Einstein’s theory of general relativity tagged posts

Researchers from the University of Southampton, together with colleagues from the universities of Cambridge and Barcelona, have shown it’s theoretically possible for black holes to exist in perfectly balanced pairs — held in equilibrium by a cosmological force — mimicking a single black hole.

Black holes are massive astronomical objects that have such a strong gravitational pull that nothing, not even light, can escape. They are incredibly dense. A black hole could pack the mass of the Earth into a space the size of a pea.

Conventional theories about black holes, based on Einstein’s theory of General Relativity, typically explain how static or spinning black holes can exist on their own, isolated in space...

Outer reaches of solar system could harbor another planet–or evidence modifying laws of gravity. A pair of theoretical physicists are reporting that the same observations inspiring the hunt for a ninth planet might instead be evidence within the solar system of a modified law of gravity originally developed to understand the rotation of galaxies.

Researchers Harsh Mathur, a professor of physics at Case Western Reserve University, and Katherine Brown, an associate professor of physics at Hamilton College, made the assertion after studying the effect the Milky Way galaxy would have on objects in the outer solar syst...

As the universe evolves, scientists expect large cosmic structures to grow at a certain rate: dense regions such as galaxy clusters would grow denser, while the void of space would grow emptier.

But University of Michigan researchers have discovered that the rate at which these large structures grow is slower than predicted by Einstein’s Theory of General Relativity.

They also showed that as dark energy accelerates the universe’s global expansion, the suppression of the cosmic structure growth that the researchers see in their data is even more prominent than what the theory pr...

Qingdi Wang et al, How the huge energy of quantum vacuum gravitates to drive the slow accelerating expansion of the Universe, Physical Review D (2017). DOI: 10.1103/PhysRevD.95.103504

UBC physicists may have solved one of nature’s great puzzles: what causes the accelerating expansion of our universe? PhD student Qingdi Wang has tackled this question in a new study that tries to resolve a major incompatibility issue between two of the most successful theories that explain how our universe works: quantum mechanics and Einstein’s theory of general relativity. The study suggests that if we zoomed in-way in-on the universe, we would realize it’s made up of constantly fluctuating space and time.

“Space-time is not as static as it appears, it’s constantly moving,” said Wang...