Planetary Hazards

Even planets which look habitable at first glance may harbor all sorts of nasty dangers which may ensnare the unwitting explorer or colonist; this is a list of some. Note that some hazards can be mutually exclusive with others, and a given world can easily have multiple.  

Anoxic Highlands

Significant areas of land are high enough that the partial pressure of oxygen is too low to support human life.  

Low CO2 Concentration

Carbon dioxide levels are too low to support Terran plant life.  

Low Oyxgen Concentration

Oxygen levels across the planet are too low for humans to breathe.  

Extreme Oxygen Concentration

Atmospheric oxygen levels are so high that human flesh is a fuel source for fires. Exercize EXTREME CAUTION around ignition sources!  

Dangerous Fauna

This world's ecology includes dangerous creatures which an unprepared visitor could fall prey to, such as genetically-resurrected dinosaurs.  

Feral Mechology

Autonomous robotic systems, once used for functions such as industry, terraforming, or warfare, have run amok and transformed into a mechanical ecosystem full of feral drones, some of which can be deadly.  

High CO2 Concentration

Levels of atmospheric carbon dioxide are high enough to cause deleterious effects in humans which range from fatigue and headaches to death.  

High Oyxgen Concentration

Oxygen levels in the atmosphere are above 25%, making fires easy to start and spread.  


High ocean temperatures and large open stretches of sea allow colossal hurricanes to form, striking land with winds fast enough to sweep away buildings.  

Industrial Pollution

Civilization on this planet did not see much need for environmental sustainability, resulting in an ecosystem contaminated with all sorts of toxic, mutagenic, and long-lasting pollutants. Don't raise children here!  

Orbital Debris Belts

Battles and/or pollution have shrouded orbital space in debris, rendering transit to the surface treacherous and safe orbits hard to clear.  


An alien civilization with technology beyond that of Stellar Compact space once occupied this planet. Who knows what secrets--and what dangers--they left behind?  

Resource Depletion

Most natural resources have been depleted by spendthrift industrial activity, rendering self-sufficiency difficult without imports or waste-scavenging technology.  

Radioactive Contamination

Nuclear warfare or poorly-run atomic technology was this planet's evil of choice, and the scars still tick Geiger counters even long after.  

Solar Flares

The star which this planet orbits periodically spits out giant flares which irradiate the surface, threatening unshielded life.  

Sulfide Blooms

This planet's oceans have large oxygen-depleted regions, perfect habitats for bacteria which produce deadly hydrogen sulfide gas. Occasionally a cloud of this will roll inland, lethal to anyone without proper filtering devices.  

Technological Ruins

An advanced technological civilization once existed here, and some of its ruins contain active devices such as power sources or defense systems capable of harming an insufficiently cautious explorer.  

Toxic Lowlands

Low-altitude regions of this world have an atmospheric pressure high enough to cause toxic partial pressures of carbon dioxide. Unprotected humans must avoid such areas.  

Tropical Death Zone

Wet-bulb temperature in the equatorial regions can reach above 35 degrees Celsius, the point at which the human body can no longer cool itself, leading to death from hyperthermia without cooling equipment such as a refridgerated suit.  

Unexploded Ordnance

Even warfare without WMDs can still be devastating; this planet has many regions covered in the detrius of conflicts past.

Articles under Planetary Hazards

Cover image: by Vertixico


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