2004 MN4 risk fades away.

I am unable to get the actual updated orbital elements
right now (hmm... overloaded webservers...) but the JPL
NEO webpage now is indicating that today's latest updates
put the risk of 2004 MN4 hitting earth way way down.

Most of the potential encounters have apparently stopped
being potential impacts, and the highest Torino scale for
the remaining possible impacts is 0.

Remaining possible impacts are in 2037, 2044, 2048, 2068,
2070, 2078, 2092, and 2096, with a culminative impact
probability of 1.8E-05.


-george william herbert

On Mon, 27 Dec 2004 23:12:24 +0000, George William Herbert wrote:
I am unable to get the actual updated orbital elements
right now (hmm... overloaded webservers...) but the JPL
NEO webpage now is indicating that today's latest updates
put the risk of 2004 MN4 hitting earth way way down.

Most of the potential encounters have apparently stopped
being potential impacts, and the highest Torino scale for
the remaining possible impacts is 0.

Interesting -- I see this new set of numbers is based on 118
observations, down from the 176 observations that resulted in
the earlier assessment. Is this due to a different method
of identifying outliers, or perhaps a much more accurate
observation (Arecibo??) that rules out some of the optical ones?
Or what?
--
Jim Gillogly

Jim Gillogly wrote:
On Mon, 27 Dec 2004 23:12:24 +0000, George William Herbert wrote:
I am unable to get the actual updated orbital elements
right now (hmm... overloaded webservers...) but the JPL
NEO webpage now is indicating that today's latest updates
put the risk of 2004 MN4 hitting earth way way down.

Most of the potential encounters have apparently stopped
being potential impacts, and the highest Torino scale for
the remaining possible impacts is 0.

Interesting -- I see this new set of numbers is based on 118
observations, down from the 176 observations that resulted in
the earlier assessment. Is this due to a different method
of identifying outliers, or perhaps a much more accurate
observation (Arecibo??) that rules out some of the optical ones?
Or what?

I don't know for sure. I've been trying to get to the
more detailed info websites and getting http timeouts.


-george william herbert

George William Herbert wrote:
Jim Gillogly wrote:
On Mon, 27 Dec 2004 23:12:24 +0000, George William Herbert wrote:
I am unable to get the actual updated orbital elements
right now (hmm... overloaded webservers...) but the JPL
NEO webpage now is indicating that today's latest updates
put the risk of 2004 MN4 hitting earth way way down.

Most of the potential encounters have apparently stopped
being potential impacts, and the highest Torino scale for
the remaining possible impacts is 0.

Interesting -- I see this new set of numbers is based on 118
observations, down from the 176 observations that resulted in
the earlier assessment. Is this due to a different method
of identifying outliers, or perhaps a much more accurate
observation (Arecibo??) that rules out some of the optical ones?
Or what?

I don't know for sure. I've been trying to get to the
more detailed info websites and getting http timeouts.


Ok, got through.


NeoDys has not updated since early today local Italy time
(many hours ago US time); they still had the high probability
2.6E-2 probability in the 2029 encounter.

URLs for those who want to see for themselves:
http://newton.dm.unipi.it/cgi-bin/ne...s:2004MN4;risk
http://newton.dm.unipi.it/cgi-bin/ne...s:2004MN4;main



Current NASA ephimerides for 2029 are for a miss distance of
63,000 km (0.00043 AU) at closest approach around 2200 UT.

http://neo.jpl.nasa.gov/cgi-bin/db?name=2004+MN4

Click on the "high accuracy ephemeris" link in the middle of the page.

It's not clear what set of observations lead to that change,
or what the difference is between the NeoDys data and JPL.



-george william herbert

In article ,
Jim Gillogly wrote:

Interesting -- I see this new set of numbers is based on 118
observations, down from the 176 observations that resulted in
the earlier assessment. Is this due to a different method
of identifying outliers, or perhaps a much more accurate
observation (Arecibo??) that rules out some of the optical ones?

My recollection is that the 176 were taken over 190 days,
the current 139 were taken over 287 days, so it must have
been identified in earlier images.
--
Urban Fredriksson http://www.canit.se/%7Egriffon/
A weapon is a device for making your enemy change his mind.

Current NASA ephimerides for 2029 are for a miss distance of
63,000 km (0.00043 AU) at closest approach around 2200 UT.


That is inside the orbit of the Moon. Do you think there is a chance that by
2029, we'll be able to slow it down and capture it in a circular orbit about
63,000 km high? If it's in such an orbit around Earth instead of the Sun, it
will never threaten Earth again, and if its 300 meters in diameter, there
should be enough material there to build a space colony and perhaps a few Solar
Power Satellites. What sort of asteroid is it?

In article ,
Tkalbfus1 wrote:
Current NASA ephimerides for 2029 are for a miss distance of
63,000 km (0.00043 AU) at closest approach around 2200 UT.

That is inside the orbit of the Moon. Do you think there is a chance that by
2029, we'll be able to slow it down and capture it in a circular orbit about
63,000 km high? If it's in such an orbit around Earth instead of the Sun, it
will never threaten Earth again, and if its 300 meters in diameter, there
should be enough material there to build a space colony and perhaps a few Solar
Power Satellites. What sort of asteroid is it?

Well, technically if it's parked lower than geosynch it will
pull a Phobos on us and de-orbit. That will (probably, depending on
the orbit) take a very long time as humans measure things.
--
http://www.cic.gc.ca/english/immigrate/
http://www.marryanamerican.ca
http://www.livejournal.com/users/james_nicoll

In article ,
Tkalbfus1 wrote:
Current NASA ephimerides for 2029 are for a miss distance of
63,000 km (0.00043 AU) at closest approach around 2200 UT.


That is inside the orbit of the Moon. Do you think there is a chance that by
2029, we'll be able to slow it down and capture it in a circular orbit about
63,000 km high? If it's in such an orbit around Earth instead of the Sun, it
will never threaten Earth again, and if its 300 meters in diameter, there
should be enough material there to build a space colony and perhaps a few Solar
Power Satellites. What sort of asteroid is it?

NASA estimates the mass as 1.3x10^8 tonnes. I _think_ our largest
year for launches was 600 tons in 1968, or about 1/200,000th the mass of
2004 MN4. The ISS is, I think, something under 200 tonnes.

I have no idea what type it is but I could see uses for several
types.



--
http://www.cic.gc.ca/english/immigrate/
http://www.marryanamerican.ca
http://www.livejournal.com/users/james_nicoll

Tkalbfus1 wrote:
Current NASA ephimerides for 2029 are for a miss distance of
63,000 km (0.00043 AU) at closest approach around 2200 UT.


That is inside the orbit of the Moon. Do you think there is a chance that by
2029, we'll be able to slow it down and capture it in a circular orbit about
63,000 km high? If it's in such an orbit around Earth instead of the Sun, it
will never threaten Earth again, and if its 300 meters in diameter, there
should be enough material there to build a space colony and perhaps a few Solar
Power Satellites. What sort of asteroid is it?

It would be technically possible for us to do this, but it's going to be
a major undertaking.
You're looking at a delta-v of around 10Km/s.

Comparing the task with making an asteroid miss the earth, if started on
a year out, a task which needs a delta-v of around 0.5m/s, this is 1/20000th
the speed, or enough to make an 8Km asteroid miss earth.

In article ,
Ian Stirling wrote:
Tkalbfus1 wrote:
Current NASA ephimerides for 2029 are for a miss distance of
63,000 km (0.00043 AU) at closest approach around 2200 UT.


That is inside the orbit of the Moon. Do you think there is a chance that by
2029, we'll be able to slow it down and capture it in a circular orbit about
63,000 km high? If it's in such an orbit around Earth instead of the Sun, it
will never threaten Earth again, and if its 300 meters in diameter, there
should be enough material there to build a space colony and perhaps a few Solar
Power Satellites. What sort of asteroid is it?

It would be technically possible for us to do this, but it's going to be
a major undertaking.
You're looking at a delta-v of around 10Km/s.

Its orbit crosses that of Venus, yeah? Any chance of exploiting
that for useful delta vee?

Earth is such a useful resource for this sort of thing but
I just bet if we proposed a Venus encounter followed by a 200 km
miss of the Earth, people would be all megadeath this and megadeath
that and mentioning of old sigfiles about aero and lithobraking.
--
http://www.cic.gc.ca/english/immigrate/
http://www.marryanamerican.ca
http://www.livejournal.com/users/james_nicoll