SORU: aşağıdaki parçaya göre cevaplayınız
It is stated in the passage that, since Pluto is so far away from Earth, ----.
Pluto, which was until recently regarded as the
outermost and smallest planet in the solar system,
has never been visited by an exploring spacecraft. So
little is known about it that it is difficult to classify. Its
distance from Earth is so great that the Hubble Space
Telescope cannot reveal its surface features.
Appropriately named for the Roman god of the
underworld, it must be frozen, dark, and dead. Its
mean distance from the Sun is 5,900 million
kilometres. In fact, it has the most eccentric orbit in
the solar system, bringing it at times closer to the Sun
than Neptune. Furthermore, there is evidence that
Pluto has an atmosphere, containing methane, and a
polar ice cap that increases and decreases in size
with Pluto's seasons. It is not known to have water.
The Hubble Space Telescope's faint-object camera
revealed light and dark regions on Pluto, indicating
an ice cap at the north pole. It is not known if there is
an ice cap at Pluto's south pole.