Why Witch Sabrina Looks Thinner While Riding On Her Broom.

[Thumpalumpacus]

Since obviously you're an ignoramus in matters of math and physics, and incapable of discerning someone like solitary, who knows physics on a superficial level from someone who knows the subject deeply at a level you can't even phantom, I thought giving you a hint would help with a not-so ''irrelevant blogposts''. Apparently, it didn't help.

As to your point on moral equivalence, the genital mutilation stems from ignorance, something you seem to be very familiar with. You're looking at moral equivalence, I'm looking at the source of what causes so much suffering and injustice.

Treating them identically because they share the same wellspring is stupid.  One hurts your little feelings online, and the other inflicts lifelong physical harm.  

Thanks for playing, and stick to physics ... because you clearly have issues  assigning moral valuations.

[Solitary]

If length contraction and time dilation are a figment of the imagination, then the whole theory collapses. You can't cherrypick only what you like and discard what you don't. The theory comes as a whole package.

The next thing people like you will say is that E = mc[sup:r77g0hz6]2[/sup:r77g0hz6] is a figment of the imagination... hmm, just a reminder:

[ Image ]

I never said it is a figment of the imagination. Don't put words in my mouth that aren't there! You don't understand that length contraction is apparent from a measurement that is relevant to an observer, not that it actually does in reality. As for time, isn't it obvious from the theory that time is "RELEVENT" to each observer also? In the theory there is no past, present, or future, accept relevant to an observer and their speed.  You may know math, but you sure don't understand the theories of relativity very well. I'm talking about in the real world and measurement, not in the world of mathematics. Solitary

Measuring the time dilation of the muon's half-life is real, NOT APPARENT. Like I said, you can't cherry-pick. If time dilation is real, so is length contraction, as time and space are on equal footing, a principle that has been successfully incorporated in QFT. You can spin all the philosophy you want, but the physics is real.

"Measuring the time dilation of the muon's half-life is real, NOT APPARENT"

Are you so dense you don't see you are saying your measurement relative to you is real and that the muons time relative to itself isn't . Do you think the muons time it would measure on its clock would be the same as yours? then you don't understand the concept of relativity. Also, according to a muon, if it could, would see your time on your clock different than you do.  :roll:  Did you even watch the video I provided? Solitary

[Solitary]

Since obviously you're an ignoramus in matters of math and physics, and incapable of discerning someone like solitary, who knows physics on a superficial level from someone who knows the subject deeply at a level you can't even phantom, I thought giving you a hint would help with a not-so ''irrelevant blogposts''. Apparently, it didn't help.

As to your point on moral equivalence, the genital mutilation stems from ignorance, something you seem to be very familiar with. You're looking at moral equivalence, I'm looking at the source of what causes so much suffering and injustice.

Treating them identically because they share the same wellspring is stupid.  One hurts your little feelings online, and the other inflicts lifelong physical harm.  

Thanks for playing, and stick to physics ... because you clearly have issues  assigning moral valuations.

He doesn't know physics very well either, he just knows the math. Logically a contradiction shows too things can't be true. This paradox in observation and measurement of time and length when approaching the speed of light is the very reason Einstein came up with the Special theory of relativity to solve the problem.
"solitary, who knows physics on a superficial level." That's funny because it is obvious that it applies to you. Just because you know the math doesn't mean you know the reality of relativity. Solitary

[Solitary]

The Theory of Relativity for Dummies

Most people think it was Einstein who, in the first decade of the twentieth century, came up with the theory of relativity – as if Albert was quietly working away in his patent office in Switzerland and, entirely on his own, managed to come up with a completely new theory of space and time. Actually, it wasn't quite like that, but because the history of science is a dreadfully tedious subject, we will skip Albert's many predecessors and get straight to the best bits of the theory of relativity.

Question: Why is it called a theory of RELATIVITY? Why indeed.

Because time and length are no longer absolutes. You've got your digital watch on your wrist and a metre ruler on your desk. These seem like absolutes: a second and a centrimetre for you must be the same as they are for me, and the same as they are on Alpha Centauri. But they're not.

If I stay on my balcony while you start a career as an astronaut flying round the galaxy at an incredible speed (and it would have to be pretty close to the speed of light: 300,000km/sec), and if you could later whiz past my balcony so that we could somehow compare watches and rulers, your metre ruler would be smaller and your watch would be going slower than mine. (Actually that wouldn't be possible because the human eye can't spot things moving at that kind of speed, and spaceship rockets do nasty things to balconies that are only a few metres away. But if it were practically possible, it would be fun.)

While you're out in space travelling at some unbelievable speed nothing seems to you to have changed. It's only if you have a chance to compare measurements of time and length with those back home that you see that something odd has happened. Take time to think about this.

Q: All the introductions to Einstein talk about the twin paradox. What's that?

One 25 year old twin stays on earth while the other, fresh out of astronaut school, sets off on a space voyage travelling at 90% of the speed of light. After 10 years in space, with her mission accomplished, she turns round and heads back to earth. By the time she lands she knows from her on-board clock that 20 years have passed. She is now 45 years old. Fortunately, her study of relativity has prepared her for the shock when she sees her twin sister, who is now 71 years old. This is according to the general theory not the special theory.

Conclusion: Space travel, when it is really, really fast, is also time travel: you travel into the future without getting that much older yourself. Think about that!

So is everything relative?

Not exactly. Actually, the idea of time and length being relative to our speed was proposed first as a way of explaining an observation that puzzled everyone.

Some people in the nineteenth century devised a very sensitive piece of apparatus to measure the speed of light as we on earth rotate in space. The idea behind the experiment is easier to grasp if we think of spacecraft and the tiny particles of light called photons. If you were accelerating away from the sun wearing special goggles that enabled you to see individual photons, as you approached 300,000km/sec you would expect to see photons moving ever more slowly past the side window of the spacecraft. And common sense would say if you put your foot on the gas a bit more, you should overtake the photons and leave them crawling along behind as your spacecraft exceeds the speed of light.

What the scientists discovered, to everyone's surprise, was that if you move faster, light doesn't whiz past your window more slowly. It always whizzes past at the same speed. (In other words, the photons always win – nothing travels faster than light.)

To explain this bizarre finding, scientists (even before Einstein) suggested the following: the result only makes sense if, the faster you travel relative to the speed of light, the shorter your unit of length becomes and the slower your measurement of time becomes. This is to an observer in a different set of coordinates.

To an outside observer looking at your superfast starship, the photons might be moving past your side windows really slowly as your speed approaches 300,000km/sec, but if your on-board clock has slowed down by the same amount and your measurement of length has been compressed those same photons seen from inside the starship will seem to be whizzing past at the same speed as they had when you were still in first gear. Compared to an observer in another set of coordinates.

Is there any proof for all this?

Yes. Although spacecraft are still way too slow for astronauts to notice the effects of relativity, research into the behaviour of subatomic particles gives clear support to the theory. There is a laboratory deep within a Swiss mountain where they watch what happens to subatomic particles as they whiz through a circular tunnel attaining speeds close to that of light. Weird things happen, such as unstable particles staying alive for a lot longer than they normally would, and these weird things can only be expained by the theory of relativity. This is relative to an observer in a different set of coordinates.

Introduction to relativity: part 2

Q: I want to live as long as possible. Can relativity help me?

Time ticks by more slowly if you travel really fast, but this won't help you to enjoy living longer. On the spaceship nothing seems to have changed. If you make it to 80, despite all the health risks of space travel (osteoporosis, exposure to some really nasty radiation, etc) you will still look old and wrinkled. You would, however, be able to come back to earth and find that you had lived longer than your old mates (now at peace in the cemetery) but that doesn't sound like fun, so those who want to live longer would be better off sticking to a healthy diet and regular exercise, coupled with marriage and a sincere belief in God (on average, married believers live longer than unmaried atheists).  :Hangman:  Right, and they think they will never die.

Is there just one theory of relativity?

Unfortunately, there are two. The earlier one about space and time and the speed of light is known as the special theory of relativity. Later, Einstein realised he had made a few important omissions: gravity and acceleration (which turned out to have some striking similarities). So he developed the general theory of relativity to add to and complete the earlier theory. Again, Einstein wasn't the first to say some pretty weird things about light and gravity and space, but we're not going to bother with the boring historical details.

 Let's concentrate on the weird stuff.

What's weird about reality according to the general theory of relativity?
Well, for one, space is curved.

Eh?
If space wasn't curved, whenever we shone a beam of light (like a laser) it would travel in a line that would seem perfectly straight from wherever you were in the universe, and it would go on for ever and ever in the same direction. This is exactly as Euclid would have predicted (Euclid being the ancient Greek guy who was the founding father of high school geometry, and who assumed that space just had to be flat). This is not what happens, though. Light is bent by gravity, so a beam of light passing through galaxies curves when it comes close to a strong gravitational field.
 
Some people even think that gravity bends the space of the entire universe into a huge sphere. In practise, this would mean that if you tried to shine a laser beam out beyond the edge of the universe, gravity would bend it and send it in a huge circle running round the perimeter of the universe. (There would be no way of looking beyond or travelling beyond the edge of a universe like this.)
 
Is that about as weird as it gets?

Not exactly. The theory predicted (not for the first time) the existence of black holes. If gravity bends light then it is possible that if a star became dense enough, its gravitational field could be so great that the light it previously emitted could no longer escape.

Eh?
Let's begin like this: To launch a spaceship from the surface of the earth, it has to reach a velocity of about 40,000km/hour (11km/sec) otherwise gravity will either pull it into an orbit or back to the surface of the earth. This escape velocity increases relative to the size of the planet or the star (or even the galaxy) and its density. From the surface of the sun (much bigger and slightly more dense) the escape velocity would be 624km/sec. That would cause problems for terrestrial spacecraft but it causes no problems for light (travelling at 300,000km/sec).

When stars reach the end of their life strange things start to happen and they start to collapse. Eventually the atoms are squeezed together so tightly that their nucleii start to touch one another. That makes collapsed stars incredibly dense, the consequence of which is an incredibly strong gravitational field. If this were to happen to our sun, and if it were to become so compact that its diameter were a mere 1.47 km, gravity at the surface would be so high that the light of the dying star would no longer be able to escape.
As one physicist put it in the 1920's:

"There could come a time when the sun is shrouded in darkness, not because it has no light to emit but because its gravitational field will be impermeable to light."

The sun would have become a black hole.
Hang on. If a collapsed star can become a black hole, black holes can't really be holes, can they?
True. Actually, they weren't originally called black holes, and the word "hole" is a bit confusing because it makes you think that there is really nothing there, which isn't true because there is only a black hole when there is something which is either very very big or very very dense.

Another thing. Didn't you say light always travels at 300,000km/sec? Now you tell us that gravity makes light travel more slowly and could even bring it to a standstill.
 
If you were somewhere near a black hole and you measured the speed of light coming from your on-board laser, you would be disappointed to find it was still travelling at the usual speed. This is because gravity also does weird things to the clocks and rulers you would use to measure the speed of light. Close to very strong sources of gravity clocks tick away more slowly and rulers shrink (not that you would notice this inside the spaceship). These distortions of time and space are what they call a warp in spacetime. All to an observer outside a black hole.

If black holes do weird things to clocks, could they help me live longer?
If you could find a nearby black hole that was spinning, you could fly your spaceship into the whirling ring of material around it, and then with a quick burst from your booster rockets you could pull the ship out of the orbit before it got sucked into the blackness. Your on-board atomic clock might indicate that the hair-raising trip just lasted a couple of hours. But back on the mother ship hundreds of years might have elapsed. Again, all your old mates would be dead, which isn't much fun.
 
However, there is a happier lesson to be learnt for those of us back on earth. You should bear in mind that clocks tick slower in stronger gravitational fields when you next look for somewhere new to live. Physicists have put atomic clocks (that can measure a billionth of a second) in the basements and on the top floors of skyscrapers, and they have proved that clocks in basements run more slowly. So you should stop looking for a room with a view, you should get all your mates together and share one big flat underground.
As compared to another clock in a different set of coordinates.  This is why time is not absolute but relative to an observer and their speed.

[WitchSabrina]

Sorry to have a blonde moment - but HOW can math be a debate?  Isn't math.......  math?

[Solitary]

Sorry to have a blonde moment - but HOW can math be a debate?  Isn't math.......  math?

Math is not debated, but whether a measurement of time and space is relative or not. I say it is, and JosephPalazzo thinks its not that it's real time dilation and not just a reading on a clock by an observer and actual shrinkage of a solid object instead of a measurement by an observer.

This means you are not really thinner, but it just appears to be so when you zip past on your broom to an observer standing still compared to you, and if the observer was going with you on his broom  =P~  he would see you as you really are which is lovely. :shock:     Sorry! Solitary

[josephpalazzo]

Since obviously you're an ignoramus in matters of math and physics, and incapable of discerning someone like solitary, who knows physics on a superficial level from someone who knows the subject deeply at a level you can't even phantom, I thought giving you a hint would help with a not-so ''irrelevant blogposts''. Apparently, it didn't help.

As to your point on moral equivalence, the genital mutilation stems from ignorance, something you seem to be very familiar with. You're looking at moral equivalence, I'm looking at the source of what causes so much suffering and injustice.

Treating them identically because they share the same wellspring is stupid.  One hurts your little feelings online, and the other inflicts lifelong physical harm.

And who says I'm treating them equally??? Before writing stupidities, use your head, if you have one!!!

Thanks for playing, and stick to physics ... because you clearly have issues  assigning moral valuations.

Don't thank me, you're the idiot who blurped some idiocy regarding my post. Next time, mind your own business if you can't make some intelligent comment. You're a waste.

[josephpalazzo]

Solitary, your post is full of so many errors, that I won' bother with it. The only advice I have for you is to study the theory from textbooks that have stood the test of time, and not from the internet.

Here's a partial list ( I have these books myself):

A First Course in General Relativity [Hardcover]
Bernard Schutz

General Relativity [Paperback]
Robert M. Wald

Gravity: An Introduction to Einstein's General Relativity [Hardcover]
James B. Hartle

Gravitation (Physics Series) [Paperback]
Charles W. Misner, Kip S. Thorne , John Archibald Wheeler

If you don't want to spend that much money, you can use Sean Carroll online lecture notes at:

http://arxiv.org/pdf/gr-qc/9712019.pdf

However, it won't give the overall perspective when you study a subject from different authors. But Carroll's notes are better than nothing.

[Solitary]

http://arxiv.org/pdf/gr-qc/9712019.pdf

This lecture is of the relationship of the special theory of relativity with regards to spacetime, not the theory itself.  :roll: Why do you insist in complicating the issue at hand with mathematics instead of plain English?

The idea that time being relative lies at the very heart of Einstein's special theory of relativity. You may think that time is fixed, that it can't slow down or speed up---especially external time. But Einstein would disagree.

Time passes differently for a person at rest than it does for someone at a great speed in "RELATION" to the person standing still. But for both people, "their" experience of time is real time. Neither of them is aware that time is passing by differently for them.

Now lengths don't change for a person approaching the speed of light. For them, objects appear to be the same length as always. The change is "PERCIEVED" by an observer who is watching an object approach the speed of light. remember that the special theory deals with two frames of reference: the person approaching the speed of light and an observer at rest.

Almost all of the "paradoxes" associated with SR result from a stubborn persistence of
the Newtonian notions of a unique time coordinate and the existence of "space at a single
moment in time." By thinking in terms of spacetime rather than space and time together,
these paradoxes tend to disappear.

The concept of absolute time was overthrown by the special theory of relativity, in which time was no longer an independent quantity on its own but was just one direction in a four-dimensional continuum called spacetime. In special relativity, different observers traveling at different velocities move through spacetime on different paths.

Each observer has his or her own measurement of time along the path he or she is following, and different observers will measure different intervals of time between events. Thus in special relativity there is no unique absolute time that can be labeled for events. However, the spacetime of special relativity is flat. This means that in special relativity, the time measured by any freely moving observer increases smoothly in spacetime from minus infinity in the infinite past to plus infinity in the infinite future.

So the bottom line is that Sabrina on her broom will be "perceived" to be thinner by an observer standing still when in fact she won't be.  :P  Solitary

[Plu]

Sorry to have a blonde moment - but HOW can math be a debate?  Isn't math.......  math?

There's actually a number of debates going around in the world of math about a number of topics that simply aren't very clear-cut. Math is not unchanging, nor unique, and has its own debates. Particularly in the field of infinity as I remember, there are a lot of divergent opinions on how it should work.

[WitchSabrina]

Sorry to have a blonde moment - but HOW can math be a debate?  Isn't math.......  math?

There's actually a number of debates going around in the world of math about a number of topics that simply aren't very clear-cut. Math is not unchanging, nor unique, and has its own debates. Particularly in the field of infinity as I remember, there are a lot of divergent opinions on how it should work.

Actually, I'm not that simple minded Plu.  LOL  I was trying to make a joke and ease the conversation.  But I agree math is not unchanging.  
cheers

[Plu]

Ah, ok :P It's hard to tell sometimes. Plenty of people really think like that.

[Jason78]

Why do you insist in complicating the issue at hand with mathematics instead of plain English?

The maths actually makes it easier to understand.

[Solitary]

That like saying explaining something in Greek makes it easier to understand.

There is a very simple way to resolve this debate. All Joseph has to do is show us in his own words, like I have, what the special theory of relativity is about, or even post from one of his books he listed what it says, and not a bunch of mathematics that most people don't understand.  :roll:  Solitary

[josephpalazzo]

http://arxiv.org/pdf/gr-qc/9712019.pdf

This lecture is of the relationship of the special theory of relativity with regards to spacetime, not the theory itself.  :roll:

This is where you show your upmost ignorance. I'm not going to bother with you.

Read the first page:

These notes represent approximately one semester's worth of lectures on introductory
general relativity for beginning graduate students in physics.