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Dangers from
outer space
The outer space has a large number of
solid objects, of varying sizes, moving
around the sun. When they cross
Earth’s orbit, a collision could occur.
The larger comets, rocky asteroids, and
their fragments can lead to a disaster.
Fortunately, the probability of a big
disaster is very low. However, it is perhaps
the only natural disaster that could lead to
the extinction of mankind.
Tunguska event, Siberia, 1908
On the morning of 30 June, 1908, a huge
explosion occurred near the Tunguska river
in Central Siberia, Russia. A large space rock,
possibly an asteroid, about 36.5 metres in
diameter, entered the atmosphere of Siberia
and then exploded into fragments in midair.
The energy released was equal to fifteen
megatonnes of TNT. (One large hydrogen
bomb makes an explosion as big as one megatonne of TNT!) The seismic vibrations
caused by the impact were recorded as far away as England. If the explosion had occurred
four hours and forty-seven minutes later, the Russian capital of St Petersburg would have
been hit and completely destroyed.
Impact … The Tunguska event caused more damage
than could be caused by the detonation of
In the isolated forest area of Tunguska, hundreds several dynamites.
of reindeer died. A few hunters or trappers were
camping thirty kilometres away. They were
blown into the air and lost consciousness. No
one was reported dead.
For days after the explosion, there was fine dust
in the atmosphere, reflecting so much light from
beyond the horizon that people in Europe could
read newspapers out in the open at night.
TICKER The sixty-five-million-year-old Chicxulub impact crater on the Yucatan peninsula of Mexico is
outer space
The outer space has a large number of
solid objects, of varying sizes, moving
around the sun. When they cross
Earth’s orbit, a collision could occur.
The larger comets, rocky asteroids, and
their fragments can lead to a disaster.
Fortunately, the probability of a big
disaster is very low. However, it is perhaps
the only natural disaster that could lead to
the extinction of mankind.
Tunguska event, Siberia, 1908
On the morning of 30 June, 1908, a huge
explosion occurred near the Tunguska river
in Central Siberia, Russia. A large space rock,
possibly an asteroid, about 36.5 metres in
diameter, entered the atmosphere of Siberia
and then exploded into fragments in midair.
The energy released was equal to fifteen
megatonnes of TNT. (One large hydrogen
bomb makes an explosion as big as one megatonne of TNT!) The seismic vibrations
caused by the impact were recorded as far away as England. If the explosion had occurred
four hours and forty-seven minutes later, the Russian capital of St Petersburg would have
been hit and completely destroyed.
Impact … The Tunguska event caused more damage
than could be caused by the detonation of
In the isolated forest area of Tunguska, hundreds several dynamites.
of reindeer died. A few hunters or trappers were
camping thirty kilometres away. They were
blown into the air and lost consciousness. No
one was reported dead.
For days after the explosion, there was fine dust
in the atmosphere, reflecting so much light from
beyond the horizon that people in Europe could
read newspapers out in the open at night.
TICKER The sixty-five-million-year-old Chicxulub impact crater on the Yucatan peninsula of Mexico is
