Photos: Gravity experiments in space


Crystals tend to grow bigger in microgravity

Source:  NASA

Crystals tend to grow bigger in microgravity

These cubes of the mineral zeolite show the difference between earth-bound crystal formation (left) and crystals grown in space (right).

That's because liquid-grown crystals feed on material dissolved in solution, leaving a less-dense liquid behind. On Earth, this liquid floats upwards, creating a convection current in experimental containers that introduces flaws and limits the size of crystals. The effect is virtually absent in microgravity.

Creating larger, purer crystals can reveal more about their basic structure and properties. Zeolite, for example, is full of microscopic pores that can be used to filter and store materials, such as hydrogen for use in future fuel cells.


The International Space Station may still be under construction, but microgravity research has been under way for decades. Here is a round-up of some of the most notable experiments.
View All Photo Stories