Evidence of liquid water in comets reveals possible origin of life
July 30, 2009Comets contained vast oceans of liquid water in their interiors during the first million years of their formation, a new study claims.
The watery environment of early comets, together with the vast quantity of organics already discovered in comets, would have provided ideal conditions for primitive bacteria to grow and multiply. So argue Professor Chandra Wickramasinghe and his colleagues at the Cardiff Centre for Astrobiology in a paper published in the International Journal of Astrobiology.
The Cardiff team has calculated the thermal history of comets after they formed from interstellar and interplanetary dust approximately 4.5 billion years ago. The formation of the solar system itself is thought to have been triggered by shock waves that emanated from the explosion of a nearby supernova. The supernova injected radioactive material such as Aluminium-26 into the primordial solar system and some became incorporated in the comets. Professor Chandra Wickramasinghe together with Drs Janaki Wickramasinghe and Max Wallis claim that the heat emitted from radioactivity warms initially frozen material of comets to produce subsurface oceans that persist in a liquid condition for a million years.
Professor Wickramasinghe said: "These calculations, which are more exhaustive than any done before, leaves little doubt that a large fraction of the 100 billion comets in our solar system did indeed have liquid interiors in the past.
Comets in recent times could also liquefy just below their surfaces as they approach the inner solar system in their orbits. Evidence of recent melting has been discovered in recent pictures of comet Tempel 1 taken by the "Deep Impact" probe in 2005."
The existence of liquid water in comets gives added support for a possible connection between life on Earth and comets. The theory, known as cometary panspermia, pioneered by Chandra Wickramasinghe and the late Sir Fred Hoyle argues the case that life was introduced to Earth by comets.
Source: Cardiff University (news : web)
Aug 14, 2007 |
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The water is liquid when the comet is close to the Sun, but it is ice when the comet moves to the outer region of the solar system.
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I have not read description of the accretion process that indicates the phase shifts that may occur for matter involved in gradually more violent collisions of higher mass objects in the same orbit, but have read about the formation of Earth's core in isolation from the accretion process that created it. If Iron with a mix of mineral impurities can turn to liquid, (and then plasma), due to the pressure induced by the mass (and density) of material that sits on the surface of the 'collection', then is it possible that other matter is suspended in not solid form within other planet(oid)s?
How much pressure would be required to force ice to become liquid?
Water is 'tricky'. Scientists are still being surprised by the phase changes water presents in different circumstances and conditions. We (all?) know that water expands when it is frozen, but not everyone understands that large masses of water at significant sub-zero temperatures flow as liquid in the polar regions of Earth. In laboratory conditions, water has remained liquid at above boiling point, and has 're-liquefied' at way below zero.
We know that life on Earth requires liquid water. But in space, does life need liquid water at Earth temperatures? Even on Earth, we have found life that 'reanimates' when the ice suspending it melts (not quite cryogenic freezing, but similar). We (all?) have seen the fascinating movies from robots near the Ocean floor filming thermal vents of super-heated liquid water with many mineral impurities that we would consider lethally poisonous, being 'enjoyed' by many diverse forms of life %u2013 some being distinct adaptations of animals we are familiar with.
The question is, could similar life exist in objects with liquid water at their core, and would that life survive on star light in the absence of sunlight?
At the Oort Cloud distance from the Sun, the Sun appears as the brightest star in the sky, but not the significant heat and light source that it is for us. The temperatures in space at that distant are unimaginably low (as far was we know), but that should not condition our thinking about the objects that exist in the Oort Cloud which got its name from the discoverer and the fact that those objects are primarily ice.
We know that conditions on the inside of a planetoid are significantly different from those of the surface so, it is possible that large ice based planetoids could produce enough internal pressure to liquefy their cores, as our iron based planet has?
Last question, (answers are desired): how can we detect, locate, observe, analyse and see inside of a Jupiter sized ice block somewhere between the Oort Cloud and the Sun?
I would use a high-powered Laser, perhaps located on the lunar surface, which is mirrored to light up small quadrants of the Oort Cloud, and then observe the reflections using Hubble. Ideally, the laser would be capable of transmitting several different wavelengths.
This was just an idea...I'm sure there are other possible ways to do it.