Escape velocity and Speed of light?

Why is the speed of light constant in all frames of reference when the speed of light is much greater than the escape velocity of any celestial body except the black hole?
Any special reason.

Why is the speed of light constant in all frames of reference when the speed of light is much greater than the escape velocity of any celestial body except the black hole?
Any special reason.

Simply because black holes are far more massive than most celestial bodies we are familiar with in our solar system. Bigger objects have larger escape velocities, and if it's big enough that velocity becomes greater than the speed of light.

In reality, there are bodies of all sizes in our galaxy and the universe. From dust to grains of sand to rocks and asteroids, small planets like Earth, large planets like Jupiter, small Suns like ours, to massive stars 800 times bigger than ours, to small black holes, to huge black holes like in the center of our galaxy.

A black hole is simply what we call ANY object that is so heavy it's escape velocity is greater than the speed of light. Once that happens it is now a black hole, as we can't see what goes on inside.

Quote from: E E K on June 21, 2020, 02:41:03 AM

Why is the speed of light constant in all frames of reference when the speed of light is much greater than the escape velocity of any celestial body except the black hole?
Any special reason.

Simply because black holes are far more massive than most celestial bodies we are familiar with in our solar system. Bigger objects have larger escape velocities, and if it's big enough that velocity becomes greater than the speed of light.

In reality, there are bodies of all sizes in our galaxy and the universe. From dust to grains of sand to rocks and asteroids, small planets like Earth, large planets like Jupiter, small Suns like ours, to massive stars 800 times bigger than ours, to small black holes, to huge black holes like in the center of our galaxy.

A black hole is simply what we call ANY object that is so heavy it's escape velocity is greater than the speed of light. Once that happens it is now a black hole, as we can't see what goes on inside.

Electromagnetic Radiation has no mass.
How is it effected by gravity?

Gravitation is bend space time thus light can be effected by it.

Quote from: JJA on June 21, 2020, 04:15:40 AM

Quote from: E E K on June 21, 2020, 02:41:03 AM

Why is the speed of light constant in all frames of reference when the speed of light is much greater than the escape velocity of any celestial body except the black hole?
Any special reason.

Simply because black holes are far more massive than most celestial bodies we are familiar with in our solar system. Bigger objects have larger escape velocities, and if it's big enough that velocity becomes greater than the speed of light.

In reality, there are bodies of all sizes in our galaxy and the universe. From dust to grains of sand to rocks and asteroids, small planets like Earth, large planets like Jupiter, small Suns like ours, to massive stars 800 times bigger than ours, to small black holes, to huge black holes like in the center of our galaxy.

A black hole is simply what we call ANY object that is so heavy it's escape velocity is greater than the speed of light. Once that happens it is now a black hole, as we can't see what goes on inside.

Electromagnetic Radiation has no mass.
How is it effected by gravity?

escape velocity is independent of falling mass, here is the formula
https://www.toppr.com/guides/physics-formulas/escape-velocity-formula/#:~:text=The%20formula%20for%20escape%20velocity,second%20(m%2Fs).

Quote from: Bullwinkle on June 21, 2020, 02:30:43 PM

Quote from: JJA on June 21, 2020, 04:15:40 AM

Quote from: E E K on June 21, 2020, 02:41:03 AM

Why is the speed of light constant in all frames of reference when the speed of light is much greater than the escape velocity of any celestial body except the black hole?
Any special reason.

Simply because black holes are far more massive than most celestial bodies we are familiar with in our solar system. Bigger objects have larger escape velocities, and if it's big enough that velocity becomes greater than the speed of light.

In reality, there are bodies of all sizes in our galaxy and the universe. From dust to grains of sand to rocks and asteroids, small planets like Earth, large planets like Jupiter, small Suns like ours, to massive stars 800 times bigger than ours, to small black holes, to huge black holes like in the center of our galaxy.

A black hole is simply what we call ANY object that is so heavy it's escape velocity is greater than the speed of light. Once that happens it is now a black hole, as we can't see what goes on inside.

Electromagnetic Radiation has no mass.
How is it effected by gravity?

escape velocity is independent of falling mass, here is the formula
https://www.toppr.com/guides/physics-formulas/escape-velocity-formula/#:~:text=The%20formula%20for%20escape%20velocity,second%20(m%2Fs).

Are you claiming that the speed of light varies with gravity?

Are you claiming that the speed of light varies with gravity?

I don't know about E E K but Einstein does "claim that the speed of light varies with gravity" with gravitational potential to be more precise.

Apparent correction to the speed of light in a gravitational potential
Einstein was the first to predict that the velocity of light would be reduced by a gravitational potential [37]. According to general relativity [38, 39], the speed of light c₀ as measured in a global reference frame is given by

                                       

where c₀ is the speed of light as measured in a local freely-falling reference frame. This reduction in the speed of light can be observed if a beam of light passes near a massive object such as the Sun, as illustrated in figure 1. The transit time from a distant planet or satellite to Earth can be measured as a function of the distance, D, of closest approach to the Sun and then compared to the transit time expected at a velocity of c₀. The results from such experiments are in excellent agreement with the prediction of equation (1).


Figure 1. A measurement of the transit time at the speed of light from a distant satellite to Earth. Einstein predicted that the speed of light as measured in a global reference frame would be reduced by the gravitational potential of the Sun as described by equation (1), which is in good agreement with experiments. Here D is the distance of closest approach. The deflection of the light beam by the gravitational potential of the Sun is very small and is not illustrated here.

Quote from: Bullwinkle on June 21, 2020, 03:24:05 PM

Are you claiming that the speed of light varies with gravity?

I don't know about E E K but Einstein does "claim that the speed of light varies with gravity" with gravitational potential to be more precise.

Quote from: J D Franson

Apparent correction to the speed of light in a gravitational potential
Einstein was the first to predict that the velocity of light would be reduced by a gravitational potential [37]. According to general relativity [38, 39], the speed of light c₀ as measured in a global reference frame is given by

                                       

where c₀ is the speed of light as measured in a local freely-falling reference frame. This reduction in the speed of light can be observed if a beam of light passes near a massive object such as the Sun, as illustrated in figure 1. The transit time from a distant planet or satellite to Earth can be measured as a function of the distance, D, of closest approach to the Sun and then compared to the transit time expected at a velocity of c₀. The results from such experiments are in excellent agreement with the prediction of equation (1).


Figure 1. A measurement of the transit time at the speed of light from a distant satellite to Earth. Einstein predicted that the speed of light as measured in a global reference frame would be reduced by the gravitational potential of the Sun as described by equation (1), which is in good agreement with experiments. Here D is the distance of closest approach. The deflection of the light beam by the gravitational potential of the Sun is very small and is not illustrated here.

If the speed of light varies with gravity then it means the equation of escape velocity is wrong.

Light travels or follows the curvature of the black hole but so curvy that it can’t escape however it doesn’t mean that the speed of light varies with gravity. I would say it never slowed down when following the curvature. 

Quote from: rabinoz on June 21, 2020, 04:14:44 PM

Quote from: Bullwinkle on June 21, 2020, 03:24:05 PM

Are you claiming that the speed of light varies with gravity?

I don't know about E E K but Einstein does "claim that the speed of light varies with gravity" with gravitational potential to be more precise.

Quote from: J D Franson

Apparent correction to the speed of light in a gravitational potential
Einstein was the first to predict that the velocity of light would be reduced by a gravitational potential [37]. According to general relativity [38, 39], the speed of light c₀ as measured in a global reference frame is given by

                                       

where c₀ is the speed of light as measured in a local freely-falling reference frame. This reduction in the speed of light can be observed if a beam of light passes near a massive object such as the Sun, as illustrated in figure 1. The transit time from a distant planet or satellite to Earth can be measured as a function of the distance, D, of closest approach to the Sun and then compared to the transit time expected at a velocity of c₀. The results from such experiments are in excellent agreement with the prediction of equation (1).


Figure 1. A measurement of the transit time at the speed of light from a distant satellite to Earth. Einstein predicted that the speed of light as measured in a global reference frame would be reduced by the gravitational potential of the Sun as described by equation (1), which is in good agreement with experiments. Here D is the distance of closest approach. The deflection of the light beam by the gravitational potential of the Sun is very small and is not illustrated here.

If the speed of light varies with gravity then it means the equation of escape velocity is wrong.

Unless the mass of the object (asteroid, moon, planet or star) has an extremely large mass the escape velocity has nothing to the speed of light.

A measure of "extremely large mass" is the radius of the object compared to the the Schwarzschild radius for that same mass.
If all the objects mass is contained within the Schwarzschild radius it collapses into a "black hole".

Schwarzschild radius
The Schwarzschild radius is given as where G is the gravitational constant, M is the object mass, and c is the speed of light.

For the Earth, that radius is only 0.9 cm so any error in neglecting the speed of light is quite negligible.

Even for our Sun, that radius is only about 3 km but the radius of the Sun is 696,340 km so any error in neglecting the speed of light is still negligible.

Light travels or follows the curvature of the black hole but so curvy that it can’t escape however it doesn’t mean that the speed of light varies with gravity. I would say it never slowed down when following the curvature.

But none of the Solar system objects are anywhere close to being "black holes" so forget the speed of light in calculating the escape velocity.

What I am trying to say is that shouldn’t the speed of light be the same relative to all observers irrespective of their frames of reference.

What I am trying to say is that shouldn’t the speed of light be the same relative to all observers irrespective of their frames of reference.

Yes, the speed of light in a vacuum is always the same to any observer.

What I am trying to say is that shouldn’t the speed of light be the same relative to all observers irrespective of their frames of reference.

Each observer in an inertial frame of reference will measure the same speed of light but the speed will not be the same when observed from another inertial frame of reference moving at a different velocity.

But why this hang-up over the speed of light in relation to escape velocity.

The escape velocity from the surface of the Earth is only about 11.2 km/s and c is about 300,000 km/s and
the escape velocity from the surface of the Sun is only about 618 km/sec still far less than c.

To get an escape velocity comparable with c you need a neutron star with escape velovities over 100,000 km/s,

So forget c when it comes to escape velocities from planets.

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

Quote

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

V_E = [2GM/R]^1/2 is the escape velocity from a point R from the centre an of an object of mass, M.

The speed of light is irrelevant when R >> Schwarzschild Radius (R_S=  2GM/c²).

The Schwarzschild Radii for the Earth = 8.7 mm (R_Earth = 6,371 km) and even for the Sun is only 3 km (R_Sun = 695,700 km).

Forget the velocity of light when talking about the Escape velocity!

Quote

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

I'm not really sure what you're asking here.

Escape velocity for an object isn't going to change no matter where you observe it or how fast any other observer is moving.

The whole business about escape velocity being higher than the speed of light is a bit of a misconception.   While that does happen at the Schwarzschild radius, the reason we can't see inside a black hole is that from our perspective, there's nothing happening inside.  Time has stopped, hence the term Event Horizon.

First check out one of the best videos on the internet:



And then some black hole basics:

Quote from: E E K on June 23, 2020, 11:01:37 AM

Quote

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

I'm not really sure what you're asking here.

Escape velocity for an object isn't going to change no matter where you observe it or how fast any other observer is moving.

Then why a pulse @ 05:50 in the video doesn’t escape the same way instead of bouncing up and down in between the two mirrors despite knowing that the velocity of pulse (300,000 km/sec) is way greater than the escape velocity as explained above.

Quote from: JJA on June 23, 2020, 04:15:01 PM

Quote from: E E K on June 23, 2020, 11:01:37 AM

Quote

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

I'm not really sure what you're asking here.

Escape velocity for an object isn't going to change no matter where you observe it or how fast any other observer is moving.

Then why a pulse @ 05:50 in the video doesn’t escape the same way instead of bouncing up and down in between the two mirrors despite knowing that the velocity of pulse (300,000 km/sec) is way greater than the escape velocity as explained above.

I watched the video and nothing in there has anything to do with escape velocity.

I'm not sure I understand why you keep linking the speed of light and escape velocity but they have nothing to do with each other.

Where would the light bouncing up and down escape to?

Quote from: E E K on June 24, 2020, 03:10:50 AM

Quote from: JJA on June 23, 2020, 04:15:01 PM

Quote from: E E K on June 23, 2020, 11:01:37 AM

Quote

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

I'm not really sure what you're asking here.

Escape velocity for an object isn't going to change no matter where you observe it or how fast any other observer is moving.

Then why a pulse @ 05:50 in the video doesn’t escape the same way instead of bouncing up and down in between the two mirrors despite knowing that the velocity of pulse (300,000 km/sec) is way greater than the escape velocity as explained above.

I watched the video and nothing in there has anything to do with escape velocity.

I'm not sure I understand why you keep linking the speed of light and escape velocity but they have nothing to do with each other.

Where would the light bouncing up and down escape to?

The velocity of a pulse (video) is greater than the escape velocity of the aforementioned jet - Right
if yes, then shouldn't a pulse also be considered as escaped - Right

Quote from: JJA on June 24, 2020, 04:43:34 AM

Quote from: E E K on June 24, 2020, 03:10:50 AM

Quote from: JJA on June 23, 2020, 04:15:01 PM

Quote from: E E K on June 23, 2020, 11:01:37 AM

Quote

But why this hang-up over the speed of light in relation to escape velocity.

Escape velocity requires for the jet on the surface of earth = [2GM/R]^0.5

This means this jet breaks the gravitational environment of earth or free from its grasp.

Let there are two observers A and B. A is at rest on the surface of the earth while B is in the inertial frame, moves with constant speed relative to A. B stands by the jet inside moving frame. What would be the escape velocity of the jet relative A and B? Will it still be  [2GM/R]^0.5 for both?

I'm not really sure what you're asking here.

Escape velocity for an object isn't going to change no matter where you observe it or how fast any other observer is moving.

Then why a pulse @ 05:50 in the video doesn’t escape the same way instead of bouncing up and down in between the two mirrors despite knowing that the velocity of pulse (300,000 km/sec) is way greater than the escape velocity as explained above.

I watched the video and nothing in there has anything to do with escape velocity.

I'm not sure I understand why you keep linking the speed of light and escape velocity but they have nothing to do with each other.

Where would the light bouncing up and down escape to?

The velocity of a pulse (video) is greater than the escape velocity of the aforementioned jet - Right
if yes, then shouldn't a pulse also be considered as escaped - Right

Escaped from what? 

Escape velocity is just a measure of how fast you have to move to get off of a large body like  a planet.  It's just the speed at which if you throw something up, it won't come back down.  That's all escape velocity is.

In a space craft there is no escape velocity. To have a measurable 'escape velocity' you have to have a large object it's trying to escape from, like a planet or a star or a black hole.

Question remains if a thing like a black hole is a celestial body. There should be one such thing at the center of our Milky Way galaxy but I haven’t seen it and I look all the time when the sky is clear. Our Milky Way galaxy is pretty big, i.e. approximately 100 000 light years in diameter, but I haven’t seen any black hole there at the center.
I have of course looked around the nearest star in our Milky Way galaxy, aside from the Sun, i.e. the star Proxima Centauri, which is about only 4.24 light years away. Experts say there is a black hole lurking there. Same experts suggest however, that it is nearly impossible to detect such a black hole aside from measuring its gravitational distortions on the light from visually nearby objects. Problem is that visually nearby objects, i.e. other stars, are many light years away. To be honest … I doubt black holes exist! http://heiwaco.tripod.com/moontravelb.htm . So their escape velocities are nothing to worry about.

Question remains if a thing like a black hole is a celestial body. There should be one such thing at the center of our Milky Way galaxy but I haven’t seen it and I look all the time when the sky is clear. Our Milky Way galaxy is pretty big, i.e. approximately 100 000 light years in diameter, but I haven’t seen any black hole there at the center.
I have of course looked around the nearest star in our Milky Way galaxy, aside from the Sun, i.e. the star Proxima Centauri, which is about only 4.24 light years away. Experts say there is a black hole lurking there. Same experts suggest however, that it is nearly impossible to detect such a black hole aside from measuring its gravitational distortions on the light from visually nearby objects. Problem is that visually nearby objects, i.e. other stars, are many light years away. To be honest … I doubt black holes exist! http://heiwaco.tripod.com/moontravelb.htm . So their escape velocities are nothing to worry about.

Yeah, you're not going to see a black hole 50,000 light years away through everything in the way with the naked eye. 

But infrared telescopes can see all the way there, and we can literally watch stars orbiting something extremely massive there. 

https://www.universetoday.com/133511/watch-stars-orbit-milky-ways-supermassive-black-hole/



How about this, a radiation jet ejected from a supermassive black hole in another galaxy.  Can't see this with the naked eye either but that's why we have telescopes.



I can't see the transistors in my phone's CPU, but they exist.

Escaped from what?

Escape from the gravity, which is almost zilch as compared to the jet with escape velocity in a similar frame on earth.

No resistance of gravity means – the frame doesn’t have control over the direction of speed of a pulse therefore it should move in the escape mode instead of bouncing up and down and get along with.   

Quote

Escaped from what?

Escape from the gravity, which is almost zilch as compared to the jet with escape velocity in a similar frame on earth.

No resistance of gravity means – the frame doesn’t have control over the direction of speed of a pulse therefore it should move in the escape mode instead of bouncing up and down and get along with.

Light travels in the direction it was emitted.  In a space craft in space there would be very little gravity.

Light bounces off mirrors regardless if there is gravity or not.

Escape velocity has nothing to do with light bouncing off a mirror.

Quote from: E E K on June 24, 2020, 10:14:25 AM

Quote

Escaped from what?

Escape from the gravity, which is almost zilch as compared to the jet with escape velocity in a similar frame on earth.

No resistance of gravity means – the frame doesn’t have control over the direction of speed of a pulse therefore it should move in the escape mode instead of bouncing up and down and get along with.

Light travels in the direction it was emitted.  In a space craft in space there would be very little gravity.

Light bounces off mirrors regardless if there is gravity or not.

Escape velocity has nothing to do with light bouncing off a mirror.

A pulse should go straight vertically up from the point from where a pulse was emitted but it doesn’t. This is what I am trying to explain.
Question: Would an apple fall if dropped from the ceiling of the said moving frame? What causes the said pulse to bounce in between the mirrors?

Quote from: JJA on June 24, 2020, 10:42:29 AM

Quote from: E E K on June 24, 2020, 10:14:25 AM

Quote

Escaped from what?

Escape from the gravity, which is almost zilch as compared to the jet with escape velocity in a similar frame on earth.

No resistance of gravity means – the frame doesn’t have control over the direction of speed of a pulse therefore it should move in the escape mode instead of bouncing up and down and get along with.

Light travels in the direction it was emitted.  In a space craft in space there would be very little gravity.

Light bounces off mirrors regardless if there is gravity or not.

Escape velocity has nothing to do with light bouncing off a mirror.

A pulse should go straight vertically up from the point from where a pulse was emitted but it doesn’t. This is what I am trying to explain.
Question: Would an apple fall if dropped from the ceiling of the said moving frame? What causes the said pulse to bounce in between the mirrors?

The mirror causes the photon to bounce back off of it.  An apple wouldn't fall from the ceiling of the space ship, but would certainly bounce off the ceiling back at you if you threw it.

Quote from: Heiwa on June 24, 2020, 09:25:58 AM

Question remains if a thing like a black hole is a celestial body. There should be one such thing at the center of our Milky Way galaxy but I haven’t seen it and I look all the time when the sky is clear. Our Milky Way galaxy is pretty big, i.e. approximately 100 000 light years in diameter, but I haven’t seen any black hole there at the center.
I have of course looked around the nearest star in our Milky Way galaxy, aside from the Sun, i.e. the star Proxima Centauri, which is about only 4.24 light years away. Experts say there is a black hole lurking there. Same experts suggest however, that it is nearly impossible to detect such a black hole aside from measuring its gravitational distortions on the light from visually nearby objects. Problem is that visually nearby objects, i.e. other stars, are many light years away. To be honest … I doubt black holes exist! http://heiwaco.tripod.com/moontravelb.htm . So their escape velocities are nothing to worry about.

Yeah, you're not going to see a black hole 50,000 light years away through everything in the way with the naked eye. 

But infrared telescopes can see all the way there, and we can literally watch stars orbiting something extremely massive there. 

https://www.universetoday.com/133511/watch-stars-orbit-milky-ways-supermassive-black-hole/



How about this, a radiation jet ejected from a supermassive black hole in another galaxy.  Can't see this with the naked eye either but that's why we have telescopes.



I can't see the transistors in my phone's CPU, but they exist.

Thanks. So some stars orbit (!) the black hole of the Milky Way center instead of being swallowed by it. Well, I don't believe it.

Quote from: E E K on June 24, 2020, 12:55:30 PM

Quote from: JJA on June 24, 2020, 10:42:29 AM

Quote from: E E K on June 24, 2020, 10:14:25 AM

Quote

Escaped from what?

Escape from the gravity, which is almost zilch as compared to the jet with escape velocity in a similar frame on earth.

No resistance of gravity means – the frame doesn’t have control over the direction of speed of a pulse therefore it should move in the escape mode instead of bouncing up and down and get along with.

Light travels in the direction it was emitted.  In a space craft in space there would be very little gravity.

Light bounces off mirrors regardless if there is gravity or not.

Escape velocity has nothing to do with light bouncing off a mirror.

A pulse should go straight vertically up from the point from where a pulse was emitted but it doesn’t. This is what I am trying to explain.
Question: Would an apple fall if dropped from the ceiling of the said moving frame? What causes the said pulse to bounce in between the mirrors?

The mirror causes the photon to bounce back off of it.  An apple wouldn't fall from the ceiling of the space ship, but would certainly bounce off the ceiling back at you if you threw it.

once a pulse is fired/emitted it actually escapes from the momentum of the frame just like a jet with escape velocity on ground escapes from the gravity on earth.

Quote from: JJA on June 24, 2020, 09:38:26 AM

Quote from: Heiwa on June 24, 2020, 09:25:58 AM

Question remains if a thing like a black hole is a celestial body. There should be one such thing at the center of our Milky Way galaxy but I haven’t seen it and I look all the time when the sky is clear. Our Milky Way galaxy is pretty big, i.e. approximately 100 000 light years in diameter, but I haven’t seen any black hole there at the center.
I have of course looked around the nearest star in our Milky Way galaxy, aside from the Sun, i.e. the star Proxima Centauri, which is about only 4.24 light years away. Experts say there is a black hole lurking there. Same experts suggest however, that it is nearly impossible to detect such a black hole aside from measuring its gravitational distortions on the light from visually nearby objects. Problem is that visually nearby objects, i.e. other stars, are many light years away. To be honest … I doubt black holes exist! http://heiwaco.tripod.com/moontravelb.htm . So their escape velocities are nothing to worry about.

Yeah, you're not going to see a black hole 50,000 light years away through everything in the way with the naked eye. 

But infrared telescopes can see all the way there, and we can literally watch stars orbiting something extremely massive there. 

https://www.universetoday.com/133511/watch-stars-orbit-milky-ways-supermassive-black-hole/



How about this, a radiation jet ejected from a supermassive black hole in another galaxy.  Can't see this with the naked eye either but that's why we have telescopes.



I can't see the transistors in my phone's CPU, but they exist.

Thanks. So some stars orbit (!) the black hole of the Milky Way center instead of being swallowed by it. Well, I don't believe it.

Yes, some stars get swallowed if they get too close, others orbit if they are far enough away.  Basic physics. 

I see stars orbiting a black hole that human ingenuity and curiosity allowed us to image and am filled with awe and wonder. 

You can feel, whatever it is you feel when you see images like that.  Pity.

Quote from: JJA on June 24, 2020, 12:57:44 PM

Quote from: E E K on June 24, 2020, 12:55:30 PM

Quote from: JJA on June 24, 2020, 10:42:29 AM

Quote from: E E K on June 24, 2020, 10:14:25 AM

Quote

Escaped from what?

Escape from the gravity, which is almost zilch as compared to the jet with escape velocity in a similar frame on earth.

No resistance of gravity means – the frame doesn’t have control over the direction of speed of a pulse therefore it should move in the escape mode instead of bouncing up and down and get along with.

Light travels in the direction it was emitted.  In a space craft in space there would be very little gravity.

Light bounces off mirrors regardless if there is gravity or not.

Escape velocity has nothing to do with light bouncing off a mirror.

A pulse should go straight vertically up from the point from where a pulse was emitted but it doesn’t. This is what I am trying to explain.
Question: Would an apple fall if dropped from the ceiling of the said moving frame? What causes the said pulse to bounce in between the mirrors?

The mirror causes the photon to bounce back off of it.  An apple wouldn't fall from the ceiling of the space ship, but would certainly bounce off the ceiling back at you if you threw it.

once a pulse is fired/emitted it actually escapes from the momentum of the frame just like a jet with escape velocity on ground escapes from the gravity on earth.

I am confused about a few things.

When you say the photon 'escapes from the momentum of the frame' what do you mean by frame?  This is on the spaceship yes?

Jets don't ever reach escape velocity, they are far too slow.  Earth's escape velocity is 25,020 mph and most jet airliners fly at 500 mph.

I think you are still confused what escape velocity actually is.  It's not simply getting off the ground, it's going so fast that you don't come back even if you turn off your engines.