H083
If the Sun were a basketball, how far away would the nearest star be?
Pictures of the solar system put the planets side by side like beads on a string, with the stars as a nearby backdrop. The real distances don't fit on any page.
The solar system at basketball scale
Sun shrunk to 9.4 inches across; every distance shrunk by the same amount
Space is almost entirely empty, and the gaps between stars dwarf the gaps between planets. Shrink the Sun to a basketball and Earth becomes a grain of sand about 84 feet away, and the Moon sits less than three inches from it. Neptune, the farthest planet, is about half a mile from the basketball. The nearest other star, Proxima Centauri, would be about 4,300 miles away: one basketball in New York and the next one near Rome, with almost nothing in between.
Diagrams squeeze sizes and distances onto one page, and our sense of scale follows the diagram. When a picture shows things close together, ask whether it is drawn to scale.
Try it somewhere else
A textbook drawing shows an atom as a nucleus with electrons circling close around it.
If the nucleus were a marble, how far away do you think the electrons would be?
Checking the math
The Sun is about 864,000 miles across; a men's basketball is about 9.4 inches across. Every distance is divided by the same factor, about 5.8 billion. Earth's 93 million miles becomes about 84 feet. Neptune's 2.8 billion miles becomes about 2,500 feet. Proxima Centauri, 4.24 light-years or about 25 trillion miles away, becomes about 4,300 miles. (For the atom question: with a marble nucleus, the electrons would be roughly a quarter mile to a mile away.)
Related exhibits
Sources: Sun diameter and planet distances: NASA Solar System Exploration. Proxima Centauri distance (4.24 light-years): NASA. Scale calculations by Hanten.