Why Would It Be Impossible To Land A Spaceship On Jupiter, Saturn, Uranus, Or Neptune And Then Blast Off Again?

Because they are gas planets, they dont have a surface in which you could land on. By the time you make the ground on one of these planets you will be crushed by the pressure of the atmosphere.
Because they are all gas planets with no solid surface until you reach the core.

Resolved Questions:
What does platte mingy?
In geology terminology, Platte refers to a resistant knob of rock which is found in a glacial vale, or rising in the middle of a glacier that already exists. Such a substance is frequently responsible for causing the glacier to split into two near the snout. Platte is also a...

How do you find the crazy suit within Tony Hawks American Wasteland?
There are two types of suits in Tony Hawk's American Wasteland. One is the Panda Suit and the other is the Alien Suit. You can buy the Panda suit in the Classic mode or the Free Skate mode. You can buy the suit...

How Do You Make Molten Glass?
Extremely high heat ;) I've only done it once, but second summer on a camping trip we had a very big fire and we very carefully placed a couple beer bottles in the coals. I'll attempt to upload a pic of it here ;)