Fred Whipple:  A note was sent to the Minor Planet Mailing list (MPML) yesterday from the Harvard-Smithsonian Center for Astrophysics (CfA) announcing that Fred Whipple died yesterday at age 97. Among other accomplishments in a career than shone like a comet, he was the discoverer of six comets, originated the “dirty snowball” comet concept, pioneered satellite tracking, and invented the Whipple shield used to protect spacecraft when flying through dust. See a CfA 28 June 2002 profile related to his part in the then coming but ultimately failed Contour comet mission. BBC has a report today.

Impact theory:  Southwest Research Institute has a news release dated 26 August (images) that appeared yesterday about “a theory

The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done

• News briefs Fred Whipple + impact theory
• Risk monitoring – JPL has removed 2004 QA22

<Sunday|Tomorrow> Report news >> here

About the publisher Space news links

for the ignition threshold for impact-generated fires,” saying that “impacts resulting in craters at least 85 kilometers wide can produce continental-scale fires, while impact craters more than 135 kilometers wide are needed to cause global-scale fires. . .  The Chicxulub impact event may have been the only known impact event to have caused wildfires around the globe. The Manicouagan (Canada) and Popigai (Russia) impact events, however, may have caused continental-scale fires.”

Risk monitoring 31 August

The Monday Daily Orbit Update MPEC (DOU) had no observations of objects with impact solutions and there was no other risk monitoring news. The Tuesday DOU has two sets of 2004 QA22 observations from Great Shefford Observatory in England spanning both sides of midnight both last night and the night before. Today JPL removed its impact solutions for this object, which it estimates to be about 10 meters/yards wide.

Note: The editor, who is traveling, would like to thank Stu Megan for tracking changes in listings related to risk monitoring to help insure continuity in A/CC's reporting during this time.