On Monday evening, May 30, Mars will approach as close as possible to Earth, starting on October 5, 2005.
Last Sunday morning (May 22), Mars reached opposition with the Sun, which means that the Red Planet, the Earth and the Sun were lined up in a straight line. But it is worth noting that this is not the closest passage of Mars to Earth.
On Monday evening at 21:35 GMT, Mars will be as close to Earth as possible from October 5, 2005: 0.50321377 astronomical units, or 46, 762, 695 miles (75, 279, 709 kilometers). One astronomical unit is the average distance from the Earth to the Sun, which is 93 million miles or 150 million km.
Opposition and the nearest passage take place on different days, since the orbit of Mars has the shape of an ellipse.
The image shows how Mars will look through the Hubble telescope at the time of closest approach. Here you can see the landing site of the NASA Opportunity rover in the eastern part of the Red Planet and the highest Solar System Olympus volcano in the western. The Mariner Valley, which is larger and deeper than the Grand Canyon near the Earth, is located in the center, and the dark Acidalian Plain is high in the north, near the small north polar cap. What can you see with an ordinary amateur telescope? I'm afraid very little. You can see a hint of a polar cap and a few blackouts. If conditions are perfect, amateur astronomers will also notice the crater Olympus, but it’s problematic to see the powerful valley of Mariner.
If you observe Mars for a few hours, you will be able to see how the dark areas move around the disk, as Mars rotates a little slower than the Earth, and makes a full turn in 24 hours 37 minutes and 23 seconds.
Sometimes it seems that the dark areas themselves move and change their shape. This is usually caused by giant dust storms that swept across the surface of Mars. Recently, British amateur astronomer Damian Peach reworked a number of old images of Mars taken in the 1930s, 1940s and 1950s using modern image processing techniques. Pich's work showed amazing details that are not visible on the original images. It is believed that these changes are the result of the quicksand of Mars over the decades.