asteroid

EXTINCTION BY VOLCANO, METEORITE, ASTEROID, OR COMET.

If the risks of human extinction by bio-terror, nuclear war, ecological collapse, resistant diseases, global warming, oil depletion, and water depletion were not enough, there is also the (not entirely negligible) possibility of human extinction by a volcanic eruption, or by meteorite or comet impact. If you think that I am exaggerating, read the following quotes from authoritative sources.

The following quotes are from the book Global Catastrophic Risks edited by Nick Bostrom (Director of The Future of Humanity Institute at Oxford University) and Milan M, Cirkovic (Professor of Cosmology in The University of Novi Sad (Serbia), published by Oxford University Press, 2012 – Article:- Hazards From Comets and Asteroids, by William Napier (25 years at The Royal Observatory, Edinburgh, and Honorary professor at Cardiff University)

Page 226:- “Civilisation ends with an impact bigger than a kilometre or two.” The author then tells us that there are some 1100 near-Earth asteroids over one kilometre across, and that, on this basis, an impact with such a body, with total human extinction, should occur once every 500,000 years. The author then adds an important caveat:- Extremely dark objects cannot be observed, AND WE DON’T KNOW HOW MANY THERE ARE. On this basis, impactions of more than one kilometre objects could occur more frequently than once every 500,000 years. Apparently we can only guess at the actual frequency.

Pages 227 to 229:- The author describes comet impacts upon Earth thus:- “THIS OUGHT OT MAKE THEM A SUBSTANTIAL RISK.” Her also mentions that, for whatever reason, we fail to observe most comets, and that comets “May indeed develop vanishingly small reflectivity” (ie:- they would be invisible to us) - - - - The author remarks regarding the dark comets (ie:- with small reflectivity, and therefore invisible to us):- “THE MAGNITUDE OF THE HAZARD THEY PRESENT IS LIKEWISE UNKNOWABLE.”

Page 230:- The author discusses “small relatively common impacts”. He suggests that an ocean impact could possibly lead to waves 4 to 7 metres high, “presumably with the loss of millions of lives.”

Page 233:- The author mentions impacts in 1908, 1930, and 1935.

Page 234:- The author mentions a “1000 megaton asteroid” - - - - “which will pass within six Earth radii in 2029” (My comment:- This is very close!)

Page 234:- The author remarks that “There is still considerable uncertainty in estimates of impact rate.”

Page 234:- The author mentions an asteroid strike circa 1450 in Australia that causes a 130 metre high mega-tsunami.

Page 234:- The author remarks:- “These lines of enquiry are quite new - - - - if they continue to hold up, THE CASE FOR A HIGH CURRENT RISK WILL IN EFFECT HAVE BEEN MADE.” (ie:- risk of impacts.)

Page 235:- The author remarks:- It remains possible that a large population of unstoppable dark bodies is being missed.”

Page 225:- The author tells us that The Oort Cloud contains 100 billion long period comets.

My comment:- Effectively, we could be hit by a large (dark) comet or asteroid at any time, without any warning. We would never see it coming. It is possible that the risk of such an impact is by no means negligible, and it could even be a high risk. Apparently civilization could end at any time.

The following quotes are from the book Global Catastrophic Risks edited by Nick Bostrom (Director of The Future of Humanity Institute at Oxford University) and Milan M, Cirkovic (Professor of Cosmology in The University of Novi Sad (Serbia), published by Oxford University Press, 2012 – Article:-Super Volcanism, by Michael R. Rampino, Associate Professor of Biology at New York University.

Page 213:- The author discusses the effects of a “super volcano” that spread dust into the atmosphere, blocking out the sunlight, causing “volcanic winter.” “Collapse of agriculture as a result of the loss of one or more growing seasons - - - - - followed by famine - - - - - could devastate the major food growing areas of the world. For example, THE ASIAN RICE CROP COULD BE DESTROYED BY A SINGLE NIGHT OF BELOW-FREEZING TEMPERATURES DURING THE GROWING SEASON. - - - - and 3 to 4 degrees centigrade (temperature drop) WOULD HALT ALL CANADIAN GRAIN PRODUCTION.” - - - - - The author tells us that predicting a super-eruption would be difficult. - - - - “These considerations suggest that VOLCANIC SUPER-ERUPTIONS POSE A REAL THREAT TOCIVILIZATION.” (My capitals.)

In case the above suppositions seem implausible, here are some quotes from the book Our Final Century, by Professor Martin Rees, published by Arrow Books, 2004. (He is the fifteenth Astronomer Royal, appointed in 1995, and was Master of Trinity College, Cambridge from 2004 to 2012 and President of the Royal Society between 2005 and 2010.)

Page 97:- “A super-eruption in northern Sumatra seventy thousand years ago - - - - ejected several thousand cubic kilometres of ash, ENOUGH TO HAVE BLOCKED OU THE SUN FOR A YEAR OR MORE.”

In the same book, discussing comet and asteroid impacts – Professor Rees tells us (page 90):- “COMETS AND ASTEROIDS ROUTINELY COME CLOSE ENOUGH TO BE A DANGER.”