sentence1: The 2 1 / 2 -ton probe will plunge into the thick Jovian atmosphere today at 3 : 49 p.m. Eastern time , disintegrating moments later from the friction generated by its 108,000-mph free-fall .
sentence2: The 2 1 / 2-ton probe will plunge into the thick Jovian atmosphere today at 1 : 49 p.m. MDT , disintegrating moments later from the friction generated by its 108,000 mph free-fall .