Transcript Light Years Away

Light Years Away …..
Distances to Common Celestial
Bodies
How Far is a Light Year????
A light-year is equal to:
 9,460,730,472,580.8 kilometers
 about 5,879,000,000,000 miles
 about 63,240 astronomical units
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The astronomical unit (AU) is a unit of
length equal to the distance from the Earth to
the Sun (about 93 million miles).
How fast is Light??
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Reflected sunlight from the
Moon's surface takes 1.2-1.3
seconds to travel the
distance to the Earth.
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The average distance from
the Earth to the Moon is
384,403 kilometers or
(238,857 miles)
How Long From the Sun to the
Earth???
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It takes
approximately 8.31
minutes for light to
travel from the Sun
to the Earth.
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This distance is
referred to as One
Astronomical Unit
(AU).
What about Pluto???
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It takes
approximately 5.5
light-hours from light
to travel to the
surface of Pluto
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Pluto’s orbit takes it
from 29 to 49 AU
(2.7–4.5 billion mi)
from the Sun
Pluto is mostly brown. No spacecraft has
yet visited this distant object in our Solar
System
What is a Light Day Away??
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The most distant
space probe,
Voyager 1, was
about 28 light-hours
(round-trip light time)
away from Earth in
the week ending
March 9, 2007.
It took that space
probe 30 years to
cover that distance
How fast Can Astronauts Travel???
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If we use the calculations
from the previous slide,
Voyager traveled ½ light
day in approximately 15
years.
If we travel at the speed of
the Voyager then it would
take approximately 30
years to travel one light
day
One light year would take
over 11,000 years!!!!!
The Oort Cloud??
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The Oort cloud is
nearly a light year
from the sun and
approximately 2
light-years in
diameter.
The Oort cloud, is a
spherical cloud of
comets situated
about 50,000 AU
from the Sun.
This is
approximately 1000
times the distance
from the Sun to
Pluto
Sedna is the outmost celestial body in our
Solar System
What About the Nearest Star??

Alpha Centauri is the closest star system to our own
solar system at 4.37 light-years away
(about 25.8 trillion miles or 277,600 AU).
What About Our Milky
Way Galaxy??

The center of our galaxy,
the Milky Way, is about
2600 light years away.
Infrared image of the Milky Way. Many of
the stars in this image
cannot be seen in visible light
The Milky Way Galaxy as seen from
Death Valley, California
What About the Nearest Galaxy??
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The Andromeda Galaxy is a spiral galaxy approximately
2.5 million light-years away.
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It is the nearest galaxy to our
own, the Milky Way.
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Andromeda is the largest
galaxy of a group of galaxies,
which consists of the
Andromeda Galaxy, the
Way Galaxy, the
Galaxy, and
smaller
Milky
Triangulum
about 30 other
galaxies.
How Far Can I See??
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The Triangulum
Galaxy is a spiral
galaxy
approximately 3
million light-years
away
The Triangulum
Galaxy is the most
distant object that
can be seen without
the use of a
telescope
Work Cited
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Slide 3: Surface of the Moon, http://en.wikipedia.org/wiki/Image:Moon-Mdf-2005.jpg
August 25, 2007
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Slide 4:
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Slide 5:
Slide 6:
Slide 7:
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Slide 8:
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Slide 9:
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Slide 10: Infrared Image of Milky Way,
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Surface of the Earth,
http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg August 25, 2007
Surface of Pluto, http://en.wikipedia.org/wiki/Image:Pluto.jpg August 25, 2007
Voyager 1, http://en.wikipedia.org/wiki/Image:Voyager.jpg August 25, 2007
Space Shuttle in Orbit, http://www.archives.gov/press/press-kits/picturing-thecentury-photos/images/space-shuttle-challenger.jpg August 25, 2007
Diagram of the Distance of the Oort Cloud,
http://en.wikipedia.org/wiki/Image:Oort_cloud_Sedna_orbit.jpg August 25, 2007
Position of Alpha Centauri,
http://en.wikipedia.org/wiki/Image:Position_Alpha_Cen.png August 25, 2007
http://en.wikipedia.org/wiki/Image:Milky_Way_IR_Spitzer.jpg August 25, 2007
Milky Way Galaxy from Death Valley,
http://en.wikipedia.org/wiki/Image:Deathvalleysky_nps_big.jpg August 25, 2007
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Slide 11: Andromeda Galaxy, http://en.wikipedia.org/wiki/Image:M31_Lanoue.png
August 25, 2007
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Slide 12: Triangulum Galaxy, http://en.wikipedia.org/wiki/Image:PIA03033.jpg
August 25, 2007