There is a hypothesis that fragments of a body from outer space fell to Earth as a result of the Tunguska event. During decades of investigations at the site of the disaster, stone or iron pieces from a cosmic body we...There is a hypothesis that fragments of a body from outer space fell to Earth as a result of the Tunguska event. During decades of investigations at the site of the disaster, stone or iron pieces from a cosmic body were not found. In spite of this, the number of adherents of this hypothesis is growing. For one thing, it was determined that the formation of swamp craters at the epicentre of the disaster is contempory with the Tunguska event. Secondly, it was proven that the swamp craters are the result of thermokarst processes: their formation is connected with heat exchange in a permafrost zone. Now we can affirm that fragments of the Tunguska cosmic body (as a comet) with a mass of 10-3 ≤ M ≤ 10 kg reached the Earth’s surface, but they did not form craters. This conclusion was made from the isotopes and composition of element in peat deposits as determined by Kolesnikov’s group and L’vov.展开更多
Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20<sup>th</sup> century. These reliefs consist of several tens (up to hundreds) of stripes that have ...Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20<sup>th</sup> century. These reliefs consist of several tens (up to hundreds) of stripes that have arisen as a result of the destruction of vegetation and the surface layer of the ground. Structures of stripes are extended, ranging in size from 6 km to ≥20 km, with a width of several kilometers. Every strip (scratch on the ground) is roughly estimated to be up to 50 m wide and ≥500 m long. The stripes start from one edge of the relief and stretch at inter-vals to the other, slightly diverging symmetrically from the central axis. It was determined that these reliefs are not associated with the movement of soil (avalanches, mudflows) or with the impact of air currents (hurricanes, storm, tornado). Geographically, these struc-tures of stripes are located within a circle with a radius of 770 km, described around the epicenter of the Tunguska catastrophe.展开更多
A space object exploded near the city of Chelyabinsk on February 15, 2013. Meteorite fragments reached the Earth’s surface, and accordingly we may consider this space object to have been a meteorite. However, this ev...A space object exploded near the city of Chelyabinsk on February 15, 2013. Meteorite fragments reached the Earth’s surface, and accordingly we may consider this space object to have been a meteorite. However, this event showed a number of features not corresponding to the destruction of a meteorite. The space object began to disintegrate at an altitude of 70 km when pressure (dynamical loads) on its front surface was ~6.7 × 103 N·m-2. The substance from the object’s surface was not blown off by drops, as at ablation, but was dumped by jets over a distance up to 1 km. The trail of this space object visually reminded us of a jet aircraft’s contrail, made up of water. But there is no enough water at altitudes of 30 - 70 km. It may be assumed that the object itself delivered water to these altitudes. The calculation of gas rise over the trail showed that the temperature in some parts of this trail was about 900 K. Heating of large masses of gas can be explained not only by the release of kinetic energy of the space object, but also by combustion processes of its substance. Thus, it was concluded that the meteorite could have been delivered by a comet.展开更多
文摘There is a hypothesis that fragments of a body from outer space fell to Earth as a result of the Tunguska event. During decades of investigations at the site of the disaster, stone or iron pieces from a cosmic body were not found. In spite of this, the number of adherents of this hypothesis is growing. For one thing, it was determined that the formation of swamp craters at the epicentre of the disaster is contempory with the Tunguska event. Secondly, it was proven that the swamp craters are the result of thermokarst processes: their formation is connected with heat exchange in a permafrost zone. Now we can affirm that fragments of the Tunguska cosmic body (as a comet) with a mass of 10-3 ≤ M ≤ 10 kg reached the Earth’s surface, but they did not form craters. This conclusion was made from the isotopes and composition of element in peat deposits as determined by Kolesnikov’s group and L’vov.
文摘Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20<sup>th</sup> century. These reliefs consist of several tens (up to hundreds) of stripes that have arisen as a result of the destruction of vegetation and the surface layer of the ground. Structures of stripes are extended, ranging in size from 6 km to ≥20 km, with a width of several kilometers. Every strip (scratch on the ground) is roughly estimated to be up to 50 m wide and ≥500 m long. The stripes start from one edge of the relief and stretch at inter-vals to the other, slightly diverging symmetrically from the central axis. It was determined that these reliefs are not associated with the movement of soil (avalanches, mudflows) or with the impact of air currents (hurricanes, storm, tornado). Geographically, these struc-tures of stripes are located within a circle with a radius of 770 km, described around the epicenter of the Tunguska catastrophe.
文摘A space object exploded near the city of Chelyabinsk on February 15, 2013. Meteorite fragments reached the Earth’s surface, and accordingly we may consider this space object to have been a meteorite. However, this event showed a number of features not corresponding to the destruction of a meteorite. The space object began to disintegrate at an altitude of 70 km when pressure (dynamical loads) on its front surface was ~6.7 × 103 N·m-2. The substance from the object’s surface was not blown off by drops, as at ablation, but was dumped by jets over a distance up to 1 km. The trail of this space object visually reminded us of a jet aircraft’s contrail, made up of water. But there is no enough water at altitudes of 30 - 70 km. It may be assumed that the object itself delivered water to these altitudes. The calculation of gas rise over the trail showed that the temperature in some parts of this trail was about 900 K. Heating of large masses of gas can be explained not only by the release of kinetic energy of the space object, but also by combustion processes of its substance. Thus, it was concluded that the meteorite could have been delivered by a comet.
