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Einstein's Theory Of Relativity


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You're kidding right?

 

There's a lot to know. Why don't you say what you're having problems with since that would help narrow things down.

 

mwc

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Guest Davka

The extremely simplified Cliff's Notes version:

 

- E=MC2 - E is Energy, M is Mass, C is the speed of light (approx. 186,000 miles per second).

 

This means that Energy, Matter (Mass), and Light are all different forms of the same thing.

 

- The speed of light is a constant, and cannot be exceeded. This means that if you are driving your car at 1/2 the speed of light and turn on your headlights, the light coming out of your headlights will still not exceed 186,000 miles per second.

 

- Time and space are interrelated. One cannot exist without the other. This is commonly referred to as Space/Time.

 

- Space/Time is affected by Mass. Really heavy objects, like planets and stars, distort or "curve" Space/Time. This means that the light from a distant star will be bent if it passes close to another star or planet on the way here: the usual straight line that light travels in will be tweaked a bit.

 

- Time is relative to speed. The faster an object travels, the slower time will seem for that object, subjectively. If you take two super-accurate atomic clocks and synchronize them, then put one on a very fast spaceship and send it, say, to Saturn and back, the clock on the spaceship will show less time has elapsed than the clock that stays on Earth. This has actually been tested with clocks in Earth orbit.

 

There's tons more. Like, really tons and tons. What kinds of questions do you think are likely to be on the test?

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- Time is relative to speed. The faster an object travels, the slower time will seem for that object, subjectively. If you take two super-accurate atomic clocks and synchronize them, then put one on a very fast spaceship and send it, say, to Saturn and back, the clock on the spaceship will show less time has elapsed than the clock that stays on Earth. This has actually been tested with clocks in Earth orbit.

This is also why scientists claim that astronauts age slower when they are in space than someone on the earth. It is only a few seconds I believe.

 

You could toss in how the term got its name:

The term "theory of relativity" was coined by Max Planck in 1908 to emphasize how special relativity (and later, general relativity) uses the principle of relativity. http://en.wikipedia.org/wiki/Theory_of_relativity

 

Good luck.

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Along these lines my ignorant brain was blown away when I learned this:

During the last twenty years, astrophysicists and cosmologist, led by Cambridge University's Dr. Stephen Hawking, have expanded even further our understanding of mass-energy and have explained how mass-energy's seemingly bizarre properties actually solve the riddle of cosmic origins. Hawking and others have described a naturally occurring phenomenon known as "vacuum fluctuation", in which matter is created out of what appears to be perfectly empty space--i.e., out of a perfect vacuum. Scientists have discovered that even in a perfect vacuum, in which all traditionally understood forms of matter and energy are absent, random electromagnetic oscillations are present. These oscillations actually represent a form of energy now called vacuum fluctuation energy, which can be converted into matter in complete harmony with the mass-energy conservation laws. In other words, the "nothingness" of a perfect vacuum in empty space can and does spontaneously produce matter in full agreement with Einstein's long-established laws.

 

If mass-energy cannot be created or destroyed, and if the universe is entirely composed of mass-energy, then the law of the conservation of mass-energy may be extrapolated to this startling conclusion: the universe, in one form or another, in one density or another, always existed.

--David Mills, Atheist Universe (pgs 73-74)

 

Unless I was hung-over that day, I don't remember learning this in college. Matter popping into existence out of a vacuum of 'nothingness' right in the laboratory. That's freaking cool.

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Unless I was hung-over that day, I don't remember learning this in college. Matter popping into existence out of a vacuum of 'nothingness' right in the laboratory. That's freaking cool.

And then you have quantum tunneling too. Another cool thing about QM. Look it up, and especially how it applies to black holes.

 

Anyway, hmm... Quantum doesn't deal with Relativity though. :)

 

I think this link is a fairly easy read to get the gist: http://www.squidoo.com/relativity_explanation

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Unless I was hung-over that day, I don't remember learning this in college. Matter popping into existence out of a vacuum of 'nothingness' right in the laboratory. That's freaking cool.

And then you have quantum tunneling too. Another cool thing about QM. Look it up, and especially how it applies to black holes.

 

Anyway, hmm... Quantum doesn't deal with Relativity though. :)

 

I think this link is a fairly easy read to get the gist: http://www.squidoo.com/relativity_explanation

 

O.K., if I were stoned I wouldn't have made it past the first two mirror examples. That was great, thanks Han.

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Virtual particles as in the Casimir effect only works in a vacuum with two plates atomically close. There is no evidence it works in space. According to the big bang idea, the universe started off quantum size and expanded to over 100 billion light years across without space changing in any way. Where do the endlessly more particles come from? Answer: They don't because space is literally nothing, defined only by what is in it's area.

 

Gravity tunnels out of a black hole. Duh! While gravity only travels at light speed, gravity cannot stop gravity, so no problem with black holes.

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My favorite description of the vacuum being "alive" comes from Alice in Quantumland (amazon) where it describes particles going to the bank and taking out money they don't have. They can take out as much as they want, but the more they withdraw the shorter time they can keep it, so the ones that get really flamboyant and back to normal before they've even left the building.

 

Real science is trippy enough that I've never had an urge to resort to drugs.

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Guest Davka
Thanks! Trying my best, been checking out books, DVDs. Anyone read, Flatland?

Flatland is wonderful! It's my favorite tool for attempting to describe the nature of time and higher dimensions.

 

Hey, you never told us exactly what kind of information they want you to understand. Is it just an overview, or specific details?

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I need to be able to explain these profound theories to a room full of uneducated children, teens and adults!

 

So I need to be able to illustrate what Einstien said in a way they can understand.

 

 

"The reason why the twin on Earth is much older than the twin who has been traveling through space at a high rate of speed is..........."

 

 

Can you fill in the blank?

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Guest Davka
"The reason why the twin on Earth is much older than the twin who has been traveling through space at a high rate of speed is..........."

 

. . . that the faster you are moving, the slower time moves for you.

 

Time and space are connected. They are part of the same thing. When you move through space fast, you end up moving through time slower, and vice-versa. you cannot move through space without moving through time as well. Think of the hands on a clock: in order to move around the clock face, they take a certain amount of time. And as long as the clock is running, moving forward a certain amount of time (say half an hour) will move the hands through space.

 

If you take away time, you can't move. If you take away space, you can't have duration, because it won't take you any time at all to move from "here" to "there" if there is no here and no there. It can seem kind of strange, but really time needs space to exist, and space needs time to exist. That's why they call it space/time, because it's really interconnected.

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  • 2 weeks later...

Cool. And what is the first thing I do? I try to find a word with 5 letters or more... :HaHa:

 

Haha, I actually thought of doing that before I read your post. Now I don't feel like such a dork anymore. :grin:

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O.K. light always travels at 168,000 mps. Even if you were driving a car 60 mph and then turn on the lights! The light would still travel @ 168,000 mps! Why?

That is because the speed of light is constant, it is dependable to always be that speed. Light does not travel at the speed at which we are traveling, light travels at its own dependable and constant speed.

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Guest Davka

O.K. light always travels at 168,000 mps. Even if you were driving a car 60 mph and then turn on the lights! The light would still travel @ 168,000 mps! Why?

 

The speed of light appears to be an absolute limit. The only thing that can travel that fast is light. If you were to drive a car at the speed of light, the car would become light - the matter would change form into photons. Or so goes the theory.

 

The whole idea of "the speed of light" is a bit of a misnomer. Another way to think about it is that light is one form which matter/energy can take. Matter, energy, and light are all different forms of the same basic "thing" (although even the idea of a "thing" can be misleading here). Sort of like solid, liquid, and gas are three states of matter.

 

Here's the deal: everything is made of the same thing. Light, matter, energy, time, space - absolutely everything in the universe is the same basic stuff in different forms. At a very tiny level, a single "unit" of the universe, the smallest possible thing/energy/light particle that can exist, is a quantum. Plural quanta. From the word "quantity." As in "smallest quantity possible." Thus the phrase "quantum physics." Let's call the stuff everything is made of "quantum stuff."

 

So when the quantum stuff of which the universe is made vibrates at a certain frequency, it acts like matter. We can touch it, shape it, accelerate it, decelerate it, eat it, smoke it . . . it's "stuff." At a different frequency, it becomes energy. It can heat things, move things, and otherwise perform work. And at yet another frequency, it becomes light. Light is "stuff" that moves at 186,000 mps. If it slows down significantly, it stops being light and starts being something else. The core nature of light is inextricably linked to its speed.

 

You could also say that light is what we call quantum stuff when it is moving at 186,000 mps relative to other stuff. If it was moving slower, it wouldn't be light, it would be something else. And it doesn't appear that quantum stuff is capable of moving any faster than 186,000 mps. It's just a natural law. It does appear to be possible for quanta to teleport instantaneously over short distances, but that's not the same as moving really fast.

 

Here's an imperfect analogy: When moving through an atmosphere, there are limits to how fast something can move without burning up due to air resistance. There are also limits to how fast something can move without air causing it to lift off the ground, or flip over or whatnot. Similarly, the space/time continuum seems to have limits built in. There is a limit to how fast quanta can travel without becoming light, and there is a limit to how fast light can travel, period.

 

BTW, the speed of light is not set in stone. There's some wiggle-room. When we talk about the speed of light, what is generally meant is the speed of light in a vacuum. Light travels at different speeds through different mediums, but it travels fastest in a vacuum.

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O.K. light always travels at 168,000 mps. Even if you were driving a car 60 mph and then turn on the lights! The light would still travel @ 168,000 mps! Why?

 

Because you can't add to it. You can't stuff anymore speed into the can. It's full. The way I understand it is that there is a limit of time. That is you can't have less than no time in light's frame of reference from your perspective. From your frame of reference light doesn't have anymore time in which to increase it's speed. A clock that is riding on the beam of light is stopped as far as you can tell. Speed is a function of time and distance and it would be impossible to cover any distance in no time.

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BTW, the speed of light is not set in stone. There's some wiggle-room. When we talk about the speed of light, what is generally meant is the speed of light in a vacuum. Light travels at different speeds through different mediums, but it travels fastest in a vacuum.

 

I've understood that the speed of light is dependent upon the medium through which it travels. I'm also aware of an experiment where a ray of light was able to travel 310 times faster than it otherwise could by passing it through some sort of gas. It actually passed through completely before it finished entering somehow. Now, I know that light is malleable by way of the medium, which means that the absolute speed of light cannot be exceeded, merely adjusted by the medium.

 

That said, I'm also aware of a woman who recently was able to bring a pulse of light to a complete halt, then return it to its natural speed and send it on it's way. If what you say is true, then what happened there?

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