All eight planets in our solar system (or nine, if you still include Pluto) revolve around the sun in concentric planetary orbits with the sun at the center. Due to their distances from the life-giving star, each planet takes a different time to orbit the sun.
Mercury, for example, doesn’t have as far to travel as Earth, and Earth doesn’t have as far to travel as Saturn. None of the planets travels the distance that Neptune must travel.
What is planetary opposition?
In astronomy, opposition means that a planet is “opposite the sun”. But planetary opposition it’s when a planet’s orbit takes it between the sun and another planet. The Planetary Society defines opposition as “when the planet is opposed to the position of the sun”. This means that a planet in opposition is 180 degrees from the sun in the sky.
Because the sun sets in the west, during planetary opposition, astronomers would look east to see the opposite planet as it rises in the night sky. (Isn’t that cool?) Planetary oppositions occur about once a year between Earth and the planets outside of its orbit – Jupiter, Saturn, Uranus and Neptune.
Earth and its nearest neighbor Mars have orbital speeds so similar that Earth surveys Mars every 27 months for planetary opposition. And, because Mercury and Venus are located between the sun and Earth’s orbit, Earth will never be in planetary opposition to them.
When and how to see a planet in opposition
Why is planetary opposition important? Planetary opposition gives astronomers and other stargazers the best views of our planetary neighbors. Planets often appear larger, brighter, and better placed in the sky during opposition. You can even see some planets with the naked eye, but you can see them better with magnification from binoculars or telescopes, especially if you can see them in an area with less light pollution.
Want to see planetary opposition? Check out these celestial events that will occur during the rest of the calendar year 2022.
- Neptune in opposition: September 16, 2022, 9:03 p.m. GMT (5:03 p.m. EDT). You will need powerful binoculars or a telescope.
- Jupiter in opposition: September 26, 2022, 6:03 p.m. GMT (2:03 p.m. EDT). The planet should be large and bright in the sky, but you’ll see it best with binoculars or a telescope.
- Uranus in opposition: November 9, 2022, 8:41 a.m. GMT (3:41 a.m. EST). Uranus should be visible to the naked eye, but binoculars will help.
- march in opposition: December 8, 2022: 4:24 a.m. GMT (12:24 a.m. EST). Mars will be obvious to the naked eye, but take the opportunity to observe it through binoculars or a telescope, as this will be the last time you will see Mars in opposition until 2025.