Universe and the Earth Test - 2

The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System. A parsec is defined as the distance at which one astronomical unit subtends an angle of one arcsecond, which corresponds to 648000π astronomical units.

Light travels through space at just over 1,86,000 miles per second. The Moon is just under 2,50,000 miles from Earth, so light from the Moon's surface has to travel more than one second (about 1.3 seconds) to reach us.

The brightest star in the sky is Sirius, also known as the Dog Star or, more officially, Alpha Canis Majoris, for its position in the constellation Canis Major. Sirius is a binary star dominated by a luminous main sequence star.

Lunar eclipse is caused when Earth comes between Sun and Moon. This causes the shadow of Earth to fall on Moon, either partially or completely, making it go dark for sometime.

A solar eclipse occurs when the moon gets between Earth and the sun, and the moon casts a shadow over Earth. A solar eclipse can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface.

Tides are caused by the gravitational pull of moon on earth.
On a full moon gravitational pull is the maximum.

Venus, which is the second planet from the sun, has a temperature that is maintained at 462 degrees Celsius. It is the hottest planet in our solar system. Mercury, which is nearest to the sun, has no atmosphere, due to which all the solar radiation escapes into the space. However, Venus has an atmosphere which is primarily composed of carbon dioxide, a greenhouse gas; due to this, solar radiation could not escape from its atmosphere and makes it even more hotter.

pole star lies in the axis of spin of Earth

size of the shadow of moon on earth is small as compared to cross-section of earth