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the speed of light question

y0ssar1an22

a question that has puzzled me for a while...

1: car A and car B have a velocity towards each other of 100 kph. they are approaching each other is 200kph.

2: if car A and car B are doing the same, but at the speed of light why are they not approaching each other at (2)(speed of light)?

if the rules of physics hold for scenario 1, why not scarios 2?

is there a simple explanation here?

i dunno, maybe we just don't have an answer?

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[Deleted User]

There's a different formula for relativistic objects
Newton is out the window

Feisar

They are approaching each other at twice the speed of light. I don't get the question tbh.

Gregor Samsa

This is exactly what led Einstein to develop the theory of relativity: imagining what it would be like to travel at the speed of light. He quickly realised the old rules (Newtonian mechanics) are an approximation that only work for objects travelling significantly below the speed of light, and the speed of light itself is not only a limit, but a universal constant.

This page explains it, and why, when you’re dealing with the relative speed of two photons, the answer is still c (the speed of light)

https://www.physicscentral.com/experiment/askaphysicist/physics-answer.cfm?uid=20130130105151

Rodney Bathgate

What make and model of car?

Gregor Samsa

Feisar wrote: »

They are approaching each other at twice the speed of light. I don't get the question tbh.

They’re not. There is no “twice the speed of light”. It’s a hard limit. Their relative velocity is still the speed of light.

Feisar

Gregor Samsa wrote: »

They’re not. There is no “twice the speed of light”. It’s a hard limit. Their relative velocity is still the speed of light.

I'm no genius so please bare with me.

Lets imagine two stars are born and both start pumping out light. Surely the light will meet in the middle between them?

bobbyy gee

your confusing yourself

https://www.space.com/15830-light-speed.html

Gregor Samsa

There’s an interesting phenomenon called time dilation that happens the faster you travel. It’s not something you can notice at human speeds (unless you’re measuring with an incredibly accurate atomic clock), but the faster you go, the slower time goes relative to observers travelling slower than you. If you go at 90% of the speed of light, your perception and experience of time is half of a static observer. You’ll actually age half as slow as them. If you travel at the speed of light, for you, time stops, and you’re therefore bot able to observe anything in the universe. Basically at that speed, for you, nothing else exists except yourself, and time is infinite.

If you have any mass, your mass will also become infinite at the speed of light. It would therefore take an infinite amount of energy to get you there. Your length also reduces in the axis you’re travelling the faster you go. And again, the effect is infinite at the SOL.

So, if you were a solid object of any size, it would take infinite energy to get you to the speed of light, and once you got there, you’d have infinite mass, zero length, time would stop and to you the universe would cease to exist. This clearly means that it’s impossible for anything with mass to travel at the speed of light. It also shows that nothing can travel faster than light (it would take more than infinite energy to do it, which can’t exist, and you’d end up more than infinitely massive and less than zero in length - again, things that just can’t happen)

Fortunately, photons and other particles that do travel at that speed don’t have any mass, so they don’t have to worry about the physical effects.

Gregor Samsa

Rodney Bathgate wrote: »

What make and model of car?

that Tesla Roadster that Musk launched into space.

Gregor Samsa

Feisar wrote: »

I'm no genius so please bare with me.

Lets imagine two stars are born and both start pumping out light. Surely the light will meet in the middle between them?

Yeah, it will* But the relative velocity of photons from both stars is still just the speed of light. The equation is in the link I posted above.

*it will relative to an outside observer not travelling at the speed of light, like you or I. To the photons themselves, they won’t meet as there is no time for them, and they don’t perceive themselves as moving at all.

Feisar

Gregor Samsa wrote: »

Yeah, it will* But the relative velocity of photons from both stars is still just the speed of light. The equation is in the link I posted above.

*it will relative to an outside observer not travelling at the speed of light, like you or I. To the photons themselves, they won’t meet as there is no time for them, and they don’t perceive themselves as moving at all.

You have damaged my fragile little mind!

[Deleted User]

y0ssar1an22 wrote: »

a question that has puzzled me for a while...

1: car A and car B have a velocity towards each other of 100 kph. they are approaching each other is 200kph.

2: if car A and car B are doing the same, but at the speed of light why are they not approaching each other at (2)(speed of light)?

if the rules of physics hold for scenario 1, why not scarios 2?

is there a simple explanation here?

i dunno, maybe we just don't have an answer?

Each cars is still only travelling at 100kph. And if they were travelling at the speed of light neither car breaks the speed of light as individual objects.

y0ssar1an22

bluewolf wrote: »

There's a different formula for relativistic objects
Newton is out the window

that's the exact thing i'm confused about. all those equations of newton hold true, until they dont.

you cant have it both ways surely? One must be incorrect.

does newton's physics go out the window at a certain speed?

if they are related, is there an equation that shows that?

or do we not really know? one of those known unknowns?

y0ssar1an22

Rodney Bathgate wrote: »

What make and model of car?

cinquecento, its lovely

y0ssar1an22

Gregor Samsa wrote: »

There’s an interesting phenomenon called time dilation that happens the faster you travel. It’s not something you can notice at human speeds (unless you’re measuring with an incredibly accurate atomic clock), but the faster you go, the slower time goes relative to observers travelling slower than you. If you go at 90% of the speed of light, your perception and experience of time is half of a static observer. You’ll actually age half as slow as them. If you travel at the speed of light, for you, time stops, and you’re therefore bot able to observe anything in the universe. Basically at that speed, for you, nothing else exists except yourself, and time is infinite.

If you have any mass, your mass will also become infinite at the speed of light. It would therefore take an infinite amount of energy to get you there. Your length also reduces in the axis you’re travelling the faster you go. And again, the effect is infinite at the SOL.

So, if you were a solid object of any size, it would take infinite energy to get you to the speed of light, and once you got there, you’d have infinite mass, zero length, time would stop and to you the universe would cease to exist. This clearly means that it’s impossible for anything with mass to travel at the speed of light. It also shows that nothing can travel faster than light (it would take more than infinite energy to do it, which can’t exist, and you’d end up more than infinitely massive and less than zero in length - again, things that just can’t happen)

Fortunately, photons and other particles that do travel at that speed don’t have any mass, so they don’t have to worry about the physical effects.

your perception and experience of time is half of a static observer: has that been proven, or a conjecture?

i think infinity shouldn't be allowed. it essentially means 'going that way for a long time, but we really know' so lets call it quits'.

air

y0ssar1an22 wrote: »

that's the exact thing i'm confused about. all those equations of newton hold true, until they dont.

you cant have it both ways surely? One must be incorrect.

does newton's physics go out the window at a certain speed?

if they are related, is there an equation that shows that?

or do we not really know? one of those known unknowns?

Newton"s equations don't work af any speed if you need absolute accuracy but they are a close enough approximation of reality to remain useful for very many day to day terrestrial applications.

y0ssar1an22

air wrote: »

Newton"s equations don't work af any speed if you need absolute accuracy but they are a close enough approximation of reality to remain useful for very many day to day terrestrial applications.

i always thought physics was essentially 1 + 1 = 2; a physical quantifiable 'thing' that you can solve for?'

it seems, there is so many unknowns, that people are happy to go along with the that, without any proof?

[Deleted User]

They said the speed of sound could not be broken.

Dilithium crystals ftw.

jelem

air wrote: »

Newton"s equations don't work af any speed if you need absolute accuracy but they are a close enough approximation of reality to remain useful for very many day to day terrestrial applications.

" reality" All human constructs in this thread fail to allow we percieve
mathematics as we know it as our means to answer a question.
we are looking at it as humans looking at ants and as there is no
finite mathematical balanced answer just "near" approximations
the likes of "nearest decimal point" , it can be seen that an unknown
mor advanced "entity" may be looking at us whom have the actual factual answer
which is a whole number without minute decimal approximations.
We as humans are not there yet and as the theory of space\time being "folded"
we have No solid method of actual speed measurement and only use light as a make do
until we have gained knowledge.
the human has to rely on subjective relevance from human perspective for all our
decisions and measurements for which we are constantly reminded by disaster
when approximation does not "cut it". we may go to ufo theory as a means to
explain the unexplained which we cannot figure at this time.
this thread got too deep on trying to explain to a person whom sought an answer
for something they mentally cannot picture themselves and make a request above their understanding of
the question.
"give me an answer i dont understand" is the easy means for humans to get by
with having to think "basics" for themselves.
( just bent and folded space, brushed the surface of mars ready for the expensive waste of money human trip
for which as earth is on path to end we should be spending on sustaining life and increasing speed heading out of our
dead system towards where there may be a liveable planet to relocate as human thought has after newton\fraud etc.
seemed to have become idle which may be due to political ignorance\corruption etc.).
All the thinkers and publishers "last 25-30 years" show fear and seem produce "politically correct and acceptable"
work Only. We are doomed. lol

[Deleted User]

^^^ this dead system has another 5 billion years. Be grand.

air

y0ssar1an22 wrote: »

i always thought physics was essentially 1 + 1 = 2; a physical quantifiable 'thing' that you can solve for?'

It is in this respect, relativity is 100% accurate at present & is used in things like GPS, it wouldn't work if not adjusted for it's effects.

y0ssar1an22 wrote: »

it seems, there is so many unknowns, that people are happy to go along with the that, without any proof?

Nobody goes along with anything without proof.
Einstein developed relativity through a series of thought experiments.
Actual experiments and observations proved him to be correct & the theory was then put into practice in many technologies that are in use today.

There are infinite numbers of unknowns of course though, that's the beauty of our universe & the never ending quest for knowledge.

Overheal

Rodney Bathgate wrote: »

What make and model of car?

A souped up reliant robin with a Mk II warp core

Cookie_Monster

Gregor Samsa wrote: »

They’re not. There is no “twice the speed of light”. It’s a hard limit. Their relative velocity is still the speed of light.

In theory.

blinding

y0ssar1an22 wrote: »

a question that has puzzled me for a while...

1: car A and car B have a velocity towards each other of 100 kph. they are approaching each other is 200kph.

2: if car A and car B are doing the same, but at the speed of light why are they not approaching each other at (2)(speed of light)?

if the rules of physics hold for scenario 1, why not scarios 2?

is there a simple explanation here?

i dunno, maybe we just don't have an answer?

In the Matrix of our Universe every Observer can only observe a Maximum Speed as the Speed of Light.

This is a rule of our Matrix / Universe. Other Matrix’s / Universes may have different rules.

After I have completed my sentence in this one for my High Crimes and Misdemeanours I hope to explore other Universes / Matrix’s !

Hamsterchops

186,000 miles per second ...

Picked that up in school many moons ago.

Rodney Bathgate

y0ssar1an22 wrote: »

cinquecento, its lovely

Schumacher Edition?

Wanderer78

y0ssar1an22 wrote:

a question that has puzzled me for a while...

You're doing the wrong type of drugs for you, you need to find one or ten that relax your mind....

arctictree

A weird effect of relativity is that for a photon of light, time stops. So from it's point of view, it can traverse the whole universe instantly.

Wanderer78

arctictree wrote:

A weird effect of relativity is that for a photon of light, time stops. So from it's point of view, it can traverse the whole universe instantly.

This stuff always fascinated me, but by fcuk is it a mind bender, physics is weird!

Gregor Samsa

Cookie_Monster wrote: »

In theory.

Well, it’s a pretty solid theory, backed up by a massive amount of proof, observation and experimentation. The main issue with faster than light travel is that it would violate causality: things would happen before the thing that’s caused it.

There are theories that propose hypothetical faster then light particles called Tachyons, but all are problematic.