Two questions which arises in my mind about aurora borealis are:
- Why does aurora borealis occur?
- Why does aurora borealis occur in a particular time of the year?
Answers:
- As solar wind approaches the Earth, it meets the Earth's magnetic field. In the ionosphere, the ions of the solar wind collide with atoms of oxygen and nitrogen from the Earth's atmosphere. The energy released during these collisions causes aurora borealis.
- Aurora borealis is active the whole year. Since it needs to be dark in order to see aurora borealis in the sky, late August/September through the very beginning of April is the best time to go to a destination located in the aurora zone for a chance to see them.
Note: These are the questions which arises in my mind only. It may differ from person to person.
Hope you could understand.
If you have any query, feel free to ask.
Oceanic crust is more dense which makes it subduct and continental crust is less dense which makes it override the oceanic crust during subduction
Answer:
The Sahel is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna to the south. Having a semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea. Wikipedia
Area: 1.179 million mi²
The Sahel has a tropical, hot steppe climate (Köppen climate classification BSh). The climate is typically hot, sunny, dry and somewhat windy all year long. The Sahel's climate is similar to, but less extreme than, the climate of the Sahara desert located just to the north.
Explanation:
Respiration of carbon dioxide by plant roots can lead to the formation of carbonic acid which can chemically attack rocks and sediments and help to turn them into soils. There are a whole range of weathering processes at work near the surface of the soil, acting together to break down rocks and minerals to form soil.
