Don't Make Me Turn This Meteor Around!
September 27, 2010 7:13 PM
So, what object did I fail to identify?
So it's dawn during a trip to visit relatives circa 2005. The sky is absolutely beautiful, and I'm not driving, so I'm watching the stars fade. At the point where the sky becomes completely blue, and is almost at full brightness, I notice an extremely remote point of brightness that looks like a small star. And it's moving at a fair speed, considering that it looks like it's well up in the atmosphere. . Its trajectory and size lead me to believe it was possibly the ISS--I'd heard that it could be visible at dawn in some instances.
Except, the star-like dot reverses course and goes back the way it came, eventually being obscured by some clouds over on the left side of the sky, spending a few minutes, less than 5, in full view while progressing across perhaps a third of the morning sky. Which seemed like a rather strange trajectory to me, but nothing terribly remarkable, so I wrote down my account on a general discussions forum and forgot about it.
Until! I'm watching video from NASA STS-114 on the History Channel (totally by coincidence) quite a bit later and I see this bit of video. This video is sped up, apparently, but it's exactly like what I saw. The object comes into view at speed, slows, stops, and accelerates out of frame. (The lights in the background of the video, apparently, are Earth cities. I've heard it thrown around that the space shuttle was orbiting at some crazy speed at the time.)
So, what did I see? Obviously I can't say absolutely that what is seen in the video and what I saw are the same phenomenon, but subjectively they looked exactly the same, just in real-time for me. I saw the object in November 2005, the space shuttle video was recorded in August 2005, but I didn't see the video until a year or so later. I keep forgetting about this for longer and longer periods, so I'm curious if anyone has any insights.
So it's dawn during a trip to visit relatives circa 2005. The sky is absolutely beautiful, and I'm not driving, so I'm watching the stars fade. At the point where the sky becomes completely blue, and is almost at full brightness, I notice an extremely remote point of brightness that looks like a small star. And it's moving at a fair speed, considering that it looks like it's well up in the atmosphere. . Its trajectory and size lead me to believe it was possibly the ISS--I'd heard that it could be visible at dawn in some instances.
Except, the star-like dot reverses course and goes back the way it came, eventually being obscured by some clouds over on the left side of the sky, spending a few minutes, less than 5, in full view while progressing across perhaps a third of the morning sky. Which seemed like a rather strange trajectory to me, but nothing terribly remarkable, so I wrote down my account on a general discussions forum and forgot about it.
Until! I'm watching video from NASA STS-114 on the History Channel (totally by coincidence) quite a bit later and I see this bit of video. This video is sped up, apparently, but it's exactly like what I saw. The object comes into view at speed, slows, stops, and accelerates out of frame. (The lights in the background of the video, apparently, are Earth cities. I've heard it thrown around that the space shuttle was orbiting at some crazy speed at the time.)
So, what did I see? Obviously I can't say absolutely that what is seen in the video and what I saw are the same phenomenon, but subjectively they looked exactly the same, just in real-time for me. I saw the object in November 2005, the space shuttle video was recorded in August 2005, but I didn't see the video until a year or so later. I keep forgetting about this for longer and longer periods, so I'm curious if anyone has any insights.
If it's dawn, then you're at the leading face of the earth travelling around the sun. It could have been a meteor.
As for the trajectory, think about a football being thrown toward you. It "rises" in the sky, then the atmosphere and gravity tug it down and it falls well before it gets to you. Instead of at the same level, imagine the thrower being really high, and the scale of 80 miles or so. With a sky with no immediate frame of reference nearby, it can look very strange indeed.
posted by cmiller at 7:34 PM on September 27, 2010
As for the trajectory, think about a football being thrown toward you. It "rises" in the sky, then the atmosphere and gravity tug it down and it falls well before it gets to you. Instead of at the same level, imagine the thrower being really high, and the scale of 80 miles or so. With a sky with no immediate frame of reference nearby, it can look very strange indeed.
posted by cmiller at 7:34 PM on September 27, 2010
Possibly some instance/iteration of retrograde motion.
posted by Emperor SnooKloze at 7:35 PM on September 27, 2010
posted by Emperor SnooKloze at 7:35 PM on September 27, 2010
If I witnessed this, based on everything you said, I would assume it was a medium to large military or civilian experimental plane of some sort at high altitude and high speed, initially moving away from tor toward you, maybe 20-30 miles away, then banking quickly and moving perpendicular to you. So you perceive it as moving slow, stopping, then moving quickly. A lot of planes with silver or white undercoats are pretty damn reflective, especially at low sun elevations, so I'm sure it would have looked like a star of some kind. Where I live I see a lot of FedEx planes (white paint) at anywhere from 10,000 to 30,000 ft, only 5 to 10 miles away, and they've VERY noticeable even with no contrail. It would help if we knew where you saw this, since this might pin down what kind of airspace or flight testing activity might be happening where you saw it. If the motion was unusually fast you might have been looking at a drone of some kind at close range.
I worked in the Air Force in atmospheric sciences, so that's my educated take on it. There's often weird stuff up in the sky, and it's great you notice those things, but it's almost always easily explained. If that doesn't sound like a good explanation then we can go for the swamp gas angle I suppose.
posted by crapmatic at 8:01 PM on September 27, 2010
I worked in the Air Force in atmospheric sciences, so that's my educated take on it. There's often weird stuff up in the sky, and it's great you notice those things, but it's almost always easily explained. If that doesn't sound like a good explanation then we can go for the swamp gas angle I suppose.
posted by crapmatic at 8:01 PM on September 27, 2010
Hey, what's the orientation of this object relative to the Earth in this video that you linked to? I'm inclined to agree with Emperor SnooKloze's assessment; which is, I reckon, just about equivalent to cmiller's scenario. The video you linked to looks, to me, like something orbiting the Earth at a lower (smaller radius!) orbit than the camera. If the Earth is to the right of the frame here, then the object in the video is coming around the Earth, reaches the maximal elongation of its orbit (relative to the viewer) and then continues along its orbit, appearing to the viewer to change directions. (I sort of think that one is a bit of space debris orbiting the Earth, but the motion of that object relative to the Earth would tell us more about what kind of object it could be.)
It's all about the apparent motion (for the viewer) which is a combination of the object's motion relative to the viewer's motion. This stumped natural philosophers for centuries! Most of us don't have an intuitive sense about relative motion -- think about how weird it feels when you're sitting in a parked car, and a car next to you starts moving. You feel, for a second, like your car is suddenly rolling.
For funsies, I'm going to link to my favorite of all Middle Ages philosopher, Nicole Oresme, and his proof that we can't tell based on sense information that the Earth is stationary and the Heavens move about it. Down the page, at section 1b: "I make the supposition that local motion can be sensibly perceived only in so far as one may perceive one body to be differently disposed with respect to another."
posted by Made of Star Stuff at 8:29 PM on September 27, 2010
It's all about the apparent motion (for the viewer) which is a combination of the object's motion relative to the viewer's motion. This stumped natural philosophers for centuries! Most of us don't have an intuitive sense about relative motion -- think about how weird it feels when you're sitting in a parked car, and a car next to you starts moving. You feel, for a second, like your car is suddenly rolling.
For funsies, I'm going to link to my favorite of all Middle Ages philosopher, Nicole Oresme, and his proof that we can't tell based on sense information that the Earth is stationary and the Heavens move about it. Down the page, at section 1b: "I make the supposition that local motion can be sensibly perceived only in so far as one may perceive one body to be differently disposed with respect to another."
posted by Made of Star Stuff at 8:29 PM on September 27, 2010
That video clip doesn't look like a rapid change in direction to me. It looks like a rapidly moving object banking to the right, sort of going around an imaginary corner.
posted by emelenjr at 7:11 AM on September 28, 2010
posted by emelenjr at 7:11 AM on September 28, 2010
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posted by MikeWarot at 7:32 PM on September 27, 2010