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Mars Opposition 2020

Mars Opposition 2020

Context:

According to NASA, this year Mars’ closest approach to Earth was on October 6, the opposition will happen on October 13, which will give the planet its “biggest, apparent size of the 2020s”.

The opposition:

  • It is the event when the sun, Earth, and an outer planet are lined up, with the Earth in the middle.
  • The event of Opposition, in the case of Mars, takes place every two years and two months (26 months).
    • During this event, Mars outshines Jupiter and becomes the third brightest object (moon and Venus are the first two) in the night sky.
  • The time of opposition is the point when the outer planet is typically also at its closest distance to the Earth for a given year.
  • An opposition can occur anywhere along Mars’ orbit, but when it happens when the planet is also closest to the sun, it is also particularly close to the Earth.
  • As per NASA, from an individual’s perspective on the Earth, Mars rises in the east and after staying up all night, it sets in the west just as the sun rises in the east and sets in the west.
  • The Sun and Mars appear to be on the opposite sides of the sky and that is why Mars is said to be in “opposition” because of the perspective on the Earth

Occurrence of Opposition:

  • Earth and Mars orbit the sun at different distances (Mars is farther apart from the sun than Earth and therefore takes longer to complete one lap around the sun).
  • The event of opposition can happen only for planets that are farther away from the sun than the Earth.
  • In case of opposition, Mars and Sun are on directly opposite sides of the Earth i.e. the Earth, sun, and Mars all lie in a straight line, with the Earth in the middle.
  • As per NASA, Mars made its closest approach to Earth in 2003 in nearly 60,000 years and it won’t be that close to the planet until 2287 because the orbits of Earth and Mars are not perfectly circular and their shapes can change slightly because of gravitational tugging by other planets.

Why opposition doesn’t always mean the closest point to Earth?

  • Mars' orbit is more elliptical than Earth's which causes the difference between perihelion and aphelion to be greater.
  • The gravity of Jupiter tugs on Mars and causes its orbit to be a bit off-kilter compared with Earth.
  • The orbital quirks can lead to Mars sometimes be closest before opposition, and therefore before it appears brightest.

Source: Indian Express