Transcript Earth`s Position in the Universe

Unit 1
Earth’s Role as a Body in Space
Welcome to Spaceship Earth!
1. The Effect of Earth’s Rotation:
Say you’re just sitin’ there on
Earth’s equator, all peaceful-like,
minding your own business.
How fast are you moving due to
Earth’s rotation?
Working it Out…
The important point: You travel around the
circumference of Earth once in 24 hours.
Remember…
speed = distance / time
o
o
Distance … 24,888 miles (Earth’s circumference at
the equator)
Time… 24 hr
Let’s plug in the numbers…
speed = 24,888 miles / 24 hr = 1,037 miles/hr
Working it Out…
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Remember
Answer to #1
Just SITTING on the equator you are
moving about 1,000 mph!
You’re moving 1 mile every 3 seconds!
2. The Effect of Earth’s Revolution
(Its orbit around the Sun):
Now you’re standing on the North Pole. Brrrr!!
Why?
Well it’s a place where we can forget about the speed
you’re carried due to Earth’s rotation.
Up here Earth’s rotation just gently spins you around once
in 24 hours on the spin axis you’re standing on.
But you’re still movin’ through space because the entire
Earth is zipping along in its orbit around the Sun.
Assignment #2, if you choose to accept it… How
fast are you moving due to Earth’s orbit around
the Sun?
Hints…
The important point: You travel the path of
Earth’s orbit around the Sun once in 1 year. You can
assume the orbit is a circle whose radius is
93,000,000 miles - the average distance between
Earth and the Sun.
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Circumference of Earth’s orbit around Sun…
2 x Pi x radius: 584 million miles
Time it takes to orbit the Sun once…
1 year = 365.25 days = 8,766 hours = 3.16 x 10 7
seconds
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Speed = distance / time = circumference / time
Speed = 584 x 106 miles/ 8,766 hrs = 66,600 miles/hr Or:
18.5 miles/sec
Answer to #2
STANDING on spaceship Earth, you are
being carried around the Sun at a speed of
18 ½ MILES PER SECOND!!
Say “One Mississippi” ….
There! You just moved 18 ½ miles.
That’s the same as 67,000 miles/hour.
(Maybe you should keep your seat belt on.)
3. The Effect of Earth’s Revolution
Around the Center of the Milky Way
Galaxy:
This one is the toughest ’cause now I’ve relocated you to the north pole
of … the SUN! Here you don’t experience effects 1 and 2 above.
From here you can just watch the spinning Earth as it orbits you.
What? Why did I put you on the NORTH POLE of the Sun?
So I would not confuse you with your motion due to the Sun’s
ROTATION.
(Hey, get with the program …. everything is in motion!)
Assignment #3 is to figure out how fast the Sun (carrying
the entire Solar System along for the ride) is moving in
its orbit around the center of the Milky Way galaxy.
Hints…
The important point: You travel around
the center of the Milky Way galaxy once in 240
million years. Let’s assume the orbit is a circle
whose radius is 28,000 light years (Each light
year is the distance that light travels in a year.)
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Let’s convert 28,000 light years to meaningful
units of miles. One light year = 5.9 trillion miles.
28,000 light yrs x (5.9 x 1012 miles /light yr) =
1.65 x 1017 miles (That’s 165 followed by 17
zeros! That’s a loooooooooooong way across
the Milky Way!)
Mind-Boggling Math
Continued…
Now let’s calculate the circumference of the orbit around
the galactic center…
Distance traveled around the Milky Way…
2 x Pi x radius:
2 x Pi x (1.65 x 1017 miles) = 1.04 x 1018 miles
Time it takes to orbit the center of Milky Way once…
240 x 106 years = 8.8 x 1010 days = 2.1 x 1012 hours = 7.6 x
1015 seconds
Formulas You might need…
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Speed =
distance / time = circumference / time
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Speed =
1.04 x 1018/ 2.1 x 1012 = x 495,000 miles/hr
Or: 140 miles/sec
Answer to #3
For you to orbit the center of the Milky Way once,
in even the unfathomable time of 240 million
years, still requires you to be moving very,
exceedingly, incredibly, *unbelievably* fast!
Right now you are cruising through the galaxy at
495,000 miles/hr! That’s 140 miles/second!
Count out 17 seconds. You just moved the length
of the continental United States - from New York
to San Francisco! REALLY!
What?!!
You’d like to travel the entire diameter of
planet Earth?
Wait 1 minute (actually 57 seconds).
Done.
Look up in the sky!
It’s a bird!
It’s a plane!
It’s Superman!
… big deal…
Just sittin’ there, [insert your name here] is
WAY faster than a speeding bullet!
Welcome to Spaceship Earth!
Lesson 1
You Are Here 
Earth’s Position in
Space
What is Earth’s position in the
hierarchy of space?
I. A-1. Earth’s Position in the
Universe
Earth 
 Solar System (3rd planet from Sun) 
 Milky Way Galaxy (the Orion Arm) 
 Universe!
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http://www.atlasoftheuniverse.com/
Earth’s Motion through
Space
What is the cause of Earth’s
motion through space?
B-1.The Origin of Our Expanding
Universe
• The Big Bang Theory
– The theory that the
universe began as
a point and has
been expanding
ever since
• The 3 yellow galaxies
in each model are…
– Moving apart
en.wikipedia.org
Supporters of this theory believe that all
matter and radiation were compressed into
an extremely small, hot, dense mass that
was in existence only for a fraction of a
second before rapidly expanding.
 Expansion has continued, but at a slower
rate since then.
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Questions remain. Particularly, what
caused it ?
Evidence for the Big Bang
The observation that all other galaxies are
moving away from ours at great speeds
and in all directions.
 The cosmic microwave background
radiation is thought to be evidence of this
expansion.
 The large amount of hydrogen and helium
in the universe.
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http://www.ugcs.caltech.edu/~yukimoon/BigBang/BigBang.htm
http://science.nationalgeographic.com/science/space/universe/origins-universearticle/
A Sense of Time
http://csep10.phys.utk.edu/astr161/lect/sense/sense.html
If we were to compress the time since the
Big Bang into one year, and make the time
of the Big Bang January 1,
 The Earth was formed in mid-September.
 The mammals appeared on December 26.
 All human prehistory (from the first known
stone tools) and history have occurred in
the last 1/2 hour of New Year's Eve.
 Thus, all of human history is but a fleeting
instant on the cosmic timescale.
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The Universe is probably 10-20 billion
years old.
Our Solar System is probably 4-5 billion
years old.
B-2. The Origin of the Milky Way
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Astronomers
hypothesize that the
galaxy began as…
 Spherical clouds in
space
Newer stars have
orbits …
 lying in the plane of
the disk around the
nuclear bulge
http://www.google.com/imgres?imgurl=http://casswww.ucsd.edu/archive/public/tutorial/images/mw.jpg&imgrefurl=http://casswww.ucsd.edu/archive/public/tutorial/MW.html&usg=__
The Milky Way
http://www.atlasoftheuniverse.com/
The Milky Way
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http://www.astropix.com/HTML/D_SUM_S/MILKYWAY.HTM
3. The Origin of the Solar System
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An interstellar cloud forms a solar system by…
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The shape and movement of a new solar system
can be described as …
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condensing as a result of gravity and becoming
concentrated enough to form a star and possibly
planets
A rotating disk with a dense concentration at the
center
A solar nebula is…
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A disk of dust and gas that can form a star
The Eagle Nebula
http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-astro-nebula.html
Star formation has
NEVER been observed!
Big Bang Theory and the END of
the Universe
But how will the universe END? There
are several theories for this as well.
 http//:sciencemusuem.org.uk/educators/cl
assroom_and_homework_rescources/univ
erse_end.aspx
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