Eris' size resulted in its discoverers and NASA labelling it the solar system's tenth planet. This, along with the prospect of other similarly sized objects being discovered in the future, stimulated the International Astronomical Union (IAU) to define the term planet more precisely. Under a new definition approved on August 24, 2006, Eris was designated a dwarf planet along with Pluto and Ceres.
Best Answer: it depends on a few things~...but the longest time a human can stay upside down is 2 days.. If your heart is reasonably healthy and you aren't restricted, then you shouldn't pass out at all, any more than you would laying down or standing up.
1 Stage N4: The final stage of sleep is REM sleep, or dream sleeping. 2  This occurs about 70 to 90 minutes after falling asleep. 3  You will likely experience rapid eye movement, shallow breathing, and your heart rate and blood pressure may increase. 4  During this stage, your arms and legs are also paralyzed.