How to Identify that Light in the Sky
What is that light in the sky? Perhaps one of humanity's more common questions, an answer may result from a few quick observations. For example -- is it moving or blinking? If so, and if you live near a city, the answer is typically an airplane, since planes are so numerous and so few stars and satellites are bright enough to be seen over the din of artificial city lights . If not, and if you live far from a city, that bright light is likely a planet such as Venus or Mars -- the former of which is constrained to appear near the horizon just before dawn or after dusk. Sometimes the low apparent motion of a distant airplane near the horizon makes it hard to tell from a bright planet , but even this can usually be discerned by the plane's motion over a few minutes. Still unsure? The above chart gives a sometimes-humorous but mostly-accurate assessment. Dedicated sky enthusiasts will likely note -- and are encouraged to provide -- polite corrections. Poll: Is APOD a Blog?