Jules Verne 
Off On A Comet! A Journey Through Planetary Space 

The story opens when a comet named Gallia collects a few tiny bits of Earth while passing by it in midair. The disaster occurred close to Gibraltar on January 1st, 1885. There are still 36 people in the territory the comet has occupied who are of French, English, Spanish, and Russian nationalities. At first, they don't know what's happened and think there's been an earthquake instead of a collision. Adjutant Ben Zoof for Captain Servadac surprises himself by jumping 12 meters (39 feet) in the air as the first indication of weight loss. Soon after, Zoof and Servadac also observe that there are only six hours between day and night, that east and west have switched places, and that water begins to boil at 66 °C (151 °F), from which they correctly deduce that the atmosphere has thinned and the pressure has reduced. They observe the Earth and the Moon when they first arrive at Gallia, but they incorrectly think it is a newly discovered planet. Their research expedition, which included a ship that the comet also captured, produced additional important data.