Todays Overview

1
Todays Overview

• Writing Assignment Update
• The Drake Equation (LIU Ch 11)
• SETI (LIU Ch 11)
• The Fermi Paradox (LIU Ch 13)
• Video Kidnapped by UFOs?, The True Story of
  Alien Abductions
• Assignments for next week
• Short quiz on the previous lecture (Life in our
  Solar System and Extrasolar Planet Detection) and
  this lecture
• Please take 1 page to describe your impressions
  of the video we watch today.
• Read an online excerpt from the Lewis Clark
  Journal (3/23-4/27/1805.
• http//www.pbs.org/lewisandclark/archive/idx_jou.
  html

2
Writing Assignment

• Today the mission destination tables were due,
  but there is an extension until Friday (5/28) at
  5pm. Please email me your table by then.
• Your paper will be due during class in the final
  week of classes, although you may turn it in
  earlier if you like. Your paper should be 3-5
  typed pages.
• Remember that during the final class, you will be
  doing a 5 minute presentation that summarizes
  your mission.

3
Gendenkan experiments

• Do you think we are currently being visited by
  alien spaceships on a regular basis?
• Do you think primitive life exists elsewhere in
  the Universe?
• Do you think other advanced civilizations exist
  somewhere else in the Universe?
• Do you think humans will colonize other Solar
  Systems?

4
SETI

• The Search for Extraterrestrial Intelligence
• According to Merriam Webster, intelligence is the
  ability to learn or understand or to deal with
  new or trying situations
• SETI defines intelligence as a civilization from
  which we could potentially receive a signal (ie.
  radio).
• Nb The first use of radio on Earth occurred in
  the early 1890s. High frequency radios (ones
  that can penetrate the Earths ionsphere) werent
  developed until after WWII. Should we expect to
  receive signals from other civilizations?

5
Fundamental Question

• Are we alone out here in the Universe?
• Ie. Are we special?
• The Weak Anthropic Principle if the laws of
  nature had been slightly different, then humans
  would not have transpired.
• The Strong Anthropic Principle the laws of
  nature were established so that humans could
  prosper.

6
The Great Demotions

• In the 17th century, humans had thought that
  Earth was the only world. Galileo proved this
  wrong by revealing that the Moon certainly does
  not possess a smooth and polished surface and
  that other worlds might look just like the face
  of the Earth itself. Wrong!
• The Earth is at the center of the Universe.
  Wrong!
• The Sun is at the center of the Universe. Wrong!
• Our Milky Way is the only galaxy. Wrong!
• Our galaxy is at the center of the Universe
  (center of the expansion of the Universe). We
  have a unique vantage point on space. Wrong!
• No other star has planets. Wrong!
• If our position in space doesnt reveal our
  special role, our position in time does Weve
  been in the Universe since The Beginning (give or
  take a few days). Weve been given special
  responsibilities by the Creator. The Earth is
  6,000 yrs old. Wrong!
• There is something special about our motion here
  on the Earth. Newton called this a privileged
  frame of reference. Albert Einstein later
  postulated that all inertial frames of
  reference hold the same physical standards.
  This is his Special Theory of Relativity. Wrong!
• Well, even if our position, our epoch, or motion,
  and our world are not unique, maybe we are.
  Were different from the other animals. Were
  specially created. The particular devotion of
  the Creator of the Universe is evident in us.
  Then Charles Darwin demonstrated the power of
  evolution, and that we are descendants of
  animals. Wrong!
• Even if were closely related to some of the
  other animals, were different not just in
  degree, but in kind on what really matters
  reasoning, self-consciousness, tool making,
  ethics, altruism, religion, language, nobility of
  character. Wrong!
• Maybe were humiliatingly related to apes, but at
  least were the best there is. God and angels
  aside, were the only intelligent beings in the
  Universe. Wrong?

Information from Pale Blue Dot by Carl Sagan
7
The Drake Equation
x flife
x fciv

• This is a variation of the Drake equation first
  expressed in 1961 by Cornell University
  astronomer Frank Drake. Dr. Drake is known as
  the father of SETI, and has been a pioneer in the
  field since its inception.
• He and others were optimistic about the fractions
  and they used this to begin SETI.

8
What we think we know

• Nstars200,000,000,000
• fhp?
• Fraction of stars with planets 0.1-1.0

Planets found to date are most common around
metal rich stars. But still 10 of stars
surveyed for Jovians are known to have at least
1. And the surveys are just now reaching far
enough out to detect our own Jupiter if it were
around another star. Some believe fplanet1.
9
Which Stars make Good Suns?

• They must be old enough so that life could arise
  (Billion years)
• this rules out the massive O B main sequence
  stars
• They must allow for stable planetary orbits
• this rules out binary and multiple star systems
  (about half)
• They must have relatively large habitable zones
• region where large
• terrestrial planets
• could have a surface
• temperature that
• allows water to exist
• as a liquid

10
Habitable Planets

• fplanet 0.1 to 1.0
• But fhp0.01 to 0.1 (1/10th of fplanet)
• Long enough life 1 Billion years
• Large enough Habitable zone
• Why dont we know the exact value?

11
Detection Problem

• Earth is 1010 times fainter than the sun at
  optical wavelengths
• 106 times fainter
• at 10 microns
• At 10 pc, habitable
• zone is only 0.2
• (Earths orbit appears as a dime at 6 miles)
• (Earths diameter would be a dime at 150,000
  miles)

12
Future observatories

• Kepler
• Planetary transits
• Terrestrial Planet Finder
• Interferometry mission to image Earth-like
  planets
• fhp in the Solar Neighborhood will be coming soon!

13
Flife?

• So what is the fraction of habitable planets
  where life actually forms?
• Again, life seems ready to start given the right
  environment. This seems to hold for the Earth,
  atleast.
• What do we know about the other planets in the
  Solar System?

ppts\mforce.wav
14
Our Best Candidate for Extraterrestrial Life

• Mars is the best candidate to host life for
  several reasons
• Mars was apparently warm wet for some periods
  in its distant past
• It had the chemical ingredients for life
• It still has significant amounts of water ice
• Pockets of underground liquid water might exist
  if there is still volcanic heat
• Mars exploration focuses on finding evidence of
  water, biological activity and ultimately fossils.

Mars at 2001 opposition Hubble Space Telescope
image
15
Fossils on Mars?

• If we never find fossils on Mars, then flife is
  probably small.
• If we ever find fossils on Mars, then flife is
  probably 1.0.
• Again, stay tuned

16
On what fraction of living worlds do
civilizations develop? fciv

• Again, we have only 1 example (1 for 1, or 1 in a
  billion)?
• Certainly fciv is not 1.0 since some planets are
  doomed to be destroyed by parent star or large
  meteor collisions, but it could be a large
  fraction.
• Mayr is not optimistic. He points out that only
  one branch of bacteria has ever made it to
  multicellular status.
• Perhaps all complex life evolved from a single
  lucky bacteria.
• Lets assume fciv is only 0.01 (1 in a 100 living
  worlds develop a civilization).

17
Civilizations out there now? fnow

• Carl Sagan and others pointed out that technical
  civilizations may be short lived.
• Most of Suns history we havent been here and at
  most well be here for about 20 of the Suns
  life.
• That is we might destroy ourselves (and maybe all
  advanced life)
• Nuclear War
• Biological warfare
• Run out of resources (overpopulation)
• Run away greenhouse
• Or we are destroyed
• Parent star dies
• Nearby supernova
• Major asteroid impact
• If lifespan is 100 years, then fnow0.00000001
• Lets assume fnow0.001 (10 million year life)

18
Putting it togetherNumber of Civilizations in
the Galaxy right now

• Nciv Nstarsx fhpx flife x fciv x fnow
• Nstars 200,000,000,000
• fhp0.01 to 0.1
• flife0.1 to 1.0
• fciv0.01
• fnow0.001
• Ftotal 1 in 100,000,000 to 1 in a million.
• Nciv2,000 to 200,000 today
• But there have been 2,000,000 to 200,000,000
  civilizations before.
• Can we find each other?

19
Practical Example of the Drake Equation

• How many piano tuners are in LA?
• What are the relevant numbers?
• Can we accurately estimate this number?

20
So how many piano tuners are in LA?

• How many people live in LA? 9,000,000
• On average, how many people are there in a LA
  household? 3
• How many households get their pianos tuned
  regularly? 1/100
• How many times per year does a household get
  their piano tuned? 1/2
• How long does it take a piano tuner to tune a
  piano, including travel time? 4 hrs.
• How many hours does the average piano tuner work
  a day? 8 hrs. How many days a week? 5 How many
  weeks in the year? 50
• Calculations
• 9,000,000 people 1 household/3 people
  3,000,000 households
• 3,000,000 households 1 tunes regularly/100
  households 300,000 households tune regularly
• 300,000 households tune regularly1/2 tune each
  year 150,000 pianos tuned in 1 year
• 1 piano tuner can tune 2000 hours/year1/4hours50
  0 pianos/year
• This means that we calculate there should be 30
  piano tuners who work full time in Los Angeles.
  According to the Yahoo! yellow pages, there are
  43 piano tuning services in Los Angeles County.
  Even without doing any statistical studies, we
  were within a factor of 2 within the real value!

21
What types of civilizations are possible?

• Planetary civilizations (Type I) they use the
  resources of their home planet.
• Stellar civilizations (Type II) they use many
  of the resources from their host star. This
  includes reworking their own Solar System.
• Galactic (Type III) civilizations they use the
  resources of their entire galaxy.
• Dyson Spheres idea that a civilization would
  build a sphere around a star, which would collect
  and utilize the most energy possible. The sphere
  would emit radiation in the infrared.

M.C. Escher's Concentric Rinds
22
Can we find these other civilizations?

• SETI has been searching for intelligent life over
  the past 40 years.
• Frank Drake started Project Ozuma where he
  searched for artificial radio emission from a
  number of nearby Sun-like stars.
• For a short amount of time NASA was involved in
  SETI, but then it withdrew its funding. Now SETI
  investigations are carried out by the SETI
  Institute and UC Berkeley.

23
What types of signals are there?

• Signals used for local communications.
• With our technology, we could only detect these
  signals from a civilization less than 1 lyr from
  us.
• Signals used between a civilizations home planet
  and a nearby colony or some other spacecraft.
• With our technology, we could only detect these
  signals from a civilization within a few lyrs.
• Intentional beacons that broadcast to anyone who
  may be listening.
• With our technology, we could only detect these
  signals from a civilization out to a few tens of
  lyrs.

24
Search for ExtraTerrestrial Intelligence

• Maybe travel is much harder than we think. What
  about communication instead of spaceships?
• That is the idea behind the SETI program.

• Use radio telescopes to listen for encoded radio
  signals.
• search strategies are used to decide which stars
  to observe
• now they scan millions of frequencies at once
• Due to low chance of success and large amount of
  time required, SETI is now privately funded.

25
SETI
Arecibo radio observatory

• Radio SETI
• Project Phoenix (largest program to date) ended
  March 5, 2004.
• Searched all 710 star systems within 150
  light-years of Earth. They searched 70 million
  radio channels simultaneously. Nothing!
• Does imply there are not large numbers of
  civilizations transmitting at many frequencies
  Frank Drake (2004)
• Other programs SERENDIP, META (Megachannel
  ExtraTerrestrial Assay), BETA (Billion-channel
  Extraterrestrial Assay) have tried other
  strategies Nothing!
• Problem theres a lot of radio background these
  days. Its difficult to distinguish a true
  alien signal.
• Optical SETI
• Optical signals are a less efficient means of
  transmission for civilizations, but this still
  seems like a viable means of communication. The
  Allen Telescope Array will be fully operational
  this year (?), and it will be maintained by SETI
  and UC Berkeley.
• There are some unresolved events, but all have
  lacked reproducibility. Weve never been able to
  find any of them again.

Allen Telescope Array Element Prototype
26
Sending our own beacon

• In 1974, we sent out our own beacon to the stars.
  Specifically we sent notice of ourselves to M13,
  which is a globular cluster that has a few
  hundred thousand stars.
• M13 is 21,000 lyrs away, so a return signal
  wouldnt be received for atleast 42,000 yrs!
• Many people in the public argue that we should
  not be so quick to send out information about
  ourselves. They think we should just sit back
  and listen first!

This is the signal sent to M13. From left to
right are numbers from one to ten, atoms
including hydrogen and carbon, some interesting
molecules, DNA, a human with description, basics
of our Solar System, and basics of the sending
telescope.
27
Where are the Aliens?

• Assuming, like us, most civilizations take 5
  billion yrs to arise.
• the Galaxy is 10 billion yrs old, 5 billion yrs
  older than Earth
• IF there are other civilizations, the first could
  have arisen as early as 5 billion yrs ago
• there should be many civilizations which are
  millions or billions of years ahead of us
• they have had plenty of time to colonize the
  Galaxy
• Will we colonize the galaxy? With modest
  improvements in technology it is plausible that
• within a few millennia, out of curiosity or
  boredom, we could colonize a few nearby stars
• in 100,000 years, our descendants could spread
  out to 100s of light years
• in a few tens of millions of years, we could have
  outposts throughout the Galaxy

28
Where are the Aliens?

• Sowhere is everybody? Why havent they visited
  us?
• this is known as Fermis paradox
• named after physicist Enrico Fermi, who first
  asked the question in 1950
• Fermi also produced first controlled nuclear
  reaction.
• Stronger version Time to evolve civilization is
  longer than the time to colonize the galaxy. So
  it should be winner takes all!

29
Maybe civilizations are too far away, or they
dont know about us?

• TPF will only work to 10 pc, and it might take us
  a long time to reach 100 pc.
• Also, our tv signals only reach 10s of pc.
• 100 pc sphere has a volume of 4.1x106 pc3.
• Includes only 1.7 million stars.
• So from our fractions, thats from 0.02 to 2
  civilizations.
• Maybe were just not looking far enough?

30
But TPF Turned Around

• Ben Zuckerman (UCLA) has used the possibility of
  TPF to argue against intelligent life.
• If we can search for life bearing planets nearby,
  why couldnt aliens find us?
• He points out that the Solar System is moving
  relative to other stars so our neighbors are
  constantly changing.

31
Solar Motion

• The Sun and other stars are moving at about 220
  km/sec around the Galaxy.
• But we arent moving identically. Typical stars
  move 10 or 20 km/sec faster or slower than this
  average rate.
• Sun moves 16.5 km/sec
• compared to local average.
• This means our nearest neighbors are constantly
  changing.
• 400,000,000 stars have passed by since the
  atmosphere became oxygenic!
• Each was that close for an average of 6 million
  years.
• But no one appears to have
  stopped by.

32
Or did they?

• Could we be aliens?
• Fossil record shows a direct link from extremely
  primitive life to us.

• Some have suggested that the early Earth was
  seeded with primitive life.
• But why not just send intelligent colonists or
  robots?
• To date, there are no artifacts on the Moon, Mars
  or the Earth of any previous intelligence.
• Most of Mars and the moon have now been mapped to
  roughly boulder sized objects. Little if any
  erosion on the moon during the past 4 Billion
  years.

33
Possible Solutions to Fermis Paradox

• We are alone.
• One or more of our fractions is way too
  optimistic.
• Earths are rarer than we think.
• Moon needed to stabilize rotation. Otherwise our
  axis would often tip over creating climate
  extremes.
• Jupiter needed to sweep inner solar system of
  debris. Otherwise bombardments would cause 100
  times more mass extinctions.
• Terrestrial planets are much rarer than Jovians.
  We were an accident during the formation of the
  sun.
• Life almost never becomes complex.
• Lucky bacteria theory
• Civilizations are extremely rare and we are the
  first one to arise
• Then we are unique, the first components of the
  Universe to attain self-awareness.

34
Possible Solutions to Fermis Paradox

• Civilizations are common, but no one has
  colonized the Galaxy.
• Perhaps interstellar travel is even harder or
  costlier than we imagine
• But every civilization must have resisted the
  urge.
• Perhaps most civilizations have no desire to
  travel or colonize
• Perhaps most civilizations have destroyed
  themselves before they could explore
• Will we explore the stars, will we happen to
  destroy ourselves first?
• There is a Galactic civilization.
• It has deliberately concealed itself from us
• Are we the Galaxys rookies, who may be on the
  verge of a great adventure? This implies the
  aliens are obeying the prime directive by not
  disturbing the us.

35
More questions than answers.

• Life and even intelligent life may (or may not)
  be a natural and common result of the
  evolutionary processes of the universe.
• Life may (or may not) be common.
• We may (or may not) colonize the galaxy.
• Alien intelligence may (or may not) know were
  here.
• We may (or may not) evolve into completely new
  forms.

36
UFOs Are aliens among us?

• Appearance
• Jet planes first introduced at the end of World
  War II ? public aware of fast-moving aircrafts
• First UFO claim in June 1947
• Flew erratic, like a saucer ? flying saucer
• 50 of the public believe in the existence of
  UFOs

• Project Blue Book US Air Force Investigation
• 20-year active investigation
• 90 of claims discarded
• Remaining 10 indeterminate
• Lack of proof is no proof

37
Crashed Aliens in Roswell, NM
An alien spaceship?

• Known facts
• Rancher found crash remnants July 1947
• Military personnel picked up the debris
• Remains shown next day in Fort Worth, TX
• Claimed to be remains of a weather balloon
• Claims by Stanton Friedman (1978)
• Crash an alien spacecraft
• Alien bodies also recovered
• Story hushed up by military
• Analysis
• Project Mogul balloon used for secret monitoring
  of Soviet tests
• Witness accounts in seventies contradicted or
  discounted
• Motive for secrecy not clear
• Ability to keep secret highly doubtful

38
Area 51

• Aka. Groom Lake
• A secret military facility about 90 miles north
  of Las Vegas. A 6 x 10 mile plot of land, which
  consists of a dry lake bed used for landing jets.
• Originally, the site was used to test
  experimental jets and other aircraft.
• Nowadays, Area 51 is notoriously associated with
  US government UFO conspiracy theories.
• If you cross the Area 51 border, you get arrested
  and a 600 fine.

39
Crop Circles, Abductions, etc.

• Crop circles
• Claim too accurate and too quick to be done by
  humans
• Shown to be possible, and there have been
  organized competitions in crop circle making
• Some are admitted to be pranks
• Abductions
• Sleep paralysis common dream during rapid eye
  movement (REM)
• Also known during day dreaming

40
Ancient Visitations

• Ancient drawings
• Claim pictures of aliens
• Counterclaim other possibilities abound
• Nazca markings
• Claim needed unavailable knowledge
• Counterclaim did not need unavailable knowledge
• Claim could only be seen from space
• Counterclaim could be form of worship
• Egyptian pyramids
• Claim Egyptians could not build the pyramids by
  themselves
• Counterclaim it was shown that the pyramids
  could be constructed with tools available then

41
Cover-Up Scientific Disinterest

• Cover-up
• Motive to avoid alarm 50 already think that
  aliens have landed
• U.S. Government is notoriously unable to keep
  secrets known by many for a long time.
• All other governments need to participate in the
  conspiracy, unless the aliens just chose to
  negotiate with the US.
• Scientific disinterest
• Stems from lack of evidence, not disinterest.
• If there was serious evidence, or the chance to
  obtain serious evidence, scientists would jump at
  it.