If I could travel at the speed of light - Page 3

pmrid (Peter) · #41 22-09-2011, 10:33 PM

Quote:

Originally Posted by sjastro

The derivation of the formula is simple, straightforward and logical.

Regards

Steven

I have no problem working the problem and see how it produces the result "c". But it is still keeping me awake.
If, instead of my travelling at c, I am accelerating towards c. As I continue to accelerate and reach high velocities, my approach velocity reduces as the effect of that formula kicks in????
Peter

renormalised (Carl) · #42 22-09-2011, 11:18 PM

Quote:

Originally Posted by leonie-macaroni

Are you implying that if static, they remain massless? Or differ in mass?

Where can I learn more about particle physics?

I'm getting a bit lost, but this is all so interesting.

They're massless in all cases, whether they're at rest or moving. The only bosons that have mass are the W and Z bosons. This is because they gain mass via their interaction with the Higgs field.

However, hold the announcement for the present....the Higgs mechanism might not yet exist, if they don't end up finding the Higgs boson itself.

Just look up special and general relativity, higgs boson, higgs mechanism, quantum mechanics and such on wikipedia. That will give you a brief intro of the subjects in question. If you want books about these subjects, let me know and I'll see what I can find that you'll be able to follow without having to go get a degree

leonie-macaroni (Leonie) · #43 23-09-2011, 02:58 AM

Thanks Carl!

Expect questions from me in the future!

sjastro · #44 23-09-2011, 08:43 AM

Quote:

Originally Posted by pmrid

I have no problem working the problem and see how it produces the result "c". But it is still keeping me awake.
If, instead of my travelling at c, I am accelerating towards c. As I continue to accelerate and reach high velocities, my approach velocity reduces as the effect of that formula kicks in????
Peter

To understand things that accelerate, special relativity is no longer relevant and one needs to look at general relativity instead.

If we accelerate up to a particular velocity and stay at that velocity, the formula is applicable where the velocity is constant.

The formula is applicable for all constant velocities, it's just the effects of the formula are not observable at slower velocities.

If you look at the formula there is a (v/c)^2 term. For an object travelling at 100 km/hr, the (v/c)^2 term equals 3.21 X 10^-11 which being a very small number for all intents and purposes equals zero.
For small velocities we can take the (v/c)^2 as equalling zero, then our formula reduces to the familiar approach velocity 2v.

If the object is travelling at say 0.9c the effects of the formula are much more noticeable. The (v/c)^2 term is now equal to 0.81. At 0.9999c (the speed of protons at the LHC) it becomes 0.9998.

So as you travel at higher constant velocities the effects become increasingly apparent.

Regards

Steven

glenc (Glen) · #45 23-09-2011, 09:29 AM

How long does light take to reach us from various objects?
At the speed of light (9,461,000,000,000 km per year) it takes light:

1.3 seconds to reach us from the Moon
8.3 minutes to reach us from the nearest star, the Sun
4 hours to reach us from Neptune, the Sun’s outermost planet
4.3 years to reach us from Alpha Centauri, the nearest star, apart from the Sun
370 years to reach us from the bright open star cluster Pleiades (M45)
710 years to reach us from the Helix planetary nebula, a dying star (NGC7293)
1,350 years to reach us from the Orion Nebula (M42)
15,800 years to reach us from the globular star cluster Omega Centauri (NGC5139)
25,900 years to reach us from the black hole in the middle of our Milky Way galaxy (Sgr A*)
157,000 years to reach us from the small local galaxy the Large Magellanic Cloud (LMC)
2,540,000 years to reach us from the large local galaxy in Andromeda (M31)
2,400 million years to reach us from the bright magnitude 12.9 quasar 3C 273

renormalised (Carl) · #46 23-09-2011, 10:04 AM

And 42.5 billion years from the observable edge of the Universe

Mliss (Mel) · #47 23-09-2011, 11:51 AM

http://www.bbc.co.uk/news/science-environment-15017484

thought this may be of interest

renormalised (Carl) · #48 23-09-2011, 12:43 PM

Quote:

Originally Posted by Mliss

http://www.bbc.co.uk/news/science-environment-15017484

thought this may be of interest

Already in the Science Forum

Paduan (Brett) · #49 29-09-2011, 12:03 AM

the formula is sound however advanced mathematics is like a poll you can get it to reflect the view of the individual balancing the equations. i am not intending to call anybody a liar but this previous statement was proven to me by my mathematics teacher in yr 10 where he proved using calculus that 1 can equal 0. now we all know that to be false yet mathematically it is possible. Einstein was a genius who told the world that "c" was the ultimate velocity of matter, yet just the other day nutrinos were accelerated faster than light. however mathematically it is impossible.
Physics and mathematics are like a beautiful object, held with great stead the eye of the beholder!

Paduan (Brett) · #50 29-09-2011, 12:20 AM

before anyone points it out yes i know that it is a problem with the math i was just using it as an example. 1 cannot equal 0 yet to the uninitiated it seems true which was my point. and i agree with you Peter i believe that the resultant distance is 3ly however neither particle exceeded "c"

sjastro · #51 29-09-2011, 08:17 AM

Quote:

Originally Posted by Paduan

the formula is sound however advanced mathematics is like a poll you can get it to reflect the view of the individual balancing the equations. i am not intending to call anybody a liar but this previous statement was proven to me by my mathematics teacher in yr 10 where he proved using calculus that 1 can equal 0. now we all know that to be false yet mathematically it is possible. Einstein was a genius who told the world that "c" was the ultimate velocity of matter, yet just the other day nutrinos were accelerated faster than light. however mathematically it is impossible.
Physics and mathematics are like a beautiful object, held with great stead the eye of the beholder!

You are way off base.
This is the sort of comment made by people who do not understand mathematics.
Using calculus to prove that 1=0 either indicates that your teacher was pulling your leg or is a mug who shouldn't be teaching mathematics.

On the subject of neutrinos travelling faster than light is still pending investigation, many scientists are of the opinion that the experiment is flawed.

Regards

Steven

Poita (Peter) · #52 29-09-2011, 09:17 AM

Are you referring to:
Let x = 0
.. x(x - 1) = 0
.. x - 1 = 0
.. x = 1
.. 1= 0

Hidden divisions by zero are often used as a trick to catch the unwary, the above uses that cheat, and so is invalid.
Your teacher was probably proposing it, hoping you would find the hole in the 'proof'.
There is another similar 'proof' that 1 = 0 using the indefinite integral that has a similar hidden division by zero, but also looks at first glance to be correct.

Paduan (Brett) · #53 29-09-2011, 09:38 AM

if you notice i replied to my own post. i do know that it is flawed and maybe it was a bad example but history is full of mathematical indescrepancy which is the point i was trying to make. as for the nutrino's they do not have Einstein telling them that they are moving too fast. as i remarked in a previous post. It was not too long ago we (the human race) believed that the speed of sound was an impenetrable BARRIER

sjastro · #54 29-09-2011, 10:28 AM

Quote:

Originally Posted by Paduan

if you notice i replied to my own post. i do know that it is flawed and maybe it was a bad example but history is full of mathematical indescrepancy which is the point i was trying to make. as for the nutrino's they do not have Einstein telling them that they are moving too fast. as i remarked in a previous post. It was not too long ago we (the human race) believed that the speed of sound was an impenetrable BARRIER

The argument that one uses "history" as a case to establish flaws in mathematics pertaining to current theories is a logical fallacy.

In fact if you use history as a guideline you will find that most theories fall by the wayside as observations or experiments do not match up with the predictions made by the theory. Very rarely are theories rejected because of any discrepancies in the maths. The application of the maths may be wrong but the actual maths itself isn't wrong.

When did Einstein say things couldn't travel faster than light?
What Einstein specifically stated was that objects in space cannot exceed the speed of light.
Expanding space itself can exceed the speed of light as is found with the recession velocities of distant galaxies.

Finally the areodynamic speed of sound barrier was not considered a theoretical barrier that could not exceeded.

Regards

Steven

renormalised (Carl) · #55 29-09-2011, 11:42 AM

That's the big problem....everyone has been laboured under the impression that Einstein said nothing can travel faster than light, period. No matter what the situation and that has been a thorn in the side of physics (especially in the public conscience of the field) for many years. You even hear scientists proclaim it loud and clear for all to hear. But as Steven has mentioned, that's not what Einstein actually said. It's about time people learn about it and stop parroting everyone else before them.

Poita (Peter) · #56 29-09-2011, 12:17 PM

I found this a fun read:
http://www.weburbia.com/physics/FTL.html

Brian W (Brian) · #57 29-09-2011, 02:08 PM

Finally the areodynamic speed of sound barrier was not considered a theoretical barrier that could not exceeded.

Regards

Steven[/QUOTE]

Steven not to hijack the thread but could you expand a bit on the above. You have emphasized 'theoretical' and that to me means you are using the word pointedly.

However, as I understand the history... the whole point of the American program was to find out if it was possible to break the sound barrier. they thought they could but they did not know they could.

As no one knew the answer and the whole program was developed to find the answer it seems to me that they had a theory and they tested it?

brian

Poita (Peter) · #58 29-09-2011, 02:46 PM

The program wasn't to see if the sound barrier could be broken, it was already known that many items broke it, the program was setup to see if a controlled vehicle (e.g. a piloted jet) could break the barrier and maintain control.
The aim was to be able to make fighters/bombers etc. that could fly supersonically, not whether the barrier could be broken at all, that was already common knowledge.

sjastro · #59 29-09-2011, 03:06 PM

Quote:

Steven not to hijack the thread but could you expand a bit on the above. You have emphasized 'theoretical' and that to me means you are using the word pointedly.

However, as I understand the history... the whole point of the American program was to find out if it was possible to break the sound barrier. they thought they could but they did not know they could.

As no one knew the answer and the whole program was developed to find the answer it seems to me that they had a theory and they tested it?

brian

Brian,

A theoretical barrier is a fundamental barrier imposed by the "laws of nature" and cannot be overcome by technological considerations.

The speed of sound barrier clearly does not fit this definition. Bullets for example could exceed the speed of sound before an aircraft was developed that could do the same.
In this case the speed of sound was a technological barrier that was eventually overcome.

The debate is whether the speed of light is a fundamental barrier or a technological barrier. Based on current observations it would appear to be the former.
Particle accelerators can accelerate protons up to 0.9999c.
There is a law of diminishing returns. As you increase the amount of energy to accelerate protons, the corresponding increase in proton velocity becomes progressively less.
To accelerate protons up to speed c requires the expenditure of an infinite amount of energy.

Regards

Steven

Paduan (Brett) · #60 29-09-2011, 05:06 PM

My statements are being taken far too literal. i am not here to make any body hot under the collar as a few seem to be getting nor am i going to continue the "argument" all i am trying to say is "HAVE AN OPEN MIND". i am not attempting to hassle anybody's intelligence, career path or beliefs.

BY the understanding we have using todays Physics, velocities at "c" and above are impossible. We have come so far in the last hundred years imagine what we will "KNOW" in a hundred years from now