This is going to be a big year for cometary science, no doubt about it. Already spoiled by having countless Gigglybytes of Comet ISON and Lovejoy data to drool over, cometary scientists are already giddy with anticipation about two other big cometary events which will take place later this year.

I’ve already described on a separate page how, in August, the ROSETTA probe will encounter a comet, sending back pictures of its nucleus before actually landing a smaller probe ON it. But later in the year, in the middle of October in fact, another comet will, I think, dominate the headlines, and will, inevitably, have the same conspiracy nutters who wet their pants over Comet ISON Tweeting and YouTubing the kind of absolute Doomsday apocalyptic b*****ks about it which will make their ISON rubbish seem tame.

In October a comet called SIDING SPRING will have a close encounter with the planet Mars. A VERY close encounter in astronomical terms. Last year, when the comet was found but before its orbit was known accurately it seemed possible that it might actually be going to HIT Mars, a cosmic collision which would have been a once in ten lifetimes event, and astronomers were torn between dismissing the idea as far-fetched and ridiculous and thinking “YES! I WANT TO SEE THAT!” because if a comet (or asteroid) did strike Mars it would be incredibly exciting scientifically to be able to study a brand new hole blasted out of the planet, and the effects on the planet’s surface, weather and more after it. But as more and more observations of the comet were made it became clear that there was actually very little chance of a collision, and now the chances of an impact are put at just 1 in 120,000. Big relief for the teams behind the Mars rovers, who really didn’t fancy having their precious machines bombarded by chunks of flaming rock falling from the sky, or smothered beneath a layer of Sun-obscuring dust, but, maybe, disappointing for anyone who had imagined what an amazing fireworks display such a cometary impact might produce.

So, Comet SIDING SPRING is going to come very close to Mars, but won’t hit it. How close will it come? Well, the latest estimates suggest it will miss Mars by over 100,000 km. That’s a long way. A LONG way. To give you an idea just how far away that is, Mars’ two moons, Phobos and Deimos, orbit Mars at distances of 9.377km and 23,500km respectively, so the comet isn’t even going to pass within the orbit of Mars’ farthest moon. To give you a sense of perspective, the distance of the closest (so far) calculated approach of the comet to Mars – 129,000km – is equivalent to around NINETEEN TIMES THE WIDTH OF MARS ITSELF! And the furthest calculated closest approach distance, 157,000km, is equivalent to over TWENTY THREE TIMES the width of Mars. So, a collision is looking very, very unlikely based on the most recent observations and figures. There’s nothing to worry about.

…which means, of course, that the brigades of Doomsday-loving, Apocalypse-worshipping. science ignorant fruit loops and whackos who spouted such BS about Comet ISON are already gearing up for this event, and preparing to completely ignore the science, and the facts, and the maths, and swamp the internet with their warnings, predictions and despair. Listen carefully and you will be able to hear them limbering up right now, cracking their fingers above their computer keyboards like pianists before a concert, preparing to make their ridiculous YouTube videos and spread their scaremongering bull**** on Twitter and Facebook. There are already pages on the “alternative forums” dedicated to Siding Spring, already posters saying that NASA are lying, and hiding the truth. It won’t be long, surely, until some tin foil hat-wearing looney insists that the comet is actually Nibiru, or an extraterrestrial spaceship, or a fleet of UFOs, or an alien biosphere, repeating the same juvenile crap they spouted about ISON. Oh well, if they want to waste their lives believing and spreading such childish, ignorant fantasies that’s up to them. The rest of us can look forward to a very rare, very exciting astronomical event later in the year which will have the media in just as much of a frenzy as the Nibiru Nutters!

But what might we actually see?

Well, obviously the best views are going to come from Mars itself, or rather from the various orbiters and rovers there. There’s a chance that the comet will appear bright enough from Mars to be visible to the cameras of these spacecraft, so we might get some pictures from the rovers Opportunity and Curiosity showing the comet in Mars’ sky, such as this gorgeous painting by space artist Kim Poor, which is decidedly “vintage” now but still beautiful…


NOTE: the actual pictures taken from Mars – if any ARE taken – will almost certainly be NOWHERE NEAR AS IMPRESSIVE AS THAT! I imagine the comet would look a lot smaller, and much, much fainter and fuzzier. Same goes for the Mars rover pic at the top of this page. That’s just for illustrative reasons, it’s NOT me predicting or suggesting the comet will look ANYTHING LIKE THAT for real, ok?

And the various orbiters studying Mars will turn their cameras towards the comet as it flies past, hoping to capture something. Actually, there is some concern for those priceless assets. Although the comet’s nucleus will miss Mars by a fair distance, that nucleus will be surrounded by an enormous cloud of gas and dust, the “coma”, and Mars may well be enveloped by that cloud as the comet passes. What might happen? Well, Mars might experience a dramatic meteor shower – or even a “storm” – as the cometary dust streaks through and burns up in its atmosphere, as thin as it is, and the Mars rovers will surely try and get pictures if anything like that happens, But the orbiting spacecraft might be at risk from a “cometary sandblasting” if Siding Spring’s coma and tail reach them. Hopefully not.

As for viewing events from here on Earth, that’s a different matter.Visually the comet won’t be a naked eye object, looking at the latest predictions anyway, so anything we see of this epic Close Encounter will have to be through a telescope. And although we won’t see any celestial fireworks, it should be possible – and very cool! – to see the tiny, orange-red disc of Mars and a comet in the same field of view on October 19th, “Encounter Day”.

BUT… that will be something best seen by observers in the southern hemisphere. From south of the equator Mars and the comet will be visible high in a dark sky, and astrophotographers from Australia to Argentina will be taking pictures of and watching them on that night!


Up here in the north, Mars and the comet will be low in a still fairly bright sky, making them hard to observe and photograph. We’ll still try tho!


So, that’s something to look forward to, isn’t it? Obviously I’ll be covering this fascinating event on this blog, which will no doubt lead to me being sent foul-mouthed abuse and threats from the same nutters who I called out about Comet ISON, and I’ll almost certainly find myself banned from the conspiracy theory/alternative news chemtrail-loving internet forums whose deluded members use my images and posts to support their crackpot ideas, but I can live with that. 🙂

Watch this space for more SIDING SPRING news.

4 Responses to “Comet SIDING SPRING”

  1. Is it very likely that there would be much of a cometary tail to be seen by mars orbiters and rovers? I suspect mars is too far away for any real cometary tail to appear…and our devices around that planet would probably just pick up a hazy coma round a bright nucleus, no?

    • The comet is showing a small tail already, which is very promising.

      • Already has a tail? Wow, promising indeed! How close will this one be coming to Earth? Close enough for a naked eye view, or will it only be visible to ‘scopes?

  2. Really appreciated you running blog for ISON. While I didn’t get much of a chance to see it here in the States… light pollution blows in DC…truly enjoyed the time trying.

    About the above comment on how Siding would appear as seen from Mars is to put it into a perspective relative to Earthly terms more folks can follow perhaps. Even at 129k Km. if Siding were passing that close to Earth it would be only 1/3 the distance to our Moon. Even a moderate tail I would imagine at that close of a passage would be impressive wouldn’t it?

    Keep up the great work.

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