I'm an early raiser. About a month or so ago, I was up and on my deck at 4am with my coffee and iPod. I live in the foothills, pretty far from that pesky ambient city light and my view of the sky is great. It was a moonless night and I could make out the faint wisps of the Milky Way. I live on a canyon and have a very expansive space to see the eastern sky. Above and behind me are trees, but in front, over the canyon is nothing but sky. So I'm laying there on a chaise lounge, looking up when I became aware of something moving, straight up and coming from behind a tree to my rear, moving on a north east direction. It looked like a bright star and was no larger than a star. I thought 'airplane', but it was a constant light. Then I assumed it was a satellite. Then it stopped, dead in it's track. No slowing down, it just stopped moving and stayed in it's new position and appeared to be just another star in the sky. I've been thinking about it for a while now. I've seen satellites move before, they're usually quite a bit slower and when they approach their new position, they slow down even more. This object just zipped along at what must have been thousands of miles per hour considering it traversed relative distance from directly overhead to about 8 inches above the horizon in about a minute. Then just dead stopped. Any ideas as to what it was? Or how fast satellites travel?
The speed at which a satellite travels is dependent on its altitude. In general, the lower the altitude the faster the speed needed to maintain orbit. A satellite that would actually be visible to the naked eye would probably be in a relatively low orbit which means it would probably be traveling 15000ish miles per hour. That being said, the actual speed and altitude of an object in the night sky can be pretty hard to determine. It's the perfect situation for your eyes to play lots of tricks on you.
If you believe such a thing, the said "facts" are that it basically depends on the altitude of the orbit as said from the poster just above me. The farther away the orbiting object, the slower it moves. Just outside the atmosphere this is about 20,000 miles per hour. Objects in circular orbit always move at the same speed. Objects in elliptical orbit move faster when close and slower when far away. Here is a calculator for circluar orbit speed and period: http://liftoff.msfc.nasa.gov/academy/rocket_sci/orbmech/vel_calc.html
This was almost certainly a satellite. This is confirmed by the apparent speed, apparent magnitude, and direction of flight. Since it was directly overhead, it would have the fastest possible apparent motion from your location. The stopping appearance was, I suspect, an optical illusion caused by an unusual coincidence. I think the satellite rotated to a position where its reflective surfaces (such as solar panels) no longer aimed sunlight in your direction, causing the satellite to dim to a point where it was no longer visible. If this occurred just at the same moment when the satellite was in conjunction with a fixed star, it would appear that the satellite had become fixed (the non-moving object was the star, while the now-invisible satellite continued without being seen).
Satellite watcher here.. non-pro, but I get by! So far so good, sounds exactly like a satellite. They are only seen in the pre-dawn and dusk/early evening (for mid latitudes, anyway), they tend to be steady (although some may 'tumble' or catch the sun on solar panels etc). They move at a similar angular rate to a high flying aircraft (but see below), but usually with aircraft you can just detect the winking nav lights. This is a tricky question, but is your memory/observation 100% accurate on this point? Because Poor Debater is dead on with his guess, i reckon. Even if your eyes just flicked away or defocused for the briefest of nano-seconds, what he described can happen as the satellite suddenly hits earth's shadow (or angles the sunlight away from you by its orientation), and your brain just latches onto the nearest star and thinks it has stopped. Satellites can navigate a little by way of tiny thrusters, but come to a dead stop after moving quickly? Nah. Hmm. While I've seen them change direction *slightly*, I have never seen a 'relocation' as you just described. I'd like to see the footage of that one! Bear in mind that the rate at which they travel is almost entirely dependent on their altitude (faster lower, slower higher, stopped if high enough to be geo-stationary) and the direction of their orbit. So some go fast, some much slower..
Precisely why I posted the incident. A) it was about as bright as Venus in the morning sky...and about as large to the naked eye. B)It moved along at a rapid click, and then dead stopped. It didn't appear to be approaching some other bright star and 'meld' with it as suggested..there was no bright star in it's trajectory. This baby moved from 12 o'clock high to about 9:30 (the horizon being 9 o'clock) to the northeast Had I a ruler being held at arms length, I'd say it moved about 2 feet, in less than a minute. It kinda reminded me of one morning in the 60 somethings. I was driving up Dunes Ave in Vegas..top down. I caught sight of this light coming from over the Dunes Hotel. In a straight line, in my direction. It stopped as well and just stayed where it stopped. A few seconds later, another lighted starlike object appeared to depart the first one at a 90 degree angle....toward L.A. The first one just stayed where it stopped.
Got me. Can't think of any logical explanation. If it was that bright, one has to suggest either aircraft + landing lights, or ISS/Shuttle or something else quite large (eg spent rocket booster or large sat/solar panels). The speed is ok, but the stopping suddenly isn't. In the second example you gave I would point out that sometimes an aircraft with landing lights can look stationary for a few minutes if its trajectory is towards you, and then it can peel off at quite a rate. Plus, more than one aircraft can be taking a very similar path, if they are queued up for landing. Don't know that we can do much more, except to suggest you buy a good quality camcorder (with manual focus and exposure) and keep it hanging from your neck at all times..
I don't know if we are talking about the same thing, but for the past year or 2 I've noticed a very bright star in the sky that flashes blue, red, and white. I have Google sky on my phone, and when I point at the star the general area shows to be Monocerotis M50. It was 0538 when I saw it. Sirius is in that same area, so I think that's probably the most likely thing it could be, given the description of Sirius. Plus it kind of makes sense that any binary star system might flash the way this star seems to, depending on how hot the suns are, and the color it matches up w/on the visible spectrum. Add in the effect our atmosphere has on the light, and the fact its low on the horizon. This is totally a less than amateur attempt to explain that really bright star by the way, but prior to a year or two ago, I don't remember seeing such an eye catching star.
Certainly it was Sirius, the brightest fixed star in the sky. Sirius is blue-white, but oddly enough others have perceived it as red, too.
