Around 15 to 17 years old, Earth will be closest to Mars in the near helicopter. The last time this happened was August 27, 2003, at a distance of 55.7 million km from the two planets.
On October 6, Mars would be closest to Earth, next to perihelion (the point closest to the Sun). It wasn’t until 2035 that the two new planets were so close again.
Earth orbits in an almost circular orbit, while Mars is elliptical. If our planet takes 365 days to complete a turn, it takes 687 days for Mars. 780 days later, Earth and Mars will intersect. In addition, they both revolve around the Sun in the same direction but with different speeds and distances.
Earth is closest to Mars every two years during the rotation of the two planets. But it is only when Earth approaches or coincides with Mars’ near annihilation point that we can see that this planet is at its maximum.
The spacecraft carrying the self-propelled Perseverance robot successfully launched in late July is expected to reach Mars in February 2021. The close proximity of the two planets also provides ideal launch conditions that only appear every few years, helping to reduce fuel consumption.
The orbits of the planets in the solar system are almost circular. In it, the orbit of Mercury and Mars is more elliptical than the other planets. At the parietal point, Mars is 0.38 astronomical units from Earth. At aphelion, this star is 0.66 astronomical units from Earth, almost twice as large.
Seen from Earth, the angular (apparent) diameter of Mars changes the most during the year compared to other planets in the solar system. When Mars has the greatest apparent angle, it could be larger than Saturn and roughly the size of Jupiter.
Unlike Earth, the seasons of Mars are affected by an almost elliptical orbit rather than an axial tilt. Winter comes when the planet is furthest from the sun and the opposite of summer. The two images above taken with Hubble glass from left to right in July and September 1997 show the changing surface of Mars. Visible in September, the planet is warmer, with less ice and cloud covering the surface than in July.
In summer, when the weather is relatively warm, Mars often experiences dust storms. The storm appeared in the summer of 2001 and covered the entire planet.
During this month of October, Mars will shine in the sky at the largest size visible from Earth in two years. So even amateur astronomers can clearly see features of the planet’s surface, such as the polar ice cap.