# Speed of light

#### benben

##### Active member
I've really enjoyed listening to the recent RSR programs on the speed of light. As a YEC the light-time travel problem is one that's fascinated and stumped me for years.

A while ago I read one of Lisle's books wherein he proposed the ASC (infinite one-way speed of light convention). I liked the idea, but something about it never felt right. After thinking through this again I've concluded that the one-way speed of light can't be infinite.

If the one-way speed of light in a given direction is truly instantaneous, then no time passes during which light traverses a given distance. To put it another way, the same light (i.e. photon) is in two places at once. Only God can be in multiple places at once, so the idea that a photon can also is a problem.

There's also a fascinating implication of a photon being in two places at once. When light is bounced off a mirror, the initial photon of light would pop into existence at the source AND be reflected off the mirror at exactly the same moment. Sounds cool, but again, none of this makes sense.

And there's another problem. The equation for speed is speed = distance / time. Therefore, a speed of infinity would require time to be 0 (infinity = distance / 0). But division by zero leads to absurd and clearly false expressions like 0=1.

To illustrate this, let's say that on a one-way trip, light travels 100,000 miles in an instant. Therefore infinity = 100,000 miles / 0. Multiply both sides of the equation by 0, and you get 0 miles = 100,000 miles. You can do this with any distance and will always get 0 = whatever distance you use.

Of course, we can get around these problems by saying that the one-way speed of light in one direction is some real number so fantastically large that it might as well be infinity. However, the idea of the speed of light being different in different directions seems counterintuitive, like the results of the double-slit experiment but much weirder. That alone isn't a reason to dismiss it, but it raises a number of even more difficult questions such as how light "knows" what direction it's going or whether it's being measured on the return trip.

Anyway, change my mind

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#### Derf

##### Well-known member
I've really enjoyed listening to the recent RSR programs on the speed of light. As a YEC the light-time travel problem is one that's fascinated and stumped me for years.

A while ago I read one of Lisle's books wherein he proposed the ASC (infinite one-way speed of light convention). I liked the idea, but something about it never felt right. After thinking through this again I've concluded that the one-way speed of light can't be infinite.

If the one-way speed of light in a given direction is truly instantaneous, then no time passes during which light traverses a given distance. To put it another way, the same light (i.e. photon) is in two places at once. Only God can be in multiple places at once, so the idea that a photon can also is a problem.

There's also a fascinating implication of a photon being in two places at once. When light is bounced off a mirror, the initial photon of light would pop into existence at the source AND be reflected off the mirror at exactly the same moment. Sounds cool, but again, none of this makes sense.

And there's another problem. The equation for speed is speed = distance / time. Therefore, a speed of infinity would require time to be 0 (infinity = distance / 0). But division by zero leads to absurd and clearly false expressions like 0=1.

To illustrate this, let's say that on a one-way trip, light travels 100,000 miles in an instant. Therefore infinity = 100 miles / 0. Multiply both sides of the equation by 0, and you get 0 miles = 100,000 miles. You can do this with any distance and will always get 0 = whatever distance you use.

Of course, we can get around these problems by saying that the one-way speed of light in one direction is some real number so fantastically large that it might as well be infinity. However, the idea of the speed of light being different in different directions seems counterintuitive, like the results of the double-slit experiment but much weirder. That alone isn't a reason to dismiss it, but it raises a number of even more difficult questions such as how light "knows" what direction it's going or whether it's being measured on the return trip.

Anyway, change my mind
I had the same reaction you did when I first heard Lisle speak about it. And I think I heard RSR say they don’t endorse the idea.

To me it’s like you’re trying to define away the problem.

If we’re going to go that direction, I much prefer a speed of light component of quantum mechanics that says the speed of light is only finite when someone witnesses it, but otherwise it’s infinite.

#### benben

##### Active member
I had the same reaction you did when I first heard Lisle speak about it. And I think I heard RSR say they don’t endorse the idea.

To me it’s like you’re trying to define away the problem.

If we’re going to go that direction, I much prefer a speed of light component of quantum mechanics that says the speed of light is only finite when someone witnesses it, but otherwise it’s infinite.
Yeah, I think it's easy to oversimplify measuring the speed of light and try to use the same paradigms we use to measure the speed of other things. But all speed measurements of other things depend on the speed of light being so much faster than the things we're measuring. For example, measuring the speed of a bullet with a high speed camera is trivial because the light bouncing off the bullet is so much faster than the bullet itself.

But now we want to measure light, and the problem is that nothing is faster than light. We can "slow light down" in a sense by passing it through a murky solution, but once that light is refracted, it travels at its normal speed. So however we measure it, we always observe light traveling no faster than speed c.

As far as the light-time travel problem goes, my understanding also is that Bob and Fred do not buy the ASC. I think it makes more sense to believe that God either sped up light during creation or just created it already in place. This would fit with the rest of creation, wherein God created Adam and the animals fully grown, rater than as babies.

#### JudgeRightly

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As far as the light-time travel problem goes, my understanding also is that Bob and Fred do not buy the ASC. I think it makes more sense to believe that God either sped up light during creation or just created it already in place. This would fit with the rest of creation, wherein God created Adam and the animals fully grown, rater than as babies.

#### Derf

##### Well-known member
This would fit with the rest of creation, wherein God created Adam and the animals fully grown, rater than as babies.
The analogy to light being created in place would be if God created Adam with memories of events that never happened. Like his three-year-old birthday party with Grandma baking a cake, and his daddy with the video camera.

#### benben

##### Active member
The analogy to light being created in place would be if God created Adam with memories of events that never happened. Like his three-year-old birthday party with Grandma baking a cake, and his daddy with the video camera.

I think that analogy is flawed. Light appearing to be from a star that actually exists is unlike false memories of events that never happened. The difference being that there's no deception wrought by creating the light in place, just as there would be no deception by speeding up the light. The light makes it appear as if a star exists, and it does.

#### Yorzhik

##### Well-known member
Hall of Fame
Not knowing how God created the stars to be seen certainly has some great philosophical impacts. Is it considered deception if God creates the light events of distant stars, some of those events being of the star at the end of its burning cycle? or an object passing in front of a star that would change the light we would see on a star over 10000 light years away? Perhaps it would depend on how God viewed it.

Perhaps going into the past is impossible, but going into the future isn't so God just set the stars into the future.

Perhaps modeling, since all material is just information anyway, at a super-sped up rate would allow God to get the light to earth in the time allotted. The "sped-up" modeling reminds me of a computer program I once ran where you could travel around a 3-D version of the solar system. If you set the travel speed to light speed, you'd be surprised how slow light speed is when traveling from planet to planet. So they let you speed up travel time.

Perhaps the Russel Humphreys idea is correct that the rest of the universe outside the solar system is old via the theory of relativity.

Perhaps the stars are just old, and God just views it as a minor discrepancy that doesn't matter.

Perhaps something I haven't thought of, like ASC, which I've hardly looked into since I've only learned about it this year.

#### Derf

##### Well-known member
I think that analogy is flawed. Light appearing to be from a star that actually exists is unlike false memories of events that never happened. The difference being that there's no deception wrought by creating the light in place, just as there would be no deception by speeding up the light. The light makes it appear as if a star exists, and it does.
I still don't think it works. @Yorzhik mentions it.

Assuming the speed of light has never changed, imagine that we, today, see a supernova from a star that is 100,000 light years away. Yesterday, we could still see the star in it's pre-nova state, looking like a normal star. 6000 years ago, Adam was seeing the star in it's pre-nova state, too.

But according to the star's light, the supernova occurred 93,000 years ago, which was before the star was created, only 6000 years ago. If God created it as a regular star, 6000 years ago, then when did it go supernova? If after that point, then the light would not yet show us, even today, that there was a supernova. If before that point, then the supernova happened to the star before the star was created, and all of the "normal starlight" (pre-supernova) is thus imaginary (not something the star actually experienced, because it happened before it was created) thus is analogous to Adam remembering his grandma at his 3rd birthday party.

Stretching or changing speed of light resolves this issue, but light created in-transit doesn't.

#### JudgeRightly

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Assuming the speed of light has never changed

A poor assumption to make, considering that there is no way to verify it.

#### User Name

##### Greatest poster ever
Banned
If the one-way speed of light in a given direction is truly instantaneous, then no time passes during which light traverses a given distance.
"Photons do not experience time. From the perspective of a photon, there is no such thing as time. It's emitted, and might exist for hundreds of trillions of years, but for the photon, there's zero time elapsed between when it's emitted and when it's absorbed again." - https://phys.org/news/2014-05-does-light-experience-time.html

#### Derf

##### Well-known member
A poor assumption to make, considering that there is no way to verify it.
Yes, but for the example, it was necessary.

#### benben

##### Active member
"Photons do not experience time. From the perspective of a photon, there is no such thing as time. It's emitted, and might exist for hundreds of trillions of years, but for the photon, there's zero time elapsed between when it's emitted and when it's absorbed again." - https://phys.org/news/2014-05-does-light-experience-time.html

This is an example of the unhelpful, vague descriptions pop-sci publications use. The phrase "experience time" is absurdly redundant, for to experience anything requires time. Saying that a photon doesn't "experience time" is the same as saying a photon doesn't exist, which is nuts.

#### benben

##### Active member
I still don't think it works. @Yorzhik mentions it.

Assuming the speed of light has never changed, imagine that we, today, see a supernova from a star that is 100,000 light years away. Yesterday, we could still see the star in it's pre-nova state, looking like a normal star. 6000 years ago, Adam was seeing the star in it's pre-nova state, too.

But according to the star's light, the supernova occurred 93,000 years ago, which was before the star was created, only 6000 years ago. If God created it as a regular star, 6000 years ago, then when did it go supernova? If after that point, then the light would not yet show us, even today, that there was a supernova. If before that point, then the supernova happened to the star before the star was created, and all of the "normal starlight" (pre-supernova) is thus imaginary (not something the star actually experienced, because it happened before it was created) thus is analogous to Adam remembering his grandma at his 3rd birthday party.

Stretching or changing speed of light resolves this issue, but light created in-transit doesn't.

You make some good points. I'm still hesitant about the changing speed of light because as I see it, a changing speed of light would leave gaps of darkness when the speed of light slowed, especially if it slowed abruptly.

#### Bible Believer

##### Member
This is a new section being rolled out to attract people interested in exploring the origins of the universe and the earth from a biblical perspective. Debate is encouraged and opposing viewpoints are welcome to post but certain rules must be followed. 1. No abusive tagging - if abusive tags are found - they will be deleted and disabled by the Admin team 2. No calling the biblical accounts a fable - fairy tale ect. This is a Christian site, so members that participate here must be respectful in their disagreement.
Very refreshing! The group I just was banned from has so many Atheists, and they allowed them to post in ways that completely undermine the Bible. I appreciate you holding the line!

#### Derf

##### Well-known member
You make some good points. I'm still hesitant about the changing speed of light because as I see it, a changing speed of light would leave gaps of darkness when the speed of light slowed, especially if it slowed abruptly.
We know that the speed of light slows down when it hits denser media. It’s slower in water than in air, and slower in air than in vacuum. So there’s no gaps of darkness due to those changes.

I’m not trying to advocate for the speed of light in vacuum (which is the number we usually use for “c”) changing, but I’m not opposed to the idea, either.

I like the idea of time going slower in heavier gravity. I don’t think anyone has made that work in calculations to account for all the billions of years needed for the light from the most distant stars. So stretching seems like a good option to pursue. We don’t have a good physics of stretching to date.

#### JudgeRightly

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Bob and Fred make a brilliant observation about light in this show. Worth a listen.

#### Stripe

Hall of Fame
I've really enjoyed listening to the recent RSR programs on the speed of light. As a YEC the light-time travel problem is one that's fascinated and stumped me for years.

A while ago I read one of Lisle's books wherein he proposed the ASC (infinite one-way speed of light convention). I liked the idea, but something about it never felt right. After thinking through this again I've concluded that the one-way speed of light can't be infinite.

If the one-way speed of light in a given direction is truly instantaneous, then no time passes during which light traverses a given distance. To put it another way, the same light (i.e. photon) is in two places at once. Only God can be in multiple places at once, so the idea that a photon can also is a problem.

There's also a fascinating implication of a photon being in two places at once. When light is bounced off a mirror, the initial photon of light would pop into existence at the source AND be reflected off the mirror at exactly the same moment. Sounds cool, but again, none of this makes sense.

And there's another problem. The equation for speed is speed = distance / time. Therefore, a speed of infinity would require time to be 0 (infinity = distance / 0). But division by zero leads to absurd and clearly false expressions like 0=1.

To illustrate this, let's say that on a one-way trip, light travels 100,000 miles in an instant. Therefore infinity = 100,000 miles / 0. Multiply both sides of the equation by 0, and you get 0 miles = 100,000 miles. You can do this with any distance and will always get 0 = whatever distance you use.

Of course, we can get around these problems by saying that the one-way speed of light in one direction is some real number so fantastically large that it might as well be infinity. However, the idea of the speed of light being different in different directions seems counterintuitive, like the results of the double-slit experiment but much weirder. That alone isn't a reason to dismiss it, but it raises a number of even more difficult questions such as how light "knows" what direction it's going or whether it's being measured on the return trip.

Anyway, change my mind
:banned:

:chuckle:

I share your concerns. I think that the solution to the distant starlight problem might lie in the universe being stretched out after light was created.

However, that theory, too, has problems.

Lon

#### Stripe

Hall of Fame
The other idea is that lightspeed is vastly greater in regions of lower gravity. With us near the center of the universe, the gravity environment tends to increase as light approaches us, thus it is always slowing down.

#### Idolater

##### "Foundation of the World" Dispensationalist χρ
The other idea is that lightspeed is vastly greater in regions of lower gravity. With us near the center of the universe, the gravity environment tends to increase as light approaches us, thus it is always slowing down.
I think that God created the stars and the light that 'comes from' them all at once. Meaning that light 'originating' from stars, was created in place billions of light years away from the stars it putatively 'came from.'

Idunno.

Lon