Transcript Learning About Stars

StarStories
3rd Grade Astronomy
The Stars in Ancient Times
People have looked at the
sky for thousands of
years. When ancient
people looked up, the
stars looked almost
identical to what we see
today.
Stars do change, but they
change VERY slowly. We
will probably not notice
changes to the stars in
our lifetime.
Viewing Stars and Planets
These ancient people did
not have the same
technology and tools that
we have today. But they
were able to notice the
difference between stars
and planets. What do you
think they saw in the sky
that told them that there
was a difference?
Copernicus – One of the first astronomers that
believed in a “heliocentric” system. Helio =
sun…so a system that moves around the Sun.
Before that, people believed in a “geocentric”
idea. Geo = Earth…so Earth at the center.
A Whole Lot of Movement
First, we need to
remember that Earth
is doing A LOT of
moving around.
In this satellite photo,
we can see the line of
light and shadow that
makes day and night.
http://yoga108.org/images/blog/2006/earth_day_night_big.jpg
Rotation
Earth rotates on its axis.
Part of the Earth
faces the sun, while
the other part of Earth
is in shadow.
Earth’s rotation is why
we have night and
day.
http://starchild.gsfc.nasa.gov/Images/StarChild/questions/dayandnight.gif
Revolution
Earth revolves around
the sun. The path that
Earth and other
planets follow is
called an orbit.
http://www.mathsisfun.com/measure/images/earth-orbit-sun.gif
Planets Moving
All the planets do the
same thing, but some
planets take less time
than Earth to travel
around the Sun, while
some planets take
longer.
But this is different than
the stars…
http://www.redorbit.com/modules/reflib/article_images/6_15cc05865f89c4801c5ff2a85d74a93c.jpg
Star Movement
The stars do not travel
around our Sun,
which is also a star.
BUT, we need to
remember that our
solar system is on the
edge of the Milky Way
Galaxy…which IS
moving in space.
http://chadlewis.net/tag/heaven/
Star Movement
So why do you always hear
that the stars don’t move?
It’s because we are
traveling together in a
group and the stars’
positions stay the same in
that group….while the
planets move around the
stars. The stars appear to
move because the
EARTH is moving.
http://theapblog.wordpress.com/2007/04/16/tutorial-star-trails/
Earth’s Rotation
Stars appear to travel in
the sky in the same
direction as the sun—
from east to west.
This is because our
Earth is spinning the
opposite—the Earth
spins west to east—or
counterclockwise.
Earth’s Rotation
Here is another
animation of the Earth
rotating.
Earth and Stars -- Opposite
Pretend you are
standing looking at
the night sky…
The Earth movement is
shown with a blue
arrow.
This makes the stars
seem to be moving
the direction of the
red arrow.
Earth and Stars -- Opposite
Here is a video that
shows a time-lapse
video of the night sky.
You will see the stars
moving from left to
right (east to west).
Remember, the Earth is
actually moving west
to east.
http://vimeo.com/4505537
Milky Way – Not Just a Candy Bar
In the video, did you
notice a collection of
cloud-looking
formations?
This is actually our
galaxy…the Milky
Way.
Our Solar System is at
the edge of the Milky
Way.
http://scrapetv.com/News/News%20Pages/Science/Images/milky-way-brunier.jpg
Back to the Ancients
Ancient people tracked
the stars.
They noticed that the
stars stayed grouped
together in the sky.
They began grouping
the stars in patterns,
called constellations,
and making up stories
about them to help
people remember.
http://www.starsurfin.com/constellations/images/constellations_figures.jpg
But Wait!!
There were “ancient” people
in all different parts of the
world.
Some lived on the top half
of the Earth, while others
lived on the bottom.
Would they see the same
thing in the night sky?
Talk to a partner about your
thinking…
http://imagecache5.art.com/p/LRG/16/1602/QG2FD00Z/constellations-of-the-zodiac.jpg
Hemispheres of Earth
The Earth is divided into
two hemispheres.
The equator is the
widest part of Earth.
Above the equator is
the Northern
Hemisphere.
Below the equator is the
Southern
Hemisphere.
View from the Hemispheres
Stars are not just
“above”…they are
everywhere, and every
direction.
If we live in the Northern
Hemisphere, we can only
see part of space. We
can’t see some of the
same stars as the people
on the Southern
Hemisphere.
Northern Hemisphere
This Skymap or
Skychart shows the
constellations visible
in the Northern
Hemisphere.
However, what you can
see depends a little
on where you are in
the Northern
Hemisphere.
Southern Hemisphere
The constellations in
this skychart probably
don’t sound as
familiar. That’s
because we can’t
view most of them
from the Northern
Hemisphere….maybe
just the ones at the
edge. Why?
Compare Hemispheres
What things do you notice when we compare both charts?
Pole Star
The Southern
Hemisphere seemed
jam-packed with
stars toward the
middle.
But the Northern
Hemisphere has one
thing the Southern
Hemisphere
doesn’t…a “Pole
Star”
Polaris – Our Pole Star
Pole Star
Polaris (aka, the North Star) is
almost directly above the
North Pole.
When the Earth rotates, Polaris
does not appear to move like
the rest of the stars.
In fact…all of the stars seem to
circle Polaris.
Look at the Star Trail photo. The
camera was left on to record
the movement of the stars.
The North Star doesn’t
appear blurry or have a trail
because it is in the same
position the whole time.
Polaris is at the center!
http://media.ebaumsworld.com/mediaFiles/picture/663781/80524364.jpg
Polaris
Ancient people used
Polaris to help them
find their way.
Since Polaris appears
in the same spot in
the sky, they could
tell which way was
north.
http://www.everett-white.com/images/20080827150809_the%20north%20star.jpg
How to Find Polaris
First, you need to find the Big
Dipper. The Big Dipper is
not a constellation itself. It is
an asterism. An asterism is
a group of stars that are
part of another
constellation.
The Big Dipper is part of Ursa
Major (the Great Bear).
It is fairly easy to find in the
sky.
The Big Dipper
How to Find Polaris
The Big Dipper could be
facing any direction.
The Big Dipper
How to Find Polaris
It could be going up and
down.
How to Find Polaris
It could be leaning.
How to Find Polaris
It could be upside down.
How to Find Polaris
Which ever direction it is
facing, find the two end
stars in the cup of the
dipper.
The Big Dipper
How to Find Polaris
Follow them away from
the Big Dipper
How to Find Polaris
The bright star across
from the cup of the Big
Dipper is Polaris.
How to Find Polaris
Polaris is in the constellation Ursa Minor….or
commonly known as the Little Dipper.
Ursa Major
The Big Dipper, an asterism, is part of a larger
constellation called Ursa Major.
http://starryskies.com/The_sky/constellations/ursa.major2.jpg
Ursa Major
Ursa means “bear” and major means “great”.
Great Bear….can you see the bear in this picture?
http://starryskies.com/The_sky/constellations/ursa.major2.jpg
Constellations
There are many other
constellations in the sky.
Though we usually talk
about the constellations
with their Greek and
Roman names and stories,
people of many different
cultures had their own
names and stories to go
with the patterns they
found in the stars.
http://hsci.cas.ou.edu/images/jpg-100dpi-5in/19thCentury/Aspin/1825/Aspin-1825-UrsaMajor.jpg
Cassiopeia
Another constellation across from Ursa Major and
past Ursa Minor is Cassiopeia.
Circumpolar Constellations
Some constellations can be seen all the time, no matter what
time of year. These are called “circumpolar”
constellations…around the pole.