548 00:46:58,400 --&amp;gt; 00:47:02,560 well, it's very exciting to actually be building a machine with this kind of 549 00:47:02,560 --&amp;gt; 00:47:06,560 precision to be able to do this, you know, we're measuring 550 00:47:06,560 --&amp;gt; 00:47:12,840 the arrival time of wave fronts of light to a very small fraction the size of an atomic nucleus.