Astronomy Quiz: Meteors and Planets

Meteoroids and Meteorites

• Meteoroids are fragments of rocks that come towards the Earth, formed due to collisions among asteroids.
• Meteoroids that do not burn up completely in the Earth's atmosphere and land on the Earth are called meteorites.
• Meteorites are composed of a nickel-iron alloy (10% nickel and 90% iron) and silicate minerals.

Classification of Planets

• Inner Planets: Mercury, Venus, Earth, and Mars, also known as Terrestrial or Rocky planets, are closer to the Sun.
• Outer Planets: Jupiter, Saturn, Uranus, and Neptune, also known as Jovian or Gaseous planets, are farther away from the Sun.

Dwarf Planets

• A dwarf planet is a celestial body in direct orbit of the Sun, massive enough to be controlled by gravitational forces, but has not cleared its neighborhood.
• Examples of dwarf planets: Pluto, Ceres, Eris, Makemake, and Haumea.

Astronomical Units

• A light year is the distance light travels in one year at a speed of 3 × 10^8 m/s.
• An astronomical unit (AU) is the mean distance between the Earth and the Sun.

Earth's Structure

• The Earth is an oblate spheroid, slightly flattened at the poles and bulging at the equator.
• The Earth's perihelion is the nearest position to the Sun, and its aphelion is the farthest position from the Sun.

The Moon

• The Moon's diameter is approximately 3476 km.
• The Moon's average distance from the Earth is approximately 384,365 km.
• The Moon's rotation speed is 27 days, 7 hours, 43 minutes, and 11.47 seconds.
• The time taken by moonlight to reach the Earth is 1.3 seconds.

The Solar System

• The solar system consists of the Sun, eight planets, their satellites, and thousands of smaller heavenly bodies like asteroids, comets, and meteors.
• The Sun is at the center of the solar system, and all bodies revolve around it.
• The Sun is the nearest star to the Earth.

Facts about the Sun

• The Sun's average distance from the Earth is approximately 149,598,900 km.
• The Sun's diameter is approximately 1,391,980 km.
• The Sun's core temperature is approximately 15,000,000°C.
• The Sun's rotation speed is 25.38 days (with respect to the equator) and 33 days (with respect to the poles).
• The time taken by sunlight to reach the Earth is 8 minutes and 16.6 seconds.

Interesting Facts about the Universe

• Jupiter is the biggest planet.
• Ganymede (Jupiter) is the biggest satellite.
• Earth is the blue planet.
• Uranus is the green planet.
• Venus is the brightest planet.
• Sirius (Dog Star) is the brightest planet outside the solar system.
• Proxima Centauri is the closest star to the solar system.
• Neptune is the coldest planet.
• Venus is the morning star and evening star.
• Neptune is the farthest planet from the Sun.
• Jupiter has the maximum number of satellites.
• Saturn has the fastest revolution in the solar system.
• Mercury is the hottest planet.
• Mercury is the densest planet.
• Mercury has the fastest rotation in the solar system.
• Deimos (Mars) is the smallest satellite.
• Titan has an atmosphere like Earth.

Asteroids

• Asteroids are small planetary bodies that revolve around the Sun and are found between the orbits of Mars and Jupiter.

The Earth's Interior

• The Earth's interior is composed of three major layers: the crust, the mantle, and the core.
• Eduard Suess explained the interior of the Earth based on chemical composition as SIAL, SIMA, and NIFE.

Rotation and Revolution of the Earth

• The Earth spins on its imaginary axis from West to East in one day, resulting in day and night, and tides.
• The Earth's motion in an elliptical orbit around the Sun in one year results in changes of seasons.

Statistics Data of the Earth

• Longitudes (Meridians) are a series of semicircles that run from pole to pole, passing through the equator.
• The Prime Meridian passes through Greenwich near London, dividing the Earth into Eastern and Western hemispheres.
• The International Date Line (IDL) is the longitude where the date changes by exactly one day when it is crossed.