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The planet Venus has completed a very rare passage across the face
of the sun - an event not witnessed since 1882.
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| Venus
on its transit across the sun |
The
so-called transit of Venus began at about 5:20 am BST with the planet's
tiny black disc edging over the bright limb of our star. The phenomenon
continued for about six hours, ending around 12:24 pm BST.
The
transits have had huge significance in the past, as they were used
by scientists to work out the Sun-Earth distance - and hence to
get a proper scale for the Solar System.
Venus
has been referred to as Earth's hellish counterpart - it's certainly
an extraordinary place.
Its
thick, yellowish clouds contain sulphuric acid. The atmospheric
pressure at the surface is equivalent to that at a depth of 900m
in the Earth's oceans. Venus rotates so slowly on its axis, its
year (225 Earth days) is actually longer than its day.
They
are so rare that it is a very significant event - the next one will
be in 2012, but after that you'll have to wait until 2117.
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