Near Earth Objects
Introduction
Near Earth objects are basically asteroids as well as comets that come under the influence of gravitational forces of planets that are nearby hence allowing such objects to venture into earth’s neighborhood. In this text, I discuss different aspects of near earth objects.
Near earth objects: a discussion
The majority of near earth objects are in close proximity but research indicates that their gravitational force is negligible. The peripheries distance of most of the near earth objects is estimated to be not more than 1.3 AU and in this category, we have near earth instruments whose size makes it possible to track hem before they impact planet earth. According to Explore (2010), asteroid NEOs can be found within 0.99 and 1.3 astronomical unit orbits when their proximity to the sun is taken into consideration (Explore 2010).
Near earth asteroids are classified into different classes. It is important o note that when it comes to the classification, what mainly counts is the composition or size of the NEO. Those NEO that obit the sun fall under the classification of comets, asteroids and meteoroids. It can however be noted that while some asteroids can be taken to belong to the asteroid family, some debris can be left by comets in their orbit. As per May 2010 records, the number of discovered near earth comets was 84 while the number of near earth asteroids stood at close to 7000. Those NEOs that are believed to be potentially hazardous are stand at 1125.
It can be noted that over time, human beings have studied NEO with increasing interest. Destructive potential of NEO has been exhibited by the earth’s impact craters. This combined with other hazards associated with these objects is probably the main reason of the increasing attention towards he observance of the same by a wide range of professionals including but not in an way limited to the U.S defense department, geologists, astronomers as well as space engineers and biologists. It has been proved that the earth together with other planets is located within a cosmic collision pathway. The effects of a cosmic collision can perhaps be explained using the 1994 Jupiter/comet shoemaker-Levy crush that went a long way to prove that indeed, cosmic crushes are real. However, NEOs can be taken to be an area that is relatively untapped as far as the solar system future exploration is concerned. Perhaps the other reason that should make human beings concerned with Near Earth Objects is their untapped potential as sources of water, metals as well as other raw materials which can be utilized for a number of purposes.
When it comes to earth’s history, near earth Objects have had a lasting effect. Though NEOs have not had any impact or prominence in the modern times, as recently as 1908, the SiberianTunguskaRiver airburst as informed by a weak asteroid or comet entry. The Alvarez hypothesis and its subsequent acceptance especially with regard to the Cretaceous-Tertiary extinction, an event that was informed by an impact of a massive object, helped shed light into other impacts that had taken place before as well as probable impacts in future.
The Torino Impact Scale
According to David Morrison (2011), the Torino Impact Scale is designed with the sale purpose of the earth impact hazard categorization with regard to comets and asteroids that are newly discovered. It serves as a veritable tool of communication not only for astronomers but also for members of the pubic as well. As far as communication is concerned, the Torino Impact Scale makes the assessment of comets as well as asteroids proximity easier. When it comes to the importance of the Torino Impact Scale, Explore (2010) is of the opinion that on discovery of a comet or asteroid, its position in the near future, that is, days or years to come, is largely unknown. The uncertainty in this case comes about because the observations made on discovery of such objects are based on an orbital track that is largely short. Further, the precision of the measurement tools is limited. It is important to note that in this respect, the Torino scale comes about as a ‘richer scale’ of sorts.
Differences between a comet and an asteroid
When it comes to classification, both comets and asteroids are taken to be near-earth objects. When it comes to composition, it is important to note that asteroids and comets differ. While comets are made of compounds (carbon based), rock as well as ice; asteroids are made up of metal and rock. Further, when it comes to their formation, the formation of comets is believed to have been solar system (outer) while the formation of asteroids is thought to be in the solar system (inner). It is also important to note that in terms of size, an asteroid appears to be smaller as compared to a comet. An asteroid is also inactive while a comet is inactive. Also, while the orbits of comets seem to be quite elongated, the orbit of an asteroid appears to be more or less circular. However, the distinction between a comet and an asteroid cannot be said to be absolute in any way (Aero Space Guideline, 2010).
Shoemaker-Levy 9
The Shoemaker-Levy 9 was a comet that was engaged in a collision with Jupiter in the mid 90s. This according to scientists was the only (collision) extraterrestrial that was observed directly until then and for that reason I elicited allot o coverage from the media, both print and electronic. Indeed, thanks to the collision, astronomers from round the globe were able to gather more facts about Jupiter especially with regard to the important role it played as far as bringing down inner solar system space debris is concerned. This is one of the main reasons why the Shoemaker-Levy 9 is considered important.
Diversion of funds to study Near Earth Objects
In my opinion, the diversion of funds to study NEO is considerably important so as to chart impacts in future as well as understand the composition of near earth objects. It is important to note that though the likelihood of NEOs colliding with earth in a way that would bring about catastrophic outcomes is largely unlikely in the near future, the importance of observing the same cannot be overstated. Hence the allocation of funds to such projects is not only necessary but timely so as to minimize threats.
Conclusion
In conclusion, it may be noted that the interest of NEOs in the recent past has been increasing steadily. It is hoped that in the recent future, with the continued diversion of funds to study Near Earth Objects, more discoveries shall be made with regard to the nature and composition of NEOs.
References
Explore (2010). Space topics: Near earth objects. Retrieved from http://www.planetary.org/explore/topics/near_earth_objects/ on February 11, 2011
David Morrison (2011). Asteroid and Comet impact Hazards. Retrieved from http://impact.arc.nasa.gov/torino.cfm on February 11, 2011
Aero Space Guideline (2010) Differences between asteroids and comets. Retrieved from http://www.aerospaceguide.net/whatisanasteroid.html on February 11, 2011
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