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

After the Noah's Ark story, God gives a rainbow as the sign of the covenant with Earth.

Genesis 9 presents the rainbow as a reminder of God's promise never again to destroy all flesh with a flood. The covenant is made with Noah, his descendants, and every living creature, not only with one family.

The passage describes the rainbow appearing in the clouds and serving as a visible sign when clouds gather over the earth. In the biblical narrative, it therefore has a theological meaning in addition to its natural appearance.

The rainbow is sometimes described as a promise never to have any flood anywhere. Genesis specifically frames the promise as a prohibition against another worldwide destruction of all life by flood. The distinction helps separate the text's covenant language from later symbolic uses of the rainbow.