Frequently used to change scenery in science fiction, parallel universes and the multiverse are indeed possible, but jumping from one to another might be a little tricky.
Category: cosmology – Page 335
A proposal for building wormhole-connected black holes offers a way to probe the paradoxes of quantum information.
How can you see something that’s invisible? Well, with Euclid! This future ESA telescope will map the structure of the universe and teach us more about invisible dark matter and dark energy. Scientific coordinator of Euclid and Leiden astronomer Henk Hoekstra explains how this works.
Why do we assume that dark matter exists, if we have never seen it or even measured it? “We are orbiting the centre of our galaxy at 220 kilometres per second,” says Hoeksta. A bizarre speed, which fortunately we don’t notice. Still, something strange is going on. “Based on the number of stars in our Milky Way, the stars at the edge of the Milky Way should have a much lower speed, but they move as fast as the Sun. Yet these stars are not being slung into the universe. Something is holding them together.”
Basically, there can only be one explanation: there is matter that you cannot see, but that exerts extra gravity. In other words, dark matter. Hoekstra: “Or the theory of gravity is wrong. But everything indicates that dark matter exists, only we still don’t know what it is. What we do know is that it does not absorb light or interact with it. So that literally makes it invisible.” If this is not strange enough: since 1998 we know that the expansion of the universe is accelerating. To explain this an even more mysterious ingredient is needed: ‘dark energy,” a term that simply encompasses all ideas that astronomers and physicists are currently studying.
A number that sets the strength of electromagnetic interactions isn’t altered by the extreme gravity around the Milky Way’s supermassive black hole.
Single-purpose quantum computers are helping physicists build simulations of nature’s greatest hits and observe them up close.
Is our Universe really the only one? A new theory that hopes to solve one of the biggest problems in physics, may have rewritten our perception of time, and found a way through the Big Bang. Video by Howard Timberlake.
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Physicists have long searched for hypothesized dark matter particles called WIMPs. Now, focus may be shifting to the axion — an ultra-lightweight particle whose existence would solve two mysteries at once.
How much do you really know about dark matter? Symmetry looks at one of the biggest remaining mysteries in particle physics.
Cosmology draws on many branches of physics to study the universe’s history. And what it’s found has forever changed how we understand our position in the cosmos.
Betelgeuse has been acting strangely, but don’t expect any fireworks in the next 100,000 years; rumors of a pending supernova have all been overhyped.