Transcript Cosmic - Science A 2 Z

Cosmic Influences
On Earth
Big Bang
• Estimated to have
occurred 13.7 ± 0.13
billion years
– WMAP (Wilkinson
Microwave Anisotrophy
(variation in
temperature) Probe
– Mapping Universe
• Big Bang – 3.47min
http://www.negotiationlawblog.com/Big%20Bang.jpg
Concepts in Cosmology
• Big Bang Theory:
– Leads to a point of common
origin for all matter
– This point of common origin is
where everything came into
being in a single instant
– Because time and space
originated in the Big Bang,
it did not occur in any
specific location of space
– Every point in the universe
was there when the Big
Bang occurred, and
therefore, every point in the
universe is where the Big
Bang happened
– The cosmic microwave
background radiation is the
echo of the Big Bang.
Concepts in Cosmology
• Big Bang Theory: (cont)
– As the universe expanded, the
wave stretched-out, much like
a phone cord is stretched as
you walk away from the base
– The stretched-out wave would
be very long and have very low
energy
– Two scientists, A. Penzias and
R. Wilson, discovered this
radiation, experimental
verification of the Big Bang.
2 billion years after the big bang
http://apod.nasa.gov/apod/ap960907.html
Concepts in Cosmology
• Future of the Universe
– Big Crunch: If universe is
greater than the critical density,
collective gravity of all the
matter in the universe will stop
expanding and begin to
contract.
– Expanding Universe: If
universe less than the critical
density (current scientific
theory), then universe will
expand forever.
http://apod.nasa.gov/apod/ap080210.html
Universe
• Our universe is
estimated to have 125
– 500 billion galaxies
• The average number
of stars per galaxy is
given as 200 billion
• Error???
• Big 2.10 min
http://www.astro.uio.no/ita/nyheter/HUDF_0304/HUDF_IR_full.jpg
Two Inch Universe
• If the Solar System is
shrunk to 2 inches in
diameter, then
– The nearest star is 2
football fields away
– The nearest star known
to have planets is 6
football fields away
– The Milky Way galaxy
is the size of North
America
http://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Alpha_Centauri_relative_sizes.png/800px-Alpha_Centauri_relative_sizes.png
Milky Way
• Starting with ours –
the Milky Way
• In a plane, the center
found in the
Sagittarius Arm
• Silly name???
http://www.digitalskyllc.com
– Nyx, goddess of the
night sky, dripped milk
• SS in MW
http://www.youtube.com/watch?v=S7GiZMVNB20&feature=related
http://hubblesite.org/gallery/album/entire_collection/pr2004025a/web_print
Our Solar System
• Medium size sun
• 8 planets
–
–
–
–
4 rocky inner planets
4 gas giants
5 dwarf planets
Asteroid Belt between last
rocky and first gas giant
– Kuiper Belt, of which Pluto
is a large member
– Oort Cloud
http://upload.wikimedia.org/wikipedia/commons/c/c4/Planets2008.jpg
Theories of Life
• SETI (Search for Extra-Terrestrial Intelligence)
– Life, including intelligent
life, is found everywhere in
our galaxy as well as other
galaxies
• Rare Earth Hypothesis
– Most solar systems not
suitable for life, but only in
narrow habitable zones
http://cache.io9.com/assets/resources/2008/04/SETI.jpg
Drake’s Equation
• R* = 10/year (10 stars
formed per year, on the
average over the life of the
galaxy)
• fp = 0.5 (half of all stars
formed will have planets)
• ne = 2 (stars with planets
will have 2 planets
capable of supporting life)
• fl = 1 (100% of these
planets will develop life)
• fi = 0.01 (1% of which will
be intelligent life)
• fc = 0.01 (1% of which
will be able to
communicate)
• L = 10,000 years (which
will last 10,000 years)
• N = 10 × 0.5 × 2 × 1 ×
0.01 × 0.01 × 10,000 = 10,
or the number of advanced
civilizations.
Drake’s Equation
• Huge assumptions –
which will greatly
change the estimated
number of intelligent
civilizations in a
galaxy
• Range from 2.31 to
10,000s
http://poweroftheunknown.files.wordpress.com/2006/04/drake2.jpg
Habitable Zone
• Where do we look?
– Not too hot
– Not too cold
– Just right
http://www.art.com/asp/sp-asp/_/PD--10100681/SP--A/IGID--1287057/Goldilocks.htm?sOrig=CAT&sOrigID=7645&ui=04CC46E750A7403884872C1AA8D89201
Habitable Zones
• Greatest diversity and
density of life found
on our planet as we
approach the equator
Amphibiaweb.org/amphibian/countydata.html
Habitable Zones
• Only life known is
Earth
– Possible Mars
– Possible satellites
around Jupiter or
Saturn
• However, are those too
cold
• Possible when sun
swells???
http://www.star.le.ac.uk/edu/Extrasolar.shtml
Habitable Zones
• Not only on Earth and
in our solar system,
but also in our galaxy
– Too close to the center
of the galaxy, too much
radiation
– Too far out on an arm,
not enough radiation
http://forgetomori.com/wp-content/uploads/2007/08/galactic-habitable-zone1.jpg
Proof?
• The only confirmation of
life is on Earth
• Distance to the farthest
reaches of our observable
universe is 46.5 billion
light years
• Billions of galaxies with
billions of stars
• Far fetched to think we are
alone, but technologically
intelligent life?????
http://img159.imageshack.us/img159/6331/phpkahgjyamqo0.jpg
Back to Earth
• What cosmic
influences can impact
(literally) the Earth?
• Meteors
• Asteroids
• Comets
• Sun
• Moon
• Earth
http://prehistoricsillustrated.com/images_kc/earth_impact.jpg
Asteroid Belt
• Total mass smaller
than our moon (but
much of the mass lost)
• 26 large and millions
of small asteroids
• Ceres largest, now
classified as a minor
planet
http://www.arcadiastreet.com/cgvistas/ceres_100a.htm
http://www.semp.us/_images/biots/Biot443PhotoA.jpg
Oort Cloud
• Outer reaches of our
solar system from
Kuiper Belt to
~50,000AU!
• Billions of comets
http://astro.berkeley.edu/~conor/ay250/pluto.html
Sun
• Medium yellow star
• ~10 billion life span
• Primarily hydrogen
with some helium
• Converts ~8 tons of
matter per second to
energy
Flare
E = mc2
http://apod.nasa.gov/apod/ap051005.html
Size 1
Size 2
Energy Output
• Sun produces so much
energy, that one second is
equivalent to the the
current energy used by
world for 500,000 years
• Most of the energy is xray, ultraviolet, visible,
and infrared plus
subatomic and charged
particles
http://dawn.artov.rm.cnr.it/img/spectrum.jpg
Gravity
• From Newton to
Einstein
• Spacetime and Gravity
Earth in Space
• Earth protected by
magnetic fields
– Generated in outer
liquid iron/nickel core
• Earth protected by
atmosphere
– Screens gamma rays,
x-rays and most
ultraviolet rays
http://lpmpjogja.diknas.go.id/kc/e/earth_files/earth-24.jpg
Energy to Earth
•
What day is this?
A.
B.
C.
D.
•
Spring Equinox
Summer Solstice
Fall Equinox
Winter Solstice
Seasons 5.53 min
http://ccrc.unh.edu/~stm/AS/Common/Suns_Rays.JPG
Solar Incidence of Angle
• Light travels in a
straight line
• The curvature of the
Earth forms the
Incidence of Angle
• The same amount of
energy is spread over a
larger area
http://openlearn.open.ac.uk/file.php/2805/S250_3_002i.jpg
Solar Radiation
• Solar radiation
– X-ray – blocked by
atmosphere
– Ultraviolet – mostly
blocked by atmosphere
– Visible – permeates,
partially blocked by
clouds
– infrared – permeates
http://mangalorean.com/circle/images/articles/20061130green4.jpg
Albedo
• Albedo is the fraction of solar
energy reflected from the Earth
back into space
– a measure of the reflectivity of
the earth's surface
• Light soils, heavily vegetated
areas have a high albedo
• Dark soils, open areas have a
low albedo
• Ice, especially with snow on
top of it, has a high albedo
• Water is much more
absorbent and less reflective,
and has a low albedo
http://media-2.web.britannica.com/eb-media/41/112541-004-926AB193.gif
http://www.esr.org/outreach/glossary/albedo.gif
Human Activity
• All organisms change
their environment –
not just humans
• Impact relating to
lowering the albedo:
– Pollution on ice and
snow
– Asphalt and cities
– Clear cut or slash and
burn
http://www.mth.msu.edu/~ivanov/SatelliteP/Big/worldtradecenter_nyc800.jpg
http://www.ncar.ucar.edu/assets/images/arctas_diagram.jpg
Seasons and Sunlight
• What is the solar angle of
incidence for the equator for the
globe on the left?
A. 90°
B. 66.5°
C. 47°
D. 43°
• The globe on the left represents:
A. Summer Solstice
B. Winter Solstice
C. Equinox and cannot tell if
it is the spring or fall
D.
Not enough information
http://www.physicalgeography.net/fundamentals/images/earth_sun_angles.gif
Seasons and Sunlight
• What is the solar angle of
incidence for the equator for the
globe on the right?
A. 90°
B. 66.5°
C. 47°
D. 43°
• The globe on the right represents:
A. Summer Solstice
B. Winter Solstice
C. Equinox and cannot tell if
it is the spring or fall
D.
Not enough information
http://www.physicalgeography.net/fundamentals/images/earth_sun_angles.gif
Direction of Rotation
•
If you are looking
down at the North
Pole, does the earth
spin
A
B
A. Counterclockwise
B. Clockwise
http://www.flutrackers.com/forum/attachment.php?attachmentid=1512&d=1176083504
Eccentricity
• 100,000 year cycle
• Winter in North at
Perihelion, and therefore
shorter than summer
• Low eccentricity of 0.005
• High eccentricity of 0.058
• Mean eccentricity of 0.028
• Present eccentricity 0.017
• Moving towards low
centricity - warming
Perihelion
Aphelion
http://en.wikipedia.org/wiki/File:Eccentricity_half.svg
Obliquity
•
•
•
•
•
•
Tilt of the Axis
41,000 year cycle
Minimum tilt is 21.1º
Maximum tilt is 24.5º
Currently at 23.5º
Tilt is decreasing cooling
http://upload.wikimedia.org/wikipedia/commons/6/61/AxialTiltObliquity.png
Precession
• Wobble like a top
• Completes the wobble
every ~21,000 years
• Other “north stars,
Thuban in Draco and
Vega in Lyra
• Top 10 sec
• Both 33 sec
http://stardate.org/images/gallery/d_procession.jpg
Milankovitch Cycles
• These three cycles, in
combination, can alter
climate
– Eccentricity
– Obliquity
– Precession
• Milankovitch 2.38 min
http://www.cgd.ucar.edu/research/highlights/section/milankovitch.jpg
Questions?