Seeing things in their past? You are full of beans!

[Polymath257]

Wouldn't the limit as time approaches zero be infinity, and not stop at the speed of light?

No. The limit is c because as time goes to 0, so does distance. At each speed under c, the quotient is c. So the limit is c.

 

[james blunt]

No. The limit is c because as time goes to 0, so does distance. At each speed under c, the quotient is c. So the limit is c.

Incorrect assumption, time cannot stop independent of everything else for an individual object in motion. That would be an absurd thought. The frame of now would have to pause for all, for time to stop .

 

[Kangaroo Feathers]

As you see we were wrong. The Dark Ages were after proper atoms started to form and before the first stars. No light except for the CMB, which was probably not microwave at that time, though again I could be wrong.

Visible light =/= all "light"

 

[Kangaroo Feathers]

Incorrect assumption, time cannot stop independent of everything else for an individual object in motion. That would be an absurd thought. The frame of now would have to pause for all, for time to stop .

From the perspective of the photon, time DOES stop for everything else.

Perhaps you're familiar with the twin paradox?

 

[Subduction Zone]

Visible light =/= all "light"

I know, that should have been obvious from my post that you quoted. Did you have a point?

 

[Kangaroo Feathers]

I know, that should have been obvious from my post that you quoted. Did you have a point?

That photons were present and possible during the "Universal Dark Age", their diffusion wasn't which is why we can't detect their echos now. Still rather esoteric for this crowd, considering we still haven't nailed down the concept of a distance, yet.

 

[Polymath257]

So are you telling me, that if I was somehow able to ride like a jockey on a photon. What is for us about an 8 min. 20 second trip from the Sun to the Earth, would be no different than a trip 8 million ly away. I would see no difference in the time or the distance I traveled.

Well, massive objects cannot move at the speed of light, so there is a fundamental problem with your question.

Once again, there is no valid reference frame that moves at the speed of light. So it is problematic to talk about what light 'experiences'.

Let's do it simply. Suppose you see a bar of length L. Someone going past you at the velocity c will see a bar of length L*sqrt(1-(v/c)^2 ).

As v-->c, the length of the bar goes to 0. In other words, the distance light has to travel goes to 0.

Now, suppose you see light take time T to go the distance L. So, L=T*c.

Then the observer moving past you at velocity v will seee the time for light to go that distance to be T*sqrt(1-(v/c)^2 ).

As v-->c, this time also goes to 0. In other words, the time it takes light to travel goes to 0.

But, the speed of light as determined by that observer going past you at velocity v will be [ L*sqrt(1-(v/c)^2 ) ]/[ T*sqrt(1-(v/c)^2 ) ] = L/T =c.

So as v-->c , this speed is c.

 

[Kangaroo Feathers]

So are you telling me, that if I was somehow able to ride like a jockey on a photon. What is for us about an 8 min. 20 second trip from the Sun to the Earth, would be no different than a trip 8 million ly away. I would see no difference in the time or the distance I traveled.

yes.

Once again, relativistic physics does not fit nicely into our non-relativistic brains.

 

[Subduction Zone]

That photons were present and possible during the "Universal Dark Age", their diffusion wasn't which is why we can't detect their echos now. Still rather esoteric for this crowd, considering we still haven't nailed down the concept of a distance, yet.

I don't think that @Sustainer will ever allow himself to learn. Side discussions will occur under these circumstances.

 

[Subduction Zone]

No. The limit is c because as time goes to 0, so does distance. At each speed under c, the quotient is c. So the limit is c.

I don't think that either of our deniers understands the concept of a mathematical limit. To you and me it is "high school math". Sadly most in the U.S. never take this sort of math course.

 

[Polymath257]

I don't think that either of our deniers understands the concept of a mathematical limit. To you and me it is "high school math". Sadly most in the U.S. never take this sort of math course.

I try to do what I can.

 

[Subduction Zone]

I try to do what I can.

Me too. Though when people run into an idea that they do not like and declare it "wrong" without even listening to why we know that the old ideas were shown to be in error a long time ago I can get a bit short with them.

 

[BilliardsBall]

I see, so non-skeptics have some magical abilities skeptics do not? Care to elucidate them and explain why these abilities are reliable?

Open-mindedness. According to the scriptures, all sincere truth seekers find Jesus and are set free from certain burdens and biases.

Hallejujah!

 

[BilliardsBall]

A fish that could speak and reason could be told about the water and it could be demonstrated to such a fish.

Non-skeptics tell skeptics about deities but can't actually demonstrate such things exist.

Skeptics are different than fish who speak, since they are closed-minded.

 

[Polymath257]

Skeptics are different than fish who speak, since they are closed-minded.

On the contrary, they are just not so open minded their brains fall out.

 

[Subduction Zone]

Skeptics are different than fish who speak, since they are closed-minded.

Oh my!! You have that backwards, as usual.

 

[Thermos aquaticus]

Hi Thermos aquaticus,

I think even what you have shown with the definition for the meter kind of proves one of my points.

Even after they defined the meter using the speed of light. When you state the distance in meters , it tells you nothing about the time involved for the light to get here. That is without doing math.
Yet when you state the distance in light years, you inherently know the time involved. That was what I meant when I said it is a distance, but time (for light) is built in to it.

Time is built into the reference used for the distance. It is no difference than knowing 1 cubic centimeter of water has a mass of one gram even though one cubic centimeter of every other liquid will have a different mass. References are built into all the distances we use.

 

[Thermos aquaticus]

If light reaches it's destination instantly from the point of view of the photon, then why does it take light over 8 minutes to get here from the Sun?

Time dilation due to high velocities. It's a part of the theory of relativity.

But then again how can it even get here, since you say it doesn't go any distance?

That would be length contraction due to high velocities, also a part of the theory of relativity.

 

[gnostic]

Sustainer. You are confusing “year” with “light year”.

They are not the same things.

The term “year” is a measure of time, but the term “light year” is a measure of distance.

light year

a unit of length in astronomy equal to the distance that light travels in one year in a vacuum or about 5.88 trillion miles (9.46 trillion kilometers)

light year

Astronomy

• 1 A unit of astronomical distance equivalent to the distance that light travels in one year, which is 9.4607 × 10¹² km (nearly 6 million million miles).
  

light year

(astronomy) A unit of length (abbreviation ly; equal to just under 10 trillion kilometres (10^16 metres)) equal to the distance light travels in one Julian year; used to measure extremely large distances.

light year

Light-year, in astronomy, the distance traveled by light moving in a vacuum in the course of one year, at its accepted velocity of 299,792,458 metres per second (186,282 miles per second). A light-year equals about 9.46073 × 10^12 km (5.87863 × 10^12 miles), or 63,241 astronomical units. About 3.262 light-years equal one parsec.

Do you not the see common denominators for each of these definitions to “light year”???

The unit type for light year is “length” or “distance”, and the units used in conversions are given in kilometres, miles or astronomical units, not time.

You seriously have comprehension problems.

If you look up any physics and astronomy books, the units given are always distance, not time.

 

[Thermos aquaticus]

You are stuck thinking time doesn't exist at the speed of light. There is no proof/evidence of that.

There is evidence. The theory of relativity has been tested, and it makes accurate predictions. One of the best examples is the Hafele-Keating experiment which demonstrated time dilation for both gravitational fields and differences in velocity.

Hafele–Keating experiment - Wikipedia

They synced up several atomic clocks and kept some of them on Earth and sent some of them on airplanes that flew at altitude in opposite directions. When they brought the clocks back together they were no longer in sync because the clocks experienced time ticking at different rates due to their altitude and relative velocities. These differences were consistent with the predictions made by the theory of relativity, the same theory that tells us that time and distance do not exist in the photon's frame of reference.

Here is another thought experiment you may want to think about. You are travelling at 50% of the speed of light in a spacecraft approaching Earth. You turn a light on at the front of the spaceship and it shines towards Earth. What speed will you measure for the speed of the light exiting your ship, and what will people on Earth measure for the speed of that same light beam?