00:00Hmm, it looks like a regular beach, but something sets off an alarm blaring in your head.
00:06The sand looks too red, the sun is too bright, the wind is all wrong, it's hard to breathe,
00:12and there's no water in the ocean.
00:14Well, panic not, it's normal, since you're on Mars.
00:18For the longest time, we've seen Mars as a dry, lifeless dust ball, a freezing desert
00:24where water exists only as ice or vapor.
00:27But new research suggests that billions of years ago, it was a totally different place.
00:32And instead of endless dust, it may have had something much more familiar to us, sunny, sandy beaches.
00:40Scientists from Penn State, UC Berkeley, and Guangzhou University studied radar data from China's Zhurong rover.
00:47It started to roll across Mars in 2021.
00:51While exploring the surface of the red planet, it found sloping rock formations
00:55that looked strikingly similar to the ones found on Earth's coastlines.
00:59Those are called foreshore deposits.
01:01They form when waves push sand onto a shoreline.
01:05But Zhurong wasn't just taking pretty pictures.
01:08It also had ground-penetrating radar,
01:10a tool that allowed it to scan deep below the Martian surface
01:13as it traveled 1.2 miles between May 2021 and May 2022.
01:19And it found something pretty wild.
01:22Layers of sediment sloping down at a 15-degree angle.
01:25This pattern is identical to the ones left behind by waves on Earth.
01:30And not, this wasn't from the wind, volcanoes, or anything else.
01:34It just looked like a real beach.
01:36And that's actually a big deal.
01:39Because if there were waves and tides,
01:41there must have been a large body of water.
01:43That means Mars may have once had just the right conditions for hosting life.
01:49Even after 3.5 billion years,
01:52the formations are still incredibly similar to beaches on Earth.
01:55So there must have been a time when Mars was much more than just a dusty rock in space.
02:01After revealing this shocking news,
02:04Zhurong's radar scanned 260 feet deep into the ground,
02:08discovering sediment layers.
02:09They once formed along a path perpendicular to an ancient shoreline,
02:14the one that likely existed 4 billion years ago.
02:17At the same time, it might not be all that surprising.
02:20Back then, Mars wasn't the dry, frozen wasteland we see today.
02:24It had a thicker atmosphere,
02:26a warmer climate,
02:27and plenty of liquid water.
02:29And I'm not even talking about some tiny puddle.
02:32Beaches don't form without a massive body of water.
02:35For waves to shape the land like this,
02:37there had to be rivers flowing into a vast ocean.
02:41Powerful currents had to be moving sand around.
02:44And water had to stick around for a long time.
02:47This couldn't be just a brief wet spell.
02:49It was a period where Mars was hydrologically active for millions of years,
02:54potentially being a place where life could have thrived.
02:57This discovery gives even more weight to one theory.
03:01It has been puzzling scientists since the 1970s.
03:03That's when NASA's Viking spacecraft
03:06snapped images of what looked like a shoreline
03:09wrapping around Mars' northern hemisphere.
03:12But there was a problem.
03:13The shoreline was all over the place,
03:15with elevations varying by up to 6 miles.
03:18Wow.
03:19Which is nothing like our flat,
03:21mostly consistent shorelines we see on Earth.
03:23This difference made scientists doubt
03:25that a Martian ocean ever existed.
03:28For years, scientists had been trying to crack this mystery.
03:31In 2007, they suggested that Mars' rotation
03:35actually shifted billions of years ago.
03:38As the planet's massive Tharsis volcanic region grew,
03:41the planet's spin axis tilted, warping the surface.
03:45It could explain why the shoreline is so uneven today.
03:48In other words, what once was a flat and level landscape
03:51got distorted over time.
03:54Interestingly, Mars has been dropping hints
03:57about its watery past for years.
03:59Curiosity found ancient ripples in Gale Crater.
04:03There were signs of a long-gone lake.
04:05Perseverance is currently studying
04:07a fossilized river delta in Jezero Crater.
04:10Now, with Zurong's evidence of an ancient ocean,
04:13it all comes together.
04:15Small lakes?
04:16Check.
04:16Rivers?
04:17Check.
04:18A massive ocean covering the northern lowlands?
04:20Quite possibly.
04:22Zurong's mission wrapped up in May 2022
04:25after dust blocked its solar panels.
04:28But future missions could still explore
04:30those ancient shoreline deposits.
04:32Scientists might send new missions
04:34to drill deeper into the ground to retrieve samples.
04:37Or we could use better radar
04:38to map Mars' subsurface in more detail.
04:42There's a real hope to excavate those areas in the future
04:45and find even more clues about Mars' past.
04:47At the same time, NASA's Perseverance rover
04:51is already working hard in Jezero Crater
04:53collecting samples.
04:55Scientists hope that it will bring them back
04:57to Earth in the 2030s.
04:59While those won't include samples from the ancient ocean,
05:02they could still help us find out more
05:04about Mars' wetter history.
05:06For now, the discovery of ancient beaches on Mars
05:09gives us a peek into a time
05:11when the planet might have looked a lot more like Earth,
05:14with water, waves, and rivers.
05:16Now, let's speak about the Perseverance rover
05:19that's still working on Mars in more detail.
05:22It has a special drill on its arm
05:24and uses it to scrape off the dust
05:26and top layers of rock,
05:28making small 2-inch-wide circles in Jezero Crater.
05:31Once, one of its cameras took a close-up photo,
05:34and the image showed that the rock wasn't smooth.
05:37It was made of tiny interlocking crystals.
05:40The rover used two special tools
05:42to analyze the rock's chemistry.
05:43The results confirmed that the rock,
05:46named Rochette, was volcanic.
05:48It meant it formed from lava or magma,
05:51not from mud and clay,
05:53like scientists had expected from a former lake bed.
05:56Perseverance, also known as Percy,
05:58landed on Mars in February 2021,
06:01along with a small helicopter named Ingenuity.
06:04It is the most advanced rover ever sent to Mars,
06:07following in the footsteps of Curiosity,
06:10Spirit, Opportunity, and others.
06:12But Percy has a different mission.
06:15While older rovers mainly studied Martian rocks and climate,
06:19Perseverance is searching for signs of past life.
06:22Scientists chose Jezero Crater
06:23because it looks like it used to be a lake
06:25where tiny lifeforms could have lived.
06:28The rover drills, scrapes,
06:30and collects rock samples to study with its science tools.
06:33It also saved some samples to bring back to Earth
06:35in the future for even closer study.
06:38Perseverance has found some surprising things on Mars.
06:42Scientists studying the data it sent back
06:44have discovered that Jezero Crater
06:46has changed a lot over time.
06:48Long ago, this area had flowing lava,
06:51a lake that lasted for thousands of years,
06:54rivers that carried mud and sand,
06:56and even massive floods that brought in rocks from far away.
06:59It means that Jezero's history is more active and unpredictable than scientists expected.
07:06This definitely made it harder to find the sedimentary rocks they were looking for.
07:10But it has also revealed new places where ancient life might have existed.
07:15Another exciting discovery is that every rock Perseverance has studied so far
07:19contains carbon-based materials,
07:22the same stuff that life on Earth is built from.
07:25NASA's Perseverance rover also carries a special tool called MOXIE,
07:30which has managed to make oxygen from the carbon dioxide in Mars' atmosphere for the first time.
07:36Over 16 test runs, MOXIE produced about 4 ounces of oxygen.
07:41That's enough to keep an astronaut breathing for about 4 hours.
07:44It worked even better than expected,
07:46making up to 0.42 ounces of oxygen per hour.
07:50After running successfully for 2 years, MOXIE completed its final test in September 2023.
07:56It brings us one step closer to sending humans to Mars in the future.
08:01In any case, back to the discovery of ancient shorelines on Mars.
08:05This finding might help us see the red planet with new eyes.
08:09Water might have been flowing across its surface for tens of millions of years,
08:13carving out lakes, rivers, and even a vast ocean.
08:16What else have we misunderstood?
08:18Did Martian dinos stroll across the vast green valleys of the planet?
08:23Or were those bizarre marine creatures the likes of which we can't even imagine?
08:27Well, we don't know yet.
08:29But one thing is very likely.
08:31Mars had an era of warmth, water, and maybe life.
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