The history of the universe is predicated on the idea that, compared to today, the universe was hotter and more symmetric in its early phase. Scientists have thought this because of the Higgs Boson finding—the particle that gives mass to all other fundamental particles. The concept is that as one analyzes time back toward the Big Bang, the universe gets hotter and the Higgs phase changes to one where everything became massless. Now, physicists are presenting a new theory that suggests an alternative history of the universe is possible.
Category: cosmology – Page 370
Why does time seem to move forward? It’s a riddle that’s puzzled physicists for well over a century, and they’ve come up with numerous theories to explain time’s arrow. The latest, though, suggests that while time moves forward in our universe, it may run backwards in another, mirror universe that was created on the “other side” of the Big Bang.
Two leading theories propose to explain the direction of time by way of the relatively uniform conditions of the Big Bang. At the very start, what is now the universe was homogeneously hot, so much so that matter didn’t really exist. It was all just a superheated soup. But as the universe expanded and cooled, stars, galaxies, planets, and other celestial bodies formed, birthing the universe’s irregular structure and raising its entropy.
One theory, proposed in 2004 by Sean Carroll, now a professor at Caltech, and Jennifer Chen, then his graduate student, says that time moves forward because of the contrast in entropy between then and now, with an emphasis on the fact that the future universe will so much more disordered than the past. That movement toward high entropy gives time its direction.
The most powerful laser beam ever created has been recently fired at Osaka University in Japan, where the Laser for Fast Ignition Experiments (LFEX) has been boosted to produce a beam with a peak power of 2,000 trillion watts—two petawatts—for an incredibly short duration, approximately a trillionth of a second or one picosecond.
Values this large are difficult to grasp, but we can think of it as a billion times more powerful than a typical stadium floodlight or as the overall power of all of the sun’s solar energy that falls on London. Imagine focusing all that solar power onto a surface as wide as a human hair for the duration of a trillionth of a second: that’s essentially the LFEX laser.
LFEX is only one of a series of ultra-high power lasers that are being built across the world, ranging from the gigantic 192-beam National Ignition Facility in California, to the CoReLS laser in South Korea, and the Vulcan laser at the Rutherford Appleton Laboratory outside Oxford, UK, to mention but a few.
US$190 million in investors’ money has been locked since Cotten died in December. His widow says she doesn’t know his passwords.
About US$190 million in cryptocurrency has been locked away in a online black hole after the founder of a currency exchange died, apparently taking his encrypted access to their money with him.
Investors in QuadrigaCX, Canada’s largest cryptocurrency exchange, have been unable to access their funds since its founder, Gerald Cotten, died last year.
Stunning new images show how black holes produce tremendously bright jets millions of light-years long that can be seen across vast cosmic distances. The images were produced by a computer simulation and could help resolve an enduring mystery about how the jets form, the researchers behind the images said.
Despite their moniker, black holes aren’t always black. As a black hole consumes an object, gas and dust spins around the maw of the gravitational behemoth, and friction can heat the material on the edges to searing temperatures. This violent process creates lighthouse-like beams of charged particles that travel outward at near light speed, emitting radiation that can shine brighter than an entire galaxy. [11 Fascinating Facts About Our Milky Way Galaxy]
“They are like laser beams piercing the universe and allowing us to see black holes whose emission would otherwise be too dim to be detectable,” Alexander Tchekhovskoy, a computational astrophysicist at Northwestern University in Evanston, Illinois, told Live Science.
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.