4th Grade

1
Our Whirling Planets

• 4th Grade

2
SunOur Brightest Star

• Approximately one million Earths can fit inside
  the Sun.
• The center of the Sun, is made of helium.
• There are dark blotches on the Sun's surface
  called Sunspots. These are cooler areas of the
  Sun.
• 4.5 pounds of sunlight hit Earth every second.

3
Our Solar System

• Consists of nine planets.
• All revolve around the Sun, which is the main
  source of light and heat for these nine planets.
• It is the Sun's strong pull of gravity which
  keeps the planets in orbit around it.

4
MercuryOur Fastest Planet

• The closest Planet to the Sun.
• Only a little larger than our moon.
• It is covered by dust, rocks, and craters.
• It takes 59 days for it to rotate once around its
  axis.
• Mercury can reach a high of 800 degrees and a low
  of about 300 degrees Fahrenheit.

5
VenusOur Hottest Planet

• It takes longer to rotate once around its axis
  than to revolve once around the sun.
• On Venus a day is slightly more than a year.
• About the same size as Earth.
• Has mountains, valleys, and plains.
• The heat is about 450 degrees Celsius.
• Has no water.
• Life as we know it could not survive here. Only
  rocks can handle the high temperature and
  crushing pressure.

6
EarthOur Mother Planet

• 70 of its surface is water the other 30 is
  land.
• Its tilt causes the seasons on the planet.
• Earth is the only planet in the universe which is
  known to support life.
• Earth is almost five billion years old.
• The center of the Earth, its core, is molten.
• Earth is the only planet in the Solar System
  known to be geologically active.

7
MarsOur Angry Red Planet

• The largest volcano in the Solar System is on
  Mars, called Olympus Mons.
• Mars has seasons like Earth. This is caused by
  the tilt of the planet's axis, at a similar angle
  to the tilt of Earth's axis
• Rocks from Mars have landed on Earth from
  meteorite impacts blasting debris through space.
• The average temperature on Mars is about -67 F.

8
Jupiter Our Largest Planet

• Earth could fit into Jupiter over 1300 times!
• Jupiter is made up almost entirely of gas.
• Jupiter's famous Red Spot is a great storm that
  has raged for at least four hundred years.
• Jupiter has a thin set of rings, hardly visible
  from Earth.
• Jupiter has the strongest pull of gravity in the
  Solar System.
• If we were able to stand on the surface of
  Jupiter, we would weigh three times as much as we
  would on Earth.

9
SaturnRings of Beauty

• Saturn is the second largest planet.
• The many moons of Saturn are as different as fire
  and ice. There are at least 24 of them.
• Saturn's rings are believed to be the particles
  of an old moon orbiting the planet, smashed apart
  in a collision about 50 million years ago. A year
  on Saturn would take almost thirty Earth years.
• Saturn is twice as far away from the Sun as
  Jupiter is.

10
Uranus

• It takes just over 84 years on Earth for Uranus
  to orbit the Sun.
• Uranus is the only planet in our solar system to
  rotate on its side.
• If we were able to see Uranus' moons orbiting the
  planet, they would go over and under the planet
  like lights on a ferris wheel.
• Uranus' pale blue color is caused by the methane
  in its atmosphere which filters out red light.

11
Neptune

• Neptune sometimes orbits the Sun further away
  than Pluto making it the most distant planet in
  the Solar System.
• Since its discovery in 1846, Neptune has not yet
  completed a full orbit. In fact, it takes 165
  years for the planet to go around the Sun.
• Neptune has the strongest winds in the Solar
  System, and a dark spot, similar to Jupiter's
  Great Red Spot.

12
PlutoThe Largest Dwarf Planet

• Pluto is the only dwarf planet to once have been
  considered a major planet.
• Once thought of as the ninth planet and the one
  most distant from the sun, it was re-classified
  as a dwarf planet in 2006
• There are many other dwarf planets in our Solar
  System.
• Pluto is smaller than a lot of the other planets'
  moons, including our moon.
• Pluto has not been visited by spacecraft yet we
  only have blurry pictures of its surface even
  the Hubble Space Telescope orbiting the Earth can
  only get grainy photos because Pluto is so far
  from us.
• In 2015, a spacecraft called New Horizons
  (launched by NASA in 2006) will visit Pluto.

13
Solar Eclipse

• A total solar eclipse is not noticeable until the
  Sun is more than 90-percent covered by the Moon.
  At 99-percent coverage, daytime lighting
  resembles twilight.
• The longest duration for a total solar eclipse is
  7.5 minutes.
• At any specific geographic location on the globe,
  a total solar eclipse can occur only once every
  360 years, on average.
• Local animals and birds often prepare for sleep
  or behave confusedly during a total solar
  eclipse. Local temperatures often drop 20 degrees
  or more near totality.

14
Lunar Eclipse

• A lunar eclipse happens when the Moon passes
  through the Earth's shadow.
• Lunar eclipses can only occur at full Moon.
• Lunar eclipses can last for more than three hours
  because the Moon and the Earth are moving slowly
  in relation to each other, and the shadow cast by
  the Earth is so large.
• Lunar eclipses are visible over an entire
  hemisphere, and can never happen more than three
  times a year.