Major Funding The Laura Moore Cunningham Foundation

Mars: Top 10 Questions

September 2013

Thanks to Todd Barber, Lead Propulsion Engineer, Cassini Mission, Jet Propulsion Laboratory; and Matthew Heverly, Mobility Systems Engineer, Jet Propulsion Laboratory for the answers.

1: How big is Mars?

Mars is about half the diameter of Earth. Earth's diameter is roughly 8,000 miles and its circumference is 25,000, so Mars would be about 4,000 miles in diameter. (From Josue at Cynthia Mann Elementary in Boise)

2: Why is Mars hot when it is far from the sun?

Mars isn't that hot. It is pretty cold during the daytime and the nighttime. We have a weather station on the rover that sends us a weather report every day. Three hundred fifty seven Mars-days after landing, the high was negative 7 degrees Celsius and the low was negative 76 degrees Celsius (that's 19 and minus 104 degrees Fahrenheit). It's actually really, really cold on Mars and it's challenging for us to design a rover that can survive the cold Martian nights! (From Ellie at Owyhee Harbor Elementary School in Boise)

3: What causes Mars to be sphere shaped?

It's essentially the force of gravity and that's why all of the large planets are basically like a sphere. Nature tries to minimize energy. It wants the minimum surface area for a given volume, and that's a sphere. (From Cholle at Owyhee Harbor Elementary School in Boise)

4: If water were on Mars, could you live on it?

Mars did have water that we could drink. From our discoveries, the water looked to be really acidic, but the water that Curiosity found looked to be like that found in streams and rivers here on Earth. Because it's no longer there, there's no longer any water on the surface of Mars. As was said earlier, Mars is no longer habitable because of the extremely cold temperatures. (From Bradan at Cynthia Mann Elementary School in Boise)

5: How hot can Mars get?

Even though Mars is generally a very cold planet, it can have pleasant temperatures. Four conditions must be met: If Mars is as close as it can get to the sun in its elliptical orbit, if it's about noon, if it's the middle of summer, and finally, if you are on its equator. When those 4 conditions are met, it can get to 75 or 80 degrees Fahrenheit. (From Ike at Cynthia Mann Elementary School in Boise)

6: How many volcanoes are on Mars?

We're still trying to map out all of the geological features on Mars, but what we know is that there used to be a lot of volcanoes. Now, however, there are no active volcanoes on Mars. There used to be active volcanoes spewing lava all over the surface of Mars, but not anymore. All those have gone extinct. (From Junior at Cynthia Mann Elementary School in Boise)

7: How many moons does Mars have?

Mars only has two moons, one more than we have around Earth. The names of the moons are the Greek words for fear [Phobos] and panic [Deimos], and we believe they are probably captured asteroids. (From Claire at Cynthia Mann Elementary School in Boise)

8: Does Mars have water?

With our rover missions, we have found past evidence of water. We have found evidence that there used to be flowing streams and rivers on the surface of Mars. Ice has even been found under the surface. However, we know that water cannot exist on the surface with the conditions that exist today. (From Connor at Owyhee Harbor Elementary School in Boise)

9: Was there life on Mars?

We don't know yet. Billions of years ago, Mars was warmer and wetter. We have a lot of evidence that liquid water was on the surface. On Earth, whenever we find water, a source of heat molecules and some organic molecules, life is abundant. Mars seems to be a pretty inviting place, at least billions of years ago, for biology to take hold. We do the rover missions for that very question. (From Dalton at Owyhee Harbor Elementary School in Boise)

10: Is Mars red because the rocks are made of iron oxide?

Yes, Mars is red because of iron oxide. It's like good old rust here on Earth. When you have metal in an oxidizing environment, it tends to form the oxides that have the reddish/rust color. (From Kyia at Dalton Elementary School in Dalton Gardens)

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