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ATOT Physics Dept: How old are photons?

SphinxnihpS

SphinxnihpS

Diamond Member
The Universe is approximately 14 billion years old. About 400,000 after the Big Bang, the first light appeared. We have seen and measured this light. It is the Cosmic Microwave Background Radiation. It has been traveling to us for nearly 14 billion years at the speed of light.

So, since time slows down the faster something goes, and these things are going as fast as things can go, how old are they within their own frame of reference? Are they 14 billion years old? Are they 0?

In Cosmos, Carl Sagan said that at speeds approaching the speed of light, we could circumnavigate the known universe in "some 56 years". What's the math?
 
SphinxnihpS said:
So, since time slows down the faster something goes, and these things are going as fast as things can go, how old are they within their own frame of reference? Are they 14 billion years old? Are they 0?
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More or less this. The photon has essentially not experienced time yet,. Though that's sort of a funny thing to say, since the photon does not experience anything at all without fundamentally changing what it is.
 
crashtestdummy said:
More or less this. The photon has essentially not experienced time yet,. Though that's sort of a funny thing to say, since the photon does not experience anything at all without fundamentally changing what it is.
Click to expand...

Yeah, I'd like the formula so that I can figure out the time dilation for any speed.
 
SphinxnihpS said:
The Universe is approximately 14 billion years old. About 400,000 after the Big Bang, the first light appeared. We have seen and measured this light. It is the Cosmic Microwave Background Radiation. It has been traveling to us for nearly 14 billion years at the speed of light.

So, since time slows down the faster something goes, and these things are going as fast as things can go, how old are they within their own frame of reference? Are they 14 billion years old? Are they 0?

In Cosmos, Carl Sagan said that at speeds approaching the speed of light, we could circumnavigate the known universe in "some 56 years". What's the math?
Click to expand...

Whachoo talkin bout, Willis? The universe is only about 6,000 years old. Everyone knows this.
 
Neil DeGrasse Tyson did a podcast on this subject just last month. This is what relativity is all about. Depends on the point of reference. As you approach the speed of light, time slows. At light speed, time stops. From the photon's perspective the time it takes from when it's emitted to when it hits something happens instantly. Form our perspective it takes could take millions of years.

It's also theoretically possible to reverse time if you can go past light's maximum speed. It's one of those things that works on paper. The tachyon is a proposed particle that would be capable of this.
 
SphinxnihpS said:
The Universe is approximately 14 billion years old. About 400,000 after the Big Bang, the first light appeared. We have seen and measured this light. It is the Cosmic Microwave Background Radiation. It has been traveling to us for nearly 14 billion years at the speed of light.

So, since time slows down the faster something goes, and these things are going as fast as things can go, how old are they within their own frame of reference? Are they 14 billion years old? Are they 0?

In Cosmos, Carl Sagan said that at speeds approaching the speed of light, we could circumnavigate the known universe in "some 56 years". What's the math?
Click to expand...

DrPizza said:
In whose frame of reference?
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:whiste:
 
Paul98 said:
A photon doesn't have an inertial frame of reference.
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Is that because

befdade8ef36cc1c0e07b5493ad94412.png


is undefined or infinite for v=c? The Lorentz factor is 1/0.

In physics, the Lorentz transformation (or transformations) is named after the Dutch physicist Hendrik Lorentz. It was the result of attempts by Lorentz and others to explain how the speed of light was observed to be independent of the reference frame, and to understand the symmetries of the laws of electromagnetism. The Lorentz transformation is in accordance with special relativity, but was derived well before special relativity.
Click to expand...
from: https://en.wikipedia.org/wiki/Lorentz_transformation
 
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I would guess most photons live very short lives, basically the time it takes for light to reach it's destination from the source, then they are converted to heat. Then again there are stars that are many light years away, so those photons would be older depending on how long before they hit an obstacle such as dust or bigger solids. Though I'm no physicist so I could be way off here.
 
light is IMO inherently transdimensional in nature and a "bridge particle" through which humans will eventually discover the dimensions above time... skimming the laws of both in order to be able to do what it does.
 
Red Squirrel said:
I would guess most photons live very short lives . . . .
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Incorrect. inside the sun (and thus other stars) photons bounce around for millions to billions of years in their slow and very chaotic journey to and out of the sun's edge. Light generated though other forms (verymuch the minority to put it lightly) can have a far shorter existence time, though. Like the light that is enabling you to read what I typed here.
 
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