White holes and black holes. There’s got to be a difference, right? Besides, why would they be classified separately? So how do they compare and differ, exactly? That’s what we are going to be looking at here today.
So, what is the difference between a white hole and a black hole? The difference between a white hole and a black hole is that with a white hole, anything can escape it, but nothing can get inside. Whereas with a black hole, anything that approaches it will be drawn inside it and cannot escape.
Let’s now turn to what a white hole and then a black hole actually are.
Then we will delve into their fundamental differences in much further detail. So stick around for that.
What Is A White Hole?
A white hole is a theoretical region of spacetime that cannot be entered from the outside, although energy, matter, and light can escape from it.
A white hole has never been observed in nature but is theoretically possible according to Einstein’s General Theory of Relativity.
One theory about how a white hole might form is that it is the end state of a black hole, in which somehow gravity and time reverse themselves, and it starts emitting light, matter, and energy.
Nothing can approach a white hole past its event horizon.
Because of these facts, white holes are not thought to be long-lived if they exist.
If the theory that black holes eventually become white holes is correct, then white holes may well come to comprise the universe, perhaps trillions of times its current age in the future.
Alternatively, some scientists think that the behavior of a white hole is remarkably similar to the Big Bang, the explosion of matter and energy that created the universe.
Some scientists believe that while white holes are theoretically possible according to the math of General Relativity, they cannot exist in the physical universe.
The creation of a white hole would seem to violate entropy, which states that the universe devolves from order into chaos over time.
One metaphor offered for a white hole is the idea of an egg unscrambling itself, clearly impossible unless time can be made to flow backward.
One theory that scientists have suggested is that white holes are the missing piece of the mystery of dark matter.
Dark matter consists of 5/6 of the matter in the known universe. It cannot be seen or detected directly.
Scientists know that it exists because of its effects on celestial objects such as stars.
One theory about dark matter is that it consists of microscopic white holes, some of which predate the beginning of the universe.
Another theory suggests that white holes and black holes are somehow connected, with matter and energy that fall into a black hole emerging from a white hole, even if it is far away in space/time.
What Is A Black Hole?
Black holes are thought to be stars that have collapsed on themselves so that not even light can escape them past a point called the event horizon, which surrounds the object. Essentially, there is too much gravitational pull.
Black holes were first theorized by Einstein’s General Theory of Relativity.
They are thought to be stars that, at the end of their lives, have collapsed on themselves so that they are so heavy that they distort surrounding spacetime.
Nothing can escape from a black hole once it gets past its event horizon. Black holes can get more massive as it sucks in more matter, planets, stars, and even other black holes.
Black holes cannot be observed directly because they absorb all light. However, astronomers first discovered a black hole by observing the superheated radiation around the object orbiting a blue star 6,000 light years from Earth in the early 1970s.
Black holes can be detected by observing their effect on the matter and energy near them.
Black holes that have been created by a star’s collapse are thought to be 10 to 24 times as massive as the sun; Scientists think that ten million to a billion black holes of this type exist in the Milky Way Galaxy alone.
The center of a black hole is called a singularity, where matter is compressed to an infinitely tiny point and where the laws of space and time break down. Density becomes infinite at the singularity.
Black holes can spin. NASA has observed this phenomenon by measuring x-rays to determine how close the accretion disk, a disk of gas, particles, dust, and plasma, is to the black hole.
The faster the black hole spins, the closer the accretion disk is to it. The accretion disk consists of matter and energy that is falling into the black hole. NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) has observed the phenomenon.
Black holes have a well-deserved reputation as monsters that destroy all around them. However, the Hubble Space Telescope recently discovered a black hole in the dwarf galaxy Henize 2-10 that is creating stars rather than destroying them.
The Hubble detected a stream of super-heated gas moving from the vicinity of the black hole to a gas cloud that is a stellar nursery at a million miles an hour.
The gas stream, falling toward the black hole, is instead captured by surrounding magnetic fields and is shot outward. In theory, the gas stream is igniting star formation as it moves forth into the gas cloud.
Astronomers detected a supermassive black hole at the center of the Milky Way Galaxy, more massive than millions of stars, in the mid-1980s.
Scientists believe that every galaxy in the universe has a black hole at its center.
Scientists theorize that super-massive black holes form from super-massive stars and absorb a tremendous amount of matter and energy once they are formed.
In 2019, the Event Horizon Telescope observed the first of these black holes directly at the center of a galaxy designated M87. The image revealed a ring of superheated gas surrounding what appears to be an empty space but is the black hole’s location.
The telescope also imaged the black hole at the center of the Milky Way, designated as Sagittarius A. Scientists have learned quite a bit about the universe by comparing the two objects.
Black holes may emit a form of radiation called Hawking radiation after its discoverer, Dr. Stephen Hawking.
While not yet confirmed by observation, the idea that black holes emit radioactive particles is supported by the General Theory of Relativity and quantum mechanics.
If Hawking radiation is confirmed, then black holes would be able to emit energy and, therefore, albeit over trillions of years, could decay into white holes.
Black holes have been a feature of science fiction stories almost without number, with the better ones using their strange physics to advance the plot.
The objects have even been featured in movies to various degrees of scientific accuracy. These movies include Disney’s The Black Hole, the 2009 Star Trek feature film, and Interstellar.
What Are The Differences Between A White Hole And A Black Hole?
Observed vs. Theory
Black holes have been directly observed and measured in the universe by astronomers. White holes remain, for the time being, theoretical objects.
Absorb vs. Repel
A black hole absorbs all matter and energy that ventures past the event horizon. A white hole repels all matter and energy that ventures to its event horizon.
Scientists believe black holes are created when stars, at the end of their lives, collapse on themselves. No one knows how a white hole might be created, though one theory suggests that, eventually, black holes die and become white holes.
Escape vs. Enter
Nothing can escape beyond the event horizon of a black hole. Nothing can enter through the event horizon of a white hole.
Impact on Surroundings
A black hole is affected by its surroundings as it absorbs everything that gets too near to it. A white hole is not affected by its surroundings as it repels everything that gets too near it.
What Are The Similarities Between A White Hole And A Black Hole?
While white holes and black holes would seem to be opposites in many ways, they do have certain similarities. They both have mass. They both may spin. They both have an event horizon that separates them from the rest of the universe. Both have a ring of dust and gas around their event horizons.
Is A White Hole Stronger Than A Black Hole?
Black holes are stronger in the sense that we know they exist, as white holes are only theoretical. The scientific answer is that no one knows because white holes have never been detected, and thus their reverse gravity has never been measured to be compared to an equivalent black hole.
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Hey, my name is Chris. I’m a passionate and seasoned astronomer who loves nothing more than observing the night sky. I also love researching, learning, and writing all things Space and the Universe. I created Astronomy Scope to share my knowledge, experience, suggestions, and recommendations of what I have learned along the way while helping anyone to get into and maximize their enjoyment of the hobby.