background: I am retired physician living in western Boston suburb. It is under the north landing flight path to Logan, 5 mi east of Hanscomb AFB, and I have experience in knowing civ and military aircraft.On Friday, 9/11/15,my 42 y/o son yells into front door from open front porch "you have to see this, a UFO." As a huge skeptic, from our west-facing front porch we both observe: 1) a bright orange light hovering well-above treetop level at 240 degrees WSW to our position (my son said he had seen it move slightly up, then right, then left in the prior 2 minutes); 2) it appeared to be over 5 miles away, directly in the direction I had seen jets come from NYC headed to Europe over a thousand times; 3) this light was hovering, steady and less than 1/10 the altitude of a jet: 4) while the jet had white, red and green lights strobing, this object was steady, no red, no green, no white.; 5) the jet appeared to be 50% larger in size than the bright orange light, only vaguely outlined (but no contrail). I immediately announced that I recognized it as a helicopter on a course from CT or western MA to Boston and that "the light was orange due to distortion." At 8:46 I heard a jet pass directly over the house from NE to SW, it appeared to be a typical Europe inbound to NYC at 40,000 feet, with contrail visible in moonlight, and flashing lights. When 3-5 miles southwest of us, with diminishing jet noise, with the wings of the jet visable in the moonlight, the hovering orange craft shot upwards in elevation and a direction NE directly at the jet, at a speed that was 3-4 times that of the jet. I thought they would collide, and had I not seen it previously hovering, I would have thought it to be a missile.With the orange light craft superimposed on the jet,the orange craft was about 1/2 the size of the jet passing over Lexington at 8:46 pm. Immediately after,I saw the jet continue in a path toward NYC, but the orange light hovered at an altitude matching the jet at least 1/2 the way from my position from when initially seen, directly west of my position. After 15 seconds, the orange craft accelerated to 3-4x jet speed in a new due East direction at altitude of approx. 40K feet and disappeared to the East over the Atlantic Ocean. There never was any sound of a jet, plane or helicopter. There was no training with jet fighters at Hanscomb AFB that night.An additional issue, from when the orange craft was first sighted, there was a blue light that was 10 times smaller or less bright that was moving from South to North and North to South in the immediate area of the horizon where the orange craft was seen. This encompassed less than 5 degrees of moving from about a bearing of 235 to 245 degrees. I did not even look for the blue light for the next 10 minutes, watching only the orange light. When the orange craft disappeared over trees to the East, the blue light was still present, appeared to move a few degrees North, then South, then disappeared over the western horizon. The orange craft made no noise, no contrail, emitted steady light, had no appearance or lighting of a jet, it accelerated from a hover to speed of at least 2K MPH instantly, and I was overcome with fear it would collide with the westbound jet. That jet and radar images will have to show something.