Comments on: Tadpole on Mars

By: Robert Zimmerman

Robert Zimmerman — Sat, 18 Jan 2020 15:32:17 +0000

In reply to Jeff. Jeff: This is intriguing, but not surprising. This illusion happens to everyone. Sometimes you simply have to turn the picture upside-down to get the shadows right. Sometimes you just have to train your mind to recognize where the sunlight is coming from.

By: Andi

Andi — Sat, 18 Jan 2020 14:54:09 +0000

It’s a common optical illusion. If you look at the picture long enough, you can interpret it both ways

By: Jeff

Jeff — Sat, 18 Jan 2020 11:52:25 +0000

I agree with Carl. The cropped image does indeed look like a raised dome with a raised twisting appendage. As soon as I look at the full image though, the true relief unfolds.

By: Robert Zimmerman

Robert Zimmerman — Sat, 18 Jan 2020 06:02:40 +0000

In reply to Carl. Carl: The sun in the case of the main image is coming from the west and is about 51 degrees above the horizon when the picture was taken (info from the link). Thus shadows are cast on the western walls of the canyon. The shadows you see on the floor of the crater appear to be caused by a central ridgeline extending out into the canyon floor aligned with the canyon itself. I imagine that this is material that has, over time, flowed into the crater from out of the canyon, pushed by wind and avalanches. I hope that answers your question.

By: Carl

Carl — Sat, 18 Jan 2020 05:40:46 +0000

Why does the tadpole tail leave a shadow if it’s a canyon ?