Red Velvet with Icing

“So Jupiter’s white stripes are huge updrafts of ammonia snow and its dark stripes are weird chemicals we only see when downdrafted ammonia snow evaporates. Fine, but how does that account for my buddy the Great Red Spot? Have another lemon scone.”

“Thanks, Al, don’t mind if I do. Well, those ideas only sort-of account for Spot. The bad news is that they may not have to for much longer.”

“Huh? Why not?”

“Because it seems to be going away.”

“Hey, Sy, don’t mess with me. You know it’s been there for 400 years, why should it go away now?”

“I don’t know anything of the kind. Sure, the early telescope users saw a spot 350 years ago but there’s reason to think that it wasn’t in the same location as your buddy. Then there was a century-long gap when no-one recorded seeing anything special on Jupiter. Without good evidence either way, I think it’s entirely possible we’ve had two different spots. Anyway, the new one has been shrinking for the past 150 years.”

“The big hole must be filling in, then.”

“What hole?”

Juno GRS image, NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt

“The Spot. If the dark-colored stripes are what we see when the bright ammonia ice evaporates, then the Spot’s gotta be a hole.”

“A reasonable conclusion from what we’ve said so far, but the Juno orbiter has given us more information. The Spot actually reaches 500 miles further up than the surrounding cloud tops.”

“But higher-up means colder, right? How come we don’t see the white snow?”

“That higher-is-colder rule does apply within Jupiter’s weather layer, mostly, but the Spot’s different. There seems to be a LOT of heat pouring straight up out of it, enough to warm the overlying atmosphere by several hundred degrees compared to the planetary average. That suppresses the ammonia ice, lifts whatever makes the red color and may even promote chemical reactions to make more.”

“But Sy, even I know heat spreads out. You’ve just described something that acts like a searchlight. How could it work like that?”

“Here’s one hypothesis. You’ve got your sound system here rigged up so the back of the shop is quiet, right? How’d you do that?”

“Oh, I bought a couple of directional speakers. They’re deeper than the regular kind and they’ve got this parabolic shape. I aimed them up here to the front where the traffic is. Work pretty good, don’t they?”

“Yes, indeed, and I’m grateful for that. See, they focus sound energy just like you can focus light. Now, to us the Spot just looks like an oval. But it’s probably the big end of a deep cone, spinning like mad and turning turbulent wind energy into white noise that’s focused out like one of your speakers. Wouldn’t that do the trick?”

“Like a huge trombone. Yeah, I suppose, but what keeps the cone cone-shaped?”

“The same thing that keeps it spinning — it’s trapped between two currents that are zipping along in opposite directions. The Spot’s northern boundary is the fastest westbound windstream on the planet. Its southern boundary is an eastbound windstream. The Spot’s trapped between two bands screaming past each other at the speed of sound.”

“Wow. Sounds violent.”

“Incredibly violent, much more than Earth hurricanes. At a hurricane’s eye-wall the wind speeds generally peak below 200 miles per hour. The Great Red Spot’s outermost winds that we can see are 50 miles per hour faster but those triangular regions just east and west must be far worse. When I think about adding in the updrafts and downdrafts I just shudder.”

“Does that have anything to do with the shrinking you told me about?”

“Almost certainly — we simply don’t have enough data to tell. But the new news is that your buddy’s uncorked a fresh shrinkage mode. Since the mid-1800s it’s been contracting along the east-west line, getting more circular. Now it seems to be flaking, too. Big, continent-size regions break away and mix into the dark belt above it. Meanwhile, the white equatorial zone is getting darker, sort of a yellow-green-orange mix.”

GRS image courtesy of Sharin Ahmad

“Yucky-colored. Does that mean the Spot’s draining into it?”

“Who knows? We certainly don’t. Only time will tell.”

~~ Rich Olcott

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Icing on The Brownie

“So what you’re saying, Sy, is that Jupiter’s white stripes are ammonia snow clouds that go way up above a lower layer of brown clouds like the white icing stripes I put on my brownies.”

“That’s what I’m saying, Al.”

“But why stripes? We got white clouds here on Earth and sometimes they’re in layers but they don’t make stripes.”

“Well, actually they do, but you need the long-term picture to see it. Ever notice that Earth’s forests and deserts make stripes?”

“How ’bout that? I guess they do, sorta. How’s that work?”

“It took us five hundred years to figure out the details. Quick summary. Sunlight does its best year-round heating job at the Equator, where the oceans humidify the air. Warm air rises. Rising warm air cools, releases its moisture as rain, and you get a rainforest belt. The cooled, dried air spreads out until it sinks at about the 30th parallels north and south. Dry air sucks moisture out of the land as it returns to the Equator and you get desert belts. Repeat the cycle. More loops like that center around both 60th parallels. The pattern’s not completely uniform because of things like mountain ranges that block some of the flows. Basically, though, as the years accumulate you get stripes.”

“Jupiter does that, too, huh?”

“On steroids. In one way it’s simpler — no underlying continents mess things up. On the other hand, Jupiter’s got more than a hundred times Earth’s surface area so there’s room for more loops. Also, Jupiter’s interior is still shedding a lot of heat, almost as much as the planet gets from the Sun. Here’s a diagram on Old Reliable.”

“So you’re saying that the upward loops push Jupiter’s atmosphere to where it’s colder and those white ammonia snow clouds form. Then the downward loops move the clouds to where it’s warmer and the ammonia evaporates to show us the brown stuff. Makes sense. But what’re those side-to-side arrows about? We got anything like those on Earth?”

“Sort of, a little bit. Remember the Coriolis force?”

“Uhh, that’s what makes hurricanes go round and round, right? Something to do with the Equator running faster than places further north or south?”

“That’s the start of it. The Earth as a whole rotates 360° eastward in 24 hours, but how many miles per hour that is depends on where you are. The Equator’s about 25000 miles long so Quito, Ecuador on the Equator does a bit more than 1000 miles per hour. Forty-five degrees away, the 45th parallels are only 70% as long as that, so Salem, Oregon and Queenstown, New Zealand circle 70% slower in miles per hour. Suppose a balloon from Salem travels south as seen from space. As seen from the Equator, the balloon appears in the northeast rather than straight north. Winds work the way that balloon would. All around the world, winds between 10° and 30° north and south come from an east-ish direction most of the time.”

“What about the winds right at the Equator? You’d think the northerly part and the southerly part would cancel each other out.”

“That’s exactly what happens, Al. We’ve got a more-or-less equatorial belt of thunderstorms from humid air cooling off as it goes straight up, but not much of a prevailing wind in any direction — that’s why the old sea captains called the region ‘the doldrums’.”

“An equator belt like Jupiter’s, eh?”

“Not quite. Jupiter has a lovely white equatorial zone all right, but that one doesn’t stand still. It roars eastward, 300 miles per hour faster than the equator’s own 28000 miles per hour. All Jupiter’s white zones move east at a pretty good clip. Its dark belts sprint westward at their own hundred-mile pace. Then there’s the jet streams that run between neighboring bands, and lots of big and little vortices carried along for the ride. The planet’s way too segmented and violent for Coriolis forces to build up enough to play a part. The scientists have a couple of heavily-simplified models, but nowhere near enough data or computer time to fill them in.”

“Earth’s atmosphere is messy enough, thanks. My brain’s hurting.”

Voyager I video of Jupiter, processed by JPL,
from Wikimedia Commons

~~ Rich Olcott

Lemon, Vanilla, Cinnamon

Al claims that lemon’s a Summertime flavor, which is why his coffee shop’s Scone Flavor of the Month in July is lemon even though it doesn’t go well with his coffee. “Give me one of those lemon scones, Al, and an iced tea. It’s a little warm out there this morning.”

“Sure thing, Sy. Say, what’s the latest science-y thing up in the sky?”

“Oh, there’s a bunch, Al. The Japanese Hayabusa-2 spacecraft collected another sample from asteroid Ryugu. NASA’s gravity-sniffer GRAIL lunar orbiter found evidence for a huge hunk of metallic material five times larger than the Big Island of Hawai’i buried deep under the Moon’s South Pole-Aitken Basin. The Insight Mars lander’s seismometer heard its first Marsquake —“

“Quit yanking my chain, Sy. Anything about Jupiter?”

“Gotcha, Al. I know Jupiter’s your favorite planet. As it happens I do have some Jupiter news for you.”

“The Juno orbiter’s still working, I hope.”

“Sure, sure, far as I know. It’s about to make its 13th close flyby of Jupiter, and NASA administrators have green-lighted the mission to continue until July 2021. Lots of data for the researchers to work on for years. Here’s a clue — what’re the top three things that everyone knows about Jupiter?”

“It’s the biggest planet, of course, and it’s got those stripes and the Great Red Spot. Has the planet gotten smaller somehow?”

“No, but the stripes and the Red Spot are acting weird. Had you heard about that?”

“No, just that the Spot’s huge and red and been there for 400 years.”

“Mmm, we’re not sure about the 400 years. But yes, it’s huge.”

“Four times wider than Earth, right?”

“Hasn’t been that big for a long time. Back in the 1870s telescope technology gave the astronomers that ‘four Earths wide‘ estimate. But the Spot’s shrunk in the last 150 years.”

“A whole lot?”

“Last measurement I saw, it’s just barely over one Earth wide. Seems to have gotten a bit taller, though, and maybe deeper.”

“Taller and deeper? Huh, that’s a new one. I always thought of the Spot as just this big oval ring on Jupiter’s surface.”

“Everyone has that bogus idea of Jupiter as a big smooth sphere with stripes and ovals and swirls painted on it. Don’t forget, we’re looking down at cloud tops, like those satellite pictures we get looking down at a storm system on Earth. From space, one of our hurricanes looks like a spirally disk centered on a dark spot. That dark spot isn’t in the clouds, it’s actually the top of the ocean, miles below the clouds. If you were a Martian working with photos from a telescope on Phobos, you’d be hard-put to figure that out. You need 3-D perspective to get planets right.”

Jupiter image courtesy ESA/Hubble

“Those stripes and stuff aren’t Jupiter’s surface?”

“As far as we can tell, Jupiter doesn’t have a surface. The hydrogen-helium atmosphere just gets denser and denser until it acts like a liquid. There’s a lot of pressure down there. Juno recently gave us evidence for a core that’s a fuzzy mix of stony material and maybe-metallic maybe-solid hydrogen but if that mush is real it’s only 3% of the planet’s mass. Whatever, it’s thousands of miles below what we see. Jupiter’s anything but smooth.”

“Lumps and bumps like this bubbly scone, huh?”

“More organized than that, more like corduroy or a coiled garden hose. The white stripes are hundreds of miles higher-up than the brown stripes so north-to-south it’s like a series of extreme mountain ranges and valleys. The Great Red Spot reaches up maybe 500 miles further.”

“Does that have to do with what they’re made of?”

“It has everything to do with that, we think. You know Earth’s atmosphere has layers, right?”

“Yeah, the stratosphere’s on top, then you got the weather layer where the clouds are.”

“Close enough. Jupiter has all that and more. Thanks to the Galileo probe we know that Jupiter’s ‘weather layer’ has a topmost blue-white cloud layer of ammonia ice particles, a middle red-to-brown layer containing compounds of ammonia and sulfur, and a bottommost white-ish layer of water clouds. The colors we see depend on which layer is exposed where.”

“But why’re they stripey?”

~~ Rich Olcott

Why So Big?

“How come so big, kid?”

“Beg pardon, Mr Feder?”

“Mars has the biggest volcanoes and all, like that canyon you can’t even see across.  Earth’s bigger than Mars, right?  How come we don’t have stuff like that?”

“Maybe we do but we’ve not found it yet.  Earth’s land area is only 4% greater than the surface area of Mars.  Our ocean floor and what’s beneath the Greenland and Antarctic ice sheets are like a whole second planet twice as big as the land we’ve explored so far.  Some people refer to the Mid-Atlantic Ridge as a 10000-mile-long volcano.  No-one knows for sure what-all else is down there.  Even on land we’ve probably had enormous landforms like Alba Mons but on the geologic timescale they don’t last long here.”

“So like I said, how come?”

“Because of what we have that Mars doesn’t.  Massive forces of erosion — wind, water, Goldilocks temperatures — that grind down landforms something fierce.”

Watney_s route 420
Mark Watney’s travel route in The Martian.
Image by ESA/DLR/FU Berlin
under Creative Commons license

“Wait, Mars has winds.  What about those dust storms, and that windstorm that damn near destroyed Watney’s spaceship?”

“Um, Watney’s a fictional character.  The dust storms do exist, though —  one of them created a blackout that may have killed the Opportunity rover’s solar power.  But Martian dust grains are about the size of smoke particles.  Doesn’t take much of a wind to get those grains into the air and keep them there even in Martian atmosphere that’s only 1% as thick as Earth’s.  A 120-mph wind on Earth would blow you over, but one on Mars would just give you a gentle push.  Martian winds can barely roll a sand grain along the ground.  They definitely can’t sandblast a volcano like Earth winds can.  Which, by the way is why planetologists panned that storm scene in your The Martian movie.  Couldn’t happen.  The film production team admitted that.  The rest of the science was pretty good, though.”

“OK then, water.  You talking like dripping water can wear a hole in a rock?”

“More like water in quantity — glaciers carving off mountaintops and rivers digging canyons and ocean waves smashing shorelines to sandy powder.  Dripping water works, too — water’s corrosive enough even at low temperatures that it can dissolve most kinds of rock if you give it enough time.  But Mars has no glaciers or rivers or oceans.  Probably no dripping water, either”

“You were kidding about Goldilocks, right?  Talk about fictional characters!”

“Not in this case.  To planetologists, ‘Goldilocks’ is a technical term.  You know, ‘not too cold, not too warm…”

“‘Just right,’ yeah, yeah.  But just right for what?  What’s Mars got that’s Goldilocks-ish?”

“Sorry, it’s Earth that has the Goldilocks magic, not Mars, and what’s just right is that we’re in the right temperature range for water to exist in gas and liquid and solid forms.  Mars’ surface is way too cold for liquid water.”

“Wait, I read that they’d found liquid water there.”

“Not on the surface.  The radar experiment aboard European Space Agency’s Mars Express spacecraft found an indication of liquid water, but it’s a kilometer below the surface.  Twenty kilometers wide, maybe a meter thick — more of a pond than the ‘lake’ the media were talking about.”

“Why should it make a difference that Earth’s Goldilocks-ish?  I mean, we’re comfortable but we’re not rocks.  What’s that got to do with the volcanoes?”

“Recycling, Mr Feder, recycling.  On Mars, if enough gaseous water molecules could get together to make rain, which they can’t, they’d freeze to the ground and stay there for a long, long time.  On Earth, though, most rain stays liquid and you get ground water or run-off which eventually evaporates and rains down again.  The same molecules get many, many chances to grind down a mountain.”

“But Earth water can freeze, too.”

“Remember we’re Goldilocks-ish.  Liquid water soaks into a cracked rock where it freezes, expands to pry off a chip or two, and thaws to freeze again.  Water’s freeze-thaw cycle can do a lot of damage if it gets to repeat often enough.”

“So Mars has big stuff because…”

“The planet’s too cold to wear it away.”

~~ Rich Olcott

Raindrops landing in a red-brown puddle
Adapted image from Clipart-library.com

The Big Splash? Maybe.

You’ve not seen half of it, Mr Feder.  Mars has the Solar System’s tallest volcano, most massive volcano, biggest planetary meteor strike, deepest and longest  canyon…”

“Wait, kid, I’ve been to the Grand Canyon.  Thing is … BIG!  What’d they say?  A mile deep, 18 miles wide, 250 miles long.  No way Mars can beat that.”

“Valles Marineris is 4½ miles deep, 120 miles wide and 2500 miles long.  The Grand Canyon meanders, packing its length into only 150 miles of bee-line distance.  Marineris stretches straight as a string.  No river carved that formation, but the planetologists can’t agree on what did.”

Labeled Mars map 2 420
Mars map from NASA/JPL/GSFC

“They got evidence, don’t they?”

“Not enough.  Different facts point in different directions and no overall theory has won yet.  Most of it has to do with the landforms.  Start with the Tharsis Bulge, big as a continent and rising kilometers above Mars’ average altitude.  Near the Bulge’s highest point, except for the volcanoes, is a fractured-looking region called Noctis Labyrinthus.  Starting just west of  the Labyrinth a whole range of wrinkly highlands and mountains arcs around south and then east to point towards the eastern end of Marineris.  Marineris completes the arc by meeting the Labyrinth to its west.  Everything inside that arc is higher than everything else around it.  Except for the volcanoes, of course.”

“Looks like something came up from underneath to push all that stuff up.”

“Mm-hm, but we don’t know what, or what drove it, or even how fast everything happened.  There are theories all over the place”

“Like what?”

“Well, maybe it’s upwellng from a magma hotspot, like the one under the Pacific that’s been creating Hawaiian Islands one at a time for the past 80 million years.  Some people think the upwelling mostly lifted the existing crust like expanding gas bubbles push up the crust of baking bread.  Other people think that the upwelling’s magma broke through the crust to form enormous lava flows that covered up whatever had been there before.”

“You said ‘maybe.'”

“Yeah.  Another group of theories sees a connection between Tharsis and Hellas Basin, which is almost exactly on the other side of the planet.  Hellas is the rock-record of a mega-sized meteorite strike, the third largest confirmed one in the Solar System.  Before you ask, the other two are on the Moon.  Like I said, it’s a group of theories.  The gentlest one, if you can call it that, is that energy from the impact rippled all around the planet to focus on the point opposite the impact.  That would have disrupted the local equilibrium between crustal weight and magma’s upward pressure.  An imbalance like that would encourage uplift, crustal cracking and, ultimately, Valles Marineris.”

“Doesn’t sound very gentle.”

“It wouldn’t have been but it might even have been nastier.  Another possibility is that the meteorite may not have stopped at the crust.  It could have hit hard enough, and maybe with enough spin, to drill who knows how far through the fluid-ish body of the planet, raising the Bulge just by momentum and internal slosh.  Worst case, some of Tharsis’ rock might even have come from the intruder.”

Realistic Orange-red Liquid Splash Vector
Adapted from an image by Vecteezy

“Wow, that would have been a sight to see!”

“Yeah, from a distance.  Any spacecraft flying a Mars orbit would be in jeopardy from rock splatter.  We’ve found meteors on Earth that we know originated on Mars because they have bubbles holding trapped gas that matches the isotope signature of Martian atmosphere.  A collision as violent as the one I just described could certainly have driven rocky material past escape velocity and on its way to us.  Oh, by the way and speaking of sights — you’d be disappointed if you actually visited Valles Marineris.”

“How could anything that ginormous be a disappointment?”

“You could look down into it but you probably couldn’t see the far side.  Mars is smaller than Earth and its surface curves downward more rapidly.  Suppose you stood on one side of the valley’s floor where it’s 4 miles deep.  The opposite wall, maybe 100 miles away, would be beyond your 92-mile horizon limit for an object that tall.”

“Aw, phooey!”

~~ Rich Olcott

Holes in The Ground — Big Ones

Al’s stacking chairs on tables, trying to close his coffee shop, but Mr Richard Feder (of Fort Lee, NJ) doesn’t let up on Jim.  “What’s all this about Gale Crater or Mount Sharp that Curiosity‘s running around?  Is it a crater or a mountain?  How about it’s a volcano?  How do you even tell the difference?”

That’s a lot of questions but Jim’s got game.  “Gale is an impact crater, about three and a half billion years old.  The impacting meteorite must have hit hard, because Mount Sharp’s in the middle of Gale.”

Mud drop
Adapted from a photo
by Davide Restivo, Aarau, Switzerland
[CC BY-SA 2.0] via Wikimedia Commons
“How’s that follow?”

“Have you ever watched a rain drop hit a puddle?  It forces the puddle water downward and then the water springs back up again to form a peak.  The same general process  happens when a meteorite hits a rocky surface except the solid peak doesn’t flatten out like water does.  We know that’s the way many meteor craters on the Moon and here on Earth were formed.  We’re pretty sure it’s what happened at Gale — the core of Mount Sharp (formal astronomers call it Aeolis Mons) is probably that kind of peak.”

“Only the core?  What about the rest of it?”

“That’s what Curiosity has been digging into.”  <I have to smile — Jim’s not one to do puns on purpose.>  “The rover’s found evidence that the core’s wrapped up in lots of sedimentary clays, sulfates, hematites and other water-derived minerals of a sort that wouldn’t be there unless Gale had once been a lake like Oregon’s Crater Lake.  That in turn says that Mars once had liquid water on its surface.  That’s why everyone got so excited when those results came in.”

“Oregon’s Crater Lake was from a meteorite?”

“Oops, bad example.  No, that one’s a water-filled volcanic caldera.”

“How do you know?  Any chance its volcano will blow?”

“The best evidence, of course, is the mineralogy.  Volcanoes are made of igneous rocks — lava, tefra and everything in between.  Impact craters are made of whatever was there when the meteorite hit, although the heat and the pressure spike transform a lot of it into some metamorphic form.”

“But you can’t check for that on Mars or the Moon.”

“Mostly not, you’re right, so we have to depend on other clues.  Most volcanoes, for instance, are above the local landscape; most impact structures are below-level.  There are other subtler tests, like the pattern and distance that ejecta were thrown away from the event.  In general we can be 95-plus percent sure whether we’re looking at a volcano or an impact crater.  And no, it won’t any time soon.”

“What won’t do what?”

“You asked whether Crater Lake’s volcano will erupt.  Mount Mazama blew up 7700 years ago and it’s essentially been dormant ever since.”

“There’s some weasel-wording back there — most volcanoes do this, most impacts do that.  What about the exceptions?”

“Those generally have to do with size.  The really enormous features are often hard to even recognize, much less classify.  On Mars, for instance the Northern Lowlands region is significantly smoother than most of the rest of the planet.  Some people think that’s because it’s a huge lava flow that obliterated older impact structures.  Other people think the Lowlands is old sea bottom, smooth because meteorites would have splashed water instead of raising rocky craters.”

Labeled Mars map 420
Mars map from NASA/JPL/GSFC

“I’ll bet ocean.”

“There’s more.  You’ve heard about Olympus Mons on Mars being the Solar System’s biggest volcano, but that’s really only by height.  Alba Mons lies northeast of Olympus and is far huger by volume — 600 million cubic miles of rock but it’s only 4 miles high.  Average slope is half a degree — you’d never notice the upward grade if you walked it.  Astronomers thought Alba was just a humungous plain until they got detailed height data from satellite measurements.”

“The other one’s more than 4 miles high?”

“Oh, yeah.  Olympus Mons rises about 13.5 miles from the base of its surrounding cliffs.  That’s more than the jump from the bottom of the Mariana Trench to the top of Mount Everest.”

“Things on Mars are big, alright.”

~~ Rich Olcott

 

Why Is Mars Red But Earth Is Blue?

The grad students’ Crazy Theory Contest event at Al’s coffee shop is breaking up.  Amanda’s flaunting the Ceremonial Broom she won with her ‘Spock and the horseshoe crabs‘ theory.  Suddenly a voice from behind me outroars the uproar.  “Hey, Mars guy, I got questions.”

Jim looks up and I look around.  Sure enough, it’s Mr Richard Feder.  I start with the introductions but he barrels right along.  “People call Mars the Red Planet, but I seen NASA pictures and it’s brown, right?  All different kinds of brown, with splotches.  There’s even one picture with every color in the rainbow.  What’s with that and what color is Mars really?”

Jim’s a newly-fledged grad student so I step in to give him a chance to think.  “That rainbow picture, Mr Feder, did it have a circular purple spot about a third of the way up from the bottom and was it mostly blue along the top?”

“Yeah, sounds about right.”

“That’s a NASA topographic map, color-coded for relative elevations, purple for low areas to red high-up.  The blue area is the Northern Lowlands surrounding the North Pole, and that purple spot is Hellas Basin, a huge meteor crater billions of years old.  It’s about 5 miles deep which is why they did it in purple.  The map colors have nothing to do with the color of the planet.”

“About your question, Mr …. Feder is it?”

“Yeah, kid, Richard Feder, Fort Lee, New Jersey.”

“Good to meet you, sir.  The answer to your question is, ‘It depends.’  Are you looking down from space or looking around on the surface?  And where are you looking?  Come to think of it, when are you looking?”

“All I’m asking is, is it red or not?  Why make it so complicated?”

“Because it is complicated.  A few months ago Mars had a huge dust storm that covered the whole planet.  At the surface it was far darker than a cloudy moonless night on Earth.  From space it was a uniform butterscotch color, no markings at all.”

“OK, say there’s no dust in the air.”

“Take away all the floating dust and it almost wouldn’t be Mars any more.  The atmosphere’s only 1% of Earth’s and most of that is CO2 — clear and colorless.”

“So what would we see looking down at the surface?”

“Uh … you’re from New Jersey, right?  What color is New Jersey’s surface?”

<a little defensively> “We got a lot of trees and farms, once you get away from all the buildings along the coast and the Interstates, so it’s green.”

“Mars doesn’t have trees, farms, buildings or roads.  What color is New Jersey underneath all that?”

“The farmland soil’s black of course, and the Palisades cliffs near me are, too.  Down-state to the south we got sand-colored sand on the beaches and clay-colored clay.”

“Mars has clay, the Curiosity rover confirmed that, and it’s got basalt like your cliffs, but it has no soil.”

“Huh? How could it not have soil?  That’s just ground-up rocks, right, and Mars has rocks.”

“Soil’s way more then that, Mr Feder.  If all you have is ground-up rocks, it’s regolith.  The difference is the organic material that soil has and regolith doesn’t — rotted vegetable matter, old roots, fungus, microorganisms.  All that makes the soil black and helps it hold moisture and generally be hospitable to growing things.  So far as we know, Mars has none of that.  We’ve found igneous, sedimentary and metamorphic rocks just like on Earth; we’ve found clays, hematites and gypsum that had to have been formed in a watery environment.  But so far no limestone — no fossilized shelly material like that would indicate life.”

“What you’re saying is that Mars colors look like Earth colors except no plants.  So why do astronomers call Earth a ‘pale blue marble’ but Mars is ‘the red planet’?”

“Earth looks pale blue from space.  The blue is the dominant color reflected from the 70% of Earth’s surface that’s ocean-covered.  It’s pale because of white light reflected from our clouds of water vapor.  Mars lacks both.  What Mars does have is finely-divided iron oxide dust, always afloat above the surface.”

“Mars looks red ’cause it’s atmosphere is rusty?”

“Yessir.”Earth and Mars

~~ Rich Olcott

Atoms are solar systems? Um, no…

Suddenly there’s a hubbub of girlish voices to one side of the crowd.  “Go on, Jeremy, get up there.”  “Yeah, Jeremy, your theory’s no crazier than theirs.”  “Do it, Jeremy.”

Sure enough, the kid’s here with some of his groupies.  Don’t know how he does it.  He’s a lot younger than the grad students who generally present at these contests, but he’s got guts and he grabs the mic.

“OK, here’s my Crazy Theory.  The Solar System has eight planets going around the Sun, and an oxygen atom has eight electrons going around the nucleus.  Maybe we’re living in an oxygen atom in some humongous Universe, and maybe there are people living on the electrons in our oxygen atoms or whatever.  Maybe the Galaxy is like some huge molecule.  Think about living on an electron in a uranium atom with 91 other planets in the same solar system and what happens when the nucleus fissions.  Would that be like a nova?”

There’s a hush because no-one knows where to start, then Cathleen’s voice comes from the back of the room.  Of course she’s here — some of the Crazy Theory contest ring-leaders are her Astronomy students.  “Congratulations, Jeremy, you’ve joined the Honorable Legion of Planetary Atom Theorists.  Is there anyone in the room who hasn’t played with the idea at some time?”

No-one raises a hand except a couple of Jeremy’s groupies.

“See, Jeremy, you’re in good company.  But there are a few problems with the idea.  I’ll start off with some astronomical issues and then the physicists can throw in some more.  First, stars going nova collapse, they don’t fission.  Second, compared to the outermost planet in the Solar System, how far is it from the Sun to the nearest star?”

A different groupie raises her hand and a calculator.  “Neptune’s about 4 light-hours from the Sun and Alpha Centauri’s a little over 4 light-years, so that would be … the 4’s cancel, 24 hours times 365 … about 8760 times further away than Neptune.”

“Nicely done.  That’s a typical star-to-star distance within the disk and away from the central bulge.  Now, how far apart are the atoms in a molecule?”

“Aren’t they pretty much touching?  That’s a lot closer than 8760 times the distance.”

“Yes, indeed, Jeremy.  Anyone else with an objection?  Ah, Maria.  Go ahead.”

“Yes, ma’am.  All electrons have exactly the same properties, ¿yes? but different planets, they have different properties.  Jupiter is much, much heavier than Earth or Mercury.”

Astrophysicist-in-training Jim speaks up.  “Different force laws.  Solar systems are held together by gravity but at this level atoms are held together by electromagnetic forces.”

“Carry that a step further, Jim.  What does that say about the geometry?”

“Gravity’s always attractive.  The planets are attracted to the Sun but they’re also attracted to each other.  That’ll tend to pull them all into the same plane and you’ll get a flat disk, mostly.  In an atom, though, the electrons or at least the charge centers repel each other — four starting at the corners of a square would push two out of the plane to form a tetrahedron, and so forth.  That’s leaving aside electron spin.  Anyhow, the electronic charge will be three-dimensional around the nucleus, not planar.  Do you want me to go into what a magnetic field would do?”

“No, I think the point’s been made.  Would someone from the Physics side care to chime in?”

“Synchrotron radiation.”

“Good one.  And you are …?”

“Newt Barnes.  I’m one of Dr Hanneken’s students.”

“Care to explain?”

“Sure.  Assume a hydrogen atom is a little solar system with one electron in orbit around the nucleus.  Any time a charge moves it radiates waves into the electromagnetic field.  The waves carry forces that can compel other charged objects to move.  The distance an object moves, times the force exerted, equals the amount of energy expended by the wave.  Therefore the wave must carry energy and that energy must have come from the electron’s motion.  After a while the electron runs out of kinetic energy and falls into the nucleus.  That doesn’t actually happen, so the atom’s not a solar system.”

Jeremy gets general applause when he waves submission, then the crowd’s chant resumes…

.——<“Amanda! Amanda! Amanda!”>Bohr and Bohr atom

~~ Rich Olcott

Helios versus Mars, Planetary Version

Al waves me over the moment I step through the door of his coffee shop.  “Sy, ya gotta squeeze into the back room.  The grad students are holding another Crazy Theory contest and they’re having a blast.  I don’t know enough science to keep up with ’em but you’d love it.  Here’s your coffee.”

“Thanks, Al.  I’ll see what’s going on.”

The Crazy Theory contest is a hallowed Al’s Coffee Shop tradition — a “seminar” where grad students present their weirdest ideas in competition.  Another tradition (Al is strong on this one) is that the night’s winner has to sweep up the thrown spitballs and crumpled paper napkins at the end of the presentations.  I weave my way in just as the girl at the mic finishes her pitch with, “… and that’s why Spock and horseshoe crabs both have green blood!”

Some in the crowd start chanting “Amanda!  Amanda!  Amanda!”  She’s already reaching for the Ceremonial Broom when Jim steps up to the mic and waves for quiet.  “Wanna hear how the Sun oxidized Mars and poisoned it for us?”

Helios and Mars
Helios and Mars
Mars image adopted from photo by Mark Cartwright
Creative Commons license
Attribution-NonCommercial-ShareAlike

Voice from the crowd — <“The Sun did what?”>

“You remember titration from school chem lab?”

.——<“Yeah, you put acid in a beaker and you drip in a base until the solution starts to turn red.”>

“What color is Mars?”

.——<“Red!”>

“Well, there you are.”

.——<“Horse-hockey!  What’s that got to do with the Sun or what you said about poison?”>

“Look at what our rovers and orbiters found on Mars — atmosphere only 1% of Earth’s but even that’s mostly CO2, no liquid water at the surface, rust-dust everywhere, soil’s loaded with perchlorate salts.  My Crazy Theory can explain all of that.”

.——<“Awright, let’s hear it!”>

“Titration’s all about counting out chemical species.  Your acid-base indicator pinked when you’d neutralized your sample’s H+ ions by adding exactly the right number of OH ions to turn them all into H2O, right?  So think about Mars back in the day when it had liquid water on the ground and water vapor in the atmosphere.  Along comes solar radiation, especially the hard ultra-violet that blows apart stratospheric H2O molecules.  ZOT!  Suddenly you’ve got two free hydrogen atoms and an oxygen floating around.  Then what happens?”

It’s a tough crowd.  <“We’re dying to hear!  Get on with it!”>

“The hydrogens tie up as an H2 molecule.  The escape velocity on Mars is well below the speed of H2 molecules at any temperature above 40K, so those guys abandon Mars for the freedom of Space.  Which leaves the oxygen atom behind, hungry for electrons and ready to oxidize anything it can get close to.”

They’re starting to come along.  <“Wouldn’t the oxygen form O2 and fly away too?”>

“Nowhere near as quickly.  An O2 molecule is 16 times heavier than an H2 molecule.  At a given temperature it moves 1/4 as fast and mostly stays on-planet where it can chew up the landscape.”

.——<“How could an atom do that?”>

“It’s a chain process.  First step for the O is to react with something else in the atmosphere — make an oxidizing molecule like ozone or hydrogen peroxide.  That diffuses down to ground level where it can eat rocks.”

.——<“Wait, ‘eat rocks’!!?!  How does that happen?”>

“Look, most rocks are basically lattices of double-negative oxide ions with positive metal ions tucked in between to balance the charge.  Surface oxide ions can’t be oxidized by an ozone molecule, but they can transmit electron demand down to the metal ions immediately underneath.  An iron2+ ion gets oxidized to iron3+, one big step towards rust-dust.  The charge change disrupts the existing oxide lattice pattern and that piece of the rock erodes a little.”

.——<“What about the poison?”>

“Back when Mars had oceans, they had to have lots of chloride ions floating around to be left behind when the ocean dried up.  Ozone converts chloride to perchlorate, ClO4, which is also a pretty good oxidizer.  Worse, it’s the right size and charge to sneak into your thyroid gland and mess it up.  Poison for sure.  Chemically, solar radiation raised the oxidation state of the whole planet.”

One lonely voice — “Nice try, Jim” — but then the chant returns…

.——<“Amanda!  Amanda!  Amanda!”>

~~ Rich Olcott

A Recourse to Pastry

There’s something wrong about the displays laid out on Al’s pastry counter — no symmetry.  One covered platter holds eight pinwheels in a ring about a central one, but the other platter’s central pinwheel has only a five-pinwheel ring around it.  I yell over to him.  “What’s with the pastries, Al?  You usually balance things up.”

“Ya noticed, hey, Sy?  It’s a tribute to the Juno spacecraft.  She went into orbit around Jupiter on the 5th of July 2016 so I’m celebrating her anniversary.”

“Well, that’s nice, but what do pinwheels have to do with the spacecraft?”

“Haven’t you seen the polar pictures she sent back?  Got a new poster behind the cash register.  Ain’t they gorgeous?”Jupiter both poles“They’re certainly eye-catching, but I thought Jupiter’s all baby-blue and salmon-colored.”

Astronomer Cathleen’s behind me in line.  “It is, Sy, but only in photographs using visible sunlight.  These are infrared images, right, Al?”

“Yeah, from … lemme look at the caption … Juno‘s JIRAM instrument.”

“Right, the infrared mapper.  It sees heat-generated light that comes from inside Jupiter.  It’s the same principle as using blackbody radiation to take a star’s temperature, but here we’re looking at a planet.  Jupiter’s way colder than a star so the wavelengths are longer, but on the other hand it’s close-up so we don’t have to reckon with relativistic wavelength stretching.  At any rate, infrared wavelengths are too long for our eyes to see but they penetrate clouds of particulate matter like interstellar dust or the frigid clouds of Jupiter.”

Jupiter south pole 1
NASA mosaic view of Jupiter’s south pole by visible light

“So this red hell isn’t what the poles actually look like?”

“No, Al,  the visible light colors are in the tops of clouds and they’re all blues and white.  These infrared images show us temperature variation within the clouds.  Come to think of it, that Hell’s frozen over — if I recall correctly, the temperature range in those clouds runs from about –10°C to –80°C.  In Fahrenheit that’d be from near zero to crazy cold.”

“Those aren’t just photographs in Al’s poster?”

“Oh, no, Sy, there’s a lot of computer processing in between Juno‘s wavelength numbers and what the public sees.  The first step is to recode all the infrared wavelengths to visible colors.  In that north pole image I’d say that they coded red-to-black as warm down to white as cool.  The south pole image looks like warmest is yellow-to-white, coolest is red.”

“How’d you figure that?”

“The programs fake the apparent heights.  The warmest areas are where we can see most deeply into the atmosphere, which would be at the center or edge of a vortex.  The cooler areas would be upper-level material.  The techs use that logic to generate the perspective projection that we interpret as a 3-D view.”

Vinnie’s behind us in line and getting impatient.  “I suppose there’s Science in those pretty pictures?”

“Tons of it, and a few mysteries.  JIRAM by itself is telling the researchers a lot about where and how much water and other small molecules reside in Jupiter’s atmosphere.  But Juno has eight other sensors.  Scientists expect to harvest important information from each of them.  Correlations between the data streams will give us exponentially more.”

He’s still antsy.  “Such as?”

“Like how Jupiter’s off-axis magnetic field is related to its lumpy gravitational field.  When we figure that out we’ll know a lot more about how Jupiter works, and that’ll help us understand Saturn and gas-giant exoplanets.”GRS core

Al breaks in.  “What about the mysteries, Cathleen?”

“Those storms, for instance.  They look like Earth-style hurricanes, driven by upwelling warm air.  They even go in the right direction.  But why are they crammed together so and how can they stay stable like that?  Adjacent gears have to rotate in opposite directions, but these guys all go in the same direction.  I can’t imagine what the winds between them must be like.”

“And how come there’s eight in the north pole ring but only five at the other pole?”

“Who knows, Vinnie?  The only guess I have is that Jupiter’s so big that one end doesn’t know what the other end’s doing.”

“Someone’s gonna have to do better than that.”

“Give ’em time.”

~~ Rich Olcott