ClassX Video Lessons Youtube Channel MinuteEarth UPSIDE-DOWN Rivers On Mars?! (Response to MinutePhysics)
Hey there! Have you ever looked at a picture and found it hard to tell if something is sticking out or sinking in? This happens because of the way light and shadows play tricks on our eyes. Recently, a fascinating photo of Mars sparked a conversation about this at MinuteEarth.
In the photo, there’s a winding pattern that looks like an ancient river channel. This tells us that liquid water once flowed on Mars. But here’s the twist: the shadows in the picture make it look like the river channel is raised above the ground, which is strange because rivers usually carve valleys, not hills.
So, how can a river channel be higher than the land around it? This is due to a process called “inverted relief.” Imagine walking in the snow. When the sun comes out, the snow around your footprints melts, but the compacted snow in your footprints stays, making them look like they’re sticking out.
The same thing can happen with river valleys. In dry places, rivers can dry up, and water from below the ground can rise up. When this water evaporates, it leaves behind minerals that harden the riverbed. Over time, this hardened riverbed becomes tougher than the surrounding land. Wind and other forces erode the softer land, leaving the riverbed raised up like a ridge.
We can’t be sure exactly how the Martian riverbed became inverted without more exploration. However, by studying similar formations on Earth, scientists can make educated guesses. You can even explore these formations using Google Earth, but be careful—it can be tricky to figure out which way is up!
Hi, I’m Ever, and I illustrated the video. Many people ask how I make animations like these. It’s not magic; it’s all about using the right tools and learning from the best. I love taking online classes, and Skillshare is a great place to learn new skills, from video editing to designing T-shirts. They offer thousands of classes, and the first 200 people to click the link in the description can get a 2-month free trial!
Hope you enjoyed learning about upside-down rivers on Mars! Keep exploring and discovering new things!
Use clay or playdough to create a model of an inverted river channel. Shape the riverbed to be higher than the surrounding land. This will help you visualize how inverted relief works. Take a picture of your model and explain the process of inverted relief to your classmates.
Use Google Earth to find examples of inverted river channels on Earth. Look for areas where the riverbeds appear raised. Take screenshots of your findings and present them to the class, explaining how these formations are similar to those on Mars.
Conduct an experiment with a flashlight and various objects to see how shadows can change the perception of depth. Arrange objects to create different shadow effects and observe how they can make surfaces appear raised or sunken. Share your observations with the class.
Research the history of water on Mars and how scientists believe it has shaped the planet’s surface. Create a presentation or poster that explains the evidence of past water flow and how it relates to the concept of inverted river channels.
Try your hand at creating a simple animation that illustrates the concept of inverted relief. Use free online tools or apps to animate the process of a river channel becoming inverted over time. Share your animation with the class and discuss the techniques you used.
Sure! Here’s a sanitized version of the transcript:
—
Hi, this is Emily from MinuteEarth. A little while back, Henry made a great MinutePhysics video about how the symmetry of light and shadows on a landscape can make it difficult for our brains to determine which features are raised and which are recessed, especially when the light source is unclear. This sparked a discussion at MinuteEarth about a specific photo of the surface of Mars.
The sinuous pattern in the landscape is an ancient stream channel, indicating that liquid water once flowed on Mars. However, the crater above it casts a shadow in the top left, suggesting that the light in the image comes from that direction, which implies that the stream channel is elevated above the surrounding landscape. But that seems counterintuitive, as river channels are typically valleys formed by erosion.
Despite my initial belief that it was a valley, it turns out that this stream channel is an example of a geological process that creates inverted relief. If you live in a cold climate, you might have seen something similar with compacted footprints in the snow—when the sun melts the surrounding snow, the footprints can appear to stick out.
The same process can occur with a river valley. For example, in a desert, a stream may dry up due to lack of rain. As it does, groundwater can be drawn upward by capillary action. When this water evaporates, it leaves behind dissolved minerals that coat and cement the sediments in the riverbed. Over time, as the stream flows and dries repeatedly, more cement accumulates, making the riverbed more resistant to erosion than the surrounding rock. Eventually, wind erodes the softer rock, resulting in an inverted version of the original channel.
While we can’t determine exactly how this Martian riverbed became inverted without further exploration, we can make educated guesses by studying similar formations on Earth. You can even find examples using Google Earth, but be cautious—figuring out which way is up can be quite confusing!
Hi, this is Ever, and I illustrated this video. Many of you have asked how I create animated effects like this one. It’s not magic; it’s quite simple with the right tools and guidance. I prefer online classes, and Skillshare offers a fantastic library of over 17,000 how-to classes on various topics, from video editing to T-shirt design. The first 200 people to click the link in the description will receive a 2-month free trial.
—
Let me know if you need any further modifications!
Mars – The fourth planet from the Sun in our solar system, known for its reddish appearance due to iron oxide on its surface. – Scientists are studying Mars to understand if it ever had conditions suitable for life.
River – A large, flowing body of water that usually empties into a sea or ocean. – The Amazon River is one of the longest rivers in the world and flows through several countries in South America.
Channels – Narrow bodies of water that connect two larger bodies of water or pathways through which water flows. – The channels on Mars suggest that liquid water might have once flowed on its surface.
Water – A transparent, tasteless, odorless, and nearly colorless chemical substance, essential for all known forms of life. – Water covers about 71% of the Earth’s surface, mostly in seas and oceans.
Shadows – Dark areas or shapes produced by a body coming between rays of light and a surface. – The shadows of the mountains on the Moon help scientists understand its surface features.
Relief – The variation in elevation and slope of the land surface in a particular area. – Topographic maps show the relief of the land, helping geographers understand the terrain.
Erosion – The process by which natural forces like water, wind, or ice wear away rocks and soil. – Erosion can change the landscape dramatically, forming valleys and canyons over time.
Minerals – Natural, inorganic substances with a definite chemical composition and crystalline structure. – Geologists study minerals to learn about the Earth’s history and the processes that formed it.
Earth – The third planet from the Sun, home to millions of species, including humans, and the only known planet to support life. – The Earth’s atmosphere is crucial for sustaining life by providing oxygen and protecting us from harmful solar radiation.
Exploration – The act of traveling through an unfamiliar area in order to learn about it, often used in the context of space or scientific discovery. – Space exploration has led to many technological advancements and a better understanding of our universe.
