An invisible region where intense gravitational fields bend all electromagnetic energy around it and drain power from anything inside, discovered in J'naii space in 2368.
Null space appears in the Next Generation episode The Outcast. The androgynous J'naii ask the Enterprise for help in finding a shuttle that has vanished without trace, and the search uncovers a pocket of null space, a phenomenon previously only predicted in theory.
Because light bends around it the pocket cannot be seen, and it rapidly drains the energy of any vessel that enters. William Riker and the J'naii pilot Soren map its edges and take the shuttlecraft Magellan inside.
They find the missing craft and beam its two crew aboard with almost no power left, and are themselves transported out by the Enterprise. The mission also brings Riker and Soren together, which leads to her prosecution for identifying as female.