This letter to the STARDUST
project was received from Fred Whipple. Dr. Whipple
is the originator of the "dirty snowball"
theory for comets, and has also discovered a few
comets himself. The Whipple Shields that the STARDUST
spacecraft carries were named in his honor.
The Whipple Shields protected the spacecraft
when it encountered Comet Wild 2 in 2004.
This letter was enscribed onto
that the STARDUST spacecraft carried
to Comet Wild 2.
Center For Astrophysics
Cambridge, Massachusetts, USA
November 25, 1997
To all Space Buffs:
Comets have long been an unexplored wasteland.
Today we know
that they are black and cold, consisting of ices
and dust that coalesced
from an interstellar cloud as it collapsed to
form the solar system.
Their physical structure is poorly known. Some
that comets have low densities, perhaps less than
half that of water
ice. This material would be crushable in one's
hands. Even the
ratio of ices to dust remains a subject of uncertainty.
physical structure varies over small distances
such as a few meters.
May Stardust tame comets to become terra cognita,
structure and isotopic composition!!
Fred L. Whipple
See also a letter from Paul Wild
November 26, 2003