"This wormhole has not yet begun its natural cycle of decay and should last at least another day." means 24+ hours

"This wormhole is beginning to decay, and probably won't last another day." means under 24 hours

"This wormhole is reaching the end of its natural lifetime." less than 4 hours, not verified.

"This wormhole is on the verge of dissipating into the ether." -- not sure the timer