Forecast: Scattered high clouds, no rain.

Phoenix Mars Lander

What about temperature?

I told Nasa the Sky was grey. But did they listen? Perhaps they will respect the wisdom of the Star Empire now.

You would think that the amount of money being used to build these crafts; they could afford a high resolution color camera? They are probably transmitting data back to earth on WWII radios also….


[This image is brought to you by US tax dollars]

Not that relevant with the thread but I just read that scientists exposed some poor little animals called water bears to the open and harsh vacuum of space and some of the little bustards survived!

http://news.yahoo.com/s/space/20080908/ ... kedinspace

I'll only say this... Tin-Man?

I don't think it is genetic engineering. Im signed up to a weekly science email and they had a link to their own article about this in there. I also read articles by them a few months ago about bacteria and other creatures that have been blasted with radiation and all sorts of things and they've survived. Life is just tougher than we thought.

@3of12: As accurate as the statement is, those 15 minutes are a light-speed time delay. IE Mars is 15 light-minutes away... sometimes. It ranges from... um... I forget, exactly. I think it's ~10 to ~30 lightminutes depending on where we are relative to each other in our orbits. I'd have to do the math to know the timing for sure... Still, the point is (and you probably know this already, and I apologize for being so nerdy ) that the bandwidth between here and Mars is not equivalent to transfer rate. Phoenix actually has a pretty good bandwidth, all considering. However, the receiving antennae have a very limited per-project bandwidth.

@Valcoren: Actually, they *do* have a high-res color camera. But because of the before-mentioned bandwidth limit, sometimes a low-res camera can send pix you couldn't afford to send (bandwidth wise) if it were high-res.

@captain_picard: There have been several incidence in Russian cosmonautics where *humans* have been exposed to a vacuum, either in part or as a whole.
In one instance, a cosmonaut deliberately pulled off his glove so he could manipulate an object with his bare hands. NOT a recommended maneuver. However, because of an ingenious suit design, only his hand was exposed to vacuum and he was fine.
In the one instance (I know of) that a person, as a whole, were exposed to vacuum, they died of asphyxiation, not explosive decompression.
~~~
It's good to see y'all are still chugging along.

Hey ZDarby, nice to see our resident physicist is around again!

Of course we're still here. The forums are protected from evilness by my Tal'Shiar agents. But you'll never even know they are there...

Hey ZDarby, you're a physist as well? Me too!

This is the start of an invasion to this forum by physists!!!

Make it so.

No. Not an actual physicist... An armchair scientist. Which is to basically say, someone who can explain the idea but can't calculate it.

On this forum, I'm basically a gad fly.
No take over is eminent.
Sorry Capt.

Nice try ZDarby. You can't fool the Tal'Shiar. We have contingency plans against physicists. We have...the chemists!

A chemist is just a physicist who prefers Schrödinger to Dirac... Poor deluded fools.

That's what I'm trying to explain to people but they don't seem to get it. There's no chemistry guys, it's just physics!!!

sorry to disillusion you guys here but it's all just mathematics! (modulo real-life relations )

OK, so if you guys are all so smart how does that relativity, time slows down when you go fast, thing play out with a Star Trek warp drive? Does the warp of space-time make it all good again or do we get to the Acarmarian star system ten years after our sun has gone pop fizzle?

First, there is a direct one to one relationship between Dirac and Schrödinger. As Malvoisin says: modulo real-life relations. Another way of saying it is: It's all science. Fermi would say, "There are two kinds of science: Physics and stamp collecting." He has an interesting point. IE, you can explain or categorize; and sooner or later, someone will find an explanation for the categories. That's what happened to chemistry. But the arrogance of physicists is both erroneous and ill advised. There's simply too much knowledge for any one discipline to encompass, even by name. And though it's fun to feel superior, it's ultimately self-defeating.

Warp mechanics is, of course, an unknown. Anything said on the matter is speculation, obviously... However, if you assume, as many do, that at its core it's bending relativistic spacetime, than one can explain away relativistic effects with special curvatures...

Let us make a mental model. Let us represent the curving of four dimensional spacetime in three dimensions with an elastic sheet. The bending of that sheet up or down represents the relative experience of time and the sheet itself are coordinates in space. (This is a pretty standard, though often misunderstood and abused, model.)

Place upon the sheet your ship. It makes a slight dimple on the sheet directly below it which represents the difference in spacetime experienced by the ship compared to its surroundings. This difference is created by both it's mass and its momentum. If either goes up, the dimple gets more pronounced. This, you already know. Still, let's go through the motions. Imagine the ship uses thrusters. As it travels faster, its momentum increases and the dimple gets deeper. The effect is exponential, so the effect isn't noticed at first. Only until about half the speed of light does the dimple's depth become noticeably bigger. As it does so, you'll notice the actual area within the dimple gets larger, even though its circumference really doesn't, that much. This is where spacetime dilation really comes from: Light within this dimple has to travel longer within the dimple to get the same "distance" as before. So, where as before the acceleration, light would have taken only a second to get from the from of the ship to the back of the ship, after the acceleration it might take a handful of seconds to do so along the new curvature of the dimple. Einstein's brilliance was to say, "Well, since all our experience of time is measured via the speed of light --which controls all forms of electrical and magnetic forces-- time actually *is* going more slowly for those inside the dimple. What's more, measurements of space are *also* light-based, so our experience of *space* is contracted, too... Weird."

Back to warp fields. Place the ship back on the sheet at rest. Now, imagine the ship is enveloped by two force fields. The first keeps the spacetime directly around and within the ship from bending much. The second field does two things at once, contracts the spacetime (making a dimple) in front of the ship and expands it (making a hill) behind. It would look like the vessel were riding a wave, a gravity wave. In effect, it would be: The expansion behind would want to fill the compression in front. And the ship, caught between the two, would get pushed forward. However, notice the first field, that protects the spacetime of the ship from warping, is keeping any odd, relativistic effects from happening within the ship? No effective relativity means no time or space dilation.

Under most conditions, spacetime can only move at the speed of light. So, as it is, the ship would travel exactly at c. As it turns out, spacetime may move faster than light under the right conditions. (I don't know, exactly, what those condition are but I know they're experienced by the universe at the Hubble Radius.) It seems perfectly possible to expand this model into one that would allow multiples the speed of light.

It's all, of course, speculation piled upon speculation. My preference is not this model, in fact, but one of additional, fractional spacetimes being added to our own, so that the vessel would exist within a larger, fractional spacetime greater than 4 but less than 11. This is a far more difficult model to explain, so I wont try.

Time dilation when you go fast (assume constant speed) is a special relativistic effect and is totally different from warp drive theory. Putting Star Trek aside, ie in real physics, any attempt at creating/explaining warp drive should use general relativity. Actually, there is such a model that can immitate warp drive and goes under the name Alcubierre drive (see http://en.wikipedia.org/wiki/Alcubierre_drive) after the guy who figured out the model.

To cut a long story short and spare you the gory details, the main point of Alcubierre drive is that instead of having to go at great (but subluminal) speeds in order to cover large distances you can curve spacetime so that distances in front of you are smaller than normal and distances behind you are larger than normal. So, even by travelling at low speeds (and therefore no time dilation) you can cover great distances (ie you make a light year appear as km!)

Some more explanation/details are now in order:
1) You travel at low speeds only in your coordinate system. Think of it like this: even when you're inside a car travelling at 150km/h with respect to the ground/a house etc, you're standing still with respect your car (your coordinate system)

2) Unfortunately, you need exotic matter in order to create the Alcubierre drive. In particular it should be like Dark Energy, which causes the universe to accelerate but that's obviously a bit difficult to come by...

3) It takes a lot of energy to curve space time. Some simple/handwaving calculations reveal that it takes about the energy equivelent of Jupiter (through E=mc^2) even for a small trip!

Conclusion: No warp drive in the near future!

Then again you never know what the future holds...

PS Sorry for the lecture, but you asked for it

You mean gravity waves. Actually spacetime doesn't really move, but vibrates. just like a wave.

The reason that you can go faster than light is that you can curve spacetime as much as you want (forget the energy demand for a while) and that would look like Faster Than Light (FTL) travel to an outside observer.

I agree, of course it's speculation! The other model you mean is I think subspace. Think of it like spacetime has layers, and that in every layer distances between two fixed points becomes smaller and smaller as you deeper in the layers

I vote to rename this the science thread!

I'd always imagined Warp to work in the you say ZDarby, although I wouldn't have thought to describe it as a "wave". That's a very concise way of thinking about it. I'm not a physicist in any way though (I failed AS Physics - but then so did everyone else in my class coz we had a rubbish teacher who spent most of the time playing Doom on his computer), so whilst I was able to imagine it, I wouldn't have been able to explain it.

As for the other dimensions theory, I believe that may also have some part to play based on my limited grasp of the subject. Warp speeds are often described as being "deeper" levels of Subspace, and a place where the laws of physics are sufficiently different to that of the third dimension as to allow for FTL travel, without being sufficiently different to allow the passage of of people and objects through without causing that object to...well cease to exist or undergo some unknown change as required by those unknown new laws of physics. As FTL travel is theoretically impossible in the third dimension, the only logical answer as I see it is that Subspace is indeed akin to another dimension, or is at least part of the way towards being another dimension.

Travel within Subspace itself is also relatively easy; it is entering it and each successive layer that is difficult due to an exponential increase (At the layer boundary level) in power requirements. Once you have broken through into the next layer, you don't need to maintain the same power level to continue at increasing speeds up until the next layer of Subspace. This only adds further weight to my mind that Subspace is indeed at least partly another dimension for otherwise it would be a relatively easy place to get to.

I knowI'm not very good at writing sciency stuff, and pictures are worth a thousand words, so here's a picture to explain the above to those that I have lost with this post. Hopefully it will make more sense than my ramblings.

@Capt_Picard: Correction accepted: Gravity waves propagate at C. You'll notice the above explanation is basically a shaped/controlled gravity wave?

Agreed: One only *looks* like one's traveling FTL, from an external perspective, no matter the model. Still, the question remains, which model do you prefer and how do you wish to explain away the lack of relativistic effects? I chose to invent a model rather than find someone elses. I chose this 'cause I could control how involved an explanation I would need.

There are, of course may models. I've always liked the Alcubierre drive but I couldn't think of a way to explain it at that moment. You did quite well, I may add.

No. Subspace is not what I meant.... But, I have to be at work soon and do not have anymore time.

@anyoneelse: I'm not ignoring you. I just don't have time right now...

I prefer the one that might in the long run actually work! The lack of relativistic effects is easily and naturally explained. Actually, you said the answer yourself: "One only *looks* like one's traveling FTL, from an external perspective". In all FTL models (warp drive Alcubierre and subspace alike & wormholes) the traveler is only travelling at small speeds with respect to his coordinate frame, hence no (special) relativistic effects.

This model is definately a variant of subspace theory (in the Star Trek mythos) or extra dimensions in physics. If by fractional you just mean "extra", then it's just about gravity in extra dimensions (a concept as old as General Relativity). However, if by fractional you mean something like 5 and 1/2 dimensions then the nearest I can think of is fermionic extra dimensions in Supersymmetry (it's close but not exactly this).

It's not arrogance for 2 reasons:
1) I didn't create physics, so I can't take credit for it, therefore I can't become arrogant even if I wanted (At least that's how I see it)
2) Chemistry explains (better just tries to describe) the interactions between molecules. Give me Schroedinger's equation (which is physics) and I can do the same! Actually that's what chemists do...

Anyway, even though I'm not a Quantum theory aficionado, I hate it when chemists use the term Quantum Chemistry instead of Quantum Mechanics

PS I had a fight about this (Chemistry vs Physics) with a friend a long time ago... How the f@©k should I know that her parents where both Chemistry professors at the University? After that she wouldn't speak to me for more than 6 months

see, ultimately, that's why (the) "chemistry" is arguably equally important . Btw. a mathematician would have just said that chemistry is a proper subset of physics so the cardinality is smaller (assume knowledge is finite) therefore physics is more powerful, discussion end. okay, I guess her reaction would not have necessarily been different then .