The Great Expanse of Outer Space 9.1 - 9.3

Match the terms to their definitions.

• Constellation

• A star and all the heavenly objects that orbit it

• Galaxy

• A group of stars that forms a picture

• Solar System

• A huge star system

• Milky Way

• The galaxy our sun and solar system belong to; Looks like a giant swirling spiral

A planet is a heavenly body that orbits a (a)   .

• galaxy

• solar system

• star

Which planets are close to the sun and have solid surfaces?

• Inner planets

• Outer planets

(a)   are made mostly of gas and are the farthest from the sun.

• Inner planets

• Outer planets

Which planet orbits the sun in 88 days?

• Mercury
• Jupiter
• Mars
• Venus

Answer explanation

Because Mercury is closest to the sun, its orbit is the shortest. There are only 88 days in Mercury's year.

Which planet takes 165 Earth years to orbit the sun?

• Mars
• Saturn
• Neptune
• Jupiter

Place each planet in the correct category.

Groups:

(a) Inner planets

,

(b) Outer planets

• Neptune

• Uranus

• Venus

• Mercury

• Earth

• Saturn

• Mars

• Jupiter

Answer explanation

Inner planets are the closest to the sun with solid surfaces. Outer planets are the farthest from the sun and are made mostly of gases.

Tags

NGSS.MS-ESS1-3

The Earth rotates on its axis every (a)   .

• 24 hours

• 365 days

• month

Answer explanation

The Earth rotates on its axis from West to East, and this is why the sun seems to rise in the East each morning and set in the West each evening.

Match the following terms to their definitions.

• Axis

• An instrument using the Earth's position to tell time

• Sundial

• An imaginary line through the center of the Earth from the North Pole to the South Pole

• Rotate

• To Spin

• Revolve

• To orbit a central point

Answer explanation

Depending on the Earth's position, the gnomon's shadow told people what time it was by pointing to a number on the dial plate.

How could people determine the day of the month a long time ago?

• By counting the stars
• By watching the moon

• By using a calendar

Tags

NGSS.MS-ESS1-1