Stability of the Solar System one point, the two may fall into sync, at which time Jupiter's constant gravitational tugs could accumulate and pull Mercury off course with 1–2% probability, 3–4 billion years into the future. This could eject it from the Solar System altogether or send it on a collision course with Venus, the Sun, or Earth. Another example is Earth's axial tilt which, due to friction raised within Earth's mantle by tidal interactions with the Moon (see below), will be rendered chaotic at some point between 1.5 and 4.5 billion years from now. Objects coming from outside the solar system can also affect
Solar System disc-like regions of cosmic dust. The first, the zodiacal dust cloud, lies in the inner Solar System and causes the zodiacal light. It was likely formed by collisions within the asteroid belt brought on by gravitational interactions with the planets. The second dust cloud extends from about 10 AU to about 40 AU, and was probably created by similar collisions within the Kuiper belt. The inner Solar System is the region comprising the terrestrial planets and the asteroid belt. Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius