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planethollywood
2003-Jul-02, 05:02 AM
What would the effect on time and the individual be, if one could bring themselves to a dead stop in space?

Musashi
2003-Jul-02, 05:11 AM
Check here (http://www.badastronomy.com/phpBB/viewtopic.php?t=6379)

Peter B
2003-Jul-02, 05:58 AM
What would the effect on time and the individual be, if one could bring themselves to a dead stop in space?

Dead stop with regard to what?

There's no universal reference frame in the universe. This means that if you're not moving with regard to one object, you're going to be going at a rattling old pace with everything else in the universe. Or, more correctly, you'll be going at a whole stack of different speeds, depending on what you measure your speed against.

pmcolt
2003-Jul-02, 07:28 AM
Nothing special, I imagine. Velocity is relative to something else, so as long as you aren't accelerating, you can always consider yourself to be at a dead stop.

If you mean what would happen if you were way out in deep space, far from any big gravitational sources, then: still nothing special, probably. If I remember what little I know about relativity correctly, then time will pass slightly more quickly for you than it will for someone in a deeper gravity well (or someone accelerating). Also, you'd probably die from exposure to vacuum, but it's probably for the best, because who wants to live the rest of their life stranded in deep space with no one around?

Kebsis
2003-Jul-02, 08:03 AM
I've actually heard that used to debunk some UFOs. People see little dots that are zipping back and forth, and the debunker would say that since no matter can go from moving to a dead stop, that the ufo must not be made of matter, and is more likely some sort of ball lightning or whatever.

Maybe the question is, what would happen if the object went from movement to a complete stop, relative to itself?

calliarcale
2003-Jul-02, 12:55 PM
Maybe the question is, what would happen if the object went from movement to a complete stop, relative to itself?

Well, you are always at a complete stop relative to yourself. ;) It's the universe that is moving around you. (Sorry, just being pedantic.)

If an object were to come to a complete stop relative to, say, the Earth, what happens will depend on a) how fast the object was travelling, b) what caused it to stop (particularily how the force was distributed), and c) how fragile it is. For instance, if you are travelling at 500 MPH and come to a complete stop, you will be killed. The force neccesary to decellerate your mass quickly enough to be considered instantaneous would also be sufficient to make you go splat. Your body is definitely not strong enough to tolerate that kind of force. In fact, most things aren't and will take some kind of damage.

Consider automobiles.

Imagine a car driving 60 MPH down the freeway. A deer leaps into the road. The driver instinctively swerves to avoid the deer and slams on the brakes. The brakes lock and he loses control of the vehicle. It has not yet decelerated appreciably, but now it is travelling towards a very large and elderly oak tree just off the shoulder. The car hits the tree at about, oh, 55 MPH. Since the tree is rooted much too firmly for the car to dislodge it, the car must stop. But it takes force to change velocity. Remembering that force equals mass times acceleration, and remembering that the acceleration in this case is a change from 55 MPH to 0 MPH in far less than a second, that's a pretty substantial force. It's enough to take the apparently very sturdy steel frame of the car and crush it like a pop can.

So that gives you an idea of what can happen when you decelerate very rapidly. Crashes are a great example of very fast decelerations. Airplanes striking the ground at 300 MPH -- there's often very little left. People striking the pavement after falling from the top of a skyscraper -- you may need DNA testing to identify what's left. And of course this is also why such catastrophic things can happen when a meteor travelling tens of thousands of miles per hour smashes into the Earth. The kinetic energy released when that thing decelerates can be far beyond anything we humans are remotely capable of generating with our technology.

I always thought F=MA should be used as an example of why people shouldn't drink and drive. :D

Russ
2003-Jul-02, 04:05 PM
What would the effect on time and the individual be, if one could bring themselves to a dead stop in space?

Dead stop with regard to what?

There's no universal reference frame in the universe. This means that if you're not moving with regard to one object, you're going to be going at a rattling old pace with everything else in the universe. Or, more correctly, you'll be going at a whole stack of different speeds, depending on what you measure your speed against.

Weeeelllll, that's not exactly true. ;) You could try to have no motion relative to the Cosmic Microwave Background (CMB). Hypothetically if you manuvered so that you observed no Dopler shift in the CMB no matter which direction you look, you could be considered to be at a Dead Stop. Of course, all of the junque in the universe would be flying by at a kajillion klicks a second. It'd be like playing dodge ball a shotgun range. :lol:

Peter B
2003-Jul-02, 11:21 PM
What would the effect on time and the individual be, if one could bring themselves to a dead stop in space?

Dead stop with regard to what? There's no universal reference frame in the universe.

Weeeelllll, that's not exactly true. ;) You could try to have no motion relative to the Cosmic Microwave Background (CMB). Hypothetically if you manuvered so that you observed no Dopler shift in the CMB no matter which direction you look, you could be considered to be at a Dead Stop. Of course, all of the junque in the universe would be flying by at a kajillion klicks a second. It'd be like playing dodge ball a shotgun range. :lol:

Fair enough. Yes I thought about that after I posted.

But even then, can we consider the CMBR a universal frame of reference? I think the BA would say no.

tracer
2003-Jul-04, 12:59 AM
I've actually heard that used to debunk some UFOs. People see little dots that are zipping back and forth, and the debunker would say that since no matter can go from moving to a dead stop, that the ufo must not be made of matter, and is more likely some sort of ball lightning or whatever.
Actually, dots zipping back-and-forth and changing course in an impossible manner are usually one of two things:

1. Insects close up to the camera, or
2. Reflections off the camera's optics, moving around quickly because the camera operator doesn't have perfectly steady hands.