What are the white reflections on Ceres? What are the white reflections on Ceres?

https://solarsystem.nasa.gov/planets/dwarf-planets/ceres/overview/
According to the Wikipedia page linked by @BowlOfRed, they're ice and/or salt.


  a material with a high level of reflection, and [the scientists] suggested ice and salt as possibilities.
  
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  On 9 December 2015, scientists reported that the bright spots on Ceres may be related to a type of salt, particularly a form of brine containing hydrated magnesium sulfate (MgSO4·6H2O); the spots were also found to be associated with ammonia-rich clays. Arizona State University scientists have proposed that the bright spots are best explained as resulting from briny water erupted from Ceres's interior that subsequently sublimated, leaving behind only the salt deposits. Near-infrared spectra of these bright areas are consistent with a large amount of sodium carbonate, (Na2CO3) and smaller amounts of ammonium chloride (NH4Cl) or ammonium bicarbonate (NH4HCO3). These materials have been suggested to originate from the recent crystallization of brines that reached the surface from below.