Read & Think · Space Science

The Cold Red Desert

A rusty world where the wind never quits and the night sky holds two moons.

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Date

A real panorama of Mars' rusty, rock-strewn desert captured by NASA's Curiosity rover — the kind of cold red landscape robots explore in our place. Photo: NASA/JPL-Caltech/Malin Space Science Systems, public domain.

Picture a desert that stretches to the horizon, painted a deep rusty orange, where the air is so cold it would freeze your breath in a heartbeat. That is Mars, the fourth planet from the Sun and one of Earth's next-door neighbors in space. People call it the Red Planet, and once you learn why, the name never lets go.

Mars looks red because of rusty iron in its ground — the same rust that turns an old nail orange. Wind carries this reddish dust everywhere, giving the whole planet a warm color that hides a cold truth: the average temperature is about minus 85 degrees Fahrenheit, far below freezing.

The air on Mars is thin and made mostly of carbon dioxide, with some nitrogen and argon — nothing a person could breathe. Yet that thin air still moves. Spiraling winds called dust devils twist across the surface like tiny tornadoes, and giant dust storms sometimes grow so huge they cover the entire planet.

Even though it is smaller than home — Mars is about half the size of Earth — it feels oddly familiar. It has seasons, polar ice caps, volcanoes, canyons, and weather, just like our world. One canyon, Valles Marineris, runs more than 2,000 miles long, dwarfing anything on Earth.

A day on Mars is close to ours, lasting 24.6 hours. But a year stretches on for 687 Earth days — almost twice as long as one of ours. And when night falls, two moons rise instead of one: their names are Phobos and Deimos.

Is there water? Scientists have found signs of ancient floods, but today water mostly hides in icy dirt and thin clouds. A world this cold and airless is why we have not sent people — yet. Instead we send rovers: robot explorers like Curiosity, Perseverance, Spirit, Opportunity, and Sojourner that roll across the rocks for us.

One robot even took flight: a small helicopter named Ingenuity made 72 flights in just under three years before its mission ended in early 2024. Each rover and flyer is a scout, learning the red desert one step at a time, so that someday humans might finally follow.

Source: NASA Space Place, "All About Mars" (spaceplace.nasa.gov) — public domain.

The Cold Red DesertComprehension

Check that you read it

Fill each blank with the right word from the box.

Word bank: iron · devils · Phobos · rovers · miles

Mars looks red because of rusty iron in its ground.
Spiraling winds called dust devils twist across the surface like tiny tornadoes.
Mars has two moons named Phobos and Deimos.
Because Mars is so cold and airless, we send robot explorers called rovers instead of people.
The giant canyon Valles Marineris runs more than 2,000 miles long.

Choose the best answer

Based on the article, what is the main reason we explore Mars with robots instead of people right now?
- A. Mars is too far away to photograph
- B. Mars is extremely cold with air people cannot breathe
- C. Mars has no solid ground to stand on
- D. Mars is bigger than the Sun
Why does Mars look red?
- A. It is covered in red water
- B. Rusty iron in its ground
- C. It glows red from the Sun's heat
- D. Thick red clouds hide it
How long is one year on Mars compared to one year on Earth?
- A. Half as long
- B. Exactly the same
- C. Almost twice as long
- D. Ten times as long

The Cold Red DesertVocabulary

Word cross

Use what you read to fill the puzzle. Every clue is answered somewhere in the article.

1P

2F

H

R

3M

O

4D

E

A

B

E

5C

U

R

I

O

S

I

T

Y

Z

A

S

M

6I

R

O

N

7D

O

N

Y

U

S

G

8M

O

N

S

N

T

Across

NASA rover that rolls across Mars gathering information for scientists.
Rusty metal in the ground that gives the planet its red color.
Phobos and Deimos are the planet's two of these.

Down

One of Mars' two moons, the partner of Deimos.
Mars' average temperature of minus 85 degrees is far below this.
The Red Planet, fourth from the Sun, that this piece is all about.
The other moon of Mars, named alongside Phobos.
Valles Marineris is a giant one, more than 2,000 miles long.
Spiraling 'devils' made of this blow across the surface like tiny tornadoes.

The Cold Red DesertCritical Thinking

Now think

There isn't one right answer here. Explain your thinking — the reasons matter more than the answer.

1 · The article says Mars 'feels oddly familiar' to Earth. What evidence does the writer give for that, and do you think it is enough to call the two planets alike? Use details from the piece to back up your view.

For the teacherA strong answer points to specific evidence the article gives (seasons, polar ice caps, volcanoes, canyons, weather, a nearly matching day length) and weighs it against big differences (deadly cold, unbreathable air, a much longer year) before reaching a reasoned judgment.

2 · The article links Mars' cold, thin, unbreathable air to our choice to send robots instead of people. Is the cold really the only cause? What other reasons might explain that choice, even if the article does not name them?

For the teacherA strong answer recognizes that the freezing, airless conditions are one cause the text names, then reasons beyond it to other plausible factors such as the great distance, danger, cost, or limits of current technology, showing they are not treating a single cause as the whole story.

3 · Rovers and the helicopter Ingenuity explore Mars for us, but they cannot do everything a human could. Name one trade-off of sending robots instead of people: something we gain and something we give up.

For the teacherA strong answer names a clear gain (no human lives at risk, no need to carry air, food, or a return trip) alongside a clear cost (robots are slower, less flexible, and cannot make quick on-the-spot human judgments), showing balanced thinking rather than a one-sided answer.