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Earth in the crosshairs?

August 18, 2013

vancouversun.com

Our little planet faces many poorly understood perils from beyond

Earth in the crosshairs?

Photograph by: Associated Press, NASA , London Daily Telegraph, The Associated Press

Considering the dangers lurking out there, it’s a wonder that our little planet is not in the firing line more often. We are just 150 million kilometres from a star that, while mostly well-behaved, occasionally has temper tantrums that could bring our civilization to its knees. Our solar system is home to a swarm of comets, rocks, boulders and flying mountains, tens of thousands of which are big enough to wipe out anything from a small city to the entire biosphere. And further out lurk delinquent stars whose death explosions are the largest since the Big Bang. If one of these went off nearby, it would be curtains for all of us.

In fact, Earth can be considered rather lucky to have not suffered a total cataclysm in at least 3.5 billion years – the period during which we have an unbroken record of life existing on the Earth’s surface. Before then, global sterilization events, caused by collisions with huge space rocks, almost certainly took place many times – perhaps once every few hundred years. Each may well have wiped out early versions of life. Then, after one final cataclysmic impact, it was clear sailing all the way.

That was what we used to think, anyway. But in recent decades, it has become clear that our cosmic neighborhood, in more recent times, has not been as benign as was thought.

In the 1980s, for example, it was confirmed that Earth has been hit several times in its history by objects from space – none big enough to sterilize the planet completely, but a handful packing enough of a punch to change the course of life forever. The most famous of these was our collision with a nearly 10-kilometre-wide asteroid 65 million years ago, whose fiery passage into the Mexican coast has been blamed for killing off, or at least delivering the coup de grace to, the dinosaurs.

It is not just rocks we have to worry about. Japanese scientists have uncovered evidence from the study of tree rings that, in the year 775, the Earth was hit by a colossal solar flare. The scientists found a spike in radioactive carbon-14, taken up by the ancient cedar trees they were studying.

In Finland, Ilya Usoskin and his colleagues found an identical spike on the other side of the world. One theory is that this was caused by a nearby exploding star – a supernova – showering the Earth with radiation.

The trouble, says Usoskin, was that they could see no sign in the skies of a supernova remnant within the required distance. So the scientists turned to the historical record to see whether there were any clues. The handful of supernovae that have burst into existence in historical times have often been well recorded. But, 1,238 years ago, there were reports not of a brilliant “new star” but – as one English chronicler, Roger of Wendover, put it – of the skies themselves catching fire: “Fiery and fearful signs were seen in the heavens after sunset; and serpents appeared in Sussex, as if they were sprung out of the ground, to the astonishment of all.”

This was, says Usoskin, probably an account of an aurora borealis – the Northern Lights.

“Anyone who has seen aurorae knows they look like serpents,” the Finnish scientist told New Scientist this week. The conclusion is that the Earth was hit by a huge mass of charged particles ejected from the Sun.

This was far from a one-off: such flares probably happen every few centuries or so. In late August and early September 1859, the Earth was hit by a smaller flare that had equally dramatic effects. Named the Carrington Event, after the astronomer who documented it fully, the solar storm caused Californian Gold Rush miners to be woken in their tents by the bright northern lights. Aurorae were seen as far north as Queensland in the southern hemisphere and as far south as Washington in the northern.

But there was also a chilling foretaste of what would happen if such an event were to repeat itself today. For the surge of charged particles had a dramatic impact on the nascent telegraph systems of the world.

Telegraph wires were shortcircuited, copper cables melted and some operators were given bad electrical shocks. There was no domestic electricity, no telephones and no radio. If a rerun of the Carrington Event were to happen tomorrow, it would be cataclysmic: power lines would melt, electrical sub-stations would catch fire, half the world’s telephone grid would be knocked out, telecoms satellites would go down and the Internet would be crippled, perhaps for a year.

Just repairing the power lines would take weeks. In June, a joint U.K.-U.S. study, led by insurers Lloyd’s, estimated that a superstorm of this magnitude would cost the world £2.5 trillion (about $4 trillion), and tip the planet into depression.

Yet when it comes to such threats from space, we suffer from profound short-sightedness. Asteroid strikes, for example, are seen as the stuff of bad Hollywood films – or at least they were until Feb. 15 this year, when the Russian city of Chelyabinsk was blasted by a 10,000-ton meteor that exploded at 48,000km/h about 16 kilometres overhead.

The blast, comparable to a small nuclear weapon, caused havoc on the ground, smashing windows and injuring more than 1,000 people, some seriously.

A hundred and five years earlier, Tunguska, also in Russia, was hit by an even bigger rock, or comet, that could have flattened Moscow or London if its trajectory had been only slightly different.

As well as being shortsighted, we are also ignorant. Solar storms in particular are poorly understood. Some are high-energy yet do little damage; other, more modest eruptions can cause chaos, such as the 1989 flare that knocked out the power grid in Eastern Canada. It is now thought that the biggest – such as the 775 event – may be the result of huge comets colliding with the Sun. According to David Eichler, an Israeli physicist at Ben Gurion University, a “sungrazer” comet 80 kilometres wide hitting the sun at 1.6 million kilometres an hour would generate enough energy to cause a solar flare that, if it hit the Earth, would be far more severe than even the Carrington Event.

There may be other weird things going on above our heads that we do not understand at all.

Meteorologists have long thought that thunderstorms are caused by electrical charges building up in ice particles suspended in clouds. The trouble is, according to Russian physicist Alexander Gurevich, there simply isn’t enough energy to make the lightning flashes we see.

He proposes instead that these electrical discharges must be “seeded” in some way. His proposed mechanism involves cosmic rays – high-energy sub-atomic particles created by exploding stars and colliding black holes in distant galaxies – that cause a “runaway electron breakdown” by ionizing the water in the atmosphere, generating immense electrical charges. If he is right – and his is still a controversial theory – the next time you see a lightning strike, you may be witnessing something triggered by an exploding star or burping black hole millions of light years away.

CIA confirms Area 51 is real

The truth is out there – or at least some of it.

UFO buffs and believers in aliens are celebrating the CIA’s clearest acknowledgment yet of the existence of Area 51, the topsecret Cold War test site that has been the subject of elaborate conspiracy theories for decades. But the revelations, which have set the tinfoil-hat contingent abuzz on the Internet, aren’t quite The X-Files or Independence Day. There’s no mention of UFO crashes, blackeyed extraterrestrials or staged moon landings.

The 407-page document contains many redactions, however, so much fodder for the imagination still exists.

The CIA history, released Thursday, not only refers to Area 51 by name and describes some of the activities that took place there, but places the U.S. air force base on a map, along the dry bed in Groom Lake, Nev. It also describes some cool planes, though none of them are saucer-shaped.

George Washington University’s National Security Archive used a public records request to obtain the CIA history of one of Area 51’s most secret Cold War projects, the U-2 spy plane program.

National Security Archive senior fellow Jeffrey Richelson first reviewed the history in 2002, but all mentions of the country’s most mysterious military base had been redacted. So he requested the history again in 2005, hoping for more information. Sure enough, he received a version a few weeks ago with the mentions of Area 51 restored.

It’s not the first time the government has acknowledged the existence of the super-secret, 8,000-square-mile installation. Former presidents Bill Clinton and George W. Bush referred to the “location near Groom Lake” in insisting on continued secrecy, and other government references date to the 1960s. But Richelson as well as those who are convinced “the truth is out there” are taking the document as a sign of loosening secrecy about the government’s activities in the Nevada desert. Some UFO buffs and others believe the most earth-shattering revelations will come from Area 51 workers, not an official document.

“The government probably will not release what it knows,” UFO researcher Robert Hastings said. “My opinion is that whoever is flying these craft will break the story and will reveal themselves at some point in the future. The CIA is not going to release anything they don’t want to talk about.”

The site is known as Area 51 among UFO aficionados because that was the base’s designation on old Nevada test site maps. The CIA history reveals that officials renamed it Paradise Ranch to try to lure skilled workers. Beginning with the U-2 in the 1950s, the base has been the testing ground for a host of top-secret aircraft, including the SR-71 Blackbird, F-117A stealth fighter and B-2 stealth bomber. Some believe the base’s Strangelovian hangars also store alien vehicles, evidence from the “Roswell incident” – the alleged 1947 crash of a UFO in New Mexico – and extraterrestrial corpses. The CIA history mentions an “unexpected side-effect” of the high-flying planes: “a tremendous increase in reports of unidentified flying objects.” The U-2 and Oxcart planes, which flew higher than civilians believed possible, accounted for half of UFO sightings during the 1950s and ’60s, according to the report.

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