A

David

Darling

disk

In astronomy, the term "disk" may be applied to a flattened, circular region of gas, dust, and/or stars. It may refer to material surrounding a newly-formed star, material accreting onto a black hole or neutron star, or the large region of a spiral galaxy containing the spiral arms.

 

A disk is also the apparent circular shape of the Sun, a planet, or the Moon when seen in the sky or through a telescope.