Daily News Analysis

Planetary Conjunction

12th July, 2021 Science and Technology


  • Mars, Venus, Moon are set to align on July 12-13.



  • Both Mars and Venus will appear in the western horizon under clear weather conditions just after sunset.
  • Before that, the moon will pass closest to the two planets.
  • This unique phenomenon is part of planetary conjunction. Such conjunction takes place when two planets appear to have come closer, while in reality they remain far away.
  • Mars and Venus are likely to be 0.5 degrees apart as observed from Earth, though they are actually further apart.
  • The planetary alignment will be observable only from Earth.


Types of Conjunctions

  • As seen from a planet that is superior, if an inferior planet is on the opposite side of the Sun, it is in superior conjunction with the Sun.
  • An inferior conjunction occurs when the two planets lie in a line on the same side of the Sun.
  • In an inferior conjunction, the superior planet is "in opposition" to the Sun as seen from the inferior planet.
  • A triple conjunction is an astronomical event where two planets or a planet and a star meet each other three times in a short period, either in opposition or at the time of inferior conjunction, if an inferior planet is involved.
  • The lining-up of three planets is a particular case of


What are Superior and Inferior Planets?

·        In the Solar System, a planet is said to be inferior or interior with respect to another planet if its orbit lies inside the other planet's orbit around the Sun.

·        In this situation, the latter planet is said to be superior to the former.

·        In the reference frame of the Earth, in which the terms were originally used, the inferior planets are Mercury and Venus, while the superior planets are MarsJupiterSaturnUranus and Neptune

·        Dwarf planets like Ceres or Pluto and most asteroids are 'superior' in the sense that they almost all orbit outside the orbit of Earth.