Planet Four Talk

We won't want to miss THIS!

  • AUricle by AUricle

    The question of giant outflows of liquid H2O on Mars may be answered in the near future, and the current orbiters might provide us with front row seats! The link is to the Universe Today article. The story is copied from the U.T site.

    This could render what we're doing as somewhat irrelevant.

    http://www.universetoday.com/100298/is-a-comet-on-a-collision-course-with-mars/#

    Here is the story.

    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 comet 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 Catalina Sky Survey 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 Mars 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. *** Updated story has the distance MUCH CLOSER***--> {The NEO Program Office’s current estimate based on observations through March 1, 2013, has it passing about 31,000 miles (50,000 kilometers) from the Red Planet’s surface.} (see link way below the article on the U.T website)

    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.

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  • Kitharode by Kitharode moderator in response to AUricle's comment.

    Good post Auricle. Before that though, there's a good chance of a naked eye comet (Panstarrs) in the northern hemisphere beginning tonight, 7th March, for the next couple of weeks or so. Sky charts and information here: http://earthsky.org/space/comet-panstarrs-possibly-visible-to-eye-in-march-2013

    The comet later this year (November) promises to be even better, possibly visible naked-eye in daylight! But as the article tells us, comets can be very fickle objects.

    I've been lucky with comets - Saw Halley's comet last time round (disappointing) then Hyakatake (very good) and then Hale-Bopp (absolutely awesome). Also saw two impacts from Shoemaker-Levy on Jupiter, live through a 12-inch telescope with CCD attachment (literally out of this world).

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  • AUricle by AUricle

    Right Kith. Best nights for PanSTARRS are 12th -13th up north...at dusk right after sunset. Good luck!
    Agree on Halley's, missed Hale-Bopp, and had my best ever comet exprience with Hyakutake. Watched a closed circuit feed of Shoe-Levy at Jupiter. Live had to be pretty neat!

    I'm anxious for the November event too, but I'm trying to keep a lid on it, because SOoooo many of these things are hyped beyond reason and then are nowhere expectations. I've got over 50yrs of those disappointments. Funny, I've rarely been surprised to the "upside", ya know?

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  • Kitharode by Kitharode moderator

    AUricle. I know exactly what you mean. With only 30yrs experience in the astronomical community I'm a newbie compared to you, but yes, the first sniff of a 'probably maybe perhaps it might just be a good one' gets the astrohype machine quickly into top gear. Can't blame them of course, but I agree the 'upside' events are rarely surprising. Shoemaker-Levy is the obvious exception and yes, seeing it live was incredible indeed.

    You missed Hale-Bopp? The biggest, longest, brightest, awesomest comet in the whole of our lifetimes and you missed it? You must have been in Australia, or totally drunk, or dead (or all of those) 😉

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  • mschwamb by mschwamb scientist, translator

    Universe Today reports a 1/600 chance currently of the comet hitting Mars, so my guess is with future observations that will get revised with an ever lower chance of hitting Mars. So my bet is that it will very a close encounter but no impact. Will be interesting to see if the rovers and the orbiting spacecraft will be able to observe it. If it did hit that would be definitely be something HiRISE I'm sure would image.

    Cheers,
    ~Meg

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  • AUricle by AUricle in response to mschwamb's comment.

    Meg,

    By 'astro'- standards, 1-in-600 is damn near a certainty!....and since the last refinement took it form 108,000 km to 50,000 km, those odds may be getting larger, not smaller.

    Wouldn't it be an incredible event?.....even a near miss captured by the orbiters, or rovers. As the article said, "off the charts". I wonder if ANY data or pix could be obtained by an impact. The planetary destruction, the disruption to the atmosphere, and to near space would probably be HUGE, not ot mention all sorts of disruptive radiation...radio, thermal, etc etc.....might render orbiters AND rovers DOA or at least non-functional. The view from HERE or say Hubble might be the best we can get....which would still be spectacular 😉

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  • Kitharode by Kitharode moderator

    Fingers crossed for the orbiters getting some photo's. I'll have a tenner on 'missed it - what a flop' 😉

    Slightly off-topic but I couldn't resist sharing this short comet Enke video. I'm surprised I've never met it before now. The 'ripping' of the tail is spectacular and the coronal mass ejections are clearly visible. http://en.wikipedia.org/wiki/File:Encke_tail_rip_off.ogg

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  • AUricle by AUricle

    You must have been in Australia, or totally drunk, or dead

    Hmmm...2 of 3 are actually pleasant ideas, Kith 😉 .........but I think it was just a really bad run of Chicago weather, coupled with a lot of family responsibilities back in those days, that salted my tail.....and before ya know it, the BIG show was over!

    Guess I'll just have to wait for the next pass...................................................in 4534. Suppose it might be a good idea to 'up' my vitamin regemine, eh?.......or maybe a few thousand years in a glass bottle buried in that south polar grust?

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  • AUricle by AUricle in response to Kitharode's comment.

    In other, somewhat less dramatic news, isn't today the start of the Crufts Dog Show in Birmingham, Kith?

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  • Kitharode by Kitharode moderator

    Don't talk to me about bad weather. I'm in Todmorden, West Yorkshire, UK. Nice when it's nice, but......

    Don't know about Crufts dog show being on today, but I've heard it's World Book Day today. Where do these 'days' come from? How would I get a National Kitharode Day on the calendar? Forget it ... back to fans and blobs.

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  • mschwamb by mschwamb scientist, translator in response to AUricle's comment.

    A less than 0.2 percent chance of impact isn't quite a certainty, but more observations are needed to refine the orbit. I think it's going to be close like 2012 DA14 was for the Earth, but not actually impact. The awesome thing is we can test the hypothesis whether it's going to hit with more observations to refine the orbit. Either way it's a comet to watch closely.

    Cheers,
    ~Meg

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  • Kitharode by Kitharode moderator

    AUricle. The link below is primarily for any non astronomers who visit here, who might like to know more about comets in a single easy to read page. But you might also find it interesting for the mass loss figures included there.

    Having read it myself, I get a distinct feeling that comet coma formation is a bit like an upside-down spider formation. Although wildly different, I can't shrug off the feeling that there are certain things in common. One thing seems clear; there's grust in them thar comets!

    http://www.open.edu/openlearn/science-maths-technology/science/physics-and-astronomy/astronomy/snowballs-space-introduction-comets-their-sizes-and-decay

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  • wassock by wassock moderator

    Speaking of which does anyone know if anyone got a pic of the lump of rock that just missed us t'other week? Like from space?

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  • mschwamb by mschwamb scientist, translator in response to wassock's comment.

    There were images from the Kitt Peak 2.1m and LCOGT's Faulkes South.

    Cheers,

    ~Meg

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  • wassock by wassock moderator

    Thanks Meg, the question was a back handed way of saying dont get too excited about what sort of images the orbiters might get of something passing Mars. If all the cameras on satellites around Earth couldn't photograph something between them and the Earth, what hope for Mars?

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  • Portyankina by Portyankina scientist

    HiRISE team is discussing about imaging the comet and with some luck we may do better than some designated missions! (Rosetta does not count, it's not there yet!)

    Anya

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