In 2001, the most precise measurement yet of the isotopic signatures of moon rocks was published.[4] Surprisingly, the Apollo lunar samples carried an isotopic signature identical to Earth rocks, but different from other Solar system bodies. Because most of the material that went into orbit to form the Moon was thought to come from Theia, this observation was unexpected. In 2007, researchers from Caltech showed that the likelihood of Theia having an identical isotopic signature as the Earth is very small (<1 percent).[9] Published in 2012, an analysis of titanium isotopes in Apollo lunar samples showed that the Moon has the same composition as Earth,[10] which conflicts with the Moon forming far from Earth's orbit.