The scientists on the project theorized that aiming the TPF at a red dwarf star might yield the best opportunities for seeing smaller planets. Due to the slow rate at which they burn hydrogen, red dwarfs have an enormous estimated lifespan; allowing plenty of time for life to evolve on surrounding planets. Also, red dwarves are very common in the universe. Therefore, if they support habitable planets, it substantially increases the chances of finding life in the universe. However, being much dimmer than other stars, it will be harder to detect planetary systems around them. In addition, lower gravity would limit the potential size of a system. The discovery of Gliese 581 g raises hopes of finding more red dwarf systems, including potentially habitable ones.