Madeline looked at Helen. "Maybe it's a male thing. You know, driving toward certain death? Like their idiot ancestors used to charge into battle naked, to show they weren't afraid."
That caused A.J., who had been about to say something, to laugh again. "Sorry, sorry, but—look, we're on Mars. The air pressure out there is less than a fiftieth of Earth's. That's how dense—or thin, rather—it is compared to our atmosphere. And it's how dense a fluid material is that really determines how hard it's going to hit you. Look at water: if you immerse yourself in water and even weigh yourself down with lead, just try standing against a current of a few kilometers an hour."
"Oh." Madeline felt foolish. She had a vague memory of reading something about this in one of the dozens of books and papers she'd studied during their training for the mission.
Helen stared out the port. "So what you're saying is that you could walk right out there into that thing and it'd feel like being in . . . "
Joe did the calculations for her. "About a sixteen kilometer per hour wind back home. A nice breeze, and that's about it. With a bunch of dust."
"So it's no threat?"
"None at all, not to Thoat. In fact, we should have all our sensors going as we drive through it. Might learn something. Though I'd slow down a bit in the fog."
"Don't need to teach me my business, mate. I don't drive faster when I can see less, rest assured."
Madeline still felt an involuntary tension as the swirling vortex approached. Towering as high as the canyon walls and spinning at over a hundred miles per hour, it did not seem harmless at all but a looming, elemental threat.
Then Thoat was plunging into the maelstrom. She thought she felt a faint vibration, and there was a slight hissing noise. But aside from the sight of the dirty yellowish haze streaming by and obscuring their normal vision, the huge rover simply ignored the formidable-looking dust devil.
A faint, almost subliminal flicker made her jump. "What's that?"
Bruce and A.J. leaned forward. "Hey! That's cool." Deep purplish light shimmered, barely at the level of visibility, on the few sharper edges on Thoat's nose. The violet light brightened and seemed to leap from one of the short sensor antennas toward the ground several times.
"Cool, fine, but what is it, and is it dangerous?" Madeline was a bit nettled by the uninformative reaction. Her instinct was that anything you didn't understand could be dangerous, so you needed to understand it fast.
"Corona discharge," Joe answered. "Mars' atmosphere is almost as thin as the pressure inside a neon light tube. Close enough that if you build up electrical charges, they'll jump long distances. It's not dangerous to us, though. The rover's insulated, and when you go through the lock those handgrips you're required to hold make sure that if you did build up a charge outside, it gets equalized. But it could be a pain in other ways. Also might give us some other phenomena to see later."
Momentarily they broke back into sunlight, looking up at a slice of bright pinkish sky surrounded by the spinning sand clouds. Madeline was not the only one to exhale in relief.
Somewhere in the middle of that, without her remembering having done so, she discovered that her hand was holding Joe's. It was the first time there'd ever been any physical contact between them in public. Even in private, there hadn't been much, since their reconciliation. For reasons that were still obscure to her, Madeline had not been willing to move quickly, in that regard.
Fortunately, Joe hadn't pushed the issue. Madeline wasn't sure why, since it certainly wasn't a lack of sexual attraction. As the days had passed and she'd gotten to know him better, she'd decided that the explanation was very simple. Joe was smart enough to know that he wasn't smart about things like that, so he was willing to let her take the lead and set the pace.
She felt very warm, for a moment, and gave Joe's hand a squeeze.
Then they reentered the storm.
"It sure looks impressive," A.J. said. "But it's just a bunch of hot air."
Helen slapped him playfully.
"Sorry, I didn't mean to shock you. I was just trying to make a comment about current events."
"Okay, that's enough," Joe said sternly. "Give him his discharge."
Madeline snatched her hand away. "God help us! Helen, we're doomed. Months of this, we're facing! Their jokes were bad enough, but now—puns, too?" She almost wailed the last two words.
Helen shook her head gloomily. "I know. We'll just have to breeze through it."
Ignoring the aghast look on Madeline's face, the paleontologist leaned forward and asked Bruce: "How far have we got to go?"