11
$\begingroup$

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.

Improve this question
$\endgroup$
4
  • $\begingroup$ At what time of year and in what hemisphere are you viewing these bright "stars"? $\endgroup$
    – honeste_vivere
    Commented Feb 18, 2016 at 1:05
  • 1
    $\begingroup$ @honeste_vivere - Northern hemisphere, at spring 4 years ago, as you can see in the question. :D Also, I'm not much of a stargazer, this was just a one-off curiosity question. :) $\endgroup$
    – Vilx-
    Commented Feb 18, 2016 at 9:03
  • $\begingroup$ I am guessing Venus was up in the morning then. In the evening, I do not recall which stars are bright in the spring. I just recall that Venus is the morning star in the spring and the evening star in the fall. It can be very bright at times... $\endgroup$
    – honeste_vivere
    Commented Feb 18, 2016 at 14:18
  • $\begingroup$ @honeste_vivere - It was pretty certainly the evening when I noticed them (also hinted at by the word "dusk" in the post). I don't get up early enough to see the sunrise at that time of the year. :) $\endgroup$
    – Vilx-
    Commented Feb 18, 2016 at 17:58

3 Answers 3

Reset to default
12
$\begingroup$

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.

Improve this answer
$\endgroup$
3
  • 1
    $\begingroup$ It seems that Stellarium isn't available for Android. :( I got something called Google Sky Map instead. Will see tonight how it works. :) $\endgroup$
    – Vilx-
    Commented Mar 8, 2012 at 9:35
  • $\begingroup$ You can use google sky map for this purpose $\endgroup$
    – Sunil Kumar B M
    Commented Mar 9, 2012 at 10:22
  • $\begingroup$ NASA maintains a page to track the ISS by location: spaceflight.nasa.gov/realdata/sightings It is pretty cool to see it scooting across the sky and thinking about the fact that there are people living on that bright dot. :) $\endgroup$
    – Matt Peterson
    Commented Apr 12, 2012 at 14:10
9
$\begingroup$

The only visible satellites by the naked eye are very low in orbit. That means they are going to move very rapidly across the sky, usually in no more than 10-15 minutes, sometimes even quicker.

Also, in order for a satellite to be visible, it has to be the right time of day. It must be night on the ground, but day above the ground. This typically happens within 1-2 hours away from the sun setting/rising, when it is quite dark, but only for a few minutes.

Heavens-Above.com is my favorite source for determining if satellites are visible from the earth. From my area today, I see 19 that are brighter than 3.5 magnitude, which are easy enough to see if you are looking for them carefully.

Improve this answer
$\endgroup$
4
  • $\begingroup$ Interesting. Last summer I noticed something that fits the description, except that the sun hadn't set yet (it was evening though). And it didn't move across the horizon, it moved across the sky, almost above the head. Or, well, maybe halfway to the horizon, I don't remember very well. Perhaps it was an old satellite that was coming down. It didn't have a "tail" though, so I guess it hadn't hit the atmosphere yet. $\endgroup$
    – Vilx-
    Commented Mar 8, 2012 at 9:19
  • $\begingroup$ @Vilx: That was it, no doubt. Sky is a better choice of words than horizon, I've edited it to be more appropriate. It was probably the ISS, as that is by far the brightest object, and could well be visible in the evening. $\endgroup$
    – PearsonArtPhoto
    Commented Mar 8, 2012 at 11:45
  • $\begingroup$ Heh, interesting, I didn't know that. I thought satellites would be difficult to see from ground. Will have to check it out sometime. :) $\endgroup$
    – Vilx-
    Commented Mar 8, 2012 at 12:22
  • $\begingroup$ Ahh, the ISS seems to be passing very low near the horizon in the next few months. I probably won't be able to see it in the city unless I climb a rooftop. :( Maybe in the summer when I'm away from the city in the weekends. $\endgroup$
    – Vilx-
    Commented Mar 8, 2012 at 12:28
1
$\begingroup$

The Iridium satellites can be easily seen naked eyes. They also have flares that permit to see them even easier.

This is when the flares will happen and daily predictions for all brighter satellites.

Improve this answer
$\endgroup$
1
  • $\begingroup$ Just to clarify: Iridium flares are reflections from flat shiny surfaces on the Iridium constellation of satellites, not literal flares. $\endgroup$
    – user107153
    Commented Feb 17, 2016 at 18:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.