Recent content by lowemack

If speed is simply distance traveled divided by time taken then, if I go to Proxima Centura in my space ship, I know it is 4.2 LY away, I could go fast enough that only 2.1 years pass on my clock on my space ship. Why could i not say I traveled at twice the speed of light?

I understand that C is constant, and using the Lorentz formulas you can work it out. What I have trouble grasping, and a few others on here also, is that when we travel towards a light source at 0.25C, we would expect to measure the light at 1.25C. When we ask why not we get told, "ah, it's...

I have the same trouble with this. If I am traveling at 0.5C towards the sun and measure the speed of light from it, we get told that it still measures C because of our time dilation and length contraction. But the same reasons can't explain why the speed of light from the Earth, which I am...

If both sensor cables were the same length, and the start and stop signals took 1 second each to reach the clock and the time taken for light to travel the distance between the sensor was 0.2 sec, then at T=0 start sensor activated, T=0.2, stop sensor activated, T=1, clock started, T=1.2 clock...

I know there is a problem with measuring the one way speed of light, but why can we not use just one clock. If somebody could explain the problems with this method, then it might help me to understand. Can we measure the one way speed of light the following way:- Have a long sealed tube with a...

Thanks ghwellsjr. Great explanations that help a lot. Would the spaceman still get the same distance (2.1LY) if he tried to measure the distance he traveled away from Earth by using this method of radar/laser echo?

How would the spaceman be able to tell that the distance he traveled was less than 4.2LY. If he had a tape measure on the spaceship, and he fastened the end to earth, would it not measure 4.2LY when he got to proxima centura? If it measures less because the distance traveled is shorter...

How does a spaceship log fewer miles, how can you tell it is the distance that got shorter and not you arriving quicker than faster than light travel would allow. How would you be able to tell when you arrive at Alpha Centura in 2.1 years that the distance you traveled was less and you didn't...

Apologies, I did mean 2.1 years, not light years, and I am pretty sure that from the spaceships clock the journey could be done in 2.1 years, relativity does allow this.

How do you measure a distance in a reference frame that is moving close to C?

How would you know that it is the distance that is shorter and not the speed faster?

Please help me to understand. In theory with a powerfull enough ship a space man can travel to a distant star, say Proxima Centura (4.2LY away) in 2.1LY by his own clock, yet on Earth and Proxima Centura more than 4.2 years will have passed. My question is why will he not measure Proxima...

If mass really increases with speed then if 2 rockets leave earth, traveling parallel and close together, at close to the speed of light, then from an Earth point of view, as their mass increases, so should their gravity and they should be drawn together. But from the spaceship point of view...