DPM Chapter 40-Meeting Part 1
Translated by Snowfall77
Wu Xingyun was in endless darkness, the matter surrounding him distorted. Absorbed at unthinkable speed, faster than the speed of light, time warped.
Closing his eyes, Wu Xingyun knew he was about to die. His only regret was that Mozun hadn’t been able to hear Wu Xingyun’s last words.
Wu Xingyun’s body was pulled, the combat suit squeezing and cracking.
He opened his eyes back up, yet couldn’t see anything, because light did not exist in this place.
But impossibly, a twisted passage appeared before his gaze, like a thread on a conch shell, where everything around him was being thrown and squeezed. And Wu Xingyun fell straight into the twisted passage.
Wu Xingyun lost consciousness, perceiving nothing.
When he regained awareness, acute pain bombarded him. He moved his limbs, only to find himself in snow, almost bare naked. No combat suit, no Federation uniform, no compass, or any kind of communication instrument.
Feeling rather cold, Wu Xingyun struggled to sit up and looked around.
He was ringed by layers of snow and ice, with a dark sky weighing down. An apparent wasteland stretched out, murky shadows moving in the distance. Looking up, Wu Xingyun found an immense, pale yellow sun hung dimly.
What was this place? Wu Xingyun exerted all his strength, hopping and skipping through the snow. His body was still strong, and he’d received cold-exposure training, a usual skill for Ghost soldiers. Generally speaking, he could survive in a temperature of minus ten degrees without it being a significant impediment.
However, this location seemed to be chillier than minus ten degrees.
Jumping up and down in place, attempting to exorcise the frigidity, Wu Xingyun’s exhalations formed a white icy mist.
Wu Xingyun’s first direct observation was–it’s cold!
His second thought–I’m not dead yet!
And thirdly–what kind of planet it this?
After jumping in place for a while, he felt more energized, his mind concentrating on his continued survival.
Up the challenge, Wu Xingyun first searched the surrounding environment.
He found no traces of local human inhabitants. The far-off dark shadows were a species of animal, likely native to the planet, two meters tall, resembling dogs a smidge, and very strong and aggressive.
Bypassing them, Wu Xingyun finally found something in the ice and snow.
A corpse.
It wore an apparent uniform, with a coat and other warm gear, as well as an antique rifle. The uniform had no epaulettes, therefore Wu Xingyun thought the dead man should not have been in an army.
Judging from the state of the body, the man likely hadn’t been dead for more than two days, lacking the characteristics of being frozen for a longer period.
Feeling frozen himself, Wu Xingyun quickly stripped the body of clothes and whatever equipment he could find.
There was a rather backwards, simple compass, unable to indicate the coordinates of the universe, possessing only a magnetic needle.
Even the communication equipment’s range was incredibly small. Wu Xingyun tried to use it, only to discover its limited signal capacity.
Lastly was a mirror in an outmoded style. Examining the script on the objects, Wu Xingyun guessed that he was in Demon Army territory.
After donning the newly acquired clothing, Wu Xingyun finally felt a bit more comfortable. He took a few bites of snow, checked the weapons he’d obtained, and explored the surrounding area once again.
He found thirty-two more bodies, dressed in identical clothes, equipped with the same weapons.
Based on the few texts he collected, Wu Xingyun surmised that they were an expedition team sent by Mozun, even though he’d never heard Mozun mention such troops.
It didn’t matter. Gazing up at the night sky, Wu Xingyun could easily identify some of the stars. Iconic constellations hung in the sky, presumably confirming Wu Xingyun’s location—in Demon Army domains, near the vicinity of the legendary Earth.
How had Wu Xingyun come here??
Wu Xingyun had no idea. It was a question he couldn’t answer, so he stuck to simpler objectives. First, he’d find a living person, ask for specific coordinates, and then obtain communication equipment.
Even after determining this plan, Wu Xingyun couldn’t help feeling perplexed. Say he did get the communication equipment, who should he go to? Return to the Federation, or find Mozun?
He was in Mozun’s sphere of influence. Did Wu Xingyun want to find Mozun?
Inwardly, Wu Xingyun thought ‘no.’ Until he remembered Mozun tightly clasping onto himself, refusing to let go. A burst of bewilderment hit Wu Xingyun’s heart.
Setting it aside, Wu Xingyun didn’t dwell on it. Finding a living person was the more pressing problem.
Wu Xingyun stared at the scenery, unsure of what direction he should go in. A vast white expanse stretched out, nothing distinguishing a possible route.
The huge faded orb sat on the horizon, Wu Xingyun realizing it wasn’t a fixed star, but a close satellite. The distance was short, even though it wasn’t emitting heat.
Judging by its rays, Wu Xingyun guessed that this planet should have fixed stars. Otherwise the satellite in the sky wouldn’t glow in the darkness.
In other words, it wouldn’t always be night. There would be day.
Wu Xingyun decided to rest where he was at. Daylight would allow him to survey his surroundings better.
Before too long, dawn arrived. Wu Xingyun took a dagger he’d found, made a hole in the ground, and inserted equipment that would observe the relationship between the planet and its sun.
And began to calculate.
Thanks to his Federation elementary school education, surveying his location, along with calculating the distance and orbit of the stars above, was a simple task for Wu Xingyun.
Soon enough, he figured out the planet’s orbital revolution and rotation period, using shadow measurement and trigonometry.
Examining his collected data, a strange feeling came over Wu Xingyun. His data basically matched the textbook data about Earth, the birthplace of humanity.
One sun during the day. A moon at night.
Where the hell was he? If it was the planet Earth, didn’t the history books say that Earth had been completely destroyed after a large-scale nuclear explosion? How could there still be signs of life?
""
Filled with misgivings, Wu Xingyun, carrying the rifle, marched towards what he estimated might be a human gathering point.
As he passed the huge animals, they tried to attack.
Wu Xingyun shot one through the eye. The fur wasn’t easily skinned off, though Wu Xingyun found the meat delicious.
He did take a piece of the hide, putting it in his backpack, planning on putting it under his body when he slept at night.
Moving forward during the day, resting at night, Wu Xingyun encountered many strong creatures, while also occasionally happening upon human corpses.
The dead bodies were dressed like the ones he’d first chanced upon, however these uniforms had epaulettes. Wu Xingyun assumed the epaulettes indicted their military rank. Still, the ranks matched neither the Federation or the Alliance. They looked like soldiers to Wu Xingyun, but he felt if they were soldiers, they shouldn’t have died on such a large scale. Moreover……The equipment was so sub-standard, whoever was on the planet must be dangerous. Arming soldiers with such worthless weapons and equipment necessary for their survival was tantamount to letting them die.
When Wu Xingyun inspected their physical condition, he found them inadequate in that area too.
They didn’t compare to ordinary soldiers of the Federation, not even ordinary soldiers of the Alliance. To verify it to himself, Wu Xingyun dissected one corpse, removing the internal organs.
The heart was smaller than an average person’s. All the organs appeared underdeveloped. They weren’t so much soldiers as they were unevolved humans.
Wu Xingyun found everything around him bewildering. Ten days later, he finally found something similar to a man-made road, albeit unsophisticated and not particularly durable. Unsurprisingly, it was badly damaged.
Frowning, Wu Xingyun scratched his head and started walking along it.
Pressing on, Wu Xingyun saw more bodies, men and women, apparently regular citizens since they weren’t wearing uniforms, although their clothing style was exceedingly old-fashioned.
Searching the bodies, Wu Xingyun recovered an altitude tester, to find that he was at an elevation of more than five thousand meters above sea level.
However, since the altitude tester didn’t identify the benchmark, Wu Xingyun was still at a loss.
Orbital revolution is the movement of a planet around a star, or a moon around a planet. For example, the Earth revolves around the Sun, and the Moon revolves about the Earth.
Planets and moons revolve in elliptical orbits. One orbital revolution of a planet takes one year, while a revolution of the Moon takes a month.
https://simple.wikipedia.org/wiki/Orbital_revolution
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) is the time that the object takes to complete a single revolution around its axis of rotation relative to the background stars. It differs from the object’s solar day, which may differ by a fractional rotation to accommodate the portion of the object’s orbital period during one day.
https://en.wikipedia.org/wiki/Rotation_period
Epaulette (/ˈɛpəlɛt/; also spelled epaulet)[1] is a type of ornamental shoulder piece or decoration used as insignia of rank by armed forces and other organizations. In the French and other armies, epaulettes are also worn by all ranks of elite or ceremonial units when on parade. It may bear rank or other insignia, and should not be confused with a shoulder mark – also called a shoulder board, rank slide, or slip-on – a flat cloth sleeve worn on the shoulder strap of a uniform (although the two terms are often used interchangeably).[2]
https://en.wikipedia.org/wiki/Epaulette
Fixed stars
The fixed stars (Latin: stellae fixae) comprise the background of astronomical objects that appear to not move relative to each other in the night sky compared to the foreground of Solar System objects that do. Generally, the fixed stars are taken to include all stars other than the Sun. Nebulae and other deep-sky objects may also be counted among the fixed stars.
Exact delimitation of the term is complicated by the fact that no celestial objects are in fact fixed with respect to each other. Nonetheless, extrasolar objects move so slowly in the sky that the change in their relative positions is nearly imperceptible on typical human timescales, except to careful examination, and thus can be considered “fixed” for many purposes. Furthermore, distant stars and galaxies move even slower in the sky than comparatively closer ones.
People in many cultures have imagined that the stars form pictures in the sky called constellations. In Ancient Greek astronomy, the fixed stars were believed to exist on a giant celestial sphere, or firmament, that revolves daily around Earth.
https://en.wikipedia.org/wiki/Fixed_stars
Black holes are so massive that they severely warp the fabric of spacetime (the three spatial dimensions and time combined in a four-dimensional continuum). For this reason, an observer inside a black hole experiences the passage of time much differently than an outside observer. Imagine you want to investigate a black hole by shining a light towards it and measuring the time that elapses before the light is reflected back to you. Unfortunately, you will be waiting a very long time—forever, in fact. The light will appear to continually slow down as it approaches the black hole, ultimately reaching a complete dead stop at the event horizon.
Now imagine your colleague Sally is interested in more hands-on investigation of time inside a black hole, and decides to dive towards it. Before she leaves, Sally agrees to flash a light back to you every second. From your perspective, Sally appears to slow down as she approaches the black hole, and the time interval between her flashes of light gradually increases. Additionally, the light she sends back to you gradually gets dimmer and redder.
According to your perspective, Sally never actually descends into the black hole; she will travel more and more slowly as she approaches the event horizon, but you will never actually see her reach “the point of no return.” Time comes to a standstill at the event horizon, such that an outside observer will never really see anything fall inside a black hole.
How is Time Changed Inside a Black Hole?
What happens to time inside a black hole?
Answered July 12, 2017 · Author has 3.7K answers and 8.3M answer views
Originally Answered: what happens to time inside a black hole?
Short answer: Nothing happens to time inside a black hole.
No one knows exactly what TIME is. One thing we do know is that time is not tangible, and it is not ‘moving’. Time just IS – and everything in the universe is moving through time. If you accept this, then you will agree that time cannot ‘slow down’ or ‘speed up’.
Modern Philosophy
A clock slows down near any massive body; black holes are merely the most extreme example. Black holes are so massive that they severely warp the fabric of spacetime. Because of this, according to theory, an observer inside a black hole will experience the ‘passage of time’ much differently than an observer outside. Scientists do not have the physics to describe the inside of black holes, so they can only speculate as to what happens right at the edge of the black hole.
……
Time does not actually ‘stop’ or ‘freeze’ inside a black hole. Time simply goes on. Even for observers outside the black hole “looking in”, time does not stop. Instead, the ‘passage of time’ slows down to a crawl. Time keeps ticking away, but it is slow: It is so slow that it would take an infinite amount of time before the outside observer can see someone actually fall in. The fact that it takes an infinite time however does not mean that time stops. (I use the word ‘infinite’ to mean something limitless or endless in space, extent, or size; impossible to measure or calculate). The object going into the black hole, however, experiences no strange effects and does, in fact, pass through the horizon normally, in a finite amount of proper time. (In fact, the actual time taken, if the black hole has a mass of 5 millions suns, – approximately equal to the mass of the supermassive black hole at the center of our Galaxy – is only 16 seconds to fall from the horizon to the singularity.)**
Singularities and Black Holes
Just last year, researchers from the University of California, USA published a paper in which they claim a new area law in general relativity that is based on an interpretation of black holes as curved geometric objects called “holographic screens.” According to them, Holographic screens are in a sense a local boundary to regions of strong gravitational fields, and “Future holographic screens” correspond to gravitational fields which pull matter together such as black holes, whereas “past holographic screens” correspond to regions which spread matter out such as the big bang.
According to the holographic principle, the amount of information or entropy in a given area is related to the surface area. So by interpreting the area as a bound on the entropy, the area law can reveal the direction of thermodynamic time (which, as the scientists note, is not the same as mathematical time). Because the area of future and past holographic screens increases in different directions, the direction of time is different for the two types of screens. In past screens, time moves forward. Expanding universes, such as ours, involve past holographic screens, and so we naturally perceive thermodynamic time as running forward. In contrast, time runs backward in future holographic screens. In a sense, this interpretation has the odd result that thermodynamic time runs backward inside black holes and collapsing universes.
Answered July 15, 2017 · Author has 3K answers and 3.7M answer views
Originally Answered: How does black hole affect time?
How does black hole affect time?
Any gravitational field causes time to run more slowly at a lower point in it. This may even be used as a definition of “down” and “lower”, which agrees with our intuitive understanding of the words. (Since I just posted a sort-of explanation of why/how, I won’t repeat it here.)
A feature of a black hole is that it has an “event horizon” as seen by a distant observer. For present purposes, I shall suppose that that distant observer is on Earth. An event horizon is the surface where the difference in depth in the gravitational field, between the observer and the surface, is so great that, from the observer’s point of view, time is completely stopped at that surface.
Consequently, from the observer’s point of view, time for an object falling into the gravitational field gradually slows down. A clock on the falling object, visible to the observer, would be seen to approach a complete stop as the object approached the event horizon, and the falling object would be seen to slow down correspondingly, in spite of the gravitational field accelerating it downward. No matter how long the observer keeps watching, she/he would never see the object reach the event horizon.
This deceleration is true even for infalling light. Thus, the information carried by light passing toward the event horizon is concentrated in an infinitesimally thin shell over the event horizon, from the point of view of the Earth-bound observer.
Correspondingly, no matter how fast an object moves upward from the event horizon, even light at the speed of light, it will never reach the observer. That is what makes the black hole black.
From the point of view of an observer dropping into the black hole, time at the location of the above-mentioned Earth-bound observer seems to flow faster, reciprocally to the Earth-bound observer’s perception. Since Earth is at an average sort of location in the Universe, the in-falling observer perceives most of the Universe to be running faster.
The infalling observer reaches the calculated location of the event horizon within a finite time from its point of view. I say the “calculated” position, because the infalling observer perceives time in his/her vicinity to be much like anywhere else. But as the Earth-bound observer perceives time on the infalling object coming to a stop, the infalling observer perceives time in most of the Universe to be approaching an infinite rate. As the infalling observer reaches the calculated location of the event horizon, she/he witnesses the entire history of the Universe.
Information carried by light from the rest of the Universe, from the point of view of an observer at the calculated position of the event horizon, keeps propagating inward at the speed of light, because light always propagates at that speed as measured at any location. While an Earth-bound observer perceives the information to be concentrated in an infinitesimal skin, the information goes right on in from a local point of view. The contrast between these two points of view is called the “holographic principle”.
Since the gravitational field of a black hole has infinite depth, the infalling observer always perceives an event horizon between himself/herself and the central singularity, until the observer reaches the central singularity.
What happens at the central singularity is not known, not even according to any credible theory.
The above sequence of events is only theoretical, because not only is the gravitational field at the singularity infinite, but so is the gradient of the field. Therefore, any material observer will be torn apart before reaching the singularity.
DPM Chapter 40-Meeting Part 1
Translated by Snowfall77
Wu Xingyun was in endless darkness, the matter surrounding him distorted. Absorbed at unthinkable speed, faster than the speed of light, time warped.
Closing his eyes, Wu Xingyun knew he was about to die. His only regret was that Mozun hadn’t been able to hear Wu Xingyun’s last words.
Wu Xingyun’s body was pulled, the combat suit squeezing and cracking.
He opened his eyes back up, yet couldn’t see anything, because light did not exist in this place.
But impossibly, a twisted passage appeared before his gaze, like a thread on a conch shell, where everything around him was being thrown and squeezed. And Wu Xingyun fell straight into the twisted passage.
Wu Xingyun lost consciousness, perceiving nothing.
When he regained awareness, acute pain bombarded him. He moved his limbs, only to find himself in snow, almost bare naked. No combat suit, no Federation uniform, no compass, or any kind of communication instrument.
Feeling rather cold, Wu Xingyun struggled to sit up and looked around.
He was ringed by layers of snow and ice, with a dark sky weighing down. An apparent wasteland stretched out, murky shadows moving in the distance. Looking up, Wu Xingyun found an immense, pale yellow sun hung dimly.
What was this place? Wu Xingyun exerted all his strength, hopping and skipping through the snow. His body was still strong, and he’d received cold-exposure training, a usual skill for Ghost soldiers. Generally speaking, he could survive in a temperature of minus ten degrees without it being a significant impediment.
However, this location seemed to be chillier than minus ten degrees.
Jumping up and down in place, attempting to exorcise the frigidity, Wu Xingyun’s exhalations formed a white icy mist.
Wu Xingyun’s first direct observation was–it’s cold!
His second thought–I’m not dead yet!
And thirdly–what kind of planet it this?
After jumping in place for a while, he felt more energized, his mind concentrating on his continued survival.
Up the challenge, Wu Xingyun first searched the surrounding environment.
He found no traces of local human inhabitants. The far-off dark shadows were a species of animal, likely native to the planet, two meters tall, resembling dogs a smidge, and very strong and aggressive.
Bypassing them, Wu Xingyun finally found something in the ice and snow.
A corpse.
It wore an apparent uniform, with a coat and other warm gear, as well as an antique rifle. The uniform had no epaulettes, therefore Wu Xingyun thought the dead man should not have been in an army.
Judging from the state of the body, the man likely hadn’t been dead for more than two days, lacking the characteristics of being frozen for a longer period.
Feeling frozen himself, Wu Xingyun quickly stripped the body of clothes and whatever equipment he could find.
There was a rather backwards, simple compass, unable to indicate the coordinates of the universe, possessing only a magnetic needle.
Even the communication equipment’s range was incredibly small. Wu Xingyun tried to use it, only to discover its limited signal capacity.
Lastly was a mirror in an outmoded style. Examining the script on the objects, Wu Xingyun guessed that he was in Demon Army territory.
After donning the newly acquired clothing, Wu Xingyun finally felt a bit more comfortable. He took a few bites of snow, checked the weapons he’d obtained, and explored the surrounding area once again.
He found thirty-two more bodies, dressed in identical clothes, equipped with the same weapons.
Based on the few texts he collected, Wu Xingyun surmised that they were an expedition team sent by Mozun, even though he’d never heard Mozun mention such troops.
It didn’t matter. Gazing up at the night sky, Wu Xingyun could easily identify some of the stars. Iconic constellations hung in the sky, presumably confirming Wu Xingyun’s location—in Demon Army domains, near the vicinity of the legendary Earth.
How had Wu Xingyun come here??
Wu Xingyun had no idea. It was a question he couldn’t answer, so he stuck to simpler objectives. First, he’d find a living person, ask for specific coordinates, and then obtain communication equipment.
Even after determining this plan, Wu Xingyun couldn’t help feeling perplexed. Say he did get the communication equipment, who should he go to? Return to the Federation, or find Mozun?
He was in Mozun’s sphere of influence. Did Wu Xingyun want to find Mozun?
Inwardly, Wu Xingyun thought ‘no.’ Until he remembered Mozun tightly clasping onto himself, refusing to let go. A burst of bewilderment hit Wu Xingyun’s heart.
Setting it aside, Wu Xingyun didn’t dwell on it. Finding a living person was the more pressing problem.
Wu Xingyun stared at the scenery, unsure of what direction he should go in. A vast white expanse stretched out, nothing distinguishing a possible route.
The huge faded orb sat on the horizon, Wu Xingyun realizing it wasn’t a fixed star, but a close satellite. The distance was short, even though it wasn’t emitting heat.
Judging by its rays, Wu Xingyun guessed that this planet should have fixed stars. Otherwise the satellite in the sky wouldn’t glow in the darkness.
In other words, it wouldn’t always be night. There would be day.
Wu Xingyun decided to rest where he was at. Daylight would allow him to survey his surroundings better.
Before too long, dawn arrived. Wu Xingyun took a dagger he’d found, made a hole in the ground, and inserted equipment that would observe the relationship between the planet and its sun.
And began to calculate.
Thanks to his Federation elementary school education, surveying his location, along with calculating the distance and orbit of the stars above, was a simple task for Wu Xingyun.
Soon enough, he figured out the planet’s orbital revolution and rotation period, using shadow measurement and trigonometry.
Examining his collected data, a strange feeling came over Wu Xingyun. His data basically matched the textbook data about Earth, the birthplace of humanity.
One sun during the day. A moon at night.
Where the hell was he? If it was the planet Earth, didn’t the history books say that Earth had been completely destroyed after a large-scale nuclear explosion? How could there still be signs of life?
""
Filled with misgivings, Wu Xingyun, carrying the rifle, marched towards what he estimated might be a human gathering point.
As he passed the huge animals, they tried to attack.
Wu Xingyun shot one through the eye. The fur wasn’t easily skinned off, though Wu Xingyun found the meat delicious.
He did take a piece of the hide, putting it in his backpack, planning on putting it under his body when he slept at night.
Moving forward during the day, resting at night, Wu Xingyun encountered many strong creatures, while also occasionally happening upon human corpses.
The dead bodies were dressed like the ones he’d first chanced upon, however these uniforms had epaulettes. Wu Xingyun assumed the epaulettes indicted their military rank. Still, the ranks matched neither the Federation or the Alliance. They looked like soldiers to Wu Xingyun, but he felt if they were soldiers, they shouldn’t have died on such a large scale. Moreover……The equipment was so sub-standard, whoever was on the planet must be dangerous. Arming soldiers with such worthless weapons and equipment necessary for their survival was tantamount to letting them die.
When Wu Xingyun inspected their physical condition, he found them inadequate in that area too.
They didn’t compare to ordinary soldiers of the Federation, not even ordinary soldiers of the Alliance. To verify it to himself, Wu Xingyun dissected one corpse, removing the internal organs.
The heart was smaller than an average person’s. All the organs appeared underdeveloped. They weren’t so much soldiers as they were unevolved humans.
Wu Xingyun found everything around him bewildering. Ten days later, he finally found something similar to a man-made road, albeit unsophisticated and not particularly durable. Unsurprisingly, it was badly damaged.
Frowning, Wu Xingyun scratched his head and started walking along it.
Pressing on, Wu Xingyun saw more bodies, men and women, apparently regular citizens since they weren’t wearing uniforms, although their clothing style was exceedingly old-fashioned.
Searching the bodies, Wu Xingyun recovered an altitude tester, to find that he was at an elevation of more than five thousand meters above sea level.
However, since the altitude tester didn’t identify the benchmark, Wu Xingyun was still at a loss.
Orbital revolution is the movement of a planet around a star, or a moon around a planet. For example, the Earth revolves around the Sun, and the Moon revolves about the Earth.
Planets and moons revolve in elliptical orbits. One orbital revolution of a planet takes one year, while a revolution of the Moon takes a month.
https://simple.wikipedia.org/wiki/Orbital_revolution
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) is the time that the object takes to complete a single revolution around its axis of rotation relative to the background stars. It differs from the object’s solar day, which may differ by a fractional rotation to accommodate the portion of the object’s orbital period during one day.
https://en.wikipedia.org/wiki/Rotation_period
Epaulette (/ˈɛpəlɛt/; also spelled epaulet)[1] is a type of ornamental shoulder piece or decoration used as insignia of rank by armed forces and other organizations. In the French and other armies, epaulettes are also worn by all ranks of elite or ceremonial units when on parade. It may bear rank or other insignia, and should not be confused with a shoulder mark – also called a shoulder board, rank slide, or slip-on – a flat cloth sleeve worn on the shoulder strap of a uniform (although the two terms are often used interchangeably).[2]
https://en.wikipedia.org/wiki/Epaulette
Fixed stars
The fixed stars (Latin: stellae fixae) comprise the background of astronomical objects that appear to not move relative to each other in the night sky compared to the foreground of Solar System objects that do. Generally, the fixed stars are taken to include all stars other than the Sun. Nebulae and other deep-sky objects may also be counted among the fixed stars.
Exact delimitation of the term is complicated by the fact that no celestial objects are in fact fixed with respect to each other. Nonetheless, extrasolar objects move so slowly in the sky that the change in their relative positions is nearly imperceptible on typical human timescales, except to careful examination, and thus can be considered “fixed” for many purposes. Furthermore, distant stars and galaxies move even slower in the sky than comparatively closer ones.
People in many cultures have imagined that the stars form pictures in the sky called constellations. In Ancient Greek astronomy, the fixed stars were believed to exist on a giant celestial sphere, or firmament, that revolves daily around Earth.
https://en.wikipedia.org/wiki/Fixed_stars
Black holes are so massive that they severely warp the fabric of spacetime (the three spatial dimensions and time combined in a four-dimensional continuum). For this reason, an observer inside a black hole experiences the passage of time much differently than an outside observer. Imagine you want to investigate a black hole by shining a light towards it and measuring the time that elapses before the light is reflected back to you. Unfortunately, you will be waiting a very long time—forever, in fact. The light will appear to continually slow down as it approaches the black hole, ultimately reaching a complete dead stop at the event horizon.
Now imagine your colleague Sally is interested in more hands-on investigation of time inside a black hole, and decides to dive towards it. Before she leaves, Sally agrees to flash a light back to you every second. From your perspective, Sally appears to slow down as she approaches the black hole, and the time interval between her flashes of light gradually increases. Additionally, the light she sends back to you gradually gets dimmer and redder.
According to your perspective, Sally never actually descends into the black hole; she will travel more and more slowly as she approaches the event horizon, but you will never actually see her reach “the point of no return.” Time comes to a standstill at the event horizon, such that an outside observer will never really see anything fall inside a black hole.
How is Time Changed Inside a Black Hole?
What happens to time inside a black hole?
Answered July 12, 2017 · Author has 3.7K answers and 8.3M answer views
Originally Answered: what happens to time inside a black hole?
Short answer: Nothing happens to time inside a black hole.
No one knows exactly what TIME is. One thing we do know is that time is not tangible, and it is not ‘moving’. Time just IS – and everything in the universe is moving through time. If you accept this, then you will agree that time cannot ‘slow down’ or ‘speed up’.
Modern Philosophy
A clock slows down near any massive body; black holes are merely the most extreme example. Black holes are so massive that they severely warp the fabric of spacetime. Because of this, according to theory, an observer inside a black hole will experience the ‘passage of time’ much differently than an observer outside. Scientists do not have the physics to describe the inside of black holes, so they can only speculate as to what happens right at the edge of the black hole.
……
Time does not actually ‘stop’ or ‘freeze’ inside a black hole. Time simply goes on. Even for observers outside the black hole “looking in”, time does not stop. Instead, the ‘passage of time’ slows down to a crawl. Time keeps ticking away, but it is slow: It is so slow that it would take an infinite amount of time before the outside observer can see someone actually fall in. The fact that it takes an infinite time however does not mean that time stops. (I use the word ‘infinite’ to mean something limitless or endless in space, extent, or size; impossible to measure or calculate). The object going into the black hole, however, experiences no strange effects and does, in fact, pass through the horizon normally, in a finite amount of proper time. (In fact, the actual time taken, if the black hole has a mass of 5 millions suns, – approximately equal to the mass of the supermassive black hole at the center of our Galaxy – is only 16 seconds to fall from the horizon to the singularity.)**
Singularities and Black Holes
Just last year, researchers from the University of California, USA published a paper in which they claim a new area law in general relativity that is based on an interpretation of black holes as curved geometric objects called “holographic screens.” According to them, Holographic screens are in a sense a local boundary to regions of strong gravitational fields, and “Future holographic screens” correspond to gravitational fields which pull matter together such as black holes, whereas “past holographic screens” correspond to regions which spread matter out such as the big bang.
According to the holographic principle, the amount of information or entropy in a given area is related to the surface area. So by interpreting the area as a bound on the entropy, the area law can reveal the direction of thermodynamic time (which, as the scientists note, is not the same as mathematical time). Because the area of future and past holographic screens increases in different directions, the direction of time is different for the two types of screens. In past screens, time moves forward. Expanding universes, such as ours, involve past holographic screens, and so we naturally perceive thermodynamic time as running forward. In contrast, time runs backward in future holographic screens. In a sense, this interpretation has the odd result that thermodynamic time runs backward inside black holes and collapsing universes.
Answered July 15, 2017 · Author has 3K answers and 3.7M answer views
Originally Answered: How does black hole affect time?
How does black hole affect time?
Any gravitational field causes time to run more slowly at a lower point in it. This may even be used as a definition of “down” and “lower”, which agrees with our intuitive understanding of the words. (Since I just posted a sort-of explanation of why/how, I won’t repeat it here.)
A feature of a black hole is that it has an “event horizon” as seen by a distant observer. For present purposes, I shall suppose that that distant observer is on Earth. An event horizon is the surface where the difference in depth in the gravitational field, between the observer and the surface, is so great that, from the observer’s point of view, time is completely stopped at that surface.
Consequently, from the observer’s point of view, time for an object falling into the gravitational field gradually slows down. A clock on the falling object, visible to the observer, would be seen to approach a complete stop as the object approached the event horizon, and the falling object would be seen to slow down correspondingly, in spite of the gravitational field accelerating it downward. No matter how long the observer keeps watching, she/he would never see the object reach the event horizon.
This deceleration is true even for infalling light. Thus, the information carried by light passing toward the event horizon is concentrated in an infinitesimally thin shell over the event horizon, from the point of view of the Earth-bound observer.
Correspondingly, no matter how fast an object moves upward from the event horizon, even light at the speed of light, it will never reach the observer. That is what makes the black hole black.
From the point of view of an observer dropping into the black hole, time at the location of the above-mentioned Earth-bound observer seems to flow faster, reciprocally to the Earth-bound observer’s perception. Since Earth is at an average sort of location in the Universe, the in-falling observer perceives most of the Universe to be running faster.
The infalling observer reaches the calculated location of the event horizon within a finite time from its point of view. I say the “calculated” position, because the infalling observer perceives time in his/her vicinity to be much like anywhere else. But as the Earth-bound observer perceives time on the infalling object coming to a stop, the infalling observer perceives time in most of the Universe to be approaching an infinite rate. As the infalling observer reaches the calculated location of the event horizon, she/he witnesses the entire history of the Universe.
Information carried by light from the rest of the Universe, from the point of view of an observer at the calculated position of the event horizon, keeps propagating inward at the speed of light, because light always propagates at that speed as measured at any location. While an Earth-bound observer perceives the information to be concentrated in an infinitesimal skin, the information goes right on in from a local point of view. The contrast between these two points of view is called the “holographic principle”.
Since the gravitational field of a black hole has infinite depth, the infalling observer always perceives an event horizon between himself/herself and the central singularity, until the observer reaches the central singularity.
What happens at the central singularity is not known, not even according to any credible theory.
The above sequence of events is only theoretical, because not only is the gravitational field at the singularity infinite, but so is the gradient of the field. Therefore, any material observer will be torn apart before reaching the singularity.
