dstebbins

Now wait. Hear me out first before jumping to conclusions.

We often take for granted the thought that gravity is a force, but if it were a force, it wouldn't be constant because if it were constant, an object of less mass would accelerate more rapidly than an object of greater mass due to inverse proportionality. Force is mass times accelertion, so if the force were constant, and the mass decreased, then the acceleration must increase. But that's not the case. All free-falling objects in a vacuum affected by the same source of gravity accelerate uniformly.

The only way these two problems could be solved is if you were to say that gravity is not constant, but that wouldn't make sense in Newtonian physics because absolutely nothing about the earth changes, not its mass, not its density, nothing, and according to everything I've been raised to know, you cannot change just one thing in the universe without changing at least one more thing.

And to top it all off, gravity, supposedly a force, is not even measured in Newtons, the standard unit of force. It's measured in the unit of acceleration, 9.8m/s/s, which is what remains constant under gravity, not the force being applied.

So wouldn't it be more accurate if gravity was defined as an acceleration rather than a force? It certainly makes sense to me. Even my physics professor agrees that my logic is water tight.

The equation for force is mass times acceleration. Well, the mass of any particular object is constant throughout the universe, just its weight changes, right? According to this logic, lifting things should be just as difficult in space as it should be here on earth, yet astronauts can lift a fridge with their pinky, and not even the one on their writing hand for that matter. What gives? What piece of information am I accidentally ignoring?

okay, you're just confusing me further. Lepton? Muon? Pion? Wtf?

As you can see, I just got to the rank of Meson. What is a meson in the scientific world? I knew what a quark was, but not a meson.

Blood is a popular way for courts to find criminals because of the DNA. One problem though: Don't blood cells shed their nucleus when they mature? I know there's got to be something else going on because if it weren't they wouldn't use blood as a primary DNA source, but what is it that's going on?

why don't we try syntrivical force? That's a proven alternative to gravity, and if the spaceships are large enough, then it shouldn't take too much velocity to get it up to 1g.

Would it be possible to have some sort of super dense material near the center of the ship to create a mini gravity field? I know it's highly unlikly but could it happen?

theoretically, yes. Practically, no. In order to get the gravity up to 1g, you'd have to have a center equal in mass to Earth, which would be impractical.

Hi

 

As i understand it there was the big bang which created the dimensions up/down left/right forward/back and possible time (although some scientist are questioning whether time exists) and forced the energy into matter which can be broken down again (eg : if u lite a fire). The universe expanded at the speed of light because there was nothing to get in its way.

Outside of the universe there is no dimensions so u cannot see it, u cannot go into it, it is absolute nothingness. If u could go faster than the speed of light to the edge of the universe and kept going u would come back on yourself and then be going inward towards where the big bang started.

 

Thats how is see it anyway.

Dude, you need to proofread your posts before you finalize them. You have no idea how many typoes were in there.

And what is a "quarion"?

yeah, I'd like to know that too.

I understand this. I'm just saying there's a whole crapload of ways to write a proportionality equation. For example, a directly proportional relationship can be written as y/x = c, cx = y, cy = x, or x/y = c. An inverse relationship can be written as c = xy, c/y = x, or c/x = y. I'm just asking if we could use addition in the form of c = x + y or any other manipulation of that equation.

x ~ y means x = c*y. So proportionality means that one value is a multiple of another. The inverse of multiplication is division. That means that inverse proportionality should be x = c/y.

 

Applying that to your question we see that you´re stoned:

From c = x*y => x = c/y.

From c = x+y => x = c - y.

 

Both connections of x and y have the property that for an increasing y, x gets smaller. But proportionality and antiproportionality are more than just this rather weak statement. In fact (anti-)proportionality is already a pretty strong statement about the connection between two values x and y. See it this way: You have reduced the huge amount of possible combinations (x,y) to one degree of freedom: c.

I'm confused. If proportionality doesn't mean as x gets larger, y gets smaller, then what is the definition of proportionality?

I'm currently taking pre-calculus and I'm learning that, when there is a constant c, then the equation of c = xy is the equation for an inversely proportional relationship of x and y. This makes sense, because if x decreases, y has to increase to keep c at its current constant rate.

However, is this really the only inverse proportionality equation? It seems to me that c = x + y would also be inversly proportional, since 7 = 2 + 5 as well as 7 = 6 + 1. Notice how when one goes up, the other goes down, which is really the only requirement for an inverse proportionality relationship.

Am I right, or am I stoned?

makes sense, but what about the danger? Black holes are among the most dangerous phenomena in the universe. We could get sucked up in this black hole by doing this.

Not calling you a liar. I'm just looking for information.

it would still be extremely difficult. Exactly how close to the speed of light are we talking about?

whew, thanks. That's a relief.

okay, I'm going to clear up EVERYTHING! I saw this on a documentary once.

thread-starter, have you ever heard of M-Theory? It's a descendant of the five superstring theories; in fact, it's what you get when you enter the eleventh spacial demension (the string theories merge into one, which we've named M-Theory).

Supposedly, M stands for "membrane," which states that the universe ends far beyond any limits we could ever reach in a practical time frame, and this end is marked by a membrane. All the matter in the universe that is expanding from the site of the big bang will eventually hit this membrane and bounce off, which we have named the great crunch, where all the matter will once again merge and then explode again in another big bang.

Now, on the other side of the membrane, there are other parralell universes that make up the multiverse. These universes might have seperate rules of science; for example, in one universe, gravity may be a force of repulsion rather than attraction. Speaking of gravity, some scientists believe that these paralell universes explain why gravity is such a weak force; it's leaking to our universe from another one, and by the time it gets here, it's just a faint signal.

Nobody knows how many universes make up the multiverse, but scientists believe their membranes might be shaped differently. For example, one might be shaped like a donut, while another is shaped like a long, narrow metal rod.

I know, it's complicated, but I'm just telling you what I saw on the science channel.

I'm an aspiring astronomer/astrophysicist/etc who is about to graduate from high school and go to college. The problem is that I was just searching usajobs.com and monster.com looking for jobs as physicists, but the only ones I could find were "monitering CIA sattalites" or "drug chemists," none of which interest me in the slightest. It made me think for the first time: What if I can't find a job to match my future PhD? Does anyone know where I might find a job as an astronomer or an astrophysicist or a quantum mechanic? Or rather, would I be more likely to land a job as a professor at my university? If so, would I need to double major with a teaching degree like a high school teacher would?

or you can just wait until the summer of 2007.

 

i think there are going to be some man made

black holes by colliding two proton together

near the speed of light.

 

if successful we then could have a better understanding

of inverted light... j/k

 

LOL

that's impossible. According to the theory of relativity, nothing except light can ever attain the speed of light because then it's kenetic energy would reach infinity, which is unattainable.

Fair enough.

Besides, anyone got a better plan?

That's not quite 100% true, there are researchers who study the molecular interactions between surfaces to try to predcit friction coefficients. Suffice to say, however, this kind of research will be well beyond a high school level physics class. And, the experiments needed to measure the coefficient of friction are rather easy and cheap to set up and perform, so in all practical cases, testing will be the way to find out the answer.

What are you saying? Are you saying that I'm too stupid to understand it?

Uh huh. Care to give us the math behind that estimate?

I saw a documentary about it. It was the same documentary that I heard about the problem with the lack of gravity.

In order to maintain their current physical shape, an astronaut must undergo seven to eight hours of vigorous excersise a day.

They showed a man in a spaceship sprinting so hard that he was straining. You could see it in his face. His teeth were gritted, his eyes were blood red, and his face was as red as a fat basketball player, and he was in rather good shape as well, because he wasn't wearing a shirt, and you could see the muscle tone.

Want to know NASA's amazing solution to this problem?

 

Springy tethers

 

Hook yourself up to them and run on treadmill. The force you exert every step you take is reflected by the springiness of the tether, so you bounce up and down on top of it.

 

Yes, that's NASA's amazing secret to artificial gravity. Springy tethers.

I've seen that before. The problem with that is that it only kicks in when you're running on the treadmill, so you'd have to excersise vigorously (and by that, I mean as hard as you can) for about eight hours a day with no breaks in order to come close to maintaining your current muscle and bone mass. This just isn't practical for anyone other than pro astronauts, not regular people like on Star Trek. Sorry, but if my idea of magnets won't work, that brings us back to square one.

By the way, I figured I should clear up some miscommunications. As for the stuck to the wall problem, the walls would be the same charge as the clothing, so they would repel. You could have a remote with a neutral charge and a magnetic sheild (to protect the computer inside) that would demagnetize the walls in case you needed to approach them, and helmets and shirts would be much stronger magnets than boots and pants, so as to simulate constant resistance. As for the magnetic clothing sticking together, that's a fairly simple solution: Make the clothing short enough so that the magents of different articles don't touch each other. The ripping up the clothes could be solved by simply making more durable clothing than cotton and nylon that we have here on Earth, kind of like that mettalic clothing that we see aliens wear in science fiction movies.

Long-term space residence has long been a "maybe one day" dream of Nasa's, simply because the lack of gravity makes it very difficult to excersise in space, so people's muscles and bones would gradually deteriorate (it's amazing how much excersise you get just sitting here resisting your own body weight).

However, there are other forms of resistance besides weight due to gravity. A good example is magnets. Magnetic charge is much stronger than gravity, as is demonstrated when you hold a magnet a few inches above a metal pen and the pen jumps up to the magnet. Maybe we could make small chips of magnetic metal in all the astronaut's clothing, and make the floor the opposite charge so you are constantly resisting being thrown to the floor, just like, here on earth, you are constantly resisting gravity pulling you to the ground and crushing you. The magnets would be rather diluted, so we don't get too much more than one g.

Am I thinking right, or is there some other complication that I'm not aware of?

I'm in high school, taking physics as an elective. We just got through talking about coeffecients of kenetic friction (when c=coeffecient, f=applied force, and w=weight, then on a horizontal plane, c=f/w). Different pairs of surfaces create different coeffecients of kenetic friction; for example, sandpaper and steel have a greater coefficient than ice and soap (duh).

My question: Is there any way to predict what the coeffecient between to surfaces without pushing someone over a horizontal surface and without just memorizing the coeffecients?

What do you mean by " if gravity is just the result of an object attempting to squeeze itself into "spacetime""? If you are using an analogy like that the closest you could have would be it pushes spacetime away (even though I don't think it happens like that) creating a curve.

 

If you believe relativity its the distortion in space time its self. Anything within the influence of the distortion can feel its gravitational effects. If we are above and object and fall towards it we can be described as "sliding down the gravitational distortion in spacetime". Sorry, I'mnot very good at explaining things.

And I can see why. Sorry for any offense, but those English skills need work.

But if the object isn't squeezing itself into spacetime, then what is causing this distortion?