No light of any kind, including X-rays, can escape from inside the event horizon of a black hole, the region beyond which there is no return.
So we can rule out the possibility that a black hole swallowed Earth at some point in its history; it would have been obliterated in a fraction of a second, Khanna said. Related: How does a black hole form?
General relativity also predicted the existence of black holes, which are regions where the spacetime torrent is so strong that nothing can escape it, not even light. It is like a cosmic one-way street: objects can fall into a black hole, but nothing can ever return.
It's not a good idea to try to enter stellar sized black hole as its event horizon is just a few kilometres long and closer to the centre of the black hole. If an astronaut enters such a black hole he will undergo what's known as Spaghettification. All the atoms of his body will be torn apart.
Black hole news: Standing on edge of black hole would cause 700 years to pass in 1 minute.
The resulting uninhabitable black hole would have such a powerful gravitational pull that not even light could avoid it. So, should you then find yourself at the event horizon — the point at which light and matter can only pass inward, as proposed by the German astronomer Karl Schwarzschild — there is no escape.
While researchers have never found a wormhole in our universe, scientists often see wormholes described in the solutions to important physics equations. Most prominently, the solutions to the equations behind Einstein's theory of space-time and general relativity include wormholes.
We might be the product of another, older universe. Call it our mother universe. The seed this mother universe forged inside a black hole may have had its big bounce 13.8 billion years ago, and even though our universe has been rapidly expanding ever since, we could still be hidden behind a black hole's event horizon.
The orbit of a black hole would have to be very close to the solar system to affect Earth, which is not likely,” NASA explained. Even the most massive black holes that are directly facing Earth aren't a threat, even though they are much larger than the sun and extremely powerful.
Black holes, the gigantic remains of collapsed stars that are massive inescapable singularities of gravity, will eventually evaporate and fade into nothingness, something that Stephen Hawking predicted. But the same fate also awaits literally everything else, a recent study suggests.
It's not exactly fast. A good size black hole — say, a few times more massive than the sun — will take about 10^100 years to eventually evaporate through this process, known as Hawking Radiation.
Cosmologists aren't sure if the universe is infinitely big or just extremely large. To measure the universe, astronomers instead look at its curvature. The geometric curve on large scales of the universe tells us about its overall shape. If the universe is perfectly geometrically flat, then it can be infinite.
Like part of a cosmic Russian doll, our universe may be nested inside a black hole that is itself part of a larger universe. In turn, all the black holes found so far in our universe—from the microscopic to the supermassive—may be doorways into alternate realities.
So far, the evidence supporting the idea of a multiverse is purely theoretical, and in some cases, philosophical. Some experts argue that it may be a grand cosmic coincidence that the big bang forged a perfectly balanced universe that is just right for our existence.
In reality, they are purely theoretical. Unlike black holes—also once thought to be purely theoretical—no evidence for an actual wormhole has ever been found, although they are fascinating from an abstract theoretical physics perceptive.
Unless the wormhole was thoroughly cleaned out and everything else blocked from entering it, falling in would mean certain death. “Whenever you travel close to the speed of light, any particle or dust grain or anything that you hit will be problematic. Even a photon would cause you trouble,” says Maldacena.
Time travel to the past is theoretically possible in certain general relativity spacetime geometries that permit traveling faster than the speed of light, such as cosmic strings, traversable wormholes, and Alcubierre drives.
Beyond the event horizon lies a truly minuscule point called a singularity, where gravity is so intense that it infinitely curves space-time itself. This is where the laws of physics, as we know them, break down, meaning all theories about what lies beyond are just speculation.
Sutter contributed this article to Space.com's Expert Voices: Op-Ed & Insights. The singularity at the center of a black hole is the ultimate no man's land: a place where matter is compressed down to an infinitely tiny point, and all conceptions of time and space completely break down. And it doesn't really exist.
Most of these are invisible to us, and only about a dozen have been identified. The nearest one is some 1,600 lightyears from Earth. In the region of the Universe visible from Earth, there are perhaps 100 billion galaxies. Each one has about 100 million stellar-mass black holes.
It is possible for two black holes to collide. Once they come so close that they cannot escape each other's gravity, they will merge to become one bigger black hole. Such an event would be extremely violent. Even when simulating this event on powerful computers, we cannot fully understand it.
There is no way a black hole would eat an entire galaxy. The gravitational reach of supermassive black holes contained in the middle of galaxies is large, but not nearly large enough for eating the whole galaxy.
The nearest known black hole is Gaia BH1, which was discovered in September 2022 by a team led by Kareem El-Badry. Gaia BH1 is 1,560 light-years away from Earth in the direction of the constellation Ophiuchus.
Practically, we cannot even imagine thinking of the end of space. It is a void where the multiverses lie. Our universe alone is expanding in every direction and covering billions of kilometres within seconds. There is infinite space where such universes roam and there is actually no end.