As far as we know, there are no Martians living on Mars. But we do have a friend there who calls us. In 2003 two robots named Spirit and Opportunity flew by rocket to Mars, where Opportunity landed exactly 13 years ago today! (Spirit was 3 weeks ahead.) They bounced out of the spaceship wrapped in poofy balloons, rolled to a stop, then turned on their cameras and started puttering around. They’ve been sending photos and chemistry test results to Earth ever since. The rovers were supposed to last only about 90 days, but they’ve surprised us: Spirit drove until falling into a sand trap in 2010, and Opportunity is still roving, a whole 13 years later!
Wee ones: Were you alive 13 years ago? How old are you by comparison?
Little kids: If Spirit and Opportunity each have 4 wheels, how many wheels do they have together? Bonus: If Opportunity landed in 2004, in what year did Opportunity celebrate 10 years on Mars?
Big kids: The rovers took off in July 2003 and landed in January 2004. About how many months did their trip take? Bonus: In 2003 Earth was as close to Mars as possible — 35 million miles. Meanwhile, Earth is always about 93 million miles from the Sun. What’s the farthest apart Earth and Mars can be? (You can ignore the width of the Sun.)
Wee ones: Different for everyone…talk about your birth year, your age, etc.!
Little kids: 8 wheels. Bonus: In 2014.
Big kids: About 6 months. Bonus: 221 million miles. They’ll be farthest apart when Earth is on the other side of the Sun, which adds 2 times its distance from the Sun, or 186 million miles. Then Mars is another 35 million miles beyond that.