The team created the so-called quark-gluon plasma by smashing packets of protons and neutrons into a much heavier gold atom in the PHENIX Detector particle collider at Brookhaven National Laboratory in Upton, New York. It is theorised that this matter filled the entire Universe shortly after the Big Bang when it was still too hot for particles to come together to make atoms.
Scientists have been searching for “dark matter” – an unknown and invisible substance thought to make up the vast majority of matter in the universe – for nearly a century. The reason for this persistence is that dark matter is needed to account for the fact that galaxies don’t seem to obey the fundamental laws of physics. However, dark matter searches have remained unsuccessful.
But there are other approaches to make sense of why galaxies behave so strangely. Our new study, published in the Journal of Cosmology and Astroparticle Physics, shows that, by tweaking the laws of gravity on the enormous scales of galaxies, we may not actually need dark matter after all.
The Swiss astronomer Fritz Zwicky discovered in the 1930s that velocities in galaxy clusters were too high to account for how much matter we could see. A similar phenomenon was described by several groups of astronomers, such as Vera Rubin and Kent Ford, when they studied the motion of stars at the far edges of the Andromeda Galaxy.
Dark energy is apparently even more mysterious than astronomers had thought.
Scientists first proposed the existence of this invisible force two decades ago, to explain the surprising discovery that the universe’s expansion is accelerating. (Surprising and incredibly important; the find netted three researchers the Nobel Prize in physics in 2011.)
The most-used astrophysical model of the universe’s structure and evolution regards dark energy as a constant. Indeed, many astronomers believe it to be the cosmological constant, which Einstein posited in 1917 as part of his theory of general relativity. [The History & Structure of the Universe in Pictures].
For the first time, researchers have documented the long-predicted occurrence of ‘walls bound by strings’ in superfluid helium-3. The existence of such an object, originally foreseen by cosmology theorists, may help explaining how the universe cooled down after the Big Bang. With the newfound ability to recreate these structures in the lab, earth-based scientists finally have a way to study some of the possible scenarios that might have taken place in the early universe more closely.
Hints of ghostly galaxies and ancient cataclysms in data from the Gaia spacecraft offer fresh insights into dark matter.
Much as a ripple in a pond reveals a thrown stone, the existence of the mysterious stuff known as dark matter is inferred via its wider cosmic influence. Astronomers cannot see it directly, but its gravity sculpts the birth, shape and movement of galaxies. This makes a discovery from last year all the more unexpected: a weirdly diffuse galaxy that seemed to harbor no dark matter at all.
The Big Bang didn’t just result in our familiar universe, according to a mind-bending new theory — it also generated a second “anti-universe” that extended backwards in time, like a mirror image of our own.
A new story in Physics World explores the new theory, which was proposed by a trio of Canadian physicists who say that it could explain the existence of dark matter.
The new theory, which is laid out in a recent paper in the journal Physical Review of Letters, aims to preserve a rule of physics called CPT symmetry. In the anti-universe before the Big Bang, it suggests, time ran backwards and the cosmos were made of antimatter instead of matter.
Astronomers have announced that they have gathered new data on the black hole that lies at the center of our galaxy. The new information was gleaned when the scientists added the ALMA telescope into the array of telescopes being used to study the black hole. The discovery has found that the emissions from the supermassive black hole, called Sagittarius A (Sgr A), comes from a smaller region than previously believed.
