No but I lived there for three years, 6-8 grade, Augsburg und Bamberg.. Im Augsburg Zweiunfunfzieg Uhland Stasse, vertilich. Hmmm, maybe so. We'll see. But by then I should have you cured of any relativity theory addictions, which would force your astroids video to something more real, and I add, more useful. Do you know NASA has an anti-astroid-collision program going? Get on as a student/intern . . . [there is no trying to get on as an intern, with pay, there is only GETTING ON].. . .. Promise your mom you'll be a good boy and will drink at least a quart of milk a day, get the internship and dad will buy you something more than appropriate for your educational advancement. Video games and physics, all decisions removed, but you have to maintain a continuosly patient persona with those arrogant NASA scientists when asking the frequent question, "will you please prove it to me?" quote geistkiesel- " Someone earlier called me arrogant for daring to do what I do here. So, now "arrogant" is a bad thing is it? " and someone reminded me of this statement. But thinking you can outsmart a century of dead guys is the easy part, they can't argue with you. Arrogant Message received and understood. As a self-claimed self-starter I can assure you that "we" need external stoppers from time to time. Even though I am a admirer of the country's greatest actor of all time, John "Duke" Wayne, who said, "never apologize, its a sign of weakness.", there are always 'adjustments' that can be made. You might be surprised at the transformation seen in this threader's consideration of possible reference frame modifications of his modus operandi. After all, my favorite baseball player of all time, the maestro pitcher, Leroy "Satchel" Paige with infinite wisdom stated: "When facing an enemy stronger than you, walk him." You can also review your acceleration history were you thoughtful enough to maintain such. But this would be more fun. Here is what I would do next. Code: M| |<-----------|o |--------------->|o |_______L______| I would have a device that emits a photon at o in the direction opposite to the velocity of my train to a reflecting mirror at M. M and the photon therefore are on a collision course. Knowing L I can determine the distance equation for the round trip of the photon, or L - vt + L = tc and from this solving for v, and measuring t, I get the velocity of my train, v = (2L - ct)/t. Let's say I calculate 4.6meteres/second. Next I take a ten meter stick and apply some superglue to each end. I hold the stick parallel to the other train's direction of motion and flip the stick across the gap. My trusted and very able assistant down stream from my position measures the time it takes the stick to pass her eye position, say 1 second. So our relative velocity is 10meters/second. Adding the two velocities, or subtracting if the additon comes out contradictory measurements, you determine the complete motion profile of your train system:10 - 4.6 = 5.4meters/second.QED. How would you do it? I can give one answer right now regarding approaching astroids: Duck!.