Space Rocks Can Be Dangerous The U.S. Government has instituted a program at NASA called Near Earth Objects Program or NEO. NASA has installed the Sentry automatic impact monitoring system. The Sentry system took 2 years to create and is a highly automated system for continuous updates of the orbits, future close approaches and impact probabilities for all NEOs. NEOs are usually meteors or pieces of comets. The Sentry system was built to be complementary to the NEODyS CLOMON impact monitoring system operated in Pisa, Italy. Personnel from both systems are constantly communicating with each other and cross checking each other's results. They provide constructive feedback to continuously improve the efficiency and accuracy of both systems. The Deep Impact space mission crashed a space vehicle into a comet to provide information for engineers on destroying NEOs. The energy of the crash generated the equivalent of 4.5 tons of TNT. The most important part of this mission was to see if we can hit a 3.5 mile wide area from millions of miles away. British scientists are calling for something to be done to protect the earth from hits by objects from space. The Task Force on Near Earth Objects, which was appointed years ago by science minister Lord Sainsbury, had produced a report which said the threat of an asteroid hit is real and the government should take action to prevent it. The report, wants an international effort to develop an asteroid early warning system involving British telescopes. Scientists agree the elements needed for a successful plan to protect the earth from NEOs are: At the present time 200 meter or less NEOs are not detectable and bigger telescopes are needed, which are being constructed. At a meeting at NASA on November 30, 2018 it was said the chance of earth being hit by an asteroid in 2027 is 96 percent. So how can we protect ourselves if we spot an asteroid heading for us? The only program I know about is the one where we send up a rocket with an explosive and hope it is powerful enough to deflect the object. We do have some very accurate rockets that can be fitted with nuclear warheads. This presents us with another problem however. Should we try and shatter an object? If we did have a warhead powerful enough to shatter an object heading for earth, we would have to hit it just right to make sure the pieces didn't hit us with a shot gun effect. which might be worse than the initial hit. We would have to hit the object relatively far out if it was large, to try and change its trajectory. At the right distance a couple of degrees could make all the difference. The US and Russia have proposed launching a mirrored aluminum sail that would track the asteroid's orbit. Sunlight would be focused to 2000 degrees centigrade and would be reflected onto the asteroid at a certain point. This would vaporize rock and ice causing a vapor jet which would hopefully deflect the asteroid from hitting the earth. The US military has been experimenting with lasers for several decades now and although the results are secret, we might have a laser powerful enough to move or shatter an object, but this is only speculation. Laser beams defocus when aimed through the atmosphere which makes using them from earth almost impossible. Suggestions have been put forth that we develop a fleet of space vehicles all built around the same body to save on cost and if a NEO would threaten the earth, we could launch many of them at the same time, thus giving us a better chance of either blowing up or nudging the NEO. We suffered a near miss on October 30, 2000 when a 600 meter NEA named Toutatis came within less than 1/2 degree from earth. NASA remained silent. There is a big problem with detecting objects which are approaching the earth and the problem is we don’t always detect them. Many times, we have been surprised by one in as little time as the day before it zooms past the earth. The buzz word which is being used when we are talking about asteroids and meteors heading our way is Planetary Defense and there is a Planetary Defense Coordination Office at NASA. NASA has said they have a cut off point when it comes to the size of objects they worry about and it is 460 feet. They chose this size, because this size and less will only produce regional effects if there is an impact, there is no chance of them being harmful to the entire planet. I wonder about this, because if one of this size hits us and has some unknown material in it, who is to say that would not do a lot more damage than expected. Here is a scary thought, two-thirds of the near earth objects which are 460 feet in diameter or larger are yet to be found. There is no doubt we need an improved system for detecting objects and we also need to figure out how would we stop them or at least steer them off course. If one was large enough we might be faced with the fact we could do nothing about it. I remember reading a science fiction story once where a huge planet sized object was heading toward the earth and the scientists figured out how to move the earth. This was only a story of course but there has been a lot of talk about building an engine for a spacecraft which could bend space. Perhaps if we ever succeeded in building something like this it might be able to bend the space in front of an incoming object to send it somewhere else. One problem NASA has is optical telescopes can only operate at night and even then, if it is not clear they may not be able to spot some objects. Some believe we should be using radar to detect objects heading our way, but they don’t understand the problem which is we do not have radar which is powerful enough to sweep the heavens to look for these objects. It would also be very helpful if we had some type of detection which operated much faster than the speed of light so we could detect these objects much faster. Detecting objects heading our way is difficult and destroying or moving them even more difficult. Unless we can figure out a way to vaporize these objects the only thing left for us to do with our current technology is try and move them off course.
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