Um...One big problem with the article I see...

"The black Saturn can only exist in a space with four dimensions, rather than the three we inhabit."

We only live in 3 dimensions? So where did time go?

We live in 4 dimensions, not 3. So the basis for the article is a bit off. If they mean 4 vs 5, then ok, I'm curious. I'm also curious as to how an extra dimension (which I've never denied may exist) proves/disproves string theory.

I guess I'm used to playing devil's advocate on this one...except everyone in the field seems to be in favor of string theory, so I come out against it.

Speaking of said theory, one of the major players in the field has been hosting a show on the Science Channel - 2057. He's a chair of the physics department at City College in NYC, Michio Kaku. The show is very very good, and he's a spectacular personality.

Yeah, I noticed that too (hence my rather carefully worded "more than its perceived"). Personally, I'm thinking it's more likely to be a poorly worded press release or a goof by the author that somehow got past the editor. Of a science publication no less.

String theory predicts extra dimensions, which haven't been found. If they find even one extra, it's, in my mind at least, equivalent to solving for N. They still need to solve for N+1 to tie it up, but it would definitely seem to represent a first step. It would also flatly disprove string theory if no extra dimensions were found at all.

Unfortunately we don't get the science channel on our basic cable subscription :(.

No science channel?! Horrors!

I don't know how you live without it. That and Discovery are my favorites.

Well, and Sci-Fi. Though I could do without the awful movies (Now, from the mind of William Shatner, "Fire Serpent" - Actual quote heard yesterday on Sci-Fi).

I thought that 2057 show could also be seen on Discovery, TLC, or the Hitler (History) Channel. I don't believe we've got the Science channel (though we do have the SciFi network) and I know we've seen it.

If nothing more, it's an amusing view of what won't happen. Hell, I don't think there's a single future show like that which has ever been correct or even close to correct.

Hm. Maybe it is on the others, I've only seen it on Science.

I actually like it because it shows current tech and where the world might go with it.

But yeah, I have a whole lot of fun getting all worked up over how stupid the concepts of their future are. Some of the stuff is just downright ridiculous.

I still wonder about time being a dimension. If it was, would it not theoretically be possible to move in the opposite direction that everything else is moving, instead of just slowing down along that dimension?

The pressure equations for water can be compared to the voltage equations for electricity, but that doesn't necessarily mean water is a kind of electricity.

Quite correct T, and trying to figure out exactly why we can't move forward and back in time at will is still (as I understand it anyway) a great big question mark in theoretical physics. It's the whole "arrow of time" thing.

Again, as I understand it, general relativity does in fact allow time travel, and it's actually not all that complicated. One simply needs to create a mass 10-15 times greater than the sun and spin it up to ~ 60-70% of the speed of light. Easy!

I watched one of Discovery's shows on the future of the car. I think it was one of the 2057 series, and I while it was amusing to watch, the results were less than what I thought they should be. Everything appeared to be somewhat evolutionary, not revolutionary. While it was focused on personal transportation, the basic concept of a personal craft for each person or small group was still a given. So was contact with the ground, the assumption of a commute to work, personal auto ownership, etc.

Hmm... maybe that's what the "end times" business was about in that Book of Revelation. The Nemesis star intrudes upon our solar system, and time reverses as a result... dead rising from the grave and such.

Though, personally, I consider time a dimension only as far as it's mathematically convenient to treat it as a dimension, such as when calculating changes over it. I can create an n-dimensional array in my computer, but that doesn't mean it actually has n-dimensional components, just that I can store data and make calculations as if it did.

Tatter, are you referring to the Asimov book? I just came across my copy while cleaning up the mess the cats made of the bookcase, so it's in the forefront of my mind.

Time is a fourth dimension, and quantum particles do move in different directions in time, but when it comes to macroscopic objects, relativity comes into play (the whole mass/energy set of equations).

My big question, one I've been dealing with for a while, and one I'd really like to end up studying as a possible masters or PhD topic is the concept of entropy in a 4D "field" where there is no mathematical concept of forwards/backwards, and the effect of gravity on such a field.

Tatter, I can see how you consider time to be a purely mathematical dimension, and I think I might agree, under certain circumstances, but hasn't Hawking pretty much completely proven that it's an inextricable part of the fabric of space that we exist in?

Now back to my current attempt to prove my teacher wrong that gravity is a force (it's a field, damnit...forces are variable, fields are constant).

But isn't the force of gravity proportional to the masses and inversely proportional to the distance? Doesn't that imply it's variable? Or are you saying that with a set of constant variables (2 2-2kiloton objects 500 meters apart), the force of gravity will never vary. if you introduce a new object or change the distance, the force will move to a new constant value. Given that, it's a field?

Granted, at this point I'm fairly liquored up on Makers Mark (yay bourbon), but I think I can still answer this...

Yes, while fields (like electromagnetic fields) are variable over distance, within the constraints of a specific set of variables, a field will have the same results (the example I think of is that at sea level on Earth, gravity will always have an acceleration of 9.8 m/s^2 no matter what the mass of the object falling). A force is always a variable, dependent on what is causing the force.

A better way of saying it is that forces cause, while fields are. Make sense?

I thought the difference was that forces are one-dimensional vectors, while fields are two-dimensional areas or three-dimensional volumes that exert forces on matter or energy that passes through them.