Mars Has Secrets NASA Still Can’t Explain — Here’s What We Know

Mars looks simple from far away: red ball, thin air, dead desert. Up close, it behaves like that friend who definitely isn’t telling you everything.

NASA has thrown orbiters, landers, and rovers at this planet for decades. We’ve mapped the surface, listened to marsquakes, sniffed the air… and Mars keeps dropping new mysteries on the table.

Let’s walk through some of the strangest things we’ve found so far—and why scientists are still scratching their heads.

Mars Has a Methane Problem (and It’s Weird)

On Earth, methane usually screams “life” or at least “geology doing something dramatic.” On Mars, it mostly screams “???”

NASA’s Curiosity rover has detected tiny puffs of methane in Gale Crater. They rise and fall with the seasons—about 60% higher in Martian summer—then drop back down, like the planet is quietly breathing. Nobody knows why.

Possible explanations:

• Microbes underground, slowly burping gas

• Water–rock reactions deep below the surface

• Ancient trapped methane leaking out through cracks

The problem? The amounts Curiosity sees at ground level don’t match what orbiters see from above. The numbers don’t line up, the timing doesn’t line up, and the models hate it. Scientists have called it a “mystery” for years—and that’s still the official status.

If Mars is leaking methane from life, it’s subtle. If it isn’t, the planet has invented a new way to confuse everyone.

The Dark Streaks That Look Wet… but Probably Aren’t

For a long time, one of the big hopes for present-day liquid water on Mars came from dark lines that appear and fade on steep slopes—like someone poured something down the hillside.

These are called slope streaks and recurring slope lineae (RSL). They grow, branch around rocks, then slowly fade over years. For decades, many scientists suspected salty liquid water trickling through dusty slopes.

Recently, that story flipped.

A huge study looked at around 2 million of these dark streaks. The new conclusion: most of them are probably dry dust avalanches, triggered by wind and other surface processes, not flowing water.

So:

• They look like wet flows.

• They act like something flowing.

• But the best current evidence says they’re ultra-fine dust moving like a liquid in low gravity.

Does that kill the dream of liquid water on modern Mars? Not completely—briny pockets could still exist in special spots—but it does shove most of the “running water today” ideas into the “probably not” box.

For a good technical overview of Mars’ changing surface features and dust activity, NASA’s Mars Exploration Program has a solid breakdown.

Marsquakes Revealed a Messy Interior

Then there’s what’s happening inside the planet.

NASA’s InSight lander spent years listening to marsquakes. From those tiny shakes, scientists reconstructed the interior: crust, mantle, core. And Mars did not come out simple.

Some key surprises:

• Mars has a solid inner core plus a liquid outer core, more Earth-like than expected. 

• Seismic data suggests dense “blobs” buried in the mantle, likely leftovers from early violent impacts—basically the fossil pieces of failed baby planets that slammed into Mars and never fully mixed in.

Those blobs can be up to a few kilometers across and have been sitting there for billions of years. Earth’s plate tectonics would’ve chewed and recycled that kind of structure long ago. Mars just… kept them.

So the interior of Mars isn’t a neat layer cake. It’s more like someone baked a cake, hurled a few other cakes at it at high speed, then never cleaned up the mess.

For a deeper dive into InSight’s results and what they tell us about planetary formation, you can check the mission education resources from NASA’s Jet Propulsion Laboratory.

Strange Surface History Written in Stone

Rovers like Curiosity and Perseverance keep finding rocks that say, “Mars used to be very different.”

A few examples:

• Ancient lake ripples: Curiosity photographed rocks that still hold tiny wave patterns from a long-gone shallow lake. The area was supposed to be mostly dry in that stage of Mars’ history, so those ripples blew up the nice, simple “wet-then-dry” storyline.

• Layered cliffs and canyon walls: Orbital images show kilometer-deep stacks of sediments, lava flows, and dust layers—each one a climate chapter we don’t fully understand.

Put those together and Mars starts to look like a planet that couldn’t make up its mind:

• Water, then ice, then dust.

• Lakes, then deserts, then maybe short wet episodes again.

ESA’s high-resolution Mars imagery also shows just how complex the landscape is—dust dunes, craters, and rover tracks cutting through terrain shaped by both wind and ancient water.

We know there were long-lasting lakes and rivers billions of years ago. We still don’t know exactly how long they lasted, how stable the climate was, or how many times Mars switched between “almost Earth-like” and “frozen desert.”

So… Is There or Was There Life?

Short answer: we still don’t know. And anyone who says otherwise is selling something.

Here’s what we do have:

• Tough organic molecules in ancient rocks, found by Curiosity—carbon-based materials that could be building blocks for life or leftovers from non-biological chemistry. 

• A potentially habitable past: long-lasting lakes, rivers, and a thicker atmosphere in early Mars history.

• Current mysteries: methane, odd oxygen behavior in the atmosphere, and those weird dark streaks that still don’t have a perfectly tidy explanation.

NASA and other agencies are very careful here. The bar for “we found life” is insanely high, on purpose. Right now, the official position is “promising chemistry, interesting environments, no confirmed life.”

If you want a well-grounded overview of how NASA approaches the search for life on Mars, their astrobiology and Mars mission pages are a good starting point—they walk through strict protocols, instruments, and what counts as real evidence.

What Happens Next on Mars?

The next big leap is Mars Sample Return—actually bringing rocks that Perseverance is caching in Jezero Crater back to Earth for lab analysis. That’s where the serious instruments live, the ones that can slice a grain of rock thinner than a human hair and still keep asking it questions.

Those samples could:

• Confirm whether ancient lake sediments show chemical fingerprints of past life

• Pin down how fast Mars lost its atmosphere

• Tell us whether those odd organics are biological, geological, or something in between

Meanwhile, every new rover photo, seismic analysis, and atmospheric reading adds another puzzle piece.

Want to Test Your Mars Knowledge?

If you like turning this kind of space mystery into a challenge, you can play a Mars-themed Bing Homepage style quiz on our site and see how much you really remember about the Red Planet’s weird behavior. Try this Bing Homepage Quiz game and see if you can beat the clock while you learn.

Play a Bing Homepage Quiz–style game now

Final Thoughts: A Planet That Refuses to Be Boring

Here’s where we stand:

• We’ve mapped the planet, drilled into its rocks, listened to its quakes, and sniffed its air.

• We’ve solved some mysteries—like those dark slope streaks likely being dust avalanches, not trickles of water.

• We’ve opened even deeper ones—like the mantle “blobs,” the solid inner core, and that stubborn methane that doesn’t behave.

Mars isn’t just “the next place to plant a flag.” It’s a time capsule from the early solar system, a half-finished Earth-like world that froze mid-story.

And for now, NASA’s most honest answer to some of its biggest Martian questions is still: We don’t know yet—but we’re working on it.