Messier 6 and Comet
Siding Spring
From NASA’s Astronomy Picture of the Day
This looks like a near miss but
the greenish coma and tail of Comet Siding
Spring (C/2013 A1) are really 2,000 light-years or so away from the
stars of open cluster Messier
6.
They do appear close
together though, along the same line-of-sight in this gorgeous October 9th
skyscape toward the
constellation Scorpius.
Still, on Sunday,
October 19th this comet really will be involved in a near miss, passing within
only 139,500
kilometers of planet Mars.
That's about 10 times
closer than any known comet flyby of planet Earth, and nearly one third the
Earth-Moon distance.
While an impact with the
nucleus is not a threat the comet's dust, moving with a speed of about 56
kilometers per second relative to the Red Planet, and outskirts of its gaseous
coma could interact with the thin Martian atmosphere.
Of course, the comet's
close encounter will be followed intently by spacecraft in Martian
orbit and rovers on the surface.
