Quest of humans to find others of their kind is as old as the ascent of man itself. People have travelled across the deserts, scaled mountains and sailed high seas in search of other intelligent beings. This search got extraterrestrial dimension when Italian astronomer Giovanni Schiaparelli looked at Mars through his telescope. What he observed on the surface of Mars were what he called canali in Italian, meaning "channels" or "grooves". These were mistranslated in English as "canals" and interpreted as dug by highly advanced Martians for transportation of water from the polar region to the equatorial zones. The year was 1877.
What was so special about 1877? We will come to that shortly.
By the end of 17th century people had begun to accept that the Sun is the centre of our solar system. Galileo Galilie gave observational evidence and his contemporary Johannes Kepler discovered laws governing planetary motion. The first law of Kepler states that the planets move in elliptical orbits. That is, planets do not go round the sun in circular orbits, but in orbits which are slightly oval.
Also the planet closer to the Sun moves faster than the planet that is further away. As the planets go round the Sun there comes a time when the Sun, the Earth and a planet comes nearly on a straight line. This is called opposition of that planet - the Sun and the planet are in the exactly opposite direction. Obviously at the time of opposition the planets are also close to each other. The date of opposition differs from planet to planet. However, the date of closest approach may differ slightly than the date of opposition, due to the elliptical orbits of the planets.
The closest approach between Earth and Mars occurs every 26 months. But due to their elliptical orbits the closest distance between two planets keeps changing from time to time in a regular manner, in case of Mars and the Earth the distance ranges from about 56 mn km to 100 km over a period of 15 to 17 years.
In 1877 the red planet was 56 mn km from Earth and thus best placed for observations.
Percival Lowell a wealthy American businessman was highly intrigued by the canals on Mars and made study of the planet the career of life. He established an astronomical observatory dedicated for his study of Mars in 1894. And when not observing Mars, Lowell toured the world giving lectures about his observations. (Lowell was also responsible for discovery of Pluto. He funded the search.)
In 1897, ‘Canals on Mars’ also inspired famous science fiction writer H G Wells's work The War of the Worlds, one of the first and the most influential fiction in which extraterrestrial beings, Martians in this case, try to invade mankind. But with better telescopes and observations it became clear that no such life exists on Mars and the canali of Schiaparelli were optical illusions. However, Mars proves to be the most prominent place in the solar system other than the Earth to find signature of life in its most initial form. Search for such signature is one of the main aims of mission to Mars which are planned around the time when the two planets come close to each other.
On April 14, 2014 Earth and Mars will be closest to each other again after the 26 month gap, where in the distance will be about 92 mn kms. But this is not the best closest approach; 2003 saw one of the closest approaches–59 mn km–after about 60,000 years. The planet will be easy to locate and you will also be able to see some features on the Martian surface even through moderate size amateur telescope. At about 7:30 p.m. You will spot two bright stars above the eastern horizon, the one on the left is Arcturus or Swati and to the right is Spica or Chitra. A bit to left of Chitra and above, the crimson planet.
Don’t miss it.