* The planets are constantly moving. Their distances from each other are constantly changing as they orbit the Sun.
* "Across" can be interpreted in different ways. Do you mean the distance between the Sun and Neptune, or the distance between Earth and Neptune?
Here's a breakdown:
* Sun to Neptune: The average distance between the Sun and Neptune is about 2.8 billion miles (4.5 billion kilometers). This is also known as Neptune's semi-major axis.
* Earth to Neptune: The distance between Earth and Neptune varies significantly depending on their positions in their orbits. At their closest, they can be about 2.7 billion miles (4.3 billion kilometers) apart. At their farthest, they can be over 3 billion miles (4.8 billion kilometers) apart.
So, the answer to your question depends on what you mean by "across" and when you're measuring the distance.
