how to distinguish satellites from ufos

Hello there,

sorry this might be an easy to answear question but since we hat a wonderfull bright night this eve, and we saw like 5 sats / ufos in about 20 mins, i wanted to ask how to seperate a sat and an ufo clearly!

the lights me and my girlfriend saw where passing the nightsky very fast, in different directions and with high speed at, what i can tell, a high altitute (compared to airplanes)

how come does a satellite (if they really were) is shining as bright as a star? is it sun reflection, spotlights (?!) or reflecting solar panels? the ones we have seen passed the night sky in about 20-30 seconds, there were no flashing lights and they moved in different directions at different speeds (maybe different altitudes aswell?)

another question that raised in my head is how do the satellite operation companys manage not to crash their satellites with others? afaik there is no controlling device on the sats - and if we saw 5 in 20 minutes, beeing in a very bright location - where u can hardly see a bright night sky, how much more would be visible in a low populated, dark area?

thanks in advance

[edit on 7-8-2009 by s.one.z]

The satellites I've seen were pretty dim. Around 5th or 6th magnitude.
They're lit by sunlight up in the atmosphere. A satellite flare is when a highly reflective panel catches the sunlight and shines it directly onto the ground. Never seen that happen, but it can be brighter than Venus. Some can even be seen during the day.

I think there is a controlling agency to keep track of commerical satellites.
It's planned out before a new one is put into orbit. Collisions have happened, but space is huge, so it's rare.

[edit on 7-8-2009 by Schaden]

For one, satellites travel in a straight line and at a constant speed. They do not change direction or speed to a degree that would be visible to the naked eye. If you see this happen then you are not looking at a satellite.

Originally posted by s.one.z
the lights me and my girlfriend saw where passing the nightsky very fast, in different directions and with high speed at, what i can tell, a high altitute (compared to airplanes)

Satellites orbit the Earth at various heights, the 'lowest' being two to five hundred miles up. The ISS for example is about 220miles high on average (it varies a little). The Hubble Space Telescope is about 350 miles up. These are classed as low orbits. There are around 8,000 satellites out there at this height and maybe 100,000 bits of debris. All travelling around 17-20 thousand MPH. There are another cloud orbitting at about 20,000 miles out. These are geostationary and have the same angular velocity as the Earth, so they appear to remain stationary in space.

how come does a satellite (if they really were) is shining as bright as a star? is it sun reflection, spotlights (?!) or reflecting solar panels?

It's all due to reflected sunlight. At these heights, the sun is still shining when on Earth it's dark. Of course there are times of night when you can't see any satellites because the sky is in total Earth shadow. A few hours around local midnight when it is impossible to see satellites. Any bright light moving across the sky at midnight can't be a satellite.

the ones we have seen passed the night sky in about 20-30 seconds

Satellites can't cross the entire sky (from horizon to horizon) in much less than 6 minutes. It's simple orbital mechanics. The ISS takes 6 minutes when it crosses in a high pass (the visual elevation varies every pass due to the Earth and the satellite both turning). Very high satellites (500 miles or so) take much longer, even though their speed is higher than the lower orbits.

they moved in different directions at different speeds (maybe different altitudes aswell?

They move in almost every direction.

how do the satellite operation companys manage not to crash their satellites with others?

Space. It's a big place. Crashes are very rare, but do happen. There was one a few months ago. It created another cloud of debris, maybe 10-20,000 pieces. All the stuff larger than a baseball is tracked by NORAD so they know where everything is at any time.

WG3