Weird Star?
August 15, 2008 8:01 PM   Subscribe

AstronomyFilter: What was that crazy thing I saw in the sky?

So I was camping with some friends in Wilderness State Park very near the Mackinaw Bridge in Michigan. On a very clear night we were all looking up at the stars watching for shooting stars and such. At one point my friend saw something moving incredibly, almost imperceptibly, slow. We followed it for quite some time and could easily tell it was moving based on a few reference stars that it was getting closer to or farther from. Eventually it seemed to stop moving and then slowly move in a different direction. It didn't move back the way it came from instead it sort of moved down with respect to the way we were looking, when before it was moving diagonally up and to the right. All this movement/stopping/movement again happened in the span of less than 10 minutes. What could it have been?
posted by bmalicoat to Science & Nature (19 answers total) 1 user marked this as a favorite
Elvis in a UFO. Bet your life on it.

Or, a satellite. Or some military test.
posted by Autarky at 8:19 PM on August 15, 2008

I know it's cliche, but it was probably a weather balloon.
posted by ten pounds of inedita at 8:19 PM on August 15, 2008

Airplane? They always seem to be moving slowly when viewed from the ground. It could have been moving in one direction and then veered off to its destination.

Or, UFO, which of course is the better option when you relate this story to your grandkids.
posted by amyms at 8:28 PM on August 15, 2008

Satellites should generally move in pretty straight lines or gentle curves. (Unless you were seeing something in, say, a Molniya orbit.)

My guess would be an airplane; airplanes moving almost directly towards or away from you appear to move oddly.
posted by hattifattener at 8:29 PM on August 15, 2008

maybe it was the ISS, and the change in direction an illusion caused by the station's orbital path moving towards the horizon?

maybe this page can help:

posted by spacefire at 8:36 PM on August 15, 2008

posted by spacefire at 8:36 PM on August 15, 2008

when before it was moving diagonally up and to the right.

An airplane approaching you at a constant altitude will appear to rise in the sky.

Eventually it seemed to stop moving

Descending almost directly towards you.

It didn't move back the way it came from instead it sort of moved down with respect to the way we were looking

The airplane turned to a vector less towards you, and continued to descend.

Your description is entirely consistent with observing an aircraft maneuvering to land at an airport, where the airport is (roughly) between you and the aircraft.
posted by pjern at 8:58 PM on August 15, 2008

Response by poster: We saw a few airplanes and what we thought were satellites that night. It didn't look like a plane because we saw no blinking lights and it was super small, about the size of the smallest star we could see and it never appeared to change size. Could this still be a plane?
posted by bmalicoat at 9:37 PM on August 15, 2008

Response by poster: I forgot to mention that this was always directly above us and never moved very far.
posted by bmalicoat at 9:39 PM on August 15, 2008

If it was always directly above you then where did it go? Or did you stop watching it?
posted by Citizen Premier at 10:18 PM on August 15, 2008

I saw something similar a few years back.

Thankfully, so did NASA.

No, we're not crazy, but at the end of my research they didn't know what it was, either.

(This video has been sped up, cropped, and taken out of perspective by NASA. It was filmed from the Space Shuttle itself, if my sources were correct. Feel free to do your own research, the video should have some identifying information in the titles.)
posted by Phyltre at 11:03 PM on August 15, 2008

Seems like somebody else saw this kind of thing too.
posted by nickyskye at 11:10 PM on August 15, 2008

The vectors of airliners traveling between Detroit and Seoul or Tokyo typically pass right over Northern Michigan.
posted by yclipse at 5:42 AM on August 16, 2008

I saw something like this too, years ago. It was like a tiny star, wandering back and forth.

I think what's happening is our eyes follow a satellite as it passes overhead, but as it moves we lose sight of it for a second or two. Our eyes then pick up the next moving thing we see, which happens to be another satellite moving in a different direction.

If this is the case, the perceived direction changes might happen more toward the horizon, where the thicker atmosphere makes it easier to lose sight of things.
posted by atchafalaya at 5:52 AM on August 16, 2008

There is an illusion that is easily reproduced with dim point sources and
darkened rooms with no surrounding stars. The dim point appears to
wander. It has to do with tracking problems the eye has when there
are no surrounding references. The motion is suggestible, also.

I've seen mylar balloons survive rather far from urban regions, and
if I saw one at night I wouldn't know what it was.

Was that a very clear night with or without a moon? What phase?
About what date? How much skyglow from your location?
posted by the Real Dan at 10:12 AM on August 16, 2008

Response by poster: We never stopped watching it, it was always directly above us and moved maybe 40-50 star lengths (I know that's pretty vague but I'm not sure how to quantify the amount of movement).

This was on Friday, August 8th, the sky was incredibly clear, no light pollution to speak of, I don't recall seeing the moon but it's possible it was too far above us the way we were laying and oriented to see without craning our necks.

It basically looked exactly like the video Phyltre posted but as he said, that has been sped up so it was quite a bit slower. Also the object in that video appears to retrace its old path, this one did not.

This was not near the horizon, it was almost directly 'up' from the ground. The reference stars we used were close enough that you could easily see the distance changing between them and the moving object.
posted by bmalicoat at 12:21 PM on August 16, 2008

I like hattifattener's idea of a satellite in something other than the usual low-earth orbit.

Satellites in LEO go through at 360° circle in 90 minutes. If you were watching them from the center of the earth they would cover half a degree — the apparent diameter of the moon — in seven or eight seconds. Watching from the surface, the apparent speed depends on how directly overhead the satellite passes: a satellite at an elevation of 45° is half again as far away as one directly overhead. So an satellite in LEO, no matter where you see it in the sky, should cross a lunar diameter in five or ten seconds. This is consistent with the ones I've seen.

hattifattener mentions the Molniya orbit, which keeps a satellite nearly directly overhead at high latitude for about eight hours. A satellite in such an orbit meant to dwell over central Siberia would spend every other orbit dwelling over Hudson Bay, within about 15° of the zenith to an observer in Michigan. It would be much further away than a LEO satellite, but you claim the seeing was excellent and the object was very dim.

You say the "turning" took about ten minutes. What time was this? How long did you observe the thing in total? Balloons and satellites in LEO can pick up sunlight for a while after things on the ground below them, but not all night. You say the turning took place over a few dozen star lengths; if your eye has a resolution of an arcminute, that would be one or two diameters of the moon?
posted by fantabulous timewaster at 1:35 PM on August 16, 2008

Response by poster: I'm guessing we started watching between 10:30 PM and 11:00 PM. I think it gets dark around 9 or shortly after during this time of the year. We watched that particular object over the course of 20-25 minutes or so. After it was 'at rest' for about 10 minutes (after the 10-15 minutes of movement) we stopped watching it. I would say a distance of two moon diameters is an accurate approximation of the distance it moved before changing direction.
posted by bmalicoat at 6:45 PM on August 16, 2008

Best answer: Wikipedia says that the only satellites in a Tundra orbit, another elliptical orbit, are the three used by Sirius Satellite Radio. If Google maps has placed your location correctly, and you believe the database in the next three links, those were highest overhead on August 8 at 06:50, 15:10, and 15:10 (even though the rise and set times are eight hours apart). SIRIUS-1 and SIRIUS-2 were both overhead at the time you were watching.

That guy has tools written for showing paths of satellites through the sky and over the ground, but they don't work for the sirius satellites — probably because they're overhead for 18 hours at a time, rather than fifteen minutes. He says he doesn't answer "what did I see" emails, but you might ask whether those satellites (or some others, he may know what's in his database) seem to trace loops in the sky.

Let me know if you figure this out. Retrograde motion is one of those things that confuses astronomy freshmen, and being able to point to something (even through a telescope) that seems to change direction over minutes instead of weeks would be a useful teaching tool.
posted by fantabulous timewaster at 10:37 PM on August 16, 2008

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