Planet
Distances
Teacher’s introduction to the material:
Students may
know that planets are at different distances from the Sun, but are not able to
visualize the implications the distances make for the planets. This lesson
helps make the educational material concrete, thus easier to understand for
young children.
Instruction:
- Tell the students that all
the planets in our solar system orbit the Sun, but they are at different
distances. Discuss with the students how the distance from the Sun would influence the length of a year (one orbit around the sun); how the speed of rotation would influence the length of a day on the planet and how rotation direction would influence where the sun rises and sets. (Does the sun rise in the the east and set in the west on every planet?)
- Starting at the Sun post;
have the students pace off each planet post and read the information about the
planet. Continue the discussion about distance, size and rotation as they
progress through the solar system.
Sun
The Sun is
the closest star to Earth. The Sun is 92.96 million miles from Earth. This
distance is known as an astronomical unit and sets the scale for measuring
distances across the solar system. The Sun is a huge sphere of mostly ionized
gas, that supports life on earth. The interactions between the Sun and the
Earth drive the seasons, ocean currents, weather and climate on Earth.
Mercury
Mercury
speeds around the Sun every 88 days, traveling through space at nearly 31 miles
per second which is faster than any other planet. The time between one sunrise
and the next sunrise is 175.97 Earth days. Mercury has no atmosphere to
regulate surface temperature. Instead of an atmosphere Mercury has an
“Exosphere” made up of hydrogen, helium, sodium, potassium, calcium and
magnesium.
Venus
Venus and
Earth are similar in size, mass, density, composition, and gravity. Venus is
covered by a thick, rapidly spinning atmosphere, creating a scorched world with
temperatures hot enough to melt lead and surface pressure 90 times that of
Earth. Venus’s atmosphere consists mainly of carbon dioxide, with clouds of
sulfuric acid droplets. The thick atmosphere traps the Suns’ heat, resulting in
surface temperatures higher than 880°F. Venus rotates retrograde (east to west)
compared to Earth that rotates prograde (west to east). Standing on Venus the
Sun would rise in the west and set in the east. A year on Venus is about 225
Earth days long. The time between one sunrise and the next sunrise is 116.75
Earth days long.
Earth
Earth is the
only planet in our solar system known to harbor life. Earth is the third planet
from the sun and the fifth largest planet in the solar system. The four seasons
on earth are the result of the axis of rotation being tilted 23.45° with
respect to the plane of the Earth’s orbit around the sun. During part of the
year, the northern hemisphere is tilted toward the Sun and the southern
hemisphere is tilted away, producing summer in the north and winter in the
south. Six months later, the situation is reversed; with the northern
hemisphere tilted away from the Sun and the southern hemisphere tilted toward
the Sun, producing winter in the north and summer in the south. The atmosphere
of the earth consists of 78% nitrogen, 21% oxygen, and 1% other ingredients.
Mars
Mars is a
rocky planet about half the size of Earth. Mars has two small moons. Like
Earth, Mars experiences seasons due to the total tilt of its rotational axis.
The cold temperatures and thin atmosphere of Mars do not allow liquid water to
exist at the surface for long. The time between one sunrise and the next
sunrise is 24.660 Earth hours.
Asteroid Belt
Asteroid
Belt - asteroids are rocky remains from the early formation of the solar
system. Asteroids range in size from 590 miles in diameter to .6 miles in
diameter the C – type asteroids consist of clay and silicate rocks. The S –
type asteroids are made up of silicate materials and nickel – iron. The M —
type asteroids are metallic (nickel – iron). Scientist on earth monitor the
asteroid belt because asteroids that approach Earth’s orbit may pose an impact
danger.
Jupiter
Jupiter is
the largest and most massive planet in our solar system. Jupiter’s atmosphere
is composed mostly of hydrogen and helium. Jupiter has four large moons and
many small moons. In total Jupiter has more than 60 moons. In 1979 NASA’s
Voyager 1 spacecraft discovered the rings of Jupiter. The time between one
sunrise and the next sunrise is 10 Earth hours.
Saturn
Saturn’s
atmosphere is made up of mainly hydrogen and helium. Wind speeds in the upper
atmosphere reach 1600 feet per second in the equatorial region. In contrast,
the strongest hurricane – force winds on Earth top out at about 360 feet per
second. The superfast winds on Saturn, combined with heat rising from within
the planet’s interior, cause the yellow and gold bands visible in the
atmosphere. Saturn has seven main rings and 53 known moons.
Uranus
Uranus was
the first planet found with the aid of a telescope in 1781. It takes Uranus 84
Earth years to complete one orbit around the sun. Uranus rotates retrograde
(east to west) compared to Earth that rotates prograde (west to east). The
atmosphere is mostly hydrogen and helium, with a small amount of methane and
traces of water and ammonia. Uranus gets its blue – green color from methane
gas in the atmosphere. Uranus has two sets of rings and 27 known moons.
Neptune
Neptune was
the first planet located through mathematical predictions rather than through
regular observations of the sky. It is invisible to the naked eye because of
its extreme distance from Earth. Neptune orbits the sun once every 165 Earth
years. Neptune has six known rings and 13 known moons.
