“Randall,” Venkat asked, “what’s going on with Mars’s weather? I thought you said the dust was coming back. Watney tells me the sky’s still as blue as the first Viking photos- and those were a color balance screw-up.”
“Clouds,” Randall Carter replied. He handed Venkat printouts of some satellite photos from Mars’s more distant orbiters. “Normally we get a lot of cirrus clouds- high-level clouds made of tiny water ice crystals- this time of year, when Mars is farthest from the sun. Technically the time for that was a couple months ago, but they’re back, and they’re growing.”
“What’s causing it?” Venkat asked. “Nucleation around dust particles?”
“That’s a possible cause,” Carter agreed cautiously. “But more to the point, the higher than normal temperatures in the zone between the equator and latitude 30 have probably caused a lot of water ice just under the surface to sublimate and enter the atmosphere. More water in the atmosphere means more clouds. And every time a water crystal forms in the air, it traps the dust particles it uses for nucleation points, effectively clearing the sky.” He tapped a photo of the edge of Mars’s planetary disc, clearly showing the bright blue band of its upper atmosphere. “And without the dust in the air, you're left with ordinary gas molecules and the same Rayleigh scattering effects we see on Earth. So that’s what Watney sees- blue skies.”
“All right, sounds pretty harmless,” Venkat said. “How long will it persist?”
“My guess is, roughly a month,” Carter said. “Maybe less. As Mars gets closer to the sun again, those cirrus clouds tend to sublimate again. The water vapor either gets broken up by UV rays into oxygen and hydrogen that escape the atmosphere or else gets circulated to a lower layer of air and condenses back onto the surface.” He pulled out one more bit of paper and added, “The thing is, I don’t think this trend is harmless.”
Venkat looked at the paper. “Randall, I’m a physicist, not a meteorologist,” he said. “I see these temperature and air pressure readings, but I haven’t got a background to interpret them.”
“They’re too high,” Randall said. “This is northern summer on Mars, and Mars is just beginning to swing back in towards the sun. Right now carbon dioxide should be freezing out of the air in the southern hemisphere, causing air pressure to drop. It’s not.”
“Why not?”
“Too hot. At Mars’s normal atmospheric pressure, carbon dioxide condenses at about negative 123 degrees Celsius,” Randall said. “Normal peak lows in southern winter hit or surpass minus 150. We can see it happening in seasonal photos as the ice cap expands and contracts each Martian year. The growth and shrinkage is almost all CO2. But right now temps at the poles are only dipping below the freeze point for brief periods of time, and not in a very large area. So Mars’s atmosphere is staying put.”
“Fine,” Venkat said. “But I’m not seeing how that affects Watney and the ponies.”
“I don’t see how it does either,” Randall said. “But I’m sure it will affect them. As it is, the thicker atmosphere than normal plus the cloud coverage- did I mention it’s growing? Mark will see the clouds before much longer. Anyway, water vapor is a greenhouse gas, though not in the league of CO2 or methane. The daytime heating isn’t going to dissipate as rapidly at night. Mars is about to experience the closest thing it ever gets to a heat wave.”
“How hot are we talking about?” Venkat asked.
“Double-digit positive Celsius highs at the Hab for the next two weeks at least,” Randall said. “Still about minus forty at night, but during the day the atmospheric regulator external component is going to shut down due to excessive heat. It requires super-cold temperatures to help condense components of the atmosphere-“
“Yes, I know how it works, I’m not that uninformed,” Venkat grumbled. “But the internal portion will still function, as will the oxygenator.”
“I’m not too worried about the Hab equipment,” Randall said. “I’m worried about what will be the next weather pattern after this one. This is weather we’ve never seen on Mars before, and it’s damn near global. Global temperatures twenty degrees Celsius higher than normal, day and night. That’s a lot of energy being stored up in the atmosphere. It has to go somewhere.”
“Try to figure out where,” Venkat asked.
“I already have one guess,” Randall said. “But you’re not going to like it.”
“I like it better than no guess at all. Give.”
“All right. Higher temperatures on Earth mean more giant storms- hurricanes, typhoons nor’easters, the big weather systems. They work as a means of transferring heat energy from the ground and lower atmosphere into the upper atmosphere, where it can radiate away into space. Mars doesn’t have rainfall. The closest it comes to precipitation is the occasional dry-ice snowfall at the poles. So it has only one way to do the same thing: planetary dust storms.”
“When?” Venkat asked. “This is urgent, Randall. We’re about to send six people on a perilous journey across thousands of kilometers on solar power. And for reasons of logistics, we can’t send them immediately. I need answers.”
“I’ll try to get them, Dr. Kapoor,” Randall said. “But right now we’re all guessing. We’ve got no baseline to use for predictions, not with this.”
“That’s the deal, is it?” Teddy asked.
“That’s it,” Venkat said. “I’ve thought about putting some people to work on a crash program to get the castaways on the road now, but I recommend against it.”
“Give me the pros and cons.” Teddy unconsciously straightened papers on his desk that were already perfectly aligned with the blotter.
“Okay. Pro: the sooner they roll out, the more leeway they have to make Schiaparelli by Sol 551. Up to a point the time pressure is reduced. But that’s the only pro. Con: more food would have to be packed into a vehicle that’s already critically overweight. In case of a global dust storm like, for example, the 2018 event, we’d rather have them at the Hab missing the Hermes flight than somewhere in the middle of Arabia Terra. The Hab and the cave are more durable, should the global storm include wind events like the Sol 6 storm or electrical outbursts like the Sol 247 storm.”
“So, we keep them in Acidalia if we see a dust storm forming on Sol 451?” Teddy asked.
“Not necessarily,” Venkat replied. “Remember, we knew going into this that the drive to Schiaparelli would take place at the beginning of dust storm season on Mars. There was already a minor risk of being stranded by a dust storm, but it was just that: minor. Blackout global dust storms are almost a once-a-generation thing. There are some Martian years that don’t even have a global dust storm, not even a thin one. But even so, the risks of the trip just aren’t lowered enough by an early departure to offset the logistical difficulties.”
“All right,” Teddy said. “I’ll leave this to your discretion, Venk, but please contact me if the meteorology staff comes up with anything more definitive.”
“You’ll be the seventh to know,” Venkat said solemnly.
Magic is trying to force an atmosphere, but Mars is fighting back.
Your explanation for the blue sky is incorrect. The sky is blue on Earth due to Rayleigh scattering, which is a strongly wavelength-dependent scattering of light by particles much smaller than the wavelength of the photon. CO2, H2O, and N2 would all have roughly the same effect in this regime.
So, GLOBAL dust storm, huh? With this Mars presumably having a much thicker atmosphere to match the storms in the book/movie, a global dust storm could be a huge problem.
9073507
They are a problem now, and gave Spirit hell, but when you add living beings to the mix... Red tape gets cut way faster
Hmm, I wonder if Starlight could enchant a crystal to extend Spitfire's pegasus weather senses past her suit? Let her get a "feel," of Mar's atmosphere and what it might be doing.
Mars is terraforming isnt it
OK, it's time to stop using unnecessary magic on Mars. The magic is terraforming it about 100 years too early.
9073507 Huh. So, you're essentially saying that any atmosphere composed of colorless gases would default to a blue color?
9073507 Ahem.
So why isn't the sky violet?
( obligatory XKCD )
( and more just for the giggles )
Did... Did Starlight Glimmer just accidentally terraform Mars?
9073526
Worse it is being Equestriaformed.
9073530
Pretty much. The cross-section for Rayleigh scattering goes as wavelength^-4, e.g. blue light is scattered roughly four times more strongly than red light. If you do the integral over the visible spectrum, you get the blue we normally associate with the sky. As another example, Pluto has a tenuous atmosphere of nitrogen and methane, with small organic haze particles suspended within. Since the particles are all at least a factor of ten smaller than the wavelength of visible light, Pluto has a blue sky.
nasa.gov/sites/default/files/thumbnails/image/blue_skies_on_pluto-final-2.png
Clear the dust storm by launching another engine, WCGW?
9073533
Because the Sun's blackbody spectrum peaks around 550 nm, near green, in the middle of the visible spectrum. Since the Sun emits more blue light than purple, the sky appears blue. If the Sun were replaced by a much hotter star of similar brightness, it would emit more violet light than blue, and the sky would indeed appear violet.
9073530
IIRC, assuming colourless gases, the tendency will be bluer for smaller molecules and lower atmospheric density, and whiter as either of those increase, and of course the colour temperature of the parent star plays a role.
My bet is that Mars is gearing up to smite the castaways with the Mother of all Dust Storms.
9073514
They continue trying to re-establish communication with Opportunity, but the current dust storm is still blocking too much sunlight for it to recharge. Keep your fingers crossed.
9073595
Considering that it was the mother of all dust storms that resulted in Watney being impaled and marooned in the first place (seriously, even Weir admitted that that storm was wholly unrealistic but was necessary to get the plot rolling), I'd be concerned that the great-grandmother of all dust storms is in the offing.
The one that occurs as a result of launching the MAV shall simply be known as Eve.
9073574
I kinda suspect that even if we would illuminate atmosphere with uniform spectral density light the sky still be blue and probably barely distinguishable from it's current color for non-artist guys. After all, sunlight is already relatively uniform in visible range:
upload.wikimedia.org/wikipedia/commons/e/e7/Solar_spectrum_en.svg
Although, I'm not sure about second one: for uniform spectrum there would be more blueish and more reddish
upload.wikimedia.org/wikipedia/commons/b/ba/PlanckianLocus.png
so sky may get Twilight Sparkle or Starlight Glimmer tinge
Why not take it a step further? We already know there's extremely flammable/explosive minerals around, why not a planetary dust storm that is also on fire?
Of course, I also think them Accidentallying Mars into something relatively habitable is too funny to pass up, and, while symbolically appropriate (Phoenix) I'm not sure how to make a flaming tornado help that except applying some phlebotinum.
Though I also think Mars' animosity should shine through if magically terraformed, evolving into a place humans can survive suitless... But not for very long without an excessive amount of firepower and a "local guide" to point out which plants will also eat you.
Well, it's mechacon now. If you were selling Gundam ponies then you would be golden.
Sorry to hear the con went poorly. I attended Supercon today, which had a pretty good turnout.
So the easy option, Mars knows how to make a big storm and is winding up for a hell of a punch.
Another option, it wants to melt the permafrost and kill that blasted cave farm. It won't work but it'll try: it even already got lightning inside.
Another option, it's going to use all this energy in the atmosphere for a much more direct manifestation. I'm still waiting for the Martian equivalent of Windigos.
Option 4, something even nastier we haven't seen yet. What if Mars gets it to rain? Even if it's for only a bit, can the equipment survive that?
But in any case, I'm expecting serious and directed malevolence as Mars learns and gets more power.
So the equestrian magic is beginning a terraforming process for Mars? Trying to make Mars more "harmonious"?
Randall and Martian Dust Storm...
Why does this come across as a Rocket Man reference?
Actually, I think I have read the exact opposite once. Are you sure water is less of a greenhouse gas compared to CO2?
9073641
The last great grandmother of a storm I read about destroyed a spaceship, and changed the entire power structure of the galaxy. Poor Shaddam the fourth...
9073831 C'mon, the guy was a douchenozzle. He thouroughly deserved to be kapowed and kersplatted.
So is this because of the launch crystal test, or because the six of them are on Mars generally, or just coincidence? And what was the 2018 thing?
You aren't the only one wishing they were at Bronycon, though your reasons are a lot more selfless than mine
Did we decide on a name for the cave farm yet? If not, we vote for Cave Harmony!
My bet is on massive electric storm that fries Pathfinder.
Are you sure "Mars's" is correct?
I was surprised to see a book-exclusive character in Randall Carter. I wonder what he looks like?
Aha! The 2018 storm, yes! Speaking of current events, did you hear that they found an underground lake on Mars recently? And that Mars is really close to the moon right now in our sky, one day after the eastern hemisphere's lunar eclipse?
Equestrian magic: Huh, this place is really bad at supporting life. Let's see what we can do to make the temperature range a little more bearable.
Mars: Do. Not. Want!
Equestrian magic: Just give it a try. You might like it.
Mars: if you make me warmer, I'm going to manifest storms like you wouldn't believe.
Equestrian magic: That's not very friendly. Hmm... not enough power for anything big... Oh, there are cherry trees and magic crystals over there and the ponies and the monkey-thing are planning another event. Mars, how would you like a proper oxygen atmosphere?
Mars: Die!
Wasn't the "Mk. 1" eye just a patch of slightly light-sensitive skin? The Mk.2 was a concave dish of improved sensor-skin, and so forth — until the modern eyeball, which would perhaps be the Mk. 6 at a conservative estimate.
Frankly, I wouldn't trust the human eyeball with correctly analysing the colour of anything. After all, it only has sensors for three separate wavelengths (Red, Green, Blue) and all the other colours we think we see are just interpolations, based on the differential stimulation of those three types. That's why, when you see something "yellow" on an RGB screen, you are not actually receiving real, yellow light — you're just having your receptors stimulated by proportionally scaled red and green light waves, to create the perception of yellow light in your brain. Similar things are true for the CMYK printing process. An alien with more or just differently tuned receptors (e.g. Infrared, Yellow, Cyan) would see everything on our monitors and anything printed as completely colour-distorted and nothing like the real thing.
And that's entirely apart from the contextual colour "correction" that the brain performs, so that we "see" an object as being what our brain estimates should be its real coloration, even when the prevailing lighting conditions mean that our actual eyeballs receive completely different signals. White&Gold vs. Blue&Black, anyone?
9073899
9073819
Well, it depends on what you want to measure, total heating per gas, or relative heating per gas:
H2O does around 70% of heating on Earth, but has a PPM value of 10K-50K in the Atmosphere on average.
CO2 does 15% of the heating with just 400 PPM (and increasing.)
Methane (CH4) does around 5% of the Heating with only 1,8 PPM (and increasing.)
Ozone (O3) does 4% of the heating with an average PPM of 4.
The rest done by other gases.
So H2O has low heating per PPM, but it has a very large amount in the atmosphere, so it still does the most for heating up Earth to the current level. (And the total heating is around 30 degree)
Huh, when you accidently terraform a planet by blasting exotic energy all over the place. And then mars retaliates by forcing them to miss the Hermes rendezvous. We may actually end up waiting for the equestrians. Y'know, that stump would make a perfect locus for a mirror-portal if they could get a lock on the planet, and figure out the spell.
Given the ice cliffs that were photod a few weeks back were 200 foot thick? How quickly will those faces boil off backwards, destabilising the overlaying mateial, having it crash down, exposing intermediate ice forms and throwing dust up, allowingthe heat to penetrate further back, causing cliffs to slump. Enough to trigger the autocatalysing atmospheric dump and thermal runaway that I cant remember the name of the story of where some buisinessman bought up all the CFCs and dumb launchers to drop thousands of tons of stuff on Mars?
At the rate Mars is going to be undergoing Permafrost Crustal Inversion, someones going to have to seriously consider Project Lonestar. Strap in everyone, we're going to go to Hypeperactive.
Starlight infected Mars and planet is having fever.
9073875
you are not following NASA news, aren't you. Since early June planet was enveloped in massive global dust storm, they lost contact with Opportunity because it starved
9073904 "Mk. 1 Eyeball" is 20th Century milspeak for "direct visual contact" as opposed to using viewfinders, radar, binoculars, etc. It's not a biological term.
9073979 Not to mention that water vapor clouds actually mitigate atmospheric heating by reflecting infrared (heat) energy back into space. (They also help trap heat in the lower levels of the atmosphere, so their net effect is a little towards warming, but CO2 just grabs that heat and hugs it tight and names it George and hugs and squeezes and pats and pets...)
9074107
I know. I was just running with the metaphor, for the purpose of showing off how edjumacated I am — Uh, I mean, to provide some interesting and stimulating factoids! Yeah, that's definitely the reason, and not the other thing I said out loud. Except in writing.
Gottagobyyyeee!
I blame Starlight.
I dunno Kris, I saw some weird tweets from Bronycon's dealer room that sounds like an angry Mars was affecting reality. Water was leaking in forcing everyone to get off the floor or have your stuff get swamped, then a later tweet claimed lightning in the room struck. Pretty sure the lightning was just a really big static discharge and/or bad wiring in the ceiling. As for a reenactment of The Titanic, heh, local flooding?
The other popular tweet is plushie makers complaining about a few cash-strapped fans asking how much they can get with $50 when the going rate is around $400. It's a similar grief with artists and fans asking for free commissions.
Glad you mentioned the current storm. I dug my scope out to peek at Mars last night since it's in opposition, and it was a tad unsettling to see the entire planet a featureless blob.
9073731
Carnivorous potato plants will be the result of them preserving the cave farm.
9074316
Did someone mention a Vegetable Assault?
66.media.tumblr.com/59665fac756a3b521551eba5e930b870/tumblr_o43qvpcHTX1r51we7o1_500.gif
Potentially global dust storms? A weather manipulating pegasus and lots of mana batteries. Coincidence? Spitfire, this could be your moment to shine. First sonic rainboom on Mars?
9074081 Nope, I saw the discovery of the lake, but the dust storm is new to me. Do they think Opportunity is savable?
9074469
Yeah, it just went into low power mode. Once the storm clears and it can get sunlight it should be fine. There is some concern that it might not have the ability to keep warm enough, but that's about it. Curiosity is still going strong though, since it's got an RTG instead of solar panels.
9074684 That is happy I saw the recent picture of Curiosity in the storm, I hadn’t realised it was due to the different power source, though.
Did you know Curiosity sings?
9073988
Huh, good point.
And we know it can be subject to lightning strikes. LIGHTNING POWERED SIGNAL PORTAL!
"With all due respect, your harmoniousness, couldn't we just wait for a real storm?"
"Save your breath Mark! Faster!"