9781916296442_

A concise history of Mars from the earliest pre-telescopic observations to the robotic probes of the Space Age. This 12,000 word eBook Short Read describes how our views of the Red Planet have changed over the last two centuries - from the home of beings possibly more advanced than ourselves to a lifeless world as desolate as the Moon, and to the modern view of a world where water was once abundant and life might possibly still exist.

Did you know?

*A Google search on Mars brings up more hits than any other planet in the Solar System, apart from Earth.

*The shield volcano Olympus Mons is 21,229 m (69,219 ft) high; it is 2 ½ times higher than Mount Everest above sea level and more than twice the base-to-tip height of Mauna Kea. Its claim to be the Solar System's tallest mountain has been challenged by the central peak of the impact crater Rheasilvia on the asteroid Vesta, which rises 20,000 – 25,000 m (65,000 – 82,000 ft) from the base of the crater. However, there is a degree of uncertainty in the measurement of Rheasilvia. Olympus Mons is 600 km (370 miles) in diameter, comparable in size to the state of New Mexico.

*Mars is the only visibly red planet in the night sky, but the first-magnitude stars Arcturus, Betelgeuse, and Antares also have a clear orange-red hue. Indeed, Antares means 'rival to Ares', i.e., Mars.

*Mars and Earth can approach one another to within 56 million km (35 million miles), but this is further than the minimum Earth-Venus distance of 40 million km (25 million miles).

*Mars is only the third closest planet to Earth. Although Mercury never comes closer than 92 million km (57 million miles), its average distance from Earth is less than that of Mars.

*Mars has the most eccentric orbit of any of the major planets, apart from Mercury. Consequently, its distance at opposition varies from 56 million kilometres (35 million miles) when at or close to perihelion to 101 million km (64 million miles) when at or close to aphelion. No other planet shows such a variation in opposition distance. The apparent magnitude at opposition varies from -2.9 to -1.2, meaning that Mars is almost five times brighter at a perihelion opposition. Favourable oppositions occur in groups of two or three every 15 or 17 years.

*On 27 August 2003 at 09:51 GMT, Earth and Mars were 55,758,006 km (34,646,418 miles) apart, centre to centre. This was the closest approach for almost 60,000 years. The event was well publicised, and there was a popular misconception that Mars would appear comparable in size to the Moon in the night sky. In reality, it was only slightly brighter than it had appeared when at opposition in 1988.

*Mars can show an obvious gibbous phase (85% full) when viewed through a good amateur telescope. Although the other superior planets can also exhibit a gibbous phase, it is undetectable except through the most powerful telescopes. The maximum phases of Jupiter and Saturn are 99.1% and 99.7% full, respectively.

*The chances of anything coming from Mars: Scientists have not had to wait for a sample return mission to Mars. Rocks blasted into space by asteroid impacts have reached Earth from Mars, the Moon, and Vesta. A Martian meteorite that landed in fragments around the Egyptian village of El Nakhla is said to have killed a dog. However, hard evidence is lacking, and the story is probably apocryphal.

*Mars has been visited by more space probes (28) than any Solar System object, apart from the Moon. Only 22 were completely successful; six orbiter/landers reached Mars successfully, but the lander subsequently failed. Two further probes have performed a successful swing-by of Mars en route to other destinations, though they did return useful images and data in the process. Currently, there are 12 orbiters, rovers, and landers returning data from Mars.

Mars: the Red Planet from Pre-Telescopic Observations to Perseverance

Comentarios