Science MCQs

Aphelion is the point in Earth's orbit where it is farthest from the Sun.

A binary star system consists of two stars gravitationally bound to and orbiting each other.

The Big Bang Theory is the prevailing cosmological model for the origin of the universe.

The Celestial Equator is the projection of the Earth's equator onto the celestial sphere.

A sidereal month (about 27.3 days) is the time the Moon takes to complete one orbit relative to the fixed stars.

In 2006 the IAU defined a planet as an object that has cleared its neighborhood around its orbit. Pluto shares its orbit with other objects in the Kuiper belt.

Retrograde motion is the apparent temporary backward motion of a planet in the sky caused by the Earth overtaking it in its orbit.

Weight depends on gravitational acceleration (g), which decreases slightly with increasing distance from the Earth's center of mass.

The ecliptic plane is the imaginary flat surface defined by Earth's orbital path around the Sun.

Stellar parallax, the apparent shift of nearby stars against the background of distant stars, is direct observational proof of Earth's revolution around the Sun.