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# Edge of the Universe

Bones-O

1
Tue 26 May, 2009 11:40 am
@Krumple,
Krumple wrote:
Yes, but why does everyone keep ignoring the fact that time adds upon itself? Microseconds would go on to become seconds, then minutes, then hours then days, so on and so forth.

For ~ a year at that altitude I was estimating. Sure, if you stay at the top of a tower for long enough you'll see a noticeable lag. A year isn't going to do it.

Krumple wrote:

In the first instance you have a total of 20 micro seconds.

In the second instance you have a total of 10 micro seconds.

This is a constant for altitude right? So as you continue with time the micro seconds would add upon themselves accordingly. This is what people neglect with the math.

Uh... no, it doesn't work like that. It's not 20 microseconds at bottom of tower = 10 microseconds at top. For a simple, perfectly spherical system, it's more like:

t = t0 SQRT(1 - 2GM/rc^2)

t0 is time measured in zero gravity, t is measured at the distance r from the centre of the Earth which has mass M. G and c are constants. So if t1 is time measured at the top and t2 at the bottom of the tower:

t1^2 = t0^2 (1 - 2GM/r1c^2) => t0^2 = (t1^2)/[1 - 2GM/r1c^2]
t2^2 = t0^2 (1 - 2GM/r2c^2) => t0^2 = (t2^2)/[1 - 2GM/r2c^2]

=> (t1^2)/[1 - 2GM/r1c^2] = (t2^2)/[1 - 2GM/r2c^2]
=> t1^2 = t2^2 c^2 r2/r1 ([r1c^2 - 2GM]/[r2c^2 - 2GM])

t2 = 2t1 when t2^2 = 4t1^2, giving:

r1 = r2 [8GM/(3r2c^2 - 2GM)]

G = 6.674 x 10^-11
M = 5.974 x 10^24
c= 3 x 10^8

giving:

r1 = 2.5 x 10^20 r2.

So in the Earth's gravitational field, 1 microsecond at the top will correspond to 2 microseconds at the bottom when the tower is approximately 250 000 000 000 000 000 000 metres high.
0 Replies

Ichthus91

1
Tue 9 Jun, 2009 09:05 am
@Exebeche,
Exebeche;63634 wrote:
All fit together...
I see for example two very precise but completely different myths about the creation of the world in the bible.
Funny how the letters of these myths are totally contradictory.
Maybe the content of these chapters is totally contradictory but at the same time the letters point to precisely the same coordinate in the universe?
Historically it is very well understood that the books of the bible were written at different ages in which people had different opinions about topics like the creation of the world.

Give me the examples and I will give a rational explanation.
0 Replies

Alan McDougall

1
Wed 10 Jun, 2009 12:24 am
@Axis Austin,
A theist to me is simply one who believes in some sort of a divine mind or interllect behind creation and existence.

I don't bow down , sing and pray to what is to me an infinite intellect, I don't proscribe or prescribe to any religious idea of God

It the god of my own finite human understanding and I don't impose my concept of god on anyone else, because what i believe could be absolutely wrong

I do try to listen to others and absorb their truths into myself, but in this i am very selective
0 Replies

boredrightnow

1
Wed 10 Jun, 2009 12:25 pm
@Axis Austin,
I haven't read this whole thread, but the concept of there not being some kind of "physical edge" of a supposedly finite universe has always seemed alien to me.

It's like what else is there? Nothingness? At some point, you'll reach a spot where there is no more space, but my basic knowledge of astronomy seems to say that would be a place neither us, nor any other intelligent race would likely be able to access. Spot, maybe, since one can probably tell if there are no more superclusters in a certain direction. But since things are supposed to get spread out the further you go in space, the probability would be presumably quite low.
Alan McDougall

1
Wed 10 Jun, 2009 09:24 pm
@boredrightnow,
boredrightnow;68057 wrote:
I haven't read this whole thread, but the concept of there not being some kind of "physical edge" of a supposedly finite universe has always seemed alien to me.

It's like what else is there? Nothingness? At some point, you'll reach a spot where there is no more space, but my basic knowledge of astronomy seems to say that would be a place neither us, nor any other intelligent race would likely be able to access. Spot, maybe, since one can probably tell if there are no more superclusters in a certain direction. But since things are supposed to get spread out the further you go in space, the probability would be presumably quite low.

I think the universe does not have an edge it is simply everything in our dimension expanding

It does have an observable edge but in that we only see the past by looking at quasars
Holiday20310401

1
Thu 11 Jun, 2009 04:01 pm
@Alan McDougall,
I have wondered, if you were to take a 4D shape and say you could hold it in your imaginary 4D hand, and then you squished it but the shape retained the same volume. (Let's pretend this 4D shape is the universe) If we altered our perception to 3D and placed ourselves inside the shape, what would we observe?

But I also think the 'closedness' of the universe is dealing with something a matter-like analogy doesn't deserve to describe.
Alan McDougall

1
Fri 12 Jun, 2009 04:57 am
@Holiday20310401,
Holiday20310401;68385 wrote:
I have wondered, if you were to take a 4D shape and say you could hold it in your imaginary 4D hand, and then you squished it but the shape retained the same volume. (Let's pretend this 4D shape is the universe) If we altered our perception to 3D and placed ourselves inside the shape, what would we observe?

But I also think the 'closedness' of the universe is dealing with something a matter-like analogy doesn't deserve to describe.

wow!! Holiday a profound thought, think of a two dimensional flatlander trying to rap his mind around a three dimensional object

A balloon to him would start as a minute point , then become a circle and bigger circle until its diameter had entered this two dimensional universe, then the circle will get progressively smaller and smaller until it vanishes from the two dimensional universe

Would the very best Flat Lander Physicist be able too describe exactly what a balloon is to his confused peers?

Your idea is more difficult but many think about other diamentions beyond our universe three
BrightNoon

1
Fri 12 Jun, 2009 06:19 am
@Alan McDougall,
To talk about four dimensional shapes, to say that there may be 'other dimensions' is simply meaningless. What is a 4D shape? If we can't define it, saying it might exist means nothing. The universe might contain shubbaflubbers. I guess it might, but what's a shubbaflubber?
TurboLung

1
Fri 12 Jun, 2009 08:38 am
@Kreist,
Kreist;47169 wrote:
if the universe is infinitely large, there is an infinite chance of an infinite number of possibilities happening, which would mean there are infinite copies of you an i out there.

that means that there is the infinite chance that there are also no copies of ourselves. is it possible to have copies of ourselves out there, but at the same time NO copies of us out there? maybe the 4th dimension allows this infinite possibility.
0 Replies

xris

1
Fri 12 Jun, 2009 12:33 pm
@BrightNoon,
BrightNoon;68516 wrote:
To talk about four dimensional shapes, to say that there may be 'other dimensions' is simply meaningless. What is a 4D shape? If we can't define it, saying it might exist means nothing. The universe might contain shubbaflubbers. I guess it might, but what's a shubbaflubber?
A shubbaflumber is a strange exotic fish of the lower Nile,it has the ability to use a water snorkel type device on its gills.It can be seen floating on the surface while it snorkel type device is lowered into the water.It allows it to observe our world while breathing through its gills.Jacque Cousteau i have heard designed his subaqua equipment after eating one in a Cairo restaurant.
Alan McDougall

1
Fri 12 Jun, 2009 08:35 pm
@xris,
xris;68592 wrote:
A shubbaflumber is a strange exotic fish of the lower Nile,it has the ability to use a water snorkel type device on its gills.It can be seen floating on the surface while it snorkel type device is lowered into the water.It allows it to observe our world while breathing through its gills.Jacque Cousteau i have heard designed his subaqua equipment after eating one in a Cairo restaurant.

XRIS you are killing me really killing me :bigsmile:
0 Replies

Neil D

1
Mon 15 Jun, 2009 07:34 pm
@xris,
Einstein was the one who said gravity was not a force, but was caused by matter warping space. Seems like it is still considered one of the four fundamental forces of nature although.

Gravity didnt seem to work well in the standard model for quantum mechanics, but seemed to be required in string theory...which is now M Theory.

As far as i know now, time is affected by gravity..the stronger the gravitational pull, the slower time moves.

There is also a theoretical partical called a graviton.
xris

1
Tue 16 Jun, 2009 08:15 am
@Neil D,
Neil;69518 wrote:
Einstein was the one who said gravity was not a force, but was caused by matter warping space. Seems like it is still considered one of the four fundamental forces of nature although.

Gravity didnt seem to work well in the standard model for quantum mechanics, but seemed to be required in string theory...which is now M Theory.

As far as i know now, time is affected by gravity..the stronger the gravitational pull, the slower time moves.

There is also a theoretical partical called a graviton.
So why is gravity so weak?Why does it only attract not repel?
Alan McDougall

1
Wed 17 Jun, 2009 12:28 am
@xris,
xris;69596 wrote:
So why is gravity so weak?Why does it only attract not repel?

Gravity is locally weak, but together with all matter in the universe it is the most colossal force in the universe, with the exception of your clever remark. "what repels it.?"

Something that repels all the matter in the universe must be greater than gravity?

If the singularity that started the universe was infinitely massive how could it be propelled outward to create the universe

The Large Hadron Collider in Switzerland hope to find the Higgs particle or god particle which might explain your short and profound question, Anti gravity , the strange force that is propelling our universe indeed accelerating it outward into infinity

Why is the universe asymmetrical instead of what it should have been symmetrical? Matter and Antimatter should have cancelled each other out in an unimaginably huge explosion leaving the universe just a hot soup of Gamma rays

Peace
0 Replies

Neil D

1
Wed 17 Jun, 2009 02:23 pm
@xris,
xris;69596 wrote:
So why is gravity so weak?Why does it only attract not repel?

I believe the reason they are saying now as to why gravity is such a weak force as compared to the other three, is that it is everywhere and not just confined to within the Brane(boundary), of our universe. In a multiverse, gravity would permeate every universe and exist everywhere in the Bulk(all space that is not a universe). This gave me the crazy idea that gravity may be some kind of Godfield, since it is everywhere.

As to why it doesnt repel. Well, i think Einstein may say something like....Gravity warps the spacetime fabric, and objects simply take the path of least resistance around this warping, of course he would have said it much better.

The M Theorists may say it has something to do with the graviton.

Some different theories going on here, and im no physicist, so my explanations are somewhat vague.
validity

1
Wed 17 Jun, 2009 11:02 pm
@Neil D,
Gravity is weak compared to what? Other forces? It could be that gravity is not a force and as such should not be compared to as though it was.
0 Replies

Alan McDougall

1
Thu 18 Jun, 2009 02:57 am
@Axis Austin,
The universe really does not have an edge it has an "observable horizon" which is being pushed back further and further as the power of our telescopes increase
0 Replies

TurboLung

1
Thu 18 Jun, 2009 04:26 am
@xris,
xris;69596 wrote:
So why is gravity so weak?Why does it only attract not repel?

of the four forces, gravitiy is the weekest. gravity in effect isn't a force as most would think. it is the bending of space and time.

imagine a bowling ball sitting still on a trampoline. the bowling ball we can pretend is the earth. as you can imagine, the trampoline warps around the bowling ball. at the edge of the material of the trampoline is where the moon would be, constantly circling the edge, unable to escape. of course, we have to imagine the trampoline [time/space] warping in more than 3-dimensions.

in effect, gravity is really velocity. einstein realised all this about gravity one day at work when he realised that a man falling does not feel his own weight.

i believe the biggest experiment being conducted in the world's largest particle collider [europe] is to smash particles together and look for a smaller particle called a graviton [?]. this is believed to be the cause of gravity as we know it.
Alan McDougall

1
Thu 18 Jun, 2009 06:52 am
@TurboLung,
[QUOTE=TurboLung;70047]of the four forces, gravitiy is the weekest. gravity in effect isn't a force as most would think. it is the bending of space and time.

imagine a bowling ball sitting still on a trampoline. the bowling ball we can pretend is the earth. as you can imagine, the trampoline warps around the bowling ball. at the edge of the material of the trampoline is where the moon would be, constantly circling the edge, unable to escape. of course, we have to imagine the trampoline [time/space] warping in more than 3-dimensions.

in effect, gravity is really velocity. einstein realised all this about gravity one day at work when he realised that a man falling does not feel his own weight.

i believe the biggest experiment being conducted in the world's largest particle collider [europe] is to smash particles together and look for a smaller particle called a graviton [?]. this is believed to be the cause of gravity as we know it.[/QUOTE]

Explain that in the light of a lead ball falling from a high tree onto the ground below? Much of what we say is correct gravity does bend space and effect time, but only in colossal gravity fields like the a planet, sun or black hole etc.

This was proved during the eclipse of the sun in 1919 when the planet mercury could be seen, when it should have been hidden behind the sun. The fabric of space bent around the sun making Mercury visible
[CENTER]
[/CENTER]
[CENTER]
[/CENTER]

Neutron star 189610000000 Black hole infinite
100000000000000000000000
As you see here, you will weigh different on other objects across our milky way galaxy. You will also weigh different on other objects across the entire universe. This is because if you stood on the surfaces of these objects, you will feel more or less gravity. Maybe on just some objects in the universe, you will experience the same gravity as earth, our home planet.
[CENTER]
[/CENTER]
As you see here, we have earth and other objects that have more gravity. The white line represents the fabric of space-time. The more gravity, the more it gets bent, the more you will weigh.

Bracewell

1
Thu 18 Jun, 2009 09:06 am
@Alan McDougall,
Even if the Graviton is found I don't think it will help much as it will have to be a very smart particle indeed.
0 Replies

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