Science question need some nerds.

[Deleted]

The universe is like an expanding sort of in-perfect bubble. Beyond that I suppose would be the multiverse theory, which if your head wasn't already blown from our own universe then I'd wait on that. Then multiverse must be in something else right? So, one step at a time, but the argument is kind of believable in that we thought we were the only planet, then we found more, thought we were the only solar system, then found more, thought we were the only Galaxy, ect.

why does the universe, or multiverse have to be expanding into anything? Thats purely a result of imagining it like a bubble, ie having an inside and outside. Much like you see those plots of planets warping spacetime into a funnel, sure its useful in visualising it, but its nothing like that in reality.

The universe or multiverse can be expanding, and there be nothing to expand into, there does not have to be an outside, just because you perceive the universe as having an inside because you picture it like a bubble.

[Kuntantee]

What? just because I can make a banana look like an orange does not make it an orange.

Chromaticy is due to the difference between frequencies of a light waves. Luminosity is due to the power emitted by a light-wave. I am pretty sure these properties are also manifested in a sound wave, which can be used to create a pictorial representation.

[Lindon]

Chromaticy is due to the difference between frequencies of a light waves. Luminosity is due to the power emitted by a light-wave. I am pretty sure these properties are also manifested in a sound wave, which can be used to create a pictorial representation.

Are you being deliberately dense? A color is defined by the wavelengt of the light that matter emitts/reflects. Sound as a mechanical wave does not have any form of color attached to it since it behaves in a very different way.

My first reply was to correct you for saying that "it depends on the frequency", but it seems that you are adamantly trying to use strawman arguments to ascertain your point.

Edit: Furthermore, even saying that it "depends on the frequency" is another mistake since, compared to light, sound has no constant speed.
Whereas you can't just use the frequency to determine the wavelenght of sound.

[Azadina]

I don't even understand the question... :P

When did Earth race light? :P

It's supposed to be silly, like the original question

Earth won because it started on the finish line, while the light went all the way across the track (from sun to earths position)

[Kuntantee]

Are you being deliberately dense? A color is defined by the wavelengt of the light that matter emitts/reflects. Sound as a mechanical wave does not have any form of color attached to it since it behaves in a very different way.

My first reply was to correct you for saying that "it depends on the frequency", but it seems that you are adamantly trying to use strawman arguments to ascertain your point.

Edit: Furthermore, even saying that it "depends on the frequency" is another mistake since, compared to light, sound has no constant speed.
Whereas you can't just use the frequency to determine the wavelenght of sound.

I am not sure what you are trying to say. I know sound and light waves are different. However, the physical properties that produce color and intensity, which only happens in our brain, is not exclusive to light waves. There is no color outside of a neural system. The concept doesn't exist. Exploiting the process in our brain, creating colors based on various physical properties, you can create pictorial representation from any sort of wave-like phenomenon (or vice versa), which is a fact and has implementations.

[May90]

Are you being deliberately dense? A color is defined by the wavelengt of the light that matter emitts/reflects. Sound as a mechanical wave does not have any form of color attached to it since it behaves in a very different way.

Hmm? How do you think we hear all that variety of various sounds? Because the frequencies vary. When you play piano, the notes to the right cause the piano to emit the sound of higher frequency, hence you hear the "upper" tones. Same way, as the frequency of light increases, it becomes "less red" and "more blue/violet".

Now, of course, the actual mechanism behind sound waves is different from that of light waves: light is carried by elementary particles (photons), while sound is carried by disturbances of molecules spreading across - in condensed matter, you can describe it in terms of quasi-particles ("phonons"), but those aren't actual particles you can measure.

However, yes, sounds, just like light, can have different frequencies, and you will perceive it differently. And in matter, just like light, sounds "effective speed" may vary with frequency, due to dispersion.

[Lindon]

I am not sure what you are trying to say. I know sound and light waves are different. However, the physical properties that produce color and intensity, which only happens in our brain, is not exclusive to light waves. There is no color outside of a neural system. The concept doesn't exist. Exploiting the process in our brain, creating colors based on various physical properties, you can create pictorial representation from any sort of wave-like phenomenon (or vice versa), which is a fact and has implementations.

Yes, color is how the animal brain interprets different wavelengths of light. Color is by definition the different wavelengths of light (or frequency if you prefer that) interacting with light receptors. Whether you can attach color to soundwaves is irrelevant to the question at hand.

You replied "Depends on the frequency" to what color noise is. That is factually wrong as per the definition of color.

Hmm? How do you think we hear all that variety of various sounds? Because the frequencies vary. When you play piano, the notes to the right cause the piano to emit the sound of higher frequency, hence you hear the "upper" tones. Same way, as the frequency of light increases, it becomes "less red" and "more blue/violet".

How did what I said contradict what you said?

[Azadina]

From what I've understood, it's not so much that light can't exceed C, as much as light (and other massless particles) MUST travel at C, no faster, no slower.

Technically, light does slow down when it enters the atmosphere, or water, or such.

You might argue that it's speed never changes, but as it now takes it longer to travel than in a vacuum, one can also argue it's going slower.

[May90]

How did what I said contradict what you said?

Maybe I've misunderstood your argument. I'm not sure what you were trying to say by "sound does not have any form of color attached to it". I thought you were talking about frequencies.

[Lindon]

Maybe I've misunderstood your argument. I'm not sure what you were trying to say by "sound does not have any form of color attached to it". I thought you were talking about frequencies.

Ah. I meant that as in the definition of color. As in how the brain interprets the signals sent by the light receptors when introduced to a light source.

[Whiskeyjack WN]

Then how are you able to go faster than time if you are going faster than light? I don't understand this theory from Einstein how can light be the fastest thing in the universe when it takes light thousands of years just to reach from one end of a galaxy to another. Wouldn't going faster than time mean you are going faster than something that can reach a destination from one edge of the universe to another in an instant?

You are a little off in your understanding of time. it is a matter of perspective. if you travel at the speed of light, then time 'stops'. The time it takes light to travel between galaxies is from our perspective here on earth.
However from the perspective of that photon of light, it travels that distance instantaneously, time does not exist for that photon and don't forget distances contract. From the perspective of that photon of light, it can travel anywhere in the universe instantaneously.

[May90]

Ah. I meant that as in the definition of color. As in how the brain interprets the signals sent by the light receptors when introduced to a light source.

In this sense, I agree: sound doesn't have color as such. I guess extremely dense sound waves could distort the medium to the point of essentially becoming visible and colored, but it wouldn't be "sound's color" still.

[Danner]

So my question is how can light be as fast as time when light is traveling from let's say earth to pluto it still requires a set amount of time before it reaches it. If light were as fast as time wouldn't it reach Pluto instantaneously? How could traveling faster than light mean going faster than time when light isn't as fast as time itself?

Several questions here. But you are mixing up some terms. Let's sort out that first.

Speed (aka velocity) is a positional change over time.

speed = distance / time

The point here is, time is not the same as speed. Speed (velocity) is how far you move during an interval of time. I see several others have pointed this out to you.
Or in laymans terms, if your car moves at 1000 meters / hour, that means that in one hour, it will move a distance of 1000 meters. That's a pretty crappy car engine, by the way.

Light also has a speed. It's about 300 000 meters per second, scientists tend to use the symbol "c" to denote the speed of light because writing a six digit number is a hassle.

But what is light anyway?

The simple (and inaccurate) answer is that light consists of billions of tiny particles called "photons", each moving at the speed of light though space. If you hold a flashlight, it emits a continuous stream of photons moving away from you at a speed to 300 000 m/s. If you point that flashlight at Pluto, and we assume pluto is 6 billion kilometers away from earth...

... then the photons emitted from your flashlights would reach pluto in about five and a half hours.

speed = distance / time

If we fill in the numbers we have in this equation and solve for time...

300 000 m/s = 6 000 000 000m / time
time = 6 000 000 000m / 300 000 m/s 
time = 19667 s
time = 5.46 hours

The point here - light is not instant. Light has a speed. It's a super fast speed, but a speed nonetheless. When the distances are vast, even light will take a while to get there.

Next is where Einstein comes in

Now, I'll put this in a collapse block. This part is only relevant if you want to know about the time travel part of your question.

Spoiler: 

Basically, Einstein figured out something that is so mind-boggling that we still have issues getting to terms with it.

The speed of light is the same for all observers.

This may not seem weird at first, but it patently is.

Imagine a train driving along the countryside. The train drives at 30 m / s.
On top of that train is a baseball pitcher!
In front of the train (slightly to the side so he won't be run over) is a baseball catcher.

The pitcher throws a ball at the catcher. He throws balls hard, at a speed of 40 m/s.

What is the speed of the ball?

For the pitcher, the ball moves at a speed of 40 m/s. That's what he threw it at.
The poor catcher, that ball has a speed of 70 m/s, because the speed of the train is added to the ball.

That will be painful to catch!
Basically, your point of reference matter when calculating speed.

An alien hovering in front of the earth his spaceship was witness the entire deal. He was watching the earth, moving towards him at a speed of 460 m/s. For him, the ball speed would be affected by the speed of the earth. So if you ask him, the ball actually run at a speed of 530 m/s.

Enter Einstein. He found that the speed of light is always* 300 000 m/s. For the pitcher. For the catcher. For the alien watching it all - same speed.

Imagine the pitcher waving a flashlight instead. This shoots out photons, as discussed. Moving at 300 000 m/s. No matter how fast the train goes, the phonots move at the same speed. The pitcher sees photons move at 300 000 m/s. The catcher sees photons move at 300 000 m/s. The alien sees photons move at 300 000 m/s.

Imagine the pitcher throwing a ball at the speed of light instead. The pitcher sees a ball moving at 300 000 m/s.
The catcher will also see a ball moving at 300 000 m/s. It doesn't matter how fast the train goes, they both agree on the speed.

That's odd, because this is contrary to what we just found would happen to the normal baseball!

The thing here is that when you get to super high speeds, weird things happen. Basically, your time (as seen by others) slows down as your speed increases (compared to them)**. The faster you move (compared to a bystander), the slower your time runs (compared to the bystander). At the speed of light, your time would actually grind to a halt. We don't really notice this effect at the slow speeds we use on earth, but the effect has been observed by sending some extremely precise atomic clocks up around the earth a few times in some super fast fighter jets. The clock that traveled fast ended up with less ticks on it than the clock they left at the base.

And here's the fun part of course. If your time runs slower the closer to speed of light you move, if you somehow managed to run faster than the speed of light, that mathematically means your time should move backwards, so we should go backwards in time? It's a thought experiment, but the logic makes sense right? It's like a car that goes slower and slower and slower until it stops. Then starts backing up instead.

Problem is, since time go slower and slower the faster you move them, you need more and more energy to counteract that effect, and that effect gets very very noticeable the closer you get to the speed of light. Mathematically, you need an infinite amount of energy to get any matter up and moving at the speed of light. So sending any object at the speed of light is impossible! Best thing we can do is to get close!

Also, our baseball players are incinerated and dies horribly. Rest in peace. .


But you said light (photons) moved at the speed of light

They do.

The thing about photons is that they do not have any mass. They do not weigh anything (this should be obvious, you are not going to get crushed by sunlight).
Photons are actually not particles at all. They are electromagnetic radiation; waves and fields. Pure energy if you like. They move at the speed of light, but they do not move any slower than that*. So they do not follow the same physical law as the baseball. Light moves at the speed of light. But anything with mass cannot, unless you have an infinite amount of energy to burn, getting there.

Unless some new clever person figure out a way of doing it. Who knows?

---

*) In a vacuum at least.
**) Your "space" also shrinks. The term "space time" was invented because it doesn't make much sense to separate them, it's all a matter of perspective. It's easier to just think of it as time slowing down though. That's something we can wrap our heads around easier.

[DeadmanWalking]

I think people are enjoying insulting the OP a bit too much. God forbid if someone doesn't understand something that they ask for an explanation. Sometimes intellect isn't knowing things, sometimes intellect is seeking answers. Only those who don't care to seek knowledge are stupid.

[staticflare]

You are a little off in your understanding of time. it is a matter of perspective. if you travel at the speed of light, then time 'stops'. The time it takes light to travel between galaxies is from our perspective here on earth.
However from the perspective of that photon of light, it travels that distance instantaneously, time does not exist for that photon and don't forget distances contract. From the perspective of that photon of light, it can travel anywhere in the universe instantaneously.

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?

- - - Updated - - -

I think people are enjoying insulting the OP a bit too much. God forbid if someone doesn't understand something that they ask for an explanation. Sometimes intellect isn't knowing things, sometimes intellect is seeking answers. Only those who don't care to seek knowledge are stupid.

Ignore the trolls something I've learned to do a long time ago saves alot of stress.

[unbound]

So my question is how can light be as fast as time when light is traveling from let's say earth to pluto it still requires a set amount of time before it reaches it. If light were as fast as time wouldn't it reach Pluto instantaneously? How could traveling faster than light mean going faster than time when light isn't as fast as time itself?

For clarity, making the Kessel run in less than 12 parsecs is not scientifically sound.

[Elegiac]

For clarity, making the Kessel run in less than 12 parsecs is not scientifically sound.

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.

[Ryme]

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?

From the perspective of the photon, it would be instant. From the photon's perspective it's entire life and history is contained in a single point of time; it flashes in and out of existence. It's the outside observer who sees it moving over a few hundred thousand years.

Though it must be said that there are issues here with the uncertainty principle that we're not accounting for.

[Slant]

It's supposed to be silly, like the original question

Earth won because it started on the finish line, while the light went all the way across the track (from sun to earths position)

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.

[staticflare]

From the perspective of the photon, it would be instant. From the photon's perspective it's entire life and history is contained in a single point of time; it flashes in and out of existence. It's the outside observer who sees it moving over a few hundred thousand years.

Though it must be said that there are issues here with the uncertainty principle that we're not accounting for.

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