# Mirror Matter

A new preprint on the mirror matter hypothesis by R. Foot and
T.L. Loon has appeared.  My observation that cratering rates on the Moon
point to the presence of mirror asteroids in our solar system is also
included.

See:

http://xxx.lanl.gov/abs/astro-ph/0203152

Abstract:

There are a number of very puzzling meteoritic events including (a) The
Tunguska event. It is the only known example of a low altitude atmospheric
explosion. It is also the largest recorded event. Remarkably no fragments or
significant chemical traces have ever been recovered. (b) Anomalous low
altitude fireballs which (in some cases) have been observed to hit the
ground. The absence of fragments is particularly striking in these cases,
but this is not the only reason they are anomalous. On the other hand, there
is strong evidence that most of our galaxy is made from exotic dark
material - dark matter'. Mirror matter is one well motivated dark matter
candidate, since it is dark and stable and it is required to exist if
particle interactions are mirror symmetric. If mirror matter is the dark
matter, then some amount must exist in our solar system. We demonstrate that
the mirror matter theory allows for a simple explanation for the puzzling
meteoritic events [both (a) and (b)] if they are due to mirror matter
space-bodies. A direct consequence of this explanation is that mirror matter
fragments should exist in (or on) the ground at various impact sites. The
properties of this potentially recoverable material depend importantly on
the sign of the photon-mirror photon kinetic mixing parameter, $\epsilon$.
We argue that the broad characteristics of the anomalous events suggests
that $\epsilon$ is probably negative. Strategies for detecting mirror matter
in the ground are discussed.

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