Hi Mark -

You seem to have missed Marsden's comment from the Washington Post article on the new estimate, which supercedes the earlier NeoDys estimate:

"You don't know what the gravitational effect of the Earth will be," said Brian G. Marsden, who oversees the hunt for near-Earth objects as director of the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics.

"In 2029, the [close encounter with] Earth will increase the size of the orbit, and the object could get into a resonance with the Earth," he added. "You could get orbit matchups every five years or nine years, or something in between." In fact, 2004 MN4 could come close again in 2034, 2035, 2036, 2037, 2038 or later."

I had thought that the NeoDys team had earlier calculated gravitational perturbation of 2004 MN4's orbit. (Without Bob Kobres running the Cambridge Conference archive, I can no longer locate the earlier statements.) Marsden's comment indicates that I was mistaken. (Thankfully, calculating these effects is not my job. If you've noticed, I've been making a lot of mistakes recently.)

2004 MN4 is going to pass under the geosynchronous satellites in 2029. My assumption is that the system will try to seek gravtitational equilibrium over time: in other words, barring some other effect, 2004 MN4 will tend to combine with the Earth.

2004 MN4 has been considered for some time now. Given Marsden's abilities, if he is not happy with the current state of the estimates of the gravitational effects, then those estimates are inadequate. If Marsden is concerned with the impact hazards from 2004 MN4 for the out years from 2029, then they need to be looked at quite closely.

I believe these tasks will require more resources than currently available. Given those resource needs, I can't imagine why an alert to the political leadership has not been issued yet - for that matter, I don't know if it already has.

we'll see -
ep