Horrocks also puts his energies into the…

Horrocks also puts his energies into the highly complex task of determining the Moon's orbit.

He correctly hypothesizes that the orbit is elliptical rather than circular, and he anticipates Isaac Newton in suggesting an influence on the orbit from the sun as well as the earth.

In the final months of his life he also makes detailed study of tides, in an attempt to explain the nature of lunar causation of tidal movements.

Having returned to Toxteth Park sometime in the summer of 1640, Horrrocks in January 1641 dies suddenly at the age of only twenty-two and from unknown causes.

The lunar crater Horrocks is named for him.