Exactly. Some games are perfect for touchscreen, like Temple Run, Candy Crush and Subway Surfer. I don't think that's the real problem with mobile gaming.
>>Outside the horizon, an object can escape the black hole’s gravitational pull if it’s moving sufficiently fast; inside, it would need to move faster than light-speed, something forbidden by the laws of nature.
Are they trying to say that if there was something that could move faster than light then it can escape? If that's is forbidden by laws of nature, then how did they determined that this is possible?
All things have a constant speed in spacetime: the speed of light. If you stand completely still, you travel through time at "the speed of light". If you start moving faster in space, you'll lose a similar amount of speed in time. Go fast enough, and your life will pass in slow-motion. Go at the speed of light and your time stops. Go faster than the speed of light, and your time will start going backwards.
Since you can't get out of a black hole normally, the only way to get out is by reversing time. I.e., going faster than light might be an option to get out of a black hole.
Of course, doing so is nonsense, but the maths work out.
The constant speed is actually the speed of a massless object through spacetime. It just so happens to be that photons have no mass. Also, going at high speed wouldn't make your life pass in slow motion to you. It would simply look that way to an observer who was moving vastly slower than you. The dilation in time is as a result of difference in relative velocities, rather than the speed of time changing.
This is also why the part about "go faster than the speed of light" doesn't make sense in physics. Motion is a four dimensional vector, with three points giving a point position, and the forth giving velocity through spacetime. Thus you wouldn't be travelling through "time" backwards, but through spacetime backwards.
Hope that helps. For more information, you may want to read up on the geometry of Minkowski spacetime.
In a reply I also just made alongside yours, I mention that we're actually measuring the speed of causality - so you could think of "the speed of a massless object through spacetime" as the "speed of causality".
To be pernickety (because we like that around here), what I think you're referring to is the transmission of information, which is still down to the maximum velocity at which something of no mass can propagate through spacetime to interact with something else within its light cone[0][1].
The important thing in causality is the concept of the light cone. For things that happen far apart enough that the light cones don't interfere with each other, causality doesn't matter. One could happen first, or the other. It's only when you consider two things where the interaction occurs that the propagation matters.
Clearing this up a little further, having just read your other comment, the causal link between events and the speed by which information propagates is as a result of c, not the cause of it.
There isn't really such a thing as faster than light. It's more that light travels at c, than that c is the speed of light. By way of analogy, it'd be like having a chart with an x and y axis, and having a line going straight up the y axis, then asking "but how can we make it more along the y axis?". I realise in terms of numbers it makes sense, but in terms of physics it doesn't. There's no such thing as faster than light through spacetime.
Travelling at c, your perception of time would have stopped. From that point, it can't become more stopped, any more than you can go faster.
It's an equation with one unknown. Even if it can't be "done", maths can calculate it. It will just give you the absurd result you'd expect that you need faster-than-light velocity.
Sadly, there isn't a quick answer to this. The shortest version I can think of is that there's a fixed limit on how fast something can travel. However, gravity is a distortion of space and time, and the more gravity you have, the faster you have to go to leave what you're starting from. Think of it like running on a treadmill - the faster the treadmill goes, the faster you have to run if you want to run off the end of it. At a certain point, the treadmill goes faster than you can run, and you cannot run off the end.
Past a certain point, the distortion of spacetime becomes so great that no speed attainable can overcome the effect of it dragging back. So even travelling at the speed of light, you couldn't go faster than the gravity treadmill speed pulling you back in.
For clarification - gravity is nothing like a treadmill. It just happens to work nicely as an analogy for this.
Minkowski geometry preserves causality, that is all observers agree on the order of events, not necessarily on the time between events. So every observer sees me catching the ball after he sees me throwing it into the air. If I would move faster than light speed towards an observer, then he would first see me catching the ball and then throwing the ball. ( Since I traveled faster than the signal that the ball was thrown.)
So these claims, you could escape a black hole if you travel faster than light speed, should be read as, if we use our Euclidean sensibilities in a Minkowski setting,... It is in some technical sense correct, but without the technical details meaningless.
It's not that they know it's possible, they know nothing is forbidding it. If you could move faster than light you could escape. What's forbidden is moving faster than light, not escaping.
mmm its not theoretically permitted to CROSS the light speed threshold, however, going faster than light is common, as neutrinos do, moving backwards in time.
It's opposite for me. I have hard time sleeping at someone else's house. I have to lay down for hours before I get to sleep. I get best sleep in my own room.
In response to both parents of this comment, my first reaction would be that "of course" it's personal: maybe your bed at home is not that great, or a neighbouring mine makes sounds that don't register consciously anymore but still keep you up. But then again, in my experience it is a personal thing beyond a person's environment. I know people of both kinds and the location does not seem to matter.
It's often the case in non-exact science studies that the results are difficult to reproduce. Besides the obvious "they're not called exact", it's interesting. What is this caused by? Would, in this example, some people lack the 'feature' of sleeping with half a brain?
