Download Though Pluto may no longer find a place in science

Though Pluto may no longer find a place in science textbooks as the ninth planet in our solar system
— scientists have shrunk the number of planets to eight — it will surely be one of the most hotly
debated and studied objects in the years to come.
If 1930 marked the year when the 22-year-old Clyde Tombaugh discovered Pluto, August 24, 2006,
saw the International Astronomical Union stripping it of its status as a planet. Incidentally, the same
international body recognised it as a planet in 1930.
The controversy
But what in the first place prompted scientists to demote Pluto? The whole controversy started three
years ago with the discovery of Xena by Michael Brown of the California Institute of Technology.
"Had Xena's mass [and hence the lack of nearly round shape] and size been smaller, there would
have been no problems," said Siraj Hasan, Director of the Bangalore based Indian Institute of
Astrophysics (IIAP). Dr. Hasan represented India at the IAU meeting in Prague.
That was not to be. "If Pluto can be a planet then why not Xena," he said about the controversy.
One possibility was to enlarge the definition to include other objects including Xena. If that were so,
there would have been 12 and not nine planets.
And the possibility of more objects being found that would meet the criteria to be designated as
planets is real, as the Kuiper Belt that lies beyond Neptune has many such objects; Pluto, like Xena,
is one of the objects found in the Kuiper Belt.
It was precisely this uncertainty that forced IAU to revisit the definition of a planet.
"A panel of eminent planetary scientists was formed by IAU to get a proper perspective to decide
the basis on which objects will be called as planets," Dr. Hasan said. "Finally consensus began to
emerge. Because of the uncertainty in the number of objects that would meet the present criteria
[of a planet], one more stringent criterion was added to the definition."
Pluto, like Xena and other objects, met the first two conditions (orbiting the sun and being nearly
round in shape) but failed to meet the new third criterion — clear the neighbourhood around its
orbit. And Pluto lost out.
Definition changed
"They have just changed the definition [of planet]. It is more of a change in nomenclature," Dr.
Hasan stressed, "not that we got new information about Pluto that made it no longer a planet."
The reclassification does not in any way change whatever is already known about Pluto. Yet, some
astronomers and others have not taken to its demotion kindly.
"I do understand that many feel bad about it [the demotion of Pluto]," Dr. Hasan noted. While
scientists will soon reconcile and see the basis on which Pluto has been called a dwarf planet,
reactions of many laypersons have been more than sentimental. The very basis on which science
works has now come under scrutiny. Many people with whom this correspondent talked had
developed a cynical attitude towards science.
Not dogmatic
Alas, do people realise that science, unlike religion, is not dogmatic and any hypothesis is always
open to scrutiny? "Science progresses by disproving hypotheses," underlined P.M. Bhargava, former
Director of the Hyderabad based Centre for Cellular and Molecular Biology. "And in the method of
science, when we do experiments to test a hypothesis, we design experiments that would disprove
the hypothesis. And only when no further experiments can be done to disprove the hypothesis does
the hypothesis become a fact."
Science has no room for emotions and sentiments as well. "Methods of science are based on facts,
observations, verification and validation," stressed Dr. Hasan.
"Quite often, science progresses due to bold and imaginative hypotheses. The last step of
verification involves subjecting the new hypothesis to further experimental scrutiny," said Dr.
Baldev Raj, Director of Indira Gandhi Centre for Atomic Research, Kalpakkam. "There are many
instances in science, such as discovery of the electron, when experimental observations were done
much later in time; the hypothesis and theories were well accepted as the hypothesis explained the
real life results in a coherent manner."
Unlike other areas, science encourages dissent and differences of opinion. And repeatability (of
experiments, methods, to name a few) is the cornerstone of science. "In science there is no
objective truth," emphasised Dr. Bhargava.
Only the `test of time' can make disproving certain things less likely to happen. As time passes and
more knowledge is gained and no evidence is obtained to disprove a particular fact, the chances of
disproving the fact keep decreasing.
Curiosity and inquisitive nature seen in small children suddenly disappear when they grow up. Ever
wondered why? "In the process of growing up, curiosity and inquisitive nature seen in small children
are somehow discouraged," noted Dr. Raj. "The emphasis in the current education system should
change from memory-based learning to facilitating creativity. And to increase and sustain the
inherent scientific temper in children, we in the society must discourage those beliefs that are not
based on science."
And when scientific temper and inquisitive nature give way to emotions and sentiments, gullibility
rears its head.
Scientific temper
But what in the first place is scientific temper?
"It is a quality of observing the natural phenomenon and attempting a rational explanation based on
existing knowledge or speculating a new explanation to be verified by further experimental and
theoretical understanding," noted Dr. Raj. "Laws of science are universal. Science is an art of
understanding nature."
"When people lack scientific temper or enough patience to understand a phenomenon, they, in
general, resort to calling it a miracle," said Dr. Raj.
How else would it be possible to explain the mass hysteria and frenzy that was witnessed in 1995
and very recently when the `news' about Lord Ganesha `drinking milk' spread like wild fire. The
fact that some people still believed in milk `miracles' and refused to see the scientific explanations
became clear this time around too.
Or take another recent `miracle' of seawater in Mahim Bay turning `sweet.' Luckily this time, the
mass frenzy witnessed with the milk `miracle' was missing. Whether the scientific explanation
offered or the police prevention of people from drinking the water played spoilsport is debatable.
And `miracles' will continue to happen and people like Ramar Pillai who managed to hoodwink the
scientific community and the lay public for some time, till IIT, Madras called his bluff, will surface
time and again.
"It is totally absurd," said Dr. Bhargava referring to Ramar Pillai's claim. "It defies all laws of
chemistry, laws of conservation of mass and energy and laws of thermodynamics." Yet, Ramar Pillai
was seen as God sent to help India have its own renewable source of `herbal petrol.'
Unlike Ramar Pillai, Madonna, despite her celebrity status, had little luck. An article in Sunday Times
(August 20) recounts Madonna and her husband's aborted efforts to convince the British Nuclear
Fuels (BNFL) scientists on the ways of "neutralising dangerous nuclear waste in Ukraine" using the
`magic' Kabbalah fluid.
Many people who believe in these `miracles' take refugee in the argument that science has not
been able to explain everything seen in today's world, let alone the past.
True. What science has been able to discover and explain is only a fraction. That is no reason for
certain phenomena that can indeed being explained be clubbed with those that science has still not
managed to explain.
That is also a reason why scientific temper is imperative to solve the many mysteries that nature
offers.
Quick Facts about Pluto
Topic
Data
Diameter
2320 km
Density
2.05 g/cm3
Mass
1.290 x 1022 kg
Volume
6.545 x 109 km3
Temperature Range
-240° C to -218° C
Atmosphere
Methane
Winds
Not Measurable
Moons
Three
Average Distance from Sun
5,913,520,000 km
Orbital Period
248 Years, 197 Days, 5.5 Hours
Rotation
6 Days, 9.25 Hours
Tilt
122.52°
Rings
None
Composition
Frozen Methane and Other Ices
Magnetic Field
None
Pluto's origin and identity had long puzzled astronomers. One early hypothesis was that
Pluto was an escaped moon of Neptune, knocked out of orbit by its largest current moon,
Triton. This notion has been heavily criticised because Pluto never comes near Neptune
in its orbit.[98]
Pluto's true place in the Solar System began to reveal itself only in 1992, when
astronomers found a population of small icy objects beyond Neptune that were similar to
Pluto not only in orbit but also in size and composition. This trans-Neptunian population
is believed to be the source of many short-period comets. Astronomers now believe Pluto
to be the largest[note 9] member of the Kuiper belt, a somewhat stable ring of objects
located between 30 and 50 AU from the Sun. Like other Kuiper belt objects (KBOs),
Pluto shares features with comets; for example, the solar wind is gradually blowing
Pluto's surface into space, in the manner of a comet.[99] If Pluto were placed as near to the
Sun as Earth, it would develop a tail, as comets do.[100]
Though Pluto is the largest of the Kuiper belt objects discovered so far, Neptune's moon
Triton, which is slightly larger than Pluto, is similar to it both geologically and
atmospherically, and is believed to be a captured Kuiper belt object.[101] Eris (see below)
is also larger than Pluto but is not strictly considered a member of the Kuiper belt
population. Rather, it is considered a member of a linked population called the scattered
disc.
A large number of Kuiper belt objects, like Pluto, possess a 3:2 orbital resonance with
Neptune. KBOs with this orbital resonance are called "plutinos", after Pluto.[102]
Like other members of the Kuiper belt, Pluto is thought to be a residual planetesimal; a
component of the original protoplanetary disc around the Sun that failed to fully coalesce
into a full-fledged planet. Most astronomers agree that Pluto owes its current position to a
sudden migration undergone by Neptune early in the Solar System's formation. As
Neptune migrated outward, it approached the objects in the proto-Kuiper belt, setting one
in orbit around itself, which became its moon Triton, locking others into resonances and
knocking others into chaotic orbits. The objects in the scattered disc, a dynamically
unstable region beyond the Kuiper belt, are believed to have been placed in their current
positions by interactions with Neptune's migrating resonances.[103] A 2004 computer
model by Alessandro Morbidelli of the Observatoire de la Côte d'Azur in Nice suggested
that the migration of Neptune into the Kuiper belt may have been triggered by the
formation of a 1:2 resonance between Jupiter and Saturn, which created a gravitational
push that propelled both Uranus and Neptune into higher orbits and caused them to
switch places, ultimately doubling Neptune's distance from the Sun. The resultant
expulsion of objects from the proto-Kuiper belt could also explain the Late Heavy
Bombardment 600 million years after the Solar System's formation and the origin of
Jupiter's Trojan asteroids.[104] It is possible that Pluto had a near-circular orbit about 33
AU from the Sun before Neptune's migration perturbed it into a resonant capture.[105] The
Nice model requires that there were about a thousand Pluto-sized bodies in the original
planetesimal disk; these may have included the bodies which became Triton and Eris.[