Transcript Galaxies

Galaxies – Collections of billions of stars and their systems (existing telescopes
can currently ‘see’ over 100 billion different galaxies)
Spiral - shaped like a disk, usually
with a bulge in the center and with
arms that spiral outwards as the
galaxy rotates. Spiral galaxies tend to
contain more middle-aged stars and
clouds of gas and dust.
Elliptical - Elliptical galaxies contain
older stars and very little gas and
dust. They can be different shapes
ranging from round, to flattened,
elongated spheres.
Irregular - an undefined shape and
has lots of young stars, dust and gas.
Galaxies – Collections of billions of stars and their systems (existing telescopes
can currently ‘see’ over 100 billion different galaxies)
The Milky Way is a spiral galaxy.
Our Sun is 28,000 light years from
the galactic center, taking about
220 million years to complete an
orbit.
Sun’s Position in the Universe
Click here for a field trip
through the Universe.
Compare the purposes of the tools and the
technology that scientists use to study space.
telescope
• visible light (refracting, reflecting) (Earth-based, space-based)
• radio
• IR, UV, x-ray, gamma
Spectroscope – This is the only one that will be on Thursday’s test.
The rest will be done later.
satellite
probe
flyby
orbiter
lander
rover
astronaut/space ships and stations
spectroscope
Sol – our star’s name, hence the
phrase ‘Solar System’
Sol’s satellites – Do you know them
in order? – a satellite is an object
that orbits, or revolves (not rotates),
around another object.
This artist’s rendition attempts to
show the size to scale of each of
Sol’s satellites in comparison to Sol.
The artist has also included some of
the satellites of the planets.
Defend: Earth and our moon are
both satellites.
8-4.1.
“Summarize the characteristics
and movements of objects in the
solar system (including planets,
moons, asteroids, comets, and
meteors/meteoroids/meteorites).”
Note: You must also now include
SSSB and dwarf planets!
You took notes on all of these last
week. Is your notebook current?
Asteroids, comets, meteoroids (review)
Rock and ice are the main ingredients of asteroids, comets and
meteors. These flying rocks orbit the sun and sometimes come
close enough to Earth to see.
Asteroid:
Comet:
•made of rocky
and/or iron-nickel
material
•Long, elliptical orbit –
usually travel beyond the
gas giants
•most are found in
an orbit between
Mars and Jupiter
•Some asteroids
have other
asteroids orbiting
them (their own
moons)
•like a ball of rock and dirty
snow
•frozen gases and dust
begin to heat when near sun
and cause a long tail of
vaporized gases, dust and
debris to flow behind them.
• Debris remains littered
throughout solar system
Meteoroid:
• usually a piece of
comet debris.
Meteor:
• comet debris entering
Earth’s atmosphere;
usually the size of a grain
of sand to a softball
• meteor burns when falling
through the atmosphere;
“shooting star”
• Meteorite: meteor that
doesn’t burn up all the way
and hits the earth’s surface