Which sub-group of the giant planets includes Uranus and Neptune, distinguished by their specific composition?

In a scale model where the Earth's diameter is reduced to $1\ \text{mm}$, what is the approximate distance between the Earth and the Sun?

True or False: Before modern astronomical observations, the scientific consensus was that the universe was static and that galaxies occupied fixed positions relative to one another.

While gas giants like Jupiter and Saturn are composed primarily of gases, what does the text suggest may be located at their center?

Which statement accurately describes the scale of a galaxy in relation to our solar system?