Our beloved planet, the Earth, is only life sustaining planet in the solar system. However, life on earth has always been under tremendous threats from different natural disasters. These disasters not only emanate from the surface and subsurface of earth but it is well known that the interplanetary space around earth is littered with dust and materials from the creation of the solar system.Among these objects, rocky metallic asteroids and comets, produced during the formation of planets, move with ferocious speed around the Sun. The comets and asteroids move in earth cloud in Kuiper beltand between Jupiter and Mars, respectively. But in some cases, due to the collision they change their paths and may move towards earth. Although, the earth is shielded by different layers of the atmosphere which vaporizes most of the asteroids but larger objects may survive the atmosphere and strike the earth. We, the humans, work routinely in our daily life, unaware of the fact that in the far reaches of space there are potential threats from these asteroids to our beloved planet.

Fig.1 An artist’s view of asteroid moving towards earth.

Recently, a similar kind of meteoroid fell in the Sindh province of Pakistan. The impact region was Ladki near Mithi and eyewitnesses observed a 45 degrees angle of striking the earth. The Metroid turned extremely bright like sunlight and exploded after striking the earth with noise. The meteoroid was recovered and weighed around 100gram meteorite. However, it is presumed that no such prior information was available about the possible strike of the object and subsequent safety of the impacted area and the people.

These objects which strikes the earth areknown as near earth Objects (NEOs). These NEOs every now and then strike the earth.Scientists believe that several NEOs have struck the earth in the past and every likelihood these numbers would be increased in future, due to many satellites, spacecrafts and their junks. Every time, a crucial impact affect the 80% life on the planet. These strikes some time bring enormous changes in the environment of the planet and are normallyconsidered beneficial. It is believed,65 million years ago, an asteroid of a size of small city struck in Sylvania and wiped away the dinosaurs from the planet.Another strike in June 1908 in Siberia was noticed when an object of size like a football ground struck and exploded before striking the earth. The explosiondestroyed 80 million trees in the forest where asteroid exploded. The energy produced due to the explosion was around 15Megaton of TNT (1TNT =4.184GJoules). Luckily, because it was in a remote area, no body died. However, according to the famous scientist Neil Tyson, if that asteroid had hit few hours later, it would have hit the Europe and millions of people would have died.

Are We Safe Enough?

Scientists believe,one of these kinds of strike caused emergence of humans on the earth. If that strike had not occurred, we the humans would have not been here on earth.But the main concern of scientific world is, the way asteroid wiped away the dinosaurs from the planet, may vanish the mankind as well, from the planet. One of the most worrying kind of asteroids for scientists is, Apophis. It is a 270 meters long asteroid, discovered in 2004. According to the scientist, Appophis will come closer than our communication satellites in April 2029. It is believed that owing to its size, in some areas it would be seen with the naked eye.

Another worry is, if Apophis passes the earth something like 18000miles, it may be attracted by a gravitational key hole of the earth which would change its path. Depending on its mechanical nature, it could experience shape or spin-state alteration due to tidal forces caused by Earth’s gravity field.  If that happens, after 7 years it will hit the earth. Although, having very low probability, scientists have managed to locate the possible regions of strike for Apophis in 2036. The deadly thing, is if apophis strikes in Pacific Ocean at the coast of California, it would produce one million mega ton of TNT. This would generate a crater of 5mile wide and 9000ft deep in the ocean, resulting in Tsunami. The power potential impacts yield tremendous energy, billions of times that a nuclear bomb.

 

Fig. 2A perspective of Scientists about the sequential events for a possible asteroid strike in 2036

How to Protect?

In recent times, more awareness has been developed among the key stake holders who believe that these threats are worth investigating. Recently, USA parliament asked NASA to track all the near earth objects greater than 500ft in diameter, which have potential threats to hit the earth.The famous scientist RusselSchweickratappeared in front of Congress to request the formation of government based agency for investigation of the potential threats to the common people of the United States. He convinced the authorities that the process of tracking of these objects is like surveillance. More time you spend on the activities of asteroids, the more idea is obtained about their velocity, behavior and orbit. Based on the data, a probabilistic analysis can be made about these objects striking the earth. The efforts were made by NASA to discover near earth asteroids and so far NASA has found around two dozen objects like that so far. However, the most worrying thing,is there are several other asteroids who haven’t discovered so far due to limitation of the technology or the effort.

The scientists believe that these kinds of impact would happen in future and if we have to survive and don’t want to be like dinosaurs, our future is inour hand.The technology is matured enough to track these kind of threats and changes can be made in the local solar system if any threat moves towards the earth. We can change our local solar system and our survival can be enhanced.

The technology is in the form that these kinds of potential threats may be destroyed or may be forced to alter their path while striking with rockets or missiles. One option which is being considered is sending the warheads on the asteroid and blow up the object. However, it is considered that the debris due to explosion will be more destructive than the object itself. In addition, nuclear radiation would reach us. Another option, which got the consensus from mostof the stake holders, is changing the path of the asteroid through some means.
The recent strike of the space junk in Pakistan is also a kick off call for all of us. Although, we are continuously struggling with hurricanes and earthquakes and still experiencing impacts on our weak economy, the disasters from near earth objects yet cannot be ignored.It is obvious that unless investigated and observed continuously with cutting edge technology, the safety cannot be guaranteed. There are some institutes and societies working independently to observe the planets and solar system, yet there is no such body in Pakistan which actually keep records of near earth objects. In addition, there is very little knowledge among the social societies about the importance of these kinds of events which take place every now and then and we consider “awareness is a real blessing” for the problems, we feel powerless to control.

References

http://www.guardian.co.uk/science/2005/dec/07/spaceexploration.research

http://neo.jpl.nasa.gov/apophis/

http://www.deepastronomy.com/apophis-asteroid-could-hit-earth.html

http://www.universetoday.com/13749/how-big-is-apophis/#ixzz2AsdVt1mp

About the Authors

Dr. Muhammad Kashif Khan holds PhD in Materials Engineering from UK and currently working as Postdoctoral Research Associate in China. Jawed Khan is a fresh Electronics Engineering graduate and has interests in Space Sciences.

Dr. Muhammad Kashif Khan & Jawed Khan

Email: kashoo@engineer.com