عزيزي أو عزيزتي الأناكوندا... ( اسم مخيف :D )
ما تحدثت عنه هو الجرم XF11، وسيمر غي التاريخ المذكور قريباً جداً من الأرض... بل أقرب من القمر...
وقد رأيناه سايقاً في جنوب فرنسا في السماء لليالٍ عام 1997...
ولكن على العكس تماماً، فاحتمال اصطدامه بالأرض معدوم عام 2028...
إليك دراسة نازا حوله بنسبة صحة 99 بالمائة :
Summary
On October 26, 2028, the near-Earth asteroid 1997 XF11 will make a close approach to Earth. Although initial reports indicated an extremely close passage, the current analyses predict an approach distance of 0.00636 AU (951,000 km, 591,000 mi) or about 2.5 times farther than the moon. The probability that the asteroid will impact the Earth is effectively zero. (See JPL's press release.)
1997 XF11, an Apollo type asteroid, was discovered by Jim Scotti of the Spacewatch group at the University of Arizona's Lunar and Planetary Laboratory. The asteroid's orbit was derived from about 100 observations taken since that time as well as 4 pre-discovery observations taken in 1990 by Eleanor Helin, Ken Lawrence, and Brian Roman as a part of the Palomar Planet Crossing Asteroid Survey.
Key points:
probability of Earth impact is zero with and without the 1990 pre-discovery observations
effect of the 1990 pre-discovery observations moved the 2028 close-approach distance farther away and reduced the approach distance uncertainties
the same uncertainty analysis used here for 1997 XF11 was used for the Galileo spacecraft flybys of asteroids 951 Gaspra and 243 Ida --- at encounter, both asteroids were found to lie well within their error ellipsoids.
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* Orbit Plot
The orbit of 1997 XF11 and the inner planets is shown below (all bodies are orbiting counter-clockwise in this ecliptic projection). >From the time of the plot (March 12, 1998), the Earth and 1997 XF11 will orbit the sun approximately 31 and 18 times, respectively, prior to their close-approach on October 26, 2028.
The line of nodes is the intersection of 1997 XF11's orbit plane with the orbit plane of the Earth. Notice that the asteroid passes across the line of nodes (descending through the Earth's orbital plane) at a point very near the Earth's orbit track.
Figure 0. This plot shows orbits of 1997 XF11, Mars, Earth, Venus, and Mercury projected on the ecliptic plane on March 12, 1998. The original full-size plot (created by Paul Chodas, 1998-May-20) is also available as a PostScript file.
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* Earth Target-Plane Position Plots
This section illustrates the uncertainties in the close approach predictions and how they are affected by the inclusion of the pre-discovery observations. These uncertainties are depicted in the "Earth target-plane" which is the plane perpendicular to the geocentric velocity vector of the asteroid at the time of closest approach on October 26, 2028. The error ellipse (show on the following plots) encloses all the points though which the asteroid is likely (i.e. with 99% probability) to pass. The view in these plots is from the approaching asteroid and about 5 degrees below Earth's equatorial plane with North up. The asteroid passes at right angles through these plots. Note that the error ellipses (shown in red) are so narrow that they appear as lines.
It is important to understand that the position uncertainties associated with any of the orbit solutions used in this analysis constrain the asteroid to pass within the position error ellipses shown below (i.e. 99% probability of being within the error ellipse). In other words, even though we can not say exactly where 1997 XF11 will be on 2028-Oct-26, we can say that it will be somewhere within the position error ellipse. This is what allows us to say that the
probability of Earth impact is zero.
وهذه هي الوصلة :
http://neo.jpl.nasa.gov/news/1997xf11.html
حيث بإمكانك رؤية المسار...
على كل حال : الله يستر من هذه الواحد بالمائة التي تشوب صحة مسار الجرم.... :D
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