How fast can we go?

astro_uk · Post by **astro_uk** » Tue Jan 23, 2007 3:15 pm

There is no evidence to indicate expansion of the universe. Although we know that parts do expand and some parts contract.

So which is it? No evidence of expansion, or expansion and contraction?

Of course there is plenty of evidence for expansion but I can't be bothered to repost it for the umpteenth time.

orin stepanek · Post by **orin stepanek** » Tue Jan 23, 2007 3:17 pm

Going back to how fast we can go! I wonder just how far mortal man can travel in space. Just because we may not age at the speed of light; We may never really go that fast; not with present technology. The energy needed to go that fast would be trememdous.

http://math.ucr.edu/home/baez/physics/R ... ocket.html
Orin

harry · Post by **harry** » Wed Jan 24, 2007 9:50 am

Hello All

Hello Orin

Sorry if it looks like that I argue, i do not mean to.

Anyway
Re:http://www.wonderquest.com/ExpandingUniverse.htm

I understand where the writer is coming from. He assumes the Big Bang Theory is correct and proceeds to work along those lines.

Ok read these links

Edwin Hubble...
and the myth that he discovered an expanding universe
http://home.pacbell.net/skeptica/edwinhubble.html

Evidence for a Non-Expanding Universe: Surface Brightness Data From HUDF
http://arxiv.org/abs/astro-ph/0509611

A Bang into Nowhere
Comments on the
Universe Expansion Theory
http://redshift.vif.com/JournalFiles/V1 ... 0N1ANT.pdf

The Sunyaev-Zel'dovich effect in a sample of 31 clusters - a comparison between the X-ray predicted and WMAP observed CMB temperature decrement
http://arxiv.org/abs/astro-ph/0510160

The Hubble diagram extended to z>>1: the gamma-ray properties of GRBs confirm the Lambda-CDM model
http://www.arxiv.org/abs/astro-ph?papernum=.+0605430

Cosmic Matter and the Nonexpanding Universe.
http://www.newtonphysics.on.ca/UNIVERSE/Universe.html

The issue is this:

Why should the universe expand?
What are the forces that would make it expand?

=====================================

When I spoke of parts of the universe expanding and contracting.

We see this in the formation of a galaxies.

We notice it contracting when objects are sucked into a black hole.

We notice supernova and the resulant Nebulae expanding for many light years.

We notice compact star cores from contraction
=======================================

Again Orin, I'm very sorry if you think I'm out to argue for the sake of it.

orin stepanek · Post by **orin stepanek** » Wed Jan 24, 2007 3:17 pm

It is true that I assume an expanding universe because you hear so much about it what with the red shift and all. We as humans will probably debate this issue until there is an accurate way to measure this that everybody is content with.

I really don't know if that is possible. not any time soon anyway. Harry I appreciate your point of view along with everyone else's as all the knowledge we know of the universe has grown so rapidly in the last few years that there are so many theories that will take a long time to sort out.

I for one do believe that the age of the universe is finite. But; as to the size, I believe it is infinite. We will never know as we can only see as far as the age of the universe. Wouldn't it be great if we could see beyond the speed of light.

If we could travel at the speed of light how many stellar systems do you think man might eventually be able to visit?

Orin

harry · Post by **harry** » Thu Jan 25, 2007 1:55 am

Hello Orin

If it is possible to travel at the speed of light, and our body can withstand the what ever, than it would take thousands of years, 25 thousand to reach the centre 25 thousand to reach the ext part of the MW. Four yrs just to reach the nearest star.

But! if we could travel much much faster than we may have a chance at seeing a few stars. Just dreaming.

Many of the theories should be resolved in the near future. There is alot of scientists out there who are not happy with what has happened in the past particularly with ad hoc ideas supporting some theories and the churches and governments influencing outcomes.

Redshift is out in the open and under dispute.

As for the Big Bang, people should research for themselves, I do not want broken windows by emotional bangers.

cosmo_uk · Post by **cosmo_uk** » Thu Jan 25, 2007 10:49 am

Not true Harry, Due to Special Relativity if it was possible to travel arbitrarily close to the speed of light you could pretty much reach anywhere in an arbitrary amount of time. So there is no need to travel faster than light.

length contraction

L=Lo/y

Lo=proper length in object's rest frame (distance to star)
L=distance to star observed by spacesip travelling at speed v parallel to Lo

y=lorentz factor= 1/(1-(v^2/c^2))^0.5
c=speed of light

so if y is massive as v~c then the length is contracted so small that it wouldn't take long to go the distance at c.

see also time dilation

so pick a value you would like L to be or how long you would like to take to reach anywhere in the universe and you'll find a value of v thats below c that will fullfil your needs.

Orca · Post by **Orca** » Thu Jan 25, 2007 12:21 pm

Astro, isn't that the same effect that explains why if two galaxies are traveling away from each other at say, .7 c...the rate at which the two galaxies fly apart is still less than c...that is, not 1.4 c?

orin stepanek · Post by **orin stepanek** » Thu Jan 25, 2007 2:07 pm

Ahh! and if your traveling away from Earth at c and your 3 light years out and you send a message to Earth; would that message ever reach Earth? Or; would it stay 3 L Y away?

Orin

BMAONE23 · Post by **BMAONE23** » Thu Jan 25, 2007 2:07 pm

When we look at the Hubble Ultra Deep Field http://imgsrc.hubblesite.org/hu/db/2004 ... /print.jpg,
some of the galaxies are oddly shaped http://imgsrc.hubblesite.org/hu/db/2004 ... ll_jpg.jpg
while others are larger and fairly well formed http://imgsrc.hubblesite.org/hu/db/2004 ... ll_jpg.jpg
We tend to think along the lines of size = distance, the farther away from us something is, the smaller it will appear to be. If this is the case, then the larger galaxies are closer to us and the smaller galaxies are farther away from us (or farther back in time lightwise). If the expansion is indeed happening then all galaxies at the same distance from us should exhibit the same red shift value as expansion occurs. Is this the case??? Are there any of the smaller (younger, more distant galaxies) that display a BLUE shift indicating they are moving towards us? Or are they just red shifted to a lesser degree if they are moving in our direction but being forced away from expansion?

astro_uk · Post by **astro_uk** » Thu Jan 25, 2007 9:26 pm

First off Orca, that was Cosmo, I'll leave it them to explain.

Orin, not sure, seeing as you can only actually travel at c if you are massless there is actually no mechanism whereby you could send a signal back if you were travelling at c, so I think the answer may be according to the rules its impossible. I guess that the real answer is that if you use the relativistic doppler equation

1 + z = (1 +(v/c)) / SQRT(1 - (v^2/c^2))

as you approach c the redshift becomes infinite, so the signal becomes so redshifted that you couldn't detect it.

To answer BMAONE23's question, there are no know galaxies with blueshifts outside of the immediate vicinity of the MW, well within about 10Mpc anyway.
All galaxies have some random motion superimposed upon the actual expansion, this random motion (perculiar velocity) is due to them being attracted to other nearby concentrations of mass, like galaxies or clusters of galaxies. These velocities are generally less than a few 1000kms, so for the Hubble Law to be accurate you really need to look out far enough that the perculiar velocities are of the order of 10% of the expansion velocity. So if you look at the individual velocities of galaxies in a distant cluster, they all scatter around some mean, the mean being the hubble expansion value for the cluster, the differences between the galaxies are due to their own perculiar orbits within the cluster.

harry · Post by **harry** » Thu Jan 25, 2007 10:18 pm

Hello all

Cosmo said

Not true Harry, Due to Special Relativity if it was possible to travel arbitrarily close to the speed of light you could pretty much reach anywhere in an arbitrary amount of time. So there is no need to travel faster than light.

I think you are mistaken.

If you have a distance of 100 Light Years
Travelling at C
IT will take you 100yrs.

cosmo_uk · Post by **cosmo_uk** » Thu Jan 25, 2007 10:53 pm

No Harry, you need to think in terms of special relativity here which is not intuitive. As far as we're concerned light takes a year to travel one light year. However if we were sat on the photon being emitted we would arrive instantaneously at our destination wherever that might be due to length contraction. it all depends on your frame of reference. stick v=c into the equation above and you'll get an infinite value for y. therefore L=0.

Of course its not possible to travel at c if you have mass but hey!

harry · Post by **harry** » Fri Jan 26, 2007 1:41 am

Hello Cosmo

I do understand relativity.

You can use maths to do what ever you want. I wish It could so, Mr Scotty make it so,,,,,,,,,,,,,,,I think its from Star Trek

Reality is that:

It cannot be done.

orin stepanek · Post by **orin stepanek** » Fri Jan 26, 2007 2:02 am

OK so it's impossible to move mass at c. Hypothetically going at c you couldn't communicate outside your spaceship. And if a warp drive could move your ship at faster than light speed by contracting and compressing space you would actually go slower [inside your craft of course] than you would moving mass at c. However; for the folks at home you would return sooner and there would be less of an aging difference because time in the warp bubble would be normal. Hypothetically speaking? Still you would be unable to communicate with anyone outside your space ship.

So probably There will be no real Star Trek for a long long time.

Orin

harry · Post by **harry** » Fri Jan 26, 2007 2:36 am

Hello All

This ageing thing going at the speed of light is not correct.

Time is a word that cannot change what ever speed you do.

But! the means of comminication changes and therfore you have a delay in communication but not a change in actual TIME or a physical change.

Time Dilation and Twin Paradox Debunked
http://www.physicsmyths.org.uk/timedilation.htm

Propagation Speed of Gravity and the Relativistic Time Delay
http://arxiv.org/abs/astro-ph/0301145

Can I communicate faster than light?
http://curious.astro.cornell.edu/questi ... number=592

I am driving my car at the speed of light and I turn on my headlights. What do I see?
http://math.ucr.edu/home/baez/physics/R ... ights.html

Sorry if I posted too many links.

If you do not like links than do not open them.

Orca · Post by **Orca** » Fri Jan 26, 2007 3:09 am

astro_uk wrote:First off Orca, that was Cosmo, I'll leave it them to explain.

Astro, Cosmo...one of yous guys...

harry wrote:Time is a word that cannot change what ever speed you do.

It's been proven over and over. Time is relative; it's slowed down by both mass and speed.

Which makes perfect sense...since an object gains energy when it increases velocity...therefore it gains mass, because of E=mc^2...and if it gains mass time slows down, relative to outside observers.

Look at atomic clocks in orbit vs the surface of the planet...or even at different elevations.

Look at sub-atomic particles that are accelerated to significant portions of the speed of light...there are quantifiable increases mass AND half-life.

In fact, the electrons firing at the screen you're looking at (assuming you are using a CRT monitor of course) are 4% heavier than the electrons in the keyboard you are typing on. Why? Because of their speed.

Harry, I think it's ironic to hear you make 'Trek' jokes about mainstream science...

Just joshin' ya buddy... 8)

orin stepanek · Post by **orin stepanek** » Fri Jan 26, 2007 3:33 am

Hi Harry! I have trouble understanding how time can be different for things moving at different speeds also. Even though relativity tells us so!But hey; I'm willing to learn. Thanks everybody for all your input. How can we measure that a photon that takes 8 minutes to travel 93 million miles can not age at all? And how do we know that is true?

Orin

harry · Post by **harry** » Fri Jan 26, 2007 3:43 am

Hello Orin

When we talk in relative terms that you time difference occurs.

The actual time never changes regarless if you are in the middle of a black hole at the event horizin or 100 billion light years away.

Actual time does not change for nobody.

Actual Time cannot contract or expand.

Recorded time can expand and contract depanding on the speed of the person moving away or coming towards.

Read some of the above links.

cosmo_uk · Post by **cosmo_uk** » Fri Jan 26, 2007 12:14 pm

harry:

You can use maths to do what ever you want

Am I right in thinking you don't believe in relativity????

Oh dear!

Orca · Post by **Orca** » Fri Jan 26, 2007 12:59 pm

Harry, lets look at the Twin Paradox link.

From what I read, the author simply has a different interpretation of the physical behavior of moving objects than described in relativity.

I'd also be willing to wager that the author has no physical experiment to prove his point. If he did, he'd get funding, then he'd test his theory; if it was correct, other physicists around the globe would repeat the experiments. Then, if all was green, he'd be sitting at his desk admiring his Noble Prize while modern physics collapsed around us and we began the 21st century by "going back to the drawing board."

But thus far, it's just one physicist's interpretation. That's it. That's all it is until proven by experiment.

I think it's great that you continually question current theory. Theories should be tested again and again. But when you support a new theory, it has to be based on experiment and scientific method.

ckam · Post by **ckam** » Fri Jan 26, 2007 1:26 pm

cosmo_uk wrote:harry:
You can use maths to do what ever you want
Am I right in thinking you don't believe in relativity????

Oh dear!

harry does not believe in almost anything.

Orca · Post by **Orca** » Fri Jan 26, 2007 10:14 pm

ckam wrote:
cosmo_uk wrote:harry:
You can use maths to do what ever you want
Am I right in thinking you don't believe in relativity????

Oh dear!
harry does not believe in almost anything.

He believes Big Bang theory is wrong...and it's a belief alright...because the theory has not been dispelled scientifically.

harry · Post by **harry** » Sat Jan 27, 2007 3:15 am

Hello All

I understand relativity I do not allow my emotions to rule.

There is nothing wrong with relativity, it's how people look at it.

The Big Bang theory has been hit on the head by hundreds of scientists.

God only knows why its still being thought as the standard theory.

In due time some one is going to be eating their hut.

Smile,,,,,,,,,,,,,,,I hope its not me.

Until than respect each other.

Show me where I'm wrong don't just say so!

orin stepanek · Post by **orin stepanek** » Mon Feb 05, 2007 11:38 pm

http://www.indiadaily.com/editorial/3582.asp

http://www.indiadaily.com/editorial/3244.asp

http://www.totse.com/en/technology/spac ... travl.html

If someday bending of space can be achieved; man will have opportunities to live among all that there is? Seems that we can do this only in our dreams.

I almost wish I were a boy again.
Orin

ckam · Post by **ckam** » Tue Feb 06, 2007 7:09 am

will you people ever stop chewing same gum over and over and over?