They can tell you it is true, and it is, but it is a really hard concept to grasp. We live on a giant sphere that is circling through the vacuum of space around the sun. The people on the other side of this sphere are upside down to us but they manage. They walk around. We walk around. All of us are, feet first, on the earth, being pulled by gravity.
Circling around the Earth is the moon. We’ve been there. With rocket ships, it is not that far away. Also, as it happens, it seems to have once been a part of the Earth that later got ripped off, fashioned into a ball and caused to circle around the Earth, so it comes as no real surprise that the dirt on the moon is similar to the dirt from the Earth.
Aware when I was growing up about all this, I also knew that because absolutely everything else was so far away, it was very unlikely that I would ever get off the Earth. But here on Earth there was a lot to see. So I made it a priority to visit as many parts of it as I could over the years just to see what was what. I’ve been on the underside. I’ve been to the southern tip of Africa. I’ve been to Japan, to the Caribbean. The cultures are pretty different everywhere, but in many ways we all have a lot in common.
I mention all this because when all is said and done, I didn’t think too much about it when we lowered the rover Curiosity down onto the planet Mars. My frame of reference says that Mars might as well be a distant star. It’s something that can be appreciated from afar, even marveled at. It also seemed very likely to me that since it took nearly eight months for our rover to get to Mars, Mars might be very different from our Earth and moon in composition. It could also be true that Mars supports other and more interesting life forms. We’ve all seen the science fiction movies. Who knows what goes on in a place that was born and raised totally separate from the Earth for not just billions but trillions of years from a time when both these planets and six more were thrown off from our sun?
Then on the radio the other morning, I heard a man from the Jet Propulsion Laboratory in California, which built Curiosity and manages the mission, describe how Curiosity analyzes the dirt it scoops up and, of particular interest, how it gets rid of it by opening a hatch on the bottom so the dirt can drop out.
“How does Curiosity clean his insides so when the next scoop is brought in, the material does not get mixed in with the residue of what was in there before?” the interviewer asked. “Surely there is something of the old left over.”
Curiosity can shiver, the official said. He shivers and shakes for quite some time. All the loose particles then come off his insides and out the bottom.
The interviewer said this reminded him of how you clean a frying pan when you are out camping. You rub dirt on it, shake it, wipe it, then hit the frying pan on a rock to get everything off.
What was even more interesting were the results of the analysis. The dirt so far scooped up is very similar to the dirt you find here on Earth in places where there has been relatively recent volcanic activity. It’s very similar to what’s on the Mauna Kea volcano in Hawaii. It’s not that different at all. How extraordinary!
Of course, this is only one part of this place. Mars is not so much smaller than Earth, so there is a lot more of it to explore, just as there would be a lot more to explore the first time that something from afar touched down on Earth. On Mars, there are mountains, former riverbeds, cliffs, dry lake beds. We’ve seen them, having peered down from orbiters with cameras circling around Mars for a few decades. And Curiosity is moving, slowly, to explore as much as he can. The point where Curiosity was set down (lowered by cables from a hovering spacecraft) is a place where the ground isn’t level but isn’t very steep, either. It was chosen because it is not far, just 1,300 feet, from a place where different kinds of Mars landscapes come together. From where it came down, Curiosity is going to that place.
Curiosity moves very slowly—less than a tenth of a mile an hour—on zigzag tire treads. We can control him from Earth. Using a computer keyboard, we can get him to turn, then move forward, then stop. Curiosity’s camera is linked to a computer. But then we have a second computer mounted on a stalk. Scientists on earth see with the one on board. If one camera thinks it’s okay to go and the other doesn’t, the scientists look at the two cameras to see why. Then they might try sending him off somewhere else.
I want you to consider this from a Martian’s point of view. This thing is a mass of wires, frame, aluminum and titanium, and has an arm sticking up with a gripper on the end which not only has the ability to see but also can drill, grasp and put stuff into its maw. It can also drop off what it scooped when it’s done with it. It resembles a giant scorpion stinger.
Curiosity has all sorts of other things that it uses on Mars. It has a laser beam it can fire at rocks to break them up from as far away as 23 feet. It has a hammering drill; it has the aforementioned scoop, a telescope, numerous cameras, sensors to measure pressure changes, wind speeds, radiation and humidity. And of course it is nuclear powered. It can run around by itself for years, unless an angry Martian comes along and wrecks it, which it could because other than the laser and drill, Curiosity can’t defend itself and can’t even explain what it is doing there.
As for me, my wife and I are considering a vacation for the month of January. New Zealand? Been there. Mexico? Been there. South America? Been there. Paris? London? Moscow? Cape Town? Been there, been there, been there, been there. What haven’t we seen?
Dammit, there’s Mars.