AN ASTEROID plunging into the Pacific Ocean would spark a tsunami that would wipe out “the entire west coast of North America”, a scientist warned.
Apophis 99942 is a 370-metre-wide near-Earth space rock that caused a brief period of concern in December 2004 when initial observation indicated a probability of up to three percent that it could hit Earth on April 13, 2029. However, in 2006 scientists ruled that date out, determining that Apophis could pass through a gravitational keyhole – a tiny region of space where a planet’s gravity is altered. Researchers calculated it might set up a future impact exactly seven years later – on April 13, 2036.
However, the likelihood of a direct impact in 2036 is now all but impossible, with just a 1-in-150,000 chance of a collision in 2068.
Neil deGrasse Tyson warned what would happen if the rock did crash into Earth.
The American astrophysicist and author revealed his research during a public lecture with Ryan Watt in San Francisco in 2008.
He said: “In the era of observing the cosmos with technology, this will be the closest biggest thing we will ever see.
“The orbit we now have for it is uncertain enough, because these things are hard to measure, we cannot tell you exactly where that trajectory will be.
“We know it won’t hit Earth, we know it will be closer than the orbiting satellites.
“But there is a 600-mile zone – we call it the keyhole – and if the asteroid goes through the middle of that it will hit the Earth 13 years later.
“It will hit 500 miles west of Santa Monica.”
He went on to explain how an impact in the ocean would cause a tsunami, adding: “If it goes through the centre, it will plunge down into the Pacific Ocean to a depth of three miles, at which point it explodes, caveatting the Pacific in a hole that’s three miles wide.
“That will send a tsunami wave outwards from that location that is 50 feet high.
“Oceans don’t like having holes in them, so this three-mile-high wall does what? It collapses.
“It falls back into the hole sloshing against itself with such ferocity that it rises high into the atmosphere and falls back down to the ocean, caveating it again.
“This cycle takes about 50 seconds, you can calculate it.”
He then revealed the sobering prospects for North America in such a scenario.
He continued: “So there you are on the beaches of Malibu and a tsunami comes in.
“The first wave needs a supply of water to exist, so the next wave actually sucks back on it to create itself.
“Whatever was there on the coastline is now brought back out to sea and the next tsunami brings it back to the shore.
“So what happens is, all the artificial stuff, all the houses, factories, they get churned into the force that sandblasts the entire west coast of North America clean.
“It’s April 12, 2029, and if it threads the keyhole it will hit Earth on April 13, 2036.”
Despite his claims, the keyhole has since been determined to be less than 600 metres wide, meaning the possibility of Apophis passing through it is extremely unlikely.
In 2008, NASA reaffirmed the chance of Apophis impacting Earth in 2036 as being 1 in 45,000.
However, in February 2014, the odds of an impact on April 12, 2068, were calculated by the JPL Sentry risk table as 1 in 150,000.