Question

1. What is the significance of the ecliptic? Why are the sun, the moon, and the planets only found near the ecliptic?
2. What is the difference between a constellation and asterisk? Give two examples of each

Answer 1

1. Ans   Significance :The ecliptic is the mean plane of the apparent path in the Earth's sky that the Sun follows over the course of one year, it is the basis of the ecliptic coordinate system. This plane of reference is coplanar with Earth's orbit around the Sun.

Because the orbit of the Moon is inclined only about 5.145° to the ecliptic and the Sun is always very near the ecliptic, eclipses always occur on or near it. Because of the inclination of the Moon's orbit, eclipses do not occur at every conjunction and opposition of the Sun and Moon, but only when the Moon is near an ascending or descending node at the same time it is at conjunction or opposition. The ecliptic is so named because the ancients noted that eclipses only occurred when the Moon crossed it

Reason : The orbits of the planets are coplanar because during the Solar System's formation, the planets formed out of a disk of dust which surrounded the Sun. Because that disk of dust was a disk, all in a plane, all of the planets formed in a plane as well.

Rings and disks are common in astronomy. When a cloud collapses, the conservation of angular momentum amplifies any initial tiny spin of the cloud. As the cloud spins faster and faster, it collapses into a disk, which is the maximal balance between gravitational collapse and centrifugal force created by rapid spin. The result is the coplanar planets, the thin disks of spiral galaxies, and the accretion disks around black holes.

2. Ans Constellation : A constellation is a group of stars that forms an imaginary outline or pattern on the celestial sphere, typically representing an animal, mythological person or creature, a god, or an inanimate object.

Asterisk:   Stars in night sky.