Is there any risk of radiation from the solar eclipse?

The full solar eclipse taking place on Monday, April 8 poses no risk in terms of the radiation reaching earth, although this misconception has been spread on social media. The amount of solar radiation is decreased during an eclipse. That said it is vitally important to wear correct eclipse glasses if you are looking at the sky during the eclipse, because there is still radiation coming to earth around the moon.

During an eclipse the moon comes between the sun and the earth and along a narrow path our satellite blocks the light and radiation from the sun. While the moon is far smaller than the sun (64.3 million moons would fit in the sun) it is much closer and by a quirk of chance they appear to be almost exactly the same size when viewed from earth, meaning the moon can appear to entirely block the sun.

Affect on the atmosphere of the eclipse

When the moon blocks the sun’s rays this reduces the amount of solar radiation reaching our atmosphere during the eclipse. This causes the temperature to drop and decreases the amount ionisation occurring in the upper atmosphere, leading to a drop in the amount of electrons.

This can have an impact on humans, by reducing the capacity of the atmosphere to transmit radio waves. Changes to ionisation can also affect GPS navigation systems.

Generally, the ionosphere goes back to normal once the eclipse ends and the solar radiation goes back to normal.

Extreme precaution while looking at the eclipse

While much of the light and radiation from the sun is blocked by the moon during the eclipse, some, including infrared radiation, is able to come round the moon. This makes it particularly dangerous to look at the eclipse without appropriate eyewear, because the pupil in the eye will dilate, adjusting to the darkness, meaning the retina can be be damaged permanently by the radiation that is reaching the eye.

If you are going to look at the eclipse, you must wear appropriate eyewear.