Sometimes, when thinking about space, we just use the word star in general and we just think of stars, but there are many different types of stars. We’re going to take a look at some of those. One is the main sequence star. Most stars are main sequence stars, so the majority of stars are main sequence stars.
This is just your normal star and you may not know that the sun is actually a star, it just happens to be so close to Earth, so it provides us with heat. The sun is a main sequence star.
The transcript is for your convenience.
Then we have red super giants, that’s another type and a star that you’re familiar with that’s a red super giant, is Betelgeuse, which isn’t really spelled like you think Betelgeuse would be spelled but has the same pronunciation. To give you an idea of how big these types of stars are, I’m going to kind of provide a kind of analogy, some other types of stars and it gets you the white dwarf and the red dwarf and right here I have the sun, which is a kind of an example that’s representing main sequence stars in general.
If the sun were the size of dime, then Betelgeuse would be about three meters short of being the size of a football field including both end zones. This end zone is only three meters off, we’ll say it’s the size of a football field. Now white dwarf would be the size of small bacterium and red dwarf would be about the size of a sesame seed. I kind of just number these in order right here, so football field is obviously the largest, then we go to dime, then the sesame seed and then the small bacteria.
You have an idea of the relative size here and so the sun and then red dwarf are somewhat similar in size, but a small bacterium is extremely small and then a football field is extremely huge, even compared to a dime. To kind of attach some actual number figures to this, the sun is about one point four kilometers in diameter, then Betelgeuse is about 825 million kilometers in diameter, it’s located about 640 light-years from the sun.
In fact if Betelgeuse was located in the same place as the sun, it would extend past the orbit of Jupiter. If you think about where the sun is and then you think about the other planets and you know where Jupiter is, Betelgeuse would take up all of this area, that’s how large it is, it’s really huge.
Now the largest known star which is the hypergiant Vy Canis Major is over three billion kilometers in diameter Rember that earlier I said the sun is about 1.4 million kilometers in diameter. Well, Vy Canis Major is over 3 billion kilometers in diameter. and it’s located about 4900 light-years from earth. Most red giants are considerably smaller than Betelgeuse or Vy Canis Major, but are still 25 to 50 times the diameter of the sun.
Think about the sun being really huge to provide all that heat to the earth, but really the sun is extremely small when compared to most stars or maybe not most stars, because main sequence stars are the larger kind of star, but the sun is extremely small when we compare it to other stars that are out there.