Extra-terrestrial visitors

1
Extra-terrestrial visitors

• Have they visited are they here now?
• Are we that special?

2
Evidence

• Extra-ordinary claims require extra-ordinary
  evidence.
• Do we see aliens in the street?
• Do we have any (verified) alien artifacts?
• Do we have photographs or spectroscopic evidence
  of alien spacecraft?
• UFOs unidentified flying objects

3

• We are scanning the skies with a huge array of
  instruments yet this type of photograph is yet
  to be seen.

4
UFO reports

• Interestingly, such reports abound since 1947,
  the close of the second World War and the
  commencement of the Cold War
• Is this a coincidence? Aircraft had suddenly
  become common as had air transportation for
  people.
• How accurate are the claims? Essential to be
  skeptical.

5
UFOs become IFOs

• By definition, something is unidentified until it
  becomes identified.
• The process requires a collection of information
  and an evaluation of the known facts as
  assembled.
• Regardless of what you might like the outcome to
  determine, an objective evaluation is needed.

6
The Scientific Method

• Make an observation
• Devise a hypothesis that accounts for the
  observation
• Test the hypothesis (usually with an experiment)
• Evaluate the test results and decide if they
  support the hypothesis.
• If necessary, modify or reject the hypothesis.

7
The Small Angle Formula

• D linear size of object
• a angular size of object (in arcsec)
• d distance to the object

8
Consider

• Look at the Moon how big is it? how far away
  is it?

9
Answer

• The Moon has a real diameter of 3,476 km
• The Moon is (on average) 384,400 km from the
  Earth
• At this distance, the Moon subtends an angle of
  about 0.5 degrees (equivalent to 30 minutes of
  arc or 1800 seconds of arc).
• Note that the Moon is about 100 times further
  away than it is wide.

10
A UFO?

• A 1 meter diameter grey coloured balloon at a
  distance of 100 metres would appear to be exactly
  the same size as the Moon!

11
How fast is it moving?

• To determine a speed of an object, what do you
  need to know?
• You can say how many degrees in how many minutes
  (seconds) the object moved.
• You observe a point of light move 15 degrees in 1
  minute how fast is it really traveling?

12
Answer

• If the object was 1 km away, its speed was 16 km
  per hour.
• If the object was 100 km away, its sped was 1600
  km per hour!
• So if all you saw was a light at night, was a
  person riding a bike or a distant jet plane?

13
Possible confusions

• Meteors entering the Earths atmosphere can break
  up and be very bright indeed (bolides) shedding
  material as they travel.

14
What do you see?
15
De-orbiting satellites

• Space junk abounds in orbit above the Earth
  10,000 satellites roughly.
• Bits and pieces from rockets also remain in orbit
  for small periods of time.
• Re-entry, heating to incandescence and
  disintegration (hopefully) is happening all the
  time.
• For example, Skylab and Mir space stations.

16
Venus

• By far the brightest object in our skies (apart
  from the Moon and the Sun).
• Often seen very low to the horizon and can cast
  shadows.
• Often reported to follow people around.
• Can be seen in conjunction with other planets.

17
Venus images
18
Human perception

• All too often, we see what we want to see
  believe what we want to believe.
• Opportunity also plays a role if you are
  outside more often, the chances of observing
  something increase.
• For the record, nearly 50 of all Canadian UFO
  sightings happen in BC clearer skies, warmer
  temperatures (and best marijuana growing!)

19
Percival Lowell and Mars

• Despite logic, Lowell assumed markings on Mars
  were canals forming an irrigation system on the
  planet surface.

20
The Face on Mars

• From Viking in 1976 until Mars Global Surveyor in
  2001, the face has changed!

21
The modern UFO era

• June 24, 1947, pilot Kennith Arnold reports an
  observation near Mt Rainier, Washington State.
• Arnold described the objects as moving "like a
  saucer would if you skipped it across the
  water.". 
• Bill Bequette, a reporter with the East Oregonian
  newspaper, reworked the phrase "saucer-like" and
  gave the phenomenon a name "flying saucers
• 650 reports in the continental US by July 31 1947!

22
J Allen Hynek classification scheme

• Nocturnal lights
• Daylight disks
• Radar-visual sightings
• Close encounters of the first kind
• Close encounters of the second kind
• Close encounters of the third kind

23
Countless reports

• Hynek investigated 1,000s of UFO reports.
• He noted that less unusual events correlate with
  reliable reports and that more bizarre claims
  come from less credible witnesses.
• While many observations remain unexplained (a
  VERY tiny fraction of all reports), this does not
  imply an ET explanation. Rather it suggests a
  lack of information.

24
Consensus

• As appealing as it may be to believe that UFOs
  are alien spacecraft, no solid evidence exists.
• There is the question of why would they come and
  be so secretive?
• Even assuming that a civilization was close-by
  and knew we were here, the expenditure of time
  and energy is significant why come all this way
  and scare cows?

25
Cover up? Conspiracy?

• When all else fails to convince you, reach for
  the expression Government cover up they are
  hiding the truth about aliens from us.
• Note that ALL Governments around the world are in
  unison, covering up the information UFOs are
  seen everywhere.

26
Reality check

• Government have difficulty keeping secrets
  covering up UFOs and aliens for decades seems
  highly unlikely.
• Scientists are in on it (me too?) but why?
  Further, the number of people who would now have
  to keep the secret is enormous very unlikely.

27
Erik Von Daniken

• Very popular books (and TV shows) Chariots of
  the Gods, Gold of the Gods, etc.
• Opportunistic is a word that springs to mind, not
  to mention denying the ingenuity of our
  ancestors.
• Careful scrutiny of his claims reveal amazing
  inconsistencies and hopeful exaggerations.

28
The Egyptian Pyramids

• The pyramid at Khufu at Giza took 10,000s of
  workers to complete but has been chronicled in
  history. An amazing undertaking to be sure but
  definitively human.

29
The Nazca Plains of Peru

• The various drawings on the Nazca Plains are
  associated with the Incan culture from nearly
  2,000 years ago.