This wormhole has not yet begun its natural cycle of decay and should last at least another day (More than 24 hours remaining)

This wormhole is beginning to decay, and probably won't last another day (Less than 24 hours left, more than 4 hours left)

This wormhole is reaching the end of its natural lifetime (Less than 4 hours left, generally don't go through these ones unless you know the exact EOL - Which means End Of Life)

(Never seen this one, but according to UniWiki it exists, so..) This wormhole is on the verge of dissipating into the ether (Apparently, minutes before it collapses, DO NOT go through under any circumstances, it will definitely close behind you.)