Inner Planets Direct Teach

Comparing Earth to the Other Inner Planets

Open Ended

What did you learn about the
inner planets and what makes
them different from the outer
planets? Why did they form in
these specific areas?

Short Constructed Response

Mercury

Size: Mercury is smaller than Earth and much smaller than the

Sun.

Heat and Light: Mercury does not emit heat or light. It reflects

the Sun's light.

Atmosphere: Mercury has a very thin and almost negligible

atmosphere.

Surface Conditions: Mercury experiences extreme

temperature variations, with scorching hot days and frigid

nights.

Orbit: Mercury orbits very close to the Sun, making it one of

the innermost planets.

Multiple Choice

Which of the following is not true about planet mercury?

•  it is the closest planet to the sun

• It traps heat with its thick atmosphere

• It experiences scorching hot days and freezing cold nights

• It does not emit heat or light

Mercury

The 1st planet from the Sun

• Mercury is the closest planet to the Sun. It's important

because it serves as a point of comparison for

understanding the extremes of temperature and

conditions that can exist in our solar system.

• Its lack of a substantial atmosphere means it

experiences extreme temperature variations, with

scorching hot days and frigid nights.

• Studying Mercury helps scientists understand the

influence of proximity to the Sun on planetary

conditions.

​Rotation

Mercury rotates on its axis in 58.65 days, which is two-thirds of the time it takes to orbit the Sun. This is called a 3:2 spin-orbit resonance. 

• Solar day

  A solar day on Mercury, which is the time it takes for the Sun to return to its highest point in the sky, is about 176 Earth days. This is because of Mercury's slow rotation. 

• Orbit

  Mercury's orbit is elliptical and egg-shaped, taking it as close as 29 million miles and as far as 43 million miles from the Sun. 

Open Ended

Mercury has a unique orbit and rotation pattern. How long does it take for Mercury to complete one rotation compared to one orbit around the Sun? What does this tell you about its day and year?

Venus is often referred to as Earth's "sister planet"

because of its similar size and composition.

However, it's important due to its extreme

greenhouse effect, which has led to a surface

temperature hot enough to melt lead.

Studying Venus provides insights into the impacts of

a runaway greenhouse effect and helps scientists

better understand climate processes and conditions

on rocky planets.

Venus | The Second Planet from the Sun

● Size: Venus is similar in size to Earth.

● Heat and Light: Venus does not emit heat or light. It reflects the Sun's

light.

● Atmosphere: Venus has a thick atmosphere primarily composed of carbon

dioxide, with a runaway greenhouse effect.

● Surface Conditions: Venus has an extremely hot surface due to its thick

atmosphere, with temperatures high enough to melt lead.

● Orbit: Venus also orbits close to the Sun, making it one of the inner

planets.

Venus

RESPONSE CARD

Why is it important
FOR ASTRONOMERS TO STUDY CERTAIN PLANETS, LIKE VENUS? EXPLAIN WHY VENUS IS CONSIDERED EARTH’S SISTER PLANET AND THE
CHARACTERISTICS THAT SEPARATE THE TWO PLANETS.

Complete the Table

Mercury

Venus

Mars

Size: Mars is smaller than both Earth and Venus.

Heat and Light: Mars does not emit heat or light. It reflects the Sun's light.

Atmosphere: Mars has a thin atmosphere composed mainly of carbon dioxide.

Surface Conditions: Mars has a cold, desert-like surface with evidence of past water

flow.

Orbit: Mars orbits at a greater distance from the Sun compared to Mercury and

Venus but is still relatively close.

​Surface of Mars
The surface of Mars is rocky and covered with dust. It has the largest volcano in the solar system, Olympus Mons, which is three times taller than Mount Everest! Mars also has deep canyons, like Valles Marineris, which is over 2,500 miles long. Scientists believe that liquid water once flowed on Mars, as evidenced by dry riverbeds and polar ice caps.

Atmosphere of Mars
Mars has a very thin atmosphere, made mostly of carbon dioxide, with traces of nitrogen and argon. Because of this thin atmosphere, temperatures on Mars can be extremely cold, often dropping to minus 80 degrees Fahrenheit. Unlike Earth, Mars does not have a strong magnetic field, which means it is more exposed to space radiation.

Open Ended

If humans were to travel to Mars, what challenges do you think they would face, and how could we overcome them?

• Size: Earth is a relatively small planet compared to the Sun, which is a

massive star.

• Heat and Light: Earth does not emit its own heat or light but receives

heat and light from the Sun.

• Atmosphere: Earth has a diverse atmosphere composed primarily of

nitrogen and oxygen, which supports life.

• Surface Conditions: Earth has a wide range of surface conditions,

including oceans, continents, and diverse climates.

• Orbit: Earth orbits the Sun at an intermediate distance, neither too

close nor too far.

Earth

White Board

This planet is the largest among the inner planets. Its surface is
mostly covered in water, giving it a bluish appearance from space, and
it rotates every 24 hours.
a. Earth
b. Mercury
c. Mars
d. Venus

Multiple Choice

This planet is the largest among the inner planets. Its surface is
mostly covered in water, giving it a bluish appearance from space, and
it rotates every 24 hours.

• Earth

• Mercury

• Mars

• Venus

Multiple Choice

Which of the following inner planets has the thickest atmosphere?

• Earth

• Mars

• Venus

• Mercury

Multiple Choice

What is the main reason Mercury experiences extreme temperature changes? A) It has a very thin atmosphere.

• It is far from the Sun.

• It has many volcanoes.

• It rotates very slowly

Constructed Response

Compare Venus, Mercury, and Mars to both Earth and the Sun. Identify one key difference

between each of these three planets and Earth, and explain how they differ from the Sun. Use

specific details about their size, heat and light, atmosphere, surface conditions, and orbits in

your response.