Verneshot
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A verneshot is a hypothetical volcanic eruption event which launches an extremely large rock into a sub-orbital trajectory.
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Connection with mass-extinctions
According to the Department of Marine Geodynamics at GeoMar, Kiel (Morgan et al.)Template:Ref, such an event could be triggered by an explosion caused by a mantle plume under a craton in an area of continental rift. Verneshots are one possible cause for extinction level events.
The four major mass extinctions that may have been caused by verneshots are:
- the Frasnian-Fammian extinction event 364 million years ago, killing off 70% of all marine life, linked to the Siljan crater in Sweden and the Pripyat-Dniepr-Donetsk supervolcano in the Ukraine
- the Permian-Triassic extinction event 251 million years ago, killing off 96% of all life on the planet, linked to the Bedout submarine potential impact crater off the coast of Australia and the supervolcano forming the Siberian Traps
- the Triassic-Jurassic extinction event 200 million years ago, killing off 20% of species, linked to the Manicougan crater in Canada and the Central Atlantic Magmatic Province supervolcano off the coast of Sierra Leone
- the Cretaceous-Tertiary extinction event 65 million years ago, killing off 60% of species, linked to the Chicxulub crater in Mexico and the Deccan Traps supervolcano in India
With these four events, massive volcanic activity over thousands of square miles coincides with an impact event. The verneshot theory is that gas seeps up deep underground in an upwelling of magma like the hotspot which formed Hawaii but on a much larger scale. It is trapped beneath impenetrable rock known as a craton (continental plate rock). As pressure builds up, the gas cracks the craton and blasts out at immense velocity. This gas would poison the atmosphere and cause a massive earthquake, enough to level mountain ranges.
The pipe through which the magma and gas had travelled is now empty and collapses. A shockwave at hypersonic velocity would hit the remains of the craton and pulverise them with an explosion equivalent to 120 gigatons of TNT. Twenty billion tons of debris is blasted into the atmosphere while lava fills the hole left behind. The verneshot impactor (the largest lump hurled out) then impacts earth elsewhere. The Chicxulub crater is consistent with such an event with the direction and low angle of impact. However, the velocity would be low compared to an extraterrestrial impactor, so the impactor would mostly survive and although it would be pulverised, it would not be vaporised. Finding rocks from Deccan in Mexico would validate this theory.
What this theory doesn't explain:
- The impact events are associated with layers of extraterrestrial material, such as the iridium of the KT event. This would need to be present in earth's mantle and there is little evidence to support that.
- The impacts are too small; a verneshot would generate an impactor over a hundred miles across, not the ten mile things that bring about mass extinctions. In short, Chicxulub would be larger than the continental United States if caused by a verneshot.
- A verneshot could result in smaller impacts, but there'd be dozens of them. We don't see this. Revision of the scale of the verneshot theory may be necessary.
Smaller scale Verneshots
Less dramatic rock eruptions were documented in 2003 after a 1999 Earthquake in central TaiwanTemplate:Ref. It has also been argued that the Tunguska Event may have been caused by a Verneshot (Tunguska would have been the launchsite not the impactTemplate:Ref).
History
In 1865 Jules Verne's novel From the Earth to the Moon introduced the concept of a ballistic projectile escaping the Earth's gravity, from which Morgan et al. derived the name "Verneshot" in their paper theorizing cratonic gas ejection's connection to extinction events. This was in the projectile-naming tradition of John Hunter, whose 47 m expanding hydrogen gun, SHARP, is only a precursor to the "Jules Verne Launcher" with a 3,500 m barrel length, that was designed in the early 1990sTemplate:Ref for first-stage satellite launch.
Notes
Template:Note (15 January2004), J.P. Morgan, T.J. Reston and C.R. Ranero, "Contemporaneous mass extinctions, continental flood basalts, and ‘impact signals’: are mantle plume-induced lithospheric gas explosions the causal link?", Earth and Planetary Science Letters. (First submitted 17 April2003). For an informal instroduction see Professor Jason Morgan's faculty biography (http://www.geo.cornell.edu/eas/PeoplePlaces/Faculty/JPM/JPM.html) at Cornell University from May 2004: "I became interested in the causes of mass-extinctions, in particular worrying about the 'too-many-coincidences' problem that these periods appear to be associated (if we believe what's published in the mainstream literature) with BOTH extremely rare continental flood basalts and continental rifting, and even rarer 'impact signals' commonly presumed to come from large extraterrestrial bolide impacts. Our recently published Verneshot hypothesis is our best guess on how to explain these coincidences in a self-consistent causal manner."
Template:Note 2004 M. Cirkovic and R.B. Cathcart, "Geo-Engineering Gone Awry: A New Partial Solution of Fermi’s Paradox", Journal of the British Interplanetary Society 57. (See Richard Cathcart's description in The Encyclopedia of Astrobiology, Astronomy, and Spaceflight (http://www.daviddarling.info/encyclopedia/L/lithopanspermia_Cathcart.html)-section 4.) The article discusses naturally occuring Verneshot panspermia, and artificial Verneshot affecting humanity "adversly"). The probability of artificial Verneshots accidentally causing the End of civilization (resolving the Fermi Paradox) is not calculated.
Template:Note 2003 Huang et al., "Huge rock eruption caused by the 1999 Chi-Chi earthquake in Taiwan", Geophysical Research Letters 30.
Template:Note See the 1994 Charlene Crabb New Scientist article about the "Jules Verne Launcher" (JVL): Shooting at the moon (http://www.newscientist.com/channel/space-tech/space-shuttle/mg14319373.900).