Some of the most violent cosmic collisions occur silently in the vacuum of space, but with the right instrumental ears, we can still hear it happen. Here’s how.
A recently discovered formation of galaxies spanning 3.3 billion light-years is one of the largest known structures in the universe, contradicting some of the most fundamental beliefs of astronomers about the cosmos. The Giant Arc is composed of galaxies, galaxy clusters, and a significant amount of gas and dust. It is located 9.2 billion light-years away and covers approximately one-fifteenth of the visible universe.
The discovery was “fortuitous,” according to Alexia Lopez, a doctoral candidate in cosmology at the University of Central Lancashire (UCLan) in the United Kingdom. Lopez was creating maps of the night sky using light from around 120,000 quasars, which are the bright centres of galaxies where supermassive black holes consume matter and generate energy.
By measuring magnesium’s imprints, Lopez could calculate the distance to the intervening gas and dust, as well as the composition of the substance. The quasars were used as “spotlights in a dark room,” illuminating the intervening matter, according to Lopez. A structure began to emerge in the middle of the cosmic maps, a massive arc that was an indication of the Giant Arc.
If I were a brilliant physicist, I would have written this.
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Continue reading “I don’t believe in free will. This is why” »
The quantum fluctuations that pervade empty space spontaneously give birth to pairs of particles and antiparticles. Ordinarily, these pairs annihilate so promptly that their existence is virtual. But a powerful field can pull a pair’s members apart for long enough that their existence becomes real. In 1951 Julian Schwinger calculated how strong an electric field needs to be to beget electron–positron pairs. Now Michael Wondrak and his colleagues of Radboud University in the Netherlands have proposed that particle pairs can be brought into existence by the immense gravitational tidal forces around a black hole [1].
Wondrak and his colleagues considered all the paths a pair of virtual particles could take during their brief existence. If the vacuum is stable, all pairs that are created are also destroyed. But a strong field destabilizes the vacuum, makes some paths more likely than others, and leads to a deficit of pairs that recombine. The deficit is balanced by a net outflow of real particles, which, in the case of a black hole’s gravitational field, leads to the black hole’s eventual evaporation.
The theorists’ approach is sufficiently general that it could reproduce not only Schwinger’s effect but also Stephen Hawking’s 1974 proposal that if a particle–antiparticle pair springs into virtual existence near a black hole’s event horizon, one member could fall in while the other escapes. What’s more, the researchers found that Hawking’s effect is a special case of a more general phenomenon. Pulling virtual particles into existence depends only on the stretching of spacetime wrought by a curved gravitational field and does not require an event horizon as Hawking originally suggested. One intriguing implication is that a neutron star, whose Schwarzschild radius lies beneath the stellar surface, can also beget particle pairs and decay.
They are known as ultra-fast outflows (UFOs), powerful space winds emitted by the supermassive black holes (SMBHs) at the center of active galactic nuclei (AGNs) – aka. “quasars.” These winds (with a fun name!) move close to the speed of light (relativistic speeds) and regulate the behavior of SMBHs during their active phase.
These gas emissions are believed to fuel the process of star formation in galaxies but are not yet well understood. Astronomers are interested in learning more about them to improve our understanding of what governs galactic evolution.
This is the purpose of the SUper massive Black hole Winds in the x-rAYS (SUBWAYS) project, an international research effort dedicated to studying quasars using the ESA’s XMM-Newton space telescope.
NASA recently made an extraordinary discovery of a large thermonuclear explosion in space, caused by a pulsar, which is the remains of a star that did not explode to form a black hole. The National Aeronautics and Space Administration was able to detect the explosion thanks to the strong beam of X-rays sent out by the burst, which was picked up by the agency’s orbiting observatory NICER.
This discovery serves as a potent reminder of the dangers that lurk in space. According to a study published in The Astrophysical Journal Letters in August, the burst released as much energy as the sun does in ten days in just twenty seconds.
The leader of the study and astrophysicist, Peter Bult, said in a statement from NASA, “This burst was great.” Bult also added that the study revealed a two-step change in brightness that they believe was caused by the ejection of separate layers from the pulsar’s surface. These features provide significant information to understand how these events work.
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Hello and welcome! My name is Anton and in this video, we will talk about a strange discovery of excess of dark matter and other related mysteries.
Paper: https://arxiv.org/pdf/2007.15633.pdf.
Paper: https://science.sciencemag.org/content/369/6509/1347
Illustris Project: https://www.illustris-project.org/explorer/
Continue reading “Another Major Dark Matter Mystery Challenges Scientists” »
Physicists have long puzzled over why there is more matter in the Universe than its flipped twin, antimatter. Without this imbalance, the two types of material would have canceled out, leaving nothing but a boring glow in the vast emptiness of space.
Somehow, at some point, something changed in the way the Universe works on a fundamental level, favoring the mirrored state – or parity – of one kind of ‘stuff’ over the other.
Continue reading “Signs of a Critical Imbalance in Physics Seen in The Arrangements of Galaxies” »
A recent discovery made by astronomers operating the Hubble Space Telescope has revealed the presence of a black hole at the center of a dwarf galaxy that actually creates stars instead of consuming them. This revelation has challenged the common perception that black holes only destroy matter.
The method by which stars are formed in this particular dwarf galaxy, named Henize 2–10, is fundamentally different from how stars are formed in larger galaxies. Astronomers have observed that gas moves around the black hole before merging with a core of dense gas present in the galaxy.
The Hubble spectroscopy revealed that the outflow of this gas was traveling at a rate of a million miles per hour, which eventually collided with the dense gas present in the galaxy. The outflow created clusters of newly born stars on its path.
There is a lot of speculation about the end of the universe. Humans love a good ending after all. We know that the universe started with the Big Bang and it has been going for almost 14 billion years. But how the curtain call of the cosmos occurs is not certain yet. There are, of course, hypothetical scenarios: the universe might continue to expand and cool down until it reaches absolute zero, or it might collapse back onto itself in the so-called Big Crunch. Among the alternatives to these two leading theories is “vacuum decay”, and it is spectacular – in an end-of-everything kind of way.
While the heat death hypothesis has the end slowly coming and the Big Crunch sees a reversal of the universe’s expansion at some point in the future, the vacuum decay requires that one spot of the universe suddenly transforms into something else. And that would be very bad news.
There is a field that spreads across the universe called the Higgs field. Interaction between this field and particles is what gives the particles mass. A quantum field is said to be in its vacuum state if it can’t lose any energy but we do not know if that’s true for the Higgs field, so it’s possible that the field is in a false vacuum at some point in the future. Picture the energy like a mountain. The lowest possible energy is a valley but as the field rolled down the slopes it might have encountered a small valley on the side of that mountain and got stuck there.
