Slashdot Mirror

Actually, the Challenger mission was actually mission "51-L". STS-51 came 7 years later, and involved a four-times-aborted launch of the Discovery.

having read The Palermo Technical Impact Hazard Scale I'm thinking that loosely coupled Llama trains are less a hazard to us void engineers here in Houston than this asteroid is. Just think of the hazards of trying to explain logarithmic scales to the masses. I can feel blood pressure spiking at JSC already.

Still, like the doc's say:
Potential impacts with positive Palermo Scale values will generally indicate situations that merit some level of concern.

so 0.06 merits some concern, but doesn't justify drama llamas

considering a very resembling STS-51 less successful one.

Agreed. I read the headline, skimmed the text and thought, "why the hell is there a news item about an AGP slot being added to a space shuttle?"

Only after checking the article did it become clear...

considering a very resembling STS-51 less successful one.

" This would require two things:

a) The period of the asteroid and the earth must be synchronized to a ratio of 3/7 to within less than app. 1 hour in 60 years - an accuracy of approximately 1:500000"

You are asking a good question. The reason why the close approaches occur on the same day of the year is because 2002-NT7's orbit is closest to Earth's orbit at one point. That point does shift around. The current model suggests the closest approach occurs at:

1. Feb 1, 2019 12h UTC
2. Feb 1, 2044 16h UTC (25 years, 4h later)
3. Feb 1, 2053 0h UTC (9 years, -16h later)
4. Feb 1, 2060 17h UTC (7 years, 17h later)
5. Feb 1, 2078 5h UTC (18 years, -12h later)
6. ... others with skips of 7 to 14 years +/- a few hours later

The path of 2002-NT7 will next cross earth's orbit plane going upward at a point about 132.1708757 degrees from the Fall Equinox. Now 132.1708757 degrees / 360 degrees = 0.3671413214 of a circle. Using 365.2564 days (Earth's year), 0.3671413214 of a circle * 365.2564 days = about 134.1 days from the Fall Equinox. 134.1 days from Sep 23 (~06 hr UTC) lands one near 1 Feb.

Take a look at this 2002-NT7 orbit diagram. The dark blue part of 2002-NT7's orbit is below Earth's plane. The light blue part is above Earth's plane. The yellow line from the Sun (red dot in center) going down and to the right is the 0 degree fall equinox line. The vertical yellow line, 132.1708757 degrees from the equinox line (as measured in the plane of Earth's orbit, not the plane shown on your screen) shows where 2002-NT7 crosses Earth's orbit plane. That crossing spot (the place where the dark/light parts of 2002-NT7's orbit meet near the yellow line), you will notice, is very close to Earth's orbit. That spot is the place where Earth is found on/near Feb 1. No other place on Earth's or 2002-NT7's orbit comes as close.

You ask another good question about deflection:

" b) All those near flybys must not significantly alter the course of the asteroid. (comparison: geostationary satellite orbit is app. 35000km, and the satellite is deflected by 360 degrees in one day)"

Not every object that gets within 35000km of Earth enters a geostationary orbit. The reason why 2002-NT7 is not captured by earth is that it is moving about 26.25 km/second as it crosses Earth's orbit plane. It is moving too fast to be captured by Earth and pulled into a orbit around our planet.

FYI: An object orbiting the Earth once a day 35,000 km above the surface is moving about 3 km/second with respect to the center of the Earth. The 26.25 km/second speed of 2002-NT7 is much faster.

BTW: Earth DOES deflect 2002-NT7. The crossing point and angle in inclination do shift a but after a close approach, but not by a huge amount. These close passes make the 2002-NT7 orbit tricky to model.

On a different question that somebody else asked:

" Why doesn't the XYZZY solar system program show these close approaches?"

Your typical astro/solar system display program that runs on your PC (XEphem, RedShift, TheSky, or even that Java app on the JPL site) uses simplified assumptions that are OK for general approximation of objects that do not have significant encounters. They frequently use point size masses and only take into account the Grav pull of the Sun and major planets. High precision models must use much much much more complex models. For example, in addition to accurate 2002-NT7 observations (to measure its position) one must use a non-point Earth model. That gravity lump called EurAsia has a slightly different "tug" than the Pacific Ocean, for example. Normally that difference is not critical, but when one is trying to predict with high precision year in the future, such details can become important.

Permit me to end with a note about critical NASA mission called GRACE.

There is a very critical mission (largely ignored by the general press) known called GRACE. GRACE stands for Gravity Recovery and Climate Experiment. The mission will obtain obtain accurate global and high-resolution determination of both the static and the time-variable components of the Earth's gravity field. This goal will be achieved by making accurate measurements of the inter-satellite range change to within one micron between two co-planar, low altitude polar orbiting satellites, using a microwave tracking system.

GRACE will provide us with an accurate Gravity map which will improve the modeling of very close approaches. I am looking forward to the day with GRACE's gravity maps can be used to establish more detailed close approach orbit models. I wish the GRACE team all the best!

IAACM (I Am A Celestial Mechanic) :-) and I hope this helps.

" This would require two things:

a) The period of the asteroid and the earth must be synchronized to a ratio of 3/7 to within less than app. 1 hour in 60 years - an accuracy of approximately 1:500000"

You are asking a good question. The reason why the close approaches occur on the same day of the year is because 2002-NT7's orbit is closest to Earth's orbit at one point. That point does shift around. The current model suggests the closest approach occurs at:

1. Feb 1, 2019 12h UTC
2. Feb 1, 2044 16h UTC (25 years, 4h later)
3. Feb 1, 2053 0h UTC (9 years, -16h later)
4. Feb 1, 2060 17h UTC (7 years, 17h later)
5. Feb 1, 2078 5h UTC (18 years, -12h later)
6. ... others with skips of 7 to 14 years +/- a few hours later

The path of 2002-NT7 will next cross earth's orbit plane going upward at a point about 132.1708757 degrees from the Fall Equinox. Now 132.1708757 degrees / 360 degrees = 0.3671413214 of a circle. Using 365.2564 days (Earth's year), 0.3671413214 of a circle * 365.2564 days = about 134.1 days from the Fall Equinox. 134.1 days from Sep 23 (~06 hr UTC) lands one near 1 Feb.

Take a look at this 2002-NT7 orbit diagram. The dark blue part of 2002-NT7's orbit is below Earth's plane. The light blue part is above Earth's plane. The yellow line from the Sun (red dot in center) going down and to the right is the 0 degree fall equinox line. The vertical yellow line, 132.1708757 degrees from the equinox line (as measured in the plane of Earth's orbit, not the plane shown on your screen) shows where 2002-NT7 crosses Earth's orbit plane. That crossing spot (the place where the dark/light parts of 2002-NT7's orbit meet near the yellow line), you will notice, is very close to Earth's orbit. That spot is the place where Earth is found on/near Feb 1. No other place on Earth's or 2002-NT7's orbit comes as close.

You ask another good question about deflection:

" b) All those near flybys must not significantly alter the course of the asteroid. (comparison: geostationary satellite orbit is app. 35000km, and the satellite is deflected by 360 degrees in one day)"

Not every object that gets within 35000km of Earth enters a geostationary orbit. The reason why 2002-NT7 is not captured by earth is that it is moving about 26.25 km/second as it crosses Earth's orbit plane. It is moving too fast to be captured by Earth and pulled into a orbit around our planet.

FYI: An object orbiting the Earth once a day 35,000 km above the surface is moving about 3 km/second with respect to the center of the Earth. The 26.25 km/second speed of 2002-NT7 is much faster.

BTW: Earth DOES deflect 2002-NT7. The crossing point and angle in inclination do shift a but after a close approach, but not by a huge amount. These close passes make the 2002-NT7 orbit tricky to model.

On a different question that somebody else asked:

" Why doesn't the XYZZY solar system program show these close approaches?"

Your typical astro/solar system display program that runs on your PC (XEphem, RedShift, TheSky, or even that Java app on the JPL site) uses simplified assumptions that are OK for general approximation of objects that do not have significant encounters. They frequently use point size masses and only take into account the Grav pull of the Sun and major planets. High precision models must use much much much more complex models. For example, in addition to accurate 2002-NT7 observations (to measure its position) one must use a non-point Earth model. That gravity lump called EurAsia has a slightly different "tug" than the Pacific Ocean, for example. Normally that difference is not critical, but when one is trying to predict with high precision year in the future, such details can become important.

Permit me to end with a note about critical NASA mission called GRACE.

There is a very critical mission (largely ignored by the general press) known called GRACE. GRACE stands for Gravity Recovery and Climate Experiment. The mission will obtain obtain accurate global and high-resolution determination of both the static and the time-variable components of the Earth's gravity field. This goal will be achieved by making accurate measurements of the inter-satellite range change to within one micron between two co-planar, low altitude polar orbiting satellites, using a microwave tracking system.

GRACE will provide us with an accurate Gravity map which will improve the modeling of very close approaches. I am looking forward to the day with GRACE's gravity maps can be used to establish more detailed close approach orbit models. I wish the GRACE team all the best!

IAACM (I Am A Celestial Mechanic) :-) and I hope this helps.

Not so good news: The odds of an impact prior to 2060 was 1 in ~6,600,000 and now is about 1 in ~4,500,000.

The Feb 1, 2060 approach is now very close, only 3570 km! There is still a great deal of uncertainly. At 1 sigma, the margin of error is about +/- 29600 km.

Sure, the center line of the model comes very close to the earth. And sure, the 1 sigma margin of error of the model paints a wide path that intersects the Earth. However the model relevance (i.e., how well does the orbit model match the real 2002-NT7 asteroid) is still in doubt and needs more observational data to refine it.

To give you an example of how small effects can change the model: A 125 second model error, adjusted in the wrong way, out at Feb 1, 2060 (about 1 part in about 14,600,000) is all that it takes to turn a miss into an impact.

At the risk of stating the obvious: Just because the orbit model draws a line thru your neighborhood doesn't mean that the Asteroid will follow the same path. We have to improve the model and validate it with direct and accurate observations over time before we can begin to place more trust in the model reflecting reality. So continue to pay your bills and refrain from end the world rioting. :-)

For those who are keeping track. The following is the list of close approaches (according to the model):

1. Feb 1, 2019 (distance: ~28500 km)
2. Feb 1, 2044 (distance: ~91100 km)
3. Feb 1, 2053 (distance: ~53500 km)
4. Feb 1, 2060 (distance: ~3570 km)
5. Feb 1, 2078 (distance: ~15900 km)
6. with interesting passes every 7 to 14 years after that
   (your asteroid's mileage may vary :-))

The Palermo Scale value has changed from -0.05 to -0.25. (A lower number means less risk) However the Torino Scale remains at 1. (A value >0 means there is something to worry about). The main reason for the Palermo scale drop is that there are fewer close approaches to worry about over the next 50 to 100 years. Fewer close approaches means fewer risky events. Fewer risky events in the next 50 to 100 years results in a lower Palermo value.

IMHO, It is still the case that there is next to nil chance of impact before 2060. It is 2060 and beyond events that are of concern. It is the pattern of orbit adjustments at and beyond 2060 that may be of concern.

p.s. My memory of the other asteroid that as a non-zero Torino value was bad. The other non-zero Torino risk object is the asteroid 1997-XR2 with a -2.44 Palermo Scale value and the impact odds of 1 in about 970,000. While better odds than 2002-NT7, it is smaller ... only 230 meters across. The impact energy of 2002-NT7 (if it were to hit) is some 3333 times as great as 1997-XR2. And while an impact of 1997-XR2 (somewhere around June 1, 2101) would not be fun, it is does not have nearly the same potential impact as 2002-NT7.

The other object on the hit parade that is being watched is 2002-NY40. However we only have 76 observations over 9+ days so things are still WAY WAY too early to tell or say anything. It has a -1.91 Palermo value and a 0 Torino value so far.

IMHO, I would not be surprised to see the 2002-NY40 drop in the charts as the days go by.

Well I have other work that I need to do, so it may be a day or so before I update things again ... unless something changes dramatically ...

Not so good news: The odds of an impact prior to 2060 was 1 in ~6,600,000 and now is about 1 in ~4,500,000.

The Feb 1, 2060 approach is now very close, only 3570 km! There is still a great deal of uncertainly. At 1 sigma, the margin of error is about +/- 29600 km.

Sure, the center line of the model comes very close to the earth. And sure, the 1 sigma margin of error of the model paints a wide path that intersects the Earth. However the model relevance (i.e., how well does the orbit model match the real 2002-NT7 asteroid) is still in doubt and needs more observational data to refine it.

To give you an example of how small effects can change the model: A 125 second model error, adjusted in the wrong way, out at Feb 1, 2060 (about 1 part in about 14,600,000) is all that it takes to turn a miss into an impact.

At the risk of stating the obvious: Just because the orbit model draws a line thru your neighborhood doesn't mean that the Asteroid will follow the same path. We have to improve the model and validate it with direct and accurate observations over time before we can begin to place more trust in the model reflecting reality. So continue to pay your bills and refrain from end the world rioting. :-)

For those who are keeping track. The following is the list of close approaches (according to the model):

1. Feb 1, 2019 (distance: ~28500 km)
2. Feb 1, 2044 (distance: ~91100 km)
3. Feb 1, 2053 (distance: ~53500 km)
4. Feb 1, 2060 (distance: ~3570 km)
5. Feb 1, 2078 (distance: ~15900 km)
6. with interesting passes every 7 to 14 years after that
   (your asteroid's mileage may vary :-))

The Palermo Scale value has changed from -0.05 to -0.25. (A lower number means less risk) However the Torino Scale remains at 1. (A value >0 means there is something to worry about). The main reason for the Palermo scale drop is that there are fewer close approaches to worry about over the next 50 to 100 years. Fewer close approaches means fewer risky events. Fewer risky events in the next 50 to 100 years results in a lower Palermo value.

IMHO, It is still the case that there is next to nil chance of impact before 2060. It is 2060 and beyond events that are of concern. It is the pattern of orbit adjustments at and beyond 2060 that may be of concern.

p.s. My memory of the other asteroid that as a non-zero Torino value was bad. The other non-zero Torino risk object is the asteroid 1997-XR2 with a -2.44 Palermo Scale value and the impact odds of 1 in about 970,000. While better odds than 2002-NT7, it is smaller ... only 230 meters across. The impact energy of 2002-NT7 (if it were to hit) is some 3333 times as great as 1997-XR2. And while an impact of 1997-XR2 (somewhere around June 1, 2101) would not be fun, it is does not have nearly the same potential impact as 2002-NT7.

The other object on the hit parade that is being watched is 2002-NY40. However we only have 76 observations over 9+ days so things are still WAY WAY too early to tell or say anything. It has a -1.91 Palermo value and a 0 Torino value so far.

IMHO, I would not be surprised to see the 2002-NY40 drop in the charts as the days go by.

Well I have other work that I need to do, so it may be a day or so before I update things again ... unless something changes dramatically ...

Not so good news: The odds of an impact prior to 2060 was 1 in ~6,600,000 and now is about 1 in ~4,500,000.

The Feb 1, 2060 approach is now very close, only 3570 km! There is still a great deal of uncertainly. At 1 sigma, the margin of error is about +/- 29600 km.

Sure, the center line of the model comes very close to the earth. And sure, the 1 sigma margin of error of the model paints a wide path that intersects the Earth. However the model relevance (i.e., how well does the orbit model match the real 2002-NT7 asteroid) is still in doubt and needs more observational data to refine it.

To give you an example of how small effects can change the model: A 125 second model error, adjusted in the wrong way, out at Feb 1, 2060 (about 1 part in about 14,600,000) is all that it takes to turn a miss into an impact.

At the risk of stating the obvious: Just because the orbit model draws a line thru your neighborhood doesn't mean that the Asteroid will follow the same path. We have to improve the model and validate it with direct and accurate observations over time before we can begin to place more trust in the model reflecting reality. So continue to pay your bills and refrain from end the world rioting. :-)

For those who are keeping track. The following is the list of close approaches (according to the model):

1. Feb 1, 2019 (distance: ~28500 km)
2. Feb 1, 2044 (distance: ~91100 km)
3. Feb 1, 2053 (distance: ~53500 km)
4. Feb 1, 2060 (distance: ~3570 km)
5. Feb 1, 2078 (distance: ~15900 km)
6. with interesting passes every 7 to 14 years after that
   (your asteroid's mileage may vary :-))

The Palermo Scale value has changed from -0.05 to -0.25. (A lower number means less risk) However the Torino Scale remains at 1. (A value >0 means there is something to worry about). The main reason for the Palermo scale drop is that there are fewer close approaches to worry about over the next 50 to 100 years. Fewer close approaches means fewer risky events. Fewer risky events in the next 50 to 100 years results in a lower Palermo value.

IMHO, It is still the case that there is next to nil chance of impact before 2060. It is 2060 and beyond events that are of concern. It is the pattern of orbit adjustments at and beyond 2060 that may be of concern.

p.s. My memory of the other asteroid that as a non-zero Torino value was bad. The other non-zero Torino risk object is the asteroid 1997-XR2 with a -2.44 Palermo Scale value and the impact odds of 1 in about 970,000. While better odds than 2002-NT7, it is smaller ... only 230 meters across. The impact energy of 2002-NT7 (if it were to hit) is some 3333 times as great as 1997-XR2. And while an impact of 1997-XR2 (somewhere around June 1, 2101) would not be fun, it is does not have nearly the same potential impact as 2002-NT7.

The other object on the hit parade that is being watched is 2002-NY40. However we only have 76 observations over 9+ days so things are still WAY WAY too early to tell or say anything. It has a -1.91 Palermo value and a 0 Torino value so far.

IMHO, I would not be surprised to see the 2002-NY40 drop in the charts as the days go by.

Well I have other work that I need to do, so it may be a day or so before I update things again ... unless something changes dramatically ...

Not so good news: The odds of an impact prior to 2060 was 1 in ~6,600,000 and now is about 1 in ~4,500,000.

The Feb 1, 2060 approach is now very close, only 3570 km! There is still a great deal of uncertainly. At 1 sigma, the margin of error is about +/- 29600 km.

Sure, the center line of the model comes very close to the earth. And sure, the 1 sigma margin of error of the model paints a wide path that intersects the Earth. However the model relevance (i.e., how well does the orbit model match the real 2002-NT7 asteroid) is still in doubt and needs more observational data to refine it.

To give you an example of how small effects can change the model: A 125 second model error, adjusted in the wrong way, out at Feb 1, 2060 (about 1 part in about 14,600,000) is all that it takes to turn a miss into an impact.

At the risk of stating the obvious: Just because the orbit model draws a line thru your neighborhood doesn't mean that the Asteroid will follow the same path. We have to improve the model and validate it with direct and accurate observations over time before we can begin to place more trust in the model reflecting reality. So continue to pay your bills and refrain from end the world rioting. :-)

For those who are keeping track. The following is the list of close approaches (according to the model):

1. Feb 1, 2019 (distance: ~28500 km)
2. Feb 1, 2044 (distance: ~91100 km)
3. Feb 1, 2053 (distance: ~53500 km)
4. Feb 1, 2060 (distance: ~3570 km)
5. Feb 1, 2078 (distance: ~15900 km)
6. with interesting passes every 7 to 14 years after that
   (your asteroid's mileage may vary :-))

The Palermo Scale value has changed from -0.05 to -0.25. (A lower number means less risk) However the Torino Scale remains at 1. (A value >0 means there is something to worry about). The main reason for the Palermo scale drop is that there are fewer close approaches to worry about over the next 50 to 100 years. Fewer close approaches means fewer risky events. Fewer risky events in the next 50 to 100 years results in a lower Palermo value.

IMHO, It is still the case that there is next to nil chance of impact before 2060. It is 2060 and beyond events that are of concern. It is the pattern of orbit adjustments at and beyond 2060 that may be of concern.

p.s. My memory of the other asteroid that as a non-zero Torino value was bad. The other non-zero Torino risk object is the asteroid 1997-XR2 with a -2.44 Palermo Scale value and the impact odds of 1 in about 970,000. While better odds than 2002-NT7, it is smaller ... only 230 meters across. The impact energy of 2002-NT7 (if it were to hit) is some 3333 times as great as 1997-XR2. And while an impact of 1997-XR2 (somewhere around June 1, 2101) would not be fun, it is does not have nearly the same potential impact as 2002-NT7.

The other object on the hit parade that is being watched is 2002-NY40. However we only have 76 observations over 9+ days so things are still WAY WAY too early to tell or say anything. It has a -1.91 Palermo value and a 0 Torino value so far.

IMHO, I would not be surprised to see the 2002-NY40 drop in the charts as the days go by.

Well I have other work that I need to do, so it may be a day or so before I update things again ... unless something changes dramatically ...

Then again, a number this close to 0 means that the chances of such an impact over the next 20 years has just about doubled with this observation...

Nasa's explanation of the palermo scale

Well, according to the page refered to the analysis is:
"based on 102 observations spanning 13.570 days (2002-Jul-09.3768 to 2002-Jul-22.94706)"

Well, I would say that's pretty up-to-date.

Oops

Actually, I did some work for BBC Online, back in the day, and this picture is basically a stock-image that they have. It is sourced from NASA's Image Exchange and since NASA images are royalty-free, this particular pic has been around the block a few times.

I guess the fact that there are, unsurprisingly, no photographs of such events occurring means that journos with a deadline and a desperate need to source an image resort to this old cliche. It's the equivalent of slapping a cheesy space-shuttle launch onto any story about space technology. Easy and cheap and more often than not irrelevant to the story in hand.

http://neo.jpl.nasa.gov/risk/doc/palermo.html
Is it that difficult to make an anchor link? Or is HTML too hard for you?

" Such an impact would be on par (but somewhat less) with the impact that ended the Dinosaurs 65 million years ago."

The KT event asteroid that hit 65 million years and formed the Chicxulub crater ago was almost certainly larger. Estimates of that impactor have ranged from 4km to 18km in diameter with more recent evidence suggesting that the smaller size estimates may be more accurate. Others prefer the larger sizes. Even if they are correct and the KT-impactor was on the larger end of the scale, an impact of a 2km asteroid is no trivial matter.

Assuming the same density, the ~2km 2002-NT7 has about 1/8th the mass of KT impactor. Perhaps 1/10th the mass if 2002-NT7 turns out to be a lower than average density asteroid.

When I said:

" It is not known where on earth it might impact. Too early to tell. Not that is matters for a rock of this size ... anyway on early will suffer sooner or slightly later."

I should have said:

" It is not known where on earth it might impact. Too early to tell. Not that is matters where a rock of this size hits. No matter where it hits, civilization will suffer sooner (i.e., near the impact) or later (i.e., somewhere else on the earth)."

I want to repeat that the chance of impact prior to 2060, based on the current limited set of observations, is slim (1 in ~100,000 more).

The chance of an 2002-NT7 impact after 2060 is uncertain. It is hard to estimate the location of 2002-NT7 on/after 2060 in part because of the 4 prior close approaches and in part because positions become more uncertain as time goes on.

It is common to consider asteroid positions 100 years or more in the future to uncertain enough as to not be useful to estimate impact risk. This 100 year uncertainty limit gets shorter when one throws in 1 or more close approaches.

While 2002-NT7's orbit position will become better defined with additional data, the risk assessment of the 2060 pass (and beyond) will remain more uncertain for some time. Time (and more accurate observations) will tell how much the next generations will have to worry or not about 2002-NT7.

IMHO, there is nil chance of an impact by 2002-NT7 before 2060. The trend / perturbations on 2002-NT7 suggest that things could get ugly later on. Monitoring of 2002-NT7 over time, plus improved orbit models will tell how much future generations will need to worry about an impact >= 2060.

NASA's NEO program currently states that NT7 has a .00001 chance of striking Earth at all, and a .000052 chance of specifically hitting us in 2017. Of course, the calculations will be refined as time passes, but from my first looks at the slim probabilities, it doesn't seem like it will be much of a problem. The only difference seems to be that it is slightly more likely to hit than previously discovered NEOs.

According to this it looks like
2002 NY40 will be closer on Aug 17th of this year
than NT comes in 2019. Check for yourself.

I looked at the simulation at NASA and as far as I am concerned, Earth already crashed with this rock at 1st February 1980. It was about 20 times closer to Earth than it is supposed to be in 2019.

Maybe it's just that that page hasn't been updated. As long as the probability of impact remains fairly constant, the Palermo Scale will rise as the event gets closer. This is how it's calculated:

Palermo Scale = log [Probability of impact / (Yearly probability of impact * Years until event)]

More detail here.

A Palermo value of 0.06 means that the risk from this object is elevated above the background risk for such objects by about 15%. (The 0.06 is the log of the ratio of the risk to the background risk.) So however worried you were yesterday about collisions with 2 km asteroids, you can be 15% more worried today.

In short, not worth losing sleep over.

A Palermo value of 0.06 means that the risk from this object is elevated above the background risk for such objects by about 15%. (The 0.06 is the log of the ratio of the risk to the background risk.) So however worried you were yesterday about collisions with 2 km asteroids, you can be 15% more worried today.

In short, not worth losing sleep over.

Someone above posted a URL to the JPL's Orbits applet to simulate the orbit of NT7. Fast forwarding to 2019 and watching the animation shows NT7 coming "close", but not near as close as on July 1, 2075. Now THAT's close...

The higher-precision text-based orbital calculator is more accurate. (And overloaded right now.) It has 2002 NT7 in its database. Both claim January 28, 2019 is the date of closest approach. Both claim closest approach around 0.8 AU. Remember, this is projecting many orbits ahead, and small-object orbit projection is inherently noisy because minor disturbing forces matter.

Either we'll know it's a definite miss in a few weeks, or this will be a worry for some time to come.

The higher-precision text-based orbital calculator is more accurate. (And overloaded right now.) It has 2002 NT7 in its database. Both claim January 28, 2019 is the date of closest approach. Both claim closest approach around 0.8 AU. Remember, this is projecting many orbits ahead, and small-object orbit projection is inherently noisy because minor disturbing forces matter.

Either we'll know it's a definite miss in a few weeks, or this will be a worry for some time to come.

"...while Palermo Scale values between -2 and 0 indicate situations that merit careful monitoring. Potential impacts with positive Palermo Scale values will generally indicate situations that merit some level of concern."

"The scale compares the likelihood of the detected potential impact with the average risk posed by objects of the same size or larger over the years until the date of potential impact."

2002 NT7 Impact Risk

It doesn't look so bad. -0.14 on the Palermo Scale (recently downgraded?).

For those wondering what they're talking about, NASA has a site about it here

Check out the 3d view here.

Just fast-forward to Feb-1 2019, set the center on earth, and zoom in.

ARe we going to get pictures Pluto and Neptune back?

Um, Voyager 2 passed Neptune in 1989 and took some nice pictures.

None of them are headed anywhere near Pluto.

Frankly, all that i can do is offer my best jacques cousteau impression, and hope that they don't evolve further.

NASA

Another Squid Site

Discovery Channel and the Giant Squid

Weird Squids In Action (that one's just fun for the cool giant squid graphics- how would YOU have done it?)

A A 1996 article regarding giant squid discovery>

A 2002 discovery of a MUCH smaller 'giant' squid

and of course, proof that there's a convention group for everything.

And if anybody wants to know how i happen to know any of this, let's just say that i dated a marine biologist. It won't be true, but it would make my mum happy....

• Software Assurance Technology Center
• NASA's IV&V Facility
• NASA's Software Engineering Lab
• Practical Software & Systems Measurement

I particularly like the *FREE* ARM (Automated Requirements Measurement) tool from the SATC (first link). Granted it only runs on Windoze, but you can get it to parse a 300+ page req doc and count all the requirements, weak phrases, etc. for you. Handy tool.

• Software Assurance Technology Center
• NASA's IV&V Facility
• NASA's Software Engineering Lab
• Practical Software & Systems Measurement

I particularly like the *FREE* ARM (Automated Requirements Measurement) tool from the SATC (first link). Granted it only runs on Windoze, but you can get it to parse a 300+ page req doc and count all the requirements, weak phrases, etc. for you. Handy tool.

• Software Assurance Technology Center
• NASA's IV&V Facility
• NASA's Software Engineering Lab
• Practical Software & Systems Measurement

I particularly like the *FREE* ARM (Automated Requirements Measurement) tool from the SATC (first link). Granted it only runs on Windoze, but you can get it to parse a 300+ page req doc and count all the requirements, weak phrases, etc. for you. Handy tool.

My post needs to be slightly corrected: the cause of the power loss is mostly due to aging of the thermal couple, not the decay of the radioactivity.

More information from Pioneer home page:

Electrical power is provided by four radioisotope thermoelectric generators (RTG), each providing 40 watts of power at launch. Two three-rod trusses, 120 degrees apart, project from the equipment compartment to deploy the RTG power sources about 10 feet from the center of the spacecraft. A third boom, 120 degrees from the others, projects from the experiments compartment and positions the helium vector magnetometer sensor 20 feet from the spacecraft center.

and from the FAQ

Question:Why does the RTG power decrease?
Answer: Power for the Pioneer 10 is generated by the Radioisotope Thermoelectric Generators (RTG's). Heat from the decay of the plutonium 238 isotope is converted by thermoelectric couples into electrical current. The electrical output depends on the hot junction temperature, the thermal path to the radiator fins, and the cold junction temperature. It is the degradation of the thermoelectric junction that has the major effect in decreasing the power output of the RTG. In the 30-year time scale operation of Pioneer 10, the 92 year half-life of the isotope does not appreciably affect the RTG operation. The nuclear decay heat will keep the hot junction temperature hot for many years but unfortunately will not be able to be converted into enough electricity to power the transmitter for much longer.

As an aside, this type of power source is behind the plutonium scare-mongering that surrounded Cassini.

My post needs to be slightly corrected: the cause of the power loss is mostly due to aging of the thermal couple, not the decay of the radioactivity.

More information from Pioneer home page:

Electrical power is provided by four radioisotope thermoelectric generators (RTG), each providing 40 watts of power at launch. Two three-rod trusses, 120 degrees apart, project from the equipment compartment to deploy the RTG power sources about 10 feet from the center of the spacecraft. A third boom, 120 degrees from the others, projects from the experiments compartment and positions the helium vector magnetometer sensor 20 feet from the spacecraft center.

and from the FAQ

Question:Why does the RTG power decrease?
Answer: Power for the Pioneer 10 is generated by the Radioisotope Thermoelectric Generators (RTG's). Heat from the decay of the plutonium 238 isotope is converted by thermoelectric couples into electrical current. The electrical output depends on the hot junction temperature, the thermal path to the radiator fins, and the cold junction temperature. It is the degradation of the thermoelectric junction that has the major effect in decreasing the power output of the RTG. In the 30-year time scale operation of Pioneer 10, the 92 year half-life of the isotope does not appreciably affect the RTG operation. The nuclear decay heat will keep the hot junction temperature hot for many years but unfortunately will not be able to be converted into enough electricity to power the transmitter for much longer.

As an aside, this type of power source is behind the plutonium scare-mongering that surrounded Cassini.

Perhaps NASA does have a theory to explain the anomalies in the flight paths of Pioneer 10 & 11, but it's classified?

This is just the tip of the iceberg. But go ahead and believe what you want, hell - believe what the government scientists tell you. I won't.

Anyway, Voyager 1 appears to be just short of 8 billion miles from the sun rather than "well over 7" as mentioned below.

At 22:14 CST on July 6, 1989 they recorded a twin flash originating in a storm top cloud and discharging into the stratosphere.

Don't get me wrong, it'll be wonderful if the company can pull this off. It just looks like there are an awful lot of unanswered questions as to what it'll be like up at that elevation for extended periods. If I were starting up an isp based on the technology, I'd make it clear to my customers that there may be black out periods when I bring the planes down to avoid losing them to a major storm. The tradeoff is when the planes are up, they'll get terrific throughput. 98% uptime may be good enough for most people. For the 99.999 crowd, they could use the service to supplement whatever they're doing and fall back to slower circuits during a storm.

At 22:14 CST on July 6, 1989 they recorded a twin flash originating in a storm top cloud and discharging into the stratosphere.

Don't get me wrong, it'll be wonderful if the company can pull this off. It just looks like there are an awful lot of unanswered questions as to what it'll be like up at that elevation for extended periods. If I were starting up an isp based on the technology, I'd make it clear to my customers that there may be black out periods when I bring the planes down to avoid losing them to a major storm. The tradeoff is when the planes are up, they'll get terrific throughput. 98% uptime may be good enough for most people. For the 99.999 crowd, they could use the service to supplement whatever they're doing and fall back to slower circuits during a storm.

At 22:14 CST on July 6, 1989 they recorded a twin flash originating in a storm top cloud and discharging into the stratosphere.

Don't get me wrong, it'll be wonderful if the company can pull this off. It just looks like there are an awful lot of unanswered questions as to what it'll be like up at that elevation for extended periods. If I were starting up an isp based on the technology, I'd make it clear to my customers that there may be black out periods when I bring the planes down to avoid losing them to a major storm. The tradeoff is when the planes are up, they'll get terrific throughput. 98% uptime may be good enough for most people. For the 99.999 crowd, they could use the service to supplement whatever they're doing and fall back to slower circuits during a storm.

At 22:14 CST on July 6, 1989 they recorded a twin flash originating in a storm top cloud and discharging into the stratosphere.

Don't get me wrong, it'll be wonderful if the company can pull this off. It just looks like there are an awful lot of unanswered questions as to what it'll be like up at that elevation for extended periods. If I were starting up an isp based on the technology, I'd make it clear to my customers that there may be black out periods when I bring the planes down to avoid losing them to a major storm. The tradeoff is when the planes are up, they'll get terrific throughput. 98% uptime may be good enough for most people. For the 99.999 crowd, they could use the service to supplement whatever they're doing and fall back to slower circuits during a storm.

My understanding was that while astronomers decided the origin of Pluto was similar to that of other Kuiper-belt objects, its status as a planet was not disputed, or at least, left the same. This wasn't because of tradition necessarily, but because many believed that its large size (relative to other Kuiper belt objects) merited it being refered to as a planet.

"We" can't?

NASA still publishes semi-regular status reports on both Voyagers here.
--

Actually, Pioneer 10 and 11 and Voyager 1 and 2 have both cleared the solar system... well, depending on what you define as the solar system.

Pioneer 10 crossed the orbit of Neptune and passed beyond the (at the time) furthest orbiting planet on June 13, 1983 (see this page). It hasn't passed the heliopause yet (distance where the solar wind ceases), at least not that anyone can determine.

Pioneer 10 is not the probe furthest from the sun, however. Apparantly that honor goes to Voyager 1, which is moving faster and exceeded Pioneer 10's heliocentric distance on Feb 17, 1998, but it's still well over 7 billion miles away. (see http://spaceprojects.arc.nasa.gov/Space_Projects/p ioneer/PNhome.html).

One interesting thing I found while looking for this is that only Pioneer 10 is moving in the opposite direction from our solar system (relative to the galactic core). Voyager 1 & 2, as well as Pioneer 11 are moving "in front of" us, while Pioneer 10 is moving the opposite direction. This could result in some really useful information about the edges of the solar system -- except that apparantly Pioneer 10's power system is going to run out of juice in a few years (solar powered I guess - the W/m^2 will probably be too low to power the probe at that point).

And no, we're not getting pictures of Neptune or Pluto. You determine these things at time of launch -- we've been doing astronomical calculations for a few hundred years and know where the planets are going to be far ahead of time. Pioneer 10 wasn't scheduled to make a flyby of anything but Jupiter because the orbits were wrong.

And yes, it is still sending back data. As is Pioneer 6, which is still orbiting the sun at about 74 million miles (inside the Earth's orbit). But, like I said, apparantly that's not going to be much longer for Pioneer 10. Shame... but one heck of a legacy to its designers. And just think - in a couple million years we'll be able to pick it up in the vicinity of Aldebaran.

Actually, Pioneer 10 and 11 and Voyager 1 and 2 have both cleared the solar system... well, depending on what you define as the solar system.

Pioneer 10 crossed the orbit of Neptune and passed beyond the (at the time) furthest orbiting planet on June 13, 1983 (see this page). It hasn't passed the heliopause yet (distance where the solar wind ceases), at least not that anyone can determine.

Pioneer 10 is not the probe furthest from the sun, however. Apparantly that honor goes to Voyager 1, which is moving faster and exceeded Pioneer 10's heliocentric distance on Feb 17, 1998, but it's still well over 7 billion miles away. (see http://spaceprojects.arc.nasa.gov/Space_Projects/p ioneer/PNhome.html).

One interesting thing I found while looking for this is that only Pioneer 10 is moving in the opposite direction from our solar system (relative to the galactic core). Voyager 1 & 2, as well as Pioneer 11 are moving "in front of" us, while Pioneer 10 is moving the opposite direction. This could result in some really useful information about the edges of the solar system -- except that apparantly Pioneer 10's power system is going to run out of juice in a few years (solar powered I guess - the W/m^2 will probably be too low to power the probe at that point).

And no, we're not getting pictures of Neptune or Pluto. You determine these things at time of launch -- we've been doing astronomical calculations for a few hundred years and know where the planets are going to be far ahead of time. Pioneer 10 wasn't scheduled to make a flyby of anything but Jupiter because the orbits were wrong.

And yes, it is still sending back data. As is Pioneer 6, which is still orbiting the sun at about 74 million miles (inside the Earth's orbit). But, like I said, apparantly that's not going to be much longer for Pioneer 10. Shame... but one heck of a legacy to its designers. And just think - in a couple million years we'll be able to pick it up in the vicinity of Aldebaran.

I can't help but notice that some of these older space probes may have cost more in 1970's dollar's when adjusted for inflation, but if they last for 30 years there was the potential to get more for you money over the years. It certainly seem more care went into the planning than some recent missions.

nosferatu-man is right. Squid do not hunt in packs. They are solitary animals. Additionally, squid have been found in the stomachs of whale that have washed ashore. See this link, which was posted in an earlier comment.