Posts Tagged‘black hole’

Information Might Not be Lost to Black Holes, Hawking Posits.

Black holes are a never ending source of scientific intrigue. They form when a star of appropriate mass, approximately 5 to 10 times the mass of our own star, reaches the end of its life and begins to fuse heavier and heavier elements. At this stage the outward pressure exerted by those fusion reactions cannot overcome the gravity from its mass and it slowly begins to collapse inwards. Eventually, in a calamitous event known as a supernova, it shrinks down to a point mass of infinite density and nothing, not even light, can escape its gravitational bounds. Properties like that mean black holes do very strange things, most of which aren’t explained adequately by current models of our universe. One such thing is called the Information Paradox which has perplexed scientists for as long as the idea as black holes has been around.

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The paradox stems from the interaction between general relativity (Einstein’s description of gravity as a property of spacetime) and quantum mechanics (the processes that affect atoms, photons and other particles). Their interaction suggests that physical information about anything that crosses the black hole’s event horizon could be destroyed. The problem with this is that it violates the generally held idea that if we have information about a system in one point in time we should be able to determine its state at any point in time. Put simply it means that, when you’re looking at a black hole, if something falls into it you have no way of determining when that happened because the information is destroyed.

However renown physicist Stephen Hawking, whose work on black holes is so notable that one feature of them (Hawking Radiation) is named after him, has theorized that the information might not be lost at all. Instead of the information being lost or stored within the black hole itself Hawking states that the information is stored as a super-translation (or a hologram, a 2D representation of 3D data) in the event horizon. Whilst for all practical purposes this means that the information is lost, I.E. you likely wouldn’t be able to reconstruct the system state prior to the particles crossing the event horizon, it would solve the paradox.

The idea might not be as radical as you first think as other researchers in the area, like Gerard t’Hooft (who was present at the conference where Hawking presented this idea), have been exploring similar ideas in the same vein. There’s definitely a lot of research to be done in this area, mostly to see whether or not the idea can be supported by current models or whether it warrants fundamental changes. If the idea holds up to further scrutiny then it’ll solve one of the most perplexing properties of black holes but there are still many more that await.

Interstellar Brings Hard SciFi Mainstream.

As I hope is blatantly obvious by now I’m very much a fan of the sci-fi genre. It started out as a fascination with the future, with all the tech wizardry that it promises us, however it’s long since grown into a full fascination with the world of science and what plausible futures could arise from it. Thus, whilst I enjoy a good story in its own right, sci-fi movies and other media are a great opportunity to explore scientific principles and I love to see how they’re used as plot devices. Of course the narrative will often take precedence over the laws of the universe and whilst I can appreciate a departure for the sake of plot I have my limits, like Gravity’s take on how orbital mechanics work. However there’s been quite the hubbub around the science behind Interstellar and I finally managed to catch it over the weekend.

interstellar.black_.hole_In terms of basic science Interstellar gets top marks for getting so many things right. Things like travel time between planets in the solar system, gravitational lensing of light around objects that have heavy gravity or spacetime warping properties and the handling of relativity all line up with my (admittedly limited but I’d hazard a guess better than average) understanding of how those principles work. The black hole itself was absolutely stunning with the interaction of the accretion disc with the strong gravitational lensing, something which now seems so obvious, giving us a new perspective on what these monsters would actually look like out in space.

The robots are also one of my favourite aspects of Interstellar as they go from being what appears to be some kind of clunky, cumbersome relic of the pre-blight era they’re in fact highly capable machines. The designs are incredibly interesting too as whilst many movies would’ve gone for the stereotypical humanoid Interstellar instead opts for a HAL-9000esque monolith. It’s hard to discount that their personalities play a big part in this too, especially with all the humour around their programmable emotional settings.

PLOT SPOILERS BELOW

There are numerous liberties taken with certain mechanics however, all which are somewhat forgivable since they’re in aid of the plot. The small craft which are quite capable of achieving orbital velocities would have to have some kind of advanced engine that doesn’t rely on propellant and has the required thrust and specific impulse to achieve such feats. This is somewhat hinted at the start when the craft they use to get to Saturn makes it there in 2 years (I’d assume without any gravitational assists) however it’s still something that bears mentioning. It’s mostly only because if they had technology like that then it’d be quite easy to get a lot of people into space, potentially making that habitat they were working on viable without needing the secret “gravity” source.

As with all movies that like to play around with the notion of time things start to get a little hand-wavy once you start mucking with the timelines. Once Cooper’s character is stuck in the tesseract he’s essentially creating a paradox since he wouldn’t be there without the manipulations he caused, yet he is already aware of them when he’s making them. The one way to rationalize this away is to eliminate the prospect of free will within that world and so Cooper was compelled to do that no matter what happened. Otherwise he could, say, send the quantum data to someone else through another method, rendering the whole mission moot (but then introducing yet another) paradox to contend with. Indeed whilst this later part of the movie is a great piece of cinema it’s riddled with scientific problems, one that likely needs a novel to explain them away.

One thing that does irritate me about films of this nature is that they usually follow the format of “everythings going ok for a bit until things go all Event Horizon on you”.  I get that this is playing into the fragility of the human condition, where our survival instinct makes us do things we otherwise wouldn’t, however it does feel like the trope has been done to death. There’s multitudes of other avenues to pursue to provide that kind of tension without relying on humans going postal, but it seems human fallibility is still the route of choice. Then again hard sci-fi is a hard sell without a relatable human element, which I guess is the reason we keep seeing it.

PLOT SPOILERS OVER

All in all I thoroughly enjoyed Interstellar despite the last sections wandering into extreme hand-waving territory. The scientific basis which it begins from flows through the entire movie, providing a great backdrop for the rest of the movie to build on. I’m looking forward to seeing a breakdown of how all of the strictly-not-scientific elements were developed as there’s a lot of questions I’d like to see answers to. In the same vein though I’m also completely ok not knowing as the discussion my wife and I had afterwards were just as interesting as watching the movie itself. Definitely a must see for all sci-fi fans out there.