# Speed of light? or higher question **URL:** \ **Category:** Factual Questions\ **Created:** [March 22, 2015, 10:38pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719 "2015-03-22T22:38:17Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![virtually\_yours](https://avatars.discourse-cdn.com/v4/letter/v/a587f6/32.png) [@virtually\_yours](https://boards.straightdope.com/u/virtually_yours)\ **Post date:** [March 24, 2015, 8:18pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/21 "2015-03-24T20:18:42Z")
The answer I got was this: _The speed of light in a vacuum © is exactly 299,792,458 m/s. What you’ve described is a time dilation factor of 18,262,125:1, which will require traveling at very nearly c. In fact, the answer is so close to c that you’ll need a better-than-average calculator to be able to calculate the difference._ The minute I mentioned the Quran all that changed. hmmm Virtually yours, Virtually Yours ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [March 24, 2015, 8:21pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/22 "2015-03-24T20:21:17Z")
> [@virtually\_yours](#): > > The minute I mentioned the Quran all that changed. Nothing changed, other than you demonstrating that you didn’t understand the answer you got. ---
**Author:** ![virtually\_yours](https://avatars.discourse-cdn.com/v4/letter/v/a587f6/32.png) [@virtually\_yours](https://boards.straightdope.com/u/virtually_yours)\ **Post date:** [March 24, 2015, 8:24pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/23 "2015-03-24T20:24:01Z")
> [@Telemark](#): > > Nothing changed, other than you demonstrating that you didn’t understand the answer you got. You don’t think I understand this:?? What you’ve described is a time dilation factor of 18,262,125:1, which will require traveling at very nearly c. In fact, the answer is so close to c that you’ll need a better-than-average calculator to be able to calculate the difference.\* Virtually yours, Virtually Yours ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [March 24, 2015, 8:46pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/24 "2015-03-24T20:46:51Z")
> [@virtually\_yours](#): > > You don’t think I understand this:?? > > What you’ve described is a time dilation factor of 18,262,125:1, which will require traveling at very nearly c. In fact, the answer is so close to c that you’ll need a better-than-average calculator to be able to calculate the difference.\* I’m sure you understood that bit. But you also need to understand these bits: > [@leahcim](#): > > It would work for any number between 1 and infinity and > [@naita](#): > > For instance if the phrase was to Him in a Day the measure whereof is a fortnight, we’d get 99 % of the speed of light. Almost any number you put in spits out a figure close enough to the speed of light for it to look notable. But since you can pick any number, it obviously isn’t any kind of prediction. That’s relativity for you. To get a decent amount of time dilation, you have to get up to a travel speed pretty darn close to c. But to get a _whole lot more_ time dilation, your travel speed, while faster, can still be described as “pretty darn close to c”. It doesn’t scale in an intuitive way. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 24, 2015, 8:52pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/25 "2015-03-24T20:52:44Z")
It’s just math. Plug in a number higher than 50,000 and you’ll get a number even closer to the speed of light. As the numbers of years approaches infinity, the speed necessary to travel approaches the speed of light. There is nothing remarkable about this. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [March 24, 2015, 8:55pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/26 "2015-03-24T20:55:47Z")
> [@virtually\_yours](#): > > The answer I got was this: > _The speed of light in a vacuum (c) is exactly 299,792,458 m/s. What you’ve described is a time dilation factor of 18,262,125:1, which will require traveling at very nearly c. In fact, the answer is so close to c that you’ll need a better-than-average calculator to be able to calculate the difference._ > > The minute I mentioned the Quran all that changed. > hmmm > Virtually yours, Virtually Yours Ask the same question for a day’s travel equating to 100,000 or 500,000 years and you will still get the same answer (‘very close to the speed of light’) ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [March 24, 2015, 9:02pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/27 "2015-03-24T21:02:57Z")
> [@pulykamell](#): > > As the numbers of years approaches infinity, the speed necessary to travel approaches the speed of light. There is nothing remarkable about this. Well, I’d say it’s remarkable. Just not in the way the OP seems to think. 😉 ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [March 24, 2015, 9:09pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/28 "2015-03-24T21:09:21Z")
> [@Martian Bigfoot](#): > > Almost any number you put in spits out a figure close enough to the speed of light for it to look notable. But since you can pick any number, it obviously isn’t any kind of prediction. To be fair, if the quote was “The angels and the Rûh ascend to Him in a Day the measure whereof is a day and fifteen minutes” the derived number would not be close to the speed of light (although it would still be quite fast in a human scale). The more important thing is the “prediction” only works because we _already know_ the speed of light. If we thought, incorrectly, that the speed of light was 500000 km/s, the methodology would find a speed ridiculously close to 500000 km/s. A prediction that you have to know the answer already to interpret is no prediction at all. ---
**Author:** ![virtually\_yours](https://avatars.discourse-cdn.com/v4/letter/v/a587f6/32.png) [@virtually\_yours](https://boards.straightdope.com/u/virtually_yours)\ **Post date:** [March 24, 2015, 9:16pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/29 "2015-03-24T21:16:58Z")
> [@Martian Bigfoot](#): > > I’m sure you understood that bit. But you also need to understand these bits: > > and > > Almost any number you put in spits out a figure close enough to the speed of light for it to look notable. But since you can pick any number, it obviously isn’t any kind of prediction. > > That’s relativity for you. To get a decent amount of time dilation, you have to get up to a travel speed pretty darn close to c. But to get a _whole lot more_ time dilation, your travel speed, while faster, can still be described as “pretty darn close to c”. It doesn’t scale in an intuitive way. Yes I understand that you say any number works, but someone somehow said this with a number or two 1400 years ago or more. Islam teaches that the angels were made from light, and science has shown that very near to the speed of light can be obtained but not the exact speed. So to me it was a surprise to find out that what was said in the Quran seems to work out to almost the speed of light. I actually was thinking it would get in to theoretical faster speeds of light, but like I said was pleasantly surprised to see that it actually almost comes to the speed of light, according to what I understand what was answered here That’s all I am saying. Yes any number might work as you say, but 1400 years ago it was basically defined Virtually yours, Virtually Yours. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [March 24, 2015, 9:20pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/30 "2015-03-24T21:20:27Z")
> [@virtually\_yours](#): > > Yes any number might work as you say, but 1400 years ago it was basically defined > Virtually yours, Virtually Yours. No, it wasn’t. You have to already know the speed of light to get the answer. The Koran did not predict the speed of light. The speed of light, as determined through centuries of experiment, allows one to reinterpret the Koran as if it were talking about relativity, which the Koran also didn’t predict. Einstein did. ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [March 24, 2015, 9:34pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/31 "2015-03-24T21:34:04Z")
> [@virtually\_yours](#): > > I actually was thinking it would get in to theoretical faster speeds of light Well, there is no number you can pick that will give you an answer faster than the speed of light. None. Does not exist on the number line. As you pick numbers closer and closer to infinity, you only get answers that snuggle up closer and closer to the speed of light. And has been repeated several times now: 1. _Any number you pick (well, bigger than about a fortnight) will look impressive._ I hope you understand why this means that 50,000 doesn’t mean anything special in this context. 2. _To do the math in the first place, you already need a value for c._ We could have a mistaken value for c, and doing the calculation would still spit out a number close to that mistaken value. The actual value of c has been measured by careful experiments. There is nothing in the quote that predicts the value. ---
**Author:** ![sbunny8](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@sbunny8](https://boards.straightdope.com/u/sbunny8)\ **Post date:** [March 24, 2015, 9:36pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/32 "2015-03-24T21:36:18Z")
> [@virtually\_yours](#): > > Yes I understand that you say any number works, but someone somehow said this with a number or two 1400 years ago or more. > Islam teaches that the angels were made from light, and science has shown that very near to the speed of light can be obtained but not the exact speed. So to me it was a surprise to find out that what was said in the Quran seems to work out to almost the speed of light. > I actually was thinking it would get in to theoretical faster speeds of light, but like I said was pleasantly surprised to see that it actually almost comes to the speed of light, according to what I understand what was answered here > That’s all I am saying. > Yes any number might work as you say, but 1400 years ago it was basically defined > Virtually yours, Virtually Yours. No, you still aren’t getting it. When you travel at 95% of c, or 99% of c, or 99.7% of c, or 99.99993% of c, time slows down for you and the exact time dilation factor can be calculated with a formula. But when we’re talking about large time dilation factors, like 100:1 or 1000:1 or 1000000:1 or 1000000000:1 you get pretty much the exact same answer, that you’d be traveling almost, but not quite, at c. Knowing this bit of trivia tells you absolutely nothing about how big c is. And whether you said “one day equals a hundred years” or “one day equals 5,000 years” or “one day equals a million years” the speed required would be pretty much identical: almost, but not quite, at c. None of this has anything to do with actually measuring c. Now, if the Koran has said that the a beam of light can go to The Moon and back 30,000 times in one day, then I’d be impressed, because that would actually say something about how fast c is (relative to the distance to the Moon, anyway). ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [March 24, 2015, 9:37pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/33 "2015-03-24T21:37:12Z")
> [@virtually\_yours](#): > > Yes any number might work as you say, but 1400 years ago it was basically defined Only if you change the definition of the word “defined.” ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [March 24, 2015, 9:43pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/34 "2015-03-24T21:43:31Z")
And, look, we’re not dissing the Quran or anything (at least I’m not). It is plenty interesting and can be discussed at length. It does a number of impressive things. Predicting the speed of light, however, just happens to not be one of them. Sorry about that, but it’s just how it goes. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [March 24, 2015, 11:46pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/35 "2015-03-24T23:46:22Z")
> [@virtually\_yours](#): > > Yes I understand that you say any number works, but someone somehow said this with a number or two 1400 years ago or more. > Islam teaches that the angels were made from light, and science has shown that very near to the speed of light can be obtained but not the exact speed. So to me it was a surprise to find out that what was said in the Quran seems to work out to almost the speed of light. > I actually was thinking it would get in to theoretical faster speeds of light, but like I said was pleasantly surprised to see that it actually almost comes to the speed of light, according to what I understand what was answered here > That’s all I am saying. > Yes any number might work as you say, but 1400 years ago it was basically defined > Virtually yours, Virtually Yours. Why are you ignoring the fact that the same faulty argument shows that the New Testament defined the speed of light on the same bogus way, 600 years before the Koran? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 25, 2015, 1:55am UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/36 "2015-03-25T01:55:10Z")
It’s also a huge error. Yeah, 99.99999999999985007730442166452766531951946% of c might look awfully close to c to us mere mortals, but if you actually take the difference between the two speeds, you’ll find that you’re off by 100%: c - 99.99999999999985007730442166452766531951946% of c = c. ---
**Author:** ![Mosier](https://avatars.discourse-cdn.com/v4/letter/m/7ea924/32.png) [@Mosier](https://boards.straightdope.com/u/Mosier)\ **Post date:** [March 25, 2015, 4:45am UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/37 "2015-03-25T04:45:40Z")
1 day equals 50 billion years would be a more accurate prediction. 1 day equals 200 trillion years would be more accurate still. 1 day equals 50,000 years is actually a piss-poor prediction of the speed of light, if all possible numbers are considered. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [March 25, 2015, 6:13am UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/38 "2015-03-25T06:13:29Z")
> [@Mosier](#): > > 1 day equals 50 billion years would be a more accurate prediction. 1 day equals 200 trillion years would be more accurate still. 1 day equals 50,000 years is actually a piss-poor prediction of the speed of light, if all possible numbers are considered. Since none of them do any prediction, you’re only clouding the issue. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [March 25, 2015, 12:46pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/39 "2015-03-25T12:46:50Z")
I’m also have a problem imagining the logistics of the situation. Assuming that the Earth and God are more-or-less at rest relative to each other, then it must mean that the angels experience a day while Earth experiences 50000 years. If this event started around the time of the founding of Islam, then the angels should still be in the middle of doing it (and could presumably be picked up by suitably powerful telescopes). And God must be more-or-less 50000 light-years away. The alternative, that Earth experienced a day while the angels experienced 50000 years can only make sense if God is moving at quite a clip relative to Earth (and the calculation is done in God’s reference frame) and the angels have to really accelerate to catch up. So basically we have either “God is very distant from Earth” or “God is actively running away from Earth”, which don’t seem like intended tenets of any God-centred religion. Or the writer was just being a little poetic. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [March 25, 2015, 12:59pm UTC](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719/40 "2015-03-25T12:59:32Z")
> [@leahcim](#): > > I’m also have a problem imagining the logistics of the situation. Assuming that the Earth and God are more-or-less at rest relative to each other, then it must mean that the angels experience a day while Earth experiences 50000 years. If this event started around the time of the founding of Islam, then the angels should still be in the middle of doing it (and could presumably be picked up by suitably powerful telescopes). And God must be more-or-less 50000 light-years away. > > The alternative, that Earth experienced a day while the angels experienced 50000 years can only make sense if God is moving at quite a clip relative to Earth (and the calculation is done in God’s reference frame) and the angels have to really accelerate to catch up. > > So basically we have either “God is very distant from Earth” or “God is actively running away from Earth”, which don’t seem like intended tenets of any God-centred religion. Or the writer was just being a little poetic. You get the same effect travelling a curved path. Like a powered orbit. Takes a lot of energy though. Maybe that’s what really fueling the Sun? Waste heat from tightly orbiting angels. [Previous page](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719.md?page=1) [Next page](https://boards.straightdope.com/t/speed-of-light-or-higher-question/715719.md?page=3)