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In this picture taken by Spirit early in the mission, you can see "Husband Hill" labeled as "E", about 3km away. It's on this hill right now. Opportunity has spent more time carefully looking around a dangerous crater instead of going for distance.

Sojourner only moved about 100 meters and was a huge success. Its most popular accomplishment was taking this picture before it even left the lander.

In this picture taken by Spirit early in the mission, you can see "Husband Hill" labeled as "E", about 3km away. It's on this hill right now. Opportunity has spent more time carefully looking around a dangerous crater instead of going for distance.

Sojourner only moved about 100 meters and was a huge success. Its most popular accomplishment was taking this picture before it even left the lander.

• 1 Opportunity
• P Pancam
• 155450047 Number of seconds since Jan 1, 2004 at 11:58::55.816. (works out to Sol 307)
• Data product full frame EDR

And no, I've not heard any comments on this picture yet. There are other pictures with frost, but water would be puzzling on the Martian surface at that pressure and temperature.

I'm pretty sure they'd have mentioned a leak in the Opportunity's radiator.

.... .. .... ..

• 1 Opportunity
• P Pancam
• 155450047 Number of seconds since Jan 1, 2004 at 11:58::55.816. (works out to Sol 307)
• Data product full frame EDR

And no, I've not heard any comments on this picture yet. There are other pictures with frost, but water would be puzzling on the Martian surface at that pressure and temperature.

I'm pretty sure they'd have mentioned a leak in the Opportunity's radiator.

.... .. .... ..

Here's the photo. Look to the wheel on your left hand side. I wonder if they were anticipating this happening.

Not at all.

The rovers are astonishing in what they can do, but a human would dramatically outpace them. What it might take a rover an entire day to do, a human could do in a 30-45 seconds.

Sol 337 was in fact leet, as was this entire mission, dewds.

A "Sol" is one Martian day, btw.

Map

I wonder if these rovers use Energiser (TM) solar panels... they just keep going and going and going :-)

Correction - Neptune was farther from Pluto from January 21, 1979 to Feb. 11, 1999 [nasa.gov] but at this time Pluto is farther from the sun than Neptune.

Of course, there's debate as to whether Pluto-Charon is a planet with a moon, or a double planet...

- Thomas;

cr

Troll? Bah. It was supposed to be a joke mocking the fact that the "Impact Probability" link is not directly tied to the asteriod's actual probability, but is instead a trivial script that simply displays whatever number you give in the URL. Look! The asteroid has a 99% impact probability! Oops, now it's 2%. Oh crap! Now it's 200%! How is that possible? -50%? What?

Oh, never mind.

Troll? Bah. It was supposed to be a joke mocking the fact that the "Impact Probability" link is not directly tied to the asteriod's actual probability, but is instead a trivial script that simply displays whatever number you give in the URL. Look! The asteroid has a 99% impact probability! Oops, now it's 2%. Oh crap! Now it's 200%! How is that possible? -50%? What?

Oh, never mind.

Troll? Bah. It was supposed to be a joke mocking the fact that the "Impact Probability" link is not directly tied to the asteriod's actual probability, but is instead a trivial script that simply displays whatever number you give in the URL. Look! The asteroid has a 99% impact probability! Oops, now it's 2%. Oh crap! Now it's 200%! How is that possible? -50%? What?

Oh, never mind.

Troll? Bah. It was supposed to be a joke mocking the fact that the "Impact Probability" link is not directly tied to the asteriod's actual probability, but is instead a trivial script that simply displays whatever number you give in the URL. Look! The asteroid has a 99% impact probability! Oops, now it's 2%. Oh crap! Now it's 200%! How is that possible? -50%? What?

Oh, never mind.

Does anyone else find it odd that each post mentions the year 2029 when in fact the year in question is actually 2044? From the NASA table YYYY-MM-DD.DD = 2044-04-13.29 where the .29 is a decimal fraction of the thirteenth day of April, 2044. The first pass-by included in the chart won't happen until 2030-04-13.88! Link to the chart.

try http://neo.jpl.nasa.gov/cgi-bin/ip?yes or http://neo.jpl.nasa.gov/cgi-bin/ip?-2

try http://neo.jpl.nasa.gov/cgi-bin/ip?yes or http://neo.jpl.nasa.gov/cgi-bin/ip?-2

NEOP of JPL

Two later than 2029 Torino class 2 possibilities remain, even though the news release mentions "no concern".

2004 MN4 upgraded again , now to Torino 1, years of danger 2030-2103
nasa risk page And there is two other of Torino 1, but not in my lifetime:
2004 VD17 impact 2062-2104
1997 XR2 impact 2101

There's still about a 1/268 chance that at least one object will hit Earth in next 100 years

Also, NASA gives my wang a 99% impact probability. Ladies, I'm talking to you.

This is Randy Pinkwood, signing off.

It turns out that probability page takes practically any number as a GET variable, so if you want, you can send a URL to your friends saying there's a 99% chance of impact:

http://neo.jpl.nasa.gov/cgi-bin/ip?9.9e-01

(They might fix it, so who knows how long the above URL will work...)

1 in 24,000 chance ATM

http://neo.jpl.nasa.gov/risk/2004mn4.html

earlier today the odds were about even

Impact Probability: 0.5

50.000000000% chance of Earth impact

or

1 in 2.0 chance

or

50.00000000% chance the asteroid will miss the Earth

Holy crap! There's a 100% probability of impact! Run for the hills!

http://neo.jpl.nasa.gov/cgi-bin/ip?1.8e-1

I don't know if there is enough tin foil to save us all....

The reason the probability of impact jumps around so much is as follows. The probability figure you have been seeing on the headlines is a CUMULATIVE probability of several potential impacts. In other words, they add the probability of the asteroid hitting Earth on this day, on that day, etc. for each close encounter. There were about 8 close encounters for which their probabilities were being summed to calculate this figure. There was a 1 in 38 chance for the asteroid hitting Earth on April 13, 2029, and this figure dominated the cumulative impact probability (1 in 37). Once more observations ruled out any impact on that day, the cumulative impact probability went to nearly zero. The remaining figure as of this posting, around 1.8e-05 (1 in 56,000), represents the probability of impact on the other close encounter dates (2037, 2044, etc.) as listed in the table. You will also note that the April 13, 2029 encounter has been REMOVED from this table. This is because there will be no impact; the table only lists remaining potential impacts.

See the pictures on the official Nasa sites.

Probability: 1.8%...

No, seriously: I just like the impact probability page at http://neo.jpl.nasa.gov/cgi-bin/ip?; put an arbitrary number and link it as an official and validated probability to your /. posts.

So how exactly did we go from a 1 in 37 chance to a 1 in 56000 chance in a few hours? My guess is that slashdot submitters was posting meaningless statistics and editors were letting them through in order to sensationalize the issue.

Too bad you'd be guessing wrong. NASA's information page on 2004 MN4 has been continuously updated throughout the weekend. Just a few hours ago, based on certain observations, it was concluded that the probability was 1/37. After further calculations and observations, the trajectory of the asteroid was plotted with enough confidence to warrant a reevaluation of the impact probabilities. Hence, we now see a 1/56,000 chance. It's all right there on NASA's page. Nothing sensationalistic about it.

How'd we get arrive at those probabilities within a matter of hours? Read the article summary. It does a good job of explaining it.

According to the impact risk site, the probability has been adjusted way down to 1.8e-05 with a Torino scale value of zero. A shame - I was hoping for some real drama and intrigue.

It's been updated to a 0 on the Torino Scale and according to the 2004 NM risk stats it has a 0.001800000% of hitting earth.

It's been updated to a 0 on the Torino Scale and according to the 2004 NM risk stats it has a 0.001800000% of hitting earth.

Anyway, it's only around 1.5 Gigaton potential yield....

And, in fact, hitting the page now (15:30 Pacific time), it's clear that the risk is gone; the object is now a Torino 0 (for all projected future encounters).

Sorry to break up the wise-cracking fun but the latest update at the impact risk page now has the asteroid at 0 on the Torino scale and the impact odds at 1 in 56,000.

They recently revised the page at http://neo.jpl.nasa.gov/risk/2004mn4.html to say the probability of impact is 1.8e-05, which is 1 in 55,555.

JPL's 2004MN4 page has been updated, and now there's no prediction for a near pass at all in 2029, and the cumulative impact odds are now 1 in 56,000.

Looks like they found a much older observation of the asteroid that allowed the orbit to be determined very precisely.

Looks like the odds have changed again. Down to 1 in 56,000 - It's even a zero on the torino scale now. Check it out here.

This asteroid has an orbit that takes him close to Earth from time to time.

This page from nasa lists the close calls from 2029 on (apparently before 2029 the asteroid is passing far enough that it's not a threat).

Guestimating volume if it's a sphere is (4 / 3) * pi * (((0.390/2) km)^3) = 31 059 355.8 m^3 (calc)

Guestimating density if it's a sphere is (7.9e+10 kg) / ((4 / 3) * pi * (((0.390/2) km)^3)) ~= 2540 kg / m^3 (calc), which is necessary for the calculator, and looks like a reasonable figure.

Totally guessing impact angle of 45 degrees.

I'm sure they actually have a decent fix on what part of the Earth it would hit. And a pretty decent guess of the angle of impact, too.

The low impact velocity means no fireball, apparently, and very little immediate effect once you get a few hundred miles away. It looks like this calculator doesn't mention the potential for tidal waves, though. Dunno what about that. And dunno if it's ignoring potential climate effects.

How about a tinfoil hat for one side of the asteroid?

Unfortunately, the Yarkovsky Effect - deflecting an asteroid by differentially heating parts of its surface - is likely to be too small to save us. Deflection of a rock comparable in size to 2004MN4, namely 6489 Golevka, was observed as 15km in 12 years of observation. Depending on the eventual impact point (if any) of 2004MN4, we may have to deflect it by thousands of kilometers.

Yes, you'll probably get much more deflection by wrapping half the rock in mylar (and/or dusting the other half of it with soot), rather than relying on the natural effect observed on 6489 Golevka, but we don't know enough about 2004MN4 (albedo/mass) to guess yet.

It gets even worse

Here is a movie I just made (3ivx 4.5, 528KB) of the possible orbital dance that Earth and 2004 MN4 may have in April - May 2029.

I made this video using the 2004 MN4 orbital data from the NASA NEO site. The program I used, Starry Night, doesn't take into account things such as gravitational attraction, but it's a reasonable view showing just how close we'll be to 2004 MN4 when it comes around in 2029

Or, if you prefer, they are now at 1 in 1,000,000.

This edition of Fun With URLs has been brought to you courtesy of an overly trusting NASA webmaster.

Or, if you prefer, they are now at 1 in 1,000,000.

This edition of Fun With URLs has been brought to you courtesy of an overly trusting NASA webmaster.

Talking of the Torino scale, does anyone have any idea at what percentage probablility of impact it would move up to the orange (threatening) section of the scale? As far as I can tell, both the orange and red (impact!) sections are based more on the predicted amount of damage rather than likelihood of a collision, so I'm guessing it's pretty high. Also, assuming that the estimated size and consistency of the object don't change, it looks like an object would not be given two separate orange or red scores. If that's the case then I'm guessing that if MN4 is going to hit us it'll go to five, then eight based on a play with the damage predictor.

The Torino scale [ref1] is based on kinetic energy in megatons vs. probability of impact. A 4 or 5 is only for objects with energy in the 100 MT to 100,000 MT class and a probability in the 1% to ~99% range. Currently, 2004 MN4 is estimated [ref2] to have an impact energy of about 1,500 MT with a probability of 2.7% To rank a 5 (at the same energy) I calculate that the asteroid would need about a 16% impact probability. It would then stay at 5 for up to 99%

There can only be one Torino integer/color per close earth approach. It could only jump from a 5 to a 9 if the probability exceeds 99% But an 8 (or a 3) are unlikely unless the size estimate is way too high. This asteroid will most likely hover at 4 for some time while new observations are collected. Later, it could drop from 4 to 2 or (less likely) jump from 4 to 9.

[1]Torino Scale from Asteroid and Comet Impact Hazards
[2]2004 MN4 Impact Risk (based on 176 observations collected through Dec. 27.084)

Talking of the Torino scale, does anyone have any idea at what percentage probablility of impact it would move up to the orange (threatening) section of the scale? As far as I can tell, both the orange and red (impact!) sections are based more on the predicted amount of damage rather than likelihood of a collision, so I'm guessing it's pretty high. Also, assuming that the estimated size and consistency of the object don't change, it looks like an object would not be given two separate orange or red scores. If that's the case then I'm guessing that if MN4 is going to hit us it'll go to five, then eight based on a play with the damage predictor.

The Torino scale [ref1] is based on kinetic energy in megatons vs. probability of impact. A 4 or 5 is only for objects with energy in the 100 MT to 100,000 MT class and a probability in the 1% to ~99% range. Currently, 2004 MN4 is estimated [ref2] to have an impact energy of about 1,500 MT with a probability of 2.7% To rank a 5 (at the same energy) I calculate that the asteroid would need about a 16% impact probability. It would then stay at 5 for up to 99%

There can only be one Torino integer/color per close earth approach. It could only jump from a 5 to a 9 if the probability exceeds 99% But an 8 (or a 3) are unlikely unless the size estimate is way too high. This asteroid will most likely hover at 4 for some time while new observations are collected. Later, it could drop from 4 to 2 or (less likely) jump from 4 to 9.

[1]Torino Scale from Asteroid and Comet Impact Hazards
[2]2004 MN4 Impact Risk (based on 176 observations collected through Dec. 27.084)

Essentially this is a device to 'tune' to any of the millions of frequencies that are in the upper part of the non-visible Electromagnetic spectrum. TV and Radio are broadcast in the long wavelength low frequency part of the specturm. Pretty pictures at Nasa

Anyway, Here's a Salon Article about the polictical & technical aspects of it:
http://www.salon.com/tech/feature/2003/03/12/spect rum/index.html (Warning: you may have to click through a stupid ad.)

Or, if you prefer, they are now at 1 in 1,000,000.

Has anyone else looked closely at the 1/45 URL?

Or, if you prefer, they are now at 1 in 1,000,000.

Has anyone else looked closely at the 1/45 URL?

Definition of flight, according to NASA:

The movement of an object through the atmosphere or through space, sustained by aerodynamic, aerostatic, or reaction forces, or by orbital speed; especially, the movement of a man-operated or man-controlled device, such as a rocket, a space probe, a space vehicle, or aircraft

So, yes, you can consider it all human flight. All of these devices result in aerodynamically produced lift, and allow for man-controlled movement through the atmosphere.