Download Name Class Date Our Solar System The solar system consists of our

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Our Solar System
The solar system consists of our sun and all objects that revolve around it. The major members
of the solar system are the sun and the planets. A number of other bodies are also influenced
by our Sun’s gravity. These include asteroids, comets, meteoroids, and satellites that revolve
around planets. All heavenly objects in the night sky are referred to as celestial objects.
Our sun is a hot, bright ball of gases. It is composed mostly of hydrogen (74%) and helium
(26%). Hot chemical reactions (known as thermonuclear reactions) inside the Sun release
enormous amounts of energy, mostly as light and heat. These reactions occur when the hydrogen
turns into helium.
Earth’s Sun is an average-sized star. The Sun is more than a million times greater in volume than
Earth. The other stars we see in the night sky are like the Sun or even larger but are so far
away that they look like tiny points of light. Distances between stars are vast compared to
distances within our solar system.
Gravity is the force that keeps planets in orbit around the Sun and the Moon in orbit around
Earth. Every object exerts gravitational force on every other object. Gravitational force
depends on how much mass the objects have and on how far apart they are. Gravity is one of
the forces acting on objects in the sky and space.
Most objects in the solar system have a regular and predictable motion. These motions explain
such phenomena as a day, year, phases of the Moon, eclipses, tides, meteor showers, and
comets. For example, our Moon orbits Earth, while Earth orbits the Sun. The Moon’s phases as
observed from Earth are the result of seeing different portions of the lighted area of the
Moons’ surface. The phases repeat in a cyclic pattern in about one month.
The apparent motions of the Sun, Moon, planets, and stars across the sky can be explained by
Earth’s rotation and revolution. Earth rotates on an axis that is tilted at 23.5 degrees. Earth’s
rotation causes the length of one day to be approximately 24 hours. The length of daylight an
area receives varies depending on latitude and season. For example, the North Pole receives 24
hours of darkness and no daylight during its winter season because that is when it is tilted away
from the Sun. Our rotation also causes the Sun and Moon to appear to rise along the eastern
horizon and to set along the western horizon. Earth’s revolution around the Sun defines the
length of the year as 365 ¼ days. The tilt of Earth’s axis and the revolution of Earth around
the Sun cause the seasons on Earth.
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Make sure to answer ALL OF THE FOLLOWING questions on the page below.
1. Planet X is three million kilograms in weight and orbits far away from us. Planet Z is one
million kilograms in weight and orbits right next to us. Explain which planet would affect Earth
more and why. Support your answer with textual evidence from the reading.
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2. Use the information in the reading and
the picture seen here to answer the question
that follows. The times given are the amount
of daylight each line of latitude is receiving.
Explain why the South Pole sometimes receives 24 hours of daylight. Support your answer with
textual evidence from the reading.
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3. Explain what would happen to us here on Earth if there was no more hydrogen left in the Sun.
Support your answer with textual evidence from the reading.
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