Asteroid may hit Mars, 1 in 75 chance. Tunguska sized

silylene old · Dec 20, 2007

Quite Interesting! If this were Earth, this would be a Torino scale 4 or 5. link <blockquote>In reply to:<hr /> -------------------------------------------------------------------------------- Scientists say asteroid may hit Mars By ALICIA CHANG, AP Science Writer LOS ANGELES - Mars could be in for an asteroid hit. A newly discovered hunk of space rock has a 1 in 75 chance of slamming into the Red Planet on Jan. 30, scientists said Thursday. "These odds are extremely unusual. We frequently work with really long odds when we track ... threatening asteroids," said Steve Chesley, an astronomer with the Near Earth Object Program at NASA's Jet Propulsion Laboratory. The asteroid, known as 2007 WD5, was discovered in late November and is similar in size to the Tunguska object that hit remote central Siberia in 1908, unleashing energy equivalent to a 15-megaton nuclear bomb that wiped out 60 million trees. Scientists tracking the asteroid, which is halfway to Mars, initially put the odds of impact at 1 in 350 and increased the chances this week after analyzing the data. Scientists expect the odds to diminish again early next month after getting new observations of the asteroid's orbit, Chesley said. "We know that it's going to fly by Mars and most likely going to miss, but there's a possibility of an impact," he said. If the asteroid does smash into Mars, it'll likely aim near the equator close to where the rover Opportunity has been exploring the Martian plains since 2004. The robot is not in danger because it lies outside the impact zone. Speeding at 8 miles a second, a collision would carve a hole the size of the famed Meteor Crater in Arizona. In 2004, fragments of the comet Shoemaker-Levy 9 smacked into Jupiter, creating a series of overlapping fireba</blockquote> <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

JonClarke · Dec 20, 2007

That would be very exciting indeed! And very instructive. Steve Squyres said at a conference I attended in 2005 that after they investigated the meteorite and the heatshield that they should move away from the area as obviously things fell from the sky there..... Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

phaze · Dec 20, 2007

Sounds like a good beginning to a science-fiction movie to me! Seriously... that would be great. Love to see what we've got after impact.

qso1 · Dec 21, 2007

It would be quite a site if the opportunity rover could image the sky in the direction of the impact, assuming an impact occurs. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

docm · Dec 21, 2007

Too bad Oppy doesn't have one of the tiny MPEG-4 HD camcorders wired to her systems. THAT would be a cool clip.... <div class="Discussion_UserSignature"> </div>

qso1 · Dec 21, 2007

Thats for sure. Maybe a series of still images can be put together but probably not enough for a movie, even a 10 FPS jerk frame movie. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Kalstang · Dec 21, 2007

Gosh darn it!! I just saw that article and was about to post it!! lol Yeah it would be great if they could image it. Wonder if they will try... <div class="Discussion_UserSignature"> I have an answer for everything...you may not like the answer or it may not satisfy your curiosity..but it will still be an answer. "Imagination is more important then Knowledge" ~Albert Einstien~ Guns dont kill people. People kill people.Solar System </div>

deapfreeze · Dec 21, 2007

This will be cool. We should be able to use this info if it happens to further our asteroid earth collision defense. <div class="Discussion_UserSignature"> William ( deapfreeze ) Hooperhttp://deapfreeze-amateur-astronomy.tk/ </div>

deapfreeze · Dec 21, 2007

If this does happen. I think the race to defend ourselves from the large rocks falling from space will begin to explode with ideas. I do hope to see some pictures of it if it happens that is. <div class="Discussion_UserSignature"> William ( deapfreeze ) Hooperhttp://deapfreeze-amateur-astronomy.tk/ </div>

billslugg · Dec 21, 2007

Shame on you. We simply cannot afford to lose another 60 million trees. The Martians have it bad enough as it is. <div class="Discussion_UserSignature"> </div>

brigandier · Dec 21, 2007

It's been a while since Mars saw some decent action

silylene old · Dec 21, 2007

With the thinner martian atmosphere, I bet this would not explode in the air, but actually impact, or at least break up much closer to the surface. Here are the effects from the U Arizona impact model, if this asteroid were to hit the earth. Unfortunately, in their model you cannot adjust the atmospheric density. Your Inputs: Distance from Impact: 50.00 km = 31.05 miles Projectile Diameter: 75.00 m = 246.00 ft = 0.05 miles Projectile Density: 3000 kg/m3 Impact Velocity: 20.00 km/s = 12.42 miles/s Impact Angle: 90 degrees Target Density: 2500 kg/m3 Target Type: Sedimentary Rock Energy: Energy before atmospheric entry: 1.33 x 1017 Joules = 3.17 x 101 MegaTons TNT The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.6 x 103years Atmospheric Entry: The projectile begins to breakup at an altitude of 56600 meters = 186000 ft The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 8.98 km/s = 5.57 miles/s The impact energy is 2.67 x 1016 Joules = 6.38 MegaTons. The broken projectile fragments strike the ground in an ellipse of dimension 0.408 km by 0.408 km Major Global Changes: The Earth is not strongly disturbed by the impact and loses negligible mass. The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis. The impact does not shift the Earth's orbit noticeably. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

MeteorWayne · Dec 21, 2007

On a related note link The Tunguska impactor may have been smaller than we thought. "ALBUQUERQUE, N.M. â€” The stunning amount of forest devastation at Tunguska a century ago in Siberia may have been caused by an asteroid only a fraction as large as previously published estimates, Sandia National Laboratories supercomputer simulations suggest. â€œThe asteroid that caused the extensive damage was much smaller than we had thought,â€ says Sandia principal investigator Mark Boslough of the impact that occurred June 30, 1908. â€œThat such a small object can do this kind of destruction suggests that smaller asteroids are something to consider. Their smaller size indicates such collisions are not as improbable as we had believed.â€ Because smaller asteroids approach Earth statistically more frequently than larger ones, he says, â€œWe should be making more efforts at detecting the smaller ones than we have till now.â€ The new simulation â€” which more closely matches the widely known facts of destruction than earlier models â€” shows that the center of mass of an asteroid exploding above the ground is transported downward at speeds faster than sound. It takes the form of a high-temperature jet of expanding gas called a fireball." <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Smersh · Dec 21, 2007

If this does happen. I think the race to defend ourselves from the large rocks falling from space will begin to explode with ideas. I do hope to see some pictures of it if it happens that is. Absolutely. I think we should be positive about it and, if it does hit, observe the impact and learn as much as we can from it. At least it won't cause any mega-tsunamis ... <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea." Churchill: "Nancy, if you were my wife, I'd drink it."Website / forums </div>

silylene old · Dec 21, 2007

Thanks MW for that link. It had more details. I had seen a less detailed report, and so I adjusted with the impactor size to yield an impact of about 5 MTons above (my example posted above was 6.8 MTons). Have you seen any reports on where on the Martian surface it is considered most likely to hit? Personally, I think a strike on a polar cap would be most interesting. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

MeteorWayne · Dec 21, 2007

From your link <img src="/images/icons/smile.gif" /> ] It says near the equator in the vicinity of (but not too close to ) Oppy. I haven't found any more detailed targeting info yet, but I'm looking when I can. Kinda busy today. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

robnissen · Dec 21, 2007

Yeah it would be great if they could image it. Wonder if they will try... This blog says they will try: http://www.livescience.com/blogs/author/leonarddavid They are not terribly optimistic that they will see much: Squyres added that the rover team, of course, would try to image the sky at the predicted time of impact to see if anything can be seen, â€œbut thatâ€™s got to be considered a very improbable long shot.â€/safety_wrapper>

Smersh · Dec 21, 2007

Thanks MW for that link. It had more details. I had seen a less detailed report, and so I adjusted with the impactor size to yield an impact of about 5 MTons above (my example posted above was 6.8 MTons). I'm guessing that such an impact could result in the mother of all Martian dust storms, lasting for several years perhaps? <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea." Churchill: "Nancy, if you were my wife, I'd drink it."Website / forums </div>

3488 · Dec 21, 2007

I have only just seen this story. Wow, this is most exciting & interesting. Certainly a real scoop. 1 in 75, though still quite low odds, is far higher than for most incidents like this. I will try & find when 2007 WD5 & Mars are at their closest & see where that point is. I do not suppose if the impact site is east or west of Oppy? If this does happen, then hopefully either Mars Express or MRO or maybe both will actually observe the impact & certainly observe the resulting crater. Looking at the orbit diagram, it looks like a day time potential impact as 2007 WD5 will approach Mars from the sunward side. Lets hope we get more news on the orbital elements. Of course the type of the resultant impact will also depend on the nature of 2007 WD5. Is is rubble pile or a solid coherent body? What Type is it? S type, C type, etc? what ever, MER B Opportunity according to the article looks well placed to observe after effects, such as elevated dust levels etc. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Dec 21, 2007

Interesting, 2007 WD5 came within 18.6 Lunar Distance of earth on Nov 1. I wonder what a near miss (which is 74/75 liikely) with Mars will do to future earth approaches. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Dec 21, 2007

<img src="/images/icons/smile.gif" /> Interesting, the orbital period is ~ 4 years, so depending of deflection by mars, could come close to earth again in about 4 years. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Dec 21, 2007

It's not in the Dinosaur Killer class, much too small. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Dec 21, 2007

While I was investigating this, I ran across a very close approach by an asteroid recently. On December 13th a small (10-23 Meter) asteroid came with 0.3 Lunar distance of the earth. It's 2007 XB23 That's mighty close!!! the next closest approach during the next 6 months is 2007 TU24, which will come withing 1.4 lunar distances on January 29th. And it's no Tunguska sized rock, being 250-560 meters in diameter. Whew! MW Edit: Added 2007 TU24 info <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Dec 21, 2007

Hi MeteorWayne, I found this artist's rendering of the path of 2007 WD5 past Mars. Looks like the impact site if it happens is to the west of MER B Opportunity. Thank you for the tipoff about 2007 XB23. Although such a tiny asteroid, that is far TOO close for comfort. <img src="/images/icons/crazy.gif" /> That is large enough to survive atmospheric entry isn't it? Edited, couldn't resist posting 2007 TU24 data here Thanks MeteorWayne. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Dec 21, 2007

Regarding Tunguska, I found a new size estimate that was not in the article. this is from NEO NEws: The main story in this edition of NEO News concerns a proposed downsizing of the energy of the 1908 Tunguska airburst, with associated increase in the expected frequency of such impacts. Mark Boslough of Sandia has generated supercomputer simulations of the Tunguska atmospheric explosion. In part his models require less energy in the explosion because he includes the substantial downward momentum of the rocky impactor, rather then modeling it as a stationary explosion. If this revision (down to an estimated energy of 3-5 megatons, and a corresponding diameter of about 50 meters) is correct, the expected frequency of such impacts changes, from once in a couple of millennia to once in a few hundred years. If smaller impactors can do the damage previously associated with larger ones, of course, the total hazard from such impacts is increased. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Asteroid may hit Mars, 1 in 75 chance. Tunguska sized

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