chongo's Journal: J002E3 - Complex orbit example

Sometimes the orbit of an object can be very complex, particularly in close approach situations. A good example is the recently discovered object that is believed to be part of the Apollo 12 S-IVB third stage .

In this orbit diagram you can watch J002E3 being pulled into a 6 orbit pass of Earth. There is a static image of the 6 orbit pass as well.

The object comes in from the left having been orbit around the sun. The Earth comes close to J002E3 near its solar apogee .

At first you see J002E3 approach the Lagrangian point L1.

L1, is the point that lies on a line that runs through the center of mass of the Earth and Sun. L1 is a the point where the Earth and Sun's gravitational pull balance.

J002E3's momentum caries it past L1 and down into Earth's gravity well. Inside Earth's gravity well "bowl", J002E3 takes 6 rolls around the rim.

Partly influenced by the Moon, the orbits swing around until the 6th apogee carries it toward L1 again. Then, just like it entered Earth's gravity well, J002E3 heads back toward an orbit around the Sun.

It is likely that J002E3 will have another temporary capture encounter with the Earth sometime in the future when, for a brief period of time, it will become Earth's third moon.

``Third moon? What is Earth's second moon?''

The 2nd moon of Earth is an asteroid called 3753 Cruithne . It has a very unusual and complex orbit as well.