Two Ships That Pass In The Night
October 20, 2014 9:44 AM   Subscribe

This is a picture of a comet heading for Mars. Mars is the big red thing and the comet, named C/2013 A1 ('Siding Spring'), is the green-tailed beast to the lower left.

The comet will pass within 80,000 mile of the surface of Mars, which is close enough (one-third of the separation between the moon and the Earth) that the sizable population of Martian robots need to think about potential damage from cometary debris. JPL has considered re-orienting some of the satellites, but many will use the opportunity to observe the comet as it goes by (full story).

Website of Damian Peach, astrophotographer who took the image in the first link.

Obligatory Phil Plait article with more details, and updates as we receive data from Mars.
posted by benito.strauss (26 comments total) 11 users marked this as a favorite
 
Oops, I forgot to link this NASA press release, which gets into the details of managing the martian satellites, and mentions some orbit-adjustment maneuvers that have already taken place.
posted by benito.strauss at 9:55 AM on October 20, 2014


Relative sizes and separation to scale, from Adolf Schaller. Mind boggling.
posted by RedOrGreen at 9:59 AM on October 20, 2014 [3 favorites]


False color image. Comets aren't green and nebulas aren't bursting with rainbow colors.
Astronomers like to treat the sky like a coloring book and there's no such thing as Santa Clause.
posted by Fupped Duck at 10:01 AM on October 20, 2014 [1 favorite]


And you can watch a live feed of which spacecraft the Deep Space Network is communicating with. There's going to be a lot of talking to Mars today.
posted by zamboni at 10:01 AM on October 20, 2014


"Earth at Risk" after only dedicated southern hemisphere comet spotting "early warning" facility shut down.
posted by Rumple at 10:06 AM on October 20, 2014 [1 favorite]


The Planetary Society roundup is also worth reading.
posted by zamboni at 10:07 AM on October 20, 2014


Mars is the big red thing

That's the problem with space science for us laymen - all this impenetrable jargon.

(Seriously though, thanks for the post. How amazing to have Martian robots that can watch this thing pass by.)
posted by sobarel at 10:20 AM on October 20, 2014 [6 favorites]


Relative sizes and separation to scale, from Adolf Schaller. -- @elakdawalla one suggestion. If he had put the earth mars distance for scale too, it'd give amazing perspective.

I worked it out. Earth would be about 121 feet to the left (for an average large desk monitor).
posted by crapmatic at 10:24 AM on October 20, 2014 [4 favorites]


I suddenly feel like listening to Progressive Rock.
posted by GuyZero at 10:24 AM on October 20, 2014 [5 favorites]


Tonight on CNN—On a special edition of The Situation Room: As fears about the deadly 'Siding Spring' Comet spread, Wolf Blitzer investigates the hidden dangers of space dust that scientists aren't telling you about.

Then: On an extra special edition of Anderson Cooper 360, Anderson goes behind the front lines at the European Space Agency to bring you an exclusive report about the shadowy foreign group and the motives behind its top secret excursions to the far reaches of the Universe.
Plus: What deadly secrets about the Time/Space Continuum are Americans being kept in the dark about?

And finally: On an extra, extra special edition of Erin Burnett Outfront, Erin brings you an exclusive interview with Bruce Willis where she asks the tough questions: Are we on the verge of a real-life Armageddon, and does he still keep in touch with Demi?
posted by Atom Eyes at 10:39 AM on October 20, 2014 [1 favorite]


... the sizable population of Martian robots need to think about potential damage ...

Have they come up with anything cogent, so far?
posted by iotic at 10:41 AM on October 20, 2014


Atom Eyes: "Tonight on CNN—"

Coming up: Sanjay Gupta asks, "Is Comet Siding Spring safe from Ebola? The answer? Probably."
posted by Rock Steady at 10:43 AM on October 20, 2014 [4 favorites]


I suddenly feel like listening to Progressive Rock.

echoes pt. 1 and pt. 2
posted by stinkfoot at 10:46 AM on October 20, 2014


That's actually a photo of the New Sun on its way to replacing our ancient, fading sun.
posted by NoMich at 10:52 AM on October 20, 2014 [1 favorite]


And you can watch a live feed of which spacecraft the Deep Space Network is communicating with.

As of right now (1247CDT, 1745UTC) Mars will rise in about an hour at Goldstone and is nearing the horizon at Madrid. Once Mars is high enough above the horizon (10 degrees or so) at Goldstone, they'll cut MAVEN and The Mars Reconnaissance Orbiter over to Goldstone (presumably, to the DSS-25 antenna, and Mars Oddyseey and Express will cut over to either DSS-26 or DSS-15, depending on how much more time is need for Dawn. At some point, Dawn and ACE will set at Goldstone and be picked up at Canberra.

For the next couple of days, the Mars Missions are pretty much going to be the priority for the DSS.
posted by eriko at 10:54 AM on October 20, 2014


One of the interesting things here will be the interaction between the cometary tail and the upper atmosphere of Mars. It doesn't take much to knock a few extra atoms or molecules up higher, and that will increase the drag on lower flying sats, like MRO and Maven.

India's Mars Orbiter Mission is in an highly elliptical orbit with periareon at 421km, which means it should be affected less, but the risk is higher for MOM, because if it is affected, they don't have much left in ΔV to raise the periareon. That lack of ΔV is why they're in such an elliptical orbit. This was brought on by having to use the PSLV booster instead of the planned GSLV, but a series of failures in 2010 left them a little leery of using the more powerful but apparently a bit explodey GSLV. But that made for a much more complicated trip to Mars and much less fuel after orbital insertion.
posted by eriko at 11:22 AM on October 20, 2014


the New Sun on its way to replacing our ancient, fading sun

Buried deep in the New Sun purchase agreement was a clause requiring us to fire off monthly "fusion maintenance fee" shipments of titanium in the general direction of the Orion Nebula. No grace period for late payments, either, so we better light a fire under FTL development or we'll be tromping out through the thick blanket layer in home-made cold suits for our buckets of air.
posted by CynicalKnight at 11:27 AM on October 20, 2014 [2 favorites]


I don't understand why this isn't called Comet McNaught.
posted by charlie don't surf at 11:49 AM on October 20, 2014


I don't understand why this isn't called Comet McNaught.

You're going to have to be a little more specific.

Solo, McNaught has discovered at least 44 long period and 26 short period comets. Add to that another 12 co-discoveries. “Comet McNaught” usually refers to C/2006 P1, aka The Great Comet of 2007, the brightest comet in over 40 years.
posted by zamboni at 12:49 PM on October 20, 2014


I don't understand why this isn't called Comet McNaught.

The answer is a bit complicated. Basically, up until a decade or so back, comets were generally discovered by diligent (often amateur) observers, but today it's mostly teams coordinating their efforts as a survey, which may mean the discovery is only possible to be confirmed thanks to data from two or more team members. Naming is therefore a tricky beast.
posted by dhartung at 1:50 PM on October 20, 2014


Buried deep in the New Sun purchase agreement was a clause requiring us to fire off monthly "fusion maintenance fee" shipments of titanium in the general direction of the Orion Nebula.

The Orion Syndicate are at it again, huh?
posted by marienbad at 3:34 PM on October 20, 2014


How much stuff is actually falling on Mars? If this were to pass "that" close to the Earth, would stuff be hitting my car (exaggeration for effect) or would the Earth atmosphere be absorbing most of the matter coming off the comet. I will take my answer offline.
posted by fluffycreature at 4:15 PM on October 20, 2014 [2 favorites]


GuyZero: I suddenly feel like listening to Progressive Rock.
Maybe some Jeff Wayne?
posted by ob1quixote at 4:59 PM on October 20, 2014


fluffycreature, they actually answered that question in the NASA press conference. Answer: nothing reaches the ground. It's all dust and small particles, and all burns up in the upper atmosphere.
posted by intermod at 7:50 PM on October 20, 2014


Solo, McNaught has discovered at least 44 long period and 26 short period comets.

If you want to get into systems of nomenclature, Comet McNaught indicates a much smaller class than a Comet Siding Spring. But Comet McNaught C/2013 A1 is far more satisfying than Comet Siding Spring C/2013 A1, since all men are mortal and fame is fleeting, but as an institution the observatory could continue perpetually.
posted by charlie don't surf at 7:54 PM on October 20, 2014


Comet Siding Spring C/2013 A1, since all men are mortal and fame is fleeting, but as an institution the observatory could continue perpetually

Sadly, with the current government funding priorities, Siding Spring might go before McNaught.
posted by bystander at 2:57 PM on October 21, 2014


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