Planes are similar, but tend to have flashing or colored lights and obviously aren't as far away.
I'm in a big city, but close to the ocean so I have a bit less light pollution. The city is also heavy military, so that could be part of the frequency.
Update: if you're near any of the spacex launches, you can watch the rocket too. I'm house sitting in Irvine, CA and saw the Monday launch go right near the house. Amazing to watch the plume from the rocket!
You should try to find one once, with the help of an app. It's not that difficult.
And of course, if it is 3am, and there is no sunlight at any altitude because the sun is on the other side of the world, no satellites are visible.
I could be wrong.
In general, you can see a satellite when it is overhead and illuminated by the sun. In the evening, it will appear in the west, moving towards the east ( almost all satellites go this way, not just ISS ). As it goes farther east, heading towards darkness, it will fade away. The ISS is bright enough to see a reddish tinge as it passes through sunset light.
Shooting stars go much faster than satellites.
2. The sky needs to be dark enough to see it (so twilight or night)
3. The satellite needs to be illuminated by the sun.
4. The satellite needs to reflect enough light that you can see it.
Basically this happens just before sunrise, and just after sunset. So the ground and sky are dark (allowing you to see through the atmosphere), and the satellite - being at high altitude - is still illuminated.
As they pass overhead, you can often see them suddenly vanish as they pass into the Earth's shadow.
The International Space Station is a good one to find, as it's quite bright (very large).
There are various websites and apps; some phone apps use the GPS and magnetometer to show you what direction and time to look, and a search tool to look for visible objects at your location. It used to be really good with the old Iridium satellites, which gave a bright flash due to their large flat antennas.
ISS is often visible in the middle of the day even in bright midday Southwest sun, if you know where & when to look.
I don’t know how you would know that. People are very bad at seeing distances at these scales.
If they were indeed satelites they could be starlink satelites. They are put into orbit as a bunch together and then they spread along their orbital path as they take up their position.
This article has a picture, maybe you can check if it is similar to what you have seen? https://earthsky.org/space/spacex-starlink-satellites-explai...
If you could recall more details then maybe we can figure out more exactly what this might have been. (Such as where you were, which direction you were looking at, when did this happen, how fast did they cross the sky and how far the dots were from each other. Were the line spread in the direction they were moving or sideways?)
I don’t remember the details anymore, but it was one of the coolest practical experiments we did.
I've seen plenty of satellites in the middle of the night, from very dark areas (wilderness). They look like stars, only they move more quickly. These observations go back a decade, at least.
I would guess, reflected moonlight (moon over the horizon) would be enough to light up the dot well enough to see unaided.
I can tell you that they look like stars - so much that I need a reference point, an actual star or planet, to verify they are moving and not a 'stationary' star (judging movement being otherwise very difficult at that distance). They move very steadily, horizon to horizon, or as far as I can track them. A wild guess, based on memory, is one might take 5 or 10 minutes to cross between my horizons (usually I'm not on a plain - trees, hills, mountains may elevate my 'horizons' and reduce the distance).
Natural celestial object? No way a star is moving that fast relative to other stars and Earth's horizons. Asteroid? That seems hard to believe, due to size and illumination. Comet? Are there lots of tiny ones? I never see tails. Maybe a meteorite entering the atmosphere that doesn't yet have a tail?
Other human-made objects? Airplanes would look bigger and have colored, blinking lights - I've seen plenty of airplanes at night. Maybe there are higher flying airplanes without the colored and blinking lights? Are they illuminated whitish, and so far away they'd look like stars?
I've seen them so many times, I'm confident that I could take anyone to a wilderness area on a clear night and find one within 15-20 minutes, probably less.
https://www.timeanddate.com/astronomy/different-types-twilig...
It's been awhile, but I'm pretty sure I've seen these much later than that. I'm talking about lying in a sleeping bag, looking up at the amazing starfields of pitch-black wilderness nights (tip: never use a tent except in extremis - look what you're missing!).
You probably just thought it was a star or a plane. They move but relatively slowly (even a fast LEO sat will cover the sky in about 5 minutes). They look just like a star apart from moving slowly. Depending on angles they can look pretty dim, especially the latest SpaceX sats. But the ISS is usually really bright because it's so huge and technically it's also a satellite.
You can tell them apart from a plane because they don't flash.
Edit: But yes there are several conditions that need to be met to see them like the other posters have mentioned. But every clear night near dusk or dawn you will see sats for sure. There are just so damn many in LEO now.
Yup 5-10 minutes is right. It depends on the orbit altitude and the height of the pass.
You can use sat tracker apps to identify which one you're seeing. I do this sometimes because I'm a ham radio operator and I track the one I want to use sometimes with a directional antenna.
> No way a star is moving that fast relative to other stars
No star moves relative to other stars when viewed from earth. They are all so far away they appear static. The starscape rotates as a whole (well it doesn't, the earth does, but to the observer it seems that way), but relative to each other they absolutely don't move.
If they do move, it is definitely a sign to stop drinking :) :)
> Asteroid? That seems hard to believe, due to size and illumination.
Also asteroids move way faster across the sky than a satellite. And they're rare except during that time of the year when they're really common.
> Comet? Are there lots of tiny ones? I never see tails.
Comets are incredibly rare in this galactic neighbourhood.
> and Earth's horizons. Asteroid? That seems hard to believe, due to size and illumination. Comet? Are there lots of tiny ones? I never see tails.
Higher orbits are visible for longer, due to the angles involved: because they're so high, such satellites can remain illuminated with the Sun further below the horizon. The Moon is the most extreme example: it's almost never in Earth's shadow.
And the distance - most asteroids pass by much further out than even the moon, so their motion would be hard to detect.
Very good point.
The flashing of satellites will generally be gentler than the short burst strobing of an aircraft.
