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.
Generally it takes longer than 15 seconds to be down, but it happens. here one guy going down during his basic training graduation, and there are many many many many more videos out there of it happening. It's one of the first things people are supposed to learn when standing in formation.. don't lock your knees. I saw 2 hit the deck in JROTC as a kid in one ceremony. The only thing you can do is stand there as the person next to you falls.