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rwald
4th March 2003, 04:27 PM
Relativity.
Hard to explain in haiku.
But I think I'll try.

First, there's "special;" it
Has no acceleration

For all observers
Who aren't speeding up or down.
Physics is the same.

Imagine two guys
Floating out in open space.
They're named Al and Bert.

If they move apart
Does Al move, or is it Bert?
There's no way to tell.

Al could take a lamp with him
And then turn it on.

Light travels at c.
Al can compare self to light.
To find his speed, right?

Nope, that would not work.
Light always travels at c.
For all observers.

What? You do not care?
This fact changes many things:
Classic example:

We have a train car.
Two leaders at front and back
Plus there's a table.

Now, they want to sign treaty
At exact same time.

So, here's what they do:
They put light bulb on table
Half-way in between.

When they see the light
Then they will sign the treaty.
Will be the same time?

An observer on
The car would say both leaders
Signed at the same time.

"The light left the bulb,
Traveled exact same distance
Reached ends at same time."

But, an observer
Sitting beside the train tracks
Wouldn't agree to this.

"After light turned on
The train was still moving fast
Distances were changed.

Moved closer to where bulb was
He saw the light first."

So, which one is right?
The answer is both of them.
Not intuitive.

So, time's relative.
It moves differently for some
Than does for others.

Also, without time
Length and mass are relative
Only c's constant.

That was the "special"
Type of relativity
Now, for "general."

So, you cannot say
Whether or not you're moving.
But that isn't all.

You also can't speak
Why? Let me explain.

To put it simply:
Gravity accelerates
Just like space ships do.

More complicated:
Imagine a fast space ship
With you inside it.

You feel a pull
Towards the bottom of your ship
Just like gravity.

What's making this pull?
It is the whole universe.
As it goes past you.

Same with centrifuge:
The whole universe revolves
Around the sample tube.

Neither you nor tube
Can say if they are moving
Or the universe.

When you are moving
Space-time gets "warped" around you
Warping makes the pull.

Same with gravity.
A large mass will warp space-time.
And create a pull.

"What is this 'space-time'?"
It is hard to understand.
I'll try to explain.

Usually, when
Things travel, they move in a
Perfectly straight line.

However, mass or
Acceleration can cause
A straight line to bend.

If you travel near
A large mass, you'll see your ship
Won't move in a line

Rather, it will curve
Around the large mass. This is
Because space-time bent.

In three dimensions
Your ship traveled in a curve
But not in space-time.

In four dimensions,
Your ship took the shortest path
That space-time allowed.

This is how orbits
Work; we're just moving through a
Bent-up space-time field.

Of course, there are some
Other cool effects of this:
Black holes, time travel.

But I will leave those
For a second discussion
I'll have an encore!

(If you liked this post
It's interesting.

"Relativity
Explained using words of just
Four letters or less.")

Skeptoid
4th March 2003, 05:35 PM
Einstein's equation
E=mc<sup>2</sup>
Is simple, yet deep.

rwald
4th March 2003, 05:38 PM
Hi again Skeptoid,
What that lacked in lenght it made
Up in elegance.

(Seriously, though
A huge long post like mine is
Just no match for yours.)

Samus
4th March 2003, 06:46 PM
Sometimes I'm amazed
Just how much time people have
On their hands these days

Relativity
In haiku is strange indeed
But I think it's neat

Kudos go to you
With such elegance

4th March 2003, 07:04 PM
Commendable, sir!

4th March 2003, 08:25 PM
Standing Ovation
That was most intense.

BillyJoe
6th March 2003, 02:43 AM
All is forgiven,
rwald. We are friends again.
regards, BillyJoe.

rwald
6th March 2003, 04:19 AM
I have forgotten,
When were we not friends? Always
I respected you.

BillyJoe
6th March 2003, 04:26 AM
Perhaps I am wrong.
Didn't you call me a troll

rwald
6th March 2003, 04:32 AM
I don't recall that.
I'm sure it is possible.
If so, I'm sorry.

BillyJoe
7th March 2003, 04:18 AM
"Bidlack" was a joke.
The thread this is, not Bidlack.
No one understood.

They called me a troll.
"Borb the lot of them" you said.
It felt personal.

tim
7th March 2003, 12:07 PM
Rwald I am truly gobsmacked! I applaud your poetry and intellect!

rwald
7th March 2003, 01:52 PM
When the Borb forum
Was first created, I said

I have sometimes been
Known to not understand jokes.
This could explain it.

Just for the record,
What is that thread's exact name?
I am curious.

In any event,
I think that we both agree.
That no harm was meant.

BillyJoe
8th March 2003, 04:43 AM
I told you: "Bidlack"
That was the name of my thread.
An innocent joke....

As you may recall
Bidlack created the forum
"Bogus or Brilliant"

Into this forum
He dumped all the nonsense threads
That litter our site.

I challenged Bidlack
To trash "Bidlack". In effect
To trash himself but.....

He missed the joke
And sent it to "The Flame Wars".
Thinking me a troll.

rwald
8th March 2003, 07:25 PM
Ah, now I recall
The thread to which you refer.
Thanks, I get it now.

Incidentally,
I can't find a link to it.
It is curious.

I looked at the board.
Viewed "all" and sorted by name.
It still wasn't there.

BillyJoe
8th March 2003, 11:36 PM
'Twas in flame wars as I said.
Listed on page one.

I think I agree with you,
That no harm was meant.

rwald
10th March 2003, 02:34 PM
It was in Flame Wars?
Than that explains the problem.
I looked in the Borb.

BillyJoe
11th March 2003, 04:09 AM
We've done haiku in.
The five seven five pattern.
And now we've finished.

12th March 2003, 06:46 PM
I always cringe when I see this....Nope, that would not work.Light always travels at c.For all observers.
This is only true when in a vacuum.It is so often misquoted by leaving out the vacuum part.

rwald
12th March 2003, 07:06 PM
Yes, you are correct.
If I recall correctly,
Some tests have changed speed.

One that was quite cool
Involved some kind of crystal
Normally opaque.

By using lasers,
They allowed light to pass through
At a slower rate.

Thirty-seven miles per hour.
Cars can drive faster.

And I must include
Some even more startling tests
Which increased the speed.

I heard that some have
Sent light at two or three c.
It might have been more.

Does it really count
If light travels faster than
C, the speed of light?

Yea, it's above c.
Which should be impossible.
But, it's only light.

I mean, isn't the
Speed of light defined as the
Speed at which light moves?

Light cann't exceed that.
Even if above c, it's
Not faster than light.

Anyway, the point is that
I know that the speed of light
Can sometimes be changed.

However, for the
Purposes of my haiku.
This did not matter.

garys_2k
12th March 2003, 07:54 PM
Light moved faster than c? What experiments were those? I ask because doing so would imply quite a space-time wrinkle, as each point's reality cone extends outward at c. Light moving faster than that could be used to change the flow of time by monkeying up causality.

rwald
12th March 2003, 08:19 PM
Moving really fast?

It's true; some light can
Move superluminally.

As for special rel:
It's not affected by this.
I do not get why.

BillyJoe
13th March 2003, 02:05 AM
Seems to me, rwald,
It's all just a clever trick.
The explanation?.....

We have a light pulse
Composed of several waves.
Each travels at c.

The summation wave
Seems to travel above c
And here's how it's done:

Pulse passes through gas
- Laser-soaked cesium gas -
(If you need to know).

The component waves
Rephase as they pass through it.
And then they summate.

But the rephasing
Causes the summation wave
To appear early.

So it only seems
To travel above light speed.
Seems to me at least.

garys_2k
13th March 2003, 08:21 AM
You've got it, BJ.
Rephasing takes place closer
Than it would if no air

Existed between
The pulse's starting point, and
Where they do with gas.

It is not really
Faster than light travel, no,

Change in location
Of where the pulses rephase;
Thank you very much.

I really suck at Haiku.
I'll leave it for you.

Kiri
13th March 2003, 08:53 AM
Hawking is so smart
I cannot understand him.
This is much better.

scribble
13th March 2003, 10:30 AM
Incredible geeks
have way too much free time but
i quite enjoyed it

rwald
13th March 2003, 06:06 PM
You're right, BillyJoe;
It's not really FTL.
It just "looks" like it.

Actually, when I
Heard of these experiments,
I didn't get them.

I saw that people
Who know far more than I do
Said it minds Einstein.

I guess that I will
Have to take your word for it.
If it's true, you'd know.

arcticpenguin
11th July 2003, 06:36 AM
bump

rhyme by popular request.
I am quite ashamed.

Samus
11th July 2003, 06:40 AM
Originally posted by arcticpenguin
bump
I'm disappointed that he
Didn't use haiku

BillyJoe
11th July 2003, 07:35 AM
ar tic pen gu in
did not use hai ku, god damn

:cool:

Ziggurat
11th July 2003, 12:49 PM
Originally posted by rwald
Relativity.
First, there's "special;" it
Has no acceleration

This is a common
misunderstanding many
people often have

special rel. really
can do acceleration
though it's not easy

Problems arrise not
from acceleration, but
only from gravity

rwald
11th July 2003, 02:04 PM
However, if I
Understand general rel,
They are both the same.

Acceleration
And gravity, that is; they
Can't be distinguished.

no one in particular
11th July 2003, 02:14 PM
I agree, rwald.
Perhaps I could be wrong though.
That is what I thought.

Ziggurat
11th July 2003, 07:13 PM
gravity is like
acceleration if it
is uniform, but

Gravity is not
globally uniform, so
to deal with that fact

we use general
relativity, which can
explain curv'd space-time

Ziggurat
11th July 2003, 07:24 PM
Ah, hell with it. I can't keep up this Haiku stuff. But here's the skinny:

1) special relativity can handle acceleration.
2) uniform gravity is just like acceleration.

One might come to the conclusion that special relativity should therefore be able to handle gravity. But it can't. Why? Well, consider two people on the opposite sides of the earth. Special relativity would need to treat both of them like they're accelerating away from each other, but they're clearly not. The problem is that the caveat of the gravitational field being uniform clearly doesn't hold here.

What general relativity does is use the concept that uniform gravity is just like acceleration in order to some up with a theory (really a GEOMETRY) to explain space-time.

People always obsess about this idea that gravity is just like acceleration, but I think the better way of looking at it is that any freefall is an inertial reference frame, that is, a free-falling object is NOT accelerating. In order for that to make sense, you need a curved space-time, so that "straight" (unaccelerating) trajectories through space-time looked curved to our naive Euclidean ideas of space.

So special relativity can handle acceleration. But only in a flat space-time. Once you throw in curvature from gravity, it becomes insufficient.

rwald
11th July 2003, 10:15 PM
OK, let me see
If I understand what you
Are trying to say:

Special rel works with
Constant acceleration;
Nothing more than that.

Gravity's not like
Constant acceleration;
It's like it changes.

So, gravity and
Changing acceleration
Need general rel.

I guess that makes sense.
Though I don't get why special
Can do constant a.

Six Not So Easy Pieces
By Richard Feynman.

I have started it,
But the math got difficult.
I must persevere.

BillyJoe
11th July 2003, 11:56 PM
Special rel and a:

rwald
12th July 2003, 12:22 AM
Thank you, BillyJoe.
That site was informative.
Let me try again:

Special rel always
Assumes that space-time is flat.
This is the difference.

Using special rel,
Acceleration is said
To be absolute.

It's relative; not so with
Acceleration.

However, when you
Use general rel, all is
Fully relative.

That's because space-time
Contorts with gravity and
Acceleration.

You can't say whether
You are accelerating,
Or on a planet.

Special rel lets you
Know acceleration; in
General you can't.

(I hope that last verse
makes sense to most; it's not one
Hundred percent clear.)

Anyway, I hope
This clears up any problems.

PygmyPlaidGiraffe
26th July 2003, 02:13 PM
In case any one missed it

Question posed in a chat room:

if you spin a sphere really fast can you create a gravity well that you can push?

my response:

tough question.... have to consider how relativilty applies
the spinning sphere would warp space /time as its spin accelerates

Angreifen's response> yes it is krate... but if you can do so you could probably create a new propulsion system

me: for a propulsion system the gravity well can not be formed around the vessel and expect it to move... the well would have to be formed ahead of the vessel

I am having some trouble wrapping my mind around this ....

BillyJoe
27th July 2003, 03:11 AM
I think you might be right PPG, but for a definitive answer perhaps you'll need to direct some of the physicists on the board (such as Stimpson C Cat or Tez) to this thread.