<b>I am curious about where our sun/planetary system fits into the universe.</b><br /><br />Excellent! Curiosity is a wonderful thing, and space is certainly a good place to indulge it. <img src="/images/icons/wink.gif" /><br /><br /><b>Is our sun a part of any known star system? By using astronomy software it appears we could be part of alpa centauri.</b><br /><br />There is no known gravitational connection between the Sun and Alpha Centauri, so no, it is not in the same star system as Alpha Centauri (which is also known as Rigil Kentaurus, incidentally). Our solar system, by all accounts, is a single-star system.<br /><br /><b>Also is our sun a star in any known constellation?</b><br /><br />No. The constellations are artificial constructs made up by astronomers through the millenia to map the sky so they could talk about it with one another. They consist only of the "fixed stars" (the stars that didn't seem to move obviously in the sky to an early astronomer, and which were too far away for the distance to be measured until the 19th Century). The Sun does seem to pass through various constellations over the course of the year (as a consequence of the Earth moving around it). The twelve constellations it passes through are called the Zodiac, and astrologers have for millenia made certain conclusions based on where the Sun and the planets are in the Zodiac.<br /><br /><b>How would the earth appear to someone on venus or jupiter (I am thinking in terms of illumination/brightness)?</b><br /><br />Earth should be pretty bright from Venus, especially if it is near opposition (Sun-Venus-Earth all lined up). But it won't be so bright from Jupiter, and will tend to be drowned out by the Sun a lot of the time. Jupiter is much farther away from Earth than Venus is.<br /><br />I'm not sure what apparent magnitude Earth will have, though. It is not as reflective as Venus, but when Venus and Earth are lined up on the same side of the Sun, Earth will be "full" , whereas from Earth, Ve <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>