Mars is the fourth planet from the Sun and the second-smallest in the Solar System, after Mercury. Named after the Roman god of war, it is often referred to as the “Red Planet” because of its reddish appearance. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts and polar caps of Earth.
It has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Martian trojan asteroid.
Mars can be seen from Earth with naked eye, as can its reddish coloring at times. Its apparent magnitude reaches −2.94, meaning it can cast shadows and can be easily out shining Venus (magnitude −4.6) at certain times of year from certain locations on Earth’s surface. Mars even appears bright enough to cast shadows momentarily during an extremely rare phenomenon known as a transit opposition when it passes directly between Earth and the Sun while being nearest to us in its orbit. Oppositions occur approximately every 26 months and last for about two weeks each time they occur; during this time Mars’ brightness increases due to reflectance off its disk as viewed from our more distant vantage point along Earth’s orbit around the Sun. The next oppositions will occur on October 13–14, 2032 (estimated magnitude: −2.8) visible in much of Asia including India; May 22–23 2039 (estimated magnitude: −2.7), visible throughout most of North America except for Alaska;and finally on November 1–2 2046 (estimated magnitude: −3), visible over most inhabited areas worldwide except for high northern latitudes such as Canada or Scandinavia.
Mars is one of only five planets visible to unaided human eye, all five being within our Solar System (Mercury, Venus, Mars, Jupiter and Saturn).. The other four planets are also terrestrials like Mars but are significantly larger—Earth being almost 11 times wider across than Mars—and thus brighter when viewed from Earth through binoculars or a telescope despite their greater distance away.. If aliens were observing our solar system from afar they would likely see little difference between these five planets since all would look like small bright dots without any distinguishable features due to their great distance away combined with telescopes not yet powerful enough to magnify objects that far into space with any clarity.. Nevertheless, if said aliens had better technology they might notice some subtle differences in these five points of light that betray important information about each one’s composition and physical properties such as mass or temperature