NASA (National Aeronautics and Space Administration - An independent agency of the United States government responsible for aviation and spaceflight), ESA (European Space Agency) and other Space Agencies from other nations are now watching the skies to make sure we are not taken by surprise if another large asteroid heads our way. The project is called the Near Earth Objects Program.

Find more at http://neo.jpl.nasa.gov also http://www.esa.int/esaSC/index.html

سُوۡرَةُ القَمَر
بوَلَقَدۡ جَآءَهُم مِّنَ ٱلۡأَنۢبَآءِ مَا فِيهِ مُزۡدَجَرٌ (٤)
The Moon 54:4
And surely there hath come unto them news whereof the purport should deter,
سُوۡرَةُ القَمَر
اور ان کو ایسے حالات (سابقین) پہنچ چکے ہیں جن میں عبرت ہے (۴)


NEO has found that at least 2,500 asteroids exist in an orbit that could conceivably bring them into a collision course with Earth. Unfortunately, only 20% of them have been properly identified to date. Hopefully, we will find the other 80% before it is too late.

The Near Earth Objects Program has discovered several asteroids that have passed by Earth recently (fortunately without hitting us). One of them almost smacked into Earth in March 2004, missing us by only 3 Earth diameters (about 25,000 miles).

In 2029 (hopefully, we’ll all still be alive and well) another asteroid is going to pass even closer to Earth. In fact, its close encounter may swing it on a new trajectory around the sun that will give it a small chance of hitting Earth when we again meet up with it in 2036. It is about 280 meters or 1/6 mile wide, and is moving very fast. Its name is Apophis (also known as 2004 MN4).

Using binoculars on Earth, you should be able to see it pass by for real in 2029. If we are very unlucky, it will hit Earth in 2036, and everyone will know what that will be like!!! If it did, it most likely would smack into the ocean, creating a huge tidal wave (tsunami). Sweeping out from the impact site, it could drown thousands of miles of coastline.

سُوۡرَةُ الاٴنبیَاء
بَلۡ تَأۡتِيهِم بَغۡتَةً۬ فَتَبۡهَتُہُمۡ فَلَا يَسۡتَطِيعُونَ رَدَّهَا وَلَا هُمۡ يُنظَرُونَ (٤٠)
The Prophets 21:40
Nay, but it will come upon them unawares so that it will stupefy them, and they will be unable to repel it, neither will they be reprieved. (40)
سُوۡرَةُ الاٴنبیَاء
بلکہ قیامت ان پر ناگہاں آ واقع ہوگی۔ اور ان کے ہوش کھو دے گی۔ پھر نہ تو وہ اس کو ہٹا سکیں گے اور نہ ان کو مہلت دی جائے گی (۴۰)

Humans are not helpless when it comes to asteroids. It is possible that if one on a collision course with Earth was found soon enough, we could launch spacecraft that could nudge its course enough to cause it to miss an impact with Earth. However, we have no such technical capability yet.

Near-Earth Object Deflection Strategies
Strategies fall into two basic sets: destruction and delay.

Destruction concentrates on rendering the impactor harmless by fragmenting it and scattering the fragments so that they miss the Earth or burn up in the atmosphere. As will be shown, this does not always solve the problem, as sufficient amounts of material hitting the Earth at high speed can be devastating even if they are not collected together in a single body.

Delay exploits the fact that both the Earth and the impactor are in orbit. An impact occurs when both reach the same point in space at the same time, or more correctly when some point on Earth's surface intersects the impactor's orbit when the impactor arrives. Since the Earth is approximately 12,750 km in diameter and moves at approx. 30 km per second in its orbit, it travels a distance of one planetary diameter in about 425 seconds, or slightly over seven minutes. Delaying, or advancing the impactor's arrival by times of this magnitude can, depending on the exact geometry of the impact, cause it to miss the Earth. By the same token, the arrival time of the impactor must be known to this accuracy in order to forecast the impact at all, and to determine how to affect its velocity.

Nuclear weapons
One of the often proposed solutions is firing nuclear missiles at the oncoming asteroid to vaporize all or most of it. If not completely vaporized, the resulting reduction of mass from the blast combined with the radiation blast and rocket exhaust effect from ejecta could produce positive results. The largest problem with this solution is that if the asteroid breaks into fragments, any fragment larger than 35 m across would not burn up in the atmosphere and itself could impact Earth. Tracking of the thousands of fragments that could result would prove daunting.

Another proposed solution is to detonate a series of smaller nuclear devices alongside the asteroid, far enough away as not to fracture the object. Providing this was done far enough in advance, the relatively small forces from any number of nuclear blasts could be enough to alter the object's trajectory enough to avoid an impact. This is a form of nuclear pulse propulsion. In 1967, students at the Massachusetts Institute of Technology designed a system using nuclear explosions to prevent a hypothetical impact on Earth by the asteroid 1566 Icarus. This design study was later published as Project Icarus (MIT Press, 1968), which served as the inspiration for the 1979 film Meteor.

Kinetic Impact
An alternative means of deflecting an asteroid is to attempt to directly alter its momentum by sending a spacecraft to collide with the asteroid.

The European Space Agency is already studying preliminary design of a space mission able to demonstrate this futuristic technology. The mission, named Don Quijote, is the first real asteroid deflection mission ever designed.

In the case of 99942 Apophis it has been demonstrated by ESA's Advanced Concepts Team that deflection could be achieved by sending a simple spacecraft weighing less than one ton to impact against the asteroid. During a trade-off study one of the leading researchers argued that a strategy called 'kinetic impactor deflection' was more efficient than others.

Asteroid Gravitational Tractor
The major alternative to explosive deflection is to move the asteroid slowly over a period of time. Tiny constant thrust accumulates to deviate an object sufficiently from its predicted course. Edward T. Lu and Stanley G. Love have proposed using a large heavy unmanned spacecraft hovering over an asteroid to gravitationally pull the latter into a non-threatening orbit. The spacecraft and the asteroid mutually attract one another. If the spacecraft counters the force towards the asteroid by, e.g., an ion thruster, the net effect is that the asteroid is accelerated towards the spacecraft and thus slightly deflected from its orbit. While slow, this method has the advantage of working irrespective of the asteroid composition or spin rate rubble pile asteroids would be difficult or impossible to deflect by means of nuclear detonations while a pushing device would be hard or inefficient to mount on a fast rotating asteroid. A gravity tractor would likely have to spend several years beside the asteroid to be effective.

Use of Focused Solar Energy
NASA study of a solar sail. The sail would be 0.5 km wide.

H. Jay Melosh proposed to deflect an asteroid or comet by focusing solar energy onto its surface to create thrust from the resulting vaporization of material, or to amplify the Yarkovsky effect. Over a span of months or years enough solar radiation can be directed onto the object to deflect it.

Mass Driver
A mass driver is an (automated) system on the asteroid to eject material into space thus giving the object a slow steady push and decreasing its mass. A mass driver is designed to work as a very low Specific Impulse system, which in general uses a lot of propellant, but very little power.

The idea is that when using local material as propellant, the amount of propellant is not as important as the amount of power, which is likely to be limited.

A mass driver can impart a lot more momentum to an asteroid than a rocket carried there.

Conventional Rocket Motor
Attaching any spacecraft propulsion device would have a similar effect of giving a steady push, possibly forcing the asteroid onto a trajectory that takes it away from Earth. An in-space rocket engine that is capable of imparting an impulse of 1E6 m-sec (E.g. adding 1 km/sec to a 1 ton vehicle), will have a relatively small effect on a relatively small asteroid that weighs roughly a million times more.

Other Proposals
Wrapping the asteroid in a sheet of reflective plastic such as aluminized PET film, or dusting the object with titanium dioxide to alter its trajectory via radiation pressure.

Dusting the object with soot to alter its trajectory via the Yarkovsky effect.

Attaching a large enough solar sail directly to the object, thus using solar pressure to shift the object's orbit
Chapman, Durda & Gold's white paper calculates deflections using existing chemical rockets, delivered to the asteroid, then push it sideways, assuming sufficient fuel also delivered.

The late Eugene Shoemaker in 1996 proposed deflecting a potential impactor by releasing a cloud of steam in the path of the object, hopefully gently slowing it. Nick Szabo in 1990 sketched a similar idea, "cometary aerobraking", the targeting of a comet or ice construct at an asteroid, then vaporizing the ice with nuclear explosives to form a temporary atmosphere in the path of the asteroid.

Deflection technology concerns
Carl Sagan, in his book Pale Blue Dot, expressed concerns about deflection technology: that any method capable of deflecting impactors away from Earth could also be abused to divert non-threatening bodies toward the planet. Considering the history of genocidal political leaders and the possibility of the bureaucratic obscuring of any such project's true goals to most of its scientific participants, he judged the Earth at greater risk from a man-made impact than a natural one. Sagan instead suggested that deflection technology should only be developed in an actual emergency situation.

Analysis of the uncertainty involved in nuclear deflection shows that the ability to protect the planet does not imply the ability to target the planet. A nuclear bomb which changed an asteroid's velocity by 10 meters/second (plus or minus 20%) would be adequate to push it out of an earth-impacting orbit. However, if the uncertainty of the velocity change was more than a few percent, there would be no chance of directing the asteroid to a particular target.

Find more at http://en.wikipedia.org/wiki/Asteroid_deflection_strategies  also http://neo.jpl.nasa.gov

Now Read Carefully what Allah said in Quran…

سُوۡرَةُ إبراهیم
وَقَدۡ مَكَرُواْ مَڪۡرَهُمۡ وَعِندَ ٱللَّهِ مَڪۡرُهُمۡ وَإِن كَانَ مَڪۡرُهُمۡ لِتَزُولَ مِنۡهُ ٱلۡجِبَالُ (٤٦) فَلَا تَحۡسَبَنَّ ٱللَّهَ مُخۡلِفَ وَعۡدِهِۦ رُسُلَهُ ۥۤ‌ۗ إِنَّ ٱللَّهَ عَزِيزٌ۬ ذُو ٱنتِقَامٍ۬ (٤٧) يَوۡمَ تُبَدَّلُ ٱلۡأَرۡضُ غَيۡرَ ٱلۡأَرۡضِ وَٱلسَّمَـٰوَٲتُ‌ۖ وَبَرَزُواْ لِلَّهِ ٱلۡوَٲحِدِ ٱلۡقَهَّارِ (٤٨) وَتَرَى ٱلۡمُجۡرِمِينَ يَوۡمَٮِٕذٍ۬ مُّقَرَّنِينَ فِى ٱلۡأَصۡفَادِ (٤٩) سَرَابِيلُهُم مِّن قَطِرَانٍ۬ وَتَغۡشَىٰ وُجُوهَهُمُ ٱلنَّارُ (٥٠) لِيَجۡزِىَ ٱللَّهُ كُلَّ نَفۡسٍ۬ مَّا كَسَبَتۡ‌ۚ إِنَّ ٱللَّهَ سَرِيعُ ٱلۡحِسَابِ (٥١) هَـٰذَا بَلَـٰغٌ۬ لِّلنَّاسِ وَلِيُنذَرُواْ بِهِۦ وَلِيَعۡلَمُوٓاْ أَنَّمَا هُوَ إِلَـٰهٌ۬ وَٲحِدٌ۬ وَلِيَذَّكَّرَ أُوْلُواْ ٱلۡأَلۡبَـٰبِ (٥٢)
Ibrahim 14: 46-52
Verily they have plotted their plot, and their plot is with Allah, though their plot were such whereby the mountains should be moved. (46) So think not that Allah will fail to keep His promise to His messengers. Lo! Allah is Mighty, Able to Requite (the wrong). (47) On the day when the earth will be changed to other than the earth, and the heavens (also will be changed) and they will come forth unto Allah, the One, the Almighty, (48) Thou wilt see the guilty on that day linked together in chains, (49) Their raiment of pitch, and the Fire covering their faces, (50) That Allah may repay each soul what it hath earned. Lo! Allah is swift at reckoning. (51) This is a clear message for mankind in order that they may be warned thereby, and that they may know that He is only One God, and that men of understanding may take heed. (52)
سُوۡرَةُ إبراهیم
اور انہوں نے (بڑی بڑی) تدبیریں کیں اور ان کی (سب) تدبیریں خدا کے ہاں (لکھی ہوئی) ہیں گو وہ تدبیریں ایسی (غضب کی) تھیں کہ ان سے پہاڑ بھی ٹل جائیں (۴۶) تو ایسا خیال نہ کرنا کہ خدا نے جو اپنے پیغمبروں سے وعدہ کیا ہے اس کے خلاف کرے گا بےشک خدا زبردست (اور) بدلہ لینے والا ہے (۴۷) جس دن یہ زمین دوسری زمین سے بدل دی جائے گی اور آسمان بھی (بدل دیئے جائیں گے) اور سب لوگ خدائے یگانہ وزبردست کے سامنے نکل کھڑے ہوں گے (۴۸) اور اس دن تم گنہگاروں کو دیکھو گے کہ زنجیروں میں جکڑے ہوئے ہیں (۴۹) ان کے کرتے گندھک کے ہوں گے اور ان کے مونہوں کو آگ لپیٹ رہی ہوگی (۵۰) یہ اس لیے کہ خدا ہر شخص کو اس کے اعمال کا بدلہ دے۔ بےشک خدا جلد حساب لینے والا ہے (۵۱) یہ قرآن لوگوں کے نام (خدا کا پیغام) ہے تاکہ ان کو اس سے ڈرایا جائے اور تاکہ وہ جان لیں کہ وہی اکیلا معبود ہے اور تاکہ اہل عقل نصیحت پکڑیں (۵۲)

سُوۡرَةُ المُلکِ
ءَأَمِنتُم مَّن فِى ٱلسَّمَآءِ أَن يَخۡسِفَ بِكُمُ ٱلۡأَرۡضَ فَإِذَا هِىَ تَمُورُ (١٦) أَمۡ أَمِنتُم مَّن فِى ٱلسَّمَآءِ أَن يُرۡسِلَ عَلَيۡكُمۡ حَاصِبً۬ا‌ۖ فَسَتَعۡلَمُونَ كَيۡفَ نَذِيرِ (١٧)
Al-Mulk 67:16-17
Have ye taken security from Him Who is in the heaven that He will not cause the earth to swallow you when lo! it is convulsed? (16) Or have ye taken security from Him Who is in the heaven that He will not let loose on you a hurricane? But ye shall know the manner of My warning. (17)
سُوۡرَةُ المُلکِ
کیا تم اس سے جو آسمان میں ہے بےخوف ہو کہ تم کو زمین میں دھنسا دے اور وہ اس وقت حرکت کرنے لگے (۱۶) کیا تم اس سے جو آسمان میں ہے نڈر ہو کہ تم پر کنکر بھری ہوا چھوڑ دے۔ سو تم عنقریب جان لو گے کہ میرا ڈرانا کیسا ہے (۱۷)


Watch a video clip of an NEO Collision Impact on Earth