Page "Giotto (spacecraft)" Paragraph 16

Images showed Halley's nucleus to be a dark peanut-shaped body, 15 km long, 7 km to 10 km wide.

Only 10 % of the surface was active, with at least three outgassing jets seen on the sunlit side.

Analysis showed the comet formed 4. 5 x 10 < sup > 9 </ sup > years ago from volatiles ( mainly ice ) that had condensed onto interstellar dust particles.

It had remained practically unaltered since its formation.