Comet C/2013 A1 possible Mars Strike in 2014

[Scopie]

Would be interesting if it hit Phobos- I think that would shatter the moon...

A recently discovered comet will make an uncomfortably close planetary flyby next year — but this time it’s not Earth that’s in the crosshairs.
According to preliminary orbital prediction models, comet C/2013 A1 will buzz by Mars on Oct. 19, 2014. The icy interloper is thought to originate from the Oort Cloud — a hypothetical region surrounding the solar system containing countless billions of cometary nuclei that were outcast from the primordial solar system billions of years ago.
We know that comets have hit the planets before (re: the massive Comet Shoemaker–Levy 9 (http://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9) that crashed into Jupiter in 1994), Mars in particular.

C/2013 A1 was discovered by ace comet-hunter Robert McNaught at the Siding Spring Observatory (http://news.discovery.com/space/astronomy/australia-wildfire-observatory-siding-spring-130114.htm) in New South Wales, Australia, on Jan. 3. When the discovery was made, astronomers at the Catalina Sky Survey (http://www.lpl.arizona.edu/css/) in Arizona looked back over their observations to find “prerecovery” images of the comet dating back to Dec. 8, 2012. These observations placed the orbital trajectory of comet C/2013 A1 through Mars orbit on Oct. 19, 2014 (http://astroblogger.blogspot.com.au/2013/02/will-comet-c2013-a1-siding-spring-hit.html).
Could the Red Planet be in for a potentially huge impact next year? Will Mars rovers Curiosity and Opportunity be in danger of becoming scrap metal?
It seems the likelihood of an awesome planetary impact is low — for now.

According to NASA’s Jet Propulsion Laboratory (http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013A1;cad=1#cad) (JPL) calculations, close approach data suggests the comet is most likely to make a close pass of 0.0007 AU (that’s approximately 63,000 miles from the Martian surface). However, there’s one huge caveat.
Due to uncertainties in the observations — the comet has only been observed for 74 days (so far), so it’s difficult for astronomers to forecast the comet’s precise location in 20 months time — comet C/2013 A1 may fly past at a very safe distance of 0.008 AU (650,000 miles). But to the other extreme, its orbital pass could put Mars directly in its path. At time of Mars close approach (or impact), the comet will be barreling along at a breakneck speed of 35 miles per second (126,000 miles per hour). (~55km/s relative to Mars)
Also, we don’t yet know how big comet C/2013 A1 is, but comets typically aren’t small. If it did hit, the impact could be a huge, global event. But the comet’s likely location in 2014 is also highly uncertain, so this is by no means a “sure thing” for Mars impact (Curiosity, you can relax, for now).

A flyby of that distance will mean that should C3/2013 A1 erupt with a tail and coma around its nucleus (as it becomes heated by solar radiation), our Mars rovers and orbiting armada of planetary observation satellites will have a very intimate view of this historic moment. It has the potential to be a more impressive sight than Comet ISON’s inner-solar system trek (http://news.discovery.com/space/asteroids-meteors-meteorites/nasa-probe-spies-incoming-comet-130206.htm) later this year. But understanding the nature of comets is hard to predict; we won’t know if the sun’s heating will be sufficient enough for the comet nucleus to erupt and start out-gassing for some time to come.

[Rob_K]

I just ran it through the orbit simulator in the JPL Small Body Database Browser and the results are disturbing to say the least. :scared2:

Cheers -

[JB80]

Ooh, I have never seen the simulator do that before.
Very interesting to say the least. I would expect chance of impact to gradually reduce over time as they track it but still you never know.

[Rob_K]

Sorry Jarrod, my feeble attempt at humour. The simulator never does that, I blame idle hands and Photoshop... :whistle:

Cheers -

[Scopie]

Its interesting though- the other orbital sims I have seen show the comet not traveling in the ecliptic plane but coming up from beneath it- perhaps its just a trick of perspective.

That doesn't make sense when some of the articles talk of a "head on" collision with the velocities of Mars and the comet combining to make the impact velocity of 55km/s. You know what these things are like- the media rarely gets it right, and space is large. Still if it did hit- what a show! Here's hoping Mars is on our nightside IF that happens- (goes to look up starry night for Oct 19th 2014)....

I also did some calcs looking at a potential Phobos impact. Real back of the envelop stuff considering we have no real idea how big the comet is. I put it at 2km diameter and mass equivalent of solid ice (Halley and Shoemaker-Levy (prior to break-up) are/were supposedly around 10-11km)- impacting on Phobos which is 11km dia and almost twice as dense as solid ice. Phobos is already supposed to have been weakened by the massive impact that formed Stickney crater. I feel fairly confident Phobos wouldn't survive a 55km/s impact with C/2013 A1. I'd love to hear from someone else who can do the arithmetic better though! If you do it as an inelastic collision, C/2013 A1 won't impart a whole lot of delta-v to Phobos, but Phobos as shrapnel would be another story entirely. We would get rings around Mars a whole lot sooner than the current forecast!

If we did get a collision I wonder if covering that big-a$$ sky would get a lot more funding. Diverting something with that much mass traveling that fast would be pretty hard to achieve in 18 months- that's 18 months INCLUDING the time taken for your equipment to be built and sent there. We've already seen some more money tipped in to detection following the pebble that blew up over Siberia last week.

As a footnote, Purdue university has a neat calc webpage (I've seen a better one somewhere else but the venerable Ron Baalke contributed to this one) that will tell you the effects of an impact on the Earth depending on how far you are from it and what it hits (crystalline or sedimentary rock, ocean strike etc.) For a 2km comet traveling that fast it's pretty interesting! You'd want to be more than 500km away and more than 100m above sea level.

[Rob_K]

Hi Brad - it's a 2-dimensional rendition and doesn't show perspective, so you can't tell from that whether the orbit's in the ecliptic plane or any other plane for that matter (other than the colour clue of the two shades of blue representing above & below the ecliptic). It's different in the database browser where you can toggle it around to get the perspective. :thumbsup:

Cheers -

[Steffen]

Damn, I hope it misses. An impact (esp a collision with Phobos) could send debris right into our path.

Cheers
Steffen.

[Scopie]

@ROB_K - try here, you can tilt and pan...

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=C%2F2013%20A1;orb=1;c ov=0;log=0;cad=1#orb

[Rob_K]

:shrug: That's where I got the frames from - re-read my post, that's what I was saying to you. You indicated that my animation showed the orbit in the ecliptic plane while as presented it doesn't show it in any plane at all. Other than the flat plane of each frame I suppose... ;)

Cheers -

[Limax7]

Nice info! I calculate orbit for this comet and it will reach -7.8 mag !!! from Mars and distance 118 370 km from Mars center at 19 Oct. 2014 at 21:12 UTC

Comet is big.

[gaa_ian]

Well this thread has hit the bigtime !
It is now featured on Universetoday (http://www.universetoday.com/100298/is-a-comet-on-a-collision-course-with-mars/)
Seems to me we are getting an increasing number of comets coming our way, makes me wonder ?

[Scopie]

Yep, and I see they put a the size of the comet way, way larger than my measly 2km. If it is that big and it hits anything I'd imagine that would be pretty spectacular. Still, there is an awful lot of empty space within the current error margin. Hopes are not very high yet. Imagine the research you could do examining the results of such an impact.

[OICURMT]

So is therer any speculation about Mars' gravity altering the path to the point where it may place move into a more regular orbit (or dare I ask... a NEO / doomsday orbit) ?

Hey.. all those people carrying cardboard signs need something new to write... ha ha

[mithrandir]

With a fairly recent ephemeris, Starry Night's idea of what C/2013 A1 will look like from Planum Australe, Mars (about 80S 155W) 2014-10-20 05:54 UTC. Range 935409km. Apparent mag -3.54.

[Joshua Bunn]

Here's a screen shot from TheSkyX of mars and the comet on 19 October 2014. Separated by 3 arc min. (obviously not the real separation)

Josh

[carl37]

Further developments:

http://spaceobs.org/en/2013/02/27/new-data-concerning-the-close-approach-of-comet-c2013-a1-to-mars/

It's getting very interesting!!

[ZeroID]

Interesting indeed !
Maybe Curiousity with all it's cameras can take a few pix as it slides by. NASA must be having a few conniptions about both the opportunitiy and the dangers to their hardware. If it's as big as they are speculating how visible will it be from here and how close will it pass us by ?
Could be rather spectacular whatever happens.

[carl37]

It won't pass very close to us Brent - it will be way south of the Earth's orbital plane when it passes us. It also doesn't get very close to the sun so it probably won't be super bright either.

[Scopie]

According to this website, Mars will be visible pretty much only during the day from Australia in October 2014.

http://museumvictoria.com.au/planetarium/discoverycentre/rise-and-set-times/?CBT=5&StartDate=19-Oct-2014

[mithrandir]

I tried generating a 3D plot with gnuplot from JPL ephemeris for the two. This is the closest they appear to get. They cross at close to 90° - Mars moving in RA, C/2013 A1 moving in Dec.

Z is in AU from the Sun.

[carl37]

That's a very cool graphic Andrew - I like it!

That looks about right using the MPC/JPL ephemeris, but my link a few posts ago is to a blog post by Leonid Elenin in which he states he has made new calculations including a further 6 days of observation arc.

These have not been published at the MPC yet, which is where the JPL data comes from.

Carl

[Scopie]

Iceinspace also noted on news.com.au

http://www.news.com.au/technology/comet-c2013-siding-spring-might-hit-mars-in-2014/story-e6frfro0-1226587784458

[rustigsmed]

This is very interesting, could either be spectacular for the rovers on mars or destructive. I wonder if the event would be visible from earth?
A collision you'd think would pump some more funding into the system!

[mithrandir]

Carl,

from JPL I get:

EC= 1.000076483324882E+00 QR= 1.399572296215722E+00 IN= 1.290158988346881E+02
OM= 3.009529751244577E+02 W = 2.438725831780988E+00 Tp= 2456956.205760196317
Using find_orb with all the observations in MPEC (last entries are in K13D50) I get mag 5.9 and:

EC= 1.0001012017 QR= 1.3995560557 IN= 129.01549809
OM= 300.95223725 W = 2.43718722 Tp= 2456956.189119
From 133 observations 2012 Dec. 8-2013 Feb. 20; RMS error 0.519 arcseconds.

Unfortunately find_orb won't generate an ephemeris with the necessary number of digits of precision to generate the graph. Trying those MPEC numbers in Starry Night it generates closest approach at 2014-10-19 23:21 UTC and 348526 km.

[Forgey]

Lets hope it doesn't impact, wow what a sight it would be to see observing it from mars :)

[wowlfie]

The Comet is estimated at 30 miles in diameter based on it's luminosity index ("absolute magnitude of the nucleus M2 = 10.3, which might indicate the diameter up to 50 kilometers [30 miles], the energy of impact might reach the equivalent of staggering 2×10^10 megatons!"; source http://science.nbcnews.com/_news/2013/02/26/17107085-comet-just-might-hit-mars-in-2014?lite

This Comet if it impacted Mars would be nothing short of astounding and could cause substantial damage on Earth from a swarm of Martians chunks thrown out of orbit. The energy of a collision is estimated to be 400 times larger than the one which did in the dinosaurs on Earth 65 million years ago (based on a mass of 125 times larger from it's volume and speed which is 3.2 times larger; 126,000 mph versus 40,000 mph estimated for the dino killer).

This would create a layer of Dust on Mars so thick that navigating would be all but impossible by robotic surveyors in the future.

It also has the capability of literally splitting Mars into pieces because Mars has little atmosphere to heat up the comet and destroy it before it impacts-so it will dig a huge hole many miles deep and throw an immense amount of material out into space. And since it's coming at Mars from outside direction (towards the sun) it could conceivably throw a huge swarm of asteroids into the inner planets including Earth, Venus and Mercury.

This should be really interesting in the months ahead as they further refine the orbit with additional measurements.

JPL is great to include the orbits as calculated so far.

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013A1;cad=1;orb=1;co v=0;log=0#orb

[wowlfie]

It should be clearly visible from Earth in broad daylight. Nearly as bright as the sun for a few moments. The energy released would be over 20 billion megatons.

[Limax7]

The comet don't have 50 km
Hale-Bopp has 60 km, but C/2013 A1 maybe 8-14 km

[TheAstroChannel]

This is something to put on my calendar definitely!! it is disturbing to think about it but at the same time simply awesome! I really hope the mars rover's aren't damaged, or even worse, destroyed in the process.

[mamasinham]

The thing I find astonishing about this comet relates to the 500km wide, 2km deep crater, that'll result from a direct impact. People around me are cooing in wonder, and saying things like: "Ooh, Ahhh, hope it hits, won't it look pretty." I, however, am furrowing my brow, as deep as it'll go, at the thought of how much of Mars' surface, which used to occupy that crater, will be flung into the void, and sent tumbling through the inner solar system. We're surely in for a pummelling, too, if collision occurs. If not right away, then quite probably after from orbiting bits of it.

[tonybarry]

The seriousness of the impact cannot be overstated.

Estimates of velocity (>50km/sec) and size (> 50km diameter) along with the tenuous nature of Mar's atmosphere mean the inner solar system will likely be unfit for safe space travel for a very long time (in human reckoning).

The ejecta will spread far and wide, and there will be big lumps in it. The earth orbit debris caused by one Chinese satellite collision will be absolutely nothing compared to the mess C/2013 A1 will cause if it hits Mars.

I really hope that it does not impact. But if it does, our troubles have just begun.

Regards,
Tony Barry

[Steffen]

I tend to agree. As much as I'm curious to witness such an event I'm afraid we're very much in the splatter zone.

Cheers
Steffen.

[mamasinham]

"Ejecta!" That's the word I was searching for.

[Greg Bryant]

Today saw the publication of pre-discovery observations from last October, extending the arc quite significantly. The "miss" distance continues to move closer to Mars, and an impact (albeit extremely unlikely) still can't be ruled out.

I've been keeping an eye on the updates since January when the close approach was first identified, and it's been interesting to see the path keep getting closer.

The latest orbit has the comet's nominal miss distance at just 0.00036 au.

Greg

[tonybarry]

The Wiki page has an interesting table about the refinement of the orbit and the expected minimum separation distance.

http://en.wikipedia.org/wiki/C/2013_A1

I think this will be a comet to watch.

Regards,
Tony Barry

[renormalised]

I think all too many of you are getting carried away with "doom and gloom" hysteria here. Let's just get a little bit of perspective here.

Yes, if this comet does look like it will impact Mars, it doesn't matter what it is made out of, it will impact. Even if it comes in at a shallow angle, i.e. travels through a lot of atmosphere before it impacts. Mars' atmosphere is too thin to prevent bodies of a significant size from impacting (anything larger than about 1 metre in size, and of the right composition). It will also most likely be a significant impact, just given the kinetic energy derived from its orbital velocity. However, the final explosion equivalent will be predicated on just how large the comet's nucleus actually is. That's yet to be really determined. If it is 50km in size, the amount of energy imparted on impact will be a simple matter of its kinetic energy on impact...which will be large. As to its size compared to Chicxulub, that depends on its composition. Typical comets have a density of around 1.2-2.5 grams per cubic centimetre. That directly effects its mass and therefore the kinetic energy of the impact. The Chicxulub impactor was a stony-iron asteroid, which have densities around 3.2-5 grams per cubic centimetre (depending on iron content).

Now, for the ejecta from the impact...whether any of it heads towards our planet and collides with it will depend on so many extraneous factors that the only thing that can be said about this is that it is possible, but not probable. It depends on where the comet hits on the planet, the impact energy and how much debris is lofted out of the Martian gravity well. As for large pieces being blasted out that could cause significant damage to Earth, that is taking things a little too far. Any pieces which did come towards our planet would be on the order of the Chelyabinsk Meteorite at their largest, however it's the numbers of pieces which would be of concern. As for splitting Mars apart...there's no worries that this will happen. It would take many orders of magnitude a strike on a planet the size of Mars, than this object could deliver, to blast the planet into debris. There's no need for any apocalyptic nonsense to be spread around in this forum or any other.

[tonybarry]

Hi Carl,

I refer you to the following paper which may possibly answer your doubts.

http://www.gps.caltech.edu/~asimow/TJA_LindhurstLabWebsite/ListPublications/Papers_pdf/Seismo_958.pdf

The original speculation was that the inner solar system would be less safe for travel as a result of a >50km/sec impact on Mars by a >20km cometary body, primarily as a result of ejecta from the impact exceeding Martian escape velocity and entering into unpredictable orbits around the sun.

The question might be better posed as, "How much more likely is a micrometeoroid impact on a spacecraft in Martian or Earth orbit as a result of this (as yet uncertain) impact ?"

To that question I have no answer as yet. Gut feelings (always dubious as I am sure you are aware) tell me that it will significantly raise the risk. Hard numbers would be much more confidence building. To that end I continue to investigate.

Note that the paper by O'Keefe cited above is by an author who advocates the non-terrestrial origin of tektites. In this, the balance of opinion has shifted towards a terrestrial origin (i.e local impacts) rather than the lunar impacts suggested by O'Keefe.

Regards,
Tony Barry

[Robh]

Hi Guys,

I'm inclined to think the chances of a hit is very small. Space is big.
Even if you take the projected bypass distance as roughly 100,000km and the radius of Mars as 3,400km the likelihood of a purely random hit would be about (3,400/100,000)^2 or roughly 1 in 865 as the error radius is 100,000km.
Of course, the chances of impact is not purely random as there would be certain confidence levels built into the calculated trajectory and these will build over time.

If the path of the comet is, as suggested in an earlier post, to be more or less normal to Mar's orbit the likelihood of Mars inflecting the comet, in my opinion, is pretty much zilch.

Regards, Rob

[mccann73]

If by some remote chance this comet does impact, as well any possible effects on earth, it would be interesting to see the long term effects on Mars, apart from the obvious destruction at the impact zone, wouldn’t the amount of dust and material thrown into the atmosphere have an impact on global temperature (atmosphere and land), depending on the location would the impact zone melt large amounts of permafrost, increasing the atmospheric pressure, possibly even enough for running water?


Cheers
Andrew

[tonybarry]

Hi Rob,

You are absolutely correct. Leonid Elenin has published a graph of Mote Carlo simulations of the impact probability - and it's probably not a lot better than winning Lotto.

http://spaceobs.org/en/

The most likely outcome is a close pass. And that's all.

As the comet sheds surface material during its time nearer the sun, we can expect that objects in Mars orbit may ***possibly*** experience micro impacts as a result. Phit Plait (of BadAstronomy fame) discusses this.

http://www.slate.com/blogs/bad_astronomy/2013/02/28/mars_impact_the_red_planet_may_get_ hit_by_a_comet_in_october_2014.html

Regards,
Tony Barry

[Kal]

Fascinating.

Imagine the drama we would be facing if this was coming this close to earth instead of mars.

*goes to watch armageddon*

[carl37]

New orbit out from JPL.

Using 183 observations over 154 days, they've revised the nominal approach distance to 0.000736 AU, with a maximum distance of 0.0023 AU.

In lay terms, that's 110,000km and 350,000km respectively. A bit further away than the last estimate.

[TheAstroChannel]

Some good news!

[snas]

Straight up I'll admit to being probably wrong, so let me know if I am, but, I seem to recall the famous Antarctic meteorite which was ejected from Mars after a collision with whatever it was that collided with Mars to cause said ejection. This meteorite supposedly showed evidence of life on Mars, I'm sure you all know the one I'm referring to. It was apparently estimated that it took some million/s of years from being ejected from Mars to landing in Antarctica. Given the same time span for ejecta from the possible up-coming comet/Mars collision, that out not to be a problem for us.

Or could this be a case of KE on impact being far greater than the impact that led to the meteorite landing in Antarctica, and thus a greatly shortened time span from Mars to Earth.

Stuart

[tonybarry]

Hi Stuart,

Think of a game of billiards when the first player breaks the triangle. The balls go everywhere. In the same way, C/2013 A1 impacting Mars would scatter stuff widely.

THe difference between billiards and the comet impact is that space is vast and the ejecta (even though millions of tonnes in weight) is tiny by comparison.

What this would do is increase the risk of impact (by micrometeors) to space vehicles. The obvious question is ... by how much ? but to that I have as yet no answer. Gut feelings say ... considerably increased risk. But guts are notoriously inaccurate calculators.

Regards,
Tony Barry

[moozoo]

I tried find_orb first as well.

If you import the 183 observations from MPC into Exorb (http://chemistry.unina.it/~alvitagl/solex/) and then load that into Solex and run a close encounters scan, you will end up with almost exactly the same result as is displayed on the jpl site. i.e. 0.0007 au.
You can also use Exorb to generate a large number of Monty Carlo data fits and then run them all though Solex to generate a histogram of close approaches.

[mithrandir]

Do you need the full version of SOLEX or will the Lite version work?

There are now 213 observations in MPEC, and after find_orb discarded 4 outliers, SNP now predicts 64822Km at altitude 65° from a Abalos Undae, Mars (81N, 83W) at 18:37 UTC on 2014-10-19. With a bit of hunting I might find where it will be nearer to the zenith at closest approach.

[moozoo]

From memory the Lite version will work fine. The full version is postcard ware and includes alot more stars and asteroids.

Solex is a very accurate numerical intergrator, comparable to the jpl one.
The documentation give a large number of graphs showing the errors between solex and jpl's DE421 and DE406 over 10000+ years.

I've attached a histogram generated from 1256 monty carlo generated fits to the observations. I didn't remove any outliers. I have since worked out how in EXORB to find and remove the 4 you mentioned. It didn't make much of a difference to the best fit. So I doubt the histogram will be very different either.

http://moozoo.dyndns.org/misc/MINDIST.jpg
I also posted this at http://cosmoquest.org/forum/showthread.php?142631-Possible-Comet-Collision-with-Mars/page5

[mithrandir]

I've tried exorb7 with the MPEC data I have today and I must be doing something wrong because the elements it generates are nothing like what I get out of find_orb with the same data, or the values from MPC or JPL. Maybe we could take this offline.

[moozoo]

Video of computing comet close approach using exorb and solex http://moozoo.dyndns.org/C2013A1/C2013A1Solex.mp4

Using the Extras option (!) you can increase the order of the intergration and enable the use of 80bit floats. It doesn't make much of a difference.

To use findorb to compute the orbit and then use solex to do the intergration you need to use findorb's "Make Ephemeris"
http://moozoo.dyndns.org/C2013A1/findorb.jpg
Take a copy of the C2013A1.SLX file and edit in the findorb values.
To convert to the units used by solex
Take the 1st number and replace the first line in the .slx file with it
Take the 2nd,3rd and 4th numbers and multiply by 149597870.691/1000000 and replace the 3rd line in the .slx file with it
Take the 5th,6th and 7th numbers and multiply by 149597870.691/(24*60*60) and replace the 4th line in the .slx file with it

The 149597870.691 is the AU_TO_KM constant in the findorb source
The result
--------------
2456205.093440
0 0 0 0.0000000E+00 C2013A1
1.3102997512433800E+02 1.1404778167143200E+03 -2.9852251770828400E+02
3.1353047253305100E+00 -1.4621796132689200E+01 -5.2773661621146100E-01
0.00000000E+00 0.00000000E+00 0.00000000E+00 1.11000000E-01
--------------------------------

Solex using a filtered (residuals over 1.5 removed) findorb orbit gave a close approach of 145614 km at 18:25

[mithrandir]

With the current 220 (less 4) observations, find_orb predicts 125997 km at 18:39 UTC.

If I set find_orb's std dev filter to 1.5 it eliminates 8 observations and the closest approach increases to 133002 km.

If I follow your steps exactly I get the same values from EXORB/SOLEX. I have all the MPEC K12 and K13 files and while extracting all the K13A010 records should give something identical to the file you get from the DB query it doesn't seem to do so.

[starchild]

I agree with you on that Andrew! I wonder if it would change the global temperature... :rain:

Cheers,
guillaume

[mithrandir]

With every additional set of observations from the MPC (now 247 less 4 outliers) a hit seem less likely.

Today's projected close approach is 135741 km.

[tonybarry]

Universe Today posts an article on C/2013 A1 - effectively ruling out a cometary impact on Mars.

http://www.universetoday.com/101437/new-calculations-effectively-rule-out-comet-impacting-mars-in-2014/#more-101437

Odds are less than 1 to 1e5 against.

Regards,
Tony Barry