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  • There's a lot of talk about sending humans to Mars.

  • But no one talks about Venus.

  • Why not?

  • And could Venus actually be the better option

  • for a human colony?

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  • Going to Mars has been a fixture in

  • our collective cultural consciousness

  • for a very long time.

  • It's inspired more sci-fi movies and stories than I can count,

  • a ride at Disney World, and a Twitter following for the Mars

  • Rover that's almost two million strong.

  • Meanwhile, Venus has inspired-- what?

  • Two Ray Bradbury stories, a plant

  • that eats flies, and a razor?

  • Basically, Venus has the worst public relations

  • team in the solar system.

  • And that hurts our sister planet,

  • not just in culture and media but in space policy.

  • Presidents Bush and Obama and the Chinese government

  • have all outlined goals for manned missions to Mars.

  • The Dutch nonprofit group Mars One

  • even held in international competition

  • to find volunteers for a one-way mission to the Martian surface.

  • But Venus?

  • No manned mission love-- at all.

  • Which is odd since in most respects,

  • Venus is actually an easier and less costly

  • colonization target than Mars is.

  • For starters, Venus is closer to Earth.

  • That's why we sent probes to Venus long before we sent them

  • to Mars and why we sent more of them.

  • Depending on the launch window, the round trip

  • can be 30% to 50% shorter, which is a major factor

  • for manned missions.

  • Shorter trips means less weightlessness and radiation,

  • less food and water to carry, and thus

  • less fuel and lower cost.

  • This would also be a huge advantage

  • in moving the people and equipment necessary to actually

  • colonize another world, because bear in mind,

  • there's no Craigslist in space.

  • If we ever start a colony, we'll need to bring along

  • almost everything.

  • And it's not just the shorter trip.

  • The planet itself has some significant advantages

  • over Mars.

  • It's closer to the sun, which means about four times

  • more available solar power then you have on Mars.

  • It also has a thick atmosphere, unlike that wispy layer

  • on Mars.

  • That means better protection from space radiation

  • and meteorites for our enterprising colonizers

  • and their future cities.

  • It also means more available carbon dioxide

  • from which, in principle, you might extract oxygen.

  • But the real kicker is gravity.

  • Venus has about 0.9 Earth g's-- pretty close--

  • while Mars has less than 0.4.

  • And one thing we do know is that prolonged low gravity

  • is bad for humans.

  • How bad?

  • In Earth orbit, astronauts lose bone mass

  • at about 10 times the rate of someone

  • with advanced osteoporosis.

  • Now no one knows exactly how bad Martian gravity

  • would be for humans, but it's definitely not

  • going to be good.

  • On Venus, that's far less of a concern.

  • And remember, we're talking about long-term colonization,

  • not just visits.

  • Even if we have the technological means

  • to add water to a planet's surface and oxygen to its air,

  • changing the planet's surface gravity

  • is currently not even within the realm of discussion.

  • So terraforming seems silly, and if people couldn't live there

  • more than a few months without their bones falling apart.

  • A theoretical Venutian colony thus

  • seems to have a lot going for it.

  • So why then this tunnel vision for Mars?

  • Surfacism.

  • OK, I just made that word up, but hear me out.

  • Ever since the days of seafaring exploration,

  • we've had an obsession with landing

  • on the surface of things.

  • If you don't plant a flag on something,

  • it's almost like having gotten there doesn't count.

  • So what's all this have to do with Venus, which

  • actually has a solid surface?

  • Well it does, but humans can't land on it.

  • See, there's a teensy problem with temperature.

  • There's so much CO2 on Venus that the greenhouse effect

  • makes the surface hotter than hell-- over 450 degrees

  • Celsius, well above the melting point of lead.

  • But the bigger problem is the barometric pressure

  • on the surface.

  • It's over 90 Earth's atmospheres.

  • That means that landing on the Venutian surface

  • would be like diving one kilometer underwater on Earth--

  • far beyond the crush depth of most military submarines.

  • In fact, most probes that NASA and the Soviets

  • sent to the surface of Venus imploded in midair.

  • We learned our lesson and a few reinforced probes

  • did manage to touch down and send images of the Venetian

  • surface.

  • But even those only lasted about two hours

  • before-- [SOUND OF AN IMPLOSION] --you know.

  • The point is-- I think surfacism is a real bias.

  • And the fact that we can't live on the Venutian surface

  • could help explain why Mars gets all the hype.

  • But maybe that's sensible.

  • I mean, if a surface will kill us,

  • there's no point in going there, right?

  • Not so fast.

  • See, around 50 kilometers or 30 miles

  • above the Venutian surface, some interesting things happen.

  • First, the temperature drops to only about 70 degrees Celsius.

  • That's still super hot, but firefighting equipment on Earth

  • can withstand proximity to forest fires with temperatures

  • that reach over 2,000 degrees Celsius.

  • The pressure at that altitude also

  • dropped to almost exactly one Earth atmosphere.

  • That means humans would need heat-resistant clothing

  • and oxygen masks, but not spacesuits to walk around

  • in that environment.

  • Granted, there's the minor nuisance

  • of sulfuric acid floating around in the Venutian air,

  • but that's potentially manageable.

  • And at that altitude, the atmosphere

  • is still dense enough for lots of stuff

  • to floae-- like balloons filled with helium

  • or maybe filled even with just regular Earth air.

  • Throw in the favorable gravity, and it

  • starts to look like the upper atmosphere of Venus

  • might be the closest thing in the solar system

  • to an Earth-like environment.

  • So it might make sense to colonize

  • Venus with cloud cities.

  • I am not making this up.

  • NASA Systems Analysis and Concepts Directorate

  • has unveiled a conceptual blueprint for this scheme.

  • They call it the High Altitude Venus Operational

  • Concept or HAVOC-- interesting branding choice,

  • but still super awesome.

  • We've linked the NASA videos in the description.

  • You should check them out.

  • Now for the record, this is all still conceptual.

  • We are very far from sending this guy

  • to lead our Venutian Cloud City.

  • But NASA is taking the idea seriously.

  • Right now, most of the chatter is still

  • about using Venus as practice for colonies

  • elsewhere-- like Mars.

  • So we haven't overcome surfacism just yet.

  • But this might change.

  • The gravity issue alone might make Venus the go-to option

  • for long-term human habitation.

  • Who know?

  • Centuries from now, if we learn how

  • to sequester enough carbon out of its atmosphere,

  • we might even be able to plant a flag or two.

  • So what do you guys think?

  • Is Venus a better colonization option than Mars?

  • Put your $0.02 in the comments-- or even better, tweet them,

  • #occupyvenus.

  • If we start a grassroots movement,

  • I'll let you know on the next episode of "Space Time".

  • Last week, we asked how you measure

  • the size of the universe?

  • Here are some of your questions.

  • awtizme asked, how can space be expanding faster

  • than light if the speed of light is the ultimate speed limit?

  • I'm going to answer you in two parts.

  • First, the speed of light speed limit

  • is for things moving through space, not about expansion

  • of space itself.

  • The second, you're right.

  • I shouldn't be talking about space

  • expanding at a given speed.

  • I should be talking about the size of the enlarge setting

  • on a photocopier button.

  • If I hit enlarge once every second,

  • then there will always be two points on the page

  • that-- if they're far enough apart to begin with--

  • will end up more than one extra light second apart after I

  • hit that photocopier button.

  • lingwingzing commented that this was a pretty intuitive way

  • to understand inflation.

  • Thanks for the compliment, but be careful.

  • We're talking about expansion of space in general.

  • Inflation refers to a very specific expansion

  • of space that occurred in just the first few instances

  • after The Big Bang.

  • The Mattman1313 says that the Hubble Bubble

  • is a possible alternative to the idea

  • that space is expanding at all.

  • That's not correct.

  • Space is expanding-- period.

  • What the Hubble Bubble offers is a potential alternative

  • to the currently observed, accelerated expansion of space.

  • Look it up.

  • And to Brandon Spears, sure, we could always

  • use help here at "Space Time".

  • Like the Hubble Space Telescope, we've

  • got schmutz on our lens too, so give it a wipe and help us out.

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