1. The launch of Shenzhou 16 manned spacecraft was a complete success. At the China Space Station, which is about 400,000 meters above the ground, six astronauts of the Shenzhou 15 crew and the Shenzhou 16 crew work and live together. How much can the number 400 thousand be expressed in scientific notation?

2. The China Shenzhou 16 spacecraft is 8 meters long and consists of a propulsion module, a return module and an orbital module, with a total mass of 7,755 kilograms. How much is this data in scientific notation?