Timeless black holes?

The non amateur stuff. Hawking, black holes, that sort of thing

Moderators: joe, Brian, Guy Fennimore

Post Reply
brian livesey
Posts: 5430
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Timeless black holes?

Post by brian livesey »

According to modern cosmology, Time comes to and end inside a black hole, but how can this be?
The fact that a black hole exists in the first place, impies that it exists in time. If there was no time within the black hole itself, presumably there would be no internal change either.
Everything that exists is subject to change, and change itself occurs in time: to go from one change to another presupposes a lapse of time.
When matter falls into a black hole, changes must occur to the infalling matter that then affect the status of the black hole. Without time, no processes could occur inside the black hole. In the absence of time, the black hole would be "frozen" in time, rather than active.
Or would it? :?
brian
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Re: Timeless black holes?

Post by joe »

When you say "inside a black hole" are you referring to the singularity or just within the event horizon? These are two different things. Time carries on "as normal" inside the event horizon but it is viewed differently from the perspective of someone outside looking in and someone inside looking out. At the singularity physics (and with it, time) breaks down and is not fully understood. I suppose it could be said that the singularity does not experience time but I don't even know if that makes sense.
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
brian livesey
Posts: 5430
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Re: Timeless black holes?

Post by brian livesey »

Thanks Joe. I was referring to the singularity. If processes do occur within the singularity, then, time should exist. As you imply, it's a puzzle.
brian
brian livesey
Posts: 5430
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Re: Timeless black holes?

Post by brian livesey »

What if we were to say that Time is only a mental construct, and for the ( essential ) purpose of partitioning change?
If, for example, someone waits for a train in a station cafe, do they experience time while they watch the crowd, or just a stream of change passing by? The traveller might look at his watch to check the "time", but does the dial show him anything other than fingers moving to different positions on a dial?
brian
M54
Posts: 205
Joined: Sun Apr 27, 2008 2:59 pm
Location: Cambs
Contact:

Re: Timeless black holes?

Post by M54 »

I would say the problem is we have a habit of putting zero's and infinities into anything to do with a black hole and both those cause the mathematics we have constructed around our idea of a black hole to be undefinable.

If the singularity is not actually zero size and is therefore not actually infiinitely dense it all changes.

The odd aspect of black holes is we say that the physics and therefore the mathematics break down and then we define some mathematics that we then say tells us what happens. :mrgreen:
Vick
Posts: 27
Joined: Thu Feb 17, 2005 2:24 pm
Contact:

Re: Timeless black holes?

Post by Vick »

Due to increasing gravity time slows down as you approach the event horizon and coming to a stop at the EH I wonder if there is no time within the EH and, therefore, nothing can happen.

Unless, of course, the EH is like a mirror with time within flowing backwards. Considering the idea that black holes are evaporating until their mass drops to the point where they become unstable and explode - would this be viewed from inside as the reverse of the initial formation of the black hole?
brian livesey
Posts: 5430
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Re: Timeless black holes?

Post by brian livesey »

But does time exist at all, except as an essential mental construct for monitoring change?
brian
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Re: Timeless black holes?

Post by joe »

Vick wrote:Due to increasing gravity time slows down as you approach the event horizon and coming to a stop at the EH I wonder if there is no time within the EH and, therefore, nothing can happen.
Actually, time doesn't "slow down", your clock will tick away just as normal. Maybe you mean that the clock at the EH will appear to run slower from the point of view of an observer much further away from the black hole's influence?
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
Gubbins
Posts: 5
Joined: Sun Sep 27, 2015 2:06 am
Contact:

Re: Timeless black holes?

Post by Gubbins »

I think that the main point here is that all conjecture about black holes and even the point that physics breaks down at the EH is just that - conjecture. The notion of time expressed here ignores some basic concepts. Black holes have considerable gravity such that suns orbit it at great distances indicating that the enormous mass of the black hole exists with in it. The bigger it is the greater the gravity. So the singularity (an unproven concept so far, ignoring theoretical maths) must contain the mass creating the gravity. If there was no time then there would be no energy or energy differentials and gravity would not exist from within the black hole apart from the small amount that may or may not be in a closing orbit near the EH.

As to the thoughts about time is a mental construct that makes no sense :roll: . The very particles that make up the atoms, the blood flowing in the person's body, all the breathing and chemical reactions all function through time. The very act of thinking is based on these internal time related chemical changes. Without universal time nothing would happen and nothing would ever come in to existence in the first place. Not the big bang. Not even quantum concepts. With out time there can be no energy differentials to explain energy flows such as gravity, movement (displacement) of anything from Quantum bits and bobs all the way up to light and the Universe, and chemical reactions in us and everything else that explains life and inanimate objects - think of atoms, spinning electrons, all the forces of particles and electromagnetic forces. Not even 3D space.

The question of did time exist just before the BB the answer must be Yes. (assuming the BB was real) The BB could not have commenced unless time was present to allow it. And before the BB? If the guessed at Singularity existed then it would have either not existed then suddenly did (therefore time existed already to explain the two states) and expanded or it did exist and was held by its own gravity and therefore time existed to explain the very presence of the contained energy and the forces that held it. So as you can see from my own guesswork nothing is certain but time must exist in a "singularity" in a black hole as it appears to have much greater mass than the EH shell, or if there is no such thing as a singularity then I mean the mass of the black hole.

So what do you think?
David Frydman
Posts: 5360
Joined: Mon Jan 18, 2010 9:25 am
Contact:

Re: Timeless black holes?

Post by David Frydman »

Thinking is hard work.

Not thinking is much more relaxing.

I much prefer Not thinking.

Regards, David
Post Reply