Objects which orbit the sun, which are not considered a planet or a moon, are in modern terms a Minor Planet or a planetoid. [note: It is possible for minor planets to have their own moon(s), such as the case of 243 Ida In 1801 the first minor planet was discovered and it was called Ceres Ferdinandea (though more commonly simply called Ceres), since then more then 204,000 minor planets have been discovered. Each minor planet has the potential to impact other bodies, including moons and planets, including ours. Freeware: CMTWIN32[source] PROGRAMMA COMETE & ASTEROIDI V6.01[source] Comewin V1.0[source] MPCOrb[source] Orbitas[source] EQAlign 2.2.5 beta[source]