After fooling around the little colored planet with the Green Lumas in The Observatory.
I found out that you can exit the gravitational pull of the planet by either doing a Triple Jump + Air Spin, or Use the Homing Stomp on the Green Lumas.
After that I thought of using the Green Lumas to land back on The Observatory by being launched there using my Homing Stomp, after a lot of tries I managed to land on the Mushroom Spaceship after falling off so many times.
After I finally did it, I saw the Red Star, and thought if I could use it on the Planet, I had an idea of using the 'Fall off the planet and get sent back thing' to do it.
I broke the Glass Crystal thing holding the Red Star, and then went to the Planet. Now I had to try to launch myself near the Red Star using the Green Luma in the middle of the planet.
*Can only get that Green Luma after collecting 120 Stars with both Mario and Luigi*
I had to land at the very edge of the platform with the Red Star, or else if I fell off I'd be sent back to that same platform rather then the Planet.
After about 50 Tries, I finally did it!
I got the Fly Ability *Red Star*, jumped off, and was sent to the Planet WITH the Ability.
Then that's when I found out your Air Spin was disabled, you couldn't do it.
Without the Air Spin, you can't fly.
NOTE: Watch at 3:16, Notice how Luigi did an Air Spin, but didn't fly! I guess this proves that They disable fly if used anywhere else besides the planet you got it on.
Thanks to that, we can't fly around there, and if we were able to fly, I am pretty sure we could fly far away from The Observatory unless there was another Barrier to prevent you from going any further from The Observatory.