On July 30-31, 2018, Mars and Earth are closer than since their historically close approach in 2003. Mars was closer in 2003 than in some 60,000 years, and it’s now only slightly farther from Earth now than then. It’s about 35.78 million miles (57.59 million km) away at its closest on July 31 at 08:00 UTC. That time places Mars’ closest approach before sunrise on July 31 for North American time zones – and on July 30 at 10 p.m. Hawaiian Time.
Mars at opposition
“Mars orbits the Sun at a greater distance than Earth. As the distance increases, the orbital period also increases. While Earth takes a little more than 365 days to go round the Sun, Mars takes 687 days. Due to the difference of the orbital speed and orbital period, every 26 months or so Earth passes between Mars and the Sun, bringing Mars and Sun on exactly opposite sides of the Earth. This is called Mars at Opposition,” explains Dr. Debiprosad Duari, Director, Research & Academic, M. P. Birla Institute of Fundamental Research, Kolkata. At opposition Mars will be near its closest point to Earth.This year Mars was at its opposition on July 27. Since it is quite close from that time, it will appear very bright and will be visible roughly after sunset and will remain in the sky till sunrise.
The next opposition of Mars will be on October 6, 2020 but it will be a little further away — 61.76 million km — and will be relatively smaller and less bright than on July 31, 2018.
Will it appear as big as the Moon?
At its closest approach this time Mars will be only 24.3 arc seconds across and nowhere close to the size of the moon, which is 75 times bigger in diameter as it appears. (1 arc second is 1/60 of arc minute and 1 arc minute is 1/60 of a degree in the sky. For reference, the diameter of Moon is about 31 minutes of arc).
How do I know which is Mars?
Just after the sunset, look to the east-southeast horizon. Mars will appear 1.8 times brighter than the biggest planet of the solar system, Jupiter.
Where to watch Mars closest to Earth in India
The best place to watch Mars in closest position to Earth is in the Southern Hemisphere, which means India is not in the best location for this celestial phenomenon. However, visibility will not be too bad as it is estimated that the planet will be easily visible from all parts of India, just not as well as it would be from Australia, South Africa or countries in South America. You will need a telescope with a large lens (6- to 8-inch in size) to be able to see the planet, and even then the clouds may obstruct your view.
If you want to watch online Mars closest to Earth, you can also view the phenomenon on a YouTube live stream. NASA’s Griffith Observatory is hosting a live stream of the event tomorrow, which you can start by hitting the play button below: