... The Planet, the White Dwarf, and the Neutron Star . ... A planet, a white dwarf, and a neutron star orbit each other in the giant globular star cluster M4, some 5,600 light-years away. The most visible member of the trio is the white.. ... Mars is heading for its closest encounter with Earth in over 50,000 years. Although Mars and Earth continue in their normal orbits around the Sun, about every two years Earth and Mars are on the same part of their orbit as seen from the Sun. ...