ASTR 1210 (O'Connell) Study Guide 18
Because it fixes the ultimate scope of the human universe by exploring
the largest scales of space and time, astronomy has always had
a strong hold on the imagination. Inevitably, discoveries about
stars and planets raise questions about life on other worlds.
Speculation about inhabitants of other planets goes almost as
far back in history as there are written records, but it was given new
impetus after 1550 by the enormous Copernican/Galilean universe, which was
potentially infinite in extent and possibly filled with planets
like the Earth. This idea was enthusiastically embraced by
early post-Copernican writers like
Giordano Bruno and Thomas Digges.
Until the end of the 19th century, aliens were usually imagined to be
enlightened and benevolent creatures. Since then, the popular concept
of aliens has darkened considerably. As the movie poster above
vividly testifies, they are now typically viewed as menacing (the
Steven Spielberg cutie-pie creations in "ET" and "CE3K"
The change can be traced to a single novel, stimulated in turn by
astronomers' studies of the planet Mars. This lecture discusses the
novel and one of its main legacies: a remarkably widespread form of
mild mass hysteria, the "UFO" phenomenon.
Martians rule the British Navy in "War of the Worlds"
A. The War of the Worlds
Claims of some astronomers (1875+) to have detected
Martian "canals" and
Percival Lowell's widely
circulated arguments that these were artificial and were built by
civilizations on Mars provoked intense public interest in
Intrigued by the notion of life on Mars, H.G.
Wells wrote The War of the Worlds (1898)
- This was the first hostile alien invasion story. It struck a
tremendous resonance in the popular imagination and became the archetype for
a vast body of later science fiction & other speculative literature.
- Translations to the panic-inducing
1938 Halloween eve radio broadcast (by Orson Welles, no relation)
and the first special-effects-heavy
invasion film (1953) heralded a major
wave of media
invasion stories (ca. 1940 to present).
- Wells was one of the first writers to understand clearly the wider
implications of scientific discoveries.
- In WoW, he combines the vast Copernican cosmos (no longer
centered on the Earth or mankind's welfare) with Darwinian
evolution, which implies competition for scarce resources and
"survival of the fittest."
- The inevitable implication of these two ideas is
interplanetary migration, a concept Wells first
introduced in his novel. The evolutionary imperative means that
migration can take the form of a hostile invasion. (Recall that the
Mars envisioned by Lowell was a desert planet, where the inhabitants
were in a desperate struggle for survival.)
- More generally, Wells recognizes that the extraterrestrial
environment is not benign for humans:
"We can never anticipate
the unseen good or evil that may come upon us suddenly out of
Modern astronomers would certainly agree with that statement. Public
fascination with aliens notwithstanding, the modern assessment is that
realistic threats from advanced alien lifeforms are a much more remote
possibility than those from our natural cosmic environment
(asteroid and comet impacts, solar activity, supernovae and other
stellar explosions, etc.).
- Wells also incorporated ecological ideas in the form of the
symbiotic relationship between advanced lifeforms and microorganisms
and the fact that this will differ from planet to planet. The humans
are powerless in the face of Martian military technology, but [spoiler
alert] terrestrial bacteria prove fatal to the Martians and save
mankind in the end.
- Wells was a social commentator, not a scientist, and the novel
constitutes an incisive critique of modern life: the evils of
colonialism, now visited ruthlessly upon the world's largest colonial
empire by the Martians; the
fragility of civilization (e.g. the food chain is inverted in a
matter of hours, and humans become Martian dinners); the shallowness
of modern religion and conventional moral judgements (e.g. the
- Wells recognized (and implicitly warned about) the rapid pace of
(human) technological development and its implications for society
- The military technology of Wells' Martians is utterly
overwhelming yet is not even 100 years more advanced than their
human opponents'. The US military today could easily handle the
Martians in the story. (But compare this measly one century Martian advantage
to the millions of years of development that are likely to separate us
from any real space-faring aliens.)
- Wells was adept at seeing where technology was leading. His
fighting machines (tanks) and poison gas materialized as key
weaponry in World War I, 15 years later. In later works, Wells
discussed the military importance of aircraft and atomic weapons well
before their actual use.
- The larger implication is that technology is rapidly transforming
human cultures, and the consequences are not easy to predict.
- Wells was not optimistic that mankind would take the lessons in his
writings to heart. His self-epitaph: "I told you so. You
| Intrepid junior
scientist David notices
something's wrong in the backyard in this comic-book promo for the film "Invaders from Mars,"
a classic 1950's paranoid fantasy in which his parents and most other
adults are taken over by the invaders, except for a dashing astronomer
and a beautiful doctor, who help David save the world---or do they?
One lasting legacy of Lowell, Wells, and a vast amount of speculation
by others is the "UFO" controversy. What started as a legitimate (if
mistaken) interpretation of astronomical observations and a brilliant
piece of fiction has become a worldwide mini-industry, with a
multitude of committed believers and its own media and interest
groups, not to mention millions of web sites. It is based on the
belief that the Earth is under continuous surveillance by alien
spacecraft and that there is a government conspiracy to
cover this up.
"UFO" is an abbreviation for "Unidentified Flying Object", meaning
something unfamiliar in the sky, possibly artificial.
- Supermarket tabloid view: UFO's are always alien
- Scientific view: just as the description itself implies, in most
cases the "object" is not identified, whether as a spacecraft
or an entirely normal (natural or human) phenomenon.
UFO's are an example of an anomalistic phenomenon: something
apparently inconsistent with the prevailing scientific consensus but only
Where do anomalistic phenomena fit into the scientific context?
Our scientific understanding of many aspects of the natural world is
truly profound, as it should be after hundreds of years of concentrated
effort. It encompasses almost everything we encounter in everyday
If our fundamental assumptions about the physical or biological world
were seriously flawed, then, as discussed
in Study Guide 9, much of the technology
we depend on in everyday life would simply not work. For
instance, our deep understanding of electromagnetism is tested
millions of times each second in every electronic device on Earth.
Nonetheless, at any time, there are many well-documented
phenomena that scientists do not adequately understand.
These unsolved problems are what drive scientific curiosity and
what active scientists work to explain.
- Examples from the past: stars; motions of the planets; the "red
spot" on Jupiter; the Bubonic Plague; human genetics.
- Examples from the present: "dark" matter and energy;
junk DNA; Alzheimer's disease.
Young scientists, especially, like to work on such problems. There
are strong incentives for scientists to discover new phenomena or
interpretations that countervail the accepted wisdom. That is how
young people make careers in science. However, they always have the
obligation to demonstrate, usually by very hard work, the validity of
new views to a (properly) skeptical audience.
The first steps in scientific understanding are to identify a
phenomenon and to carefully establish its properties. Interpretation
cannot begin until it can be placed in the rich context of what we
In contrast to the subjects of mainstream science, "anomalistic"
phenomena are not even established as real. There is
insufficient objective, controlled evidence to show that the
claimed phenomena even exist, let alone imply something beyond the
capacity of normal science to explain. There is much more wishful
thinking than hard thinking about such topics.
Most of the subjects of "pseudo-science"
fall in this anomalistic category: ESP, telekinesis, ghosts, astrology,
psychic forecasts, much "alternative" medicine, etc.
Nonetheless, you will find more books on pseudoscience in a typical
bookstore than on science itself. They sell well because of their
emotional appeal and because most people do not know how difficult it
can be to validate scientific ideas or how to apply suspended judgement
(skepticism, see Study Guide 1)
to new propositions.
A long history of "strange things" in the sky
Apart from the familiar, well-verified phenomena in the sky,
many of which we have already discussed, there have always been reports
of unusual, transient features:
The modern era of "UFO's" began in June 1947 with widespread media
coverage of a report that civilian pilot Kenneth Arnold had seen a formation of "saucer-like" craft flying
at speeds over 1000 mph near Mt. Rainier.
- Records of these extend back as far as 400 BC. They include
unusual lights or color displays, sounds, moving objects, and (in the
19th century) airships. Almost none were subjected to critical
scientific analysis until after 1900.
Most of these undoubtedly originated from real phenomena which we
now understand well, like light scattering in the atmosphere,
comets, and meteoroids, which were
misperceived as supernatural or anomalous events.
- Publicity over Arnold's sighting led to an intense "flap" of
"flying saucer" reports over the next several years (including the now-infamous Roswell, NM case,
although this was a low-profile incident at the time).
A telling irony is that almost all of these reports involved
flying disks or saucers even though Arnold's original description was
that the strange objects looked like swept-wing aircraft (see this sketch) and were like saucers
only in that they "flew erratic, like a saucer if you skip it across
the water." Newspaper accounts of the Arnold incident compressed
the description into "saucer-like objects," so the public assumed the
craft were round. The erroneous media description clearly strongly
shaped the subsequent reports.
Interest in the Arnold report was amplified by building cold-war
tensions with the USSR. In fact, the primary concern of the government
at the time was that the "saucers" might have been experimental
- 1947-today: Thousands of reports of strange flying objects, often
in similarly concentrated flaps, triggering USAF & other government
investigations (none of which lend credence to the extraterrestrial
hypothesis). Since the 1970's, there have also been many reports of
(temporary) human abductions by aliens.
"Extraordinary claims demand extraordinary evidence."
Empirical validation is essential---but using only the highest
standards. Because of its importance, if true, the extraterrestrial
hypothesis requires unimpeachable evidence. We must eliminate all
ordinary explanations before we appeal to extraordinary ones.
However, the UFO phenomenon has never been able to meet the
conventional standards for scientific validation, let alone the higher
ones needed to accept an extraterrestrial interpretation.
- The data are marginal:
- "Eyewitness" accounts are often faulty, especially from untrained observers.
- Reams of courtroom records in routine criminal cases vividly
attest that eyewitness testimony is often greatly inferior to
circumstantial evidence. See
"On Being Certain" by R. Burton.
- It is hard to judge visually the distance,
speed, & motion of objects in the sky---even for experienced observers
like airline pilots. Since inferred speed depends on inferred distance,
claims of large velocities are often doubtful.
transient phenomenon is hard to assess well.
- For these reasons, objective evidence is preferred, based
on, e.g. radar or imaging.
- But there has been precious little high quality, objective
evidence concerning UFO's in the last 60 years.
- "Have you noticed since everyone has a camcorder these days no
one talks about seeing UFO's anymore?" Car Talk, Sept 2002.
Yes, it isn't helpful to the alien enthusiasts that even though there
are now hundreds of millions of capable video cameras (e.g. in cell
phones) spread across the face of the Earth, there are no better video
recordings of alien spacecraft than there were 40 years ago. This is
despite the proven ability of people to capture sudden, unusual, brief
events (airplane crashes, for instance). The alien pilots are a lot
more bashful than the Los Angeles Police Department.
- A sighting of an "unidentified" object in the sky doesn't demonstrate
the existence of an anomalistic phenomenon. It simply creates
a list of possibilities for its explanation.
- That list must include the full range of possible
scientific explanations (including a mistake or wishful thinking).
The list must be refined using our full cumulative understanding of
- Something that looks strange to an untrained observer may have
a perfectly ordinary explanation. Even if not, that doesn't mean
the explanation is beyond conventional science.
- Even the word "flying" is prejudicial in a "UFO" report. What are
often called UFO's aren't flying at all. They are in the sky, but
they may be outside the Earth's atmosphere: stars, planets,
Scientific assessment of UFO reports
The 5-10% of reports without obvious explanations mostly have
insufficient information for analysis. However, a number of more
complete cases have been pursued carefully and have turned up no
convincing evidence of extraterrestrial craft. (E.g. see the Philip
Klass book UFO's Explained, cited below.)
Some famous cases were deliberate frauds/hoaxes. There are many
more cases of obvious self-delusion or irresponsible hype.
The Roswell incident is an egregious
example of the latter, in which a few fragments of a crashed,
classified US high-altitude balloon intended to survey for
sonic evidence of Soviet nuclear tests were claimed to be irrefutable
evidence of an alien spacecraft.
- There have been many UFO reports, but hundreds of badly
documented cases are less useful than a single, thoroughly documented
Only a minority involve photographs. We will show a number of UFO
photos in class and consider the possible explanations of them.
- 90-95% of UFO reports are clearly misperceived natural or human
phenomena: airplanes, balloons, planets, stars, clouds,
unusual atmospheric phenomena (e.g.
- The most commonly reported "UFO" other than airplanes is
Venus. It can be dazzlingly white and astonishingly bright,
making people think it's close by, when in reality it is millions of miles
away. "Seeing" effects in
Earth's atmosphere can cause it (and other planets and bright stars)
to appear to pulsate, wobble, or change color.
Here's a zeroth-order reality
check if you see something strange in the sky:
- Watch for 5 minutes. Is the "UFO" stationary with
respect to the stars?
If yes, then it's probably a celestial object, a minimum of many millions
of miles from Earth.
- Is it within about
40o of the western or eastern horizon?
- Is it in a Zodiacal constellation?
If yes to all three, then it's probably Venus.
Jupiter is also a commonly-reported "UFO," but it need
not meet criterion (2) here.
Often, there is a willing suspension of critical
faculties by UFO promoters: after all, the UFO industry is comfortably
Historical UFO reports are clearly strongly colored by people's
prejudices. In the 19th century, reports tended to be of
"airships"---i.e. balloons or dirigibles. Where are the "saucer"
reports before 1947?
There is an overwhelming media influence, especially from
film or TV dramas (e.g. above right), on the frequency and especially
on the similarity of modern reports.
Ironically, the similarity is then cited as evidence for the reality
of the phenomenon.
Saucer-like craft had themselves debuted in 1920's science fiction
magazines----20 years before people started reporting them in the
Public impressions of alien spacecraft and aliens themselves are now so
strongly driven by fictional media presentations, that it is almost
impossible to disentangle reality from prejudice in most reported
Many psychological factors are involved (e.g. Cold War tensions
and widespread fear of a Soviet attack coincided with early flurries
of UFO reports). Overall, the UFO phenomenon shows symptoms of a mild
form of mass
hysteria (a well documented affliction, the more extreme
episodes of which are described at the link just given and in the book
Belief in UFO's can have religious overtones (e.g. the
ET's substitute for the second coming of Christ) and has sometimes
been linked to explicitly religious activities:
Finally, what about the credibility of an almost impenetrable
government conspiracy to cover up evidence of alien visitations for
the last 60 years?
Answer that for yourself with three letters: I.N.S.:
The bottom line is that in 60 years, there has not been a single
UFO case meeting the basic standards of evidence that are applied
to mainstream scientific investigations.
The last decade has featured an embarrassingly rich tableau of
ineptitude and porosity by government agencies. Lest we forget one of
the classic cases: the Immigration and Naturalization Service issued
welcoming visas to some of the September 11th hijackers 9 months after
they had died in the wreckage of their aircraft.
- UFO's present a very low probability of being a new/important natural phenomenon.
- There is a near-zero probability of alien spacecraft being involved.
- That is the scientific assessment today. Of course, the evidence
could improve dramatically tomorrow. The scientific
consensus has sometimes rejected the right ideas for the wrong reasons
(e.g. meteorites, continental drift).
- But wait for the evidence.
Reading for this lecture:
H. G. Wells War of the Worlds (an electronic version from
Project Gutenberg is
Study Guide 18
Optional reading: Philip J. Klass UFO's Explained (Clemons
Library, TL 789.K56 1975)
Optional reading: Curtis Peebles Watch the Skies! A Chronicle of the
Flying Saucer Myth (Clemons Library TL789.3 .P44 1994).
Reading for next lecture:
Study Guide 19
Bennett textbook, Chapter 10.
in Pop Literature
War of the
Radio Broadcast of "The War
of the Worlds" (Orson Welles, 1938)
War of the Worlds, The Musical(!)
The Dr. Zeus collection of
"War of the Worlds" book covers. Trace the evolving
visualizations of one of the most re-published novels in history.
Electronic versions of other H. G. Wells stories
Summer 2005 Steven Spielberg-Tom Cruise blockbuster film version of WoW (Wikipedia)
of Invaders From Mars (1953 film)
Life in the Universe (Study Guide 23)
Extraordinary Popular Delusions and the Madness of
Crowds Charles Mackay (1841).
Famous compendium of cases of mass hysteria, collective
delusions, economic mania, and magnificent scams. You will
immediately realize that some of these are amazingly similar to the
dot-com and toxic mortgage bubbles. Human frailties have not
diminished much in the last 2000 years, and this book provides
vivid documentation. Required reading for anyone planning a
career in social science, politics, law, marketing, or
As of 2014, you can find upwards of 200 million pages(!)
on the Web that discuss UFO's (up by 50x in 10 years). The vast
majority of these will feature uncritical acceptance of the ET
hypothesis. Some antidotes:
June 2014 by rwo
Artwork here is from
War of the Worlds, The Musical and original film posters & promo
material. Scan of the cover of the 1993 edition of WoW from
Text copyright © 1998-2014 Robert W. O'Connell. All
rights reserved. These notes are intended for the private,
noncommercial use of students enrolled in Astronomy 1210 at the
University of Virginia.