Definition of planet object can be irregular in shape, but beyond that point gravity begins to pull an object towards its own centre of mass until the object collapses into an ellipsoid. (None of the large objects of the Solar System are truly spherical. Many are spheroids, and several, such as the larger moons of Jupiter and Saturn and the dwarf planet , have been further distorted into ellipsoids by rapid rotation or tidal forces, but still in hydrostatic equilibrium.) However, there is no precise point at which an object can be said to have reached hydrostatic equilibrium. As Soter noted in his
Solar art prize Solar art prize The Solar art prize is an annual art exhibition hosted by the Royal Society of the Arts, South Australia. The prize was established by Pip Fletcher in 2010, and has consistently invited artists to respond to the subject of climate change. The event's recurring theme is "Caring for Our Planet". Artists are invited to submit new works for consideration, and various prizes are offered. Prizes include cash and sponsor offerings, including tens of thousands of dollars in credits to be redeemed on solar power system services and installations, which include solar panels, hot water systems and batteries.