Hi, how can you see dwarf plannets from earth when they are dead

Question: Hi, how can you see dwarf plannets from earth when they are dead
- Keywords:
  dwarf planet,
  earth,
  space
Asked by to Sarah on 16 Jun 2014. This question was also asked by .
- Sarah Casewell answered on 16 Jun 2014:
  
  Dwarf planets like pluto are in our solar system. Pluto was discovered when astronomers noticed a dim star moving quite fast from year to year. When they measured this it turned out to be pluto!
  
  The brown dwarfs I study are bright in the infrared wavelengths (heat) so we discover them using those wavelengths. You can’t see them from earth with your eyes, but we can with telescopes.

Question: Hi, how can you see dwarf plannets from earth when they are dead