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View Full Version : How come that 160-foot-wide asteroid did not hit mars last year ?



TRUTHisnotfacts
2009-Jun-02, 03:21 AM
asteroid 2007 WD5


How ? what made it change its direction at the last hour ?

Jens
2009-Jun-02, 03:35 AM
asteroid 2007 WD5
How ? what made it change its direction at the last hour ?

It didn't. It wasn't going to hit Mars in the first place, so it didn't need to change direction. Why don't you read about it on Wikipedia (http://en.wikipedia.org/wiki/2007_WD5).

Tucson_Tim
2009-Jun-02, 03:39 AM
what made it change its direction at the last hour ?

Why do you believe that it changed direction? Where did you read/hear that?

01101001
2009-Jun-02, 03:42 AM
what made it change its direction at the last hour ?

You assume much.

TRUTHisnotfacts
2009-Jun-02, 04:02 AM
I thought that the Asteroid Had 1 in 75 Odds to Hit Mars ?

1 in 75 chance is not easy to get these days ?

You would need to go way back to even have that good of a chance to for a planet to have that great of a chance to be hit.

The reason that I said ..changed direction at last hour ....was becouse it seems a little Interesting that the 1 in 75 chance did not happen .

Maybe the direction could have changed by the moon of mars

Tucson_Tim
2009-Jun-02, 04:08 AM
Maybe the direction could have changed by the moon of mars

The Barsoomians used the Eighth Ray to deflect it.

nauthiz
2009-Jun-02, 04:18 AM
it seems a little Interesting that the 1 in 75 chance did not happen .

74 out of 75 times, the 1 in 75 chance will not happen.

01101001
2009-Jun-02, 04:26 AM
The reason that I said ..changed direction at last hour ....was becouse it seems a little Interesting that the 1 in 75 chance did not happen .

Even less interesting is that the final estimate of 1 in 10,000 chance probably didn't happen.

Or it did happen. I don't think the experts know the final outcome. Why do you assume the asteroid did not hit Mars?

Tucson_Tim
2009-Jun-02, 04:36 AM
Or it did happen. I don't think the experts know the final outcome. Why do you assume the asteroid did not hit Mars?

Now that's interesting. I didn't realize that 2007 WD5 is now considered "lost". If it had hit Mars, would any of the equipment we have in orbit or on the surface be able to detect the impact?

TRUTHisnotfacts
2009-Jun-02, 04:39 AM
I think that any size over a football field then the object has a good chance to wipe out any life forms or anything that is near where it lands unless its under that Mountian that is 70 000 foot high .

but see we have so many human made objects on mars there would have been a Picture of it by now ? Not only that but I am sure some place someone had there scope on it ...

NickW
2009-Jun-02, 04:42 AM
ummm....what? This may be the most confused you have gotten me, Tinf.

TRUTHisnotfacts
2009-Jun-02, 04:49 AM
I was just asking how come that the object did not hit mars last year and could have it changed its direction ?

There is no pictures or nothing to prove an impact on mars .

And that is sort of strange that its lost now ..where did it go to ?

Gandalf223
2009-Jun-02, 04:55 AM
How ? what made it change its direction at the last hour ?

It missed Mars because it was never going to hit Mars. It did pass very close to the planet.

It is listed as "lost" because it passed so close to Mars (est. 6.5 Mars diameters) that it was likely deflected into a new orbit by Mars' gravity. That doesn't mean it's really "lost" but nobody knows exactly what trajectory it's on. As more observations are made, a new orbit can be calculated.

Either that, or Nibiru's gravity suddenly increased 10,000-fold only in the direction of Mars, and the asteroid is now on its way to smash Nibiru into a gazillion little asterettes.

TRUTHisnotfacts
2009-Jun-02, 05:06 AM
will 2007 WD5 come back to mars ?

How many years do they take to return ?

01101001
2009-Jun-02, 05:30 AM
It missed Mars because it was never going to hit Mars. It did pass very close to the planet.

How do you know it missed?

We left it (topic Asteroid may hit Mars in January (http://www.bautforum.com/1166868-post129.html)):

Planetary Society Weblog: WD5 most likely missed Mars, but we may never know (http://www.planetary.org/blog/article/00001316/)


Now, a 6.5-Mars-radius flyby is quite close enough to alter the course of WD5 significantly. Where's it going to go next? The answer is, no one knows. The uncertainty surrounding WD5's exact position with respect to Mars during the encounter hugely balloons when you try to figure out its future path. It essentially got a gravity assist from Mars, but without knowing exactly at what distance and, equally importantly, at what latitude it flew past the planet, we have no idea where Mars flung it.

[...]WD5 is now considered lost. That may sound sad or possibly even dangerous, but [JPL's Steven Chesley] emphasized to me that becoming lost is quite the norm for objects as small as WD5, which is estimated to be roughly 50 meters in diameter.

Is there an update that shows it definitely missed?

Edit: Never mind. I found one.

Astronomers Rule Out Possibility of Asteroid Impact on Mars (http://www.jpl.nasa.gov/news/news.cfm?release=2007-152)


January 11, 2008

Updated Jan 9, 2008 – As expected, scientists at JPL's Near-Earth Object Office have further refined the trajectory estimate for asteroid 2007 WD5 and ruled out any possibility of a Mars impact on Jan. 30. The latest trajectory plot of the asteroid was made possible by adding to previously obtained data some new data from a round of observations acquired by three observatories on the evenings of Jan. 5 through 8. Based on this latest analysis, the odds for the asteroid impacting Mars on Jan. 30 are 0.0 percent. The latest observations come from the German-Spanish Astronomical Center, Calar Alto, Spain; the Multi-Mirror Telescope, Mt. Hopkins, Ariz.; and the University of Hawaii telescope, Mauna Kea, Hawaii.

Edit: but after that, some were still writing, later (Planetary Society so appears, but is currently unreachable), that the outcome was unknown. I wonder if that 0.0 percent was rounded from 1 in ten-thousand, or was definitely 0. Last observation seems to be January 8, well before its Mars encounter.

01101001
2009-Jun-02, 05:33 AM
will 2007 WD5 come back to mars ?

How many years do they take to return ?

Do you know where it is? Do you assume we know?

Current close approach data, though I'm not sure it's been tracked after its recent close approach, is at JPL Small-Body Database (http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007%20WD5;orb=1;cov=0;log=0;cad=1#c ad). Oh, that's historical only. They haven't predicted the future -- probably because they don't know.

Jens
2009-Jun-02, 05:49 AM
The reason that I said ..changed direction at last hour ....was becouse it seems a little Interesting that the 1 in 75 chance did not happen .


I can't believe that you are seriously saying this. Even if the chances were as high as 1 in 75, it is still a very low chance, less than 2%.

Paul Beardsley
2009-Jun-02, 06:36 AM
I recall catching the end of the film Dumb and Dumber, when one of the dumb characters declared his love for the beautiful woman. However, she was a) happily married and b) even if she hadn't been, she had no interest whatsoever in this dumb bloke. But when she told him the chances of them ever getting together were 3 million to one against, he was happy because at least there was one chance in 3 million.

NickW
2009-Jun-02, 06:53 AM
"So your telling me there's a chance......YEAH!"

slang
2009-Jun-02, 07:03 AM
It didn't hit Mars because we sent Beagle 2 to crash into it, to save Mars. Payback for them saving us from Tunguska, 'n all that.

novaderrik
2009-Jun-02, 08:27 AM
I recall catching the end of the film Dumb and Dumber, when one of the dumb characters declared his love for the beautiful woman. However, she was a) happily married and b) even if she hadn't been, she had no interest whatsoever in this dumb bloke. But when she told him the chances of them ever getting together were 3 million to one against, he was happy because at least there was one chance in 3 million.

it's something like this:
Jim Carrey: what are the odds of a guy like you and a girl like me getting together? 1 in 10? 1 in 100?
Lauren Holley: more like 1 in a million
Jim Carrey: so you're saying there's a chance.

Swift
2009-Jun-02, 12:13 PM
I thought that the Asteroid Had 1 in 75 Odds to Hit Mars ?

1 in 75 chance is not easy to get these days ?

You would need to go way back to even have that good of a chance to for a planet to have that great of a chance to be hit.

The reason that I said ..changed direction at last hour ....was becouse it seems a little Interesting that the 1 in 75 chance did not happen .

Maybe the direction could have changed by the moon of mars
I suspect your confusion is because of what it means that the asteroid had a 1 in 75 chance of hitting Mars. It has to do with the precision with which the orbit was calculated. Given the data that was available at the time, there was a significant error in that calculation. Error was large enough that they could not be sure exactly where it was going to go. The asteroid followed the path it was going to follow - nothing changed. We just didn't know for certain if that path was going to intersect Mars.

Gandalf223
2009-Jun-02, 03:20 PM
will 2007 WD5 come back to mars ?
How many years do they take to return ?

Using NASA's orbital predictions for 2007 WD5 from before the Mars encounter in January, it would return and pass Mars' orbit in June 2011. It would then pass approximately 0.65 AU from Earth about July 28, 2011.

YES, those predictions may not be entirely correct, because the asteroid passed close enough to Mars that its orbit may have been perturbed. However, Mars' gravity is not strong enough nor did it pass closely enough for the effect to be massive. IOW, the predictions are probably still not far off.


How do you know it missed?
Edit: Never mind. I found one.

Astronomers Rule Out Possibility of Asteroid Impact on Mars (http://www.jpl.nasa.gov/news/news.cfm?release=2007-152)

Edit: I wonder if that 0.0 percent was rounded from 1 in ten-thousand, or was definitely 0.

From the above link:
Updated Jan 9, 2008 As expected, scientists at JPL's Near-Earth Object Office have further refined the trajectory estimate for asteroid 2007 WD5 and ruled out any possibility of a Mars impact on Jan. 30. The latest trajectory plot of the asteroid was made possible by adding to previously obtained data some new data from a round of observations acquired by three observatories on the evenings of Jan. 5 through 8. Based on this latest analysis, the odds for the asteroid impacting Mars on Jan. 30 are 0.0 percent.Those folks are a lot smarter than any of the CT'ers and doomsayers give them credit for.

Zero point zero is good enough for me. It missed.

NEOWatcher
2009-Jun-02, 05:01 PM
Did anyone notice if Mars was as big as a full moon that night?

Mars might have just jumped out of the way.

Jens
2009-Jun-03, 04:46 AM
Mars might have just jumped out of the way.

Or maybe Nibiru came charging through and deflected it.

NEOWatcher
2009-Jun-03, 01:02 PM
Or maybe Nibiru came charging through and deflected it.
That joke's not as effective since Gandalf mentioned it.

I was trying for the inside joke mentioned on this thread's (http://www.bautforum.com/1492260-post1.html) diagram.

thoth II
2009-Jun-03, 06:51 PM
but see we have so many human made objects on mars there would have been a Picture of it by now ? Not only that but I am sure some place someone had there scope on it ...

I don't think it is as simple as assuming that. I'm sure many thousands of meteorites crash into earth, into the oceans, and are never detected by any satellite or telescope.

On Mars, there are probably many events occurring we can't see with the arrays of Mars orbital satellites and earth bound telescopes.

Celestial Mechanic
2009-Jun-03, 07:12 PM
I don't think it is as simple as assuming that. I'm sure many thousands of meteorites crash into earth, into the oceans, and are never detected by any satellite or telescope.

On Mars, there are probably many events occurring we can't see with the arrays of Mars orbital satellites and earth bound telescopes.Don't forget, there are thousands of times as many satellites in orbit and telescopes on the ground on Earth than there are on Mars, and still we don't detect every single meteor capable of making it to the ground.

rommel543
2009-Jun-03, 07:34 PM
How ? what made it change its direction at the last hour

If I'm doing the math correctly (which I am probably not), if you just took the distance between the earth and the moon and were 1 degree off it would be a distance of over 6500 km. Now I'm sure the uber-smart people at JPL could get the trajectory much closer in accuracy than 1 degree, but you can see how small changes in the trajectory can cause BIG differences in the chance of hitting an object. Now when you take a small, oddly shaped object like 2007 WD5, spinning in space with solar wind pushing on it, and attempting to determine where it's going to pass exactly in a couple million km, a 1 in 75 is a pretty good measurement. As 2007 WD5 got closer to Mars they could measure more accurately and thus the chances of hitting decreased until they became 0.

01101001
2009-Jun-03, 08:05 PM
Follow the JPL NEO Program press releases over time:

Mars Impact Probability Increases to 4 Percent (NASA - December 28, 2007) (http://neo.jpl.nasa.gov/news/news153.html)
New Observations Slightly Decrease Mars Impact Probability (NASA - January 2, 2008) (http://neo.jpl.nasa.gov/news/news154.html)
Mars Impact Seems Less Likely (NASA - January 8, 2008) (http://neo.jpl.nasa.gov/news/news155.html)
2007 WD5 Mars Collision Effectively Ruled Out - Impact Odds now 1 in 10,000 (NASA - January 8, 2008) (http://neo.jpl.nasa.gov/news/news156.html)

Observe the object's uncertainty region shrink, observation by observation, until it no longer included any bit of Mars.

WD5 didn't change. Our knowledge of it did.

rommel543
2009-Jun-03, 08:23 PM
Follow the JPL NEO Program press releases over time:

Mars Impact Probability Increases to 4 Percent (NASA - December 28, 2007) (http://neo.jpl.nasa.gov/news/news153.html)
New Observations Slightly Decrease Mars Impact Probability (NASA - January 2, 2008) (http://neo.jpl.nasa.gov/news/news154.html)
Mars Impact Seems Less Likely (NASA - January 8, 2008) (http://neo.jpl.nasa.gov/news/news155.html)
2007 WD5 Mars Collision Effectively Ruled Out - Impact Odds now 1 in 10,000 (NASA - January 8, 2008) (http://neo.jpl.nasa.gov/news/news156.html)

Observe the object's uncertainty region shrink, observation by observation, until it no longer included any bit of Mars.

WD5 didn't change. Our knowledge of it did.

In the last linked page there was this comment below one of the pictures (my bold):


Image of 2007 WD5 from the University of Hawaii 2.2-meter telescope on Mauna Kea, Hawaii. The circled dot is the asteroid. Other dots are artifacts from cosmic rays. The stars are trailed because the telescope is tracking the asteroid as it moves among the stars. (Credit: Tholen, Bernardi, Micheli with support from the National Science Foundation).

I've never known that the cosmic rays would show up in astral-photography before. I've seen star trails from long exposures but never cosmic rays, that I know of. Is it because the height that they're at? When you look at Keck photos (same location) or Hubble photos you don't see that.

01101001
2009-Jun-03, 11:37 PM
I've never known that the cosmic rays would show up in astral-photography before. I've seen star trails from long exposures but never cosmic rays, that I know of.

All the time. It's in the Cassini FAQ as I recall. People see them all the time in the MER and Phoenix images and think they're seeing structures.

I'll find some references:

SOHO Hotshot: HOW TO MAKE YOUR OWN UFO (http://sohowww.nascom.nasa.gov/hotshots/2003_01_17/)

CASSINI IMAGING SCIENCE: INSTRUMENT CHARACTERISTICS [...] (http://ciclops.org/sci/docs/CassiniImagingScience.pdf) page 115 (PDF, 4 megabyte) (Article in topic Phoenix Photo Mystery (http://www.bautforum.com/space-astronomy-questions-answers/74877-phoenix-photo-mystery.html#post1255989) excerpts a sample image from the PDF and links to other cosmic-ray material.)

Cassini Raw Images FAQ (http://saturn.jpl.nasa.gov/faq/FAQRawImages/#q6):


What are those streaks I see in some images?
There are high-energy particles that fly though space called cosmic rays. When one of these particles hit the camera's sensor, it causes a bright spot. When one of the particles hit the camera's sensor edge-on, it can leave a trail across the image. Exposures shorter than a second will not have many of these spots or trails. However, long exposures, like those from a minute to 20 minutes will contain many of these trails.

Cosmic Rays and Other Nonsense in Astronomical CCD Imagers (http://snap.lbl.gov/ccdweb/groom.pdf) (involving Earth-based imagers)


The ability of ionizing radiation to generate electron-hole pairs in sil-
icon is the bane of optical astronomy, where "cosmic rays" contribute
confusion and loss of imaging pixels in CCD's. Multiple exposures and
elaborate software are used to eliminate these artifacts.
[...]
We have made a study of these events, in most (but not all) cases in
totally depleted LBNL CCD's [1] 200-300 micrometer thick. Long dark images
were obtained under dierent conditions at a variety of places: The
UCO/Lick and NOAO CCD laboratories, in a low-background room at
LBNL, deep underground at Oroville, CA, at Kitt Peak, Cerro Tololo,
the Keck, and Lick Observatory. Here we explore the nature of the
events and the use of lead shielding to reduce the number of spots and
worms.

Keywords: cosmic ray hits ccd cassini faq soho mer rover phoenix telescope

Don Alexander
2009-Jun-03, 11:56 PM
When you look at Keck photos (same location) or Hubble photos you don't see that.
That's because those images are processed to all hell and back. Dark-subtracted, flatfielded, stacked with minmax-cutting, maybe had LACosmic run over them... (Not to mention false colors and whatnot...)

It's very rare that astronomical images in their RAW form are presented to the public.

slang
2009-Jun-04, 06:57 AM
On Mars, there are probably many events occurring we can't see with the arrays of Mars orbital satellites and earth bound telescopes.

Wikipedia: Astronomy on Mars (http://en.wikipedia.org/wiki/Astronomy_on_Mars). There are more images of possible meteors (and/or cosmic rays) on Mars.

rommel543
2009-Jun-04, 08:33 PM
All the time. It's in the Cassini FAQ as I recall. People see them all the time in the MER and Phoenix images and think they're seeing structures.

I'll find some references:

SOHO Hotshot: HOW TO MAKE YOUR OWN UFO (http://sohowww.nascom.nasa.gov/hotshots/2003_01_17/)


I've been on SOHO numerous times and seen the 'noise' occurring in the images. I aways thought it was solar radiation affecting the imaging equipment or the transmissions, not cosmic radiation hitting the CCD.