How Does Earth Protect Itself from Space Radiation?

We are constantly surrounded by many different types of radiation that are emitted by numerous sources. Some people link the word “radiation” with the word “risk”; believing that all types of radiation pose a risk to humans, animals, plants, and other living things. On the other hand, some people claim that radiation is not as harmful to life as many assume. In reading this article, you will discover answers to the following questions:

What is radiation?

What is space radiation?

Are all types of radiation harmful?

How are we protected from harmful radiation here on Earth?

What is the risk of radiation exposure for astronauts?

What is radiation?

Radiation is the emission or transmission of energy in the form of waves or particles through space. Among the several types of radiation, there are two types of radiation that are emitted by the Sun: 1) Electromagnetic radiation, which consists of visible light, infrared, ultraviolet (UV), gamma (γ) radiation, radio waves, and microwaves; and particle radiation, which consists of alpha radiation (α), beta radiation (β), and neutron radiation.

What is space radiation?

Space radiation is made up of atoms in which electrons have been detached (ionizing radiation). The loss of these electrons is a result of the atom having accelerated in interstellar space to speeds nearly equivalent to that of the speed of light. The atoms which comprise space radiation only possess nuclei. [1]

Difference between ionizing and non-ionizing radiation

a. Ionizing radiation

Ionizing radiation is radiation that has sufficient energy to remove electrons from the orbits of nuclei, thus creating more positively charged atoms or “ionizing” them.

Examples: Alpha particles (α), beta particles (β), gamma rays (γ), and galactic cosmic radiation (GCR), which is radiated from space. 

Risk: Exposure to certain levels of ionizing radiation is very harmful and damaging.

b. Non-ionizing radiation

Non-ionizing radiation is radiation which does not have sufficient energy to detach electrons from their orbits.

Examples: Visible light, ultraviolet (UV) light, infrared light, microwaves, and radio frequencies.

Risk: Non-ionizing can be harmful and have damaging effects, but much less so than ionizing radiation



Ionizing radiation has sufficient energy to alter an atom by removing electrons from the atom, while non-ionizing radiation, which has a lower energy level, is not capable of “ionizing” or detaching electrons from atoms. As a result, ionizing radiation is more dangerous than non-ionizing radiation.

Sources of Space Radiations

Even though non-ionizing radiation has the potential to precipitate damage, it can be obstructed. Earth’s ozone layer, for instance, prevents UV radiation from reaching Earth’s surface, protecting it from possible harm. In contrast to non-ionizing radiation, ionizing radiation is much more difficult to avoid and/or block. As discussed previously, ionizing radiation has enough energy to move through atoms and change them by detaching their electrons. 

The effect of ionizing radiation is cumulative: When ionizing radiation reaches a substance, it ionizes its atoms by detaching their electrons, leaving a substance that is vulnerable to further, progressive damage.

Ionizing radiation in space is categorized into three main groups relating to its source: Galactic cosmic rayssolar flare particles, and radiation belt particles (Van Allen Belts), which are trapped in space around Earth. [1]

a. Cosmic Radiation

Cosmic radiation is a form of high-energy ionizing radiation that primarily originates outside of our solar system, but within the Milky Way galaxy. Cosmic radiation is composed of atoms, which have been detached of their electrons (thus comprised of their remaining nuclei) and are nearly traveling at the speed of light.

The particles of cosmic radiation are heavy, highly energized ions with fully detached electrons. They are capable of ionizing the atoms of objects they pass through, from the skin of animals to metal spacecrafts, and can eventually spawn damage.

b. Solar Flares

Solar flair

A solar flare is a sudden explosion of energy on the Sun’s surface that causes an increase in brightness (this increment of light can be observed on its surface in close proximity to a sunspot). Some solar flares are accompanied by coronal mass ejections (CME), a huge expulsions of plasma and magnetic field from the Sun’s corona, that travel outward from the Sun at speeds 250km/s to 3000km/s. The fastest CMEs (3000 km/s) which travel toward Earth can reach our planet in as little as 15-18 hours, while slower CMEs can take several days to arrive. [2]

b. Van Allen radiation belt

Van Allen radiation belt

The Van Allen radiation belt is a zone of charged particles that are mostly sourced from solar winds. These charged particles have been captured by Earth’s magnetic field, which also effectually retains them in doughnut-shaped zones around Earth. The Van Allen radiation belt is further divided into two radiation belts (the inner radiation belt and the outer radiation belt) in addition to some other radiation belts that exist only temporarily. The inner belt stretches from 644 to 9,656 km (400 to 6,000 miles) above Earth’s surface and the outer belt stretches from 13,518 km to 57,936 km (8,400 to 36,000 miles) above Earth’s surface. [3]

How does Earth protect itself from radiation?

Life on Earth is protected from the various solar and cosmic radiation discussed in this article with the help of its magnetic field, which surrounds the planet, as well as its atmosphere.


In conclusion, space possesses different types of radiation that can be very harmful and have dangerous effects. Ionizing and non-ionizing radiation are two types of radiation that exist in space. Ionizing radiation is more harmful than non-ionizing radiation as it has sufficient energy to detach electrons from atoms, creating more positively charged atoms. Ultimately, Earth does an excellent job of protecting humans, animals, and plants from the harmful radiation that exists in our universe with the help of its magnetic field and atmosphere, which capture radiation to prevent it from reaching the surface of our planet.

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