Tip of the iceberg

Tip of the iceberg is an Pre-Astro Terran expression that is used to describe a situation where there is only a hint or suggestion of a much larger or more complex issue or problem, much like an iceberg on Terra is mostly under the surface of the water with only about 10% of it's volume above it. The amount of an iceberg that is above water depends on the salinity of ocean where it is located.