Aether Sea planets are among the deadliest found in Frackin' Universe, with Hazard Levels ranging from VI-VIII. They most frequently orbit Black Stars. Aether Sea planets are characterized by an abundance of liquid Aether, with small islands interspersed throughout. All of the Tier 6 vanilla ores (Solarium, Ferozium, Aegisalt, and Violium) are plentiful on Aether Sea planets; they usually include moderate quantities of high-level Frackin' Universe ores, as well, including Corruption, Uranium Ore, Neptunium, Thorium Ore, and Penumbrite Ore. Aether Sea planets are also the only naturally occurring sources of Xithricite ore.
The aformentioned islands consist of black slime blocks (which are poisonous to the touch) and Aether Dust. The latter is very interesting: while it is affected by gravity like loose silt or gravel, it will only fall vertically. This means that falling Aether Dust produces pillars and mesas rather than mounds.
Acid Protection (either through Whitespine, an Acid Shield EPP, or various armor sets) is a requirement for exploring an Aether Sea planet, but the real environmental threat is the liquid Aether itself, which applies the Shadow Tainted debuff when touched. Shadow Tainted reduces visibility to near-zero, which makes responding to enemy threats or finding the valuable ores on the sea floor almost impossible. Pyreite Armor is the best early choice for exploring these planets, although Xithricite Armor also provides immunity to Shadow Tainted. For very late-game players, the Shoggoth Armor acquired from the Frozen Wastes features immunity to the Shadow Tainted debuff.
In addition, players should also bring poison protection to protect them from the abundant black slime blocks.