Special relativity: time dilation and length contraction

An easy way to understand why time dilation and length contraction occur at speeds near the speed of light.

Category:

Education

Tags:

• Special
• relativity
• time
• dilation
• length
• contraction
• moving
• clocks
• run
• slow

[williamtwu]

Thank you Dr. Wittmann. I didn't figure out in the class until your brilliant explanation. In the class, there are so much math, like Lorentz transformation. I learned the math but I didn't really get it. Dr. Wittmann, do you also have an as well brilliant explanation for the mass increase as object's speed approaches the speed of light?

[drdwittman]

@williamtwu Mass is just force divided by acceleration. Because of time dilation and length contraction, when an object is moving fast and you push on it with a given force, you don't measure much acceleration. So the mass appears to be larger.

[williamtwu]

@drdwittman Thanks! But do you have an explanation similar to Dr. Wittmann's? From Dr. Wittmann's video, the Lorentz transformation for time and space is clearly defined by gamma. But how about the mass? How do I see mass = inertial mass x gamma here?

[drdwittman]

@williamtwu That's all I have time for right now. The wikipedia page on this gives a reasonably clear explanation.  Be aware that accelerations along the direction of motion are subject to different gamma factors than accelerations transverse to the direction of motion (longitudinal vs transverse mass).

[smcam3]

Superman (at light speed) should also hit point B in exactly one year from my viewpoint. Special relativity states that light travels at a constant C to all observers, so Supermans laser should also hit point B in exactly one year from my viewpoint. How does this leave any room for Superman to observe his laser traveling at the speed of light? Even if he flew at 99.99999% speed of light, wouldn't he just watch the laser right in front of him, i.e. at a very slow speed relative to him?

[drdwittman]

@smcam3 You have just proven that Superman can't fly at exactly the speed of light. At 0.9999999c, his measures of time and distance are so dilated and contracted that he also measures light traveling at a velocity (distance/time) of c.

[sniped101]

@meucunt1 wait a second.. if i did that right, you would be having a 204 second diliation going the speed of light?

[sniped101]

@alcolyte76 matter can travel faster than the speed of light?

prove it?

[freethinker3733]

This is so good and simple an explanation....first time i saw this simple explanation...great!!! thanx dr wittman

[ChezJazza]

Thanks heaps <3

[420dankykush]

@meucunt1 well said

[meucunt1]

@420dankykush Actually I checked his channel page last night, saw his comment battle with you and others. The comment that sticks in my mind is the one where he uses the phrase "evilution". It is clear to me now that this discussion is pointless, if a man does not value logic or empirical evidence what logic or empirical evidence can you present to change his mind. I'm done here, whatever unfounded fallacy he spews as a reply will be the last word.

[420dankykush]

@meucunt1 i know right man hes stupid i smoke a fair share of ganj and even i understand any and all matter's mass contracts and densifies relative to its velocity

[meucunt1]

@alcolyte76 (1) Again you dodge the question and just regurgitate crap about your education and neutrinos moving faster than light. The former I have no interest in, still. The latter, as stated in earlier replies to you is far from verified and very unlikely to be true.

It boils down to this, YOU disagree with the accepted scientific consensus at this moment in time. You say that the tests are fallacious due to the effects of speed on atomic clocks. Cont....