matthew, on the one hand, the searchers must be very encouraged by hearing the pings this weekend. on the other hand, by many estimates, the batteries in the pinger should have already run out. do they feel like they're closing in? >> reporter: yeah, i think there's a sense, or the at least there was 24 hours ago, when this announcement was made, that they're making good progress. of course, they're being very cautious, saying that they haven't found the aircraft yet. but they did describe these two separate acoustic events, the detection of these pings, under the surface of the indian ocean, as, you know, the best evidence they have, the best clue they had, the best lead they had, i think was the word they used, going forward. much more optimistic yesterday than they were a week ago, with the words of angus houston, the official who's heading up the multi-national search teams. but there's going to be a news conference here over the course of the next hour with the australian defense minister. he'll be giving a statement as well, after meeting with base officials and meeting with the