Red Planet Day
Red Planet Day is November 28th every year. It commemorates the launch of the Spacecraft Mariner 4 on November 28,1964. (The 228 day mission of Mariner 4 brought the spacecraft within 6,118 miles of Mars on July 14, 1965.)
The planet Mars is referred to as the 'Red Planet' because it appears red in color. Red Planet Day honors our celestial neighbor, the fourth planet in the solar system. It is the first of the 'superior' planets, being further from the Sun than the Earth. Like Earth, Venus, and Mercury, Mars is a rocky planet, but is relatively small, being between Mercury and Venus in size.
On Red Planet Day, take a few minutes to look upwards into the sky, and gaze at our neighbor. Hopefully, you will have a cloudless night sky for viewing. You can also recognize this day by reading up about Mars, and viewing pictures of it.
Mars is the fourth planet from the Sun and the second smallest planet in the Solar System. Named after the Roman god of war, it is often described as the 'Red Planet', as the iron oxide prevalent on its surface gives it a 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 volcanoes, valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the highest known mountain within the Solar System, and of Valles Marineris, one of the largest canyons. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars 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.
Until the first successful flyby of Mars occurred in 1965 by Mariner 4, many speculated about the presence of liquid water on the planet's surface. This was based on observed periodic variations in light and dark patches, particularly in the polar latitudes, which appeared to be seas and continents; long, dark striations were interpreted by some as irrigation channels for liquid water. These straight line features were later explained as optical illusions, though geological evidence gathered by unmanned missions suggest that Mars once had large-scale water coverage on its surface. In 2005, radar data revealed the presence of large quantities of water ice at the poles and at mid-latitudes. The Mars rover Spirit sampled chemical compounds containing water molecules in March 2007. The Phoenix lander directly sampled water ice in shallow Martian soil on July 31, 2008.
Mars is currently host to five functioning spacecraft: three in orbit—the Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter; and two on the surface—Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity. Defunct spacecraft on the surface include MER-A Spirit, and several other inert landers and rovers, both successful and unsuccessful, such as the Phoenix lander, which completed its mission in 2008. Observations by NASA's now-defunct Mars Global Surveyor show evidence that parts of the southern polar ice cap have been receding. Observations by the Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on Mars.
Mars can easily be seen from Earth with the naked eye. Its apparent magnitude reaches -3.0, which is only surpassed by Jupiter, Venus, the Moon, and the Sun. Optical ground-based telescopes are typically limited to resolving features about 300 km (186 miles) across when Earth and Mars are closest, because of Earth's atmosphere.
Basic Facts about Mars
Fourth Planet from the Sun
Mars gets it's name from the Greek word 'Ares', the God of War
Often visible to the naked eye
Distance from the Sun: average 136,764,000 miles
Rotation around the Sun: 687 days
Rotation period: 1.026 Earth days
Gravity: 1/3 of Earth
Size: 7th largest planet, about 1/10th the mass of Earth
Temperature range(F): -207 to +81 degrees