Over the last two days, bloggers at a few of the country’s top news outlets have engaged in wild and wholly unsubstantiated speculation about the discovery of alien life.

The runaway blogging stems from a cryptic press release issued by NASA on Monday, which said that the agency would be holding a news conference at 2 p.m. on Thursday “to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.”

The press release immediately provoked rumors online that scientists had discovered some form of alien life. Lest anybody start breaking out welcome signs for the mother ship or donning tinfoil hats, however, it is important to note straightaway that they have done no such thing. Moreover, the episode highlights the pitfall of jumping to conclusions in the fast-paced, modern media.

NASA’s press release is based on an upcoming paper in Science Express (embargoed until 2 p.m. Thursday) and noted that the paper’s lead author, Felisa Wolfe-Simon, would be one of a handful of scientists participating in the news conference.

Independent blogger Jason Kottke got the speculation ball rolling after he looked up the conference participants and found that they had variously worked on geology and life on Mars, photosynthesis using arsenic, the chemical environment on Titan (Saturn’s largest moon), and the chemistry of environments where life evolves.

“So, if I had to guess at what NASA is going to reveal on Thursday,” he wrote in a Monday post, “I’d say that they’ve discovered arsenic on Titan and maybe even detected chemical evidence of bacteria utilizing it for photosynthesis (by following the elements). Or something like that.”

Seizing on Kottke’s hypothesis, The Atlanta Journal Constitution published a post of its own on Tuesday, reporting that “Speculation is growing that NASA has discovered life on one of Saturn’s moons.” Later that day, The Washington Post’s Celebritology blog weighed in with an admittedly tongue-in-cheek post noting that extraterrestrial life has provided “never-ending fodder for countless movies, books and long-running TV shows … Because, until now, there’s been no real proof of alien life elsewhere in the known universe (no matter what Mick Jagger says). Come Thursday, that may change.”

To some extent, CBS News attempted to extinguish the flames of speculation, but more likely ended up fanning them in a post reporting that:

A seemingly routine press release issued by NASA is causing a serious stir in the blogosphere today with no small amount of hyperventilation about the possibility that scientists may have something to say about the discovery of extraterrestrial life…

Of course, more than a little skepticism is called for since at this point nobody outside of NASA knows what’s on tap for Thursday. Given the advance hype, however, anything less than a cameo by ET will likely come as a disappointment to many. Still, space exploration continues to proceed on a steady pace and so even if it’s not the aforesaid blockbuster, the announcement will be worth watching.

Fortunately, a few more responsible science reporters quickly stepped into the fray in an effort to stop the guessing games.

“I’m sad to quell some of the @kottke-induced excitement about possible extraterrestrial life,” Atlantic senior editor Alexis Madrigal wrote in a tweet early Tuesday morning. “I’ve seen the Science paper. It’s not that.”

Posts at MSNBC.com’s Cosmic Log blog, Discover’s Bad Astronomy blog, and at the independent NASA Watch blog also tried to quell the otherworldly hysteria. (Further efforts have since appeared at the Associated Press and Time.)

Indeed, the embargoed Science paper, which I have also seen, is quite terrestrial in nature and will come as a disappointment to those breathlessly waiting for news that E.T. has phoned home. It’s an interesting piece of research, but certainly not one that is bound to make the front page, or perhaps any page. One science reporter I talked to (who’s also seen the paper, but didn’t want to comment on the record) felt that it was “actually quite dull.”

Regardless, the runaway speculation in the blogosphere imperils the work of trusted science reporters who respect the embargo system and may have wanted to cover the paper. Most professional science journalists have access to Science’s embargoed papers through the EurekAlert! service run by AAAS (which publishes Science) and would have been able to easily figure out that the research behind NASA’s cryptic press release did not support the hype about aliens.

“This shows how important an experienced, trained and authoritative science journalism staff of reporters and editors is,” AP science reporter Seth Borenstein wrote in an e-mail, responding to questions about the blog frenzy. “While the blogosphere has the luxury of speculating, The Associated Press seeks to be the definitive source through careful reporting and knowledge of the subject area.

“In this case it would take about two minutes to get it right. The actual story is not nearly as sensational as what’s being reported in the blogosphere. As a reporter who has covered astrobiology for more than a decade, I can tell you it has nothing to do with little green men or anything alien. Astrobiology is a series of little steps on Earth and beyond. Experienced science reporters know how to interpret the press release that got the speculation going. There is still a place for solid journalism.”

The problem is that in today’s fast-paced, modern media world, online press releases can get picked up by those without access to EurekAlert! and go viral long before the embargo is up. That problem has not escaped the people at AAAS, which sent a special note on Wednesday morning to all journalists who receive its embargoed press releases.

“A number of journalists have contacted the [AAAS press] office with questions about the Science embargo after seeing mostly erroneous online and/or tabloid speculation about the forthcoming research,” the e-mail said. “These reports clearly are not based on the peer-reviewed research being published under the auspices of the journal Science.”

Nonetheless, AAAS decided that the speculation was not sufficient reason to lift the embargo early. The AP’s Borenstein also defended the system.

“While the embargo system may have issues, I embrace it because it gives us a chance to provide context, outside comment and above all get it right,” he wrote in an e-mail. “In this hectic media environment, more than ever the world needs science reporters and editors who understand what’s happening, can tell fact from speculation, put phrases in context, be definitive and above all get it right. This whole sorry affair provides the proof of that.”

That may be so, but the question remains: Can anything be done to discourage misinformed, runway blogging that can lead to so much public confusion? In his post for Discover, Bad Astronomy’s Phil Plait noted that he didn’t have any concrete solutions, but that faulty press releases have created problems many times in the past.

“I don’t want to blame anyone,” he wrote, “but I do sometimes wish the press folks at NASA were more aware of what kind of cascade a line like [the one about extraterrestrial life] provokes (like the one from a few weeks ago which said it was about “an exceptional object in our cosmic neighborhood” but it turned out to be a supernova/black hole 50 million light years away). When announcements like these go public, it’s bound to be disappointing when the actual news gets out and it’s not a black hole right next door or actual life on Mars.”

That, Plait said, can lead to “news fatigue.” It can also erode trust in science and journalism. Understanding that, the only hope may be that all sides—scientists, press officers, and journalists alike—will tread more carefully. Scientists and press officers need to avoid cryptic yet proactive news releases. And journalists (as well as amateur bloggers) must resist the temptation to jump to conclusions without first checking their facts.

[Update, Dec. 8: Embargo Watch’s Ivan Oransky got the following response from Dwayne Brown, senior public affairs officer in the office of communications of the NASA Science Mission Directorate, when he asked if the agency regretted using the phrase “extra-terrestrial” in its initial press release:

“It’s easy to play Monday morning quarterback. However, the statement was accurate.

“The real issue is that the reporting world has changed because of the Internet/bloggers/social media, etc. A “buzz” term like ET will have anyone with a computer put out anything they want or feel. NASA DID NOT HYPE anything - others did. Credible media organizations have not questioned NASA about any text. Bloggers and social media have……..it’s what makes our country great—FREEDOM OF SPEECH.

“The discussion now is about the science and next steps.”

Calling the press release accurate relies on a technicality, however. A statement can be factually correct and misleading at the same time, due to ambiguity, tenor, or a dozen other rhetorical factors. Moreover, “pitting” (as Oransky put it) blogs against “credible media organizations” belies the fact that blogs at The Washington Post, The Atlanta Journal Constitution, and CBS News were among those that fed the speculation about aliens.]

Curtis Brainard is the editor of The Observatory, CJR's online critique of science and environment reporting. Follow him on Twitter @cbrainard.