Asteroid DD45 missed earth by only 76,800 km - How close is this, and was it close enough to worry?
Next object is anticipated to arrive in the period of 2029 - 2037, when a major Asteroid called Apophis is prognosed to become a near earth object.
Prize money is promised for those who can assist tracking this next major object to threaten the earth.
Asteroid DD45 was observed on February 27th 2009 for the first time, never seen before. Only 4 days later it missed earth by a distance close to our geostationary satellites. It almost came in close to the range where we have placed lots of our critical communications and observation satellites, for both civilian and military purposes.
The geostationary orbit, called the Clarke Orbit. (Named after Arthur C. Clarke) is the part of space at 35,786 km above sea level, in the plane of the equator, where near-geostationary orbits may be implemented. The Clarke Orbit is about 265,000 km long.
Geostationary orbits are useful to have a satellite to appear stationary with respect to a fixed point on the rotating Earth. As a result, an antenna can point in a fixed direction and maintain a link with the satellite. The satellite orbits in the direction of the Earth's rotation, at an altitude of 35,786 km above sea level. This altitude is significant because it produces an orbital period equal to the Earth's period of rotation, known as the sidereal day.
Asteroid DD45 missed earth at a distance of 76,800 km at March 2nd 2009, only twice the distance from earth as the geostationary orbits.
The distance from earth which DD45 passed the earth is only 20% of the distance from earth to the moon, and is actually one of the closest near earth objects missed the earth in the later years.
The diameter of DD-45 is estimated to be in the range of 21-47 meters, so its classified as a minor object. The impact should an object could cause if impacted the earth could be compared to what we saw in Siberia, Russia a few years back (June 30th 1908 in Tunguska area in Siberia in Russia). This impact caused 80 million trees to be blown over in an area of around 2150 square kilometers, and the impact would have wiped out a large city with no problem. To illustrate the area, it is equivalent to the area of El Salvador, Latin America's landmass. This means if Asteroid DD45 had hit the earth, it would not have created a global catastrophe, but it would have created regional impact, and dependant upon where it would have hit, it could have caused a major disaster with loss of human life.
Observers saw this object only 4 days before it passed earth with a fraction away from our critical satellite systems. This was due to the size of the object it was told, and the reports tells us that NASA was not the first to see it, as it was observed by independent observers first, which reported it to NASA. This gives us several questions we need answers to. Do we have an effective warning system for Near Earth Objects? Is the threshold to high or technology limited for observed objects? That means objects have to be a certain size before detected or followed. Is it enough to have only NASA following these objects, and to detect new ones, or should we call for an international body to take responsibility for this task, as it can involve all of us?
Imagine this object steered into our atmosphere and made an impact in urban areas, or densely populated countries, like El Salvador f.inst. Human disaster would be great, maybe millions would be dead and injured by such an event. What kind of counter measures do we have for such objects, and what kind of alert systems are available on international basis?
Ok, so some say, we do not have many objects hitting the earth, and most of them impact in deserted areas of the globe. The last ones hitting the earth were in Sudan, Norway and Sweden. However, all these three events the last few years were not that far from densely populated areas though. How long do we want to count on historic statistics that tells us that so far no human has been killed by an asteroid?
I bet the dinosaurs did not see it coming either, as they had never been struck by any asteroid before this event happened 65 million years ago.
NASA has mapped out 10 asteroids missed the earth so far in 2009, none of these objects were estimated to be above 710 meters in diameter. The closest was DD45 with 76.800 km from earth, and rest in excess of 2 million km away from the earth. So far, so good. However, we know from history that the earth has been hit by medium to small objects, with the last major one in 1908 in Russia, as mentioned above. We got a warning shot by DD45, similar in size, missing us this time.
The next big threat is the asteroid is called Apophis, and was discovered some years ago. In the year of 2029, it will pass the earth at a distance were it can hit communication satellites orbiting the earth, while in the year of 2036 it will come even closer that that. The Apophis is around 600 meters in diameter. As of April 16, 2008, the impact probability for April13, 2036, is calculated as 1 in 45,000. An additional impact date in 2037 is also identified; the impact probability for that encounter was calculated as 1 in 12.3 million.
On Friday, April 13, 2029, Apophis will pass Earth within the orbits of geosynchronous communication satellites. It will return for another close Earth approach in 2036
Many scientists agree that Apophis warrants closer scrutiny and, to that end, in February 2008 the Planetary Society awarded $50,000 in prize money to companies and students who submitted designs for space probes that would put a tracking device on or near the asteroid.
The Apophis, named 2004 MN4 or 99942 in the astrophysical world, is not on the list of official asteroids publicized on NASA web site, as the cut off date for objects in that list is set to the year 2031, we do not know the reason for this.
The approach path of impact possibilities in 2036 for the Apophis straddles along a line starting from Kazakhstan, into south eastern part of Russia, then after into the Pacific ocean before crossing over the central American region and then onwards towards the west over the Atlantic ocean towards the coast of Africa, more specific the southern part of Morroco.
Nico Marquardt, a 13-year-old from Germany, was reported to have produced a collision estimate of 1 in 450 (100 times greater than NASA's calculation) in April 2008, by factoring in the possibility of Apophis running into one or more of the geosynchronous satellites orbiting Earth during its flyby on April 13, 2029. This estimate was allegedly then confirmed by ESA and NASA but in an official statement, NASA denied having contact with Marquardt. The release went on to explain that since the angle of Apophis's approach to the Earth's equator means the asteroid will not travel through the belt of existing equatorial geosynchronous satellites and the extremely small size of satellites relative to the size of their orbits means that there is currently no risk of collision; and the effect on Apophis' orbit of any such impact would be insignificant.
On April 16, 2008, NASA News Release 08-103 reaffirmed that its estimation of a 1 in 45,000 chance of impact in 2036 remains valid.
We still have to have in mind that the globe has lots of intelligent people that can assist in the matter of following these objects coming at earth with a varying distance. This should call for an international task force with the main objective to only follow these objects and assess the risk for hitting terrestrial and space infrastructure mankind has put up.
We have become far to dependent upon infrastructure that is electronically based both on earth and in close space around us to neglect the fact that the safety of human being on earth demands not only observations, but potent counter measures and strategies for how to deal with the danger once it is alerted to us.
Who will take the responsibility if an object like Apophis makes a likelihood of approaching the earth in 2036. Are there any international bodies to take care of the practicalities, economics and technology to be implemented once this event potentially occurs? Can we trust that one technical group of experts will give us the total truth about events to come, and foremost of all, are they capable of giving us the proper prognosis's and alerts we need to be prepared for an event to happen?
He has a background as civil engineer and geoscientist. He has worked mainly within the oil and gas industry from the mid 1980s. He has written a few fictional novels as well as being the author of some professional litterature within oil and gas sector, he is now an editor of some web sites.
