I was just in the yard (right on a lake 10 miles west of Phillips WI)enjoying a nice fire. Clear skies, no moon, dead quiet, and then three bright orange lights travelling in a line from south to north. First thought was military aircraft. Then, as each passed overhead, their lights would slowly dim and then disappear. Two minutes later, a fourth light followed, easily twice as bright as the others. Based on their speed, I would guess they were travelling at 20,000' or so. What troubles me is this. There was no noise, and there were no strobes, beacons or navigation lights. Not normal, by any standards. I should have heard something.