 Greetings and welcome to the Introduction to Astronomy. In this week's Misconception in Astronomy, we are going to look at stars, and especially stars in constellations, and find out if they are really close together in space or not. So let's take a look at this, and are stars in constellations close together in space, and the answer is very emphatically no. Stars are actually at widely varying distances. So when we look at something like the constellation of Ursa Major, some of these, we see in the image here, some of these stars are close together in space, and in fact most of the stars within the dipper itself are relatively close together. However, you can find other objects there within that constellation, and even parts of those parts of the constellation itself, that are widely varying. What is a constellation? It is defined to be a very specific region of the sky, and these were set by the International Astronomical Union nearly a hundred years ago. They are two-dimensional, not three. So a constellation would not look the same from other parts of the galaxy. If you were to travel out hundreds or thousands of light-years, you might pass some stars in a constellation, and you might not pass others. Stars could be on multiple different sides, and you would see a completely different view. Now that doesn't affect us here in the solar system, because we can't travel far enough. You would need to be going hundreds of light-years away. Now let's look at a couple of examples of this to get a better idea of what we mean. So let's first look at the constellation of Orion. Now in the constellation of Orion, we have several bright stars, including the star Betelgeuse, which is the bright red star up to the upper left, and then we have the star Rigel, which is to the lower right here, and then we have the star Altenac, which is the star in the edge of the belt. Now these are at various different distances from each other. They are not at the same distance. And in fact Betelgeuse is about 550 light-years away. Rigel is 800 over 800 light-years away, and Altenac is actually over a thousand light-years away, twice the distance of Betelgeuse. So when we look at those there, we can see them together in the sky. They look like they are all together. But if you were to travel out, say 800 light-years toward Rigel, then one of the star's Betelgeuse would be on one side of the sky, and Altenac would be on the other side of the sky. You wouldn't have reached that yet, but you would have passed Betelgeuse. So if you traveled out in the direction of Orion, that would be one example here. Let's look at one more just to clarify this, and let's look in this case at the constellation of Cygnus the Swan. And we're just going to look at two stars here specifically. And which ones are we looking at? Well, we are going to look at the stars Denib and Delta Cygni. Now let's take a look. Where are these located in the constellation? Well, Denib is labeled here for you, and Denib is right here. And Denib is over 2,500 light-years away. Delta Cygni is actually not labeled, but is this star right here. Now what is that? Delta Cygni is only 100, 165 light-years away. So these two stars, even though they're very close to each other in the sky, and very close within the same constellation, not appearing very far apart, are at vastly greater distances. Denib is more easily more than 10 times more distant than Delta Cygni. So when we look at a constellation, we have to consider that the stars are really at widely varying distances. So let's summarize what we've looked at here. What is a constellation? Well, a constellation is a grouping of stars in the sky. They are not necessarily related to one another. They may not be together in space. And that stars in that same constellation can be located at widely varying distances from each other. So that concludes this misconception in astronomy on the stars in a constellation being close together. We'll be back again next time for another topic in astronomy. So until then, have a great day, everyone. And I will see you in class.