Unexpected Findings in “Little” Big Bang Experiment Leaves Physicists Baffled

originally posted by: Terpene
a reply to: face23785

Did they though?

Yes, they did.

if they can change one vector of acceleration why not the other?

Are you asking why--if they can slow it down--they can't speed it up beyond c?

a reply to: face23785

I'd rather do that than insist that just because I can't understand something means science has it wrong. That's the height of human arrogance and ultimately closed-minded.

I agree and I hope you weren't implying that as my relationship with science.

a reply to: face23785

I'm asking how they changed the negativ acceleration vector?

How fast was the light after it came out of the gas?

originally posted by: Terpene
a reply to: face23785

I'm asking how they changed the negativ acceleration vector?

How fast was the light after it came out of the gas?

There's actually several different methods for slowing it down dramatically. If you google "physicists slow light," you will find various articles of different age as they've developed different methods for doing it. Some can slow light down to highway speeds.

It's worth noting you don't need a fancy lab to slow light below c. Light slows down as it passes through any medium. That includes air, glass, and water. As I noted, c is commonly referred to as the speed of light by us laymen, but it is more accurately the speed of light in a vacuum. Passing it through anything slows it down.

a reply to: face23785

So after the medium, the photon is slowed down and keeps that speed indefinitely? Would a clock shone upon with that light appear to move backwards or slower or faster?

Let's try to settle the discussion.

All electromagnetic waves travel at the same speed: the speed of light. This is always true, whether you are travelling towards or away from the source. This sounds paradoxical: were you travelling away from the light source at nearly light speed yourself, you would expect that the light would only slowly overtake you; however, it rushes past at light speed itself. It is important to read this carefully because this is counter-intuitive.

If you were riding on a photon and switch on a searchlight, the searchlight will emit a beam that you will never overtake it because the beam is travelling at the speed of light, RELATIVE TO YOU, regardless of you travelling too at the speed of light. Please, retain these words in your mind: relative to you.

The invariance of the speed of light with respect to the speed of source or observer is a result, in part, of distances contracting. Distances and time intervals as recorded by observers at different speeds take on different measures; what is space for one observer is a mix of space and time for another. In the above case (you riding on a photon) common sense fails since independent of how fast you move or in what direction, your relative speed to a light beam is invariant.

It is the fact that c is finite that makes the structure of space and time depend upon our speed; it is because c is finite but large that you normally are unaware of its effects. The lesson is this: when talking about photons, speeds, and positions, always bear in mind that they are all computed RELATIVE TO YOU and that whatever you do, wherever you happen to be, whatever the speed you move at, the speed of light will always be invariant. Even if you were a photon yourself.

originally posted by: Terpene
a reply to: face23785

So after the medium, the photon is slowed down and keeps that speed indefinitely?

No.

a reply to: Direne

If an object flew our way with lightspeed, and a photon hit the surface and gets reflected our way wouldn't it have to already know every other relative position and adapt its speed to them? Otherwise we wouldn't see it coming.

I find them super funny thought experiments, they always get me in a twist...

a reply to: face23785

So what? after it exits the medium, it resumes light speed?

a reply to: face23785

As someone pointed out, you're forgetting about time dilation. This effect is negligible for an auto collision, but super important at relativistic velocities.

Thanks for replying. 'Time dilation' is another new term for me.

The 'tadpole dish' was when I sorta got the idea of the 'observer's point of view'.

a reply to: Terpene

If an object flew our way with lightspeed, and a photon hit the surface and gets reflected our way wouldn't it have to already know every other relative position and adapt its speed to them?

No, for you should remember that for the photon everything is instantaneous, time does not exist, and not even time. As a photon, the way you experience reality is totally different: you are an instantenous all-simultaneous being.

I'm not totally sure of the geometry of the problem you pose, though. I feel you think it is the photon the one doing the magic in order to always sustain the maximum speed, and that therefore it must "compute" the position and distances to surrounding objects in order to always show the same maximum speed if measured by any of those objects.

Such is not the situation. See, photons always travel along geodesics, minimizing the time it take them to reach from point A to point B. The speed of light is not something that belongs to the nature of photons: it is something forced upon them by the geometry of space-time. Namely, it is the very fabric of space-time that imposes a maximum limit to the speed of particles. The special property of photons is that they have no rest frame, and remember it is essential to specify the rest frame of any time measurements. The time that an event occurred is dependent on the rest frame of the observer. If the photon has no rest frame all the events are instantaneous for the photon. For the photon there are no events, no History, no time. It is very sad for the poor photon to not be able to perceive the wonderful Universe it itself creates because, to all effects, the photon is blind and cannot see or experience anything.

Worse: the poor photon does not even know it is travelling. Its existence is instantaneous or, if you prefer, a photon is just pure existence... in no time and no space. Photons are essentially dead.

To be a photon is probably the saddest fate in this Universe.

a reply to: NobodySpecial268
It's the frame of reference that's important here..

Neither body is exceeding the speed of light either in their own frames, or as an observer in another frame.

a reply to: gspat

I can see that, and how things resove by the rule. The two photons each travelling west and east at 186,000 m/s resolve into an expansive sphere that expands in all directions at the speed of light. I guess too, the universe is a similar closed space expanding at the speed of light.

originally posted by: Direne
Let's try to settle the discussion.

All electromagnetic waves travel at the same speed: the speed of light. This is always true, whether you are travelling towards or away from the source. This sounds paradoxical: were you travelling away from the light source at nearly light speed yourself, you would expect that the light would only slowly overtake you; however, it rushes past at light speed itself. It is important to read this carefully because this is counter-intuitive.

If you were riding on a photon and switch on a searchlight, the searchlight will emit a beam that you will never overtake it because the beam is travelling at the speed of light, RELATIVE TO YOU, regardless of you travelling too at the speed of light. Please, retain these words in your mind: relative to you.

The invariance of the speed of light with respect to the speed of source or observer is a result, in part, of distances contracting. Distances and time intervals as recorded by observers at different speeds take on different measures; what is space for one observer is a mix of space and time for another. In the above case (you riding on a photon) common sense fails since independent of how fast you move or in what direction, your relative speed to a light beam is invariant.

It is the fact that c is finite that makes the structure of space and time depend upon our speed; it is because c is finite but large that you normally are unaware of its effects. The lesson is this: when talking about photons, speeds, and positions, always bear in mind that they are all computed RELATIVE TO YOU and that whatever you do, wherever you happen to be, whatever the speed you move at, the speed of light will always be invariant. Even if you were a photon yourself.

That was good until you went off the rails with the last sentence. if you are a photon yourself, you have no valid reference frame so relativity can say nothing about what things would look like from your reference frame. In fact it's not difficult to show that relativity would fall apart if you tried to give the photon a reference frame, but only incompetent physicists claim a photon can have a valid reference frame, some don't really understand relativity.

Under the theory of relativity it makes absolutely no sense to talk about what you would see from the perspective of a photon, because you can get contradictory answers to simple questions.

See Why is time frozen from light's perspective?

Time is not frozen from light's perspective, because light does not have a perspective. There is no valid reference frame in which light is at rest. This statement is not a minor issue that can be approximated away or overcome by a different choice of words. This statement is fundamental to Einstein's theory of Special Relativity, which has been experimentally validated thousands of times over the last hundred years.

Other than that, kudos for correctly answering the question here of why .99c + .99c does not equal 1.98c and so on.

a reply to: Direne

Don't be so photonphobic.
What good is a photon without the eye to see it though . Seems to be their only purpose, but heck they got us hooked...

I dont know...
Whenever a science sais thats just how it is, or that's impossiblemy conspiratorial mind tells me there is something more. In this case something beyond the speed of light. Something we are not supposed to "see".

It would maybe just be so fast that if you don't move at the same speed you can't see it. The photons would always be a step behind, the eye becomes totally useless.

originally posted by: Direne
Let's try to settle the discussion.

All electromagnetic waves travel at the same speed: the speed of light. This is always true, whether you are travelling towards or away from the source. This sounds paradoxical: were you travelling away from the light source at nearly light speed yourself, you would expect that the light would only slowly overtake you; however, it rushes past at light speed itself. It is important to read this carefully because this is counter-intuitive.

If you were riding on a photon and switch on a searchlight, the searchlight will emit a beam that you will never overtake it because the beam is travelling at the speed of light, RELATIVE TO YOU, regardless of you travelling too at the speed of light. Please, retain these words in your mind: relative to you.

The invariance of the speed of light with respect to the speed of source or observer is a result, in part, of distances contracting. Distances and time intervals as recorded by observers at different speeds take on different measures; what is space for one observer is a mix of space and time for another. In the above case (you riding on a photon) common sense fails since independent of how fast you move or in what direction, your relative speed to a light beam is invariant.

It is the fact that c is finite that makes the structure of space and time depend upon our speed; it is because c is finite but large that you normally are unaware of its effects. The lesson is this: when talking about photons, speeds, and positions, always bear in mind that they are all computed RELATIVE TO YOU and that whatever you do, wherever you happen to be, whatever the speed you move at, the speed of light will always be invariant. Even if you were a photon yourself.

I like your descriptions. It puts the observer in the driver's seat. Much easier to understand - you just need a little imagination.

originally posted by: NobodySpecial268
a reply to: face23785

As someone pointed out, you're forgetting about time dilation. This effect is negligible for an auto collision, but super important at relativistic velocities.

Thanks for replying. 'Time dilation' is another new term for me.

The 'tadpole dish' was when I sorta got the idea of the 'observer's point of view'.

And that's exactly how it happens. There was a time when I didn't understand time dilation (I still don't understand ALL of it, but there was a time when I didn't get it at all and thought it was hogwash.) I had read and seen videos explaining it and none of it made sense until one day I saw an explanation in a documentary about Einstein that just made sense to me.

All our brains are wired different.

originally posted by: Terpene
a reply to: face23785

So what? after it exits the medium, it resumes light speed?

Correct.

originally posted by: Terpene
a reply to: Direne


Whenever a science sais thats just how it is, or that's impossiblemy conspiratorial mind tells me there is something more. In this case something beyond the speed of light. Something we are not supposed to "see".

There's a hypothetical particle called a tachyon that always travels faster than the speed of light. Maybe you'd enjoy reading about it. Seems right up your alley. It's purely theoretical, there's no evidence that it actually exists, but reading about it may answer some of your questions about hypothetical scenarios involving things moving faster than light.

I will also say that we have something in common in that I also find "that's just how it is" to be an unsatisfying answer. I always want to know why.

If you could travel the much faster speed of entanglement @ 3e+15m/s, or almost 1/3ly/s; You could reach Alpha Centauri in about 16 seconds.

originally posted by: sean
If you could travel the much faster speed of entanglement @ 3e+15m/s, or almost 1/3ly/s; You could reach Alpha Centauri in about 16 seconds.

Every time I've seen entanglement explained, it's referred to as literally instantaneous.

Where did you see it has a speed?