A new YouTube video about the sun has gone viral. In it, people are shown what their skin looks like to the sun by displaying their skin under ultraviolet light. These individuals saw freckles, age spots, and other discolorations that were not visible to the naked eye. They found that their skin was not as youthful as they thought and these spots would soon be visible to everyone.

The video then shows how sunscreen changes what the sun sees. In the video, sunscreen essentially turns the skin black to the sun. It is a protective shield against the ultraviolet light, covering the vulnerabilities that are otherwise seen and exploited by the sun. People are very quick to agree to put on sunscreen, now that they have seen the difference.

Time explains that the video shows how damage from ultraviolet rays can exist outside the visual spectrum. However, this damage has very real health consequences, with the risk of wrinkles, liver spots, and even skin cancer. Thomas Leveritt, the videographer who filmed this piece, has asked if people are willing to “put on some damn sunscreen already.”

According to the Skin Cancer Foundation, sunscreens help prevent ultraviolet rays from reaching the skin. There are two types of ultraviolet rays: UVA and UVB. Different sunscreens protect against these types in different ways. Broad-spectrum sunscreens are able to protect against both. The U.S. Food and Drug Administration (FDA) recommends using a broad spectrum sunscreen with an SPF value of 15 or higher, reapplying every two hours, and limiting sun exposure time, especially during the middle of the day when rays are most intense.