty assessing how these systems organize themselves and what stable orbit options exist.

Source of Dark Energy is black holes combined with Einstein’s gravity — experts Result potentially means nothing new has to be added to our picture of Universe It makes up most of the universe, yet hardly anything is known about the so-called Dark Energy that envelopes us. The unusual ‘something’ – one of the great mysteries of cosmology – is believed to be an unknown force that is pushing things apart more strongly than gravity and causing the universe’s expansion to accelerate.

Measurements of the magnetic moment of the electron have achieved unprecedented accuracy, showing great potential for the search for physics beyond the standard model.

Despite its remarkable successes, the standard model of particle physics clearly isn’t complete—dark matter, dark energy, and the matter–antimatter asymmetry of the Universe are some of its most flagrant deficiencies. Experimenters thus eagerly search for anomalies that could provide hints on a theory that could complete or replace the standard model. The electron is a key player in this quest: its magnetic moment is both the most precisely measured elementary-particle property and the most accurately verified standard model prediction to date. New measurements by Gerald Gabrielse’s group at Northwestern University in Illinois [1] have determined the value of the electron’s magnetic moment 2.2 times more accurately than the previous best estimate, which was obtained in 2008 [2].

To put it one way, it’s the observation that our cosmos is in the process of ripping itself apart.

Research in fundamental science has revealed the existence of quark-gluon plasma (QGP)—a newly identified state of matter—as the constituent of the early universe. Known to have existed a microsecond after the Big Bang, the QGP, essentially a soup of quarks and gluons, cooled down with time to form hadrons like protons and neutrons—the building blocks of all matter.

One way to reproduce the extreme conditions prevailing when QGP existed is through relativistic heavy-ion collisions. In this regard, particle accelerator facilities like the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider have furthered our understanding of QGP with experimental data pertaining to such collisions.

Meanwhile, theoretical physicists have employed multistage relativistic hydrodynamic models to explain the data, since the QGP behaves very much like a perfect fluid. However, there has been a serious lingering disagreement between these models and data in the region of low transverse momentum, where both the conventional and hybrid models have failed to explain the particle yields observed in the experiments.

Last summer, the gravitational wave observatory known as LIGO caught its second-ever glimpse of two neutron stars merging. The collision of these incredibly dense objects — the hulking cores of long-ago supernova explosions — sent shudders through space-time powerful enough to be detected here on Earth. But unlike the first merger, which conformed to expectations, this latest event has forced astrophysicists to rethink some basic assumptions about what’s lurking out there in the universe. “We have a dilemma,” said Enrico Ramirez-Ruiz of the University of California, Santa Cruz.

The exceptionally high mass of the two-star system was the first indication that this collision was unprecedented. And while the heft of the stars alone wasn’t enough to cause alarm, it hinted at the surprises to come.

In a paper recently posted to the scientific preprint site arxiv.org, Ramirez-Ruiz and his colleagues argue that GW190425, as the two-star system is known, challenges everything we thought we knew about neutron star pairs. This latest observation appears to be fundamentally incompatible with scientists’ current understanding of how these stars form, and how often. As a result, researchers may need to rethink years of accepted knowledge.

One of Albert Einstein’s theory of general relativity’s most fascinating predictions is the possibility of black holes, which are created after a massive star reaches the end of its life and collapses. Supermassive black holes as big as 100,000 or ten billion times the Sun are commonly found at the center of most galaxies.

Those are the biggest form of black holes, but it is also thought that primordial black holes (PBHs) also exist. Unlike the big ones, these tiny black holes emerged in the early cosmos through the gravitational collapse of extraordinarily dense areas.