Physics Help Forum How to convert time into space?

 Special and General Relativity Special and General Relativity Physics Help Forum

 Jun 25th 2017, 10:17 PM #1 Senior Member   Join Date: Feb 2017 Posts: 164 How to convert time into space? I was reading the proof of E=MC2. In one article it was mentioned that time can be converted to space. So time after conversion would be 300000. so speed of light c= distance/time. Now space that is the distance is 300000 and after conversion time is also 300000. So 300000/300000 we get c=1. So c2 is also equal to 1. So it follows that E=M. But my question is how can time be converted to space? i.e how can time of 1 second be converted to space of 300000? Why does time convert to space? Last edited by avito009; Jun 25th 2017 at 10:20 PM.
 Jun 25th 2017, 11:07 PM #2 Senior Member   Join Date: Feb 2017 Posts: 164 Conversion factor C or speed of light is nothing but a conversion factor. Just like there is a conversion factor between meters and miles which is .0006214, there is one between seconds and meters. 1 second = 300000000 m/s. So 2 seconds be= 600000000 m/s. Last edited by avito009; Jun 25th 2017 at 11:12 PM.
 Jun 26th 2017, 03:28 PM #3 Senior Member   Join Date: Nov 2013 Location: New Zealand Posts: 534 It's more that that one spatial axis and the time axis are rotated into each other, not really space becoming time. Not sure if you're ready for the maths but the basic ideas put forth by this video are good.
 Jun 26th 2017, 05:09 PM #4 Forum Admin     Join Date: Apr 2008 Location: On the dance floor, baby! Posts: 2,169 Another interesting by-way: Look up Wick rotation. (The Wiki page says the article needs some work but it looks okay enough.) Essentially we take the 0th component of the event and create a new "time coordinate" which is equal to $\displaystyle x_0$ --> $\displaystyle x_4 = i x_0$. Then you have a more or less Euclidean four-space, though one of the coordinates is imaginary. -Dan kavinmathi likes this. __________________ Do not meddle in the affairs of dragons for you are crunchy and taste good with ketchup. See the forum rules here.
Jun 28th 2017, 10:25 PM   #5
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 Originally Posted by avito009 I was reading the proof of E=MC2. In one article it was mentioned that time can be converted to space.
Time cannot be converted into space anymore than energy can be converted into mass.

The expression E = mc^2 does not mean that mass can be converted into mass. It means that if you have an amount of mass m there is a maximum about of energy E which can result from conversions taking place in the matter. E.g. if a ball of putt absorbs an amount of radiation having an energy E the mass of the putty will increase by the amount m.

In the case of spacetime transformations the spacetime coordinates (x,y,z,t) denote the coordinates of an event, i.e. a place and a time. E.g. a firecracker explodes at the location (x, y, z) at the time t. If this is observed in another frame of reference then the coordinates of the event will be different. That mans that it will happen at a different spatial location at a different time.

 Jun 30th 2017, 09:13 AM #6 Senior Member     Join Date: Jun 2016 Location: England Posts: 377 In cosmology it is often convenient to talk about distance in terms of time: a light-year for example, being the distance travelled by light in a year. Light-minutes and light-seconds are also used (the sun is about 9 light-minutes away, the moon about 3 light-seconds) It is similarly possible to swap this around and talk about time in terms of distance and the speed of light. Thus (for example) a light-metre would be the time taken for light to travel 1 meter (a very short, but measureable, time). When working in 4 dimensional space-time mathematics, it is often convenient to express all 4 dimensional quantities in terms of their relationship to the speed of light. __________________ ~\o/~
Jul 2nd 2017, 10:43 AM   #7
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 Originally Posted by Woody In cosmology it is often convenient to talk about distance in terms of time: a light-year for example, being the distance travelled by light in a year. Light-minutes and light-seconds are also used (the sun is about 9 light-minutes away, the moon about 3 light-seconds) It is similarly possible to swap this around and talk about time in terms of distance and the speed of light. Thus (for example) a light-metre would be the time taken for light to travel 1 meter (a very short, but measureable, time). When working in 4 dimensional space-time mathematics, it is often convenient to express all 4 dimensional quantities in terms of their relationship to the speed of light.
Please don't confuse the name of the unit of distance with the fact that it is a unit of distance. So its not specifically talking about distance in terms of time but rather its a convenient unit because one can imagine how far ligh travels in a year.

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