Download How big is our Solar System?

How big is our Solar System?
SOLAR SYSTEM SCALING
ACTIVITY
To REALLY help you visualize how
BIG it is, let’s make a scale model
of our solar system
• We need to know the actual distances of
each planet’s orbit from the sun
• We need to know the actual size of each
planet
• Then we’ll determine a scale factor that
will allow us to create the biggest possible
scale model in our immediate locale
Where and how will we create our
scale solar system?
• Start at the corner of Jefferson and Sanger
and walk east past the Freshman HS and
the HMS Central Office Building
• Measure distances in meters with meter
tapes
• Leave a marker at each location
What’s next?
So, how do we know how far to walk and
how big each planet/body should be?
How far is it to the Central Office building?
Create a table
Planet
/Body
Mercury
Actual
distance
(km)
58,000,000
Venus
108,000,000
Earth
150,000,000
Mars
228,000,000
Asteroid belt
Jupiter
780,000,000
Saturn
1,427,000,000
Uranus
2,900,000,000
Neptune
4,500,000,000
Pluto
5,900,000,000
Scaled
Distance Scale size
distance from last of planet
(m)
planet (m) (mm)
Let’s try some out—DON’T fill out
your table until instructed to do so!
NOTE: NEITHER PLANET SIZES NOR DISTANCES BETWEEN ARE TO SCALE!
Asteroid Belt
Here’s the info you need for the asteroid belt:
Distance from sun to the middle of the asteroid belt
is 404,000,000 km
For our scale, it will be located at 22.1 meters.
The biggest asteroid, Ceres, is way too small at 914
km (568 miles) to show in this activity, so leave the
actual size and scaled size of the PLANET/BODY
blank.
The total mass of all the asteroids
is only 4% of the Moon’s mass!
Completed table
Planet
/Body
Mercury
Actual
distance
(km)
Scaled Distance Scale size
distance from last of planet
(m) planet (m) (mm)
58,000,000
2.91
Venus
108,000,000
5.43
2.52 0.6 celery seed
Earth
150,000,000
7.51
2.08 0.6 celery seed
Mars
228,000,000
11.4
3.89
Asteroid belt
404,000,000
22.1
10.7
Jupiter
780,000,000
39.0
16.9
7.1 big pea
Saturn
1,427,000,000
71.6
32.6
5.8 small pea
Uranus
2,900,000,000
144
72.4 2.3 peppercorn
Neptune
Pluto
4,500,000,000
5,900,000,000
--
226
82.0
297
71.0
0.2 teeny dot
0.3 dot
2.2 peppercorn
0.1 teeny dot
Origin of the Solar System
• About 4.5 billion years ago, there was a
rotating cloud of dust and gas (mostly
hydrogen) quietly hanging about in our
neighborhood of the galaxy. This cloud was
a nebula.
• At the center of the rotating nebula, material
drew together because of gravity, and our
Sun was born. The rest of the dust and gas
settled into a disk surrounding the sun.
• Something disturbed this nebula and
caused it to start clumping together.
•Planetesimals are small, irregularly
shaped bodies formed by colliding matter.
•As time went on, the planetesimals collided
with each other, forming larger bodies.
How can the Planets be Grouped?
1 AU = 1 astronomical unit = 1.50 x 108 km = distance from Earth to the sun
Terrestrial Planets
• Mercury
• Venus
• Earth
• Mars
All of these planets are small and rocky.
They are MUCH smaller than the Jovian
planets. Their densities are about 5 times
that of water due to their chemical makeups
of metals and solid minerals.
Jovian Planets
• Jupiter
• Saturn
• Uranus
• Neptune
All of these planets are gas giants. They
are mostly composed of gases such as
hydrogen, helium and methane and ices
of water and ammonia. (Saturn would float
on liquid water!) They also rotate MUCH
faster than the terrestrial planets do.
Planetary Composition, Distance
from the Sun, and Melting Point
Asteroid Belt
• Between the Terrestrial and Jovian planets
is the ASTEROID BELT. Asteroids are
small rocky bodies that range in size
from a dust particle to a few hundred
kilometers.
• Ceres is the largest and classified as a
dwarf planet at 950 km in diameter.
Comets
Halley’s
 Comets are small
bodies made of rocky
and metallic pieces
held together by
frozen gases. A
common name is
“dirty snowball.”
 Comets generally
revolve about the sun
in elongated
elliptical orbits.
 For most of its life, a comet
remains frozen, but as it
approaches the sun, the frozen
gases begin to vaporize.
The coma is the fuzzy, gaseous component
of a comet’s head.
A small glowing nucleus with a diameter of
only a few km can sometimes be detected
within a coma. As comets approach the sun
most develop tails that extend for millions
of km.
Dust Tail and Gas Tail
The streams of dust and
gas each form their own
distinct tail, pointing in
slightly different directions.
• The dust tail often forms
a curved tail called the
antitail.
• The gas tail always
points directly away
from the Sun, as the
ionized gas is more
strongly affected by the
solar wind than is dust.
Comet McNaught, 2007
Jan. 20, Australia
Jan. ?, Chile
Jan. 11, Los Alamos
Jan. 13,
Germany
Comet Sources in
the Outer Solar System
Kuiper Belt
Outside the orbit of Neptune is the Kuiper
Belt. Most comets from this region have
short period, nearly circular orbits that
lie roughly in the same plane as the
planets.
Oort Cloud
Comets with long orbital periods appear
to be distributed in all directions from the
sun, forming a spherical shell around
the solar system called the Oort Cloud.
Meteoroids
A meteoroid is a small, solid particle that
travels through space.
A meteor is the luminous phenomenon
observed when a meteoroid enters
Earth’s atmosphere and burns up,
popularly called a shooting star.
A meteorite is any portion of a meteoroid
that reaches Earth’s surface.
Meteoroids
Most meteoroids come from any one of the
following three sources:
(1) Interplanetary debris left over from the
formation of the solar system,
(2) Material from the asteroid belt, or
(3) The solid remains of comets that once
traveled near Earth’s orbit.
• Most repeating
meteor showers are
associated with
debris left by a
comet.
• Each year, as Earth
crosses the path of
the comet, pieces of
debris are swept up
by Earth’s gravity
and burn up in the
atmosphere.
Meteorites
• Meteorites are classified into three major
types: stony (94%), iron (5%), and stonyiron (1%).