Earth: Our Place in the Universe

Earth: Our Place in the Universe

Overview of the Earth in Space

  • The Earth is the third planet from the Sun in our solar system.
  • It is a part of Milky Way galaxy which comprises billions of other stars.
  • The Earth spins on its axis, a transparent line around which it rotates. This causes day and night.
  • The Earth’s orbit- the path it takes around the Sun, is slightly elliptical or oval shaped.

The Solar System

  • The solar system is made up of the Sun and everything that orbits around it including planets, moons, asteroids, comets, and meteoroids.
  • The Sun is the centre of the solar system and its gravity keeps all the planets in their orbits.
  • The planets in order from closest to the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
  • There are three classifications of planets: rocky planets, gas giants and ice giants. Earth is a rocky planet.

Characteristics of Earth

  • Earth is the only known planet in the universe to support life. This is mainly due to the presence of water and a suitable atmosphere.
  • Earth has a diversified climate and regions of land (continents) and vast expanses of water (oceans).
  • It is surrounded by an atmosphere composed mainly of nitrogen and oxygen.
  • The magnetic field of the Earth protects it from the harmful solar radiation.

Earth’s Moon

  • The moon is Earth’s only natural satellite.
  • It orbits around the Earth and causes the earth’s tides due to its gravitational pull.
  • The phases of the moon seen from Earth are caused by the moon’s orbit around the Earth.

Our Galaxy- The Milky Way

  • The Milky Way is a spiral galaxy containing billions of stars, gas, dust, and dark matter.
  • Our solar system, including Earth, is located on one of the outer arms of this galaxy.
  • The galactic centre of the Milky Way, containing a supermassive black hole called Sagittarius A*, is thousands of light years away from the Earth.

Universe

  • The universe encompasses everything that exists - galaxies, intergalactic spaces, matter, energy, and even time.
  • Cosmology is the scientific study of the origin, evolution, and eventual fate of the universe.
  • There are hypotheses like the Big Bang Theory explaining the creation of the universe.
  • The Hubble Space Telescope and space missions aid in the study and exploration of universe.