dipper@utastro.UUCP (Debbie Byrd) (05/22/85)
You'd have to travel very far away from Earth before the constellations would begin to look different. More -- after this. May 22 How to Change a Constellation Listeners sometimes write to ask if the constellations would look the same from other worlds in our solar system as they do from Earth. The answer is that they would. They'd look the same from the innermost world, Mercury, to the double world Pluto and Charon -- which generally move on the outer fringes of the solar system. The constellations are just patterns of stars. They'd look the same throughout our solar system because the distances between planets in our sun's family are tiny compared to the vast distances between stars. You'd have to travel very far away from Earth before the constellations would appear to change from the patterns we know. Even the distance to the next-nearest star wouldn't be far enough. That star is Alpha Centauri. It's about four light-years away. Even from Alpha Centauri, the same familiar constellations that we see from the surface of Earth would be visible. But from there, our sun would appear as a star somewhere in the Alpha Centaurian sky -- and Alpha Centauri itself would appear as a sun -- as would the two sister suns to Alpha Centauri in that triple system of stars. You'd have to travel fifty or a hundred light-years away for the constellations to begin to look very different. Then we'd still see many of the same stars that we know in our sky. But they'd form different patterns because our vantagepoint on them would be different. And they'd appear different brightnesses from what we see -- since their light would travel to us over greater or lesser distances. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin