Asteroid Impact in 2182?
"The total impact probability of asteroid '(101955) 1999 RQ36' can be estimated in 0.00092 –approximately one-in-a-thousand chance- but what is most surprising is that over half of this chance (0.00054) corresponds to 2182," explains María Eugenia Sansaturio, co-author of the study and researcher at the Universidad de Valladolid (UVA).
The research also involved scientists from the University of Pisa (Italy), the Jet Propulsion Laboratory (USA) and INAF-IASF-Rome (Italy).
A 560-meter diameter asteroid could be highly destructive to life on Earth, no matter where it hit. The Tunguska event, a huge explosion that flattened thousands of square miles of Siberian forest in 1908, is estimated to have been caused by an object 40 to 70 meters in diameter. The asteroid in this study is about ten times that size.
Scientists who study the effects of impacts say an asteroid more than a kilometer in size (>1,000 meters) could cause nuclear winter conditions on Earth. The asteroid that is blamed for the extinction of the dinosaurs is estimated to have been 10 kilometers in diameter.
Scientists have estimated and monitored the potential impacts for this asteroid through the year 2200 by means of two mathematical models -- the Monte Carlo Method and a line of variation sampling. The researchers searched the so-called Virtual Impactors (VIs), sets of statistical uncertainty of impactors leading to collisions with the Earth on different dates of the twenty-second century.
The orbit of the asteroid is well determined thanks to 290 optical observations and 13 radar measurements, but there is a significant "orbital uncertainty" because, besides gravity, its path is influenced by the Yarkovsky effect. Such disturbance slightly modifies the orbits of the solar system's small objects because, when rotating, the asteroids radiate from one side the heat they absorb from the Sun through to the other side. The gentle effect of this heat radiation can cause the path of an asteroid to shift over long periods of time.
"The consequence of this complex dynamic is not just the likelihood of a comparatively large impact, but also that a realistic deflection procedure (path deviation) could only be made before the impact in 2080, and more easily, before 2060," says Sansaturio.
The scientist concludes: "If this object had been discovered after 2080, the deflection would require a technology that is not currently available. Therefore, this example suggests that impact monitoring, which up to date does not cover more than 80 or 100 years, may need to encompass more than one century. Thus, the efforts to deviate this type of objects could be conducted with moderate resources, from a technological and financial point of view."