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A walk through the Universe
Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that's just peanuts to space. Douglas Adams,
The Hitchhiker's Guide to the GalaxyEnglish humorist & science fiction novelist (1952 - 2001)
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The Earth
We are here @Career
Launcher, Mysore
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EARTH
Mercury
Venus
Mars
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Earth
Saturn
UranusNeptune
Jupiter
Pluto (not a planet) and its moon Charon
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The Sun
is our nearest star
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The Solar System
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The Milky Way (Our Galaxy)
A hundred, thousand, million stars!
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the Milky Way as seen from the Enterprise
A hundred thousand light years across
Light would take 100 000 years to travel across the galaxy.
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Distances It takes 8 minutes for light to reach
us from the Sun. A light-year is the distance travelled by
light in 1 year.
The Sun is our nearest star. Our next nearest star, Alpha
Centauri is 4 light years away.
The Milky Way is 100 000 light years across.
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The local group of galaxiesAndromeda is the nearest biggalaxy to theMilky Way
Milky Way
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Light from Andromeda takes 2 million years to reach us.
Milky Way
Andromeda
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Local grou
p
The Local SuperclusterHere the local group has shrunk to the size
of the Milky Way in the last slide.
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It left when the dinosaurs were on Earth.
Light from Virgo has taken 65 million years to reach us.
Virgo Cluster
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The Universe is mind-bogglingly big!
The Sun is about 150 000 000 km away from Earth
Bright stars in the night sky are about 1000 000 (1 million) times as far away as the Sun.
The near galaxies are about 100 000 times as far away as the bright stars. 15 000 000 000 000 000 000 km
19NASA
The UniverseThe Universe
Computer Simulation
The observable Universe is 27 Billion light-
years in diameter.
Size and Scale of the UniverseSize and Scale of the Universe
Image courtesy of The Cosmic Perspective by Bennett, Donahue, Schneider, & Voit; Addison Wesley, 2002
EarthEarth
• Planet where we all live
• Comprised primarily of rock
• Spherical in shape
• 12,700 km in diameter
• It would take 17 days to circumnavigate the globe driving a car at 100 km/hr
• At the speed of light, it would take 0.13 seconds to go all the way around Earth.
SunSun
• Star that Earth orbits
• Composed primarily of hydrogen and helium gas
• Uses nuclear fusion in its core to generate heat and light to allow itself to resist the crushing weight of its own mass
• Spherical in shape
• 1.39 Million km in diameter
Earth & SunEarth & Sun• The Sun’s diameter is 109
times greater than that of Earth
• Over 1 million Earths would fit inside the Sun’s volume
• Earth orbits the Sun at an average distance of 150 million kilometers. This distance is called an Astronomical Unit (AU)
• It would take 11,780 Earths lined up side to side to bridge between Earth and Sun.
The Solar System
The solar system consists of the sun, 8 planets and their moons
The 8 planets are Mercury, Venus, Earth, Mars, Uranus, Neptune.
Mercury
Mercury is the planet that is closest to the sun
Mercury does not have a moon A day on Mercury is equal to 176
days on Earth The surface of Mercury is similar
to that of the Earth’s moon
Venus
Venus is the Second planet from the sun
A day on Venus is longer than a year on Venus!!!
The Atmosphere is composed of Carbon Dioxide
Venus has no moons Called Earth’s sister planet
Earth
The third planet from the sun The only planet that supports
life in our Solar System Earth has 1 moon 71% of the Earth’s crust is covered with water
Mars
Fourth from the sun Last of the Terrestrial (Earth-
like) planets Called the Red planet because
of its color Mars has 2 moons; Phobos and
Deimos
Jupiter
Jupiter is the 5th planet from the sun and is the largest planet in the Solar System
Jupiter is the first of the Gas planets
Jupiter has 61 known moons!!!
Saturn
Saturn is the 6th planet from the sun Saturn is best known for its rings The rings around Saturn are made
up of frozen gases, water ice and rock. So the rings are not solid bands around the planet
There are 31 moons orbiting Saturn
Uranus
Uranus is the 7th planet from the sun
It, along with Neptune, are the only planets whose orbits overlap each other
Uranus has 21 moons
Neptune
Neptune is the 8th planet from the sun
A year on Neptune is equal to over 164 years on earth!!
There are 11 known moons, Triton is the largest!
Pluto
Pluto is 9th from the sun. It is not considered as a planet though.
Pluto has 1 moon, Charon Pluto is the rockiest of the
outer planets
Asteroid Belt
BACK
Asteroids are either rocky or metallic objects that orbit the Sun. They are too small to considered planets but are sometimes called planetoids.
They can be anywhere from the size of a pebble up to a 1000km (620 miles) in diameter; the asteroid Ceres is an example of an asteroid that is this large.
They have been found inside Earth’s orbit and all the way out past Saturn’s orbit. Most asteroids, however, are located in the asteroid belt which exists between the orbit’s of Mars and Jupiter.
Asteroids
Comets - small, fragile, irregular-shaped body composed of a mixture of non-volatile grains and frozen gases.
Their orbits are elliptical (oval) or parabolic (U-shaped).
The orbit brings them in very close to the Sun and swings them far out into space, sometimes out past Pluto.
As comets approach the Sun, radiation from the Sun evaporates the ice and gases, creating the lone tail.
The closer to the Sun, the longer the tail of the comet.
The tail of the comet always faces
away from the Sun because of the solar wind coming from the Sun.
Comets
Components of Comets
Example of a Comet’s Orbit Comet 2P/Encke
