1 00:00:00,000 --> 00:00:02,000 Now, maybe you don't believe me, maybe you don't believe that 2 00:00:02,000 --> 00:00:05,000 special relativity could possibly be for real. 3 00:00:05,000 --> 00:00:09,000 Clock's disagreeing with each other--what's going on, how do we test it. 4 00:00:09,000 --> 00:00:13,000 Well, as a matter of fact, we're actually testing special relativity right now, 5 00:00:13,000 --> 00:00:18,000 and we're doing that with a series of GPS satellites which are constantly in orbit over earth. 6 00:00:18,000 --> 00:00:24,000 The way these satellites can localized someone's position on earth so precisely involves 7 00:00:24,000 --> 00:00:30,000 precised measurements of distance between each satellite and the observers' GPS device. 8 00:00:30,000 --> 00:00:34,000 This precised distance measurements actually require a precised time measurements, 9 00:00:34,000 --> 00:00:38,000 but these satellites are moving relative to the earth, relative to the observer. 10 00:00:38,000 --> 00:00:42,000 In fact, they're traveling at about 14,000 km/h. 11 00:00:42,000 --> 00:00:46,000 Can you tell me what β is associated with 14,000 km/h-- 12 00:00:46,000 --> 00:00:50,000 a.k.a. what fraction of the speed of light is this. 13 00:00:50,000 --> 00:00:52,000 Enter your answer in scientific notation. 14 00:00:52,000 --> 99:59:59,999 I've put the 10 in here for you and you can put the exponent in here and the rest can go right here.