The light has been traveling for 55 million years. That has nothing to do with the launching of the satellite -- the light that the satellite is seeing is 55 million years old.

Right, the age of the satalite IS irrelevant, of course. But the fact that something 55 million light years away is detected and measure so acuratly by a telescope in such a short amount of time seems highly unlikly. I understand that this light has been present for so long and is still traveling, but I don't see how one could even see the black hole, which in fact was detected by X-ray light emitted by the collapse of gas molecules in the black hole itself( this things is 55 million light years away how can they even know that it is consuming gas?). The light is ancient, beyond ancient, yet it is still traveling. How can even the geometry, given the infinite number of angle posibilities for measurment, still seems to be missing a variable to determine it's true distence. You can't determine the distance the light has traveled without knowing the location of it's origin first. And you can't determine it's location without the distance the light has traveled. Given the two, you could triangulate the location of the black hole through the mentioned geometry, but with out the two, you have only the location of the light now.

The reason it found the black hole is because it was suspected of being there already (Most researchers agree that they exist at the center of virtually every galaxy), number one. Two, Like any terrestial telescope, viewing time is critical and dependent on many variables. On earth that includes weather, time of day, even the Aurora Borealis. Not so in earth orbit (well, not exactly true technically, but that is another subject), where the satellite is above the very atmosphere, clouds, weather, etc. So, most times, viewing time is almost 24 hours a day. This makes the wait time less for a particular group of astronomers looking for their special project, whatever that may be. Three, so how it found the object so 'fast' is answered in item one, and, that it is '55 million light years away' is determined AFTER the relative distance is calculated. And we use relative distance not as if it is inacurate or a 'guess', but that it is relative to the distances of other known objects. This is done by mathematics, especially geometry (there is trig and calculus used in other areas as well, but for now lets just keep it brief). This was discovered by the engineers of the Egyptians and Babylonians (they knew the 'Pythagorian Theorem' 1,000 years before the Greeks) some 4,000 - 5,000 years ago. It is as simple as saying that since we know the length of two sides of a triangle, we can figure the length of the other 'leg'. Modern survey crews use this every day. And fourth, light has been determined to travel at approximately 186,000 miles per SECOND (I won't get into how this is known, you will just have to trust me on this one, but it has been ascertained), generally. (Yes, I did qualify this because there are exceptions, but that is another whole area altogether.) So when someone says 55 million light years, they are referring to the distance light travels (again, at 186,000 miles/second) in 55 million years. Fifth, no one knew the light traveled that far, per se. That was not even determined until the calculations were in and triple checked. It represents a way of saying very large distances, and has been grabbed by the media in the last several decades. I hope you find this helpful.