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SCIENCE : ASTRONOMY
A Sensitive Probe
Meanwhile, ISRO,
which had been studying upper atmospheric phenomenon since the 1960s,
had developed state-of-the-art equipment to conduct extremely sensitive
probes. Late last year, Narlikar along with Wickramasinghe approached
ISRO Chairman K. Kasturirangan to help them out. The cost was pegged around
Rs 60 lakh but Kasturirangan decided it was worth the effort. His reason:
"We are addressing a fundamental question where even a 'no' can profoundly
influence our understanding of how life began." An ISRO team headed
by senior scientist P. Rajaratnam then went about building probes to overcome
the earlier lacuna that NASA experienced.
To ensure that samples of air were collected
in the most stringently aseptic conditions, the ISRO team precision-machined
vacuum flasks for collecting the samples. These were then autoclaved at
temperatures of 140 degrees Celsius. Cryogenic or supercooled fluids were
used to operate the pumps that sucked the air when the probes were opened.
The gizmo was loaded onto a giant balloon used to explore the earth's
atmosphere. Telecommands were used to automatically open the probes to
collect samples of air in stratosphere. Duplicate samples were deliberately
taken so that two independent teams could analyse their content. When
the payload was recovered from Kolhapur 400 km away, the samples containing
air were then passed through superfine filters that would trap microbe-sized
particles if they were present.
These filters were then sent for separate analysis
to the School of Biological Sciences at Cardiff University and the Centre
for Cellular and Microbiology (CCMB) in Hyderabad. While the CCMB's preliminary
findings showed up nothing, the team at Cardiff struck the mother lode.
Microbiologist Lloyd David, using a technique developed for mineral water
companies to detect bacteria, came up with some startling evidence. In
this technique the filters are coated with a special fluoreoscent dye
that when subjected to ultraviolet light would illuminate any viable living
cells. These can then be seen using a microscope. Lloyd was stunned to
see large clusters of fluoreoscent spots and says, "There was little
doubt that there were clumps with sizes appropriate to bacteria at all
heights from 25 to 41 km."
Excitedly Lloyd informed Wickramasinghe whose
laboratory is almost next door at Cardiff. Even Wickramasinghe was taken
by surprise when he saw the profusion of living cells in Lloyd's analysis.
No doubt, laboratory studies had shown micro-organisms could survive in
such hostile environments as Antarctica. But as Wickramasinghe pointed
out: "It was not just isolated cells we had but a huge mountain of
them. It provided unequivocal proof that there are living cells in the
very high stratosphere." When Wickramasinghe and Narlikar examined
it more closely, they came up with even more striking conclusions. If
the bacteria originated from earth then there should be a natural decline
as one probed higher in the atmosphere. Gravity too would ensure that
even if there was a major event like a tornado that kicked up dust from
the earth to the sky it would soon settle down. There was a possibility
of contamination from aircraft flying at the height of 16 km. But at 40
km the chance of bacteria coming from terrestrial sources is remote.
Their slides, however, showed that there was
no natural decrease in the density of particles. They calculated that
for every litre of air, the earth was being bombarded by a third of a
tonne of biomaterial from outerspace. It was consistent with their basic
premise that if life was brought to earth by comets some four billion
years ago, the process of cometary injection of living material should
have continued to the present day and, therefore, should be testable.
It was known that hundreds of tonnes of cometary material enter the earth's
upper atmosphere daily. But the idea of panspermia (or the concept that
life on earth was fertilised from interstellar space) involves cometary
bombardment containing biological material. Now for the first time they
have clear proof of such a phenomenon.
Not all the team members were convinced that
they should make their initial findings public so soon without a more
detailed verification. Pushpa Bhargava, former director of the CCMB and
one of the collaborators in the study, believed it was too premature to
"jump to such big conclusions". Since the CCMB team, which he
was closely associated with, had found nothing in their samples, he wanted
the Cardiff group to share the technique so that the results could be
replicated. He was also keen that the more definitive DNA sequencing could
be done and told Wickramasinghe: "No serious molecular biologist
would accept that we are dealing with live organisms unless we show that
there is DNA present."
The Cardiff team is miffed with the CCMB's line
of questioning. Lloyd points out that he is a scientist of 20 years' standing
and the technique he used to identify living cells were definitive. He
says, "I stand by them" but admits that "that our findings
are only the first step". The Cardiff team has started work on the
DNA sequencing and it could take several months before they could complete
it. But Wickramasinghe reasoned: "We have a saying that if it looks
like a duck, walks like a duck and quacks like a duck then it must be
a duck. Why doubt it?" So Wickramasinghe went ahead and presented
the paper at San Diego, even dropping the names of the CCMB team. Bhargava
now charges Wickramasinghe with behaving in an "unscientific, unethical
and immoral" manner.
That move has created bad blood among the team
members and it threatens to undermine the credibility of their findings.
Bhargava does have a point though. The team may have been hasty in making
its results public when a few months' time would have given them the chance
to do the experiments needed to firmly establish their findings. There
are critical questions yet to be answered: Do these bacteria have any
resemblance to those found on earth? Can these experiments be replicated
to show that they are not the result of some extraordinary phenomenon
occurring over the Hyderabad skies? Are their findings sufficient to establish
the extra-terrestrial origin of life?
Certainly the team is onto something big. For
if they are able to prove that life does have a cosmic origin, then major
biological concepts including the mechanistic theory of the origin of
life would have to undergo radical changes. Darwin's theory of natural
selection will now have to take into account the assistance of genes from
inter-stellar space. Extra-terrestrial bacteria may also have introduced
such horrific diseases as the bubonic plague and even aids.
More than anything else the discovery once again
leaves wide open the fundamental questions of how and where life began.
As Wickramasinghe says, "We may all be truly the children of space,
the offspring of a higher cosmic system." It is an intriguing possibility.
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