Asteroid & Meteors

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Description or Situation

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Overview

Just like a scenario out of a doomsday film exists the real potential for an asteroid or meteor to strike the surface of planet Earth. It is evident and concluded that these sorts of events occur through out the history and existence of most all planetary spheres. Objects and debris are abundant in space and typically present more of a threat than what is clearly understood. Impact on planets and moons are more evident on adjacent planetary objects near Earth as can be seen with telescopes and NASA imaging data. Most neighboring planets around Earth have been struck a number of times by fast moving objects from space and have the scars to prove it. Earth is a unique planet constructed with an atmosphere that has a few layers of protection around it known as an atmosphere. Small  objects hurled in from space are often deflected or burned up before they can cause significant damage to this world. Most inhabitants of planet Earth have very little or no clue as to how many times this sort of minor event occurs. It is the larger events that present a real concern for life here on Earth. These larger events are said to be extinction level events, (ELE). A situation that causes all life to perish. Occurrences on Earth are historically cyclic and inevitable. They have happened in the past and will happen in the future. Is it possible for all life to be destroyed resulting from an impact of reasonable size  hurling into Earth from deep space or is this simply science fiction at it's best?

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What is an asteroid or meteor?

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Asteroid

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Asteroids are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids. These terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet. As minor planets in the outer Solar System were discovered and found to have volatile-based surfaces that resemble those of comets, they were often distinguished from asteroids of the asteroid belt. In this article, the term "asteroid" is restricted to the minor planets of the inner Solar System or co-orbital with Jupiter.

There are millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets. The large majority of known asteroids orbit in the asteroid belt between the orbits of Mars and Jupiter, or are co-orbital with Jupiter (the Jupiter Trojans). However, other orbital families exist with significant populations, including the near-Earth asteroids. Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, S-type, and M-type. These were named after and are generally identified with carbon-rich, stony, and metallic compositions, respectively.

Only one asteroid, 4 Vesta, which has a relatively reflective surface, is normally visible to the naked eye, and this only in very dark skies when it is favorably positioned. Rarely, small asteroids passing close to Earth may be visible to the naked eye for a short time. As of September 2013, the Minor Planet Center had data on more than one million objects in the inner and outer Solar System, of which 625,000 had enough information to be given numbered designations. [Source] [Additional Source] [Additional Source]

 

A meteoroid is a small rocky or metallic body traveling through space. Meteoroids are significantly smaller than asteroids, and range in size from small grains to 1 meter-wide objects. Objects smaller than this are classified as micro-meteoroids or space dust. Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.

When a meteoroid, comet or asteroid enters the Earth's atmosphere at a speed typically in excess of 20 km/s (72,000 km/h; 45,000 mph), aerodynamic heating produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor, or colloquially a "shooting star" or "falling star". A series of many meteors appearing seconds or minutes apart, and appearing to originate from the same fixed point in the sky, is called a meteor shower. If a meteor withstands ablation from its atmospheric entry and impacts with the ground, then it is called a meteorite.

Around 15,000 tonnes of meteoroids, micro-meteoroids and different forms of space dust enter Earth's atmosphere each year.

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What are the effects from an impact?

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An impact event is a collision between celestial objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal impact. When large objects impact terrestrial planets like the Earth, there can be significant physical and ionospheric consequences, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant land forms on many of the Solar System 's solid objects and present the strongest empirical evidence for their frequency and scale.

Impact events appear to have played a significant role in the evolution of the Solar System since its formation. Major impact events have significantly shaped Earth's history, have been implicated in the formation of the Earth–Moon system, the evolutionary history of life, the origin of water on Earth and several mass extinctions. Notable impact events include the Chicxulub impact, 66 million years ago, believed to be the cause of the Cretaceous–Paleogene extinction event.

Throughout recorded history, hundreds of Earth impacts (and exploding bolides) have been reported, with some occurrences causing deaths, injuries, property damage or other significant localized consequences. One of the best-known recorded impacts in modern times was the Tunguska event, which occurred in Siberia, Russia, in 1908. The 2013 Chelyabinsk meteor event is the only known such event to result in a large number of injuries, and the Chelyabinsk meteor is the largest recorded object to have encountered the Earth since the Tunguska event.

The most notable non-terrestrial event is the Comet Shoemaker–Levy 9 impact, which provided the first direct observation of an extraterrestrial collision of Solar System objects, when the comet broke apart and collided with Jupiter in July 1994. Most of the observed extra-solar impacts are the slow collision of galaxies; however, in 2014, one of the first massive terrestrial impacts observed was detected around the star NGC 2547 ID8 by NASA's Spitzer space telescope and confirmed by ground observations. Impact events have been a plot and background element in science fiction. [Source] [Additional Source] [Additional Source]

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What are the chances of a strike to planet Earth by an asteroid or meteor?

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The chance of a city-killing asteroid striking Earth is higher than scientists previously believed, a non-profit group building an asteroid-hunting telescope said on Tuesday. A global network that listens for nuclear weapons detonations detected 26 asteroids that exploded in Earth's atmosphere from 2000 to 2013, data collected by the Comprehensive Nuclear Test Ban Treaty Organization shows. The explosions include the February 15, 2013, impact over Chelyabinsk, Russia, which left more than 1,000 people injured by flying glass and debris.

"There is a popular misconception that asteroid impacts are extraordinarily rare ... that's incorrect," said former astronaut Ed Lu, who now heads the California-based B612 Foundation. The foundation on Tuesday released a video visualization of the asteroid strikes in an attempt to raise public awareness of the threat. Asteroids as small as about 131 feet - less than half the size of an American football field - have the potential to level a city, Lu told reporters on a conference call, "Picture a large apartment building - moving at Mach 50," Lu said. Mach 50 is 50 times the speed of sound, or roughly 38,000 mph.

NASA already has a program in place that tracks asteroids larger than 0.65 mile. An object of this size, roughly equivalent to a small mountain, would have global consequences if it struck Earth. An asteroid about 6 miles in diameter hit Earth some 65 million years ago, triggering climate changes that are believed to have caused the dinosaurs - and most other life on Earth at the time - to die off. "Chelyabinsk taught us that asteroids of even 20-meter (66-foot) size can have substantial effect," Lu said. City-killer asteroids are forecast to strike about once every 100 years, but the prediction is not based on hard evidence. B612 intends to address that issue with a privately funded, infrared space telescope called Sentinel that will be tasked to find potentially dangerous asteroids near Earth. The telescope, which will cost about $250 million, is targeted for launch in 2018. B612 takes its name from the fictional planet in the book "The Little Prince," by French author and aviator Antoine de Saint-Exupery. [Source]

The video can be seen on the B612 Foundation website b612foundation.org/

 

Videos:

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Additional videos: [Video 2] [Video 3] [Video 4] [Video 5]

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  Find  "solutions to asteroids & meteor strike" 

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References:

https://en.wikipedia.org/wiki/Asteroid

http://www.space.com/51-asteroids-formation-discovery-and-exploration.html

http://www.livescience.com/27183-asteroid-meteorite-meteor-meteoroid.html

 https://en.wikipedia.org/wiki/Impact_event

http://www.ucmp.berkeley.edu/education/dynamic/session5/sess5_asteroid.htm

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