Earthlike world

Earthlike world
The Earth seen from Apollo 17, 7 December 1972 · NASA/Apollo 17 crew; taken by either Harrison Schmitt or Ron Evans, Public domain, Wikimedia Commons

Read off: Earth

Air you can almost breathe, liquid water, forests of something like trees: the world every colony ship is looking for, and the one that hides its dangers best. Its life grew on its own road, so the green may not be chlorophyll, the fruit may not be food and the microbes have never met a human. Its numbers are Earth's own, the only living world anyone has measured; everything else about it the crew will have to learn.

In figures

Gravity
1 g (Earth)
Day
24 h
Air pressure
1 bar
Air
78% nitrogen, 21% oxygen
Mean temperature
about 15 °C
Coldest
−89 °C (record)
Hottest
57 °C (record)
Radiation
2.4 mSv a year of natural background
Liquids
Liquid water over 71% of the surface
Light
Lit
Going
Slow

Hear it

Hazards

  • Alien microbes. Life that never met a human: most of it cannot touch our chemistry at all, but nobody knows which of it can. Quarantine, filters and patience decide who goes home. D&D 5e (House rule): House rule: a creature that breathes the open air or eats unscanned food makes a DC 12 Constitution saving throw at the end of the day; on a failure it has the Poisoned condition for 1d4 days. A creature that succeeds three days in a row is safe from this world's microbes.
  • Food that is not food. The fruit looks ripe, the fish looks fat, and none of it may be made of anything a human body can use. Some of it is poison; most of it simply does not feed. D&D 5e (House rule): House rule: foraging finds no food a human can live on unless a lab or a DC 18 Intelligence (Nature) check proves it. Living on it otherwise is Malnutrition: a creature that eats less than half its daily food makes a DC 10 Constitution save at the end of the day or gains 1 Exhaustion level.
  • Pollen season. Something blooms and the air turns gold with spores. Most of the crew sneeze; one or two cannot breathe at all without a filter. D&D 5e (House rule): House rule: during the bloom, each creature without a filter mask makes a DC 11 Constitution saving throw each morning; on a failure it has the Poisoned condition until the next morning.

What may happen

  1. Someone opens their visor for the first time. The air smells of something like cut grass and something like rust.
  2. At dusk the forest starts to sing, a sound no recording from home resembles.
  3. A tree heavy with fruit that smells sweet; the scanner cannot say whether it is food.
  4. Two moons rise together, and the tide in the bay runs higher than anyone expected.
  5. A herd of six-legged grazers crosses the clearing, utterly unafraid of people they have never seen.
  6. A survey beacon from an earlier expedition, overgrown with vines, still blinking.
  7. After forty days the quarantine is lifted. The crew steps outside in light masks instead of suits, and someone lies down in the grass-that-is-not-grass.
  8. A red rash climbs up someone’s wrist where a leaf brushed it. It itches like fire and looks like nothing in the medical database.
  9. Clouds of tiny fliers fill the air, and not one lands on a human. Whatever humans are, they do not smell like food to them.
  10. The forest is a deep purple-black, its leaves tuned to drink light that green ones would waste.
  11. Rain comes, and it smells of nothing anyone knows: no wet earth, only something sharp and sweet, like cut metal and honey.
  12. The colony drills a well, and the water comes up clear, cold and full of things the filters were never designed for.
  13. A child born at the colony shows the party the safe berries with total confidence. The medic is horrified.
  14. Bread left out overnight is untouched by mould. Nothing on this world knows how to rot it.
  15. The lab result comes back: the local sugars twist the other way from Earth’s. Eating them would fill a stomach and feed nobody.
  16. A thunderstorm rolls over the hills, and for once the sound and the flash are exactly as they were at home.
  17. The foundations of an earlier colony lie under the creepers: a dozen slabs, a rusted water tank and no word of what became of them.
  18. A trail beaten through the undergrowth by something heavy runs exactly where the party wants to go.
  19. At night the forest floor glows in slow blue waves, as if something were breathing under the leaves.
  20. A stream so clear and so empty of anything moving that it is hard to trust.
  21. A company prospector, a cheerful man named Dov, maps the valley for a timber licence and talks about the money it will bring.
  22. Every suit comes back covered in hooked burrs, and decontamination takes an hour of picking them off one by one.
  23. The sky is the blue of home, and for a moment that is enough to make a grown engineer cry.
  24. Somewhere in the forest a giant falls. The crash rolls on for whole seconds, and then every living thing goes silent.
  25. A small furred creature has followed the party since morning, always at the same distance, always watching the food packs.

Adventure hooks

  1. The first colonists ate the fruit; the second wave arrives to find them healthy, happy and unwilling to leave the forest.
  2. A survey beacon from an expedition that never existed is blinking in the hills.
  3. The company wants the native grazers cleared for farmland, and the biologist wants them protected.
  4. Everyone in the quarantine dome dreamed the same song last night.

Who and what is met

Each is an SRD stat block under another name, as game masters reskin them.

Other worlds

Cold desert world, Ice moon with a hidden ocean, Methane world, Hothouse world, Volcanic world, Airless world, Ocean world, Tidally locked world, Acid world, Jungle world, Swamp world

Sources

This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.

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