Why is Callisto calmer for spacecraft?

It orbits outside Jupiter's harshest radiation

Callisto Quiz: Jupiter's Ancient, Heavily Cratered Moon

This Callisto quiz explores Jupiter's quiet, battered moon. Play 10 interactive questions on its ancient, crater-covered surface, the huge multi-ring Valhalla basin, little geological activity, its size rank among moons, a possible ocean deep below, its position outside Jupiter's harshest radiation, a NASA study of a future human base and its discovery by Galileo.

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🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Planet
Which planet does Callisto orbit?
Surface
What is Callisto's surface known for?
Valhalla
What is Valhalla on Callisto?
Active
How geologically active is Callisto?
Rank
How does Callisto rank in size among Solar System moons?
Ocean
What might lie deep beneath Callisto's surface?
Radiation
Why is Callisto calmer for spacecraft?
Base
What did a NASA study consider for Callisto?
Found
Who discovered Callisto?
Name
Who was Callisto in Greek myth?

Explanations: answer key for all 10 questions

Q1: Which planet does Callisto orbit?
Answer: Jupiter
It is a Galilean moon.
Q2: What is Callisto's surface known for?
Answer: Being covered in craters
It is ancient.
Q3: What is Valhalla on Callisto?
Answer: A giant multi-ring impact basin
Rings ripple outward.
Q4: How geologically active is Callisto?
Answer: Very little
Its surface has changed little.
Q5: How does Callisto rank in size among Solar System moons?
Answer: Third largest
Ganymede and Titan are bigger.
Q6: What might lie deep beneath Callisto's surface?
Answer: A salty ocean
Magnetic data hint at it.
Q7: Why is Callisto calmer for spacecraft?
Answer: It orbits outside Jupiter's harshest radiation
Inner moons get more radiation.
Q8: What did a NASA study consider for Callisto?
Answer: A possible future human base
Low radiation made it attractive.
Q9: Who discovered Callisto?
Answer: Galileo
He found it in 1610.
Q10: Who was Callisto in Greek myth?
Answer: A nymph loved by Zeus
Jupiter's moons are named after his loves.

An Ancient, Battered Moon

Callisto is one of Jupiter's four large Galilean moons, discovered by Galileo in 1610. It is the third largest moon in the Solar System, after Ganymede and Titan. Its surface is covered in craters, making it one of the oldest surfaces known.

Callisto shows very little geological activity, so its craters have built up over billions of years. Valhalla, a giant multi-ring impact basin, has rings rippling outward from the point of impact. Magnetic measurements hint that a salty ocean may lie deep beneath the surface.

Callisto orbits outside Jupiter's harshest radiation belts, so a NASA study once considered it a possible site for a future human base. In Greek myth, Callisto was a nymph loved by Zeus. ESA's JUICE mission will study Callisto in the 2030s.

What This Quiz Teaches

Space fans will enjoy these questions.

What Callisto is
What its surface looks like
How active it is
What may lie beneath
Why it suits a base

Did You Know?

Callisto is dark with bright crater rims.
It takes about 17 days to orbit Jupiter.
It is tidally locked to Jupiter.
Galileo the spacecraft flew past it.
Its surface mixes ice and rock.