Is a comet on a collision course with Mars?

Feb 27, 2013 by Nancy Atkinson, Universe Today
Simulation of the close approach of C/2013 A1 to Mars in Celestia using the latest info from the Minor Planet Center. Credit: Ian Musgrave/Astroblog

There is an outside chance that a newly discovered comet might be on a collision course with Mars. Astronomers are still determining the trajectory of the comet, named C/2013 A1 (Siding Spring), but at the very least, it is going to come fairly close to the Red Planet in October of 2014. "Even if it doesn't impact it will look pretty good from Earth, and spectacular from Mars," wrote Australian amateur astronomer Ian Musgrave, "probably a magnitude -4 comet as seen from Mars's surface."

The was discovered in the beginning of 2013 by comet-hunter Robert McNaught at the Siding Spring Observatory in New South Wales, Australia. According to a discussion on the IceInSpace amateur astronomy forum when the discovery was initially made, astronomers at the 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 right through orbit on Oct. 19, 2014.

However, now after 74 days of observations, comet specialist Leonid Elenin notes that current calculations put the closest approach of the comet at a distance of 109,200 km, or 0.00073 AU from Mars in October 2014. That close pass has many wondering if any of the Mars orbiters might be able to acquire high-resolution images of the comet as is passes by.

Fragments of Shoemaker-Levy 9 on approach to Jupiter. Credit: NASA/HST

But as Ian O'Neill from Discovery Space points out, since 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)," Ian wrote, "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)."

Elenin said that since C/2013 A1 is a hyperbolic comet and moves in a retrograde orbit, its velocity with respect to the planet will be very high, approximately 56 km/s. "With the current estimate of the absolute magnitude of the nucleus M2 = 10.3, which might indicate the diameter up to 50 km, the energy of impact might reach the equivalent of staggering 2×10¹º megatons!"

An impact of this magnitude would leave a crater 500 km across and 2 km deep, Elenin said.

While the massive Comet Shoemaker–Levy 9 (15 km in diameter) that crashed into Jupiter in 1994 was spectacular as seen from Earth orbit by the Hubble Space Telescope, an event like C/2013 A1 slamming into Mars would be off the charts.

Astronomers are certainly keeping an eye on this comet, and they will refine their measurements as more data comes in. You can see the orbital parameters available so far at JPL's Solar System Dynamics website.

We'll keep you posted.

Explore further: Storms threaten second launch try to space station

add to favorites email to friend print save as pdf

Related Stories

Comet ISON shaping up to be a spectacular display

Jan 15, 2013

(Phys.org)—Excitement is mounting for astronomers and star gazers the world over as word spreads that Comet ISON may go down in the history books as one of the flashiest ever. First discovered in September ...

Comet Elenin: Preview of a coming attraction

May 05, 2011

(PhysOrg.com) -- You may have heard the news: Comet Elenin is coming to the inner-solar system this fall. Comet Elenin (also known by its astronomical name C/2010 X1), was first detected on Dec. 10, 2010 by ...

Comet Pan-STARRS: How bright will it get?

Sep 06, 2012

Early next year, a comet will come fairly close to Earth and the Sun—traveling within the orbit of Mercury—and it has the potential to be visible to the naked eye. Amateur and professional astronomers ...

Boosting the accuracy of Rosetta's Earth approach

Oct 19, 2007

Yesterday, 18 October at 18:06 CEST, the thrusters of ESA’s comet chaser, Rosetta, were fired in a planned, 42-second trajectory correction manoeuvre designed to 'fine tune' the spacecraft's approach to ...

Recommended for you

SpaceX launches supplies to space station (Update)

6 hours ago

The SpaceX company returned to orbit Friday, launching fresh supplies to the International Space Station after more than a month's delay and setting the stage for urgent spacewalking repairs.

Sun emits a mid-level solar flare

6 hours ago

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

Impact glass stores biodata for millions of years

9 hours ago

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

The importance of plumes

9 hours ago

The Hubble Space Telescope is famous for finding black holes. It can pick out thousands of galaxies in a patch of sky the size of a thumbprint. The most powerful space telescope ever built, the Hubble provided ...

Ceres and Vesta Converge in Virgo

12 hours ago

Don't let them pass you by. Right now and continuing through July, the biggest and brightest asteroids will be running on nearly parallel tracks in the constellation Virgo and so close together they'll easily ...

User comments : 26

Adjust slider to filter visible comments by rank

Display comments: newest first

Jeddy_Mctedder
2 / 5 (8) Feb 27, 2013
lets send a group of micro sattelites with the first experimental mass drivers on them to see if we can ensure this comet hits mars as fast as possible....bringing water and enerfy to mars for 1) scientific observation 2) terraforming potential experiment 3) drumming up interest in space science and globalawareness of nasa and space research. 4) because its fun 5) to learn how to deflect asteroids and comets from hitting earth by gaining practical engineering knowledge.
Ophelia
1 / 5 (1) Feb 27, 2013
An impact of this magnitude would leave a crater 500 km across and 2 km deep
That's a diameter/depth ratio of 300. According to wikipedia, Meteor Crater in AZ, USA, is 1.2 km in diameter and 170 m deep, a diameter to depth ratio of about 7. I know that ratio won't scale linearly, but that's a huge difference. Seems a bit off.

Anyone able to verify the article numbers?
Ophelia
not rated yet Feb 27, 2013
Sorry about the 300; that should be 250, obviously.
pdalek
5 / 5 (1) Feb 27, 2013
Putting the rough numbers into the Impact: Earth! crater estimator:

Transient Crater Diameter: 262 km ( = 163 miles )
Transient Crater Depth: 92.7 km ( = 57.5 miles )

Final Crater Diameter: 544 km ( = 338 miles )
Final Crater Depth: 1.97 km ( = 1.22 miles )

An impact this big produces a complex crater. Meteor Crater is a simple crater from a small impact.
Ophelia
not rated yet Feb 27, 2013
Thanks, pdalek. That still seems awfully shallow for such a deep initial excavation. I understand there would be a large amount of backfilling, still...
Frostiken
1.8 / 5 (4) Feb 27, 2013
I would imagine it would be shallower on Earth because Earth is, for all intents and purposes, liquid. Mars is considerably more solid... though I imagine at 2x10^10 it would liquify a massive amount of ejecta which would flow back into the hole.

I do greatly hope that this comet hits Mars, this would be a once in a... millenia opportunity. Maybe even more. I'm not sure about deliberately steering it into it, but still, fingers crossed.

I guess the biggest casualties here would be the dust thrown up would probably choke out Spirit, though I guess Curiosity could keep on truckin'.
supersubie
not rated yet Feb 27, 2013
Was going to say If something size does hit mars will the rovers survive? Hope it hits it would be absolutely amazing and such a great opportunity for science.
VendicarE
not rated yet Feb 27, 2013
The rovers would survive, but the orbiter's probably wouldn't.
OttJ
2 / 5 (2) Feb 27, 2013
50 KM? No way the rovers would survive that. They would fry.
TheGhostofOtto1923
2 / 5 (8) Feb 27, 2013
We will need to hit it with a number of comets and asteroids along the equator to spin it up to the equivalent of an earth day, so as to make terraforming with earth flora and fauna more feasible.

No this is not my idea...
Blue Mars, the last book in the Mars Trilogy of Kim Stanley Robinson.
OttJ
1 / 5 (1) Feb 27, 2013
I wouldn't push that dirty snowball anywhere. Hubris is what kills man. What if we make a mistake and send that behemoth toward us?
obama_socks
1.4 / 5 (10) Feb 27, 2013
We will need to hit it with a number of comets and asteroids along the equator to spin it up to the equivalent of an earth day, so as to make terraforming with earth flora and fauna more feasible.

No this is not my idea...
Blue Mars, the last book in the Mars Trilogy of Kim Stanley Robinson.
-Blotto/Theghostofotto1923

But it was your idea to drop your bullshit in this thread as you do with all other threads, only because you have a need to dilute the topics with your astounding bullshitting garbage as you did in:

http://phys.org/n...ple.html

Go take yer meds and get back to your basket weaving, you fraud.
cantdrive85
2 / 5 (9) Feb 27, 2013
The rovers would survive, but the orbiter's probably wouldn't.

Being that the Russian meteor cause an EMP type event and knocked out the local cellular network, I would have to imagine with the energy the comet is packing the EMP event would be much larger and probably knock out all the craft on/near Mars.
nuge
5 / 5 (9) Feb 27, 2013
This object is 50km wide and is travelling at 56 km/s. I think those who are suggesting we could nudge it even fractionally off course in just a year with our current technology are failing to comprehend the raw numerical reality of the situation.
Jeddy_Mctedder
1.7 / 5 (6) Feb 27, 2013
This object is 50km wide and is travelling at 56 km/s. I think those who are suggesting we could nudge it even fractionally off course in just a year with our current technology are failing to comprehend the raw numerical reality of the situation.

this is PRECISELY MY POINT. please see this article. http://transhuman...enterpri

nonsense 'articles' about space defelection of asteroids in utter nonsense when applied to an asteroid above a threshold inertia (speed/mass balance) beyond a certian size, we cant understand how to utilize our supposed technological capabilities to move the asteroid at all, let alone 'deflect it'. for all the nonsense talk about directed energy, we well know our physics leads us to understand that the most easy way to move the asteroid is with mass most easily concentrated on the asteroid itself.
Neinsense99
1 / 5 (5) Mar 01, 2013
Not only would it be difficult to change the orbit of the comet in the short time that is available, we don't yet have enough information on its current trajectory. You can't redirect something to hit a target if you don't quite know where it is going right now.

KSR does not suggest using impactors to increase the spin rate of Mars, as it is already close to that of Earth and already supporting life in his books. That speculation was about Venus, which is a planet that has an unacceptable day length, among other problems.
Neinsense99
1 / 5 (5) Mar 01, 2013
Heads up, Commander X2 (Marvin). Something like that could do much more than block your view of Venus.
astroartuk
not rated yet Mar 03, 2013
Very strange illustration. IF the comet had grown a tail by the time it reached Mars, and we're looking at Mars ('sideways', with its S pole on the left) with the Sun behind us, the head of the comet would be pointing at us and its tail towards Mars. . .
Deck
not rated yet Mar 03, 2013
What would such an impact do to Mars' orbit and rotational period? How would that in turn affect the interactions between planets in the inner solar system?

Lurker2358
2.6 / 5 (5) Mar 03, 2013
What would such an impact do to Mars' orbit and rotational period? How would that in turn affect the interactions between planets in the inner solar system?


While the energy level calculated is about 20 times greater than the Chicxulub event, it is still insignificant with regards to planets' orbits, at least on human time scales.

A one-time acceleration of a planet by something like a nano-meter per second isn't going to make much difference throughout the course of human existence.

If this were to hit Earth, it might stand a good chance of erasing all macroscopic life.
pdalek
not rated yet Mar 03, 2013
If you wish to see how an impact alters planetary orbits and rotation rates then try the Impact: Earth! simulator or most of the other crater estimators. They provide this information for any user specified impact.
LordKinyambiss
not rated yet Mar 04, 2013
And they discover its heading to the equatorial region, specifically, one Gale Crater. Now that would be the funniest piece of tragedy in the History of Space and all other forms of exploration. Zeus forbid.
Anorion
1 / 5 (1) Mar 04, 2013
An impact of this magnitude would leave a crater 500 km across and 2 km deep
That's a diameter/depth ratio of 300. According to wikipedia, Meteor Crater in AZ, USA, is 1.2 km in diameter and 170 m deep, a diameter to depth ratio of about 7. I know that ratio won't scale linearly, but that's a huge difference. Seems a bit off.

Anyone able to verify the article numbers?


Mars's atmospheric mass of 25 teratonnes compares to Earth's 5148 teratonnes. The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi)

means the stellar object would burn much less and be much less slowed, than if it were to enter earth atmosphere, since mars atmosphere is less than 1% that of earth.
Ensign_nemo
not rated yet Mar 04, 2013
The path of comets can not be predicted with precise exactness because they emit gases asymmetrically, which acts like a low-power rocket and adds an intrinsic random element to their trajectory.

They can also split into multiple pieces.

I wonder if the close approach to Mars will have the same effect as the close approach to Jupiter had on Shoemaker-Levy 9 on its next-to-last encounter with Jupiter. It split into multiple pieces, which then impacted the planet on the next loop.
antialias_physorg
1 / 5 (3) Mar 04, 2013
means the stellar object would burn much less and be much less slowed, than if it were to enter earth atmosphere, since mars atmosphere is less than 1% that of earth.

I'm not sure "slowing due to atmosphere" is much of an issue beyond a certain size. The slowing force acts on a surface, while the momentum (and hence the velocity) goes with the volume.
An Earth-type atmosphere would reduce the impact energy of such a motherhuge comet by only a negligible amount.
Reg Mundy
3 / 5 (6) Mar 06, 2013
@antialias_physorg
The slowing force acts on a surface, while the momentum (and hence the velocity) goes with the volume.

No it doesn't go with the volume, it goes with the mass. Dumkopf!

More news stories

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...