The doughnut-shaped radiation barriers surrounding our planet

Space · Published 23 October 2026 Swipe more like this →

In short: Often cited by conspiracy theorists as an impassable barrier to the Moon, the Van Allen belts are actually navigable. These massive, doughnut-shaped zones of trapped, high-energy particles pose a significant challenge for deep-space travel, yet they also serve as a vital shield for life on Earth.

Discovered in 1958 by physicist James Van Allen using data from the U. relatively early U.S. Explorer satellite, these belts consist of energetic charged particles trapped by Earth's magnetosphere. The belts are not a single wall but two distinct regions that merge gradually. The inner belt, centered roughly 3,000 km above the surface, is composed largely of high-energy protons. These protons are thought to result from cosmic rays colliding with Earth's atmosphere, producing neutrons that later decay into protons and electrons.

The outer belt is more complex, containing particles from both the atmosphere and the solar wind, such as helium ions. While the inner belt's protons can exceed 30,000,000 electron volts, the outer belt's most energetic particles are electrons, reaching several hundred million electron volts. This region is centered at an altitude between 15,000 and 20,000 km, though some estimates suggest it may extend as far as 38,000 km from the surface.

Navigating these zones is a matter of precision and speed. Although certain people argue the belts prevent lunar travel, James Van Allen determined that vessels might traverse less intense radiation zones to access deep space. This was proven in 1968 by NASA's Apollo 8, the first crewed mission to fly beyond the belts. However, for future missions to Mars, the radiation from solar storms and cosmic rays remains a primary hazard, necessitating advanced shielding for both humans and sensitive satellite electronics.

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