EVERYDAY SCIENCE

Detailed explanation-1: -SILURIAN SILURIAN also contains salt, gypsum, and hematite.

Detailed explanation-2: -Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200, 000 to 300, 000 years, although it has been more than twice that long since the last reversal. A reversal happens over hundreds or thousands of years, and it is not exactly a clean back flip.

Detailed explanation-3: -It’s tilted about 23.5 degrees relative to our plane of orbit (the ecliptic) around the Sun. As we orbit our Sun, our axis always points to the same fixed location in space. Our northern axis points almost directly toward Polaris, the North Star. This picture shows Earth from its side as it orbits our Sun.