Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Absolute Frame of Reference, Time

Name: Patrick
Status: student
Grade: 9-12
Location: PA
Country: USA
Date: April 4, 2011


Question:
Implications of Time Dilation I recently read about the Hafele-Keating experiment, with the atomic clocks placed on supersonic jets. If I understand it correctly, it proves that the faster an object move through space, the slower it experiences time. But our planet is already moving - the earth is speeding around the sun, the sun is turning around the edge of the galaxy, and the galaxy is still hurtling away from the center of the Big Bang. Does this mean that our planet, and everything in it, already exists inside a temporal distortion? That we are already "time-traveling?"



Replies:
Patrick,

According to relativity, time dilation depends on who is looking. The faster an object appears to move through space, the slower time appears to progress to who is watching it move. This applies to any observer that does not notice any major acceleration or strong gravity during the motion. When gravity and acceleration become important, it gets more complex. For a simpler situation, consider both of us moving toward each other. Your clock will look like it is moving slower, as I see it. My clock will look like it is moving slower, as you see it. The difficulty with such an experiment is that our clocks cannot be at the same place at the same time both before and after the experiment without accelerating at least one of them. Time is not absolute. Everything exists within time distortions, as seen by almost everything else. Time distortion is the common experience, not an unusual event. It does not matter in real-life for two reasons. First, we do not move anywhere near the speed of light and are nowhere near something with as much gravitational field as that of a collapsed star. Second, everything in our solar system moves almost together. If our solar system were inside a huge gravity field or should speed up by close to the speed of light, it would affect everything within the solar system in the same way. This makes relativity difficult to measure.

Dr. Ken Mellendorf Physics Instructor Illinois Central College


Yes, in relation to another frame of reference, say of Alpha Centuari. But almost all points on earth move at the same velocity, (same planet, same orbit, same solar system, same galaxy, etc.), it is not a problem. Even when places move at different velocities, say the poles and equator, the relative effect is minor.

R. W. "Bob" Avakian


Be VERY careful suspicious regarding assertions of "proof". Few, but possibility even only a very few, possible some or maybe even none, are actually "proved". "Proof" implies immutable truth under any and all conditions . You may encounter the term, but that does not imply an immutable "proof". Proof becomes an act of faith for a predictable set of assumptions. But that is an assertion about the "real" world. Keep your antennae tuned.

Vince Calder


Patrick -

The specific answer is "yes". But I tend not to call it "time-traveling", because the time distortion due to jet plane travel is pretty small compared to the normal passage of time in each clock.

I just consider most of the universe a little bit "warped", friendly but not quite perfectly "flat". Most of the universe experiences about a year for every year we experience, and if you need to know some other place's clock more accurately than that, then you are being picky and you need to do some relativity diagrams and math to get what you want. The people who set up and support our GPS satellite system have certainly had to do some of that, because they want their time to be exact to 1 part in 10^12 or some such. That is "picky with a purpose".

Jim Swenson


Time dilation, like velocity, is relative. An observer that is moving at a velocity different than ours (e.g. an observer not on Earth)could observe our time to be dilated. Since everyone and everything on Earth is essentially moving at the same speed, observers on Earth do not observe any significant dilation relative to each other. I would not consider this difference to be "time travel", though. That is simply the progression of time forward (albeit at different rates). There is no fixed "reference" time, so declaring a 'base' rate of time would be simply arbitrary.

Hope this helps, Burr Zimmerman


Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory