Download History of the Universe (in 10 minutes)

History of the Universe (in 10 minutes)
https://www.youtube.com/watch?v=-Ip5BAEfZuA
Sun and Space Notes
8.8B recognize that the Sun is a medium-sized star near the edge
of a disc-shaped galaxy of stars and that the Sun is many
thousands of times closer to the Earth than any other star
The Sun
§  The sun is a medium size
star
§  It appears larger than the
other stars because of its
relative nearness to the
earth
§  It consists of about 70%
Hydrogen, 28% Helium and
2% of metals such as iron.
Size
§  The sun is 1,390,000km in diameter
ú  You could fit 1 million earths inside the sun
The planet Venus just passing in front of the Sun
It would take 108 Earths laid side-byside to go across the Sun’s diameter
Characteristics of the Sun – Teacher’s Domain
Relative Sizes
Mass
§  The mass of the Sun
is about 2 x 1030
kilograms
§  It is one of the larger
stars in our Milky
Way galaxy
§  The mass of the Sun
is over 300,000
times greater than
that of the Earth
Distance
§  The Sun is 149,600,000
km (93 million miles) from
the Earth
ú  Since the speed of light
is 303,000 km/sec
(186,000 miles/second),
it takes the light slightly
over 8 minutes to get
from the Sun to the Earth
The Sun’s
Location
It is located in the
outer reaches of
the Milky Way,
which is a grand
spiral galaxy.
Astronomers think
has four major
spiral arms:
Perseus, Cygnus,
Scutum-Crux,
Sagittarius.
The Sun is
located on
Orion’s arm,
which is thought
to be an offshoot
of the Sagittarius
Arm.
Temperature
§  Its temperature is
extremely hot, with the
surface being about
5000° C and the center
core at 15,600,000° C.
ž  The
high temperature in the core, along with
extreme pressure from the Sun's mass, result
in nuclear fusion reactions.
ž  Nuclear fusion converts hydrogen to helium
producing energy
The Sun in Action
§  Astronomy Now – recent solar flare –
March 11, 2015
§  Inside the Sun
Importance of the Sun
§  Without the Sun, the
Earth would not be able
to support life
§  It is the main source of
energy for earth
§  It provides light and
heat
§  It’s necessary for plants
to carry out
photosynthesis
Space, just how big is it?
§  Animation: The Scale of the Universe
Powers of Ten
8.8D model and describe how light years are used to measure distances and sizes
in the universe
The Milky Way
§  The Milky Way is a cluster of
stars, called a galaxy
§  It contains hundreds of billions
of stars
§  If you traveled at the speed of
light for about 2 million years,
you would reach the next
galaxy – the Andromeda
Galaxy
§  There are billions of galaxies
in the universe
Distance to Stars
§  Astronomers use light-years
and astronomical units to
measure distance
ú  A light-year is the distance that
light travels in one year
ú  In space, light travels at a speed
of 300,000km per second
§  A light year is about 6 trillion
miles or 9.5 million million km
Light Years Explained
MIT camera captures light at a
trillion frames per second
How long does it take light to get
from the Sun to the Earth?
8 minutes
It takes 16 minutes to go there and back
§  A light year is
the distance
light travels in
a vacuum in
one year (An
Earth year that
is, 365.25 days)
Stars
Key Idea
The light-year is a unit of
distance, not time!
The Milky Way Galaxy is about 100,000 light years
across, we are about 26,000 light years away from
the center.
Powersof10.com
Astronomical Unit
§  The distance of the Sun to the Earth is called
an Astronomical Unit (AU) and is sometimes
used to denote large distances that are less
than a light year
ž  A light
year is
about 63,241
astronomical
units
Sun to Earth Distance
1 Astronomical
Unit (AU)
93,000,000 Miles
Other planet distances in astronomical units
(from the sun to that planet)
Body
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
AU
.39
.72
1.0
1.5
5.2
9.5
19.2
30.1
39.5
Check for understanding:
§  If the nearest star is 4 light years away
how many miles away is it?
A light year means 6 trillion miles.
Think about that for a moment. If you go outside
tonight and shine a flash light at the sky, in the
next one year that light will travel 6 trillion miles.
6 trillion x 4 light years = 24 trillion miles!
Check for understanding:
§  How long will it take for the light from
that star (that is 4 light years away) to
travel to the Earth?
Four years.
Remember, a light year is the
distance that light can travel IN A
YEAR!
Light year and Time
§  Using a light year as a distance measurement has another
advantage -- it helps you determine age.
§  Let's say that a star is 1 million light years away. The light
from that star has traveled at the speed of light to reach
us. Therefore, it has taken the star's light 1 million years to
get here, and the light we are seeing was created 1 million
years ago.
§  So the star we are seeing is really how the star looked a
million years ago, not how it looks today. In the same way,
our sun is 8 or so light minutes away. If the sun were to
suddenly explode right now, we wouldn't know about it for
eight minutes because that is how long it would take for
the light of the explosion to get here.