Distance travelled by light

hubble_bubble · Aug 18, 2012

Is it true that the distance traveled by light during a particular time period is expressed by d=tc^2 where d is the distance travelled in metres and t is the elapsed time in seconds?

Muphrid · Aug 18, 2012

Distance = time x speed

What you wrote is the equivalent of distance = time x speed^2. That doesn't make sense.

hubble_bubble · Aug 18, 2012

Sorry the time is in Planck time not seconds. My mistake.

Muphrid · Aug 18, 2012

The Planck time is still a time. The equation makes no sense just on dimensional grounds. A time multiplied by a speed squared doesn't give a distance, regardless of units.

hubble_bubble · Aug 18, 2012

Muphrid said: ↑

The Planck time is still a time. The equation makes no sense just on dimensional grounds. A time multiplied by a speed squared doesn't give a distance, regardless of units.

Well it does work. The units all balance.

Muphrid · Aug 18, 2012

By all means, if the units do balance, then I am here to learn. Show me.

hubble_bubble · Aug 18, 2012

Sorry I messed up.

It should be dc^3 = tc^2.

That's where I needed the cubed value.

Muphrid · Aug 18, 2012

speed = distance / time

Distance x (distance^3)/(time^3) is not equal to (time)x(distance^2)/(time^2), right?

hubble_bubble · Aug 18, 2012

Sorry scrub that I have mixed up two sets of equations. It is 12.53 AM here.