Near Earth Objects

THE NEAR EARTH OBJECTS
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Table of Contents
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1. Introduction  PAGEREF _Toc351294045 \h
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2.0 The categories of NEOs  PAGEREF _Toc351294046 \h
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3.0 Currently identified Near Earth Objects  PAGEREF _Toc351294047 \h
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3.1 C/1996 B2 Hyatuke  PAGEREF _Toc351294048 \h
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3.2 4179 Toutatis  PAGEREF _Toc351294049 \h
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4.0 NEOs that have recently collided with planet earth  PAGEREF _Toc351294050 \h
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4.1 The Russian meteorite  PAGEREF _Toc351294051 \h
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4.2 The Tunguska meteorite of 1908  PAGEREF _Toc351294052 \h
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5.0 The scientific investigations of the future NEOs  PAGEREF _Toc351294053 \h
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5.1 NEOSSat  PAGEREF _Toc351294054 \h
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5.2 OSIRIS-Rex  PAGEREF _Toc351294055 \h
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6.0 Conclusion  PAGEREF _Toc351294056 \h
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7.0 References  PAGEREF _Toc351294057 \h
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1. Introduction
The near earth objects refers to as the solar system elements or objects such as comets and asteroids nudged by the attraction of the gravitational forces of the planets close to these objects causing them to deviate from their orbits and enter the planet’s atmosphere. Comets are mostly composed of ice and dust particles and are mostly found on the outer and cold part of the solar system. On the other hand, asteroids are composed of hard rocky materials and mostly found on the inner and hotter parts of the solar system that is to say between the mars and Jupiter orbits.
Over the years scientists have developed interest on the near earth objects (NEOs) largely because of their unchanged remnants in the solar system formation that has taken place in over four million years. It is evident from the scientific research and observation that the outer planets of the solar system such as Saturn, Jupiter, Neptune and Uranus, were formed from the agglomeration of millions of the NEOs such as comets and asteroids and that the meteors are the left remains (Jenniskens, World Space Congress, COSPAR general assembly, & World Space Congress. 2004). Just like the outer planets, the inner planets are a product of agglomeration that leads to the unattached pieces that are the asteroids.
These NEOs are a concern to the life of the inhabitants of the planet earth in that their presence may be unwelcomed. On their landing on earth they cause effects that are life threatening. This has made scientist as well as scientific organizations to develop interest on the NEOs and the possible ways of detecting their presence. Therefore, herein is the examination of the current NEOs as well as the past occurrences, their effects on life on planet earth and possible means of detecting and monitoring NEOs.
2.0 The categories of NEOs
Despite the fact that the identification of the NEOs is difficult, there have been success cases on identifying the NEOs and their various orbits. Scientists have gone further to identify their sizes speed along their orbits and their weight. Commonly used are the ground-based surveys for the efficient identification and detection of the NEOs. Large telescopes with a high magnifying power are used to identify the objects their diameters and their respective orbits. Such a telescope as the LSST is required in order to detect, identify, disseminate the results and determine the orbits and provide them to the interested societies on time. The scientific observations of the sky have been able to identify various NEOs as shown in figure one below (Greeley, 2012).
NEOs are categorized into two categories: the near earth comets (NECs) and the near earth asteroids (NEAs). The NEOs are restricted in order to include the short period comets (this is to say the comets with the orbital period of less than two hundred years. Asteroids on the other hand, are the NEOs are the majority. The asteroids are further categorized into various groups. This is according to the perihelion distance of the NEA denoted by q, the aphelion distance of the object denoted by Q and the object’s semi-major axes that is denoted by a. this is as indicated in the table below. (NASA Website).
Table  SEQ Table \* ARABIC 1 NEOs categories,
categorydescriptionNECsNear Earth CometsNEAsNear Earth AsteroidsAtirasNEAs with orbits contained entirely on earth’s orbitAtensNEAs crossing earth whose semi-major axes are smaller than that of the earthapollosNEAs crossing earth whose semi-major axes is larger than that of earthAmorsNEAs approaching earth having orbits that are exterior to earth’s but having orbits interior of mars’PHAsPotentially Harzadous NEAs with minimum orbit Intersection Diameter (MOID) with the earth as 0.05 AU or less, the absolute magnitude (H) is approximately 22.0 or it can be brighter
3.0 Currently identified Near Earth Objects
NEOs are termed as potentially hazardous when they have an orbit bringing it close to that of the planet earth currently and in the future. Further, the object should have a magnitude bright to the extent that it is large enough to cause wide scale damage in case of collision with planet earth. Therefore, PHA (Potentially Hazardous Asteroids) can be defined depending on the parameters measuring the object’s possibility of threatening approaches to planet earth. Scientific observations and calculations indicate that asteroids with MOID (minimum orbit intersection distance) of about 0.05 AU accompanied by a magnitude of 22.0 are classified as PHAs. The fact that the objects are considered potentially hazardous does not necessarily mean that the object will collide with the planet earth but it indicates that there is a possibility of such a danger. There are approximately one thousand three hundred identified asteroids posing threat to planet earth (Yeomans, 2013).
3.1 C/1996 B2 Hyatuke
One of the potential hazardous NEOs is the C/1996 B2 Hyatuke. This comet passed near the planet earth in the year 1996. Its aphelion distance was approximately 0.10 AU. The comet was three kilometers large. This object would threaten the safety of planet earth. In case of its collision with the planet it would cause widespread damage and in case it landed in the ocean it could have caused a tsunami.
3.2 4179 Toutatis
The other hazardous NEO is the 4179 Toutatis which is classified as an Apollo. It has a chaotic orbit with a resonance of 1:4. It has also made significant approaches towards the planet earth. Despite the fact that this object is classified as a potentially hazardous, its chances of colliding with earth are minute. T...