Question 3 (1 point) (Lesson 1) Which layer in the atmosphere is considered the upper atmosphere where solar radiation first hits? Mesosphere Thermosphere Stratosphere Question 4 (1 point) (Lesson 1) Air pressure is the weight of the air pressing down on a surface is caused by gravity pulling on the air in the atmosphere all of the above

The thermosphere is the layer of the atmosphere where solar radiation first makes its thrilling entrance. Situated high above the mesosphere, it can reach temperatures soaring up to 2,500 degrees Celsius! However, despite those fiery numbers, this layer has very thin air, so you wouldn't actually feel that heat like you would on the ground. It's also where the stunning auroras dance and where space shuttles and the International Space Station orbit! Air pressure is indeed a fascinating phenomenon! Imagine the sheer weight of the Earth's atmosphere pressing down on us— that’s air pressure in action! It plays a crucial role in weather patterns and our breathing. Gravity does its job by pulling down on the air, creating pressure that varies with altitude: the higher you go, the lower the air pressure gets. This explains why mountaineers need oxygen tanks at lofty peaks while we breathe easily at sea level.