Back in the 70’s Ben Bova (then the editor of Analog magazine) along with Trudy Bell, produced a wonderfully illustrated book caled Close Up: New Worlds that billed itself as “astounding modern views of the solar system”.
Well, that was 1977. To date it is to note that it includes Pluto among the planets.
I used that book as a resource while designing SF strategy board games. It was a great compendium of both known fact and SF speculation.
NASA and other space agencies have taken a lot more pictures since then with Hubble, other space telescopes and a huge variety of probes either taking up orbits or doing fly-bys.
Lets just say it’s been a while since anyone has taken a grand tour the way that Ben and Trudy did back in ’77. So we’re going to reprise that book using the latest and greatest.
Ceres one of a handful, if not the only, “dwarf planet” orbiting between Mars and Jupiter.
Since the demotion of Pluto, a lot of discussion has gone into the notion of dwarf planets. The basic definition is a body that has sufficient mass to pull itself into hydrostatic equilibrium, meaning it is spherical, or nearly so.
The majority of dwarf planets are “Trans-Neptunian”, orbiting out past Neptune and/or in the Kuiper belt.
Dwarf planets may range in diameter from nearly 1500 miles (Ceres’ diameter is 587 miles) down to perhaps 187 miles.
Ceres’ orbits 257 million miles from the Sun; Pluto, now classified as a dwarf planet, orbits some 3.67 billion miles out, while Eris, now the most distant dwarf planet discovered, orbits at some 90 billion miles from the Sun.
Ceres’ year is 1,682 days; Pluto, 248 years; Eris, 558 years
Dwarf planets may be icy, rocky or both.
NASA has a wonderful planetary information resource. You can learn far more about Mars here