If intelligent aliens visit the Earth, it would be one of the most profound events in
human history.
Surveys show that nearly half of Americans believe that aliens have visited the Earth,
either in the ancient past or recently.
That percentage has been increasing.
Belief in alien visitation is greater than belief that Bigfoot is a real creature, but
less than belief that places can be haunted by spirits.
Scientists dismiss these beliefs as not representing real physical phenomena.
They don’t deny the existence of intelligent aliens.
But they set a high bar for proof that we’ve been visited by creatures from another star
system.
As Carl Sagan said, “Extraordinary claims require extraordinary evidence.”
Dr. Chris Impey, the author of this story, is a professor of astronomy who has written
extensively on the search for life in the universe.
He also teaches a free online class on astrobiology.
UFO means unidentified flying object.
Nothing more, nothing less.
There’s a long history of UFO sightings.
Air Force studies of UFOs have been going on since the 1940s.
In the United States, “ground zero” for UFOs occurred in 1947 in Roswell, New Mexico.
The fact that the Roswell incident was soon explained as the crash landing of a military
high-altitude balloon didn’t stem a tide of new sightings.
The majority of UFOs appear to people in the United States.
It’s curious that Asia and Africa have so few sightings despite their large populations,
and even more surprising that the sightings stop at the Canadian and Mexican borders.
Most UFOs have mundane explanations.
Over half can be attributed to meteors, fireballs, and the planet Venus.
Such bright objects are familiar to astronomers but are often not recognized by members of
the public.
Reports of visits from UFOs inexplicably peaked about six years ago.
Many people who say they have seen UFOs are either dog walkers or smokers.
Why?
Because they’re outside the most.
Sightings concentrate in evening hours, particularly on Fridays, when many people are relaxing
with one or more drinks.
A few people, like former NASA employee James Oberg, have the fortitude to track down and
find conventional explanations for decades of UFO sightings.
Most astronomers find the hypothesis of alien visits implausible, so they concentrate their
energy on the exciting scientific search for life beyond the Earth.
While UFOs continue to swirl in the popular culture, scientists are trying to answer the
big question that is raised by UFOs: Are we alone?
Astronomers have discovered over 4,000 exoplanets, or planets orbiting other stars, a number
that doubles every two years.
Some of these exoplanets are considered habitable since they are close to the Earth’s mass
and at the right distance from their stars to have water on their surfaces.
The nearest of these habitable planets are less than 20 light-years away, in our cosmic
“back yard.”
Extrapolating from these results leads to a projection of 300 million habitable worlds
in our galaxy.
Each of these Earth-like planets is a potential biological experiment, and there have been
billions of years since they formed for life to develop and for intelligence and technology
to emerge.
Astronomers are very confident there is life beyond the Earth.
As astronomer and ace exoplanet-hunter Geoff Marcy, puts it, “The universe is apparently
bulging at the seams with the ingredients of biology.”
There are many steps in the progression from Earths with suitable conditions for life to
intelligent aliens hopping from star to star.
Astronomers use the Drake Equation to estimate the number of technological alien civilizations
in our galaxy.
There are many uncertainties in the Drake Equation, but interpreting it in the light
of recent exoplanet discoveries makes it very unlikely that we are the only, or the first,
advanced civilization.
This confidence has fueled an active search for intelligent life, which has been unsuccessful
so far.
So researchers have recast the question “Are we alone?”
to “Where are they?”
The absence of evidence for intelligent aliens is called the Fermi Paradox.
Even if intelligent aliens do exist, there are a number of reasons why we might not have
found them and they might not have found us.
Scientists do not discount the idea of aliens.
But they aren’t convinced by the evidence to date because it is unreliable, or because
there are so many other more mundane explanations.
UFOs are part of the landscape of conspiracy theories, including accounts of abduction
by aliens and crop circles created by aliens.
But it's highly unlikely that intelligent beings with vastly superior technology would
travel trillions of miles just to press down our wheat.
UFOs have become a kind of new American religion.
Belief in UFOs is not crazy, because some flying objects are unidentified, and the existence
of intelligent aliens is scientifically plausible.
But a study of young adults did find that UFO belief is associated with schizotypal
personality, a tendency toward social anxiety, paranoid ideas, and transient psychosis.
If you believe in UFOs, you might look at what other unconventional beliefs you have.
Before ending the story, Dr. Impey recalls the aphorism popularized by Carl Sagan, “It
pays to keep an open mind, but not so open your brains fall out.”