Download Our Solar Neighbourhood

Our Solar Neighbourhood
“protoplanet hypothesis” = model to explain
the birth of solar systems
1. cloud of dust and gas begins to swirl
2. most material accumulates in the center
and forms the sun
3. remaining material accumulates in
smaller clumps circling the center to form the
planets
“Protoplanet Hypothesis”
The Sun
• Telescopes with special filters have allowed us
to look at the sun
• The sun is almost 110 times wider than Earth
• Surface of the Sun is about 5500 C, core is
about 15 000 000 C
• Solar wind is release charged particles that
flow from the sun at about 400 km/s (we are
protected by it on Earth due to our magnetic
field)
The Planets
• Those objects that:
– Orbit the Sun
– Have sufficient mass to assume a round shape
– Have their own gravitational pull
SUN > Mercury > Venus > Earth > Mars > Jupiter >
Saturn > Uranus > Neptune
The Planets
• Can be divided into two distinct groups:
– The inner planets (terrestrial – “Earth-like” planets);
tend to be smaller and rockier in composition
– The outer planets (Jovian planets or gas giants); are
large and gaseous and are located great distances
from the Sun
• All the planets, (except Pluto) have been visited
by space probes (unmanned satellites, or remotecontrolled “landers” used to explore areas or
objects in space that are too dangerous to send
humans to)
Other Solar Bodies
• Asteroids = between Mars and Jupiter lies a
narrow belt of small, rocky or metallic
bodies travelling in space
Comets
• Also called “dirty snowballs” are objects made
of dust and ice that travel through space
• They appear to have bright long tails that glow
only when they get close to the Sun; this is
because the Sun heats the materials and gases
are released and pushed away by solar wind
• When comets get close enough to the inner
solar system they can begin to orbit the sun
• Halley’s Comet last visited in 1986 and will
return again in about 2062
Meteoroids, Meteors, Meterorites
• Meteoroid = small pieces of rocks flying
through space with no particular path
• Meteor = when an meteoroid gets pulled into
Earth’s atmosphere by gravity the heat causes
it to give off light (“shooting star”)
• Meterorite = when a meteor actually hits the
Earth’s surface
Eclipses
• Because we know the path of planets is
elliptical, we can accurately predict events
such as Eclipses
• Solar Eclipses occur when the moon passes
between Earth and the Sun and thus casts a
shadow on Earth
• Lunar Eclipses occur when Earth passes
between the Sun and the Moon, casting its
shadow over the Moon
Solar Eclipses
•Occurs 2-5 times a year
•Only lasts a few minutes
Solar Eclipse
http://www.teachersdomain.org/resource/ess05.sci.ess.eiu.eclipse/
Lunar Eclipse
M
E
•Occurs every 6 months
•Can last a few hours
S
Lunar Eclipse