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Asteroid heads for Earth
September 2, 2003
Scientists were today warning of a possible asteroid collision with the Earth.
An asteroid around 1.2 km wide could hit the earth on March 21, 2014 and has been classified as "an event meriting careful monitoring" by astronomers.
But they say the probability of the asteroid hitting Earth is just 1 in 909,000 and the risk of impact is likely to decrease as they collect more information.
The newly-discovered asteroid, known as 2003 QQ47, has a mass of around 2,600 million tonnes.
Its orbit calculations are currently based on just 51 observations during a seven-day period.
Dr Alan Fitzsimmons of Queen's University, Belfast, one of the expert team advising the UK NEO (Near Earth Objects) Information Centre, based in Leicester, said: "The NEO will be observable from Earth for the next two months, and astronomers will continue to track it over this period."
The giant rock was first observed on August 24 by Lincoln Near Earth Asteroid Research Program (LINEAR), based in Socorro, New Mexico.
The observations were reported to the Minor Planet Centre in Massachusetts, a centre for all new discoveries of asteroids and comets. The asteroid has been given a classification - known as a "Torino hazard rating" of one - defining it as "an event meriting careful monitoring."
Scientists said it was likely to drop down the scale for hazard as more observations were made.
Kevin Yates, project manager for the UK NEO Information Centre, said: "As additional observations are made over the coming months, and the uncertainties decrease, asteroid 2003 QQ47 is likely to drop down the Torino scale.
"The NEO Information Centre will continue to monitor the latest results of observations and publish regular updates on our website."
Asteroids such as 2003 QQ47 are chunks of rock left over from the formation of our solar system 4.5 billion years ago.
Most are kept at a safe distance from Earth in the asteroid belt between the orbits of Mars and Jupiter.
But the gravitational influence of giant planets such as Jupiter can nudge asteroids out of these safe orbits and send them plunging into the Earth's neighbourhood.
This story was found at: http://www.theage.com.au/articles/2003/09/02/1062403508365.html
Asteroid Doomsday 'Risk' Evaporates after Media Fan Flames
A newly discovered asteroid that generated doomsday headlines around the world yesterday morning was, by the end of the day, reduced to innocuous status as additional observations showed it would not hit Earth.
Meanwhile, a whirlwind of media hype has astronomers and asteroid analysts arguing among themselves -- again -- about how they should disseminate information to the public.
By one expert account, it was business as usual in the Near Earth Object (NEO) community, a loose-knit group of global researchers who find, catalogue, analyze and frequently spout off about asteroids that might one day slam into our planet.
Asteroid 2003 QQ47 was discovered Aug. 24 by the Lincoln Near Earth Asteroid Research Program (LINEAR).
Based on limited data collected during just a few days in late August, astronomers at first could not rule out the possibility that the giant rock would hit Earth. They gave it 1-in-909,000 odds of impact in 2014 and catalogued it as a 1 on the Torino hazard scale, a designation that merits "careful monitoring."
Its size -- three-quarters of a mile wide (1.2 kilometers) -- explains some of the attention 2003 QQ47 received. Were a rock that big to hit Earth, the climatic consequences would be global and it would cause, at the least, widespread regional devastation.
But only a zero rating is lower on the Torino scale, which goes as high as 10.
Astronomers agree that a rating of 1 is not cause for public concern.
Most experts do not believe the mainstream press should waste time reporting on such an object. Several other newfound asteroids receiving similar designation in recent years have fallen off the list within days, as more observations allowed for refined orbital projections.
Nonetheless, a press release issued early Tuesday by the British government's Near Earth Object Information Center fueled widespread media coverage, including a wire story by Reuters that many asteroid experts saw as inflammatory.
Headlines were over-the-top, most researchers felt. They included "Armageddon set for March 21, 2014" and "Earth is Doomed."
By late yesterday, however, more observations allowed astronomers to conclude there was no chance for impact in 2014.
The incident was just one in a long series miscues involving astronomers, their public relations efforts, and a media eager to report potential doom.
"It would appear that all the lessons learned from five years of our PR blunders, media gaffes and errors of judgement have been forgotten," said Benny Peiser, a social anthropologist and asteroid analyst at Liverpool John Moores University in the UK.
A handful of similar scares -- about one per year -- have evaporated in similar fashion as professional astronomers go about their business of finding and tracking potentially dangerous asteroids.
The NEO information Center, whose press release ignited the latest fiery press coverage, issued a follow-up statement early this morning.
"The NEO Information Center aims to keep the public and media informed of these kinds of issues, as they unfold rather than after the fact," today's statement said. "This approach ensures we can promote understanding of the process of asteroid detection, tracking and risk assessment."
Kevin Yates, project manager for the center, had said in the original press release that additional observations would likely reveal a reduced risk.
Today, Yates said, "Openly sharing this sort of information, in a non-sensationalist way, should help to dispel the popular myth that governments and astronomers would keep the discovery of a dangerous asteroid secret. I hope the coverage of this story will give the general public more of a feel for how the assessment of risk evolves over time as more observations are made."
The NEO Information Center's statement today concluded with a bizarre note of praise for the media that sounded defensive to others in the NEO community.
"The NEO Information Center would like to thank the media for what, on the whole, has been responsible coverage of this story. Almost all of the press and broadcast coverage has included reference to our original statements that the probability of impact was very low at just 1-in-909 000, and that the Torino rating was likely to drop following further observations."
"Undermining our integrity"
Peiser did not share the center's rosy view for how the whole thing unfolded. He runs an electronic newsletter called CCNet, a forum for discussing the research and risks associated with NEOs, as well as the impact of media coverage on the public view of asteroid research and the credibility of the researchers.
"I'm afraid that any attempt to justify an ill-timed and unnecessary media campaign doesn't bode well for the NEO community's efforts to avoid false asteroid alarms that only risk undermining our integrity," Peiser wrote in the latest edition of CCNet today.
Peiser leveled this accusation at the center: "Crying wolf becomes official policy."
The first and most notorious false asteroid alarm dates back to 1998. Then an astronomer went public with data showing that asteroid 1997 XF11 had a chance of hitting Earth in the year 2028. Once the asteroid was rendered harmless by more observations, a debate began as to if, when and how to release preliminary asteroid data to the media and the public.
Though new agencies, institutions and programs have since been set up to better manage the situation -- the NEO Information Center is itself just a year old -- little has changed. A similar scare developed last summer, when British media hyped the potential danger of 2002 NT7. In that situation, astronomers were candid and vocal in their criticism of the British press.
Like the return of Elvis
One thing has changed of late: There is increasing sarcasm in the media with each new asteroid alert. Some reporters and editors are getting wise to the long odds -- or perhaps tired of having to report on them -- and doing more than just sensationalizing the data.
One story yesterday made light of the initial chances of 2003 QQ47 hitting Earth.
Sky News, a British publisher, said a bookmaker was taking bets on the prospect. A spokesman for William Hill bookmakers likened the 1-in-909,000 odds of doom to the chance that a manned expedition to Mars would arrive and discover the Loch Ness Monster there, or the equally probably scenario that Elvis Presley would reappear and marry Madonna.
We now know that the latter two scenarios are far more likely than the world ending in 2014 due to an impact by asteroid 2003 QQ47.
The articles above highlight the unexpectedness of the threat of asteroids hitting the earth and the hysteria such reports can generate in the media before subsequently being downgraded.
An explanation of how the risk changes/lessens as an asteroid gets closer to earth is shown in the following animated gif.
For a really good site with information on this topic visit: http://www1.tpgi.com.au/users/tps-seti/spacegd7.html
Vulnerability the East Coast of Australia to a 10m Tsunami
Irrespective of the cause, there is a need to assess the risk to coastlines from tsunami caused by an asteroid impact. The south east coast of Australia makes an sobering case study. This coastline covers about 1,500 km from the Sunshine Coast in Queensland to Eden in New South Wales. Many low lying coastal areas along the south east coast of Australia have been intensively developed. Excluding the non-coastal suburbs of Sydney and Brisbane, the total population along this coastline is about 1.2 million.
Consider the effects of a 10m tsunami like the one which hit northern New Guinea in July 1998. Based the topography of coastal developments along the south east coast of Australia it is conservatively estimated that about 50,000 dwellings, containing about 140,000 people (about 12% of the population), are in areas which could be inundated by a 10m tsunami. If it is assumed that these people are in or near their dwellings (or similar vulnerable areas) for 50% of the time and that the death rate from people caught in such a tsunami is 50% then it is expected that 25% of the population would be killed#. The predicted death toll from one event which caused a 10m tsunami along the south east coast of Australia is therefore 35,000 (25% of 140,000). This could easily double during peak summer periods.
Based on the above predictions, and assuming a run-up factor of 10, the chances of an asteroid-generated tsunami event occurring in the next fifty years are estimated to be about 1 in 20,000 - a low risk but high consequence event. For comparison, Ward & Asphaug (1999) include a site-specific calculation of tsunami risk for Sydney. They estimate there is a 1.15% risk of a 10m or higher tsunami in the next 1,000 years - this is equivalent to a 1 in 1,700 chance in 50 years.
Research by the University of Wollongong suggests that the New South Wales South Coast has been struck by at least six large tsunami within the last 6,000 years - a typical interval of 1,000 years - perhaps much less ( Young et al 1995). One possible cause is giant underwater "landslides" on the edge of the continental shelf but earthquakes and asteroid impacts may also be causes. Irrespective of the risk of tsunami from asteroid impact we really need to learn more about the risk to our coastlines from major tsunami.
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