00:00Something is happening on the red planet!
00:02Scientists believed that they knew nearly everything about its atmosphere.
00:06But a NASA rover has discovered something unexpected.
00:10There's more oxygen on Mars than they thought,
00:13and it behaves in weird ways.
00:15In the spring and summer,
00:17oxygen levels go up even more,
00:19and no one knows why.
00:22Now, you might think that
00:24when there's oxygen in an atmosphere,
00:26it's mostly because there's life somewhere around.
00:29Like trees on Earth that produce oxygen through photosynthesis.
00:33But on Mars, it's not that simple.
00:36Non-living processes can also create oxygen,
00:40so we can't surely say that its presence means there's life on Mars.
00:46Mars has long been one of the main candidates
00:48when it comes to looking for signs of extraterrestrial life.
00:52Back in the 90s,
00:53scientists announced they had spotted potential proof
00:56there could be life on Mars,
00:58because of microbes they had found in a meteorite
01:01that had arrived from the red planet.
01:03It looked like they had found fossils of bacteria.
01:07They actually stumbled upon tiny crystals of magnetite in the meteorite,
01:11which they believed could only have been produced by living organisms.
01:15It was such a mind-boggling discovery.
01:18People were excited,
01:19but many were also skeptical.
01:22It didn't prove there really was life on the red planet.
01:26Maybe there was life there a long time ago.
01:29The meteorite is thought to have originally formed on Mars
01:32billions of years ago,
01:34and to have landed on Earth thousands of years ago.
01:37Skeptics soon started to pick apart the evidence
01:40and eventually found some things that didn't make sense.
01:44For example, these magnetite crystals.
01:47No one could be sure how they formed.
01:49Why do they have to be bacteria?
01:52Some research has shown they could be the result of shock waves.
01:57Recently, the Perseverance rover has collected a couple of new rock samples
02:02from the Jezero crater on Mars.
02:04The theory says that about 3 billion years ago,
02:07before the red planet lost most of its atmosphere
02:10and basically just dried out,
02:12there was a big lake with a river flowing from it in that area.
02:16Whoa, what a great environment for life!
02:20Perseverance studied mud samples it had found
02:23on the bottom of the evaporated saltwater lake.
02:26Scientists were amazed to see a record number of sulfate molecules,
02:31something we usually find in mollusk shells on our home planet.
02:35Such organisms evolved a couple of hundred million years ago.
02:39But maybe there was a time when some of their space ancestors
02:43lived in water bodies on Mars.
02:46Mars has weaker gravity than Earth,
02:48which means these weird species could have got really big there,
02:53way bigger than their Earth cousins.
02:55Gravity plays a significant role
02:57when it comes to limiting the size of organisms.
02:59Bigger organisms need more energy to move against gravitational forces.
03:04But the creatures that may have lived there long ago
03:07are just a mix of hypothesis and our imagination,
03:11something that's still really hard to prove.
03:15Meet the Curiosity rover,
03:18another robot NASA is using to explore Mars.
03:21Curiosity has been in charge of measuring the composition
03:24of the atmosphere of the Red Planet for many years now.
03:27The rover has discovered that it mostly consists of carbon dioxide
03:31and a little bit of nitrogen and argon.
03:34The atmosphere of Mars has only one-tenth of one percent of oxygen,
03:39since, as far as we know at the moment,
03:41Mars doesn't have plants that could produce enough oxygen.
03:46But Curiosity has also discovered anomalies no one can really explain.
03:51It's found out that there are spikes in oxygen levels
03:54in the Gale Crater during the Martian spring and summer.
03:58Every year, oxygen levels go up and down in unpredictable patterns there.
04:04What's even more interesting is that the oxygen spike
04:07is similar to a seasonal spike in methane,
04:10which is a gas we often associate with life on Earth.
04:14No wonder scientists are scratching their heads
04:17and wondering if there's a connection between the two gases,
04:20and if they both come from the same source on the Martian surface.
04:24Is there something big that breathes there?
04:27Come on, we'll be happy even with some small space worms in the soil.
04:32There's a type of salt called perchlorates in the Martian soil.
04:36Some scientists believe perchlorates might be responsible
04:39for the strange spikes in oxygen levels.
04:41But like with most things we know about space, it's just a theory.
04:46Also, scientists think that perchlorates breaking down in the Martian soil
04:51release oxygen too slowly to cause and explain
04:54the sudden increase in oxygen levels.
04:57One of the suspects is hydrogen peroxide,
05:00which is like water's unstable cousin.
05:03Hydrogen peroxide forms when sunlight breaks up carbon dioxide
05:07and water vapor in the Martian atmosphere.
05:10It can seep into the soil and stick to particles underground,
05:14which means it forms some kind of oxygen storage tank.
05:18Some data even show there are pockets of subsurface water in the Martian soil
05:23that may be hiding enough dissolved oxygen to actually support life.
05:29But even if the hydrogen peroxide could stay in the soil for millions of years,
05:34it would still only explain a small part of the increase in the level of oxygen.
05:38So you can't blame it for the whole thing.
05:41We can also take a look at an old experiment from the 1970s
05:45where scientists found that moistening the Martian soil
05:48caused it to release a lot of oxygen.
05:51However, they did this experiment at a warmer temperature than the planet's average.
05:56And again, it doesn't explain how the oxygen spike keeps happening every year.
06:02None of the clues we have seems to fit the case.
06:07Mars may not have enough of its own oxygen,
06:09but it's possible to make this gas there.
06:12NASA conducted a small experiment where they tried and managed to produce oxygen on Mars.
06:18MOXIE is a device that can make oxygen on Mars.
06:22It managed to produce enough oxygen for an astronaut to breathe for 100 minutes.
06:27This awesome device worked in pretty tough conditions.
06:31At night or during the day, at extreme temperatures,
06:34and during the crazy dust storms the red planet is known for.
06:38Despite all this, MOXIE still kept up with producing high-purity oxygen.
06:44MOXIE is a clever device that can make oxygen on Mars
06:47by taking in carbon dioxide from the planet's atmosphere
06:51and heating it up to incredibly high temperatures.
06:54This allows the device to pull oxygen atoms from the carbon dioxide
06:58and produce breathable oxygen gas.
07:03If we want to use MOXIE to make enough oxygen for human missions to Mars,
07:07we need to make a bigger version of the device.
07:10But if we make it bigger, we might have trouble keeping it at the right temperature
07:15and making sure it heats up evenly without breaking.
07:18The ultimate goal would be to create an oxygen device
07:21that could continuously support a human mission for about 400 days.
07:26With a bigger version of MOXIE, we'd have enough oxygen to support crew members
07:31and even propel a return rocket to our home planet.
07:36When you see the dusty red surface of Mars,
07:39you can't say it's a place that hides liquid water underneath.
07:42Some say it's too cold for water to exist on Mars anyway.
07:46But there are stories that there could be a hidden world of liquid water,
07:51just like subglacial lakes in Antarctica.
07:54And to find out more, we might have to drill down about a mile beneath the surface.
07:59Unfortunately, it's not going to happen anytime soon.
08:05But in the meantime, scientists have been using a spacecraft called Mars Express
08:10to study radar reflections around the southern pole of Mars.
08:14The reflections seem to indicate there could be liquid water,
08:18and the planet's interior might be keeping it warm.
08:21Some claim it might just be rock.
08:23We hope there are underground lakes on Mars,
08:26because it would be a perfect spot to look for life.
08:29After all, scientists have found bacteria living in subglacial lakes on Earth.
08:34But we don't know for sure how deep they are,
08:37or if they're just small veins of water in the ice.
08:41Only time, and more exploration, will tell.
08:49That's it for today.
08:50So hey, if you pacified your curiosity,
08:52then give the video a like and share it with your friends.
08:55Or if you want more, just click on these videos and stay on the Bright Side!
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