URBAIN LE VERRIER & NEPTUNE


We see it (the as-yet unseen, probable new planet, Neptune) as Columbus saw America from the coast of Spain. Its movements have been felt, trembling along the far-reaching line of our analysis with a certainty hardly inferior to that of ocular demonstration.”–William Herschel

Human beings have been seeing the sun, the moon and the stars since the dawn of consciousness. When they began to observe these systematically and discern patterns in them they laid the foundation of astronomy, one of the most ancient of the sciences. For many centuries our ancestors had recognized only seven heavenly bodies that moved somewhat differently than the stars: Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn.  These came to be called the planets (Greek word meaning wanderers).  Though some astronomers in India and Alexandria had suspected the sun to be the center of the planetary system, it was the  scientific (Copernican) revolution of the 16th century that changed once and for all times the long held view that the earth is at the center of the universe.  Since then the moon was also recognized as a satellite (companion) of the earth.

For the first time since the dawn of astronomy millennia ago, a new planet was discovered in the 1780s by William Herschel, a German who had settled down in Great Britain.  Herschel  proposed to call it Georgium Sidus (George’s Star) in honor of the British king George III who was then ruling England. Other astronomers proposed names like Minerva, Cybele, Herschel, and even Neptune.  But finally the astronomer Johann Bode’s suggestion that it be called Uranus was adopted.  Uranus is the god of the sky in Greek mythology, married to Gea (the earth).  Saturn was his son and Jupiter his grandson. The French classicist Georges Dumézil had suggested that this name corresponds to the Vedic deity Varuṇa, but this equivalence is now discarded. 

Be that as it may, carefully combing through earlier data, it was found that Uranus had been spotted as a faint speck at least a dozen times before by other telescopic observers who had, however, failed to recognize it as a planet.

The motion of Uranus was studied with great care during the next 50 years. Astronomers detected  certain discrepancies in its regular orbit around the sun. It did not seem to be following the regular smooth elliptical path that a self-respecting planet was expected to take under the Sun’s gravitational pull.

By the 1840s, the peculiar behavior of Uranus was explained by two mathematical astronomers: John Couch Adams of Cambridge, England; and Urbain Le Verrier (born: March 11, 1811), a chemist-turned-astronomer in Paris.  By applying sophisticated mathematics to the orbit-problem, both of them, independently of each other, came to the same conclusion: there must be another planet that it influencing the orbit of Uranus.

Le Verrier had studied a slight deviation in Mercury’s motion: a shift in its closest point to the sun. He surmised another planet much closer to the sun. He even named it Vulcan. Now we know that no such planet exists. The explanation for Mercury’s perihelion was provided by Einstein in his revolutionary theory of Gravitation in the 1910s.

On September 18, 1846, Le Verrier wrote in a letter to the observational astronomer Johann Galle of Berlin: “It is impossible to satisfy the observations of Uranus without introducing the action of a new planet.  It is said that in less than a week of receiving the letter, Galle spotted the planet very close to where Le Verrier had calculated its coordinates to be. As Camille Flammarion put it, Le Verrier “had touched it (Neptune) with the tip[ of his pen.” It is important to stress this point: A remote astronomical body’s existence and position were discovered on paper on the basis of calculations, using the laws of physics and the knowledge of behavior of another planet.  This was a great achievement of the human spirit. And yet, in today’s world there are serious people who question the bases of the scientific enterprise. Of the many embarrassments that humanity must feel, lack of respect for science is a most shameful one.

Different names were suggested for the new planet, such as Janus, Le Verrier, and Oceanus, but finally the name  Neptune was adopted.  This was the name of the Roman god of the sea, corresponding to the Greek Poseidon.

Less than a month after this achievement, William Lassel discovered the large satellite of the newly discovered planet.  This was appropriately named Triton, the son of Poseidon in Greek mythology. For a hundred years this was the only known satellite of Neptune. Today we know Neptune had fourteen satellites. The last one was discovered as recently as in 2013: it is yet to be named.

In 1989, the spaceship Voyager II sent us incredible amounts of fascinating information on distant Neptune and its moons. Its equatorial diameter is almost 50,000 km. Like Saturn, it has rings around it, five to be exact. It is more than 30 times as far from the sun as our own earth is. This makes it path very long, so that takes almost 170 years to go once round the sun. The planet is made up mostly of hydrogen, helium, and methane, all frozen stiff in the extreme cold that reigns is that distance from the sun.

As we rejoice in the discoveries and achievements of our own times pertaining to Neptune and Triton, it is good to remember those whose scientific efforts and curiosity laid the foundations for these.

Has our knowledge of Neptune, its distance and properties served humanity in any way? Perhaps not. But then science, like rhyming poems and subtle philosophy, great  music and grand  art, is not done to serve this or that need or greed of humanity. Rather, it is another expression of the human spirit. Culture and civilization often arise from humanity’s interest in utterly useless things. We actualize a bit of our potential as spiritual creatures by getting to know a little more about the universe of which we are a rare thinking part, just as we degrade ourselves as God’s creation by fighting in His name.

March 11, 2016 

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About Varadaraja V. Raman

Physicist, philosopher, explorer of ideas, bridge-builder, devotee of Modern Science and Enlightenment, respecter of whatever is good and noble in religious traditions as well as in secular humanism,versifier and humorist, public speaker, dreamer of inter-cultural,international,inter-religious peace.
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