Video Transcript
Which planet in the solar system is
closest to the Sun? (A) Venus, (B) Uranus, (C) Earth,
(D) Neptune, or (E) Mercury.
To understand this question, we
first need to understand what is meant by the term “solar system.” In the solar system is a massive
sphere of hot gas. This is the Sun. There are objects that orbit, or
move around, the Sun in roughly circular paths. There are eight planets that orbit
the Sun. These are not drawn to scale as
they are not at the correct distances and are not the correct sizes. We have only drawn them close
together in a neat line to make it easier to label and identify them.
This is the solar system. This refers to the Sun and
everything that orbits around it, including the eight planets. So, the planet in the solar system
closest to the Sun is this planet here. Two of the options are outer
planets: Uranus and Neptune. These outer planets are also
referred to as gas giants.
Gas giants are planets that don’t
have a surface. They are not solid and instead are
made of different gases. There are four gas giants in total,
including Saturn and Jupiter. These four constitute the outer
planets of the solar system. The keyword here is “outer.” These are the four planets far away
from the Sun. The planet furthest from the Sun is
Neptune. So, option (D) is not the correct
answer.
Next is Uranus. So, option (B) is also not the
correct answer. Getting closer to the Sun, we have
Saturn and Jupiter. This completes the outer
planets. The planets that are closer to the
Sun are referred to as the inner planets. There are four of them. The inner planet furthest from the
Sun is Mars. Mars is a reddish planet with a
thin atmosphere. Earth, the next planet, is our
home. So, option (C), Earth, is not the
correct answer.
We have established that there are
eight planets in the solar system. So, we know that there are just two
planets left to identify, giving us our four inner planets, which, along with the
four outer planets, gives us a total of eight planets in the solar system. The two planets we have left are
(A) Venus and (E) Mercury. The next planet is Venus. Hence, option (A) is not the
correct answer. While Venus is not the closest
planet to the Sun, it is the hottest. This is because it has a thick
atmosphere that traps in the heat coming from the Sun.
The planet closest to the Sun is
therefore Mercury. Mercury has no atmosphere, which is
why while it is the closest planet to the Sun, it is not the hottest planet in the
solar system, as there is no atmosphere to trap the heat coming from the Sun that
there is on Venus. So, the correct answer is option
(E), Mercury.
