Sometimes all it takes is a bit of sunshine to make you feel better. This is especially true for Superman.

If you caught the five-minute Superman preview that played before A Minecraft Movie, then you would’ve seen David Corenswet’s Man of Steel dragged to the Fortress of Solitude by Krypto, where his trusty robots healed his injuries by exposing him to concentrated sunlight.

Sunshine always makes me feel better, but it doesn’t heal my fractured bones or damaged internal organs. So, why did that work for Superman? For starters, Superman is a Kryptonian and (as far as I know) I’m not.

Superman’s unique biology gives him enhanced strength, durability, flight and other special abilities when he’s near a yellow sun. This is also the case for other Kryptonians like Supergirl and General Zod, and Kryptonian-human hybrids like Superman’s son Jon Kent.

According to Superman Unchained #2, Superman absorbs roughly 140 gigawatts of solar energy at any given moment, and his body stores that energy and uses it to fuel his powers. That’s why Superman’s powers still work at night, or when he’s indoors and out of the sun. There is one catch, however. It has to be a yellow sun.

Superman’s homeworld of Krypton was located in a solar system with a red sun. Under a red sun, Kryptonians have no powers and their bodies are more or less like ordinary humans. This isn’t just an inconvenience—it’s a weakness that can be exploited. In the past, captors have used red sunlight to subdue and imprison Kryptonians.

Has this always been the case with Superman? Well, believe it or not, this particular piece of lore was created to resolve a plot hole.  The original version of Superman’s origin, as described in 1938’s Action Comics #1, stated that Superman’s then unnamed race had their special abilities due to millions of years of evolution. At the time, Superman’s powers were limited to super-strength and the ability to leap across large distances. Flight and his other signature powers would come later.

However, the important thing to note is that Krypton (unnamed until the 1939 Superman newspaper strip) was meant to be a race of supermen. As Superman’s powers grew and new abilities were added, this raised some questions about Krypton. If the race was powerful enough to fly and withstand explosions, wouldn’t they have been able to survive and escape Krypton’s destruction?

1944’s More Fun Comics #101 (reprinted in Superboy: A Celebration of 75 Years) resolved the discrepancies by explaining that Kryptonians were powerless on their planet, and it was Earth’s unique gravity that gave Superman his powers. This explanation worked until the arrival of Supergirl in 1959’s Action Comics #252.

Kara grew up on Argo City, a Kryptonian city that was surrounded by a dome. When Krypton exploded, the dome protected the people of Argo City, sending their home flying into space. When Kryptonite radiation began to infect the city, Kara Zor-El was sent to Earth, where she became Supergirl.

This raised some questions. If the citizens of Argo City were launched into space, and they escaped Krypton’s gravity field, why didn’t they get superpowers?  The answer came when Supergirl’s origin was retold in Action Comics #262.

“But why weren’t my people also super-strong when free of Krypton’s heavy gravity?” Kara asks in a flashback.

“Because our super-powers come partly from less gravity, plus ultra solar rays that penetrate Earth day and night!” Superman explains. “These rays only affect people who were born in other solar systems than Earth’s. And only yellow stars like Earth’s sun emit those super-energy rays! On planets of non-yellow suns, we would not be super-powered, even under low gravity.”

“I see!” Kara replies. “Krypton had a red sun, so the people on the chunk I lived on didn’t become super.”

And thus, an important piece of Superman lore was born. If Supergirl hadn’t been introduced, then it’s possible the yellow sun would have never become the source of Superman’s powers.

Over time, the initial gravity explanation was dropped entirely, with the yellow sun being the primary source of Superman’s power. Creatively, it seems to have been the right choice, as it’s inspired some interesting stories. In 1963’s Superman #164 (reprinted in Lex Luthor: A Celebration of 75 Years), Luthor and Superman travel to a planet orbiting a red sun so they can have a fair fight without any powers. The Superman: The Animated Series episode “Solar Power” features the villain Luminus turning Earth’s sun red, forcing Superman to rescue his friends without his powers.

Probably most significantly, an alien entity called the Sun-Eater began draining Earth’s sun during the 1996 crossover miniseries The Final Night. The sun’s depleted energy caused Superman to slowly lose his powers. Although the sun was restored by the end of the storyline, Superman’s powers didn’t fully return until the 1998 one-shot Superman Forever.

So, if you ever find an injured Superman, don’t be afraid to leave him out in the sun (as long as it’s yellow). A healthy dose of sunshine is all you need to get the Man of Steel to continue his never-ending battle for truth, justice and a better tomorrow.

See Superman take flight (thanks to the power of Earth’s yellow sun) in movie theaters the world over on July 11^th!

Joshua Lapin-Bertone writes about TV, movies and comics for DC.com, is a regular contributor to the Couch Club and writes our monthly Batman column, "Gotham Gazette." Follow him on Bluesky at @joshualapinbertone and on X at @TBUJosh.