This episode of Dnews was proudly made possible by the all-new 2015 Subaru Legacy.
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Mars can breath a HUGE sigh of relief -- it WON’T get hit by a comet in October…
but I’m kinda sad that the Red Planet won’t take one for the Planetary Team.
Hi there, I’m Ian O’Neill, the space producer for Discovery News, and I’m going to talk
a little about a huge event that’s about to occur in interplanetary space not that
far from Earth.
Some of you may remember back in 1994 when Comet Shoemaker–Levy 9 was ripped to shreds
by Jupiter.
The huge comet drifted a little too close to the Solar System’s largest planet and
paid the ultimate price for messing with the its powerful tides -- it broke apart and then
rained down, each chunk exploding on impact in Jupiter’s thick upper atmosphere.
This was the first time in modern history that we were treated to a violent planetary
event that we could view up-close -- the Hubble Space Telescope was there to forensically
study each and every impact.
Then, last year, astronomers noticed another comet lining up for a planetary impact.
This time it wasn’t Jupiter in the crosshairs (and fortunately for us, it wasn’t Earth
either!), it was Mars.
There was a VERY REAL possibility that we’d witness the mother of all planetary impacts
on a neighboring rocky planet.
Comet C/2013 A1 (also known as Siding Spring) is a new comet that is making its inner solar
system pass after dropping from the outermost regions of the Solar System.
At first, astronomers thought it was going to hit, but after further observations of
the comet’s path, it became clear that the half-mile-wide lump of ice and rock would
miss…. but only just.
Siding Spring will make close approach with Mars at a distance of only 80,000 miles on
the 19th of October.
If you compare that with Earth, that’s only a THIRD OF THE WAY to the Moon!
As far as near misses go, this is danger-close.
The Mars encounter has even prompted NASA and the European Space Agency to re-route
their orbiting Mars missions so they will be hidden behind the planet when the comet
flies by, to avoid potential damage to the satellites by high-speed comet debris.
But that’s not to say a grand observation campaign isn’t planned -- as the comet approaches
and flies away, NASA’s Mars Reconnaissance Orbiter, for example, will turn its camera’s
gaze away from the planet and at the comet for a VERY intimate view of Siding Spring.
Even NASA’s Curiosity and Opportunity rovers will observe from the ground, possibly witnessing
a Martian meteor shower as the comet’s dust hits the atmosphere.
But, for me, I’m kinda sad that Comet Siding Spring WON’T hit Mars (sorry, rovers).
A comet that size hitting a planet with a thin atmosphere would create a BIG crater,
around 6 miles wide, unleashing an energy equivalent of 20 billion megatons of TNT.
That’s roughly A BILLION TIMES more powerful than the largest nuclear weapon ever detonated!
Not only would such an impact be valuable for understanding how large space impacts
affect rocky planets (like Earth), a fresh impact in Mars’ crust would be a smorgasbord
of science.
We could send a manned expedition to study freshly excavated Mars rock; we could study
the prebiotic chemicals that comets are known to contain; we could even look for past and
present microbial life in the layers of Mars rock!
Hell, if there was any chunks of comet ice left after impact, or fresh ice uncovered
BY the impact, our hypothetical Mars explorers could have a source of water!
In my view, it would catalyze a new era in Solar System exploration.
Well, maybe next time.
Now that you know what MIGHT have happened, are you a little disappointed Mars isn’t
getting slammed after all?
Let me know in the comments below and keep coming back for more DNews every day of the
week.