Back in the 1980s, astronomers spotted a runaway star speeding across the night sky at upwards of 1.2 million miles per hour. Now, decades later, scientists say they've finally figured out which pocket of the galaxy the star once called home — and what it's fleeing from: a
In May 2022, scientists revealed the historic first image of the supermassive black hole at the center of our galaxy — Sagitarrius A*.
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?
Black holes are dark, dense regions in space where the pull of gravity is so strong that nothing can escape. Not even light can get out of these regions. That is why we cannot see black holes—they are invisible to our eyes. Because nothing can get out of black holes, physicists struggle understanding these objects.
Fortunately, this has never happened to anyone — black holes are too far away to pull in any matter from our solar system.
Since nothing can escape from the gravitational force of a black hole, it was long thought that black holes are impossible to destroy. But we now know that black holes actually evaporate, slowly returning their energy to the Universe.
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.
The two black holes lie just 1,560 and 3,800 light-years from our planet, respectively. Astronomers have discovered two new black holes that are the closest ones to Earth known, and also represent something that astronomers have never seen before.
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.
Near a black hole, the slowing of time is extreme. From the viewpoint of an observer outside the black hole, time stops. For example, an object falling into the hole would appear frozen in time at the edge of the hole. Inside a black hole is where the real mystery lies.
Stellar-mass black holes are found throughout our Milky Way galaxy and have masses less than about 100 times that of our Sun. They comprise one of the possible endpoints of the lives of high-mass stars.
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.
Once you're past the event horizon things would get really grim. If you were heading towards the centre of the black hole feet first, the gravitational pull on your feet would be a lot stronger than the gravitational pull on your head. You'd get stretched and squished like spaghetti.
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.
For most space objects, we use light-years to describe their distance. A light-year is the distance light travels in one Earth year. One light-year is about 6 trillion miles (9 trillion km). That is a 6 with 12 zeros behind it!
In the next three years, a once-in-history astronomical event is expected to occur: two massive black holes will collide and merge to form a single black hole, with the point of convergence set to be visible from ground-based observatories. Simulation showing a pair of black holes about to merge.
As their extended cosmic duet progresses, the pair will draw even closer together as surrounding swarms of stars and gas siphon away their orbital momentum. The authors predict that the dance will end in approximately 200 million years, when the two supermassive black holes at last fully merge to become one.
Wormholes are possible, according to Einstein's general theory of relativity, but nobody has ever spotted one.
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.
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.
If the density of matter in the universe is high enough, its gravity could overcome the expansion and trigger a contraction phase instead. Everything will begin to move towards everything else as the universe shrinks once again.
Its mass, M, is its sensitivity to gravity. So Q > M means gravity is the weaker of the two. From their assumption that black holes ought to be able to decay, the four physicists made a more sweeping conjecture that gravity must be the weakest force in any viable universe.
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.
When it starts to die, the Sun will expand into a red giant star, becoming so large that it will engulf Mercury and Venus, and possibly Earth as well. Scientists predict the Sun is a little less than halfway through its lifetime and will last another 5 billion years or so before it becomes a white dwarf.