Wakes and Pressure waves in Space

I was watching the opening credits of Star Trek Voyeger the other day and noticed something peculliar, when the ship flies through a gasious cloud formation it creates a pressure wave and a wake. I would not think that this would be the case in the vacuum of space. I understand that the
gasious cloud would be displaced be the presence of a large solid object travelling through it, but would it swirl back around the ship like cigarette smoke when you pass your finger through it or would it simply remain seperated? Futhermore, the Pressure wave is represented by a clear
space around the hull of the ship thus making it look as though there is some unseen force between the ship and the gasious cloud, this could be simply written off as the “shields” of the ship being up in this sequence.

So, ultimately do craft is space create wakes and pressure waves? And, if you were to take the Space Shuttle through a gasious cloud would it create a wake represented by gasses swirling back into it’s path?

Thanks(sorry for the wordy question)

those special effects are totally bogus. they simulate air displacement, and the swirling, current effects you see there. Gaseous clouds aren’t dense enough to see close up like that either. And the spaceship doesn’t have enough mass to induce gravity waves to displace local matter significantly, either. Also note: Things don’t blow up with a bang in outer space, either.

I understand that the effects are mostly “Bogus” but in the same breathe it does raise the question. As for gas clouds in space we are talking hypothetically and because we have never seen one does not mean they do not exist.

Gas doesn’t lend itself to that sort of density in hard vacuum. I remember the opening sequence fairly clearly (and that’s about as far as I ever make it into Voyager–it sucks pretty hard). If you were to take the equivalent amount of gas, it would just disperse into a much thinner cloud the size of a planet, as far I remember from high school chemistry.

Dunno if the same logic holds for “space dust,” but then again, if the Voyager craft were to ram into a cloud of particles that dense at relativistic speeds, it would have more problems to deal with than finding out whether or not it left a wake… :slight_smile:

Doh. Make that physics class, not chemistry. Taught by the same, incredibly dry teacher…

Special effects like nebulae are often created by dye in water. This one may have been made that way, so that’s probably why the cloud swirls that way. It looks cool, even if it is screwy from a scientific standpoint.

[trekgeek] The clear area in front of the ship is more likely due to the main deflector, not the shields. Starships have deflectors to push aside all the dust and micrometeoroids that float in otherwise empty space. Unlike the shields, the deflector is in operation whenever the ship is moving.[trekgeek]

You can make feeble waves even in very thin gases. And at the altitude the space shuttle orbits there are still wisps of atmosphere. Even in deep space there is some matter present.

The problem is that not enough energy gets transferred to the gases to make a detectable wake. And this is a good thing because any energy that does get transferred is no longer available to keep the shuttle (for example) in orbit. That’s why satellites in low earth orbit (LEO) come down eventually. The incredibly thin gases up there finally slow them down enough that they drop into the thicker atmosphere and burn up.

Physically, the gas molecules are spaced so far apart that they have essentially no interaction. The space shuttle, flying through this thin gas, hits some gas molelcules and changes their trajectory. But the molecules are so thinly spread that they are unlikely to hit another gas molecule. It’s like trying to do “the wave” when you’re the only one in the stadium.

It takes enormous forces to maintain pressure waves in space. Solar flares do something similar but most of the energy transferred is electomagnetic rather than through gas kinetics. There are waves of pressure that pass through the galaxy that trigger star formation but these are created and maintained by galactic size forces, not passing spacecraft.

If Voyager (or the space shuttle) were to pass through a cloud of gas dense enough to cause a visible wake it would behave like it always does when it passes through gas: it would get hot and slow down. When the space shuttle does that we call it “re-entry”. Of course Voyager has shields and monitors that guide it through these difficultes. (Tuvok: “Hull integrity is down to 19%, Captain. At this rate we can remain here for only 13 more minutes!” Janeway: “Take us to warp 9, Mr. Paris!”)

A nebula is not as dense as is shown in the opening credits of Voyager. What appears to be a thick cloud as viewed from Earth would still look like a vacuum if you were actually sitting in the middle of it.

Cool graphic though.