In the year 2000 a written note with Jack O'Neill's handwriting and blood emerged from Earth's Stargate reading: "Under no circumstances go to P4C-970. Colonel Jack O'Neill." Unknown to the SGC, the note was sent from the year 2010 in an alternate timeline in which the Aschen covertly sterilized Earth's population. Gen. Hammond subsequently declared the planet off limits to the SGC and its address was locked out from the planetary database and all contact with it was forbidden. (SG1: "2010")
Later, in the year 2001 SGC made contact with the Aschen through the Volians, which were a primitive farming society. Initialy, an alliance was to be formed, but when it was discovered that the Aschen would devastate Earth with a biological weapon, causing sterility, concealed as a vaccine, the negotiations were dropped and The Aschen delegation attempted to send a biological weapon to Earth, however, they closed the Iris in time.
The ambassador of earth had previously presented them with a "gift" of stargate addresses, which would enable the Ashen to dial other gates than the ones not effected by stellar drift. However, the addresses contained dangerous and or useless worlds as one being a black hole and others which "gets progressively darker" as described by Jack O'Neill.(SG1: "2001")
By 2004, Aschen Prime was assumed destroyed by a black hole, likely the one near P3W-451, allthough it is not confirmed that they ever dialled the address or did not find a way to close the gate. (SG1: "Relativity")