Fred Lawrence Whipple

Fred Lawrence Whipple (November 5, 1906 – August 30, 2004) was an American astronomer, who worked at the Harvard College Observatory for more than 70 years.

He joined Harvard College Observatory in 1931 and studied the trajectories of meteors, confirming that they originated within the Solar System rather than from interstellar space.

He also invented a "meteoroid bumper" or "Whipple shield", which protects spacecraft from impact by small particles by breaking them up.

During these years (in the early 1950s), he wrote a series of influential papers entitled A Comet Model, published in Astrophysical Journal.

The basic features of this hypothesis were later confirmed; however, the exact amount (and thus the importance) of ices in a comet is an active field of research, with most of the recently obtained data[6] pointing to a low contribution of ices to a comet's mass (dubbed the "icy dirtball" hypothesis).

Whipple in 1927