Transcript A Tour Of The Solar System

Galaxies
Galaxies are huge regions of space that
contain the stars, planets, and other
astronomical features
They can have many shapes
Spiral
Elliptical
Irregular
Our galaxy is known as the milky way
galaxy
Pictures of different shaped galaxies
Types of Galaxies
Barred-Spiral
Spiral
Types of Galaxies
Elliptical
Irregular
Milky Way Galaxy
150,000 light years
across
Spiral shaped with 4
arms
We are located in
the Orion arm
Nearest neighbor is
Andromeda (2.2
Million light years)
Light Year
A light year is the the distance light can travel
in one year
Light travels at a velocity of 300,000 km per
second
In one year, light will travel
9,500,000,000,000 km (~10 trillion!)
So if the the Milky Way is 150,000 light years
across, that is 1,500,000,000,000,000,000
km!
OR... If we could travel at the speed of light it
would take us 150,000 years to make it
across the Milky Way
Our Solar System
Origin of the Solar System
The solar system
began as nothing
more than dust
Gravity caused the
dust to condense
and spin
As the cloud gets
hotter and denser
fusion takes place
The fusion results in
the birth of a star
Proto – Planetary Disc
As our star, the sun, is
being formed it is
surrounded by a disc
of debris and gas
These particles interact
and accumulate to
form the planets
When the sun forms it
emits solar wind
This wind pushes
lighter material
outward (the gases)
Life Cycle of a Star
Supernova (SN 1987A)
The Sun
One of more than 100
billion in our galaxy
alone!
Rotates about the
nucleus of the solar
system at about 137
miles/sec
Takes about 200
million years to
complete a rotation
The Sun Cont.
Accounts for 99.8% of the mass of our
solar system
Because it is so massive all of the planets
are captured in its gravity field and orbit it
Composed of 75% hydrogen and 25%
helium
The sun is about 5 billion years old and will
last for about 5 billion more years
The Sun’s Interior
The Sun’s Interior
Gets its energy from nuclear fusion in which
hydrogen atoms are fused together to make
energy and light
The core is about 15 million °C
The Atmosphere of the Sun
Photosphere - inner
layer that is
responsible for the
light
Chromosphere middle layer that
produces the red color
you see at eclipses
Corona - outer layer
that is only visible
during an eclipse
Other Parts of the Sun
Sunspots - dark spots
on the sun that are
areas of gas that are
cooler than gases
around them
Prominences - huge
loops of gas that
connect different parts
of sunspot regions
Solar flares explosions of hydrogen
Geocentric vs. Heliocentric
Prior to Copernicus and Galileo, people
thought that the Earth was the center
of the universe and all things orbited
around the Earth
This is know as the Geocentric model
Based on their observations, Copernicus
and Galileo were able to prove that the
sun was the center of the solar system
This is the Heliocentric model