jahman, your new animated avatar with the wiggling dotted line -- what does it represent??:(

Intrigues me too.Looks like a cross hair following a flight-plan across the antarctic...Nice though.

Nice of you to ask!This funky avatar is "relatively special", as in Special Relativity.The diagram depicts the World Line (trajectory) of an observer: The bottom quadrant (light-cone) is the visible past, the top quadrant the available future. The vertical axis is time, while the horizontal axis is distance.The diagram thus depicts space vs. time, i.e. "space-time" and shows how space-time is distorted due to acceleration of the observer. The dots are just random events in space-time that are there to make the distortion of 4D space-time visible in this 2D diagram.The link between special relativity and aviation is GPS: GPS satellites move fast enough WRT us on the ground that their orbital centripetal acceleration distorts time as per this diagram, thus the GPS system needs to adjust the onboard atomic clocks for time dilation so they can remain in synch (within 14 nanoseconds) with International Atomic Time).For a (non-mathematical) understanding of Special Relativity, see:1. The Paradox of Special Relativity2. Centre of the Lightcone3. Time DilationCheers,- jahman.

Ah, thanks for the explanation (I think..)

About 1 second in 72 years by Neil Ashby's reckoning, cited in Wikipedia. That's quite a lot and enough to introduce big inaccuracies (1 ns will give a 1 metre error suggesting 1 us might give 1 km error). it didn't occur to me they were moving so fast.http://www.ipgp.fr/~tarantola/Files/Professional/GPS/Neil_Ashby_Relativity_GPS.pdf, most of which I actually understood (surprised my mentally atrophied self). At least while I was reading. Inrteresting to see that his research led to allegations of industrial espionage.On the other hand, my watch gains about 72 seconds each year...

About 1 second in 72 years by Neil Ashby's reckoning, cited in Wikipedia. That's quite a lot and enough to introduce big inaccuracies (1 ns will give a 1 metre error suggesting 1 us might give 1 km error). it didn't occur to me they were moving so fast.http://www.ipgp.fr/~tarantola/Files/Professional/GPS/Neil_Ashby_Relativity_GPS.pdf, most of which I actually understood (surprised my mentally atrophied self). At least while I was reading. Inrteresting to see that his research led to allegations of industrial espionage.On the other hand, my watch gains about 72 seconds each year...

An interesting article! (at least the half I understood...) Now I realize there is also gravitational time distortion (General Relativity) as well as time synchronization difficulties (Sagnac Effect, of ring laser gyro fame) due to the angular speed of the satellites.Your watch's accuracy is terrible (but way better than mine!), at least as compared to NIST's quantum clock that measures time to an accuracy of 4 seconds since time began 13.8 billion years ago, and does so by relying on a single aluminum atom, meaning the FMC could tell you how to steer your aircraft on the ramp and stop exactly at the gate (GPS would have 10 cm accuracy).Project GREAT: A time-nut (clock hobbyist) took his three caesium atomic clocks for a weekend up to a lodge at the base of Mt. Rainier at 5,400 ft MSL to measure time dilation. When they got back home (1,000 ft MSL) they had gained 23 nanoseconds on the rest of us.Cheers,- jahman.

Why does he get an animated avatar: while mine had its animation frozen? Cheers, - jahman.

And HoratioWonderSocks also has this cool animated avatar, while mine remains frozen.Have emailed tech support several times to no avail (or even a response...)Cheers,- jahman.

Perhaps yours is too big? When it appears in your post it is a lot larger than it appears as your avatar. Maybe it was automatically resized when you attached it and it lost it's animation (ie when it was automatically resized on the first frame was kept).

Perhaps yours is too big? When it appears in your post it is a lot larger than it appears as your avatar. Maybe it was automatically resized when you attached it and it lost it's animation (ie when it was automatically resized on the first frame was kept).

That is very correct.

Perhaps yours is too big? When it appears in your post it is a lot larger than it appears as your avatar. Maybe it was automatically resized when you attached it and it lost it's animation (ie when it was automatically resized on the first frame was kept).

That is very correct.

Thanks, guys, that's what I thought, so after the BBoard upgrade I re-submitted my avatar, to no avail. I wouldn't really insist and just pick a new avatar, except that it did animate before the BBoard upgrade. Odd! Cheers, - jahman.

It'll work if you resize it to 100 by 100 pixels.

Thanks! Alas I have no idea how to resize an animated GIF... Cheers, - jahman.

Here you go: http://dl.dropbox.com/u/18934189/Lorentz_transform_of_world_line.gif

Cool! My avatar's alive again! Many thanks! :biggrin:How did you do it? Cheers, - jahman.