OK, this is getting unsettling.

In the 1990s, astronomers started revealing with just about total confidence that they were spotting planets orbiting around other stars — an idea they had dodged talking about for decades. The first one identified with “unambiguous proof” was orbiting a pulsar, PSR 1257 + 12, announced in 1992.

The instruments got better, and more exoplanets were added to the list. In 2009, the Kepler Space Telescope was launched. Its primary mission is to spot planets by collecting and analyzing the behavior of a star’s light.

So many planets have since been added to the list that astronomers now state as a fact that most stars — 100 billion or more stars in the Milky Way galaxy, plus the stars in 200 billion or more other galaxies — have planets of one kind or another orbiting them.

The more planets there are, the greater the possibility of extraterrestrial life.

Along the way, that line of inquiry has also expanded. In 1996, some NASA and academic researchers boldly suggested that some wormy-looking forms in a meteorite that broke off Mars and then landed in Antarctica 16 million years ago are probably fossils of ancient Martian life. Not everyone bought this claim.

But at the same time, creeping into the planetary science papers has been more and more open enthusiasm for the idea that oceans underneath the ice surfaces of Jupiter’s moon Europa and Saturn’s moon Enceladus could have the right conditions to support living organisms. NASA officials unabashedly announced last month they were sending the Cassini spacecraft, which has been orbiting Saturn since 2004, through Enceladus’ geysers to gather evidence one way or the other. They’ll let us know in a year or so what they find out.

On Saturn’s largest moon, Titan, certain characteristics of its atmospheric chemistry may imply methane-based biological processes are at work. On Mars, newly noticed evidence of recently running water has pumped up speculation that things could be living in it.

Meanwhile, a few years ago the eminent astrophysicist Stephen Hawking admonished those conducting formal searches for extraterrestrial intelligence, or SETI, that sending signals out to attract the attention of technologically advanced extraterrestrial cultures is probably a dangerous move because it assumes the putative aliens are well-intentioned, which they may not be. Then this summer, Hawking tacked off his warning and joined what will become the largest SETI project ever. He and his $100 million investor, Yuri Milner, obviously have reasons to think there’s something out there to find.

Hawking and Milner are not alone. A recent entry in a long line of SETI projects is UFODATA, organized in connection with the Center for UFO Studies and including well-credentialed scientists. It will conduct formal research into the UFO phenomenon, which is itself a well-documented reality whose central question — what are UFOs? — no one has answered. Yet.

In September, a team of researchers published a study, using data gathered with the Kepler telescope, explaining that extremely unusual behaviors of light coming from star KIC 8462852 in the constellation Cygnus are extremely difficult to account for by natural events. The lead scientist then went to SETI researchers with the findings to try out the idea that the unusual light behaviors might result from artificial structures, such as Dyson spheres (which are hypothetical energy-gathering satellites), orbiting a planet.

And as if all that isn’t enough, NASA held a news conference in April to announce their prediction that they’ll have “definitive evidence” of extraterrestrial life within 20 to 30 years. They want us to gather that they’re talking about microbes.

These developments among establishment scientists are starting to overshadow the more shadowy work of people like, for example, my colleague in really-what-the-hell-is-going-on-here, Enterprise Mission chief Richard Hoagland, who has been expansively adamant for decades that there are ancient ruins on Mars, the remains of invisible buildings on the moon, and an arcane cover-up of extraterrestrial contact.

What, exactly, is going to be divulged to us within the 20 years predicted by the NASA scientists? I don’t know, obviously, but the Hoagland-fascinated side of me is starting to wonder if it has not been decided (by whom, exactly?) that we as a culture have matured beyond the xenophobia described in the 1960 Brookings Report that advised the government to be very careful of what it said about ETs because our reaction could be destabilizingly bad.

Every time I wander onto this unsettling topic, I recall a footnote toward the end of Edgar Mitchell’s book “The Way of the Explorer.” Mitchell, you may recall, is an MIT graduate, an Apollo 14 astronaut, and, following the visionary experience he had in the space capsule on the way back from the moon, a philosopher of physical and noetic sciences. He wrote in his book — which is a lengthy summary of his trip to the moon and the ideas that developed afterward — the following footnote: “I’ve had no personal encounters with UFOs. … I have, however, met with credible professionals within two governments who have testified to their own firsthand experiences with ‘close encounters’ during their official duties.”

This summer I posed a question to Richard Grossinger, of Portland, who has copious academic and firsthand knowledge of everything from astronomy and astrology to the Enterprise Mission to the anthropology of bardo traditions. I asked if it seemed to him like the administrative echelons were getting ready to let us in on some X-Files-like secret involving knowledge about alien life that has not yet been, well, discussed publicly.

“Some people think so,” he said.

I’m not saying I’m one of them. I’m just describing what I can see from my backyard.

Dana Wilde lives in Troy. He is a contributor to “Pluto: New Horizons for a Lost Horizon,” which is available from North Atlantic Books. You can contact him at [email protected] Backyard Naturalist appears the second and fourth Thursdays each month.