Question

1. Explain the composition of the atmosphere. (AS)​

Answer 1

The Earth’s atmosphere is composed of the following molecules: nitrogen (78%), oxygen (21%), argon (1%), and then trace amounts of carbon dioxide, neon, helium, methane, krypton, hydrogen, nitrous oxide, xenon, ozone, iodine, carbon monoxide, and ammonia. Lower altitudes also have quantities of water vapor.

The atmosphere we have today is very different from the Earth’s early atmosphere. When the planet first cooled down 4.4 billion years ago, volcanos spewed out steam, carbon dioxide and ammonia, and it was 100 times as dense as today’s atmosphere.