Brown dwarfs or failed stars are stars with about one eighth of the Sun's mass and just not big enough to start fusion process. They are almost impossible to detect in the visual spectrum but they show off well in the infrared.If all goes like the simulations performed at Cal-Tech then dozens of brown dwarfs should be found within 25 light years of Earth. These are important to science to answer questions about how our Universe formed in general and how star formation happens or does not happen in the case of brown dwarfs.
Very bright galaxies are also on the menu as WISE maps the entire sky. When galaxies collide, they occasionally produce large numbers of stars as dust and gasses condense. This whole process produces lots of infrared light,and WISE will be there to take it all in. It takes hundreds of millions of years for galaxies to collide, so scientists will just get to see a slice of the process. With such an all-encompassing scan, researchers hope to see thousands of dust discs condensing around stars, these corrolate to young planetary systems.
Other items to scan for will be dark asteroids. Dark asteroids present a hazard to Earth in the form of a run in.These asteroids do not reflect light very well and because of this, cannot be picked up in a telescope.There are estimated 100,000 of these Asteroids orbiting undetected. WISE will be able to see these Astro-boulders because they absorb the Sun's heat and then reflect it in the infrared.This wide-field surveyor will map where they are and then it can be determined if they are a threat to Earth.