I believe that the greatest potential for danger will come in the form of TU24 being an asteroid whose plasma discharge with Earth may cause great chaos, even though it is hundreds of thousands of kilometers away.
Plasma is the fourth state of matter, and one that we know little about. 99.999% of the universe consists of this plasma.
Astronomers hold the theoretical assumption that bodies in space are electrically neutral. An electric comet or asteroid would strike at the foundations of the theoretical sciences. A few months ago, a surprise happened.
On October 24th, 2007, Comet Holmes was the largest object in our solar system. 42% larger than our sun. For no apparent reason, it erupted from a very dim magnitude 17 to about magnitude 2.5 and its coma expanded to 2,000,000 km diameter.
The unpredictable behavior from Comet Holmes can be explained by the breakdown of the plasma sheath that forms around a charged body in space. A plasma sheath insulates the charged body from the charge of the plasma outside it. Across the wall of the sheath, called the "double layer," there is a strong electric field. But when that wall breaks down, the result can be an explosive instability with accompanying electric discharge.
Because of Comet Holmes just a few months ago, scientists are starting to seriously consider the 'electric universe', or plasma cosmology.
Plasma Cosmology acknowledges the electrodynamic nature of all things in the universe. In this non-mechanical view, gavity and inertia are joined by other forces to create the universe we know (and don't know). Plasma is not electrically neutral, but is a superconductor that can carry electrical charges throughout the solar system.
IT IS POSSIBLE that asteroid 2007 TU24 is negatively charged like Holmes and will react when it enters our magnetosphere in a few days.
According to plasma cosmology, the difference in the electrical potential between Earth and TU24 will result in a plasma discharge between the two when TU24 reaches Earth's magnetosphere (as it is destined to do, from the calculations).
The question is, is it charged like Comet Holmes?
I believe if TU24 affects us, it will most likely be in this way. The chances of TU24 being a negatively-charged asteroid and hitting our magnetosheath is greater than the chances of a direct impact with Earth. Our magnetosheath extends a minimum of 65,000km in the direction of the sun, and even further out in the direction opposite the sun.
Here's what the sheath looks like: http://www.mpi-hd.mpg.de/dustgroup/~...h/Image241.gif
Videos about the electric universe: