Can You Fit All the Planets Between the Earth and Moon?

The Moon seems pretty far away, but is it distant enough that you can fit all the planets between the Earth and the Moon? The answer is yes, but only sometimes! The Moon’s orbit around the Earth is elliptical (not a perfect circle). When the Moon is at its closest approach (perigee), the planets don’t fit inside the orbit. However, when the Moon is at is furthest distance (apogee), all the planets (plus the dwarf planets Pluto and Eris) fit nicely.

Can You Fit All the Planets? Let’s Do the Math

How do you figure out whether the planets fit between the Earth and the Moon? First, you need the diameters of all of the planets. Next, you add them up. Finally, you compare this value with the distance between the Earth and Moon.

Adding Up the Size of the Planets

Here are the sizes of the planets from NASA’s Jet Propulsion Lab:

Adding up the diameter values, you get a variety of numbers, depending on whether or not you include the major dwarf planets in the mix:

• 387942 km (no Pluto or Eris)
• 390318 km (with Pluto)
• 392718 km (with Pluto and Eris)

The planets of the solar system aren’t perfectly round. The gas giants (Jupiter, Saturn, Uranus, and Neptune) are distinctly flattened. They are wider across their equators and narrower pole-to-pole. While JPL does not give the polar diameters, the mean radius factor this in. Using the mean radius of each planet and cramming them together at their thinnest points, you get roughly 380012 km (without Pluto or Eris).

The Distance Between the Earth and the Moon

The distance between the Earth and Moon is not a constant. The Moons orbit is elliptical, plus it has some wobble to it (perturbations) from gravitation effects of other planets in the solar system. The Moon is closest to the Earth at perigee and furthest away at apogee. Even these distances vary from one year to the next.

• Perigee 362600 km (356400-370400 km)
• Apogee 405400 km (404000-406700 km)

Perigee and apogee are distances between the gravitational centers of the Earth and Moon. So, the distance between the surface of the Earth and Moon is slightly lower.

• Mean radius of the Earth 6371.0 km
• Mean radius of the Moon 1737.4 km

Adding these two values, you get 8108.4 km of Earth and Moon that you need to subtract from perigee and apogee:

• Distance between the surfaces of the Earth and Moon at perigee = 362600 – 8108.4 = 354491.6 km
• Distance between the surfaces of the Earth and Moon at apogee = 405400 – 8108.4 = 397291.6 km

As you can see, the distance between the Earth and Moon varies quite a lot.

Putting It All Together

Finally, we have the length of all the planets added up and the distance between the Earth and Moon.

• The planets of the solar system fit between the Earth and Moon at apogee, even if you include Pluto and Eris.
• The planets of the solar system do not fit between the Earth and the Moon at perigee, even if you smush them up as tightly as possibly and leave out Pluto and Eris.

You might put the terrestrial planets within the atmospheres of the gas giants and even have those atmospheres overlap in order to get the planets to fit at perigee. But, that’s a stretch. They still might not fit.

Can the Solar System Fit Between the Earth and Moon?

While the planets sometimes fit between the Earth and Moon, the entire solar system does not. This is because the Sun does not fit between the Earth and Moon. The diameter of the Sun is 1,392,000 km, which is roughly 3.6 times the distance between the Earth and Moon.

Can the Sun Fit Between the Earth and Moon?

All the planets might fit between the Earth and Moon, but the Sun is a different matter entirely.

References

• Archinal, B.A.; et al. (2018). “Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2015.” Celestial Mech. Dyn. Astr. 130:22.
• Battat, J. B. R.; Murphy, T. W.; Adelberger, E. G. (2009). “The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO): Two Years of Millimeter-Precision Measurements of the Earth-Moon Range”. Astronomical Society of the Pacific. 121 (875): 29–40. doi:10.1086/596748
• Brown, Michael E.; Schaller, Emily L. (2007). “The Mass of Dwarf Planet Eris.” Science. 316:1585. doi:10.1126/science.1139415
• Jet Propulsion Laboratory. “Planetary Physical Parameters.”