Download Introduction To Astronomy

Introduction To
Astronomy
A little overview of what you
might need to know for the
2010 STAR Test
Our Universe
Contains objects that:
Reflect Light and
Objects that give off light
Formed over 12
billion years ago
We live on a planet-an object that
only reflects light from stars
like our sun: SOL
Our SOL-AR System
Milky Way Galaxy
•Our Solar system is
located in one of the
“spiral arms” of the Milky
Way
•The Milky Way is just ONE
of hundreds of billions of
galaxies
•Each galaxy contains
billions of stars
Types of Galaxies
• Spiral
• Elliptical
• Irregular
Stars produce light
• Stars are born in clouds of gas
and dust called Nebulae
• Nuclear Fusion creates Helium
from Hydrogen
• Helium can fuse to form
Carbon
• Heavier elements are formed
from supernova explosions
Basic Star Types
• Smaller red and yellow
stars like the sun are
called main sequence
stars
• Massive bright stars begin
as white and blue stars
• Supergiant stars form
when massive stars die
• Supernova is a massive
explosion of a dying star
Betelgeuse
Distances
 AU (Astronomical Unit) the distance of the
Earth from the Sun (1 AU ∼ 150 million km).
Light Year is the distance that light can travel
in year, which is 9.46 trillion km.
 The Sun is about 93 million miles from the
earth. The star nearest to the Sun is Proxima
Centauri. Proxima Centauri is 4.3 light-years
from the Sun (270,000 AU)
Our Solar System
• Contains other objects that
reflect light and orbit other
bodies called satellites or
moons.
• Our moon: Luna has a lunar
cycle of 28 days in which it
revolves once around Earth
and rotates on its axis in the
same period.
• Comets, asteroids and
meteroids also reflect light.
Meteoroid
A meteoroid is a sand to
boulder-sized particle of
debris. The visible path of a
meteoroid that enters Earth's
atmosphere is a meteor,
commonly "falling star". If a
piece impacts Earth it is
called a meteorite.
Asteroids orbit within an area
between Jupiter and Mars
known as the asteroid belt
Kuiper Belt
The Kuiper Belt is a
disk-shaped region
past the orbit of
Neptune extending
roughly from 30 to 50
AU from the Sun
containing many small
icy bodies. It is now
considered to be the
source of the shortperiod comets.
Comet’s From The Oort Cloud
The Oort Cloud is a
spherical cloud of
comets believed to lie
roughly 50,000 AU, or
nearly a light-year, from
the SunOort Cloud objects
were formed closer to the
Sun than the Kuiper Belt
objects.
Near Earth Objects
 http://www.jpl.nasa.gov/news/spotlights/
200702-neo.cfm
That’s All For Now…