Usually a British or Irish term. It means something Extremely good or appealing. Heres an explanation of the words
Slice- as in a slice of pie, which is very appealing
Fried - Everyone loves fried food
Gold - Fuck, who doesnt love gold?
So, therefore, Slice of fried gold means something that when you see it, you melt in your pants

The safeguarding of Earth and other worlds from biological cross-contamination (i.e. billionaires with too much time on their hands).

Also known as “planetary protection.” Planetary protection / quarantine “reflects both the unknown nature of the space environment and the desire of the scientific community to preserve the pristine nature of celestial bodies until they can be studied in detail.”

There are two types of interplanetary contamination. Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth's biosphere.