[Physics] Is it possible to see satellites with the naked eye

astronomyplanetsstars

Every now and then I notice some very bright "stars" in the sky. They tend to be very few (one or two, usually), and are quite much brighter than any other star out there. Often they're perfectly visible and bright even in dusk, when no other star is visible yet or will be for some time to come.

Now, I'm writing the word "star" in quotes because I really don't think that they're stars. But what are they? Planets? Satellites? Latest Chuck Norris encounters leaving the atmosphere?

My best guess would be that they are satellites, because planets should be about the same brightness as stars, but that sounds pretty implausible as well… And yes, I'm very certain that they are NOT airplanes.

Best Answer

If they're sitting still, and are very bright, they are planets.

Install Stellarium on a computer or a smartphone. First time you run it on a computer, enter your location in the settings (no need to do that again after the first time); on the smartphone, it deduces the location automatically each time. The program will show you what planets are visible at that time in your place. Drag the map around, zoom in and out, turn on/off labels and stuff - there's a lot to see in that program.

Right now, Venus and Jupiter are visible everywhere, trailing the sunset in the western sky. Mars is a bright dot rising in the East. That's what you're probably seeing.

Satellites are also visible, but they move, most of them pretty rapidly. There are websites and smartphone apps that can let you predict when the ISS (International Space Station) passes above your place. You could go outside and watch it - it's a bright dot moving quickly on the sky.

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