Mass of the Solar System

The Sun is 99.8% of the mass of the solar system.  Jupiter is about 70% of all the mass in the solar system that is not the sun.  Ganymede, the Moon, and all the dwarf planets and moons are all less massive than Mercury, most by a lot. The total mass of the asteroid belt and all the comets is around 3e21...way less.   It's remotely possible that there's something big in the Oort cloud, but unlikely.

The lightest brown dwarfs are believed to mass abut 2.5e28 kg, roughly 13 times heavier than Jupiter.  The lightest actual stars are believed to mass about 1.5e29, about 75 times the mass of Jupiter. 

The solar system is the sun plus little stuff.  There will never be another sun in the solar system, unless it captures a passing star.


mass in kg, diameter and distance in km

Name	Mass	Diameter	Distance from Sun
Sun	1.9891e30	1.39e6	0
Mercury	3.3e23	4889	5.7e7
Venus	4.87e24	1.20e4	1.08e8
Earth	5.97e24	1.27e4	1.50e8
Mars	6.42e23	6779	2.28e8
Jupiter	1.90e27	1.40e5	7.80e8
Saturn	5.68e26	1.16e5	1.43e9
Uranus	8.68e25	5.01e4	2.87e9
Neptune	1.02e26	4.92e4	4.5e9
Planets	2.68e27

2019 Calendar

Tue 1 Jan      New Year's Day
Mon 21 Jan   Martin Luther King Day (Holiday)
Sat 2 Feb      Groundhog's (midwinter) Day
Sun 3 Feb     Superbowl LIII, Atlanta, GA
Tue 5 Feb     Chinese New Year, begins year of the Pig, 4717
Mon 18 Feb  Presidents Day (Holiday)
Sun 10 Mar   Daylight Savings Time begins  
Wed 20 Mar  21:58UT (14:58PDT)  Spring Equinox
Fri 19 Apr     Passover begins at sundown
Sat 20 Apr      Passover ends at sundown
Sun 21 Apr      Easter
Wed 1 May     May Day (midspring)
Sun 5 May      Ramadan begins
Mon 27 May  Memorial Day (Holiday)
Tue 4 Jun       Ramadan ends 
Fri 21 Jun    15:54UT (08:54PDT) Summer Solstice
 Thu 4 Jul       Independence Day (Holiday)
Thu 1 Aug     Midsummer day   
Mon 2 Sep     Labor Day (Holiday)
Mon 23 Sep     07:50UT (00:50PDT) Autumn Equinox
Sun 29 Sep      Sundown Rosh Hashana begins year 5780
Tue 8 Oct       Sundown Yom Kippur
Mon 14 Oct    Columbus Day (Holiday for some people)
Thu 31 Oct     Hallowe'en
Fri 1 Nov      Mid autumn day
Sun 3 Nov      Daylight Savings Time ends 
Mon 11 Nov    Veterans Day  
Thu 28 Nov   Thanksgiving (Holiday)
Fri 29 Nov     Holiday
Sun 22 Dec     Sundown  Hannuka begins
Sun 22 Dec    04:19UT (Sat 21Dec 20:19PST) Winter Solstice 
Wed 25 Dec   Christmas (Holiday)
Mon 30 Dec   Sundown, Hannuka ends



Days off work in bold

Astronomical and calendar events in italic

Media misuse of words

Ballistic.  Ballistics is the study of the inertial motion of objects under the influence of gravity, windage, momentum and so forth, with no midflight attempt to change speed or direction.  To "go ballistic" means to stop trying to control the vehicle, to let inertia do its work.  In the scene in the movie Top Gun where the pilots were talking about this, they meant they were going so fast they kept going for quite a while, despite throttling down.  Going really fast under high power and in control is NOT ballistic.  If an athlete or car loses control after going really fast and crashes through a barrier, that is ballistic.

Cache and cachet.  A cache (pronounced "cash") is a small store of something, stored away for later, or the act of storing something in such a place.  Cachet (pronounced "ca-shay") is the prestige or fashionableness of something.  A few days ago, a soldier was pointing to the pile of crates he and his men had dug up in Afghanistan, describing them as a "cachet" of weapons.

Could care less.  A lot of people say this when what they actually mean is "couldn't care less".  If you could care less, it's because there's still room for you to care less, that is to say, you do still care, at least a little bit.  If you couldn't care less, it's as if to say your care-meter on this subject has bottomed out.

Decimation -- people seem to think this is much worse than "Devastation" but not necessarily.  Decimation was a punishment the Romans meted out, most often to legions that had displayed cowardice in action.  They'd execute one in ten, chosen at random, to scare the others into acting better next time.  So if the bad thing completely destroyed about 10%, leaving the rest relatively untouched, that's decimation.  If the bad thing destroyed 50%, that's much worse than decimation.

Gridlock refers to a specific type of traffic jam, one which is the result of multiple backups in an urban grid intermeshing in such a way as to prevent any of them from moving.  The term is a merging of "Grid" and "Deadlock".  I often hear the giant traffic jam that occurs when the mountain pass is blocked, or a due to a blocking accident as gridlock.   There's no grid in the mountain pass.  Snowlock maybe. The grid, if there is one, is irrelevant to the blocked road.

A Hacker is a computer programmer who works quickly, often by modifying existing code (the etymology is from "Hack and Slash", and to those who do it, the simile is apt).  The implication is that this is also sloppily done, although a number of the very best are neat workers too.  The media has decided that people who break into and vandalize computers or steal data or software should be called hackers.  Some of them are hackers, but most are not and most hackers don't break into computers.  Many worms and viruses are probably written by hackers, but most hackers do not do these things.  A better term for those who break and enter computers is “computer cracker”—in the sense of “safe cracker”--or "vandal".

 

An Implosion is a specific type of kaboom.  A kaboom where the detritus goes outwards is an explosion.  A kaboom where the detritus goes inward is an implosion.  A recent trend in building demolition has been to use a large number of small explosive charges to simultaneously (or sometimes sequentially over a short period) undermine the structure of a building so as to make it collapse inwards on itself...an implosion.  The triggering charge for an atomic bomb is an implosion.  Once critical mass is achieved, the fissionable material of the bomb then undergoes an explosion.   Many in the media have taken to calling any kaboom an implosion, apparently because they think it sounds more cool.

Unthinkable means you literally couldn't think of it before it happened, either because nobody had the idea, (as in "previously unimagined".  Sept 11 may qualify for this) or because thinking about the topic causes the mind to rebel and you can't get your mind go there.  Disgusting and offensive as it is, child molestation is clearly not unthinkable, because lots of bad people have not only thought about it, but done it.  The second time some particular reporter says that a child molester has done the unthinkable, they're not telling you that the crime is unthinkable, but that the reporter can't think.  Personal favorite, from an actual reporter and former pro football player here in Seattle: "Once again, the unthinkable has occurred."

Words have meaning.

(Bertrand Russell tells a story where one of his house staff was accused of stealing something.  She defended herself by saying: "I ain't never stole nothing".  Russell, ever the logician, works through the logic of this statement, which literally translated,  means that there does not exist a time in all of history at which she has not stolen something.  or put more simply, she has *always* (including before she was born) been stealing something.)

Natural Selection and the Tillman Act

Noam Chomsky calls the Republican Party the most dangerous organization in the history of the world.  We humans now have it in our power to destroy all human life on the planet in two different ways (global warming and nuclear holocaust--bioweapons may be a third) and the Republican are actively standing in the way of doing anything to fix either--indeed they seem to be pursing policies designed to make both situations profoundly more serious.  Chomsky is right about the danger of the Republicans, and they need to be eliminated from government, but I think we need to keep in mind Hanlon's Razor: Never attribute to malice that which can be explained by stupidity.

The entities that are doing the damage are mostly corporations.  A corporation is an entity which is created to organize some project or projects (usually making money for its owners) and limit their legal liability should something go wrong.  It is like an animal that has no brain: it lives in an environment (the economy) governed by a set of rules which provide automatic response to a wide range of situations (usually to maximize profits or shareholder value) but need active intervention by the board of directors to make any consequential change to those rules.   Natural selection tends to breed corporations that do the best job of maximizing short term profit, irrespective of long term consequences.

Within the corporation are humans who do have brains, but their power is limited to their ability to sway a majority of votes on the board of directors.  Many large shareholders (e.g. endowments and large trusts) maintain an official policy of abstaining, and small shareholders usually abstain too, so garnering an actual majority to overturn a destructive policy is very, very difficult.   Over the years there have been a number of laws and policies devised to minimize the consequences of this--e.g. anti monopoly law, restraint of trade laws, the Tillman Act of 1907 (which makes it illegal for corporations to donate to political campaigns), the Glass-Steagall law (which imposed a wall between speculative banking and mainstream banking), but most of them have been overturned or emasculated by short sighted politicians in the pay of corporations in recent years, or their judicial puppets.

A brainless corporation can be very powerful, and it is not limited by human lifespans, and it may have effective employees serving its short sighted goals as strongly as they can, without necessarily recognizing their destructiveness.  The Russian word for such people is "Apparatchiks", and if they are allowed to do it, these apparatchiks may be members of congress and and executives of the government.  The reason the Republican party is so dangerous is because many of them are apparatchiks, serving the goals of the brainless corporations and nothing else.  For oil and coal companies, a way to maximize profits is to maximize the production of greenhouse gasses and minimize controls on pollution.  For banks, the way to maximize profits is to minimize limitations on the sorts of investments they can do, without regard to possible consequences.  For most companies, getting government payouts is a good thing.

We need to restore limits on corporate power.   Things like the Tillman act limited the brainless corporations power in government.  Their apparatchiks could still participate in politics, but they were personally involved, which imposed limits.  The Citizens United decision effectively eliminated this control, and without it Natural Selection effectively forces corporations to become bad actors.  We need to adjust things so corporations or at least their employees have a strong incentive to look out for the long term health of the environment and economy.  This probably means breaking up large corporations, taxing harmful behaviors like polluting, mandating that they provide clean safe transit for the communities they serve, and so forth.  I think there are a number of industries which are almost purely harmful and should either be eliminated or nationalized.  For example, high frequency trading of stocks does nothing productive at all except make money, and it distorts the stock market.  It should be banned.  Health insurance serves no purpose but to make health care more expensive and harder to obtain.  It should be nationalized and made available free for all.  Lots more.

 Ultimately, what we need to do is make corporations act like good citizens. Their limited liability is central to their ability to do serious harm.  One of the most powerful things we can do is make sure corporate officers are liable for the harmful things they do.  If an executive tells an employee to get rid of this toxic stuff, and does not offer any direction to do it a responsible way, the executive needs to be punished.  If an executive bribes a politician, whether tacit or explicit, direct or indirect, that executive should be punished severely enough that they will not be able to do it again.

Dark Ages

Several times in human history, a great civilization has flourished, made great technological, political, and other advances, and then collapsed into a Dark Age.  These dark ages seem to last for 800 to 1000 years, whereupon a completely different civilization, often with dim memories of the old one, may arise.  The two archetypical examples are the fall of Mycenae in around 1177 BC and the rise of Greece and its inheritor Rome, about 1000 years later, followed by the fall of Rome in 476 and the Renaissance, which began in around 1300.

What is a dark age?  Mostly, it is dark in comparison to what came before.   During civilization, the value of civilization seems obvious.  Trade is relatively unencumbered by banditry, roads are built, technological advances come frequently and spread fast.  Authority is relatively stable and widely respected.  Cities don't need to have walls.  During a dark age, travel is dangerous and banditry is expected.  There is little or no agreed authority and people and groups vying for power are constantly trying to kill each other.  Cities and the homes of wealthy people are strongly guarded, with walls and soldiers and those defenses are frequently tested.  Invention is still happening, but they tend to be isolated and advances spread relatively slowly.

Dark ages are never completely dark.  Writing was invented around the time of the fall of Mycenae and was constantly developed and improved during the ensuing dark age.  Much of the strength of the books that survive from those times is precisely that the newly literate peoples had a dim memory of the ancients, carried by oral traditions, and had enlarged and exaggerated the greatness of those old stories, until by the point they are written down, Achilles, Gilgamesh, Beowolf, David, King Arthur, and many others are impossibly great warriors with magical powers and frequent interactions with the gods.  Once they are written down, it's impossible for real people to match the great deeds, and during the dark age, the old civilization can only be conceived of as impossibly wonderful.  This hero worship tends to infect the dark age and makes it more difficult for the new civilization to emerge.

What causes dark ages?   Sometimes, there is an active decapitation:  after 1492, Europeans made their first successful footholds in the Americas.  They brought with them new types of weapons and tools, horses, and most significantly, new diseases which the natives didn't have defenses for, the most important of which was smallpox.  Less than 30 years after Columbus, Mexico was so devastated that Cortez was able to capture it and impose Spain's peculiar brand of fundamentalism, and 130 years later, the Pilgrims arrived in Massachusetts to discover cleared but empty fields and groups of natives too small to eke out a living on them and willing to teach the new settlers how to grow native crops in the new fields.  The native cultures were systematically destroyed. Smallpox did most of the work, but the survivors were made slaves and for the most part not allowed to participate in the new civilization unless they completely abandoned the old one.  The places that remain substantially native: the reservations in the US and the countless villages in Latin America, especially those which had Spanish fundamentalism imposed on them, are indistinguishable from their counterparts in dark age Europe.

Far more common is the local rise of religious fundamentalism.  Rome had been very multicultural and tolerant, and this was central to their success, but 100 years after they embraced Christianity, they began persecuting other religions and even small deviations from what Christian leadership determined was "correct" Christianity were persecuted.  There were other causes too, but the great historian Edward Gibbon argues persuasively that Christian Fundamentalism so weakened Roman culture that it could not survive.

Not long after Rome collapsed and not too far away, another great civilization was rising.  It was powered by Islamic expansionism but in a few places, most importantly Baghdad and Cordoba, great centers of learning were being established.  Like all great centers of learning, they embraced other cultures and religions enthusiastically and made many advances in many fields--mathematics, astronomy, metallurgy and many others.  They collected as much as they could of their recently deceased neighbor.  But they too collapsed because of religious fundamentalism, and much of their world continues to be held back by it--by the Wahabbi Saud family, by the Ayatollahs, the Taliban, and so forth.

The Renaissance arose where and when it did because dark age traders, mostly from Florence and Venice, were interested in Islamic cultures and traded with them--commercial products mostly, but also books.  Cosimo de Medici, one of the greatest bankers to ever live (he invented double entry bookkeeping) and the richest man in Italy that was not the pope, collected every book he could--bought it if possible, had it transcribed if he couldn't, and his heirs continued this legacy.  Many of the books were Arabic translations of Roman and Greek books whose originals had been lost or intentionally destroyed by the Christian fundamentalists. That this was happening just as Islamic fundamentalism was arising and so soon after the crusades gave the fundamentalists a target for their anger.

Western European culture that began with the Renaissance and expanded to North America appears to be embracing another round of fundamentalism and anti-multiculturalism.  It is being helped along by Russian trolls no doubt, but there would be no traction were there not a fertile opportunity,  Fundamentalism is the civilization killer.

Worst Attacks on America

The United States of America has been attacked by foreign powers a number of times.  Here, in decreasing order of severity, are the worst 8, in my opinion.

Fort Sumter 12-13 Apr 1861.   South Carolina militias, unhappy with the results of the 1860 election and determined to preserve their right to enslave human beings, secede from the Union and fire artillery upon the Union Fort in Charleston harbor, starting the Civil War.

Pearl Harbor 7 Dec 1941.   A Japanese surprise attack on the US Naval base at Pearl Harbor, Oahu, Hawaii, kills about 2400 US soldiers and civilians, sinks 4 battleships and damages more than a dozen other ships, and provokes US entry into WWII

Donald Trump 8 Nov 2016.  Forces loyal to Russia corrupt the US election and elect a conman who is their puppet president.  He and his allies proceed to undermine US media, foreign relations, judiciary and democratic processes, plainly intending to undermine American credibility and our place in the world.  It remains unclear how this will turn out.

1812 The British, annoyed by the loss of their prime colonies on the American continent, tried to prevent further losses farther inland and into Canada, and blockaded US ports, impressing American soldiers onto British warships during their long war against France, by this point led by Napoleon.  War was declared in June 1812 and in August 1814, the British sacked and burned the White House and Capitol.  Peace was finally signed in Dec 1814.  This is the only time a foreign power ever tried direct military action against the US mainland.

Submarine attacks during WWI.  During World War I, America had initially tried to remain neutral, but the commercial connection to the British and French were strong and shipping and travel continued across the Atlantic, albeit under attack by German U-boats.  Their leaders constantly pleaded with the Americans to come in to the war on their side.  The first crack in isolation came in May of 1915 when the ocean liner Lusitania was torpedoed by a German Sub, killing 128 Americans. The level of attacks increased in 1917.

Sept 11 2001.  19 mostly Saudi terrorists hijacked 4 airliners and crashed 3 of them into US buildings: two into the World Trade Center towers in New York, 1 into the Pentagon in Arlington Virginia, and the fourth into a field in western Pennsylvania after passengers attempt to overpower the hijackers.  Roughly 3000 are killed in the attacks.  The CIA lead attacks into Afghanistan, where the hijackers had trained in the failed state there, but then president Bush redirected the military to attack Iraq, which had nothing to do with the hijackings and succeeding in turning it into a failed state too, killing at least 5000 Americans and hundreds of thousands of locals.

The Maine.  1898 The US Battleship Maine mysteriously exploded while at anchor in Havana Harbor, Cuba, which was a Spanish Colony at the time. The US went to war against Spain, eventually capturing Cuba, Puerto Rico, The Philippines, and more, despite no evidence whatsoever that anyone loyal to Spain was involved in causing the explosion.

Goldwater and the Gulf of Tonkin Incident Aug 1964.  Two months before the 1964 presidential election, two US ships on patrol in the Gulf of Tonkin near VietNam, where US "Advisors" were at work "fighting communism", reacted to something they thought they'd seen and began firing into the night.  In fact, there was nothing there but nerves, but the presidential challenger incorporated it into his campaign and the Viet Nam war began, killing 50,000 americans and at least a million south east asians, leaving Viet Nam just as communist but a lot more miserable than it would have been had we walked away in 1964.

The first 4 were real, serious acts of war by a foreign power meaning harm to America.  For three of those, America responded with all its strength, but the one I rank the third most serious in our history, we have done very little about.  American entry into WWI shortened the war, so it probably was the right thing to do, but that was only a good thing because the existing combatants had made it so horrible.  We responded as badly as we could have to Sept 11, making the situation that caused it immeasurably worse.  What we should have done is sent teachers to Afghanistan, and only enough troop to keep the teachers safe.  The Spanish and Mexican American wars, and the "Banana Wars", were pure colonial landgrabs, as were Vietnam, Korea and Iraq, although their goals were murkier and conflated with the nonsensical "anticommunist" and "antiterrorist" policies.

About the third attack:  We need to protect our elections.  We need to to protect our media.  We need to protect our judicial system.  We need to protect the international institutions that keep us safe.  The president and his toadies are attacking all of these.

Trampled Grass

A trophic cascade is an ecological situation where the introduction or removal of a predator near the top of the food chain causes population changes all through the food chain.   The case of interest to me is predators that chase large grazing animals.

Every continent except Antarctica has large, grazing animals, and many of the ecosystems within those continents.  Most tend to group together in large herds, which find a happy place to graze, until a predator attacks them, at which point they run and find a new happy grazing place.  The grasses they eat have developed in symbiosis with these grazing animals--it gets trampled and eaten, but the soil gets kicked around and a fresh supply of rich fertilizer gets left behind, as well as any fresh seeds that may have stuck to the grazers fur or survived the passage through its gut.  As long as the grazers don't spend too long, it's good for the grass.

We humans have interfered with this process.  Some grazers have been domesticated, and they stay in one place, often penned in, until the grass is gone, and then we provide them with hay or grain from some other place while they continue to destroy the land they are captive on.    In other places, we've removed the predator, which removes the incentive for the animals to move now and then.  An example is the mountain meadows of the rockies.  When there were wolves, the elk could only stay in the bottomlands for a short time, and the grass grew slowed the creek.  Beaver and other creatures came and made further changes, slowing the creek further and turning parts of it to wetlands, bringing even more diversity.  A classic trophic cascade.  Removing the wolves allowed the elk to eat all the grass in easiest place to get it, the bottomland, and the creek became a roaring stream and washed all of this away.   Restoring even a few wolves after they'd been gone for a century brought it all back.

I've been reading about Joel Salatin and Allan Savory.  They both come at this from a slightly different angle but they're saying the same thing.  Salatin has developed a method of raising cattle and chickens where fences in a small herd--100 or so--and moves them almost every day.  He sizes the pasture so that they consume most, but not quite all, of the best grass before he moves them.  A few days later, he hauls a henhouse to the same pasture, where the chickens pick over the manure.  He doesn't bring the cattle back until the grass is completely recovered, which happens pretty fast, because he didn't let cows graze too long.  He points out that any bovine parasites that the birds eat don't go any farther, and the same is true of chicken parasites that the cattle may eat, so the animals are much healthier than their relatives on farms nearby.   The grass is way healthier, and he says he gets more than 4 times the beef productivity for the same amount of land grazed the traditional way, and the eggs are essentially free.

Allan Savory has been trying to reverse desertification in Africa..  He tried reducing the trampling, including culling 40,000 elephants at one point, but that only exacerbated the desertification.  What has worked, very much to his surprise, was encouraging cattle herders to graze their animals temporarily.  Places where all the grass was gone but still had brush for the cattle to eat began to sprout grass a few days after the cattle left, and with each visit it became healthier.  The animals become healthier too.  The key is to not let the animals eat it all.  The herders are playing the role of the predator.  Perhaps, but maybe not, coincidentally, the herders have been finding that their animals are about 4 times as productive when they feed them this way, just as Joel Salatin has.

Grass and trees are the best way we have to reduce CO2 in the atmosphere.  The carbon that makes up these plants cells is entirely extracted from atmospheric CO2.   Monoculture agriculture is ruining our land, and making our crops, our animals and ourselves unhealthy.

Technical Errors in "The Martian"

Andy Weir's The Martian is one of the most technically accurate science fiction stories of all time, although it's not perfect.  I just re-watched the excellent movie, which followed the book unusually well.  This critique is based on the movie:

Martian atmosphere is about 1/10th that of earth.  The wind would not carry all that much energy, even if it's blowing 200mph, and it's hard to imagine it knocking over the MAV or carrying enough sand that the sand might do it.  The pictures of dust devils taken by the rovers are scrawny little things.  It is plausible that it might cause flight in lightweight things that aren't fastened down properly, such as satellite dishes, so the incident that seems to have killed Watney is remotely possible, but the crew would have simply hunkered down and ridden it out.

The Aries 4 MAV is already on Mars, 4 years ahead of its use.  Mission planners expect it to still be standing when the Aries 4 mission arrives, despite frequent sandstorms that apparently can knock a MAV over?

It is inconceivable that a month long surface mission wouldn't have several redundant transceivers that could quickly reestablish communication between a marooned spaceman and earth, even if the primary went back into space with the rest of the crew.  For example, I'd think each rover would have had a high gain antenna analogous to the one on Pathfinder--about a foot in diameter: a phased array with relatively low bandwidth and only needs to be aimed in the right general direction to obtain maximum gain.  Not quite enough bandwidth for SDTV video, adequate for voice, and more than adequate for TTY and still photography.

It doesn't make much sense to have a specialist botanist on an early Mars exploration mission.  A different specialty scientist who happened to have a background in botany, perhaps, but not a specialist.   Had I been in Andy Weir's place, I'd have had Watney have been a farm boy who grew up to be a scientist (geologist perhaps?) and astronaut.  Growing potatoes in martian soil and human manure is pretty basic farm stuff.   I'm pretty sure I could do it and I'm not a farm boy or botanist at all.

Watney manages to keep his potato harvest healthy for over a year after the breach, in the same atmosphere he's living in.  It's probably impossible to keep bacteria and fungus from his own body from infecting them.   I can't keep potatoes for more than a few months, unless I freeze them.    The originals from earth probably survived this way too: vacuum packed and frozen.  He'd have protected his harvest exactly this way, and they would have survived the HAB breach, and he could have started up his garden again.

The HAB is soft skinned.  This is plausible as a covering for non-human stuff and even short term habitation, but unless there is some sort of magic radiation shielding developed between now and then, totally implausible for a month long habitation.  The astronauts might survive, but probably not for long enough to make it home.  I think the only real answer is to put the dwelling underground.

The same point holds for the Hermes interplanetary ship.  They got a lot right for the Hermes design, but there's no evident shielding, which should probably be ten feet thick or more around crew areas.

A great deal of space on the Hermes is given to human-occupied areas in microgravity.  I would doubt there would be many--airlocks and docking berths--but you wouldn't expect the astronauts to need to go through them very often.

The calculations Rich Purnell needs to solve to work out the maneuver are mathematical and demand high precision, but are not especially complex.  He wouldn't need a supercomputer to solve them.  The laptop on his desk would be ample.  (had he been doing it in 1966, he might have needed a supercomputer, but the PC I'm using to type this is about 300 times faster than a CDC 6600, the fastest machine of 1966).   Even if he did need a supercomputer for some reason, he wouldn't have needed to leave his office to do it.  (that said: I met an "Orbits" guy when I worked at Lockheed Missiles and Space.  The eccentric Rich Purnell character is totally plausible.)

The MAVs (both Aries 3 and 4) are entered through an airlock in the middle of the floor.  Underneath that floor is the second stage of the ascent rocket and underneath that is the first stage.   Wrong.  The astronauts would climb up the MAV on the outside and enter through a door in the side.

When Watney enters the MAV with his EVA suit on, he enters through this same airlock door, and closes and fastens it.  It is obviously a big heavy thing.   I'd think it'd have been among the first things to be tossed overboard.

The nose cone is shown sliding right past the MAVs attitude control jets.  Watney is going to need those.  He'd have figured out some way to guarantee not breaking them.

I don't understand why they needed to blow the airlock door.  They can override other safeties, why not that one?   It does make a fun plot element though.

We see personal laptop computers from Commander Lewis, Johansen and Watney, and we can be sure the others left theirs behind too.  Why is it that only Lewis has recorded music on hers?


addenda:
Water has recently been discovered on Mars, trapped in rocks, plentiful and reasonably easy to obtain.  This spoils one of the central plot elements, although Weir couldn't have known that when he wrote the book.

I read Weir's latest, Artemis.  It's almost as good as The Martian.  

Slow Growth Policies

A lot of cities are struggling with unbalanced growth: some sections are getting intense gentrification and densification.  This unfortunately, is inevitable.  I happen to live in Seattle, so I'll use it as an example.

The symbol of Seattle densification is Amazon.com, which has built an urban campus in an area called South Lake Union--because it is south of a small lake called Lake Union.  The area used to be part of what was called "The Denny Regrade."  In the 1920s a steep hill named for city founder Arthur Denny, a little north of downtown, was sluiced down and the area leveled using hydraulic mining techniques.  It became an area of small industry and commercial buildings, cheap apartments, dive bars and other relatively low cost business. The Seattle Center, site of the 1962 Worlds Fair, was built on one part of it, and the largest freeway off and on ramps in the city passed through it, in a convoluted group of roads that came to be called "The Mercer Mess" after the biggest of the streets involved.  In the 1990s, a group led by Paul Allen began buying up properties with the goal of revitalizing one part of the Regrade and fixing the Mercer Mess.

The timing and location turned out to be perfect for Amazon, which moved its headquarters into SLU, and began to grow.  And grow.  And grow.   Tens of thousands of young professionals came to Seattle to work at Amazon.  City life suited them and they very quickly changed the dynamic of the area.  Where it had been a semi-suburban part of the city, where coming and going was all about the automobile, it suddenly became nearly impossible to find parking and very difficult to even get your car from one side to the other.  The Mercer Mess is symbolic: where it had been nominally 4 lanes in each direction with only a few traffic lights and pretty good access to the rest of the city, now it's 3 lanes in each direction with a traffic light every block and during rush hour, traffic is so dense it often takes more half an hour to get on to Mercer from a side street.  The Amazon workers resorted to moving within walking distance of work, and consequently there are dozens of new, expensive high rises within walking distance.

The people who were already here were screwed.  Thousands of people were kicked out of low rent housing, unable to find affordable housing within 20 miles or more of the area, which for most had also been where they worked.  Seattle is very much a car-focused region and city.  There are some symbolic transit systems, which do work, but their capacity is very low and the better ones cover very, very little of the region.  The bus system has better coverage, but it is terribly limited.  For example, the place I used to live in Redmond had service once an hour, from 6am to 7pm.  It was a half mile walk.  Heaven help a cripple, or someone carrying something big.  It had even shorter hours on weekends. 

The Seattle City Council wants to impose a "Head Tax" to employers over some threshold size.  I think there's the germ of a good idea in this, but the goal is mistaken.   They're trying to discourage big businesses from building downtown.   I think the right thing to do is to tax businesses to build transit.  Grade separated transit, so it can reduce congestion.  Long distance transit, so the people who want to work downtown can get to housing where it's affordable, and people who want to live downtown can get to businesses that are located where it's affordable.

What If Smallpox Hadn't Cleared America?

This map has been circulating
It purports to show what would have happened had Europeans never come to America.  It's not accurate; it's a projection by someone writing speculative history of what would have happened to the various native groups 500 years after Columbus.  It's completely bogus: Europeans did come to America, their way eased by Smallpox and other pestilence, and these borders are quite different than what they found.  The Europeans would have come to America eventually, no matter what happened.  The Vikings had come 500 years before Columbus, and there were lots of other explorers who would have found their way here sooner or later had Columbus somehow failed.  But it's an interesting question: what might have been different if Columbus and his peers had met with credible resistance?

In 1492, Europe had the most advanced civilizations in the world, but not by much.  China and the Middle Eastern civilizations had been more advanced only a century or so earlier, and there were at least two unrelated civilizations in America that were not far behind, too.  No doubt Europe was advancing faster than the rest, fostered by enlightened rejection of the authoritarianism and religious fundamentalism that had held them back for a millennium.

But Europe was able to overrun the New World, not by the sophistication of their technology, although that helped in some places, and certainly not because of their religion, but because they were preceded by devastating disease, especially smallpox, but probably also plague and others, which the first explorers had brought along with them.  The English settlers that arrived in Virginia and New England 120 years after Columbus were surprised to discover fallow agricultural land that had already been cleared and a native population that was willing to teach them how to farm it.   Cortez and Pizzaro, arriving a century earlier, were similarly able to exploit the political disruptions caused by the disease.

What would have happened had disease somehow not been so effective against the natives?  We have a few hints: The Vikings made a few incursions and were, in all but one case, driven back by the locals, who they called "Skraelings".  In the one exception, their settlement was in the northmost part of Newfoundland, where life was too hard for the natives, and the Vikings also gave up and went home after a few decades.  In the places that the natives had a few centuries after Columbus to recover, such west of the Appalachians, and especially the US great plains, the natives fought back pretty hard and it took a very big army to defeat them.

We can imagine a scenario where things had gone this way across the continent:  Cortez attacked Mexico barely 20 years into the devastation.  What if the timing had been different by a few decades and the Aztecs who had immunity to Smallpox had had a chance to repopulate?  Cortez would have met fierce resistance, and certainly wouldn't have been able to conquer so thoroughly.  Something more resembling what happened in India or China is a lot more likely: trading outposts supported by military would have left the existing civilization roughly intact, and European dominance would have needed to be more insidious and commercial in character.   The native civilizations would have been changed radically by the outsiders, but there would be a clear political and cultural lineage to this day, where in fact they were truncated--little pieces of their own culture merged into the dominant European one.  There would be plenty of Europeans in America, just as there are plenty of Asians and Africans in Europe, but something like the map above might have happened.

Emigration and Authoritarianism

Trump started his campaign with the astonishing statement that "They're not sending their best."  A few weeks ago he wondered why it's only shithole countries that send people here, why nobody from Norway?  Ignoring the obvious racism underlying both statements and many others, it expresses a deep misunderstanding of what emigration is.  People don't leave their home because some central authority is ordering them to (although there are a few exceptions: the Trail of Tears, Slavery of Africans, a few others).  Leaving home is traumatic.  You don't do it unless there's a pretty good reason.   The families of three of my four grandparents all came here because they believed it was likely that someone in the old country would kill them--not because they'd done anything wrong, but because of their ethnicity.  People leave the old country because there's a war happening, as presently in Syria and several Latin American countries, or because there's a famine or some other terrible circumstance.   A tiny fraction of people leave the old country even though they were doing ok in the old one because there's a terrific opportunity in the new one.  High tech "brain drain" is one of the few examples of this.   People aren't leaving Norway for a very simple reason:  Norway has one of the strongest economies in the world and has among the best social safety nets--so even if things aren't going so well for you, Norway is a good place to be.

The big excitement of the moment in anthropology is the discovery that rather than a single wave of emigration from Africa, there is clear evidence that there have been many waves of emigration that took place over many thousands of years.  There's even a little evidence that there may have been humans in America 130,000 years ago, ten times what had previously been thought.

I find myself astonished that anybody ever thought that there was a single wave.   The forces that drive emigration--famine, war, the search for a better opportunity--are driven by individuals, not by some central organizing force.  Africa is a big continent.  The first humans probably spread from wherever they evolved to somewhere nearby.  The grass may have been greener, hunting may have been better, another tribe or species was out competing them or killing them and they wanted to get away.  Before long, some group found their way to other continents.   Surely this happened thousands of times over a hundred thousand years.

Humans are naturally curious, and some humans are more curious than others.  The first Americans to explore the west were more curious about what lay over the next hill than they were hungry or desperate.  With very few exceptions, this was an internal thing. They had unquenchable wanderlust.  Even Lewis and Clark were doing it because they wanted to--the sponsorship made the trip easier.  The first explorers, 100,000 years ago or more, surely were the prehistoric version of James Bridger and Lewis and Clark.  It's easy to imagine some band, or possibly even an individual, driven by wanderlust or perhaps their raft was simply blown off course, finding their way to America, and unable to get back, or perhaps uninterested, making the best of it.  Most such bands died out, just as the 11th century Vikings who settled in Newfoundland did.  But a few made it.