Time from E=mc^2

I was just playing around with E=mc^2, and rearranged it to get this

t = d/(2c^2)^1/2

t is time
d is distance
c is the speed of light

I got this formula but I have no idea what it is trying to say. Anyone have any ideas ?

Oh yes, I checked how E = mc^2 was derived, and found it was derived from the shrinking factor ie. (1 - v^2/c^2)^1/2

If you have gone zero distance between two objects seen in relative terms to one another, then you have not moved (you are still) and time has not passed. As soon as you start to traverse a distance, a time calculation can be performed. You need more information to say exactly what time is referring to.

I assume this is where some scientists try to claim that if you could actually travel at the speed of light (thus covering the respective distance), you'd start travelling backward in time. It is a rather far-fetched opinion in my opinion.

Google says: 299 792 458 m / s for the speed of light

As you see, light itself has a time component.

If you square light, you have: 89 875 517 873 681 764 m^2/s^2

Mass is probably in kilograms (kg=1000 grams), so: E = kg * m^2/s^2

So energy has a time component, as does light. Mass does not. Distance does not.

What else do you want to know?

Edit for clarification:
E = energy
c = speed of light
m = mass (in E = mc^2)
m = meters (everywhere else)
s = seconds

[edit on 26-10-2005 by Protector]

Well, yes, I can tell you what it is.

Originally posted by siddharthsma
I was just playing around with E=mc^2, and rearranged it to get this

t = d/(2c^2)^1/2

t is time
d is distance
c is the speed of light

I got this formula but I have no idea what it is trying to say. Anyone have any ideas ?

First (and no offense) it says that you didn't understand what Einstein's equation is about (because time isn't in his equation.) You came up with a brand new equation.

What your equation is says that "if you go a certain distance at the speed of light, it will take you 't' amount of time."

This is a fairly standard algebra problem (usually presented as a word problem of the sort that drives me nuts ("You are going from Atown to Btown in a car that goes 35 miles per hour. How long does it take you to go 18 miles?")

Einstein's equation is about mass (the "amount of stuff") and what happens to it in the strange world as it moves faster and faster to approach the speed of light. It has nothing to do with distance or amount of time to get any place.

Here's a very helpful link that breaks it down pretty easy.

Browse around and find what you're looking for

www.pbs.org...

Time
Ever feel like time moves very quickly and sometimes very slowly? Like how the hours fly by when you're hanging out with a close friend, or how seconds drag on endlessly when you're stuck in traffic on a hot day? But you can't actually speed time up or slow it down—it always flows at the same rate, right?

Albert Einstein didn't think so. His idea was that, theoretically, the closer we come to traveling at the speed of light (186,000 miles per second), the more time would appear to slow down for us from the perspective of someone who, in relation to us, was not moving. He called the slowing of time due to motion time dilation.

Another link

Interesting stuff




[edit on 27/10/2005 by SportyMB]

Sorry I got the Equation slightly wrong.

But you can still make time the subject of the formula, it will just give you something slightly different.
I got this straight from a book, that explained how E = mc^2 is derived from the Shrinking factor. It clearly states that kinetic energy is involved. Therefore time can be made the subject because kinetic energy is = 1/2mv^2. and v = d/t .

therefore:
1/2mv^2 = mc^2

1/2m(d/t)^2 = mc^2

I need not go further, we all know how to make time the subject of the formula from here.

Please correct me if I am wrong

[edit on 27-10-2005 by siddharthsma]

Originally posted by siddharthsma

therefore:
1/2mv^2 = mc^2

1/2m(d/t)^2 = mc^2

No.

c is a constant (someone already posted what it is) and d and t are variables.

These are also two different forms of energy, Einstein's and kinetic.

Originally posted by siddharthsma
I got this straight from a book, that explained how E = mc^2 is derived from the Shrinking factor. It clearly states that kinetic energy is involved.

Site your sources if you can. Everyone who is interested enough to read this thread will be interested in your source.

I got the derivetion of E = mc^2 from a book called ' 5 equations that changed the world ' . One of the 5 equations that changed the world was E = mc^2.

Now a previous post by frosty pointed out c is a constant and d and t are variables ...

Notice that I have converted v into d/t , not c into d/t .

Or perhaps I did not understand what you said. Please explain it to me again if i am wrong.

[edit on 28-10-2005 by siddharthsma]

Originally posted by siddharthsma
I got the derivetion of E = mc^2 from a book called ' 5 equations that changed the world ' . One of the 5 equations that changed the world was E = mc^2.

What we're saying is that the book may not have explained it and its significance to you properly:
www.pbs.org...

The consequence is that you're using the wrong approach to break it down into other formulas. Here's a fairly standard (elementary) breakdown:
www.theory.caltech.edu...

Some history of the formula (Einstein actually didn't just invent it out of brute-force thinking. He had studied Newton and Pointcare (among others) who were working on the problem of mass/photons/light/electrons etc:
www.wbabin.net...

PBS' page is nice and unintimidating and does a good job of explaining:
www.pbs.org...

Now a previous post by frosty pointed out c is a constant and d and t are variables ...

Notice that I have converted v into d/t , not c into d/t .

Or perhaps I did not understand what you said. Please explain it to me again if i am wrong.

Here it is:
E (the amount of energy bound up in a particle or an object) can be measured by multiplying its mass by a fixed number (the speed of light, squared.)

I think I know what you mean, you mean to say:

Binding Energy = mass defect * (speed of light )^2

E = mc^2

I know that ! But it is possible to make time the subject of the formula, so I was thinking if maybe there was another way of looking at this formula !

Originally posted by siddharthsma
I think I know what you mean, you mean to say:

Binding Energy = mass defect * (speed of light )^2

E = mc^2

I know that ! But it is possible to make time the subject of the formula, so I was thinking if maybe there was another way of looking at this formula !

If you want to look at the formula from another way, do it the Newtonian way. Newton measured mass by using volume(I am very certain). See if you can achieve any similar results by using this method of substituting volume for mass. This is all I could come up with.

Now, what do you mean by 'making time the subject of the formula'? Are you trying to analyze Einstein's formula alone or compare it with the kinetic energy formula?

It is quite interesting, that when I made time the subject of the formula, I ended up at the well known equation :

t = d/v t - time d - distance v - velocity

I think that current day science has proven quite well that the speed of light isn't constant, there was even an article on ATSNN a while back that showed scientists had actualy stopped light for a certain amount of time.

And, Protector, to achieve traveling no distance, which would result in no time being passed, you would have to leave earth, sol and the galaxy, since all of them are constantly in motion.

Earth itself is going at over 20KM/s around the sun.

Now, what do you mean by 'making time the subject of the formula'? Are you trying to analyze Einstein's formula alone or compare it with the kinetic energy formula?

Ok now yo see what I mean is that when Einstein came up with E = mc^2, he first started by multiplying mass by the shrinking factor, to get the mass loss or defect :

M * 1/2v^2/c^2 = Mass defect = m

what he then noticed was that 1/2Mv^2 was the formula of Kinetic Energy, therefore he substituted 1/2Mv^2 for E .

E/c^2 = m = mass defect

therfore we rearrange it to : E = mc^2

now what I was saying about making time the subject:

because we now know that E is really equal to 1/2mv^2, then :

1/2Mv^2 = mc^2 now v = d/t so

1/2M(d/t)^2 = mc^2

Now I can't remember what I did, but I will find out and post the rest. But you see now how I have got time into the equation

Sorry I got the equation wrong again, it is

t = d/vc^2

Originally posted by siddharthsma
I think I know what you mean, you mean to say:

Binding Energy = mass defect * (speed of light )^2

E = mc^2
I know that ! But it is possible to make time the subject of the formula, so I was thinking if maybe there was another way of looking at this formula !

No. There's no time period in that equation. And it's not 'binding energy or 'mass deficit' ... sorry.

What Einstein is talking about is discrete "points" that don't have any relation to time OR distance. It is all time and no time simultaneously. He did discuss time in his Special Theory of Relativity, but the forumla there isn't E=mc^2

On THIS page is the forumla to use if you want to explore Einstein and equations involving time: www.glenbrook.k12.il.us...

Originally posted by thematrix
I think that current day science has proven quite well that the speed of light isn't constant, there was even an article on ATSNN a while back that showed scientists had actualy stopped light for a certain amount of time.

And, Protector, to achieve traveling no distance, which would result in no time being passed, you would have to leave earth, sol and the galaxy, since all of them are constantly in motion.

Earth itself is going at over 20KM/s around the sun.

When people refer to speed of light as a constant, they're referring to the speed of light in a vacuum, which is constant.

By the way, a course in Modern Physics would help everyone out, it seems. Or pick up Physics for Scientists and Engineers by Tipler...I believe that was the text I used when I took the course.

Originally posted by siddharthsma

Now, what do you mean by 'making time the subject of the formula'? Are you trying to analyze Einstein's formula alone or compare it with the kinetic energy formula?

Ok now yo see what I mean is that when Einstein came up with E = mc^2, he first started by multiplying mass by the shrinking factor, to get the mass loss or defect :

M * 1/2v^2/c^2 = Mass defect = m

what he then noticed was that 1/2Mv^2 was the formula of Kinetic Energy, therefore he substituted 1/2Mv^2 for E .

E/c^2 = m = mass defect

therfore we rearrange it to : E = mc^2

now what I was saying about making time the subject:

because we now know that E is really equal to 1/2mv^2, then :

1/2Mv^2 = mc^2 now v = d/t so

1/2M(d/t)^2 = mc^2

Now I can't remember what I did, but I will find out and post the rest. But you see now how I have got time into the equation

No, Einstein did not substitute 1/2mv^2 with E, that would make E=KE and E is not equal to 1/2mv^2 or KE. IF that were true Einstein's equation would not be in use as it would jsut be the samething as the kinetic energy equation.

Everything about c is constant and v is a variable. The time in c will not change in relation to distance, ever, unless you can prove that c is not a constant.

EDIT: Here is an example using both equations: we have a 16kg object thrown at 15m per second
Ke=1/2*16*15^2=1800
E=16(2.99x10^8)^2=143x10^8

Two different equations, two different answers.

[edit on 2-11-2005 by Frosty]