Unknown

Unknown is an extremely dangerous planet (2-5 environmental hazards, some can be mildly annoying, some are deadly/irresistable). It is composed of randomly chosen biomes (both on the surface and underground), and can have almost any biome in the game (except Aether World biomes, etc.). It is more diverse than other randomized planets (Shadow and Super Dense), and can be of tier 7-10. Occasionally, these planets are host to a "false surface" in the form of a Lost World underground where things appear to be the surface but are, in actuality, a massive subterranean realm. It is wise to bring an Escape Teleporter to any visit to these biomes.


 * Outputs of Atmospheric Condenser on this planet are the same as on normal planets (Garden, Eden, etc.), regardless of the primary biome.
 * All species of bees have normal production (no bonus/penalty for biome).

Environmental hazards
All Unknown planets have different hazards. For each planet that you visit, its hazards are revealed when you land on it for the first time.
 * The number of hazards is chosen randomly (2-5). The higher is the planet tier, the greater is the chance of getting more hazards.
 * Severity of hazards (e.g. Mild Cold vs. Extreme Cold) doesn't depend on planet tier.
 * Only 1 hazard can be chosen from each category (for example, Mild Cold and Extreme Cold are in "cold" category, so a planet can't have both of them at the same time).
 * Some Unknown-only hazards are not blocked by direct immunities. For example, Lethal Cold is not blocked by "Immune to Extreme Cold".
 * They can, however, be blocked by having high resistances (e.g. 80% Cold resistance gives immunity to Lethal Cold).
 * Unknown-only hazard "Overwhelmingly Maddening Atmosphere" can be blocked with 80% Mental Resistance.
 * Some uncommon hazards like  (Intoxicated) and   (Bee Stings) can be blocked by Immunization medical buff (from medical space stations).

Temporal Instability
"Temporal Instability" hazard is unique to Unknown planets. It causes your health/energy/hunger/location to sometimes return to where these values were N seconds ago. Various minor stats (shield health, energy regen cooldown, etc.) are also affected.

There is no immunity to it. Depending on the situation, it may be to your tactical benefit (getting you out of danger, healing you after a major fight, etc.). The downside is that you can't know when it would happen (unlike when drinking Timewinder Schnapps), so it can, for example, return your hunger to "almost starving" shortly after you have eaten.

List of all possible hazards
These are internal IDs of hazards (e.g.  is Mild Cold and   is Extreme Cold).

Strategy

 * If some Unknown planet is too harsh, and its hazards are too inconvenient, there is no shame in looking for another Unknown planet (it will have different hazards).
 * Most direct way to negate multiple hazards is to have your armor counter some of these hazards, use an EPP against other hazards, and EPP augment for whatever is left uncovered. Because many armors grant immunity to 2-3 hazards, it will likely be possible to ignore all 5 hazards completely.
 * There are many immunity-giving crops in the game (see List of foods): Blizzberry against cold, Lumivine against Pressure, etc. Nothing prevents you from eating them periodically to counter hazards. This allows you to wear whatever armor you want.
 * Mild hazards like Desert Heat or Intoxicated can probably be suffered through (they are not deadly, so there isn't a pressing necessity to have full immunity to them).
 * If your intention is to build a base on Unknown planet, you can place an Atmospheric Regulator (with augments for anything that Regulator doesn't counter out-of-the-box) to make this planet safe for future visitations. It can be used for initial exploration too, but its range is only 500 blocks, so you may need to move it periodically. and it needs to be wired to a reactor capable of powering it.
 * You can remove all hazards by terraforming the Unknown planet to another planet type. The difficulty is acquiring the terraformer (a tier 6 device) and staying alive on this Unknown planet until the terraformer completes its task.