Final Product (FOIA 23-F-0010)

material composition. The inferred material strengths of 194 Mega-Pascals (MPa) for IM1 and 75 MPa
for IM2 imply that both were tougher than iron meteorites, which have a maximum yield strength of
50 MPa.
IM1 and IM2 ranked number 1 and 3 in the distribution of material strengths among all 273 meteors
in the CNEOS catalog > . The probability of
drawing the material strength ofthe first and second interstellar meteors out of the familiar
population of Solar system rocks is roughly the square of (3/273), or equivalently one part in 10,000.
This means that the population of interstellar meteors is different from Solar system meteors at the
99.99% confidence level. This conclusion is corroborated by fitting the distribution ofCNEOS meteors
with a Gaussian shape in the logarithm of material strength. Both IM1 and IM2 lie on the far tail of
the distribution, at 2.6 and 3.5 standard deviations away from the mean, making their combined
likelihood less than a part in a million.
This tantalizing conclusion about the extremely rare material strength of IM1 and IM2, implies that
interstellar meteors are not rocks from planetary systems like the Solar systems.
The Earth collides with interstellar objects along its orbit around the Sun. The simplest assumption to
make is that these objects arrive into the Solar system on random trajectories in the Local Standard of
Rest. Based on the detection rate of IM1 and IM2 in the CNEOS catalog, roughly once per decade, one
can infer that about 40% of all refractory elements > in the Milky-Way galaxy are locked in meter-scale interstellar objects. This
extraordinarily high abundance again seems to defy a planetary system origin.
Interestingly, a paucity of refractory elements is observed in the gas phase in the interstellar medium,
an observation which could potentially reflect refractory elements being locked in interstellar objects.
Supernovae have been observed to produce iron-rich "bullets", which could be a possible origin of IM1
and IM2. In particular, X-ray imaging of the Vela supernova remnant revealed > bow shocks from bullets flying
out ofthe explosion site, a discovery that I attempted to explain > three decades ago. It is possible that IM1 and IM2 were shot out of an exploding
star.
But it is also possible that IM1 and IM2 move fast and are tough because they are artificial in origin,
namely chemically-propelled interstellar spacecraft like our own interstellar probes < Caution-
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