Comet ISON, C/2012 S1 (ISON) At Perihelion Will Be Travelling 1/6 Slower Than Lovejoy, C/2011 W3, The ‘Great Comet of 2011’.
. by Anura Guruge
C/2011 W3 (Lovejoy), in December 2011, and C/1843 D1 (Great March comet), in February 1843, went within 0.00085 AU [80,000 miles] of the Sun’s surface – 644,000 miles closer than will ISON!
These rank among the closest non-destructive cometary flybys of the Sun.
As Lovejoy approached perihelion it was travelling at 400 miles/second or 1.44 million miles/hour, 0.2% the speed of light.