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.

Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard.