162 votes
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An Earth-like planet is found in another solar system. What are the top priorities after landing in order to create a self-sustaining colony?

Firstly, if you don't have the capabilities to construct a closed life support system, then you have no business trying to construct a colony many light years away, with no support and no backup and ...
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114 votes
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Is this alternate history plausible? (Hard Sci-Fi, Realistic History)

The story can be summed up as follows. Von Braun is captured by the Soviets, not the Americans. Failure to beat the Soviets to the Moon extends the Space Race. An extended Space Race means space ...
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103 votes

What could a self-sustaining lunar colony slowly lose that would ultimately prove fatal?

EDIT April 26, 2020 While searching through my answers for research related to another question I came across this answer. The irony that I wrote this one year ahead of the Coronavirus pandemic, which ...
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85 votes

Is it a forgone conclusion that any exo-bacteria discovered on an alien, albeit Earth-like planet will be deadly to human life?

Exo-bacteria is more likely to be harmless than harmful There are a couple assumptions that you're making that really aren't the case. To start with, microorganisms that our immune systems have no ...
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78 votes
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Is pregnancy in zero-g a barrier to long term space living?

Last time I looked into this I was amazed these experiments (mammalian conception to delivery in orbit) had not been done. I figured I just had not found it and so I dug in this time. For mammals, ...
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  • 284k
78 votes
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Why would a previously spacefaring civilization become unable to build another interstellar ship?

The simplest way is probably to leave them with a shortage of unobtainium. A substance named for obvious reasons, that happens to be required for the production of FTL drives. Perhaps the limited ...
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  • 114k
76 votes
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How would Martian and Earth societies synchronize themselves regarding time?

First off, the issue with relativity is solved. No kidding! Barycentric time (TCB) is a time scale that an atomic clock would perceive were it co-moving with the sun. This, of course, is a ...
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  • 130k
71 votes

Colonizing the galaxy by slow boating reality check

Is this a realistic way to colonize and explore the universe? No. Apart from problems with generational ships, which you'll find discussed on Worldbuilding SE in other questions, there is a ...
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66 votes

Would there be any reason to colonize the coastal regions of a lifeless Earth-like world?

Water has a high specific heat. Consequently, the more water that is near a place, the more even the temperatures are. Deserts are notoriously burning hot in the day and freezing at night, but even ...
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  • 22k
66 votes

Why do people still live on earthlike planets?

Stability Nothing beats the radiation shielding of 1,000 kilometers of magnetic field + 100 kilometers of air + (at night) 6,000 kilometers of water and rock. For heat, nothing beats 22 billion cubic ...
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63 votes

Why would a previously spacefaring civilization become unable to build another interstellar ship?

Their ship and her payload were designed as a colony expedition. They had not just asteroid mining craft, and seeds for hydroponics, and modular habitat sections, they also had the blueprints and ...
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62 votes
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Differences in mindset between people born in space and people born planetside

Claustrophobia vs Kenophobia If you are born on earth, you are more likely to develop claustrophobia due to having access to open spaces and enclosed spaces being more dangerous. But if you are in an ...
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61 votes
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If true interplanetary and interstellar travel were achieved, would the decreasing mass of the earth become a problem?

Earth is big.[citation needed] The mass of Earth is about $6 * 10^{24}$ kilograms. Not all of that mass is usable to make spaceships, of course, but let's just hand-wave that and look purely in terms ...
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60 votes
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How would someone hide an asteroid in the void of space so only they could find it?

The primary way to hide something in space is to make it uninteresting. Start with a boring asteroid, made out of silicate rock rather than metals or organic compounds that are worth mining, orbiting ...
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60 votes
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Would gas giants work as waste disposal sites?

What you suggest is possible, but the solution is a major problem, for larger reasons. We have sent probes to crash into Jupiter. It is physically possible to send waste into a gas giant. Just as it ...
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  • 20k
58 votes
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Preventing racism in space colonies

Any group of humans can, over time, develop a sense of "us" vs "them". Racism is only one type of this behavior. Even if all of your colonists were to be identical clones, the ...
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  • 2,670
57 votes

Where in the solar system is the most viable place to put my colonists, after Mars and Luna?

The Asteroid belt. It has similar requirements for life-support systems as the moon. With the additional need perhaps for some areas with simulated gravity. It is next closest in terms of energy ...
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  • 3,328
57 votes
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Colonizing the galaxy by slow boating reality check

Slow being a little less than half the speed of light, thanks to getting a very large boost as they start their journey. Slow down there! literally. At that speed it's not really a generation ship ...
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  • 26.2k
56 votes
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How would the water flow if you were to have a shower in centrifugal force equivalent to 1 g on a rotating space station?

As the water "falls" from shower head height towards the drain at the floor, it would be moving at a fixed velocity and be rotating slower than it should at the increased radius of the bottom of the ...
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  • 24.1k
53 votes

Why would a colony need to relocate?

This isn't our land anymore, kiddo. There was a time in the past your old grampa here would oversee all of those mining operations, from the Red Hills all the way to the Prima City. It was such a ...
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  • 7,433
51 votes

What could a self-sustaining lunar colony slowly lose that would ultimately prove fatal?

Materials exposed to vacuum for extended periods often become brittle and/or literally lose mass over time. Outgassing, cold-welding, decomposition of alloys back to their constituent materials, ...
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  • 5,723
51 votes

How could humans reach distant stars and still stay as a united government if you can't use faster than light travel

If you have only lightspeed communications and STL transport, any organization larger than a single star system (including close binaries etc.) will be more a matter of cooperation than of actual ...
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50 votes

After we drain the Sun and migrate, why would humanity find the Solar System important?

Good old tourism. Why people go visiting caves with painting on their walls, or ruins of ancient cities, even though they have much more comfortable houses? Because they are curious about their past ...
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  • 245k
49 votes
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Would there be any reason to colonize the coastal regions of a lifeless Earth-like world?

I can think of two reasons: Access to drinkable water. If the oceans are salty or dirty, the settlers might establish desalinisation and/or water purifying plant (assuming today's technological level)...
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  • 1,208
48 votes

If we can have "all the comforts of home" in space why would we settle planets?

If nothing else we would need planets for raw materials and therefore have at the very least mining colonies or penal camps. You can't produce metals, plastics and all the rest from nothing. Also ...
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  • 20.1k
47 votes

Creating Fictional Slavic Place Names

You will likely have an easier time if you pick a Slavic language that uses a Roman alphabet. Like Czech or Slovak (which are very similar to each other). Then you don't have to deal with the unknown ...
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46 votes
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How would I coordinate meetings with people on Mars?

The same way we do now. I work for a multinational company, with colleagues distributed across a dozen time zones. When I need to schedule a meeting with many people, I simply open Outlook, and look ...
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45 votes
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Resources to justify long-distance space mining missions

Antimatter. It's insanely expensive to produce artificially, with estimates of up to $62.5 trillion per gram of antihydrogen. Naturally occurring antimatter in any decent quantity would be beyond ...
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45 votes
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Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?

In the savannah of the universe, stars are the watering holes needed to sustain life, but full of predators and dangerous. Colonies are fixed targets, perhaps there are some hostile alien entities ...
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45 votes

Where would space habitats get their oxygen from?

According to this lovely image from NASA (article here), the source of onboard oxygen in current spacecraft is mainly water electrolysis. The hydrogen so produced is processed with carbon dioxide to ...
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