The pathogenesis of ectopic gastric mucosa is a matter of debate between a congenital-embryological-and an acquired origin-consecutive to a gastroesophageal reflux (GER) like Barrett's esophagus -, the most commonly accepted theory being that these areas are embryological remnants.
Standard size latex filled helium balloons stay afloat for approx 8 - 12 hours, metallic helium filled balloons float for 2-5 days. I have found that a 36 latex helium filled balloon can stay afloat for a number of days due to the thickness of the balloon and the massive quantity of helium.
In this case, the helium balloon that you hold by a string is floating in a. pool of air (when you stand underwater at the bottom of a swimming. pool, you are standing in a pool of water maybe 10 feet deep -- when. Center for Cosmological Physics 2002 Yerkes Winter Institute Balloon Laboratory - 2.