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103 Dec 25, 2011 at 13:38

The worlds gone mad and seems to think that light is relative to the observer… I can think of an example where it couldnt possibly be relative to the observer.

Imagine a robot with a photoelectric metal eye travelling forwards towards a flashed light, and a robot travelling away from the light. If they are both at the exact same place when the light flashes, and the times are measured on the robot eyes, then it COULDNT POSSIBLY BE TRUE that the clock would read the same on both robots, it would be different, because the robot moved a little before the light got to it, and light is relative to the ether, not the observer, which is a complete load of crap.

Someone tell me im wrong…

#### 19 Replies

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101 Dec 25, 2011 at 14:20

There isn’t such thing as ether. Light moves with speed of light (299792458 m/s) for any observer independent of his speed. But it’s true that two robots will see different time of light arrival (and also color will be different).

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103 Dec 25, 2011 at 14:35

The colour being different due to doppler shift, yes… but this isnt the answer I was expecting!
This means you agree with me that its not “relative to the observer”?

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101 Dec 25, 2011 at 18:47

Light IS relative to the observer, but it’s only color, not speed, changing between observers. In your example there is no contradiction: time of flash in each robot’s frame is different. Phrase “they are both at the exact same place when the light flashes” have meaning only relative to some observer. For one robot time of flash is before meeting and for another–after meeting.

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167 Dec 25, 2011 at 23:38

It’s not a “load of horse dung”; it’s an EXTREMELY well-tested theory that’s been validated time and time and time again in a variety of different situations. ;)

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103 Dec 26, 2011 at 07:15

I dont think so, I think the world is stupid.

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151 Dec 26, 2011 at 10:11

Could be that you are right, and the world is stupid.

Or it could be that the theory is right and you just don’t understand the physics involved.

Some of the things that modern science discovers really make my head hurt, like data loss in black holes, (de strange man in the wheel chair, he go crazy boss) :P

I believe in the theory that if anyone really does completely understand the universe, then it will instantly disappear and be replaced with something infinitely more complex :D

6 x 9 = 42 boys

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151 Dec 26, 2011 at 10:31
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141 Dec 26, 2011 at 12:15

Physics change at the speed of light, so what would be impossible at lower speeds, is possible at the speed of light. I think that’s kind of cool myself, although I am just taking people’s word for it since I can’t possibly measure those things. Other things, like the mass of a thing increasing as it approaches the speed of light is just as hard to believe, but they have measured it with particle accelerators. That’s why they have to build those huge things to move tiny particles.

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103 Dec 26, 2011 at 13:03

It still doesnt make sense to me, like I could disprove it, thats why physics never agreed with me…

anyway, just to show you guys i do have a talented mind, have a look at some of my realism in the dark, and you know just because your smart doesnt necessarily mean you agree with all of physics hehe.

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151 Dec 27, 2011 at 10:13

The speed of light is no longer a quaranteed limiting factor.

Two experiments have now confirmed that particles can travel faster than the speed of light. It was quite strange watching the announcements.

One of the labs put out a press release saying “we have these results that show particles can travel faster than light, here is our experiment, what are we doing wrong?”

Then another lab replied saying “Well actually, we have got the same results as well. We didn’t publish them because we thought we would get laughed at”

After that loads of people looked at the experiments and the results and couldn’t find anything they did wrong.

Which is kind of exciting, as it means a lot of our understanding of physics is based on false assumptions and the data we have collected that supports the initial assumptions has to be looked at in a new light.

It’s like null point energy, when I was at school I was told that at absolute zero there is no energy, everything stops. This has now been proved to be wrong, there is some energy. It’s just in a form we don’t understand.

We live in a time when experimental techniques have out paced theoretical physics, in the time of Einstien theoretical physics was far out in front. He came up with amazing, beautiful mathematics to describe things that could only be seen in the mind. I’m amazed how close he came.

Oh and to show what I like to do in my few spare minutes a day, check out these http://forthsalon.appspot.com/

:D

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167 Dec 27, 2011 at 21:14

Stainless, if you’re referring to the OPERA neutrino experiments, it’s very far from accepted that the neutrinos were actually travelling faster than light! Every physicist who has said anything about it lays very long odds against accepting the result at face value, and they are still in the process of analyzing the experiment and the data more closely. This is going to take time and further experiments to resolve; certainly it is not anywhere near “confirmed”.

It’s like null point energy…there is some energy. It’s just in a form we don’t understand.

On the contrary, I would say zero-point energy is understood rather well by real physicists. It is a straightforward consequence of quantum mechanics. Don’t mistake the fictionalized buzzword woo-woo version of zero-point energy for the real thing.

We live in a time when experimental techniques have out paced theoretical physics

Not really. What particle accelerators like the LHC are doing now is testing decades-old predictions from the standard model of particle physics, such as the existence of the HIggs boson. String theory has also been hampered for decades by the lack of any way to experimentally test its predictions. If it were true that experiments were outpacing theory, there would be a lot less excitement when we get results that don’t obviously agree with theory. :)

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151 Dec 28, 2011 at 09:44

:) I really wasn’t thinking about the LHC, I have been more interested in the data coming back from various space experiments, but the LHC is another nice piece of kit that’s throwing up really interesting results.

There are rumours that they have found the Higgs, and rumours that they haven’t but have found something else.

It’s like a soap opera for geeks :D

“Previously on the LHC ….”

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101 Dec 28, 2011 at 21:24

Rouncer, The world is indeed mad. If you think your example of light and speed is confusing, have a look at the classical double slit experiment done with electrons: http://en.wikipedia.org/wiki/Double-slit_experiment#Interference_of_individual_particles

An electron is a discrete particle. When a single electron hits a screen, the position can be seen. (That’s what a CRT TV/monitor does.) Let single electrons pass through a double slit (actually layers of atoms in a crystal), and they will interfere anyway!

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101 Jan 03, 2012 at 18:53

@Stainless

LHC is another nice piece of kit

LHC is a “piece of kit”? That’s like saying the Sistine Chapel is a little bit of paint on some stone. :)

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101 Jan 03, 2012 at 20:39

BTW, light is not relative. That makes no sense. The speed of light is constant. Time “adapts” to maintain this consistency.

Confusion is natural when your framework is incomplete for understanding a complex topic.

You are in New Zeland, right? I am in the US. So, are you on top of the Earth, or am I? Who is haging on for dear life? :)

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151 Jan 03, 2012 at 21:24

we are all hanging on for dear life, we just hang onto a different framework.

:D

Remember, time is an illusion, lunchtime doubly so

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101 Jan 06, 2012 at 21:53

Of course, because I love to prove myself wrong: something that may be faster than light.

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101 Jan 06, 2012 at 22:29

Only two things are infinite: the universe and human stupidity. And I’m not sure about the former
- Albert Einstein.

Somehow, it always seem intuitive to people that space is relative, but they just can’t grasp the fact that time is relative as well (and that is the whole point - saying that light is relative is nonsense). If you move at relativistic speeds with respect to an observer, your passage of time tends to slow down with respect to that observer. You don’t notice that yourself, because every physical process, including those in your brain, is slowed down as well (it’s like assuming a fixed frame time even though the computer you’re running on is not fast enough to process the frame in that amount of time - the game thinks it’s running 30FPS, while in reality it’s more like 10FPS ;)). So you just percieve one second just as being one second, but for that observer, your second might take two of his seconds.So, if someone steps into a rocket and takes a year long journey at near lightspeed and then returns to earth, he has aged a year, but all of his friends and family might have gone to pass. This is what Einstein predicted in his theory of special relativity and has been proven time and time again. This also makes it very feasible to travel into the distant future, the only problem is you probably can’t go back. Well, unless you travel far enough into the future for humanity to have actually invented time travel :P.

Acceleration makes up for an interesting effect as well. It seems that, under an accelerated frame of reference (including a gravitational potential), time is slowed down as well. That is why a clock on earth ticks slightly slower than a clock in outer space. GPS satellites (which as you might know work by simply telling their time and position so a receiver can triangluate his position based on the time difference of the messages he recieved of the different satellites and their actual positions), orbiting earth at a very large distance where there the gravitational pull is lower, need to correct for their faster passage of time. This is what Einstein predicted in his general theory of relativity.

For you to reach light speed with respect to an external observer, you’ll need an infinite amount of energy and your passage of time will slow down to a near complete halt. For a photon traveling at light speed, there is no passage of time. So, in a way, from the photon’s point of view he reaches his destination instantly, regardless of the traveled distance. That is also why a photon can’t decay - there is no passage of time for a physical process to make it decay. And for this very same reason we can detect the muons that are a result of cosmic rays colliding with particles high up in our atmosphere. Even though they decay in a fraction of a second (their mean lifetime is 2.2 nanoseconds - a particle at the speed of light will only be able to travel \~65cm in that timeframe), they move so fast that they are able to reach the surface of the earth because their passage of time is slowed down enough to keep them alive long enough.

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151 Jan 07, 2012 at 10:03

:)

It always amuses me (and makes my head ache) when people start talking about the big bang.

They start of by talking about this hot dense state and then after a few nanoseconds time starts.

But if time hasn’t started yet, how can a few nanoseconds pass?

errrr….

Think I’ll stick to programming.
:D