What sign did God place in the sky after the Noah's Ark flood?

After the Noah’s Ark flood, Genesis identifies a rainbow as the sign of God’s covenant with Earth.

In Genesis 9, God establishes a covenant with Noah, his descendants, and every living creature. The rainbow is placed in the clouds as a reminder of the promise that a flood would not again destroy all life on Earth. The passage presents the sign as something visible in the sky and links it directly to the covenant.

The biblical account therefore gives the rainbow religious and symbolic meaning within the story. It does not describe the physical optics that modern science uses to explain rainbows, such as the refraction and internal reflection of sunlight in water droplets.

A frequent mix-up is calling the sign a “rainbow covenant.” The covenant is the promise; the rainbow is the sign associated with it. In Genesis, the sign follows the flood and extends beyond Noah to the whole living world.