GLaDOS 
And it is no doubt followed by the word ‘modality’.
Really? Because everything I’ve ever seen or read lists space-time as being at the top of the list of reasons for why there has never been a successful grand unified field theory. I guess I must have heard wrong.
Technically, a grand unified theory has nothing to do with space-time; it’s a unification of the ‘microscopic’ forces, i.e. electromagnetism and the weak and strong forces, alone, without gravity. Incorporating gravity so you get a unified description of all the known forces is often called a ‘theory of everything’, though I’m not too fond of that name. But this is just a terminological quibble.
Content-wise, you’re right, basically – the way space and time are treated in quantum theory and relativity are indeed different, which is a source of difficulty. Roughly, space and time are taken as absolute, static background parameters in quantum theory, while they themselves are the dynamic quantity of general relativity. It’s a more serious problem with respect to time. This is a reason why one often prefers the ADM formulation of GR in quantum gravity research.
But this doesn’t mean that in a different approach to gravity, there would be ‘no such thing as space-time’; these problems are not due to some choice of Einstein, and are also present in other approaches, though they may assume a different guise there. (Though I should mention for completeness that there is indeed a theory that breaks, in a sense, the symmetry between space and time, and which may be successfully quantized – however, this theory (known as Horava gravity) has problems of its own, in particular, it’s not clear if it is actually phenomenologically adequate.)
Here’s an article you might find interesting, but given your response, I’d like you to then explain the author’s error in the following quote - emphasized passage in particular.
Huh? What error?
OK. Let me back up. You see no conflict between Leibniz-Machian relationism and the concept of spacetime?
I think that if you want to have a philosophical debate, you should head over to GD… (And for the record, the notion of space-time in GR is not a substantivalist one, as demonstrated by the famous hole argument – only wordline coincidences (actual meetings of, for instance, particles) have physical meaning, not the background space-time in itself. This is not a priori in conflict with relationalism, though one can discuss certain finer points.)
I believe the article I cited proves otherwise, but perhaps this article spells it out more clearly.
edit: There’s also this one for Scientific American subscribers.
All of these arguments ignore one big fact-there is no “Past”. The past does not exist-it ceases to exist as time advances. This is proven by chemical reactions, increase of entropy, and conservation of energy. You cannot “enter” the past because it does not exist. There is only the present. All the while you are entering your “wormhole”, time is advancing, as the present displaces the past. Whatever frame of refernece you are using as a “baseline”, time is advancing in it, and there is no way that the past state of this reference point can be entered.
My understanding is that the Würm generator from Ikea draws a LOT of power. SenorBeef’s neighbor should be able to give you tips on how to keep your electric bill down.
You might be in luck then:
That’s pretty interesting. However, on first glance it appears that those aren’t “real” monopoles. It is possible in some systems to have a structure that looks a lot like a monopole, but isn’t one in the traditional sense. They’re basically equivalent to a very long and thin bar magnet–as long as you’re close to one end and far from the other, it looks very much like a monopole.
I don’t know enough to say that’s exactly what’s going on in that paper, but I suspect it’s something close: that there’s some quantum mechanical effect that ends up looking like a monopole current, but doesn’t really reflect the underlying physics. There’s a lot of QM that works this way; for instance, vibrations in a crystal lattice can be modeled as a particle called a phonon. The thing is, there’s no actual phonon; it’s all just vibrations in the end. But it behaves as if there were one.