by Patrick Huyghe
In late 1991, astronomers may have detected an
extraterrestrial space probe in near Earth space. Who makes such a
startling statement? Some wild-eyed UFO believer? A renegade scientist?
A tabloid psychic? No, not at all. His name is Duncan Steel.
Who is Steel, you wonder? I'll quote from the
jacket of his new book, Rogue Asteroids and Doomsday Comets
(Wiley, 1995): "Duncan Steel, Ph.D. is a research astronomer at the
Anglo-Australian Observatory and a research fellow at the University of
Ad elaide, Australia. A world renowned authority on the comet, hazard,
he has served on both the Detection Committee and the Intercept
Committee created by NASA to assess the threat of comet and asteroid
collisions and investigate technologies to avert such impacts." Not
only that, but Steel is thought of as a "longtime skeptic" and "as
someone who almost invariably has his facts right," according a
reviewer in an Australian magazine (Colin Keay in The Skeptic,
Vol 15, No.3, 1995).
So how did Steel come to his startling
conclusion? Here's the scoop. On Nov. 6, 1991 Jim Scotti using the Spacewatch
telescope at Kitt Peak in Arizona discovered a body which he initially
described as a "fast moving asteroidal object," a month befo re its
closest approach to the Earth. Later, the object's heliocentric orbital
elements suggested instead that "the object might be a returning
spacecraft." As the approximately 30-foot object, now labeled 1991 VG,
neared the Earth, astronomers at the Eur opean Southern Observatory
tracked it and found strong, rapid brightness variations suggestive of
reflections from a rotating spacecraft.
His curiosity piqued, Steel decided to
investigate the different probabilities for the nature of this object,
according to his account "SETA and 1991 VG," published in The
Observatory (Vol. 115, pp. 78-83, 1995). "SETA," by the way, stands
for "Search for Extra-Terrestrial Artifacts" within our Solar System.
Steel first wondered whether the object could be a returning
spacecraft, given those brightness variations and its very Earth-like
orbit. But he found that none of the handful of man-ma de rocket bodies
left in heliocentric orbits during the space age have purely
gravitational orbits returning to the Earth at that time. Besides, if
1991 VG was a man-made rocket body, then its return to our vicinity and
its accidental detection by Spacew atch was, Steel calculated, a very
unlikely event, on the order of one in 100,000 per year.
So could it be a natural body, Steel then asked
himself? One factor that strongly argued against this interpretation
was the light variation the object exhibited, which resembled those of
rotating artificial satellite trails seen in wide field astronomic al
photographs. The second factor is that the object's pre-encounter orbit
of 1991 would have made it unstable in close approaches to the Earth on
a time scale measured in millennia. This means, that if it is an
asteroid, it would have recently arrived in that orbit, which is, Steel
states, very unlikely.
Therefore, concludes Steel, we have to seriously
consider the possibility that this object has "an alien genesis." Given
our meager surveillance of near-Earth objects, there is little chance
that objects of this kind would have been spotted in the past. There is
nothing here, in other words, that would contradict the alien probe
hypothesis, says Steel.
Steel's probability analysis does not end here.
He goes on to tackle an issue that not doubt made his colleagues pale.
Was 1991 VG under control or making a random passage by the Earth, he
asks? Since only "about one in 50 objects passing randomly within 0.022
AU have perigee heights as low as 0.0031 AU," Steel thinks there is a
"possibility that it was a singular alien space probe on a controlled
Steel ends his surprising analysis on a cautious
note, however. His personal bias, he states, is that 1991 VG is really
a man-made artificial object. But if it was, he concludes, then it's
observation was really an incredible fluke. So much so, in fact, that
scientists, he says, should "consider the possibility of some other
origin for it."
All in all, it's quite an amazing piece of work.
But I can't help but wonder if he's being serious. After all, it does
appears in an April issue. Nobody likes to be a fool.
On the other hand, Steel is not the kind of
scientist who pulls his punches. In his new book about the threat that
asteroids and comets pose to life on Earth, he speculates that
Stonehenge was originally erected during a period of intense celestial
bombar dment--some perhaps of Tunguska-like force--about 5,000 years
ago. Stonehenge's purpose, he ventures, was "to monitor meteor rates in
order to predict when storms were due." Steel doesn't expect this
hypothesis to be warmly welcomed by anthropologists and antiquarians.
Nor will SETI astronomers take kindly to the notion that an alien probe
may have performed a reconnaissance mission of Earth in 1991. Of
course, human-built space probes have done just that in our solar
system for the past quarter century. Why couldn't someone out there be
taking a peek at us?