The gravitational kick from a passing star might send such an ice dwarf into the inner solar system -- and nearer our view -- just once every 10 million years.
Several observational techniques, some more promising than others, might reveal an ice dwarf lurking here, he says.
Any of these could have a close encounter with an ice dwarf.
Scanning the heavens with highly sensitive, widefield infrared telescopes should prove more fruitful, says Levison, because the ice dwarfs would reflect heat (infrared energy) more readily than visible light.
Stern calculates that a few of the ice dwarfs formed between Uranus and Neptune might have been ejected by gravity into the inner solar system.
A thorough examination of these disks, including their size and density, may one day indicate whether they contain ice dwarfs.
An unusual division offers Mercury and Venus in HOT PLANETS (0778737357), Jupiter and Saturn in MIGHTY MEGAPLANETS (0778737373), Pluto and beyond in ICE DWARFS (0778737365) and Neptune and Uranus in GAS GIANTS (0778737349), comparing the properties of similar planets in our solar system and providing vivid, eye-catching covers and color photos throughout in these whirlwind tours of our solar system.
You have the four rocky planets, including the Earth, the gas giants like Jupiter and Saturn, and then you've got ice dwarfs
which would include Pluto and other large Kuiper Belt objects.