the physics of ufos - university of illinois · 2-nov-12 world of science - ufos 13 polling numbers...

2-Nov-12

The Physics of UFOs

Kevin Pitts

University of Illinois

World of Science - UFOs 1

2-Nov-12 World of Science - UFOs 2

• Why UFOs?

• It all starts at Fermilab…


Phys 192: Science & Pseudoscience

• What is good science? bad science? pseudoscience?

• Topics covered

– Alternative medicine, UFOs, ghosts, cold fusion, statistics, logical fallacies, lie

detectors, climate change, creationism, …

• Last semester we performed extrasensory perception experiments, all

results negative! This semester, we‟re making videos!

Things aren’t always as they seem


A Face On Mars

Credit: The Viking Project, NASA

APOD: 1998 April 6


The Face on Mars

Credit: NASA,Viking Project,

APOD: 1995 July 22


Mars Express Close-Up of the Face on Mars

APOD: 2006 September 25

http://antwrp.gsfc.nasa.gov/apod/image/0609/face2_marsexpress_big.jpg


Polling Numbers

Gallup 1996. In your opinion, are UFO‟s something real, or

just people‟s imaginations?

Real just people‟s imagination don‟t know

48.5% 31.0% 20.6%

Gallup 1996. Do you think that UFO‟s have ever visited the

earth in some form, or not?

Yes no don‟t know

45.1% 40.0% 15.9%

In this same poll, 71% of those surveyed believe that the

government knows more about UFOs than it is telling.


Extraordinary claims require extraordinary evidence

“Dr. Pitts,

I noticed that you will be presenting a lecture entitled „The Physics of

UFOs.‟

I am not attending the lecture, but would like to know if you have written

an article on this topic and, if so, whether it is available for people to read.

On the basis of what I have read, there seems to be a fair amount of

evidence based on (a) reports from highly reliable witnesses (including

former military people, police officers, and pilots) (b) physical trace

findings, and (c) radar recordings, which support the hypothesis that at

least some reported UFOs are highly technologically advanced craft that

may have an extraterrestrial origin. The „Extraterrestrial Hypothesis‟

seems plausible for explaining at least some reported UFO sightings.

No testimony is sufficient to establish a miracle, unless

the testimony be of such a kind that its falsehood would

be more miraculous than the fact which it endeavors to

establish… -David Hume‟s maxim

“Extraordinary claims require

extraordinary evidence”

-Carl Sagan

Questions about UFOs

• Basic question

– Is there life anywhere other than Earth?

• If yes:

– Is there “intelligent” life anywhere other than Earth?

• If yes:

– Could we communicate?

– Could they come and visit us?

– Could we visit them?

– Have we communicated?

– Have we visited?


Questions/Topics

1. Distances

2. Nature‟s speed limit

3. Acceleration

4. Radiation

5. Is there anybody out there?

6. How would they know we‟re here?

7. Making contact



Speed of light

• 186,000 miles/second = 299,792,458 m/s

• 7x around Earth in one second

• Sun to Earth in about 8 minutes

• Earth to Mars in 3−22 minutes


Distance Scales

• Measurement unit:

1 light-year = distance light travels in one year

1 ly = 5,843,190,000,000 miles 6 trillion miles

It takes Earth about 10000 years to travel 1 ly

around the Sun

Mars Rover Landing

• Landing called “7 Minutes of Terror”


2-Nov-12 World of Science - UFOs 22 from Atlasoftheuniverse.com

You are here

(approximately)

100,000 light years

The Milky Way Galaxy


Distances

• Nearest star is Alpha Centari, 4.3 ly away.

• About 14,000 stars (3500 visible) within 100 ly

• Sun about 25,000 ly from center of milky way.

• To travel to planets orbiting other stars, aliens

(or humans) need

1. to travel near the speed of light

2. to be able to handle long-duration flights

even with these criteria, can probably only visit

a few nearby stars.


Nature’s Speed Limit

• In 1905, Albert Einstein published

the “Special Theory of Relativity”

• One consequence of the theory is the

famous equation:

E = mc2

• Important for this discussion is another

constant: no information or object can

travel faster than the speed of light.


Fermilab, Batavia, IL

protons circulate around accelerator rings

reminder: speed of light c = 186,000 mi/sec

Testing the speed limit

Speed=0.99c=184,500mi/sec

Speed=0.99999999c=185,999.98 mi/sec


High Speed travel

• Fastest manned object:

– Apollo 10: speed 25,000 mph = 0.000037c

• Fastest man made object

– Helios 2 space probe: 158,000 mph = 0.00024c

– This speed was attained by orbiting the sun,

not through rocket propulsion.


Rockets • Rockets work by Newton‟s 3

rd Law

– Burn the fuel, it gets pushed out of the nozzle.

– The fuel pushes back on the rocket, accelerating it.

• Good news

– This works even in outer space

• Bad news

– Have to carry your fuel with you


Acceleration

• Something accelerating at 1g is speeding up at 10 m/s2

– At 1 second: speed 10 m/s

– At 2 seconds: speed 20 m/s

– At 3 seconds: speed 30 m/s

• F-16 pilots can withstand ~6g‟s for a few seconds. (link)

• People might be able to withstand 2-3g‟s for an extended

period of time.

• Space Shuttle

– "Guidance also governs the main engine throttle command so

that acceleration does not exceed 3 g's …. The main engines

are throttled down at approximately seven minutes 40 seconds

into the mission to maintain 3 g's for physiological and

structural constraints."

http://www.youtube.com/watch?v=XM4rS38pd0U


Acceleration

• Imagine we have a spaceship that can reach a

speed of 0.75c

– This is 20,000 times faster than Apollo

• We start at rest on Earth (or near Earth) but we

can only accelerate at 3g‟s or else we‟ll kill all of

the passengers.

• How long does it take for our spaceship to reach

a speed of 0.75c?

• Answer: 116 days

– We need enough fuel to accelerate at 3g‟s continuously

for 4 months!

• Don‟t forget, we must decelerate at the same rate.

– So we need to fire our breaking rockets 4 months prior

to when we want to stop.


Anything prohibitive so far?

• We need

– Radically new technology to accelerate and

decelerate our space ship

– The ability to undergo long duration space

flight (decades to get to the nearest star)

• What about dangers during space flight?

– Radiation!


National Research Council, 2008

“At the present time, given current

knowledge, the level of radiation

astronauts would encounter would not

allow a human crew to undertake a Mars

mission and might also seriously limit

long-term Moon activity.”

International Space Station astronauts

receive a radiation dose that is 27 times

higher than we receive on Earth‟s surface.

The ISS is still protected by Earth‟s

magnetic field and upper atmosphere.


Radiation

• Earth‟s atmosphere and magnetic field

protect us from cosmic radiation.


Radiation

• Radiation would be sufficient to kill humans in

long duration space flight, unless an acceptable

shielding method was developed.

• Perhaps other beings might be less susceptible

to radiation effects.

Questions/Topics

1. Distances

2. Nature‟s speed limit

3. Acceleration

4. Radiation

5. Is there anybody out there?

6. How would they know we‟re here?

7. Making contact



Galaxies

• Our sun is a small star toward the outside of the galaxy, the

Milky Way (a spiral galaxy) containing

approximately 200,000,000,000 stars (2 x 1011

)

• A few others (e.g. Andromeda) visible to naked eye

• Telescopes reveal many galaxies, each ~ 1011

stars

Andromeda Spiral Galaxy m100


You are here

(approximately)

100,000 light years



Views from the Hubble Telescope

• Picture of an area

of the sky (the size

of a grain of sand

held at arm‟s length)

in which there are

no stars visible to

the naked eye!

• Shows visible stars

in the Milky Way and

distant “fuzzy looking”

galaxies

• Estimate:

~1011

=100 billion

galaxies in the universe


Summary

• About 1011

stars per galaxy

2 to 4 x 1011

in the Milky Way

• About 1011

galaxies in the universe

• So we have about: 1011

x 1011

= 1022

=

100,000,000,000,000,000,000,000

stars in the universe.

• More stars in the universe than grains of sand on Earth

• Universe is dominated by light elements (H, He,

Li) but there are plenty of heavy elements that

have been produced by supernovae.


• Question: How many “Earth-like” planets:

• Requirements:

– Single star system (not binary)

– Star should be sunlike (similar to our sun)

– Must have planets

– Must have Earth-like planet

• Estimates (arguable, but you can change them!)

– ~50% are single star systems (not binary)

– ~10% are sunlike (similar to our sun)

– ~10% have planets

– ~10% have an Earth-like planet

4x1011

x 0.5 x 0.1 x 0.1 x 0.1 = 2x108 =200,000,000

Earthlike planets in the Milky Way galaxy alone!!!

[low estimate]

These two estimates are low, reality possibly much higher.

“Good” Places for Life

These two estimates are pretty solid.


How Would We Make Contact?

• Einstein says we can‟t travel faster than the

speed of light.

– Experiments say he‟s right.

– This immediately limits the possibilities for space travel

between solar systems that are light years apart.

• Milky Way is about 100,000 light-years wide

• What can travel at the speed of light?

– Electromagnetic waves! Light, x-rays, radio-waves.

• First contact with an intelligent life form would

most certainly be through electromagnetic waves!


Electromagnetic spectrum

All EM radiation travels at speed of light!


SETI

• Search for Extra Terrestrial Intelligence

– Scanning the sky for all electromagnetic frequencies

– Looking for non-random patterns indicating a

deterministic source.

• Note: Humans have been broadcasting to the

galaxy since the early 20th

century.

– Our electromagnetic waves now reach out some 80 light-

years away from us.

– Anyone farther than 80 light-years would not yet be able

to “see” our broadcasts!

– About 14,000 stars within 100 light-years of us

(=0.00000004% of the Milky Way)

• For signals originating elsewhere, our sensitivity

depends upon location on time.

– To “see” a civilization on the other side of the Milky Way,

they needed to begin broadcasting 30,000 years ago!


How Would We Make Contact?

• First contact with an intelligent life form would most certainly be

through electromagnetic waves!

Allen Telescope array, part of

SETI = Search for Extraterrestrial Intelligence Project

– Scanning the sky for all electromagnetic frequencies

– Looking for non-random patterns indicating a deterministic source.

• You can participate in SETI at Home (link)

http://setiathome.berkeley.edu/


• Humans have been broadcasting to the galaxy

since the early 20th

century.

– Our electromagnetic waves now reach out some 80 light-

years away from us.

– Anyone farther than 80 light-years would not yet be able

to “see” our broadcasts!

– About 14,000 stars within 100 light-years of us

(=0.00000004% of the Milky Way)

• For signals originating elsewhere, our sensitivity

depends upon location on time.

– To “see” a civilization near the center of the Milky Way,

they needed to begin broadcasting 25,000 years ago!

How Would They Know We’re Here?


100,000 light years


Our electromagnetic

footprint is smaller

than this dot!

The rest of the galaxy

has no idea that we are

here!

Sound channels and Roswell

Sound channels

• Waves will “channel” where the wave speed

is lowest.

• In ocean, channel is about ½ mile in depth

– Atmospheric sound channel about 30 miles up


Speed of sound

Ocean

d

ep

th

2-Nov-12

World of Science -

UFOs 49


Summary

• Is there life beyond Earth?

– We don‟t know.

• Has extraterrestrial life visited Earth?

– There is no credible evidence that it has.

– “Extraordinary claims require extraordinary

evidence.” We have yet to see that evidence.

• If we make contact with another

civilization, it will be by electromagnetic

wave.

How would they know we’re here?

• We are looking for exoplanets

– Planets that orbit stars other than our own

– Any in the Goldilocks zone?



UFOs?

• Have we been visited?


UFOs

• Question: Why are they always seen by

untrained observers? Professional

astronomers and astrophysicists observe

the sky daily with sophisticated

equipment have never observed an

extraterrestrial spaceship.

• Question: Why hasn‟t anyone observed

the electromagnetic footprint (radio

waves, gamma rays, light, etc.) of an alien?

The electromagnetic footprint would be

here before the aliens would.


UFOs: Natural Explanation

Some sources that might be misinterpreted:

• Approaching Aircraft (appear to hover)

• Unconventional Aircraft

• High Altitude Balloons

• Venus

• Artificial Satellites

• Reflections Off Clouds

• Optical Mirages

• Meteors

• Uncommon Atmospheric Phenomena (Aurora, Ball

Lightning)

• Secret Military Objects

• Accidents


Material for Life

• Earth is teeming with elements:

– Nitrogen, hydrogen, oxygen, carbon, gold, iron, manganese,

uranium, silver, lithium…

• The big bang (and it‟s aftermath) produced no

element heavier than lithium (atomic number=3).

– Hydrogen, helium and lithium only….nothing heavier.

Atomic # = # of protons

H


“Heavy” Elements

• Heavy elements are crucial for life.

– Carbon, oxygen, nitrogen, iron, potassium…

• Where did the heavy elements come from?

– Normal stars (our sun) typically produce helium from

hydrogen, but also produce some lithium and beryllium

(Be, atomic #=4)

• Elements heavier than beryllium require a higher energy

process to produce them…a supernova.

• Supernovas occur at the end of a large star‟s life cycle.

– The stuff you are made of: carbon, oxygen, silicon, iron,

etc. are supernova remnants!


Supernova

• Expels matter - all heavy elements in the universe (in

you!) are formed in supernovae

• Remnant is a neutron star or black hole

• Radiates more energy than an entire galaxy for a brief

period (months):

– Famous supernovae:

•0 -- The Christmas Star ??

•1054 -- in Crab Nebula, Recorded in China, …..

•1572 -- in large Magellanic Cloud, seen by Kepler

•Pulsars (Neutron Stars) observed now as

remnants of the 1054 and 1572 Supernovae!

•1987 -- in Magellanic Cloud - remnants still

observed


Does Life Develop?

• Experiments show that organic molecules form in

conditions similar to the earliest stages of Earth‟s

development.

– Carbon dioxide, water, nitrogen + energy (heat or

lighting)

• Details of the mechanisms that bring single

celled organisms (like amoeba) from the organic

molecules are under study.

– Let‟s guess that there is only a 1% chance life will

develop on an Earthlike planet. [This is probably a low

estimate. The likelihood to develop life on an Earthlike

planet is probably very high.]

2 x 108 Earthlike planets x 0.01 chance of developing life

= 2 x 106 = 2,000,000 planets with life in the Milky Way.

[this is still a low estimate]


Does Intelligence Develop?

• Large uncertainty.

• See Hobson textbook for a discussion.

– Art Hobson, “Physics Concepts and

Connections”

• The Drake Equation attempt to account for

the likelihood of intelligent life to develop,

as well as the lifetime “time scale”.

– See Origins web site.


2009 Morristown Hoax • Details here

• “The icing on the cake came when the popular

History Channel show UFO Hunters featured the

Morristown UFO as their main story one week.

Bill Birnes, the lead investigator of the show and

the publisher of UFO Magazine, declared

definitively that the Morristown UFO could not

have been flares or Chinese lanterns.”

http://www.skeptic.com/eskeptic/09-04-01/

the physics of ufos - university of illinois · 2-nov-12 world of science - ufos 13 polling numbers...

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