damn… Advise should be Advice…
BZ, As to the other book:
You will learn alot more from the one I mentioned. Plus, you will need what is in my book to really understand what is in the one you mention.
BZ0000, if you’re planning on making a serious attempt at time travel, I recommend this traveller’s guide. It should help you plan for any paradoxes you might happen upon during your journey.
Yeah, it was like “beep beep beep beep beep beep” and then, like, half of my time was gone…and I was like, “Nnh?” It devoured my time…it was a really good time…and then I had to live it again, and I had to do it fast, so it wasn’t as good. It was kind of…a bummer.
I’m BZ00000 and I’m a Time Traveller.
you cannot reverse time by spinning the earth backwards.
if the earth did begin to spin backwards at terrific speeds, all that would happen is that people would shit themselves at the sight os the sun moving the wrong way across the sky. It would not make anything work in reverse, except for sundials.
It would probably play havoc with the weather and tides, for a time at least.
scotth, I bought the book at lunch today. Before I start reading, can you the broadest terms explain what Einstein’s theory of relativity is? What is special relativity?
Special Relativity is a “reformulation” of physics to take into account some of the perplexing and interesting discoveries made about light in the years preceding.
A simple example involves the classical idea of addition of speeds. For example if you were on a train going down the side of a highway and watched the cars going by (in the example) exactly 60 mph in both directions. If the train is moving at 30 mph, you would see cars approaching from the front at an appearent 90 mph. If you watch cars approaching from the rear, the would approach at the appearent speed of only 30 mph. (I am ignoring receding cars). Applying the same reasoning, one would expect the speed of light to be measured as c +30 mph if it was coming in towards the front of the train and c - 30 from the rear. This doesn’t happen, and in fact it was discovered that measured from either end of the train (or actually looking in either direction more accurately) that the speed of light never deviated from c. Very confusing for the people making the measurements.
The solution was to make the declaration that “speed of light is constant to all observers in every situation” and that the pace of time and size/shape of space (always considered before rigid before) is what must give. With this assumption he “rewrote” all the existing laws of physics to take this idea into account. What he got was a theory that made some very interesting (and contrary to common sense) consequences. When compared to reality through experiement, the new statement of physical laws matched beautifully with every measurement, and when the bizzare predictions were checked out, they were correct as well.
Special Relativity does not address gravity.
General Relativity extends and completely encompasses Special Relativity and adds gravity as well. It brings up a few more pretty bizzare consequences and when we looked close we found them all to be true as well within our limits of observation.
If you wind up with even a passing understand of relativity, you will have a significantly better understanding of the world in which you live.
If you make it though Maxwell’s equations and really understand them and never make to relativity, even this will open huge vistas of insight into the world around you.
I can tell you, and doubt many would dissagree, that the very moment when the ideas of Maxwell’s equations became clear was something that could easily be describe as a “religious” experience.
Nametag, I must apologize for totally screwing up your pit thread with my continued addressing of BZ’s questions.
Really, I am serious… not a drop of sarcasm in this.
I completely understand/understood your frustration when opening, and it was pretty well deserved ranting.
I guess I just can’t help myself when I see the possibility of salvaging another “rusting” brain. Of course, I may come quite to regret my offer to BZ.
So again, sorry for interupting a well deserved rant with factual stuff belonging in GQ.
Ok, I have a question about what you just wrote. How can the appearent speed of light appear to be the same?
Let me use your example. If something is moving at the train at the speed of light is doesn’t matter if it comes from the front of the the train or the back, the speed of the object will appear to be the same? Does this mean the that from a fixed distance from the train it will take the same amount of time for the object moving the speed of light to reach the train from either drection? Despite the fact the train is moving?
Ya know, I think this is the first time I’ve seen a pit thread degenerate to a GQ thread instead of vice versa.
Everyone may disagree on the timing of an event if everyone is moving at a different speed, but the speed of light will appear the same to all people. Actually, your whole concept of simultanous will need to be reworked.
Don’t worry about it for now, it will just be putting the cart for the horse. It will help (alot) to undertand the preceding material… that is why there is 300 pages of it in the book before you get to heart of the matter.
Hats of to you, Sir scotth. I hereby appoint you Knight of Light.
Yeah, first time I’m seeing a Pit thread “degenerate” into GQ territory. I think that fact alone gives Sir scotth an extra 1000 points.
And here’s a random thought:
*There’s a light at the end of the tunnel…
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… it’s the light of an oncoming train. Help!"*
I formally request a “Ask The Relativity Guy” thread.
Question-
We all know that E=MC[sup]2[/sup] .
But, I’ve been wondering if it’s also true that E % C[sup]2[/sup]=M .
Cuz, I’ve got plans for a bomb that converts massive amounts of energy into a little bit of matter. The fact that such a bomb would be useless only inspires me further.
In spite of myself, I keep thinking of the Superman movie scenario. Obviously, reversing the rotation of the Earth wouldn’t reverse time, but what would be the effect of Superman flying around the planet at great speed? In real life (assuming a being of Superman’s vast powers existed) he couldn’t exceed the speed of light, but let’s assume he could get pretty close to it (though still requiring infinitely more energy to get there).
As he gets closer to lightspeed, his mass increases. Suppose he went fast enough to acquire planetlike mass. (I’m too lazy to figure out how fast that would be, but in the same movie he gave his weight as about 220 pounds, in case anybody else wants to do the math.) Never mind the mind-boggling amount of energy required to move that kind of mass around in a 8000-9000 mile diameter circle at nearly the speed of light. What would be the effect on the Earth? The enormous tidal forces would actually have an effect on the planet’s rotation, but also I imagine the crust would pretty much melt, and little Jimmy Olsen would die. So, sadly, would Miss Tessmacher.
Bummer.
The do it all the time in particle accelerators. Take a couple particles and add lots of energy (speed). Smack them head on in a collision and get particles with much more mass out than supplies by the mass of the original two particles.
I would love to see an idea of how you this conversion to go in a self sustaining manner.
Ok, I have a question about the book. On page 23, figure 14, what is this graph showing. I know it is uniform motion, but what do the x and y coordinates represent? What is this figure showing?
This graph represents 3 dimensions. That is just the best you can showing 3 dimensions on a two dimensional paper.
The graph shows motion in a plane (uniform as you say) over a period of time.
The x and y coordinates are just the same as you saw in high school, just imagine the x and y plotted on a paper laying on the desk with the t axis sticking straight up out of the table.
A very good way to imagine this graph: Have you seen cartoon books where you can flip though the pages to see the cartoon? Assuming yes, now picture that you replace the cartoon with just a dot that moves around the book in some pattern as you flip the pages. If you made the pages out of clear plastic, you could see through the book and see the path rising vertically as the dot wanders around the pages.
A page would contain the x and y axis, and stacking the pages would get a t or time axis.
Now, what the graph actually shows using the transparent cartoon book idea as an illustration.
- If you were looking straight down over the book, you would see a dot move from the lower left to the upper right as you flipped the pages and that is all.
- If you closed the book and looked from a side angle through the clear plastic pages, you would the spot appears as a line rising as it moves to the upper left of the book.
- The line from 0 that goes up above the numbers 1, 2, 3, and 4 would be that same line.
- Each page would be a slice of time.
That help?
Thanks.
That was a pretty clumsy explanation for something that is very easy to show when you can use your hands and point in different directions.
If that didn’t really help, let me know, I will explain another way, or make a little movie with one of my 3d packages (don’t worry, it is really easy) that will make it crystal clear.
Reading these graphs will be very important in a few pages.
No, wait, I’m still confused.There is the x,y, and t cordinate system and then inside is another set on lines with more lines inside and the numbers 1, 2, 3, and 4. What is the top inside line, what is the bottom inside line and what do the numbers 1,2,3, and 4 represent? Are the number seconds?
Thanks for your help.