Science question need some nerds.

[Adam Jensen]

So what you're saying is if there were a light powerful enough to travel from one end of a galaxy to another the light would reach that other end instantaneously but from what we see it would take about a thousand years? So basically light is completely instant?

Light is instant only from light's PoV because light doesn't experience time.

But outside observers do experience time and light would thus take billions of years to cross the universe.

This sounds counterintuitive, but then, so does General Relativity.

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How does an electron have mass but a photon does not?

Electrons interact with the Higgs field. Photons do not. Why the difference? I don't know if we know.

[May90]

How does an electron have mass but a photon does not?

I don't think this is a "why" that can be answered. Sure, there is the Higgs field explanation, but then, again, why does the Higgs field work as it does?
It is just a property of nature, that's the best we can say, really.

Granted, electron's mass is pretty small in the grand scheme of things, so in many situations you can safely approximate it as a massless particle. It even leads to funny situations like that supernova, from which electrons reached us faster than the light: light was slowed down in the interstellar medium, while electrons were not.

[Garnier Fructis]

Light is instant only from light's PoV because light doesn't experience time.

But outside observers do experience time and light would thus take billions of years to cross the universe.

This sounds counterintuitive, but then, so does General Relativity.

Honestly it's better not to even talk about light's point of view, because that notion is undefined in relativity.

[May90]

Honestly it's better not to even talk about light's point of view, because that notion is undefined in relativity.

There is still a tiny possibility that a photon has a very-very tiny mass we haven't been able to detect yet. So, who knows!

[Azadina]

I'm sorry, I'm letting these trolls rile me up so I don't even notice a plain joke when it slaps me in the face.

*hugs* The joke was to match the scenario with the originality of the thread. I mean, how stupid is it to question the speed of light, if you intentionally come up with ridiculous scenario where you make it "lose" to something that moves slower

[Garnier Fructis]

There is still a tiny possibility that a photon has a very-very tiny mass we haven't been able to detect yet. So, who knows!

Oh, sure. But as long as we're answering questions on the assumption that SR is true as is, I think it's better not to talk about undefined concepts.

[druenos]

So basically it is impossible to go ahead in time correct? It's impossible to go into the future?

All travel is a time machine. The faster you go the slower time goes for you relative to everyone else. If you travelled at the speed of light for a year, 100 years would have passed on Earth so you basically travelled through time, it's not time thats travelling, its you.

[AwkwardSquirtle]

They attempted to retcon an explanation by saying that the records for the Kessel run are a function of the distance it takes to cross it.

Also, Han shot first.

That does work. The shorter distance due to being closer to a black hole cluster is valid, if unorthodox.

[Whiskeyjack WN]

So what you're saying is if there were a light powerful enough to travel from one end of a galaxy to another the light would reach that other end instantaneously but from what we see it would take about a thousand years? So basically light is completely instant?

Ryme explained this nicely

Honestly it's better not to even talk about light's point of view, because that notion is undefined in relativity.

This is where we look to Special Relativity. Lights PoV is considered here.

How does an electron have mass but a photon does not?

As for a Photon been massless. that is a traditional description of the photon. The modern point of view falls under relativistic mass, which describes the change in the particles mass from its rested and moving state.

Special Relativity is a very interesting subject and worth looking into, especially if you want to learn more on the properties of light. There are a lot of good sources of information on Special Relativity and it isnt as complicated as Relativity so it is a good place to start reading (if you have an interest).

[Garnier Fructis]

This is where we look to Special Relativity. Lights PoV is considered here.

Light's PoV doesn't make sense in Special or General relativity.

[staticflare]

*hugs* The joke was to match the scenario with the originality of the thread. I mean, how stupid is it to question the speed of light, if you intentionally come up with ridiculous scenario where you make it "lose" to something that moves slower

If you think the thread is "stupid" then stop posting. I just wanted to ask some questions that I've always been curious about. You filling up the thread with shitpost is only wasting your time not mine.

[Azadina]

If you think the thread is "stupid" then stop posting. I just wanted to ask some questions that I've always been curious about. You filling up the thread with shitpost is only wasting your time not mine.

Oh, I am shitposting? Mind you, I'm not the one who calls people nerds, who managed to pay attention in elementary school.

You chose the direction to take with your title and OP.

[Elegiac]

Oh, I am shitposting? Mind you, I'm not the one who calls people nerds, who managed to pay attention in elementary school.

You chose the direction to take with your title and OP.

Are you not proud to be a nerd? I am.

[Whiskeyjack WN]

Light's PoV doesn't make sense in Special or General relativity.

Define make sense?

Special Relativity considers lights pov, or more to the point considers our pov of an object if we and that object were both moving at the speed of light.
That said, it is a mind fuck, seeing all sides of an object at once and the complete contraction of distances. But it does consider it, making 'sense' of these theories is inherently impossible, unfortunately.

[Azadina]

Are you not proud to be a nerd? I am.

It's not usually used as a compliment tho. Especially not if passing elementary school equals you being nerd. What do people really expect when they don't seem serious about a subject when starting it?

[zebreck]

Gonna leave this here for you OP. Excellent youtube videos by PBS explaining most of the things you don't know about relativity.

https://www.youtube.com/channel/UC7_...ThXybpVgjHZ_7g

[Whiskeyjack WN]

It's not usually used as a compliment tho. Especially not if passing elementary school equals you being nerd. What do people really expect when they don't seem serious about a subject when starting it?

Why do people go out of their way to be offended nowadays? Its as if the whole world is in the business of being offended...

And your Elementary school taught you relativity? impressive.. I had to go to uni for that.

[Adam Jensen]

Are you not proud to be a nerd? I am.

Oh! What an insult being labeled "smart!"

[Garnier Fructis]

Define make sense?

Special Relativity considers lights pov, or more to the point considers our pov of an object if we and that object were both moving at the speed of light.
That said, it is a mind fuck, seeing all sides of an object at once and the complete contraction of distances. But it does consider it, making 'sense' of these theories is inherently impossible, unfortunately.

It doesn't make sense because 'light's PoV' is not defined in special relativity. In fact, according to the postulates of relativity, such a reference frame is impossible. Light moves at c through vacuum in every inertial reference frame. This is one of the foundations of the theory. Which is to say, light goes at speed c in every point of view. So if you were to have a reference frame for light, it would simultaneously have speed 0 and speed c.

[Azadina]

Why do people go out of their way to be offended nowadays? Its as if the whole world is in the business of being offended...

And your Elementary school taught you relativity? impressive.. I had to go to uni for that.

I'm not offended, I was having fun along with it. Until someone gets offended for me doing the same things as OP did.

You mean you weren't taught the meaning of words time and speed before uni? That is impressive. Those are the things OP struggled with. The meaning of those two words.