ONCE Uranus had been discovered (1781), and Neptune had been found (1846), it was natural for astronomers to wonder whether it was the end of it all. Was another one lurking beyond Neptune? Was the Solar System a lot larger than what our ancestors thought?

That such a body, planet or whatever else, was very difficult to locate was on account of the fact that anything beyond Neptune would be far more difficult to find than the proverbial needle in the haystack. It would be far dimmer, and if it happens to be smaller than Neptune, the harder it would be to run into. Also, it would be hidden among a large number of stars as bright as itself, or even brighter.

With painfully slow movement among stars, it would be all the more hard to find. The bigger the telescope, the more numerous the stars that would appear in its field of view. Bigger telescopes therefore made it easy, as well as difficult at the same time, to find what they were looking for.

With the passage of time, hope continuously dwindled. In the first place, no one knew where exactly it could be for its gravity did not cause discernible disturbance in the track of Neptune. As you are aware, scientists do not respect privacy, of planets or whatever else. They must pry into the affairs to get to the bottom of the causes that dictate behaviour of things. Dozens at first, then hundreds when things began to heat up, put their heads together. The greatest clue would emerge from Neptune's motion in its orbit around the Sun.

It was soon discovered that a tiny amount of discrepancy in Uranus’ orbit stood yet unaccounted for, which was not the doing of Neptune (for that had been accounted for) but of some other body. Just imagine, a tiny celestial body nudging at a giant, and to good effect!

At this point in time, one astronomer stands taller than the rest. The American, Percival Lowell (1855-1916), working at Lowell Observatory in Arizona, gave his life to the search. Lowell threw himself into the task with such eagerness and energy that it literally broke his back. Working night and day he employed endless photography over the task. He wore himself out: lost a lot of weight, all his peace of mind and soon died of stroke. Few scientists had dedicated themselves to that extent. Still, he never found the elusive planet. Nevertheless, he had done enough work for others to carry on their task. Although there are a few martyrs to science, there are many more who lived and suffered.

Many other astronomers followed suit. Next to achieve prominence was Clyde William Tombaugh (1906-1997). The grand old man of science also toiled at Lowell Observatory. Tombaugh had the advantage of bigger telescopes and better photographic equipment. Thousands of star plates, and tens of thousands of stars later, the fruit was at long last delivered. Can you imagine the task that Tombaugh studied star plates carrying a whopping 400,000 stars, day in and day out?

Come March 13, 1930, Clyde Tombaugh entered history books to be interred therein for all times to come. The new planet was at long last found. It was instantly suggested that the planet be named “Lowell after the man who gave his life to the search. The date was also the 75th birth anniversary of Percival Lowell. The name was considered and not adopted. Instead, Pluto was taken for the reason that it is the god of the underworld, crime and what not. Lurking stealthily in some nook and cranny, hiding from prying eyes in some dark and dingy alley. Also, the first two initials: P. L. were the initials of Percival Lowell.

So, not just enough ‘honour’ was paid to a mythological Greek god, thus also justifying the tedious and historical search launched for the elusive planet, but also to a great astronomer.

Pluto is a tiny, but significant planet. Its average distance from the Sun is 5,900,000,000km, and the orbital time is 247.7 years, which means that we humans would have to wait for nearly four lifetimes for Pluto to go around the Sun just once. The one very interesting point that cannot escape our attention ever is the fact that sometime in the course of its orbit, Pluto is the last planet in the Solar System, at other times Pluto is the eighth planet, and the honour of being the last planet instead belongs to Neptune. It is because of the eccentricity in its orbit which pushes it inward for a while. Although their paths cross, they will never crash into one another, rest assured! There is actually no point of intersection between them. The route on which they move, one planet is far above the other. Where the two orbits cross, they are separated by a distance of 1,400,000,000km. The actual closest distance between the two is 2,500,000,000km. For about 10 per cent of the time, Neptune is the outermost planet, for the remaining 90 per cent of the time it is Pluto which is the last planet out.

Pluto has just one moon, named Charon. The diameters of the two bodies are 3,000km and 1200km respectively. By any reckoning, Pluto is a tiny planet; a sort of misfit in the vicinity of great gas giants.

Whatever has been stated by way of interesting information about the Sun or planets is not complete information; it is not even enough. Purposely. The idea was to infuse into you the spirit of enquiry, to fire you up, to turn you into young observers of the heavens and see for yourself how things move in the skies, if at all they move; to help you fall in love with the star-studded sky with all those wonderful actors as they play out their assigned roles. Go ahead and fall in love! Like I did on a winter night of the early 1970s as a young unemployed person. Love at first sight!

There is much more that remains. The birth of the universe, creation of early galaxies, types of stars, binaries, stars themselves, planets have all been discussed. Yet we have a long way to go.

Next we want to discuss a blue/green object that hangs majestically in the sky, Earth. The turquoise ball that is unique among all: it has life. We all know it, but what we want to know for ourselves is: why is it so, whatever is. There are many wonderful things to be discovered.