OK, so in ANH, Han sees the Death Star and calls it a moon. Then Obi's does the famous line, "That's no moon...that's a space station" (btw that's my favorite star wars line XD). DS1 is destroyed. Empire makes the DS2 in ROTJ, which is even bigger than its predecessor. Endor is a moon. "The Forest MOON of Endor". But if even the DS1 was considered the size of an average moon, and the DS2 is even bigger and still doesn't come close to the size of Endor, then Endor's gotta be huge! (at least for a moon...)
Good point. I had never thought about it. It must be pretty enormous. Which begs the question how big is the planet it's orbiting?
It's a gas giant, like Jupiter or Saturn. The "forest moon of Endor" would have been about the same size as Earth. The fact that it's a 'moon' refers to its orbiting a planet (as opposed to a star). Its size has no bearing on its being a moon - just as a planet could be as small as Mercury or as massive as Jupiter.
Interestingly, in the novel, the Moon had no parent planet- it had been destroyed in some cataclysm. This was retconned in later sources as "The Endor Hoax"- with it being given back its parent planet. That said, the size given for the Forest Moon of Endor in the EU is fairly consistent with existing gas giant moons- 4900 km diameter- comparable to the planet Mercury, and the moons Titan, Ganymede, and Callisto (the first two moons are larger, the third smaller). It is not, however, consistent with the size estimated for the Death Star 2- 900 km diameter- much larger relative to the Forest Moon, than it appears in any of the movie scenes. I lean to the view that this was an overestimate.
That pic was in Illustrated Star Wars Universe- can't remember if it was in the movie. Maybe the Ewoks movies?
Well, in the same conversation Luke sees the DS1 first and says:'Lets land on that small moon."So that means the DS2 can't be much larger. In our own solar system the differences are sometimes even larger.
Not in the most recently printed source, The Essential Atlas- which gives its diameter as 4900 km. The DS2 is, in the novel "nearly twice as big" as the DS1- but as it currently stands, the diameters given are 160 km and 900 km- horribly different from the novel version.
Wookieepedia says diameter of 4900 km, and a gravity of 85% of standard, which meants it's about 85% the size of Earth (yes Earth is the standard for that).
Strictly it's quite a bit less than 85% of the diameter, and a planet that size with 85% Earth's gravity, would have a lot less than 85% Earth's mass. This is because surface gravity is inversely proportional to radius. When reading an article about hypothetical planets with different compositions to Earth, and what size they'd compress to under their own gravity, the sample 1 Earth-mass "pure iron planet" caught my eye- because its diameter was 4800 km- slightly less than the Forest Moon's. Such a planet, thanks to its small size, would have a surface gravity several times that of Earth. Conclusion- one only needs to lower the proportion of iron to rock a bit- to produce something like the Forest Moon- small, yet with near-normal gravity.
Mass doesn't equal size. Mass is the amount of material in a particular object. It's based on the molecular contents of what makes up the object. Our sun will become a white dwarf roughly the size of Texas after all is said and done. It's core would be of pure carbon compressed to an intensely compressed daimond state. If you were to place one sugar cube sized amount of that white dwarf on the Earth's surface, it would be so heavy (read: massive) that it it would sink immediately to the Earth's core. Earth's diameter is on average 12,742 km. Mars (from wikipedia): Mars has approximately half the diameter of Earth. It is less dense than Earth, having about 15% of Earth's volume and 11% of the mass. It's diameter is 6,752 km. Gravity is directly related to mass. So 85% of the Endor moons mass equals mass of Earth. If that is so, it should be a bit smaller than Mars. Which is significant in this discussion. However... keen eye pointing that out, Iron_Lord... made me put my brain to work . So I suppose the GFFA is doing well with keeping Endor at a moon size. And there you go Good job!
After looking it up, and doing the calculations, I've worked out the following. 1 Earth-mass pure iron planet's diameter is 3000 miles or 4800 km: http://www.astrobio.net/pressrelease/2476/all-planets-possible Forest Moon's diameter is 4900 km (The Essential Atlas) Earth's diameter is 12756 km (equatorial) Forest Moon's diameter (and radius) is 0.384 x that of Earth. 1 earth-mass pure iron planet's radius is 0.376 x that of Earth. Using the simple formula for surface gravity here: http://en.wikipedia.org/wiki/Surface_gravity A planet with a radius 0.384 x that of Earth (Forest Moon) with a surface gravity 85% of Earth's, would be 12.5% of Earth's mass, and 2.2 x as dense as Earth. The pure iron planet's density would be 18.77 x that of Earth, and its surface gravity would be 7.06 x that of Earth. EDIT- however, if the writer of the article messed up and used diameter where they should have used radius (so diameter 6000 miles or 9600 km) the density would be 2.34 x that of Earth and the surface gravity would be 1.77 x that of Earth.
