Conclusions Brown dwarfs exist. Some 8 have been discovered and many more can be expected to be confirmed in the near future. Currently, our expectations are that brown dwarfs do not make an important contribution to the missing mass. However, it must be remembered that most searches have been biased of necessity to very local areas of our galaxy.
Brown dwarfs present a number of challenges, most notably their very cool atmospheres.
As more detailed observations are made we can learn much interesting new physics. Their interiors also pose a challenge, we do not as yet fully understand the equation of state of gases at the temperatures and pressures found in brown dwarfs. If we could measure accurate masses and radii for brown dwarfs this could test our current theoretical ideas on the equation of state. With the discovery of brown dwarfs and extrasolar planets we have at last plugged a large gap in the mass spectrum of objects in the universe.