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Interplanetary Experience
But instead of hitting the ocean, you should land in an overheating hot tub on a sinking cruise ship, sending it crashing through the floor into the burning engine room as the ship goes under.
Title text: But instead of hitting the ocean, you should land in an overheating hot tub on a sinking cruise ship, sending it crashing through the floor into the burning engine room as the ship goes under.


Ambox notice.png This explanation may be incomplete or incorrect: Table is fine but general explanation is missing.

Some people and organizations in preparation for future planetary exploration organize half-realistic experiments in human behavior on other planets, trying to emulate or mock up - often on low budget - the conditions in which future explorers are to live and work. For this purpose, they build mock-up bases, habitats etc. in places that look like other planets or have the environmental conditions somewhat similar to other celestial bodies' surfaces. They seek out desolate places like deserts or polar regions for this purpose.

In this comic Randall tries to identify places on Earth that actually have environmental conditions as close to the other worlds' ones as imaginably possible on Earth. Some of the places suggested by Randall are borderline-survivable for a human, but most will kill you extremely quickly without a lot of high-tech gear - whether through severe hypothermia, immolation, crushing, or whiplash from violent winds. Similarly, nowhere in the solar system outside Earth is even close to survivable - there is no planet or moon with a breathable atmosphere, or where the temperature stays within the human-tolerable range of roughly −20°C to 40°C (−5°F to 105°F, 250-310 K). The only place humans have so far ventured off-world is the Moon, and only during lunar morning while wearing thick pressurized spacesuits. Some, like Venus, may never be visitable by humans without either huge advances in material science or full-scale terraforming and some, like the centres of the gas giants, will probably never even be visited by robots.

Table of celestial bodies

Celestial bodies Place on Earth Explanation
PlutoMoon (night)
Mercury (night)
Mt. Everest at night The dwarf planet Pluto is a small icy rock so far away from the Sun that it practically makes no difference if it is day or night, the Sun is just the brightest star in the sky of Pluto's "day" side . But for both the Earth's Moon and Mercury (the innermost and smallest planet of the solar system it makes a huge difference, which is why there is both a day and a night experience mentioned for these two celestial bodies (see below). Although they are very much closer to the Sun than Pluto this makes no difference during their night time (when they face away from Sun). They are both relatively small, rocky bodies with practically no atmosphere and relatively slow rotation. Therefore their surfaces not illuminated by the Sun will cool down to very low temperatures (around -170 °C, -290 °F, 100 K), making their nighttime hemispheres desolate, dark and cold places. Randall proposes the summit of Mount Everest (the tallest mountain on Earth) as the place that will emulate the conditions most closely. It is a rocky, desolate and cold place. Even though it is not the coldest place on Earth, it is the highest point on land, therefore it has the lowest atmospheric pressure. It cannot be compared to the near-zero pressure and 100 Kelvins conditions on the aforementioned bodies, but it is as close as you can get on Earth. The top of Mt. Everest has an air pressure just 1/3 of what it is at sea level, and the oxygen levels are so low that they are barely survivable although a few people have reached the top without oxygen tanks, but others have died after losing their supply, making it as close as you can get on Earth to the near-vacuum found on these worlds.
Moon (day) Mt. Everest at noon under a tanning lamp As explained above, Mount Everest is as good emulation of the Moon surface at night as you can get. During the Moon's day, its surface gets about as much Sun's radiation as Earth at noon, because both bodies' distance from the Sun is almost the same. The Earth's atmosphere, however, stops most of the Sun's ultraviolet radiation. A tanning lamp is a device emitting mostly ultraviolet radiation for the purpose of artificial tanning; here it is used to augment the filtered Sun's radiation in an attempt to emulate Moon's daytime conditions better. Since the Moon does not have any atmosphere it is hard to discuss the temperature experienced on the Moon, but still the surface of the Moon reaches temperatures above waters boiling point (100°C or 212 °F) during the day with an average daytime temperature of the Moon at 107°C (224.6 °F). This effect will not be very well emulated on the tip of Mount Everest (or even in the hottest (non volcanic) places on Earth's surface that reaches 53.9°C (129°F) - see the what if? Flood Death Valley).
Mercury (day) A lava flow at a volcano at noon Mercury's surface never quite reaches lava temperatures (if it did, it would be molten), but it gets close. At noon, Mercury's equator reaches 420°C (800°F, 700 K). Lava is a liquid usually at temperatures from 700 to 1,200 °C (1,292 to 2,192 °F, 970 K to 1470 K)) but depending on what type of rock it's formed from, lava can erupt at temperatures as low as 500°C-600°C (930°F-1100°F, 770-870 K). Standing on a volcano on a partially solidified lava flow (which, it goes without saying, is incredibly dangerous) would expose you to similar temperatures. Near the poles, Mercury's surface temperature is always very low as the axial tilt is almost zero meaning that the poles do not get much direct sunlight and their temperature is constantly below −93 °C (−136 °F, 180 K).
Venus A heat-shrink wetsuit in a blast furnace The average surface temperature on Venus is around 470°C (870°F, 740 K), and the pressure is 92 bar (by comparison, pressure on earth is only about 1 bar). A blast furnace is a bit too hot - the blast itself is 900 °C to 1300 °C (1600 °F to 2300 °F), and they can reach 2000 °C - but either temperature is enough to kill you in seconds. As the blast furnace would emulate Venus temperature but not pressure, Randall proposes a daring volunteer shall wear a hypothetical heat-shrink wetsuit. A wetsuit is an elastic garment worn mostly over the whole body by swimmers, divers etc. Heat-shrink tubing is a tube made of a material that shrinks when heated, used to provide extra insulation and mechanical or environmental protection in electrical and electronics work - you put a length of tubing over your wire, connector, or a joint and heat it with hot air gun, making it shrink and crimp over your device. A hypothetical heat-shrink wetsuit worn while sitting in a blast furnace supposedly would shrink rapidly in the extreme temperature, extorting great pressure on your body, thus emulating Venus surface atmospheric pressure.
Mars Mt. Everest at sunset Again, thin atmosphere and very cold temperatures, but Mars's dusty, greenhouse-gas-containing atmosphere means it's not as cold as Mercury at night, nor as hot as the Moon during the day. The sunset will also make the sky reddish-purple, similar to the way the Martian sky often looks.
Titan Waist-deep in an outgassing Siberian swamp Titan is one of the promising worlds for life - given that its surface temperature is −180°C (−290°F, 95 K), that says a lot about how inhospitable the rest of the solar system is. The chemistry of the planet is interesting - there are lots of nitrogen compounds and hydrocarbons, and the atmosphere is mostly nitrogen and methane. Similar compounds are produced by rotting material in swamps, hence the comparison. One key difference though is that on Earth, swamps are mostly water. On Titan, they're liquid methane. Siberia also has some of the most extreme temperature differences on Earth, while Titan is just consistently cold. Randall is presumably referencing Siberia's Pole of Cold, the coldest point in the Northern hemisphere having reached −71.2 °C (−96.2 °F). Not quite Titan levels of cold, but certainly deadly enough.
Jupiter-Neptune Jumping from a high-altitude balloon over an Antarctic Ocean winter storm (title text: and landing in an overheating hot tub on a sinking cruise ship, sending it crashing through the floor into the burning engine room as the ship goes under.) Note that it is Jupiter to Neptune thus including also Saturn and Uranus. They are under one called gas giants for a reason. All the planets have stormy weather (Uranus is the least active, and Neptune is the most active) and a very dramatic temperature and pressure gradient. On the edge of the atmosphere, conditions aren't much different to space, but as you fall in, the temperature and pressure rapidly increases past freezing point (allowing clouds of ice and water), past boiling point, and up to thousands of degrees until you reach the core of superheated iron and nickel. Being inside a burning metal ship crushed by the water pressure of the deep ocean is the closest imaginable representation of the pressure, but in fact the cores of these planets are far, far more inhospitable than that - Jupiter is so hot and high-pressure that hydrogen becomes a metal.


[Caption above the panel:]
Where to go on Earth to get the Interplanetary Explorer Experience
[A chart with seven rows with celestial bodies on the left side of seven lines and a description on the right side. The first entry has three celestial bodies in two rows, the rest are in one row, although the last entry encompasses a list of planets. Four times the day/night side of the celestial bodies is mentioned in brackets.]
Pluto, Moon (night) Mt. Everest at night
Mercury (night)
Moon (day) Mt. Everest at noon under a tanning lamp
Mercury (day) A lava flow on a volcano at noon
Venus A heat-shrink wetsuit in a blast furnace
Mars Mt. Everest at sunset
Titan Waist-deep in an outgassing Siberian swamp
Jupiter-Neptune Jumping from a high-altitude balloon over an Antarctic Ocean winter storm

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