Welcome to the
Asteroid Doomsday Countdown Clock!
There are only..
days left until impact!
Friday, March 13, 1998 Published at 11:31 GMT
World
Nasa scientists say an asteroid which was feared to be on a collision course with Earth will now miss by 600,000 miles (965,600km).
Twenty-four hours earlier, experts said the mile-wide object could pass within 30,000 miles (48,280km) of the Earth and that it had the potential to create worldwide devastation if it hit the planet during its closest approach in October 2028.
The chances were put at 1,000-1. But after recalculations, experts now say the rock, known as 1997 XF11, will miss us by about 600,000 miles.
Space consultant and former rocket scientist Jim Oberg denied that observers had got their sums wrong, saying the asteroid was hard to track. "There are big numbers in space,"he said.
Beginning of the scare ....
The one-day space scare reportedly began when Brian G. Marsden, director of the Central Bureau for Astronomical Telegrams in Cambridge, Massachusetts, issued an alert.
The asteroid was added to the International Astronomical Union's list of 108 known "potentially hazardous objects".
"If it was only a few months away, we should be deadly worried,"Mr Marsden said. "But with 30 years, astronomers will solve the problem."
A s it was, only one day and some old photographs were needed to save the Earth.
Old photographs ....
Astronomers at Nasa's Jet Propulsion Laboratory dug out some eight-year-old pictures of the heavens taken by the Palomar Observatory telescope.
They found that the photos contained images of the asteroid which then was just an unidentified point of light.
Using the 1990 pictures and recent observations of the streaking space rock, they recalculated the orbital path of the asteroid and found that it would miss the Earth by 600,000 miles in its closest approach.
Steve Maran, an astronomer with the American Astronomical Society, said that Mr Marsden's calculations were based only on very limited data.
He said the Nasa astronomers "got more information about the orbit"and, in effect, had a total of eight years of orbital measurements about the asteroid.
He added: "They should have a much better estimate. This should certainly be more reliable because it is based on more data.
"You really do need an intensive set of observations to really nail it down."
Earlier warnings ....
Before the Nasa calculations, one expert, Dr John Gribben of Sussex University in England, had said: "There is about a one in 1,000 chance that it will hit the Earth. Those are very short odds.
"It is big enough to cause immense devastation. You are not talking about wiping out a city, you are talking about wiping out a continent."
Asteroid specialist Jack Hills had also speculated that the speeding space rock posed a real danger to Earth.
Mr Hills, a scientist at America's Los Alamos National Laboratory, said: "This is the first really big one to pass this close.
"This is the most dangerous one we've found so far. An object this big hitting the Earth has the potential of killing many, many people."
Asteroid 1997 XF11 was discovered on December 6 last year by the University of Arizona Spacewatch programme and was added to a list of 108 asteroids considered to be "potentially hazardous objects".
Mr Hills said an asteroid the size of 1997 XF11 colliding with the Earth at more than 17,000 miles an hour (27,360km/h) would explode with an energy of about 320,000 megatons of dynamite - the equivalent of almost two million Hiroshima-sized atomic bombs.
Widespread devastation ....
Depending on the collision site, it could cause mountainous tidal waves or a 20-mile-wide (30km) crater, throwing so much dust into the air that the Sun would be blotted out for weeks, Mr Hills said.
He added: "If one like this hit in the Atlantic Ocean, all of the coastal cities would be scoured by the tsunami. Where cities stood, there would be only mudflats."
Asteroids are routinely observed and plotted by astronomers around the world because of their potential for causing devastation on Earth.
Meanwhile, experts are still keeping watch. The International Astronomical Union said the asteroid would move out of view to all but the largest telescopes over the next few months.
But it will become more visible once again in 2000. And two years later, it is predicted to pass within about six million miles (965,600km) of Earth on Hallowe'en Eve.
But it will not, according to Nasa, collide with our planet.