So what’s the press conference about? I don’t know, to be honest, beyond what’s in the announcement. The scientists on the panel are interesting, including noted astrobiologists and geologists who work on solar system objects like Mars and Titan. So this is most likely going to be something about conditions on another moon or planet conducive for life.
Of course, the speculation is that NASA will announce the discovery for life. Maybe. I can’t rule that out, but it seems really unlikely; I don’t think they would announce it in this way. It would’ve been under tighter wraps, or one thing. It’s more likely they’ve found a new way life can exist and that evidence for these conditions exists on other worlds. But without more info, I won’t speculate any farther than that.
As for the public reaction, well, we’ve seen this type of thing before. Just last June, JPL had a press release about a surprising lack of acetylene in Titan’s atmosphere, with the title "What Is Consuming Hydrogen & Acetylene on Titan?" That sparked vast speculation, and even though the press release was clear enough
it was misleadingly reported as NASA finding signs of life on Titan. It got so silly that I wound up
writing a post about it, and a NASA scientist went so far as
to write an article to clear up the rumors of life on Titan.
I can’t really blame NASA, the press outlets, or the public about this. When scientists have newsworthy findings that are published in a journal, there may be a press conference about them. But some journals have embargoes; they don’t want the news released until the issue is published. Fair enough. So NASA schedules a press conference for the time the issue publishes, and sends out a notice to the press about it. I got just such an email for this one, for example. They have to say something in the email so the press can decide whether to cover it or not, and NASA doesn’t want give too much away. So they give some minimal line about findings that’ll have an impact on the search for life, and those of us who’ve dealt with it before know what that means.
But the public is naturally more inclined to interpret that line as NASA having found life, or at least solid evidence of it. That’s not surprising at all. But it can lead to "news letdown", where the reality is something less than the speculation. And that leads to news fatigue, which is worse. If people keep expecting really exciting news and don’t get it, well, there you go.