Planetary Defense – Who Will Save Earth? – - Neo is the cosmic threat to civilization Survival – What are your chances of dying from impact an asteroid?
What would happen if something the size of a mountain, flying at 26 000 miles per hour (41 843 kph), hit the Earth? "Our governments have a plan in place to protect us from such a calamitous event? Judging by the slow response of government, both before after Hurricane Katrina is likely the answer is 'no'.
We live in a solar system busy with a lot of moving parts. Many of the parts consist of iron stone materials known as asteroids and many of these rocky bodies have not yet been discovered and could impact with Earth at any time.
There are also many icy bodies known as comets. They live beyond the orbit of Neptune. Any agitation of their orbits, perhaps nudged by gravitational forces of nearby stars can change their trajectories for a visit in the inner Solar System putting them in a potential collision course with Earth, also at any time.
Recent scientific studies Developments
In January 2008 there was some news that an asteroid, known as 2007 WD5 may hit Mars. The resulting impact is expected to be similar in size to Meteor Crater, an impact crater one mile wide, in Arizona, formed in a flash of white light and fireball, when an asteroid struck there 50 000 years ago.
Around the same time, another asteroid known as 2007 TU 24 was discovered in November 2007 by the Catalina Sky Survey on 11 October 2007. Calculations determined that pass near Earth on 29 January 2008, just outside the orbit of the Moon, which is considered very close in astronomical terms.
2007 TU 24 is between 150 and 600 meters in diameter. The average interval between actual impacts Earth to an object of this size is estimated at around 37 000 years. Radar observations of 2007 TU 24 was made at Goldstone, California, in late January and early February. This will permit later 3D shape reconstruction.
In July 1994, twenty fragments of comet Shoemaker-Levy 9 smashed into Jupiter, leaving brown spots and black on the planet for over a year, every patch of the same, the size of Earth. Astronomers have not yet have witnessed an asteroid impact with another planet.
Therefore, the opportunity to witness the 2007 WD5 impact on Mars was exciting to astronomers and scientists they wanted to make measurements of such objects, as well as calculations and impact scenarios of what could happen that an asteroid or comet, the impact with Earth.
The Mars impact never took place, as the asteroid passed by without incident, a disappointment to astronomers who have lost the opportunity to observe the direct effects of an asteroid impact on a planet similar to Earth.
Fortunately for us, however, the asteroid 2007 TU 24 also lost Earth. I could not help wondering what really would have responded if the scientists had told us that the Earth bound asteroid headed straight to us and that according to their calculations there was no way to be surprised!
How worried should?
One of the main problems we have now is the lack of an effective response. Even if we knew that an asteroid or comet was headed straight for us, and although there plenty of warning ahead of time what would we do? Once detected, we still seek a way to reliably and safely destroy or deflect them. To date, these methods do not exist in the practicum, only in theory. No missions to demonstrate the ability to move or destroy an asteroid or comet has been carried out by any country.
If an asteroid were to hit Earth, impact would likely be in the oceans and land is more than 70% water. The effects of such impacts could include tsunamis, which would be devastating for small island nations and coastlines on land on both sides of the ocean, or it could be as devastating as planet-wide environmental collapse if the projectile is large enough to cross the ocean.
An asteroid could hit the earth, including cities, again causing anywhere from local to global devastation depending on the size of the impactor. Food chains, transportation, all infrastructure could be leveled, with a moderate impact and civilization itself may be in danger.
A major impact could endanger the survival of the planet, not only food chains and civilization, by raising tons of dust and soot high into the atmosphere, similar to giant volcanic eruptions that block sunlight and climate change, killing off vegetation as temperatures plummet and no access to solar energy for photosynthesis.
When looking at the Moon, Mercury, Mars and even Earth itself, we can see the pock marks that tell the story of their histories. As the Moon and Mercury is not subject to the forces of erosion, their battle-worn landscapes bear the scars of countless impact craters are repayable on hard reminders of the reality of life on every planet in the brutal environment of space. These pockmarks should act as a reminder that "not a question of whether a impact is going to happen but when! "
According to David Morrison of NASA-Ames in an article he wrote in September 1998 on average a NEO with about 1 million megatons energy (roughly 2 km in diameter) collides with the Earth once or twice per million years, statistically speaking. An impact of this size would kill a substantial proportion of the population of Earth and has a devastating and lasting effect on the environment of Earth. What statistics do not tell, of course, is whether the impact shall be one million years from now or a week from today. What is interesting to note is that the impact that most scientists believe is responsible for causing the extinction of the dinosaurs occurred 65 million years. What good can we do for a long time by an extinction-level strike.
Is anyone doing something about this situation?
U.S. Military budgets do not include protection of the Earth. The U.S. Army not even have a mission to worry about it. The military program in all countries is to defend their country interests. To date, the NEO are not relevant to any military officer. No country or group of countries has undertaken work, officially, to protect the Earth of nearby objects.
They were an imminent impact to happen, would the government (s), even telling us anything? We have already determined that governments are unwilling to intercede, intercept and save the day. In February 2008, the U.S. Air Force shot down a U.S. spy satellite in orbit. The satellite was traveling at speeds of asteroids, at 23 000 miles per hour. Impressive as that was, to save Earth from an impending impact?
"Guardians of Space around the world are hunting for these potentially hazardous near-Earth objects. (That term, Guardians of Space, was created by me and the basis of Sir Arthur C. Clarke 's novel "Rendezvous with Rama", which included a NEO search program called Space Guard. Sir Arthur C. Clarke thanked much that reference.)
The U.S. top searches based on the study of the sky are more productive, the Catalina Sky Survey, run by Steve Larson, with searches in both northern and southern hemispheres. The remaining searches are all uniquely situated in the northern hemisphere, with money provided by NASA. These include: Air Force U.S. linear program operated by the Lincoln Laboratory, run by Grant Stokes and NEAT (Near Earth Asteroid Tracking) JPL run operation. Spacewatch is another search NEO founded by Tom Gehrels and Robert McMillan and directed by Robert McMillan, based near Tucson, Arizona. Finally, at the Lowell Observatory in Flagstaff, Arizona, has a search called LONEOS (Lowell Observatory Near Earth Object Search), directed by Ted Bowell. There are also countless amateur astronomers around the world that help in monitoring of known asteroids (sometimes even find some new ones themselves).
Luck is a sensible strategy?
We know what will happen. It's inevitable. We have witnessed the impacts on other worlds. Scientists are convinced that it was a comet that wiped out the dinosaurs 65 million years.
The big impact at Tunguska in 1908 is the largest event of its kind on Earth. Fortunately, it exploded in an uninhabited region of Siberia, and only one person died as a result. However, the explosion was equal to that of Hiroshima and the trees were felled for miles around the impact site remain so today.
While very few people on Earth consider these very real dangers from space, thousands of relentless NEO is traveling in silence through the night go on indifferently about your business.
More
Videos
For a deep understanding of the NEO hazard and what is being doing about it, see the original movie on this subject, "Planetary Defense".
"The Planetary Defense" speaks with military experts, scientists and government about the dangers we face today and plans to deal with NEOs in the future. The film also features eminent science fiction writer Sir Arthur C. Clarke and Apollo 9 astronaut Rusty Schweickart, who will advise the UN on the NEO risk in 2009.
The movie lasts 48 minutes and has about an hour Features bonus in the form of two presentations in silence. A slide show displays a collection of asteroids and comets from NASA, JPL and other sources, and the other is dedicated to impact sites on Earth.
Find out more about the film, planetary defense in http://www.SpaceViz.com
Online
For more information visit http://impact.arc.nasa.gov About the NEO. There may find a wide coverage of NEO by David Morrison of NASA-AMES.
A plethora of other material on the NEO hazard can be found online.
About the Author
Space Viz is a film maker, musician, editor, interviewer and author, based on Earth, with one child and a planet to save.
Space Viz has a Science background and a Fine Arts degree. He is a science buff, an amateur astronomer and speaks at Special ‘Science’ Events throughout the world. He is often invited to speak (or Key Note Address) to the general public-at-large in a succinct, educational and entertaining way about astronomical phenomena. His advice is sought after by the local media and press.
Special interests and expertise also include dogs (and pets in general); music composition and publishing; and independent film production and distribution.
Visit Space Viz at http://www.SpaceViz.com
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