EVERYDAY SCIENCE

Detailed explanation-1: -Answer: The answer is Option 2: Earth rotates on its axis.

Detailed explanation-2: -Earth rotates around this line, like a spinning top. Polaris is located quite close to the point in the sky where the north rotational axis points – a spot called the north celestial pole. As our planet rotates through the night, the stars around the pole appear to rotate around the sky.

Detailed explanation-3: -This wobbling motion of Earth on its axis is called precession. Because of precession, Polaris and Vega alternate as the North Star every 13, 000 years.

Detailed explanation-4: -We call that star the “North Star” since it sits in the direction that the spin axis from the northern hemisphere of Earth points. At present, the star known as Polaris is the North Star. However, Polaris has not always been the North Star and will not always be the North Star.

Detailed explanation-5: -However the North Star has not always been, nor will it always be, the Pole Star. This is because the Earth’s axis changes slightly over time and stars move in relation to each other over time. In the year 3000 B.C.E, the North Star was different. It was called Thuban (also known as Alpha Draconis).