# How much does a second weigh? **URL:** \ **Category:** Factual Questions\ **Created:** [March 5, 2008, 6:32pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214 "2008-03-05T18:32:13Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 5, 2008, 6:32pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/1 "2008-03-05T18:32:13Z")
Substituting “Distance divided by Time” in the equation "E=MC2 and then solving for "Time = ", how much does a second weigh at sea level? ---
**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 5, 2008, 6:35pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/2 "2008-03-05T18:35:48Z")
[QUOTE=Will Repair] Substituting “Distance divided by Time” in the equation "E=MC2 and then solving for "Time = ", how much does a second weigh at sea level? [/QUOTE] c in E = mc^2 is a fundamental constant. You can’t pick it apart. ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [March 5, 2008, 6:59pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/3 "2008-03-05T18:59:09Z")
[QUOTE=naita] c in E = mc^2 is a fundamental constant. You can’t pick it apart. [/QUOTE] I’m no physicist, but I don’t think that’s the reason. To the OP: the question is nonsense. The equation shows as much because the units on the left side (energy) are also on a “time-squared” basis. For instance, a “joule” is a kilogram_m_m/(sec\*sec). (kilogram times meters squared over seconds squared) Energy is the amount of work done over a period of time, like the constant ‘c’ is a distance travelled over a unit of time. IOW, the “seconds” come out of the equation. ---
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 5, 2008, 7:25pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/4 "2008-03-05T19:25:11Z")
Combine the last two answers- treat C as a constant and then substitute “Kmm/Sec2” for E then solve for seconds. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 5, 2008, 7:27pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/5 "2008-03-05T19:27:05Z")
1 [Joule](http://en.wikipedia.org/wiki/Joule) is defined as 1 kg m[sup]2[/sup] s[sup]-2[/sup]. So I guess you could say 1 second is equal to 1 m kg[sup]1/2[/sup] J[sup]-1/2[/sup]. ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [March 5, 2008, 7:44pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/6 "2008-03-05T19:44:20Z")
You might as well ask “How much does a mile weigh?” A second is 186,000 miles long however. ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [March 5, 2008, 7:59pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/7 "2008-03-05T19:59:41Z")
[QUOTE=Will Repair] Combine the last two answers- treat C as a constant and then substitute “Kmm/Sec2” for E then solve for seconds. [/QUOTE] No, don’t use the two answers. Use mine. The left side of the equation has sec^2 in the denominator; the right side has sec^2 in the denominator. They cancel when you try to solve for “1 second” (unless you want to solve for seconds in terms of “joules” but joules is not a weight. It has time in it.) The speed of light in a vacuum is a constant, but it still has units, and the units are meaningful. seconds is a measure of time. you can ask “if I use 5 joules of energy, how much mass can I move in one second” but that doesn’t tell you how much “mass” is in a second. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [March 5, 2008, 8:12pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/8 "2008-03-05T20:12:19Z")
Are you folks serious, or is this going to come around to the Henway? ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [March 5, 2008, 8:15pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/9 "2008-03-05T20:15:49Z")
[QUOTE=AskNott] Are you folks serious, or is this going to come around to the Henway? [/QUOTE] _ **PLEEZE** _, don’t anybody ask!!! ---
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 5, 2008, 8:19pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/10 "2008-03-05T20:19:32Z")
[QUOTE=Trunk] “if I use 5 joules of energy, how much mass can I move in one second” [/QUOTE] So you’re saying seconds have a proportional amount of mass and energy, that if seconds have such and such mass they also have to have a certain amount of energy? ---
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 5, 2008, 8:27pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/11 "2008-03-05T20:27:49Z")
[QUOTE=AskNott] Are you folks serious, or is this going to come around to the Henway? [/QUOTE] I’m serious. I can understand that something traveling at the speed of light has /0 mass and is mathematically meaningless, well except for photons, but is solving for seconds as a unit of mass yield a result, even if it is one not easily understood? ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [March 5, 2008, 8:36pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/12 "2008-03-05T20:36:35Z")
A second is a DISTANCE in spacetime. Distances don’t have mass. As I said above, it’s equivalent to asking “How much does a mile weigh?” ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 5, 2008, 8:42pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/13 "2008-03-05T20:42:30Z")
[QUOTE=Will Repair] … is solving for seconds as a unit of mass yield a result, even if it is one not easily understood? [/QUOTE] You can’t describe the second using only the unit of mass. ---
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 5, 2008, 8:53pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/14 "2008-03-05T20:53:41Z")
[QUOTE=Pochacco] A second is a DISTANCE in spacetime. Distances don’t have mass. As I said above, it’s equivalent to asking “How much does a mile weigh?” [/QUOTE] Mass doesn’t have weight until you get within a certain **distance** to another mass! So a mile can be expressed as a relationship between two masses for a given weight, right? ---
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 5, 2008, 8:55pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/15 "2008-03-05T20:55:03Z")
[QUOTE=scr4] You can’t describe the second using only the unit of mass. [/QUOTE] But we can describe it using a proportion of mass and energy? or mass and energy and distance? ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [March 5, 2008, 8:56pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/16 "2008-03-05T20:56:33Z")
[QUOTE=Will Repair] So you’re saying seconds have a proportional amount of mass and energy, that if seconds have such and such mass they also have to have a certain amount of energy? [/QUOTE] No, energy has seconds in it. Simply put (but not perfectly accurate) energy is how much mass is moved in a second. If I tell you A) how much energy and mass I used, you can tell me the second B) how much mass I moved in a second, you can tell me the energy C) how much energy I used in a second, you can tell me the mass Energy is an expression of how much mass is moved in a second. That doesn’t mean that a second has mass any more than a barbell has time. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [March 5, 2008, 9:30pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/17 "2008-03-05T21:30:02Z")
[QUOTE=panache45] _ **PLEEZE** _, don’t anybody ask!!! [/QUOTE] Why not? What’s snew? 😉 ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [March 5, 2008, 10:25pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/18 "2008-03-05T22:25:43Z")
[QUOTE=Will Repair] Mass doesn’t have weight until you get within a certain **distance** to another mass! So a mile can be expressed as a relationship between two masses for a given weight, right? [/QUOTE] Yes, but when you do that the terms that represent the weight will cancel out, leaving only distance behind: weight = (G \* mass1 \* mass2) / (distance \* distance) Where G is the gravitational constant. distance = squareroot ( G \* mass1 \* mass2 / weight) Looking at the units: distance = squareroot ( newton \* meter \* meter \* kilogram \* kilogram / kilogram \* kilogram \* newton ) The kilograms and newtons cancel out. distance = squareroot (meter \* meter) distance = meter See … no mass or force in the final answer. You can’t use gravitiational attraction to express distance as a weight. Time works the same way. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [March 5, 2008, 11:47pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/19 "2008-03-05T23:47:45Z")
1 s = 4.04x10[sup]35[/sup] kg (Hint: convert everything into [Planck units](http://en.wikipedia.org/wiki/Planck_units).) ---
**Author:** ![aldiboronti](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@aldiboronti](https://boards.straightdope.com/u/aldiboronti)\ **Post date:** [March 5, 2008, 11:48pm UTC](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214/20 "2008-03-05T23:48:00Z")
[QUOTE=Pochacco] Yes, but when you do that the terms that represent the weight will cancel out, leaving only distance behind: weight = (G \* mass1 \* mass2) / (distance \* distance) Where G is the gravitational constant. distance = squareroot ( G \* mass1 \* mass2 / weight) Looking at the units: distance = squareroot ( newton \* meter \* meter \* kilogram \* kilogram / kilogram \* kilogram \* newton ) The kilograms and newtons cancel out. distance = squareroot (meter \* meter) distance = meter See … no mass or force in the final answer. You can’t use gravitiational attraction to express distance as a weight. Time works the same way. [/QUOTE] Quod erat demonstrandum, or, as my old Math teacher used to say, Quite Enough Done. [Next page](https://boards.straightdope.com/t/how-much-does-a-second-weigh/440214.md?page=2)