You Can Escape a black hole!! (5 Viewers)

[BIGTYMA]

you cant escape a black hole
\thread

if you want to keep on arguing post here.
https://forums.phys.unsw.edu.au/main/viewforum.php?f=14

 

[spartan31234]

Well rockets cannot escape black holes – this however cannot be explained by Newton’s concept of escape velocity. You have to understand that Newton’s escape velocity is only for projectiles. – For example taking earth – say escape velocity is 27000 km/h – u do not need to accelerate a rocket to that speed to escape the gravitational field – if you maintain a constant trust, slightly greater than the weight force – you can move away form earth as long as you maintain that trust. Escape V only applies to projectiles. By the way when I say escape I mean – move away form the field for ever.

When you apply this concept to Newton’s Definition of a black hole – it fails – more complex general relativity is required – which is not in the HSC course.

 

[spartan31234]

you cant escape a black hole
\thread

if you want to keep on arguing post here.
https://forums.phys.unsw.edu.au/main/viewforum.php?f=14

well i have been saying for a while now : rockets cannot escape black holes

 

[lionking1191]

Well rockets cannot escape black holes – this however cannot be explained by Newton’s concept of escape velocity. You have to understand that Newton’s escape velocity is only for projectiles. – For example taking earth – say escape velocity is 27000 km/h – u do not need to accelerate a rocket to that speed to escape the gravitational field – if you maintain a constant trust, slightly greater than the weight force – you can move away form earth as long as you maintain that trust. Escape V only applies to projectiles. By the way when I say escape I mean – move away form the field for ever.

When you apply this concept to Newton’s Definition of a black hole – it fails – more complex general relativity is required – which is not in the HSC course.

1. newton did not have a definition for a black hole - he was dead by then.
2. i don't see why you keep coming back to the concept of 'escape velocity' to explain something that you insist has nothing to do with 'escape velocity' in the first place. ok, escape velocity only apply to projectiles. so what? it does not address the issue of contention.

edit: could you PLEASE make clear what point you are trying to get across?

 

[spartan31234]

- i no longer agree with the title !

Black hole DEF
It follows from Newton's law of gravity that a sufficiently dense object's escape velocity will equal or even exceed the speed of light

- tats what i was talking about - but this definition is not entirely correct!

 

[lionking1191]

- i no longer agree with the title !

Black hole DEF
It follows from Newton's law of gravity that a sufficiently dense object's escape velocity will equal or even exceed the speed of light

- tats what i was talking about - but this definition is not entirely correct!

oh. goodie.

yeah well that's what the newtonian synthesis was about wasn't it, applying relativity to newton's 'classic laws of physics'?

 

[spartan31234]

do u guys rekon there should be more maths in physics ! like in the real world. We should go more in depth rather than skimming over stuff. Then again if we changed the sylabus - most teachers wouldn't be able to teach it~!

 

[sam04u]

Imagine if you will a black hole to be like a whirlpool, with an oscillating, hollow core, somewhat like a compressed version of our own. The center of a black hole would be tightly packed and also made of dispersed energy/mass.

You see there gets to a point where the mass of the core of the "black hole" would be so much that the energy could NOT move, and in turn that would destroy the energy, which can not happen. What happens then is the energy is dispersed throughout the universe (this is what some consider to be dark matter? lol I guess...)

considering most of the worlds energy exists in a) the core of the universe "burning" as it is
and b) black holes

 

[Js^-1]

Imagine if you will a black hole to be like a whirlpool, with an oscillating, hollow core, somewhat like a compressed version of our own. The center of a black hole would be tightly packed and also made of dispersed energy/mass.

You see there gets to a point where the mass of the core of the "black hole" would be so much that the energy could NOT move, and in turn that would destroy the energy, which can not happen. What happens then is the energy is dispersed throughout the universe (this is what some consider to be dark matter? lol I guess...)

considering most of the worlds energy exists in a) the core of the universe "burning" as it is
and b) black holes

...from where does that follow from? Please note I am sincerely asking, not being rude. I know very little about black holes but they are so interesting.

 

[tacogym27101990]

do u guys rekon there should be more maths in physics ! like in the real world. We should go more in depth rather than skimming over stuff. Then again if we changed the sylabus - most teacher wouldn't be able to teach it~!

yes i believe they should make mathematics a prerequisite for hsc physics and have it a calculus based course

that would be awesome

 

[spartan31234]

Ok its a lot to ask but does anyone know the deffinition of a black hole using AlbertsE's General Theory of Relativity?

- wiki
The second concept is the base of general relativity: mass deforms the structure of this spacetime. The effect of a mass on spacetime can informally be described as tilting the direction of time towards the mass. As a result, objects tend to move towards masses. This is experienced as gravity. This tilting effect becomes more pronounced as the distance to the mass becomes smaller. At some point close to the mass the tilting becomes so strong that all the possible paths an object can take lead towards the mass.[16] This implies that any object that crosses this point can no longer get further away from the mass, not even using powered flight

- it sounds like the curveature of space at the even horizon - is spherical ( or something) - hence even if a rocket accelerates - using a force greater than the weight force - it can only go in a circle and eventually into a point of singularity... i can't visualise this though!.. porb wrong though
- it is also said time stops at the event horizon..

 

[omniscience]

No, I can't. I am not fast enough.

 

[minijumbuk]

What the shit, you're forgetting mass dilation...

Also, you're only an HSC physics student. There are many things that you've yet to learn about. In other words, your 'physics knowledge' is insuffice to pose a question to the deeper levels of 'real physics'.

What makes you think that out of all the previous great scientists with an exceptional amount of knowledge, that you can coincidentally point out such an obvious mistake?

Don't rush your way to the Nobel prize, dude.


EDIT: Post is as response to the first post.

I now accept that the OP has acknowledged the flaws, and hence I'll stop further debates.

 

[spartan31234]

whats a OP?

 

[Js^-1]

Original Poster

 

[Harkaraj]

haha

 

[henry08]

We should nominate the OP for a noble prize. The OP should also appear as an 'expert' on the subejct on ACA and oday Tonight.

 

[Js^-1]

Extension Physics would be cool. They should have Dynamics in the engineering course. I'm not sure if they used to, but its in all the textbooks, well at our school anyway. I dropped Engineering after year 11 but if it had dynamics and statics, then that might have been a reason to stay. Still, physics owns Engineering.

 

[spartan31234]

- just trying to see what happens when u apply apply HSC physics to real physics - it gets owned ( sometimes )

 

[Reckonable]

Even after the event horizon

Ok I am sick of hearing, stuff can never escape a black hole -.. so the "escape velocity" is greater than the speed of light - but the escape velocity only applies to projectiles! - ie the initial min velocity to escape a gravitational field where the velocity is zero at infinity(unachievable distance)- so really u can't escape a gravitational field but that’s another storey. Say a black hole has an acceleration so great it escape velocity is ect - ^^ and would create a HUGE weight force W=Mg on say a rocket - all the rocket has to do is to counteract this weight force(+ a bit more) - and there is no such thing as a infinite weight force !!! - and if the trust is controlled the rocket can land on the hole and leave it at any speed it wants!!!! - and the rocket wont disintegrate as well - cause it is very STRONG! – Note !! I kind of contradicted by self ..– cause by definition of escaping a black hole gravitational field is impossible as gravity is zero at infinity (unachievable distance!) - but using that…..definition of escape – moving away.. I know that it is possible to escape a black hole – IF U ACCELERATE !!!!!!!!!!!!!!! \\

- and don't give me - " a black hole has infinite mass" - cause then the gravitational feild on any mass will be infinte and the whole universe will get sucked in!!

By the way when u fall towards the earth the earth falls towards u! - Equal and opp forces - Gravity and resulant // also have to understand what is an internal and external force as well

i want what hes on