yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

TIL: Why Mars's Ocean Disappeared | Today I Learned


2m read
·Nov 11, 2024

This is what Mars looks like today, and this is what it may have looked like 3 to 3.5 billion years ago. Notice the difference? Well, the planet was warmer and wetter, and it even had an ocean that covered the entire Northern Hemisphere. So where did that ocean go?

I'm Brendan Mullen, an astrobiologist and emerging explorer with National Geographic, and I'm going to tell you what happened 4 and 1/2 billion years ago when the solar system first formed. Earth and Mars formed from basically the same sort of stuff, like carbon, silicates, oxygen, nitrogen, you know, stuff like that. They're basically the same, except for one key difference: that's size. If we shrunk Earth and Mars down to scale and let's say, let's make Mars the size of a softball, Earth would be the size of a bowling ball. It's a big difference!

And in the universe, size matters. When Earth and Mars and all the other planets first formed, they were very hot, and they've been cooling off since. But the size difference means everything. Earth still has a churning liquid metal core in it, while Mars is essentially frozen solid. Without a turning molten core like on Earth, Mars doesn't have a magnetosphere, a protective magnetic field around the planet. Without the magnetosphere, the solar wind or charged particles from the Sun hit the atmosphere and strip off molecules and atoms over time. So billions of years later, we have far less atmosphere on Mars than we used to.

So what does that have to do with Mars's disappearing ocean? Well, without that pressure of the atmosphere on top of it, that water evaporates out into space or freezes beneath the surface. But we can still see the role that it played in shaping the Martian terrain. Is there a chance we'll find life on the surface of Mars? The answer is actually yes. If we found that life, what I would really be ashamed to say is that we did something bad to it.

More Articles

View All
Little Farms, Big Movement | Branching Out | Part 2
Today my family and I are hitting the road in search of a farm. A vertical farm is a farm, just like it sounds, that is stacked. But since I’m leading this family adventure, it’s not just gonna be your average farm. We are on the hunt to find the next gen…
3 FREE ways to future-proof your skills in the AI age
With the rise of AI, the job market is shifting fast. Here are three things you can practice for free on Khan Academy to future-proof your job skills. Number one is critical thinking. While AI can handle vast amounts of data, in the end, it’s humans who …
Divergence notation
So I’ve said that if you have a vector field, a two-dimensional vector field with component functions P and Q, that the divergence of this guy, the divergence of V, which is a scalar-valued function of X and Y, is by definition the partial derivative of P…
HOW TO BUILD GOOD STUDY HABITS
Hey guys, today’s video is about building good study habits. I think this is a really important topic because lots of smart people do themselves a disservice by not building up good habits. I always hear people say that another person is lucky because the…
The Origins of Disgust
Being impressed by the cognitive abilities of a chimpanzee isn’t just good for them; it is good for us, because it helps us learn about our own evolutionary history. Comparing the psychology of humans to the psychology of other primates is a great way to …
Cao Dai's History in Vietnam | The Story of God
[music playing] MORGAN FREEMAN: The Cao Dai religion, an unusual blend of eastern and western faiths, appears to be flourishing in Vietnam. Across the country, there are almost 400 temples. Followers worship openly. But it wasn’t always that way. I’ve be…