Download Observing the Solar System

Observing the Solar System
??Why is Pluto no longer a
planet??
• According to the new definition, a full-fledged planet is
an object that orbits the sun and is large enough to have
become round due to the force of its own gravity. In
addition, a planet has to dominate the neighborhood
around its orbit.
• Pluto has been demoted because it does not dominate
its neighborhood. Charon, its large "moon," is only about
half the size of Pluto, while all the true planets are far
larger than their moons.
Ideas of the revolving planets
• Greek astronomers
believed that the Earth
is the center of the
universe, which is
called a geocentric (geo
means Earth) system.
• Copernicus in the
1500’s believed that the
sun was the center of
the universe, a
heliocentric (helio
means sun) system.
Meaning the planets
revolve around the sun.
Why do the planets stay in orbit?
• INERTIA and GRAVITY
• Inertia is a tendency of a moving object to
continue in a straight line or a stationary
object to remain in place. The more mass
an object has, the more inertia it has.
• The force of gravity attracts all objects
towards each other. No one is for sure how
gravity works or why it is present.
• As the planets are in orbit around the sun
the sun’s gravity pulls on them while their
inertia keeps them moving ahead.
• Also known as a “long haired star” in Greek
• Comets are chunks of ice, gas, water and
dust.
• Comets look like they have tails because as it
travels through space it warms up and gives
off a cloud of gas around it.
• They follow an orbit around the sun.
• As they get closer to the sun they generally
speed up.
Asteroids
• After the moons, asteroids are the next largest
object in the Solar System.
• They are irregular shaped, some resemble lumpy
potatoes, while others look like rocks.
• Asteroids are made up of iron, nickel, stone or a
combination of them.
• It is believed that asteroids are actually parts of the
solar system that never joined together.
• Most asteroids are in the asteroid belt, a region
that lies between the orbits of Mars and Jupiter.
• Like comets, asteroids orbit the sun.
Meteors – Shooting Stars
• Meteor– streak of light
formed by a space rock and
dust burning up as it
plunges into Earth’s
atmosphere
• Known as meteoroids when
in space.
Meteors Cont……..
• When and IF this rock strikes Earth it is a
meteorite. Most burn up completely before
reaching the ground.
• This occurs when Earth passes through the
tail of a comet or a cloud of dust left behind
by a broken-up asteroid.
Spaced Out Video Clip!
Stars
• Like the sun, stars
are huge spheres of
glowing gas. They
are made up of
mostly hydrogen
and helium.
• They make energy
by nuclear fusion
causing the stars to
shine brightly.
• The main
characteristics to
classify stars are size,
temperature, and
brightness.
Birth and Death of Stars
• All stars begin their lives
as nebulas, a large
amount of gas and dust
spread out in an immense
volume. Gravity then pulls
some of the dust and gas
together causing a
contracting cloud.
• A star is born when the
contracting gas and dust
become so hot that
nuclear fusion starts.
Birth and Death of Stars
• How long a star lives depends on how much
mass it has.
• Less massive stars live longer than more
massive stars.
• Stars with less mass than the sun can live up to
200 billion years.
• When a star begins to
run out of fuel, the
center of the star
shrinks and the outer
part of the star
expands.
• It then becomes a red giant
or supergiant.
• After it runs out of fuel, it
becomes a white dwarf, a
neutron star, or a black hole.
• A black hole refers to the
fact that gravity of black
holes is so intense that not
even light can escape from
them.
Black holes
•When a large star undergoes a supernova
explosion it may collapse in on itself.
•The singularity is a region where the force of
gravity is so strong that light cannot escape.
• http://www.kidsastronomy.com/black_hole.htm
• http://www.nasa.gov/worldbook/blackhole_worldbook.html
• http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html
Our Star….THE SUN!
• Our sun is not a very large star, which is a
good thing because it will have a longer lifespan.
• It rotates on its axis with an average 25
days for each rotation.
• The earth is about 1,650,000,000 football
fields from the sun ( 150 million km)
Our Star….THE SUN!
• The sun’s core reaches about 15 million
degrees Celsius
• There is enough hydrogen for the sun to last a
total of 10 billion years. It is currently about 5
billion years old!
• The sun’s atmosphere has 3 layers:
– Photosphere: Greek word photo means light
– Chromosphere: The middle layer. Chromo means
color.
– Corona: means crown in latin. Like a white halo
around the sun and only visible during eclipses or
use of special telescopes.
Sun spots
• http://www.suntrek.org/solar-surfacebelow/sunspots/how-sunspotsformed.shtml
• Galileo noticed several black spots on
the sun.
• They are usually found in groups and
reappear in the same places about every
11 years.
• Solar flares are sudden
burst of energy in the
form of fire.
• They usually occur over
an area of a sunspot.
• It can give off an
extreme amount of
radiation
• The radiation can be
harmful to astronauts
and disturb radio waves
or compasses on Earth.
Galaxies
• Edwin Hubble helped
astronomers to begin
to understand the
huge size of the
Universe.
• We live in the Milky
Way Galaxy, a group
of about 200 billion
stars.
Three main classes of galaxies
• 1. Spiral Galaxy–
have arms that spiral
outward like pinwheel
• 2. Elliptical Galaxy–
looks like a flattened
ball. They lack gas
and dust not allowing
new stars to form.
• 3. Irregular Galaxy–
does not have a
regular shape