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.
After you eat, it takes about  six to eight hours for food to pass through your stomach and small intestine. Food then enters your large intestine (colon) for further digestion, absorption of water and, finally, elimination of undigested food. In the 1980s, Mayo Clinic researchers measured digestion time in 21 healthy people. Total transit time, from eating to elimination in stool, averaged 53 hours (although that figure is a little overstated, because the markers used by the researchers passed more slowly through the stomach than actual food).