Full Version: Asteroid on track for possible Mars hit
What are the chances of the asteroid being "bound" to impact Mars, if the asteroid won't hit now, but it's orbit being adapted so a future impact is unavoidable?
QUOTE (CAP-Team @ Dec 30 2007, 12:50 PM) 
What are the chances of the asteroid being "bound" to impact Mars, if the asteroid won't hit now, but it's orbit being adapted so a future impact is unavoidable?
I know this is a dodge, since someone with more knowledge on orbital mechanics could give a vague range of percentages, but I'd say that it's not even worth calculating until after the 30th. The effect of Mars' gravity on the future trajectory will depend on how close this approach actually turns out to be. These are the times when the uncertainties show high nonlinear behavior, as a tiny difference in this Mars close approach will make a huge difference down the road.
Maybe we get an atmospheric graze like the Jackson Lake bolide back in the seventies.
{is it still a bolide if it happens at Mars ?? I forget so many things these days . . . }
{is it still a bolide if it happens at Mars ?? I forget so many things these days . . . }
Does any one have a clue how much of a boom can this thing inflict?
(if it were to hit Mars
)
(if it were to hit Mars
)
Doc - a good place to go to get an idea of how big a bang an impactor can cause is H Jay Melosh and Ross A. Beyer's Crater size calculator at LPL.When you select appropriate numbers for this object (50m diameter composed of loose rock, asteroid impact at mars hitting a porous rock surface) you get somewhere between a 700m and 1.8 km diameter crater. The impact energy released is on the order of 1.2 MegaTons.
QUOTE (helvick @ Dec 31 2007, 09:07 PM)
Doc - a good place to go to get an idea of how big a bang an impactor can cause is H Jay Melosh and Ross A. Beyer's Crater size calculator at LPL.When you select appropriate numbers for this object (50m diameter composed of loose rock, asteroid impact at mars hitting a porous rock surface) you get somewhere between a 700m and 1.8 km diameter crater. The impact energy released is on the order of 1.2 MegaTons.
I tried putting the numbers you gave through H Jay Melosh & Gareth Collins Earth Impact Effects Program, turns out if this object hit the Earth it would airburst at 42400 ft... which is not much good for figuring out just what it would do at Mars.
Though if you do want to have some fun with this one, just put in the following:
Projectile Dia: 10km
Density: Porous Rock.
Impact: 17kms
and have it impact into sedimentary rock at 45 degrees. You'll get a rough idea of what happened to the dinosaurs... just make sure you are well away from the impact yourself (3000km).
QUOTE (gndonald @ Dec 31 2007, 05:11 PM)
I tried putting the numbers you gave through H Jay Melosh & Gareth Collins Earth Impact Effects Program, turns out if this object hit the Earth it would airburst at 42400 ft... which is not much good for figuring out just what it would do at Mars.
Pity...... oh well, at least the odds have become more favourable. Least to say it will (hopefully) be a once in a life time opportunity. Lets wait and see
QUOTE (gndonald @ Dec 31 2007, 04:11 AM)
not much good for figuring out just what it would do at Mars.
gn,
The crater size calculator offers options for Mars impacts. You just didn't choose them.
I'm rooting for an impact near a MER (however unlikely that may be). I think of the old US Civil War adage that to kill a man you needed a mass of bullets about equal to the man. The vicinity of the MER would have to be absolutely machine-gunned for a "kill" to be likely. A huge impactor might machine gun an entire region of Mars (dropping at least one secondary onto every single square meter), but this won't be a huge impactor.
If a MER can resolve an area equal to about 100 times the area of the MER itself, then we'd have far better odds of one secondary dropping within range (so it could be examined) vs. the odds of the MER itself taking a kill shot. Bring it on!
If a MER can resolve an area equal to about 100 times the area of the MER itself, then we'd have far better odds of one secondary dropping within range (so it could be examined) vs. the odds of the MER itself taking a kill shot. Bring it on!
QUOTE (Shaka @ Jan 1 2008, 06:07 AM)
gn,
The crater size calculator offers options for Mars impacts. You just didn't choose them.
The crater size calculator offers options for Mars impacts. You just didn't choose them.
Actually I was using a completely different program which was optimized to determine the impact effects of an asteroid on Earth, the Crater program is a completely different setup which only deals with the size of the crater after impact, that's not to say both produce interesting results.
One of the more sobering for me was when I ran the impact effects calculator using the Chicxulub impacter stats but having the thing hit the ground where the Wolf Creek crater was. It turns out that I probably would not survive down in Perth. It's not the impact but rather the blast wave that gets you....
Edit: I've found a simple online program that gives some idea of the ground shaking this asteroid might cause. Assuming it hits with a speed of 20km/s then it produces a 6.2 on the Richter scale.
QUOTE (gndonald @ Jan 1 2008, 05:04 AM)
Actually I was using a completely different program which was optimized to determine the impact effects of an asteroid on Earth,
I think the estimate from this, if accurate, indicates that a 50m diameter asteroid will probably make it to the Martian surface and the energy of the impact will remain substantially the same as those produced by the Crater calculator.
The Impact Effects results you link to put the initial breakup in the Earth case at around 65km with the air burst at 7km dissipating 95% of the original kinetic energy. In the Martian case the entire atmospheric column is less massive than the part on Earth that is above 65km so it seems reasonable to infer that it should reach the surface (mostly) intact and with the majority of its kinetic energy remaining.
That is if it does actually hit which remains quite a long shot.
.
QUOTE (Moon Saloon @ Jan 1 2008, 11:59 AM)
Can MRO be used to improve the orbit knowledge?
No, because the asteroid is coming from the direction of the Sun relative to Mars. There is too much glare. Only ground based observations can give us better constraints upon the orbit of 2007 WD5 until it passes Mars--or Hubble.
How great would this be if it did hit? It would be like having a free Deep Impact/LCROSS, but for Mars!
A few new observations of the asteroid have finally been reported, taken within the last 40 hours by Magalena Ridge Observatory. The reported results are a little confusing.
Apparently there is still some small chance it will impact. The nominal miss distance from Mars center is given as about 24000 miles (or roughly 38000km). The minimum possible is 1600 miles, which is below the surface.
However, the error ellipse as viewed from Earth at that time shows a possible tracking error of only 5.87 arc seconds, according to the generated ephemeris.
This would be a clear miss, as Mars itself is over 16 arc seconds big at that point. Perhaps the ephemeris is operating at a lower (90 per cent? 95 per cent?) probability.
Link
Apparently there is still some small chance it will impact. The nominal miss distance from Mars center is given as about 24000 miles (or roughly 38000km). The minimum possible is 1600 miles, which is below the surface.
However, the error ellipse as viewed from Earth at that time shows a possible tracking error of only 5.87 arc seconds, according to the generated ephemeris.
This would be a clear miss, as Mars itself is over 16 arc seconds big at that point. Perhaps the ephemeris is operating at a lower (90 per cent? 95 per cent?) probability.
Link
The tracking error and the orbital trajectory are two separate issues. The tracking error of 5.87 secs is the error in actually plotting the asteroid in 3d space. This one measurement alone says nothing about the movement of the object. We determine the trajectory by plotting all of the observations together...to track the movement over time. Only a few observations greatly compounds the possible errors. If you have more observations, then the errors tend to gradually cancel eachother out. But you need a significant number of observations for the 'Law of Large Numbers' to have a statistical effect on the results. 30 or so observations are simply not nearly enough. I'd give it another week or maybe two for additional observations before we have any significant confidence in the numbers (that's probably multiple observations per day).
Law of Large Numbers says the uncertainity should decline with the square root of the number of observations, all other things being equal, so to cut that tracking error in half, it'll take about another 100 observations.
Of course if the new observations use a different technique, they could do much better than that. Also, the LLN only applies if the obervations are independent and identically distributed, and I suspect these are neither. :-)
--Greg
Of course if the new observations use a different technique, they could do much better than that. Also, the LLN only applies if the obervations are independent and identically distributed, and I suspect these are neither. :-)
--Greg
First a correction. I stated in my previous post that Mars would appear larger than 16 arc secs at the end of the month. It is actually going to be 12.3 arc secs as viewed from Earth. Not sure where I messed up on that one, but sorry.
The tracking error I referred to earlier is the uncertainty ellipse of where you would find the asteroid in the sky as viewed from some point on Earth. This is what is generated on the ephemeris on the NeoDys web site, and is located on the far right of the generated table of predicted positions for a particular asteroid over a given time interval.
My apologies if I wasn't clear about what I was referencing earlier. This tracking error is a two dimensional figure on the sky, not a three dimensional location in space. It says that on January 30th, the predicted position of 2007 WD5 on the sky could be in error by about six arc sec. In this case, that is mostly in two opposite directions along a very narrow ellipse (almost a line, which intersects the planet if you extend it a little).
Now, I've looked into it a little more. The sky error is only a one sigma approximation. NeoDys themselves recommend that you multiply that uncertainty by at least three to be more certain of actually locating something with a high degree of confidence.
As for getting multiple observations per day, that is a forlorn hope. The resources don't exist for an object this faint. Well, actually they do, but they're all booked up for other things.
But we only need a few more looks anyway. As the date fast approaches, and we can spot where this rock actually is in relation to Mars, we will see the error box collapse rapidly.
The tracking error I referred to earlier is the uncertainty ellipse of where you would find the asteroid in the sky as viewed from some point on Earth. This is what is generated on the ephemeris on the NeoDys web site, and is located on the far right of the generated table of predicted positions for a particular asteroid over a given time interval.
My apologies if I wasn't clear about what I was referencing earlier. This tracking error is a two dimensional figure on the sky, not a three dimensional location in space. It says that on January 30th, the predicted position of 2007 WD5 on the sky could be in error by about six arc sec. In this case, that is mostly in two opposite directions along a very narrow ellipse (almost a line, which intersects the planet if you extend it a little).
Now, I've looked into it a little more. The sky error is only a one sigma approximation. NeoDys themselves recommend that you multiply that uncertainty by at least three to be more certain of actually locating something with a high degree of confidence.
As for getting multiple observations per day, that is a forlorn hope. The resources don't exist for an object this faint. Well, actually they do, but they're all booked up for other things.
But we only need a few more looks anyway. As the date fast approaches, and we can spot where this rock actually is in relation to Mars, we will see the error box collapse rapidly.
To what extent, if any, are the calculations taking into account Mars' gravity well when the asteroid is closer? Mars may just barely fall inside the error ellipse but are these projections so far just about calculating the objects path from known observations or are they factoring in any attraction caused by Mars' gravity. How close would it have to get to be 'sucked in'? How close to be greatly deflected along a new path (but no collision)?
Yes, martian gravity is being taken into account. Small errors in the location of this asteroid when nearest Mars translate into very significant differences in the deflection of the orbit. If you carry the ephemeris forward a few days into February, you will see that the sky error dramatically increases after the close approach, assuming there is an "after". But at this point, that's a fairly safe assumption.
Here's a new Horizon ephemeris for the pass of asteroid 2007 WD5 over the Spirit site. I've added a new column to the output with Local Apparent Solar Time (which differs slightly from the Mean Solar Time JPL's MER team uses).
Steve M
Steve M
CODE
Target body name: (2007 WD5) {source: JPL#8}
Center body name: Mars (499) {source: DE405}
Center-site name: Spirit Landing Site (MER) / Gusev
*******************************************************************************
Start time : A.D. 2008-Jan-30 11:00:00.0000 UT
Stop time : A.D. 2008-Jan-30 14:00:00.0000 UT
Step-size : 10 minutes
*******************************************************************************
Target pole/equ : No model available
Target radii : (unavailable)
Center geodetic : -175.48330,-14.566677,-.0066762 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: -175.48330,3288.23600,-844.4501 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : IAU_MARS {East-longitude -}
Center radii : 3396.2 x 3396.2 x 3376.2 km {Equator, meridian, pole}
Target primary : Sun {source: DE405}
Interfering body: PHOBOS (Req= 13.400) km {source: MAR063}
Deflecting body : Sun, MARS {source: DE405}
Deflecting GMs : 1.3271E+11, 4.2828E+04 km^3/s^2
Small perturbers: Ceres, Pallas, Vesta {source: SB405-CPV-2}
Small body GMs : 6.32E+01, 1.43E+01, 1.78E+01 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
RTS-only print : NO
EOP file : eop.080101.p080324
EOP coverage : DATA-BASED 1962-JAN-20 TO 2008-JAN-01. PREDICTS-> 2008-MAR-23
Units conversion: 1 AU= 149597870.691 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass n.a. , Daylight (NO )
Table cut-offs 2: Solar Elongation ( 0.0,180.0=NO )
*******************************************************************************
Initial FK5/J2000.0 heliocentric ecliptic osculating elements (AU, DAYS, DEG):
EPOCH= 2454434.5 ! 2007-Nov-30.00 (CT) Residual RMS= .27399
EC= .6029126939128898 QR= 1.010155286144832 TP= 2454392.142635427
OM= 67.42380154980685 W= 312.8217042008886 IN= 2.377011213076177
Asteroid physical parameters (KM, SEC, rotational period in hours):
GM= n.a. RAD= n.a. ROTPER= n.a.
H= 24.336 G= .150 B-V= n.a.
ALBEDO= n.a. STYP= n.a.
*********************************************************************
Date__(UT)__HR:MN R.A._(ICRF/J2000.0)_DEC Azi_(a-appr)_Elev APmag delta deldot L_Ap_SOL_Time
*********************************************************************
$$SOE
2008-Jan-30 11:00 17 32 37.75 -28 21 06.3 104.1778 -31.5508 n.a. .000460072319574 -11.1156163 02 15 53.6700
2008-Jan-30 11:10 17 17 19.90 -28 19 00.0 103.9278 -25.9495 n.a. .000416184992425 -10.7501418 02 25 37.7592
2008-Jan-30 11:20 16 58 31.63 -28 07 29.7 103.8917 -19.5825 n.a. .000374023608028 -10.2464432 02 35 21.8486
2008-Jan-30 11:30 16 35 13.15 -27 39 35.8 104.1159 -12.2139 n.a. .000334262329453 -9.5406128 02 45 05.9383
2008-Jan-30 11:40 16 06 16.14 -26 43 51.2 104.6810 -3.5471 n.a. .000297886894691 -8.5401645 02 54 50.0281
2008-Jan-30 11:50 r 15 30 40.09 -25 03 02.4 105.7268 6.7421 n.a. .000266314303252 -7.1239818 03 04 34.1182
2008-Jan-30 12:00 14 48 11.03 -22 15 54.4 107.5081 18.8801 11.87 .000241464314346 -5.1715824 03 14 18.2084
2008-Jan-30 12:10 14 00 16.90 -18 07 18.0 110.5258 32.7221 11.00 .000225598430869 -2.6539639 03 24 02.2990
2008-Jan-30 12:20 13 10 30.03 -12 46 37.4 115.8787 47.4169 10.33 .000220689063986 0.2383794 03 33 46.3898
2008-Jan-30 12:30 12 23 15.57 -06 55 15.8 126.3293 61.3195 9.89 .000227466867097 3.0990608 03 43 30.4808
2008-Jan-30 12:40 11 41 48.43 -01 24 01.0 149.2184 71.9874 9.67 .000244977003702 5.5431073 03 53 14.5722
2008-Jan-30 12:50 t 11 07 17.42 +03 16 04.3 191.0093 75.5431 9.60 .000271156362793 7.4178189 04 02 58.6638
2008-Jan-30 13:00 10 39 17.83 +06 58 48.0 224.1826 71.5851 9.62 .000303776954115 8.7734747 04 12 42.7557
2008-Jan-30 13:10 10 16 46.14 +09 51 32.6 239.5451 65.3006 9.69 .000340998830652 9.7339015 04 22 26.8479
2008-Jan-30 13:20 x 09 58 34.80 +12 05 07.9 246.9795 59.0609 9.80 .000381480283317 10.4161770 04 32 10.9404
2008-Jan-30 13:30 x 09 43 45.91 +13 49 19.1 251.0525 53.3308 9.92 .000424291592808 10.9078364 04 41 55.0332
2008-Jan-30 13:40 x 09 31 33.90 +15 11 40.8 253.4802 48.1280 10.04 .000468796659878 11.2689096 04 51 39.1263
2008-Jan-30 13:50 x 09 21 24.10 +16 17 46.8 254.9965 43.3796 10.17 .000514557497950 11.5394226 05 01 23.2198
2008-Jan-30 14:00 x 09 12 50.38 +17 11 37.9 255.9586 39.0048 10.29 .000561267913255 11.7460149 05 11 07.3136
Center body name: Mars (499) {source: DE405}
Center-site name: Spirit Landing Site (MER) / Gusev
*******************************************************************************
Start time : A.D. 2008-Jan-30 11:00:00.0000 UT
Stop time : A.D. 2008-Jan-30 14:00:00.0000 UT
Step-size : 10 minutes
*******************************************************************************
Target pole/equ : No model available
Target radii : (unavailable)
Center geodetic : -175.48330,-14.566677,-.0066762 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: -175.48330,3288.23600,-844.4501 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : IAU_MARS {East-longitude -}
Center radii : 3396.2 x 3396.2 x 3376.2 km {Equator, meridian, pole}
Target primary : Sun {source: DE405}
Interfering body: PHOBOS (Req= 13.400) km {source: MAR063}
Deflecting body : Sun, MARS {source: DE405}
Deflecting GMs : 1.3271E+11, 4.2828E+04 km^3/s^2
Small perturbers: Ceres, Pallas, Vesta {source: SB405-CPV-2}
Small body GMs : 6.32E+01, 1.43E+01, 1.78E+01 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
RTS-only print : NO
EOP file : eop.080101.p080324
EOP coverage : DATA-BASED 1962-JAN-20 TO 2008-JAN-01. PREDICTS-> 2008-MAR-23
Units conversion: 1 AU= 149597870.691 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass n.a. , Daylight (NO )
Table cut-offs 2: Solar Elongation ( 0.0,180.0=NO )
*******************************************************************************
Initial FK5/J2000.0 heliocentric ecliptic osculating elements (AU, DAYS, DEG):
EPOCH= 2454434.5 ! 2007-Nov-30.00 (CT) Residual RMS= .27399
EC= .6029126939128898 QR= 1.010155286144832 TP= 2454392.142635427
OM= 67.42380154980685 W= 312.8217042008886 IN= 2.377011213076177
Asteroid physical parameters (KM, SEC, rotational period in hours):
GM= n.a. RAD= n.a. ROTPER= n.a.
H= 24.336 G= .150 B-V= n.a.
ALBEDO= n.a. STYP= n.a.
*********************************************************************
Date__(UT)__HR:MN R.A._(ICRF/J2000.0)_DEC Azi_(a-appr)_Elev APmag delta deldot L_Ap_SOL_Time
*********************************************************************
$$SOE
2008-Jan-30 11:00 17 32 37.75 -28 21 06.3 104.1778 -31.5508 n.a. .000460072319574 -11.1156163 02 15 53.6700
2008-Jan-30 11:10 17 17 19.90 -28 19 00.0 103.9278 -25.9495 n.a. .000416184992425 -10.7501418 02 25 37.7592
2008-Jan-30 11:20 16 58 31.63 -28 07 29.7 103.8917 -19.5825 n.a. .000374023608028 -10.2464432 02 35 21.8486
2008-Jan-30 11:30 16 35 13.15 -27 39 35.8 104.1159 -12.2139 n.a. .000334262329453 -9.5406128 02 45 05.9383
2008-Jan-30 11:40 16 06 16.14 -26 43 51.2 104.6810 -3.5471 n.a. .000297886894691 -8.5401645 02 54 50.0281
2008-Jan-30 11:50 r 15 30 40.09 -25 03 02.4 105.7268 6.7421 n.a. .000266314303252 -7.1239818 03 04 34.1182
2008-Jan-30 12:00 14 48 11.03 -22 15 54.4 107.5081 18.8801 11.87 .000241464314346 -5.1715824 03 14 18.2084
2008-Jan-30 12:10 14 00 16.90 -18 07 18.0 110.5258 32.7221 11.00 .000225598430869 -2.6539639 03 24 02.2990
2008-Jan-30 12:20 13 10 30.03 -12 46 37.4 115.8787 47.4169 10.33 .000220689063986 0.2383794 03 33 46.3898
2008-Jan-30 12:30 12 23 15.57 -06 55 15.8 126.3293 61.3195 9.89 .000227466867097 3.0990608 03 43 30.4808
2008-Jan-30 12:40 11 41 48.43 -01 24 01.0 149.2184 71.9874 9.67 .000244977003702 5.5431073 03 53 14.5722
2008-Jan-30 12:50 t 11 07 17.42 +03 16 04.3 191.0093 75.5431 9.60 .000271156362793 7.4178189 04 02 58.6638
2008-Jan-30 13:00 10 39 17.83 +06 58 48.0 224.1826 71.5851 9.62 .000303776954115 8.7734747 04 12 42.7557
2008-Jan-30 13:10 10 16 46.14 +09 51 32.6 239.5451 65.3006 9.69 .000340998830652 9.7339015 04 22 26.8479
2008-Jan-30 13:20 x 09 58 34.80 +12 05 07.9 246.9795 59.0609 9.80 .000381480283317 10.4161770 04 32 10.9404
2008-Jan-30 13:30 x 09 43 45.91 +13 49 19.1 251.0525 53.3308 9.92 .000424291592808 10.9078364 04 41 55.0332
2008-Jan-30 13:40 x 09 31 33.90 +15 11 40.8 253.4802 48.1280 10.04 .000468796659878 11.2689096 04 51 39.1263
2008-Jan-30 13:50 x 09 21 24.10 +16 17 46.8 254.9965 43.3796 10.17 .000514557497950 11.5394226 05 01 23.2198
2008-Jan-30 14:00 x 09 12 50.38 +17 11 37.9 255.9586 39.0048 10.29 .000561267913255 11.7460149 05 11 07.3136
I have a question also regarding the possible hit of this asteroid?
If they determine it is going to Hit Mars near Opportunity?
Will they drive Opportunity out of Victoria Crater to photograph the impact from a distance.
I think any additional images especially from ground level would have a lot of information in it?
Just Wondering
If they determine it is going to Hit Mars near Opportunity?
Will they drive Opportunity out of Victoria Crater to photograph the impact from a distance.
I think any additional images especially from ground level would have a lot of information in it?
Just Wondering
I doubt very much that even IF it hits (shoulda used a larger font for "if", because impact remains unlikely in the extreme) we'd have enough certainty regarding the impact location to make this possible.
In fact, as I stated in an earlier post, I strongly doubt that we'll even know if it does hit until several days afterwards at the earliest, unless the MER IMUs sense it. This is a pretty small rock, and tracking it during the terminal inbound & outbound phases is gonna be a few notches above 'challenging'...
In fact, as I stated in an earlier post, I strongly doubt that we'll even know if it does hit until several days afterwards at the earliest, unless the MER IMUs sense it. This is a pretty small rock, and tracking it during the terminal inbound & outbound phases is gonna be a few notches above 'challenging'...
Here's the source from which Marsdaily copied the story, which also has the diagram at a legible resolution.
New Observations Slightly Decrease Mars Impact Probability
--Emily
New Observations Slightly Decrease Mars Impact Probability
--Emily
QUOTE (nprev @ Dec 21 2007, 02:07 PM)
Yeah, 1 in 75 isn't great...but here's hoping for some serious luck!!! We have 3 active orbiters; there's never been a better time in history for this to happen!
I'm not as interested in seeing the actual impact itself as I am in seeing the resultant crater, which would be strong enough to expose some deeply buried materials that could be studied before the ubiquitous dust coats them...
I'm not as interested in seeing the actual impact itself as I am in seeing the resultant crater, which would be strong enough to expose some deeply buried materials that could be studied before the ubiquitous dust coats them...
I'm not as interested in seeing the actual impact itself as I am in seeing the resultant faces of some polititians when they realize such a thing can hit them at any time...
They don't care! If they cared, any of them, they'd have put money into searches etc before now, after SL9 gave Jupiter a good slap in '94. It's one of those things that's just a "theoretical possibility" to them, right up there along with global warming and the chance they might give a straight answer to a straight question...
But that's getting into politics, sorry Admins. My bad. Thing is, this impact - if it happens - will only excite scientists and science enthusiasts like ourselves, here on t'internet and in the real world's astronomy and science magazines. For everyone else, even if the asteroid chunk somehow blasted a 10km wide crater into Mars, it would be a news item to be splashed across the tabloids' front pages with a suitably lurid headline, and tagged on the end of the TV news shows - reported by a giggly I-wear-my-ignorance-about-science-like-a-medal bubblehead or a sneering, square-jawed, Grecian 2000-dyed "oh man, look what those excited geeky scientists are all excited about THIS time!" anchorman, illustrated with clips from Armageddon or Deep Impact, and linked with sound bites that are about as scientifically accurate as the script of the original "Lost in Space".
Part of me is actually hoping it misses, you know? I don't know if I could stand the Impact Day's awful reporting and the political sidewinding that would follow.
But the bigger part of me is still hoping we see something amazing soon after the 30th.
But that's getting into politics, sorry Admins. My bad. Thing is, this impact - if it happens - will only excite scientists and science enthusiasts like ourselves, here on t'internet and in the real world's astronomy and science magazines. For everyone else, even if the asteroid chunk somehow blasted a 10km wide crater into Mars, it would be a news item to be splashed across the tabloids' front pages with a suitably lurid headline, and tagged on the end of the TV news shows - reported by a giggly I-wear-my-ignorance-about-science-like-a-medal bubblehead or a sneering, square-jawed, Grecian 2000-dyed "oh man, look what those excited geeky scientists are all excited about THIS time!" anchorman, illustrated with clips from Armageddon or Deep Impact, and linked with sound bites that are about as scientifically accurate as the script of the original "Lost in Space".
Part of me is actually hoping it misses, you know? I don't know if I could stand the Impact Day's awful reporting and the political sidewinding that would follow.
But the bigger part of me is still hoping we see something amazing soon after the 30th.
Stu - with your (likely accurate) description of the news' probable treatment of this impact, I think I wept inside just a little bit. Science brought us the modern world as we know it. Let's make fun of it!
Darn on this decrease in impact probability. That would have been especially neat to get a good picture of the crater from HIRISE.
Darn on this decrease in impact probability. That would have been especially neat to get a good picture of the crater from HIRISE.
QUOTE (Stu @ Jan 4 2008, 05:23 PM)
will only excite scientists and science enthusiasts like ourselves, here on t'internet and in the real world's astronomy and science magazines.
I was working at a small ISP when the SL9 impact occured. The minutes used by our customers during that period leaped as
everyone was downloading images.
I think the SL9 event touched a broader spectrum of people and had to have made most of them think about the implications.
Another impact event would similarly draw interest and reinforce those that viewed the first one.
We'd have a large group of people that witnessed two massive impact events in their lifetime! Not just scientists.
Stu, this is from the Pan-STARRS site: http://pan-starrs.ifa.hawaii.edu/public/as...oid_threat.html
"Most of the asteroids and comets in our solar system pose no danger to our planet. But, for every thousand or so of those objects, there is one with an orbit crosses that of Earth, raising the possibility of a future collision. In 1991 the U.S. Congress directed NASA to conduct workshops on how potentially threatening asteroids could be detected, and how they could be deflected or destroyed. This mandate led to the Spaceguard Survey Report in 1992. In 1994 the House Committee on Science and Technology directed NASA, in coordination with the DOD, to work with the space agencies of other countries to identify and catalogue within 10 years the orbital characteristics of 90% of all comets and asteroids larger than 1 km and in orbits that cross the orbit of Earth."
I note that Pan-STARRS appears to be on schedule.
--Greg
"Most of the asteroids and comets in our solar system pose no danger to our planet. But, for every thousand or so of those objects, there is one with an orbit crosses that of Earth, raising the possibility of a future collision. In 1991 the U.S. Congress directed NASA to conduct workshops on how potentially threatening asteroids could be detected, and how they could be deflected or destroyed. This mandate led to the Spaceguard Survey Report in 1992. In 1994 the House Committee on Science and Technology directed NASA, in coordination with the DOD, to work with the space agencies of other countries to identify and catalogue within 10 years the orbital characteristics of 90% of all comets and asteroids larger than 1 km and in orbits that cross the orbit of Earth."
I note that Pan-STARRS appears to be on schedule.
--Greg
PANSTARRS-1 is in operation now in Haleakala. But the full-operation PANSTARRS (also refered to as PS-4) is facing an uncertain future. It should be located in Mauna Kea, but there's fierce opposition to the construction of any new telescopes in the Hawaiian islands by certain groups of natives.
In related news, LSST (an 8-m telescope designed to look for killer asteroids among other topics) is proceeding in its design and construction (it will be located in northern Chile) and just received a 30-million gift from Bill Gates and Charles Simonyi.
In related news, LSST (an 8-m telescope designed to look for killer asteroids among other topics) is proceeding in its design and construction (it will be located in northern Chile) and just received a 30-million gift from Bill Gates and Charles Simonyi.
QUOTE (MarsIsImportant @ Jan 1 2008, 10:22 AM)
No, because the asteroid is coming from the direction of the Sun relative to Mars. There is too much glare.
So don't look in that direction. (Learned from the Henny Youngman school of medicine: "Doctor, it hurts when I do this.", doctor: "Then don't do that!")
At closest approach it won't be in the Sun direction anyway, and just after the flyby, you'll be looking away from the Sun, with the object nicely lit by the Sun. After the flyby is when you really want to track it anyway, since errors before the flyby are amplified by the gravity assist.
Been doing some calculations on the effects of a possible impact (please, let it hit!).
If this impact produces a blast of 1.6 megatons then that would be equivalent to
more than 3,500,000,000 pounds of explosives. With reference to an seismicity explosives equivalent table, this is equivalent to a magnitude 6.5 to 7.0 earthquake
(similar to the one that hit Kobe, Japan in 1998). This is way beyond the Hiroshima bomb and such a boom is more than capable to cause significant mass wasting at Opportunity's site.
This is just an observation and is still at the mercy of the now falling chances for impact.
If this impact produces a blast of 1.6 megatons then that would be equivalent to
more than 3,500,000,000 pounds of explosives. With reference to an seismicity explosives equivalent table, this is equivalent to a magnitude 6.5 to 7.0 earthquake
(similar to the one that hit Kobe, Japan in 1998). This is way beyond the Hiroshima bomb and such a boom is more than capable to cause significant mass wasting at Opportunity's site.
This is just an observation and is still at the mercy of the now falling chances for impact.
Couple more observations reported now by Calar Alto Observatory.
The nominal miss distance has moved inward slightly toward Mars.
Apparently, there is still some possibility of an impact, although I have no idea what the odds are now.
And this baby keeps getting fainter and fainter, with fewer and fewer facilities able to spot it.
The nominal miss distance has moved inward slightly toward Mars.
Apparently, there is still some possibility of an impact, although I have no idea what the odds are now.
And this baby keeps getting fainter and fainter, with fewer and fewer facilities able to spot it.
From the NEO office, based on the 2 newest observations:
Mars Impact Seems Less Likely
As mentioned in the article, the miss distance isn't changing much with additional observations, but the cone is tightening.
Closest approaches in Horizons for the nominal solution are 30,366 km from the center of Mars at 2008-Jan-30 12:05.
Mars Impact Seems Less Likely
As mentioned in the article, the miss distance isn't changing much with additional observations, but the cone is tightening.
Closest approaches in Horizons for the nominal solution are 30,366 km from the center of Mars at 2008-Jan-30 12:05.
Well, a whole bunch of observations came in yesterday from three different sources.
I ain't gonna say it. Someone else can. I'm not sure if the messenger gets shot around here sometimes.
I ain't gonna say it. Someone else can. I'm not sure if the messenger gets shot around here sometimes.
QUOTE (Holder of the Two Leashes @ Jan 9 2008, 07:44 AM)
Well, a whole bunch of observations came in yesterday from three different sources.
I ain't gonna say it. Someone else can. I'm not sure if the messenger gets shot around here sometimes.
I ain't gonna say it. Someone else can. I'm not sure if the messenger gets shot around here sometimes.
Think it's pretty much an expectation at this point. Not good, from what I gather...still, everyone here knew damn good & well that the odds were very much against an impact.
OK, I'll spell it out.
M... i... s... s.
(Ducks and runs for cover).
M... i... s... s.
(Ducks and runs for cover).
It's going to hit Mississippi?
Maybe, or it might hit Oklahoma (hence the ducking and running for cover). This is both a Mars and Earth crosser. After this major deflection, no telling where it might eventually end up.
Given the historic importance of this rock, I'm hoping somebody will keep tracking it so it doesn't end up lost.
Given the historic importance of this rock, I'm hoping somebody will keep tracking it so it doesn't end up lost.
QUOTE (Holder of the Two Leashes @ Jan 9 2008, 07:02 PM)
M... i... s... s.
I don't think I'm ever going to get over this.......I think I need to *whack* something, then I'll feel better!
QUOTE (Holder of the Two Leashes @ Jan 10 2008, 04:12 PM)
1 in 10,000
<Dumb_And_Dumber>So you're saying there's a chance???</Dumb_And_Dumber>
Ah...better luck next time, still lots of rocks out there. C'est la vie.
Very disappointing. I was looking forward to an impact.
The odds drastically changed within 24 hours' time; early yesterday it was still a 1:40 chance and now it's 1:10,000. ::shrugs::
The odds drastically changed within 24 hours' time; early yesterday it was still a 1:40 chance and now it's 1:10,000. ::shrugs::
According to the article on Space.com the range of distances it will pass Mars is 4,000km - 26,000 km.
Meanwhile Phobos typically is about 9,400 km on its semi-major axis and Deimos is about 23,000 km.
I suppose the inclinations are all wrong and such. So can someone tell me when we can rule them out, if not immediately?
Meanwhile Phobos typically is about 9,400 km on its semi-major axis and Deimos is about 23,000 km.
I suppose the inclinations are all wrong and such. So can someone tell me when we can rule them out, if not immediately?
<pontification mode> I'd say the odds are in the billions or more, Dan. Phobos & Deimos are extremely small targets compared to Mars itself, and also have negligible gravitational fields; just ain't gonna happen, even if the orbital plane alignments were right, and the projected ground track over Mars makes me think that they're not; IIRC, both moons are in equatorial orbits. </pontification mode>
<honest mode!> Not trying to shoot you down at all, dude. I've noticed that 99% of what I predict is completely wrong, so thought I'd capitalize on this inverse luck...hit something, dammit!
</honest mode>
<honest mode!> Not trying to shoot you down at all, dude. I've noticed that 99% of what I predict is completely wrong, so thought I'd capitalize on this inverse luck...hit something, dammit!
</honest mode>
Agreed about the long odds, but obviously they have been impacted previously. I was just curious if anyone could rule out this body entirely.
QUOTE (nprev @ Jan 10 2008, 05:42 PM)
<honest mode!> Not trying to shoot you down at all, dude. I've noticed that 99% of what I predict is completely wrong, so thought I'd capitalize on this inverse luck...hit something, dammit! </honest mode>
</honest mode>There goes one of our orbiters.
OK, John -- now you've done it. Your comment made the following pop into my head:
Once there was a silly old rock,
Thought that it would clean Mars' clock.
But with a shove and a pull, that rock's stock
Says it won't go ker-plock!
But it has...
High hopes!
It has...
High hopes!
It has...
High, flying by
Deimos in the sky
Hopes!
So any time you're feeling low,
Feel like letting go,
Just remember that rock!
Ooops, there goes
A megaton of Mars shock!
-the other Doug
Once there was a silly old rock,
Thought that it would clean Mars' clock.
But with a shove and a pull, that rock's stock
Says it won't go ker-plock!
But it has...
High hopes!
It has...
High hopes!
It has...
High, flying by
Deimos in the sky
Hopes!
So any time you're feeling low,
Feel like letting go,
Just remember that rock!
Ooops, there goes
A megaton of Mars shock!
-the other Doug
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