[RayChuang88]

With new, more advanced telescopes and new imaging satellites going up into space in the next 10-15 years, not only might we find an Earth-sized planet out in the Kuiper Belt, but possibly find a possible brown dwarf companion to our Sun.

But more exciting than these more "local" discoveries will be the possibility we may find rocky crust planets orbiting stars up to 250 light years away with an atmosphere of oxygen, nitrogen and water vapor--the first Earth-like planets outside our Solar System.

[SunkenCiv]

The possibility of a brown dwarf companion has been raised and then “ruled out” a number of times, particularly since the Nemesis hypothesis emerged to try to make random asteroid strikes on Earth into something nice and uniform and predictable. So I give up. My own guess has been that there’s a largish planet but that its orbit is out of the ecliptic, and/or retrograde.