Past and possible future catastrophes due
the collision of the Earth and an asteroid
The Earth has a finite lifetime, thanks to natural processes within the Sun. Cosmologists believe that about 5 billion years from now, the sun will run out of Hydrogen, transition to a "red giant" state, and enlarge greatly in diameter. It may grow to encompass the Earth and its orbit, thus ending any possibility of life continuing on the planet. However, long before this will ocurr, the Earth is certain to experience collisions by numerous large asteroids, each with a devestating effect on humans, animals, and plants.
Near collisions between objects in space and the Earth occur very frequently. However, almost all are harmless because they are small objects that burn up in the atmosphere before reaching the Earth's surface. They can be seen at night as "shooting stars" or "falling stars." Occasionally, one will reach earth as a small meterorite.
On 2013-FEB-15, an unrelated pair of events ocurred.
- A meteorite -- 3 to 30 foot wide chunk of rock weighing an estimated 10,000 tons -- exploded over Chelyabinsk in western Siberia. The explosion had an energy level of almost 500 kilotons of TNT. This is approximately equal to 30 Hiroshima-class nuclear bombs. Such events occur every few years, somewhere on Earth.
DA14, a 45 foot wide asteroid passed by the Earth without entering the atmosphere. If there had been a collision, it would have involved much greater energy than the Chelyabinsk meteorite, but much less destructive than the collision of 1918. The latter also happened in Siberia, and was the largest impact event on Earth in recorded history. 16
However, sometime in the future, a large asteroid is certain to be on a collision trajectory with earth. Scientists at the Near Earth Asteroid Tracking project at NASA's Jet Propulsion Laboratory estimate that there are between 500 and 1,000 large objects which have a diameter of 1 kilometer (0.6 miles) or more in near-Earth orbit. They estimated that they had identified 15 to 20% of these asteroids by mid-1999.
Scientists in tracking stations in California, Massachusetts and Arizona expected to locate 90% of the biggest near-Earth objects by the year 2010. 7 If one of these asteroids is on a collision course with Earth and is not pulverized and scattered, or deflected, it has the potential to cause massive damage to the environment. Such an asteroid may come next month, or may be delayed for tens of millions of years. But it is coming! Scientists estimate that there is between once chance in 1,000 and one chance in 10,000 that a "doomsday" asteroid collision will head towards earth sometime during the 21st century.
A web site at the University of Pisa in Italy collates the latest information on asteroids. 8 H. Ja Melosh and Gareth Collins have placed a computer program online that estimates:
"... the regional environmental consequences of an impact on Earth. This program will estimate the ejecta distribution, ground shaking, atmospheric blast wave, and thermal effects of an impact as well as the size of the crater produced." 9
According to the Capital Weather Gang at the Washington Post:
"Scientists consider asteroids as potentially hazardous only if their size is larger than 490 feet in width."
That is about 150 meters. It is not clear what the term "hazardous" means in this context. The meteorite that blasted the mile-wide crater in Arizona was only 100 meters wide. Imagine what it would do if it landed in an urban area!
Past asteroid collisions:
Examples of large asteroids that have hit the Earth, and a recent one that had a near miss:
About 65 million years ago: There is a widespread belief among palentologists that an asteroid about 10 km (6 miles) in diameter hit the ocean near the Yucatan peninsula. [Of course, this dating is rejected by young earth creationists who believe that the Earth is less than 10,000 years old]. The explosion appears to have contained the equivalent of more than a billion times the energy of the bombs dropped on Nagasaki and Hiroshima." 1 It created the Chicxulub Crater that is oval in shape, and about 180 km (110 miles) in diameter. Additional evidence for this event is the presence of a layer of rock found in many places around the world. It contains a concentration of iridium that is much higher than normal -- "30 times and 130 times background in the two sections originally studied." 1 A sample of this layer in a rock from Wyoming has 1,000 times the concentration of iridium when compared to the layers directly above and below it. Iridium is rare on earth but common in most asteroids and comets.
A U.S. - Czech team of scientists believes that they have figured out the source of the asteroid that wiped out the dinosaurs and many other species about 65 million years ago. Using astronomical observations and computer simulations, they estimate that the original asteroid was about 170 km (106 miles) wide and located in the asteroid belt between Mars and Jupiter. About 165 million years ago, it hit another asteroid -- one that was about one third as wide. The collision created thousands of large chunks of carbonaceous chondrite asteroids which are called "Baptistina family asteroids." The researchers are 90% certain that one of these collided with the earth to form the Chicxulub Crater on Mexico's Yucatan Peninsula about 65 million years ago. They are 70% certain that the massive Tycho crater on the moon was made by another Baptistina asteroid. One of the researchers, David Nesvorny of the Southwest Research Institute in San Antonio, TX, said that a bombardment of Baptistina asteroids over the last 100 to 150 million years "...produced a surge in the impact [rate] that peaked roughly 100 million years ago." William Bottke, also from the Institute, said:
"We are in the tail end of this shower now. Our simulations suggest that about 20 percent of the present-day, near-Earth asteroid population can be traced back to the Baptistina family." 11
A few of other asteroid-Earth impacts ocurred at approximately the same time as the asteroid that produced the Chicxulub Crater. They may also have belonged to the Baptistina family and may have contributed to the devastation.
The Chicxulub Crater asteroid impact apparently created a massive dust cloud that blocked sunlight from reaching the Earth for as long as a year. It would have also injected sulfuric acid aerosols into the stratosphere. Megatsunamis appear to have hit many Caribbean islands and eastern U.S. states. The end result was horrendous: the extinction of many types of plants and animals, including the apparent extinction of all of species of dinosaurs. Almost all scientists believe in the Theory of Evolution, and have concluded that the disappearance of the major land-based predators at that time allowed small rodent-like mammals -- our ancestors -- to thrive. On a positive note, without the asteroid impact(s), intelligent life may not have evolved on Earth. [Of course, some people believe -- with considerable justification -- that intelligent life has yet to evolve on this planet.]
About 48,000 BCE: A meteorite about 50 meters (150 feet) across hit the ground near Winslow, AZ, and produced the famous "Arizona Meteor Crater." It is about a mile across, 2.4 miles in circumference and more than 550 feet deep. The energy dissipated was the equivalent of 20 million tons of TNT, about equivalent to 1,000 Hiroshima type nuclear bombs.
1908-JUN-30: A meteorite about 50 meters (160 feet) in diameter exploded at about 6 km (3.7 miles) above the Earth's surface in a largely uninhabited area in Siberia. Some reindeer herders about 30 km (20 miles) away were blown into the air; some were knocked unconscious; one died. Trees up to 15 km (10 miles) away were blown over. Fires were ignited up to 30 km (20 miles) away from the blast. 2
1972: A 1,000 ton object approached the Earth at a narrow angle over the Grand Tetons in Wyoming, heading North. It bounced back into space like a skipping stone when it encountered the outer atmosphere. Otherwise it would have hit somewhere in Canada and produced an explosion with energy roughly equal to the nuclear bomb over Hiroshima, and a little smaller than the Siberian collision. 2
- 2009-MAR-02: The Earth experienced a near-miss on when asteroid 2009 DD45 passed about 48,800 miles from Earth above the Pacific Ocean near Tahiti. That is about twice the height of some geocentric telecommunications satellites and about one fifth of the distance to the moon. It is about 33 meters (110 feet) in diameter, similar in size to the asteroid that exploded above Siberia in 1908. One sobering thought is that it was only discovered two days before its closest approach. 10
2011-JUN-27: Asteroid "2011 MD" was discovered on 2011-JUN-22 by LINEAR -- a pair of robotic telescopes in New Mexico that scan for near-earth asteroids. Its closest approach to Earth was on JUN-27 when it was only 12,000 km (7,500 miles) away. That is about 3% of the distance from the Earth to the Moon. It is estimated to be 9 meters (30 feet) wide. An asteroid like this one comes this close to Earth about every 6 years.
Future possible asteroid impacts and near misses:
2011-NOV-08: Asteroid 2005 YU55 is a roughly circular object about a 400 meters (one quarter-mile) wide object. If it collided with the Earth, it would produce a crater about 6 km (four-miles) wide, and 1,700 feet deep. It would probably land in the ocean where it could generate a 70 foot high tsunami. At contact, it would generate shaking equivalent to a magnitude 7 earthquake.
Fortunately, it will not collide with the Earth on this pass. The closest that it will come is about 324,600 km (201,700 miles) away on 2011-NOV-08 at 6:28 PM. At that time, it will be about 85% of the distance between the Earth and moon. The asteroid will have no significant effect on the tides or to the Earth's tectonic plates. 3
That is the good news. The bad news is that NASA scientists have been able to predict accurately the asteroid's path only for a couple of hundred years into the future. The predict no collissions over that interval.
2011 to 2024: A web site titled "Fire from the sky: Meteors and Biblical Prophecy," once predicted that a meteor (actually a meteorite) "could" hit the earth sometime between 1998 and 2023. This would cause fireballs of debris, tidal waves, supher [sic] dioxide, a 'red tide' in the oceans, and a dust cloud." 4
2014-MAR-21: "Osiris the Alpha and Omega," a.k.a. the Son of Man, formerly known as Osiris, then Mithra, then Jesus Christ, has announced that he is on Earth, staying in a hotel in Uruguay. He is part of the Holy Trinity with his Father RaHorus (God), and sister Isis. His brother is Set-Hen (Satan). He predicts that on 2014-MAR-21, asteroid qq47 will hit Earth, causing a six month nuclear winter and the start of a new ice age. He also predicted an economic Armageddon starting on 2011-JUN-18, to be followed with an Al Queda attack on New York City, Los Angeles and Houston on 2011-JUL-04, none of which actually happened. He predicts that on 2011-NOV-19, a 150 megaton nuclear bomb will be detonated in Israel. On 2012-FEB-28, a volcano in French Montserrat Island will erupt. I will keep Osiris' Email on file in the event that some of these actually happen even though the odds are astronomical that they won't.
Path of 2004 MN4 on 2029-APR-13
The short white bar indicates the degree of uncertainty.
The Earth's gravitational pull will bend the trajectory of the asteroid by about 28º. This makes its future path impossible to predict at this time. Some media outlets have speculated that it may hit the Earth on its next pass circa 2036, but this is unlikely to the extreme.
The International Astronomical Union's Minor Planet Center maintains a list of predicted close-encounters by PHAs over the next 33 years. 13 A close encounter is defined as an approach within 0.2 Astronomical Units (AU). One AU is defined as the nominal distance from the center of the Earth to the center of the Sun: about 150 million kilometers, or 93 million miles. 0.2 AU is thus about 30 million kilometers or 19 million miles. In comparison, the diameter of the Earth is on the order of 8 thousand miles and the distance from the center of the Earth to the center of the Moon is about a quarter million miles.
The following information sources were used to prepare and update the above
essay. The hyperlinks are not necessarily still active today.
"Cretaceous-Tertiary extinction event," Wikipedia, as on 2011-OCT-30, at: http://en.wikipedia.org/
William K. Hartmann, "1908 Siberia Explosion," at: http://www.psi.edu/
Timothy Stenovec, "Asteroid 2005 YU55 To Narrowly Miss Earth," The Huffington Post, 2011-NOV-05 [Date in error on the Huffington Post web site], at: http://www.huffingtonpost.com/
"Fire from the sky: Meteors and Biblical Prophecy," at: http://www.angelfire.com/
Asteroid 1997 XF11 has its own web page at: http://ssd.jpl.nasa.gov/
David Whitehouse, "Space rock 'on collision course'," BBC News, 2002-JUL-24, at: http://news.bbc.co.uk/
Robin Lloyd, "Scientists reduce odds of earth-asteroid collision," CNN.com, 1999-JUL-28, at: http://www.cnn.com/TECH/space/9907/28/asteroid.newser/
"Asteroid information services," by the Space Mechanics Group of the Department of Mathematics, University of Pisa, Italy, at: http://newton.dm.unipi.it
Melosh & Collins, "Earth impact effects program," Department of Planetary Sciences, University of Arizona, at: http://www.lpl.arizona.edu/
"Phew! Asteroid's Passing Was A Cosmic Near-Miss," Associated Press, 2009-MAR-04, at: http://cbs2.com/
"Asteroid 'crime family' blamed in dinosaur wipeout," World Science, 2007-SEP-05, at: http://www.world-science.net/
Brian G. Marsden, "Press information sheet: One-mile-wide asteroid to pass close to Earth in 2028," Harvard-Smithsonian Center for Astrophysics, 1998-MAR-112, at: http://www.minorplanetcenter.net/
"Forthcoming close approaches to the Earth," IAU Minor Planet Center, updated continually, at: http://www.minorplanetcenter.net/
"Friday the 13th, 2029," NASA, 2005-MAY-13, at: http://science.nasa.gov/
Paul Chodas et al., "Radar Observations Refine the Future Motion of Asteroid 2004 MN4," NASA, 2005-FEB-03, at: http://neo.jpl.nasa.gov/
"Impact event," Wikipedia, as on 2013-FEB-22, at: http://en.wikipedia.org/
Copyright © 2011 & 2013 by Ontario Consultants on
Original posting: 2011-NOV-08
Latest update: 2013-FEB-23
Compiled by B.A. Robinson