If its a total lunar eclipse why does one edge remains brighter than the rest?

I have been googling for an answer for a while and cant find it. Even pictures of previous total lunar eclipses are the same. Is it because that side remain closer to the edge of the umbra? Or is it caused by how light behaves; Or because the surface of the moon is more reflective on that part.

  • Xaphanos@lemmy.world
    6·
    14 hours ago

    Go out on a sunny day. Get in the shadow of a building - near the edge. Notice that you can know when the sun is close to becoming visible by the scattered light. One side is brighter.

    Now imagine being in orbit of earth. Watch the sun set behind it. You see the sky glowing in the direction of the sun. Same as the building. Same as regular sunsets.

    Now go to the moon. Because of the extreme distance, you can see the “sunset” entirely around the globe. That is the red glow. But one side of the moon is closer to the sunset, and (just like the building) that side is brighter.

    Does that help?