The Strangest Phenomena Ever Seen on Earth

0:06 The Earth's atmosphere may look empty, but it's really a complex and dynamic

0:11 place swirling with gaseous matter and thermal energy.

0:16 Some of its most spectacular activity is best viewed at night.

0:21 If you've ever watched a lightning storm or a meteor shower,

0:25 the breathtaking Aurora Borealis in the north

0:28 or the shimmering Aurora Orales in the south,

0:32 then you know what an incredible light show the sky can put on.

0:37 But in recent years, with the help of highly sensitive cameras,

0:41 researchers have been able to document a number of unusual,

0:45 previously unrecorded light producing phenomena.

0:49 These occurrences which happen high in the Earth's

0:52 atmosphere are known as transient luminous events.

0:56 What are these strange phenomena?

0:59 Why are they so elusive?

1:01 And what can they teach us about the hidden workings of our atmosphere?

1:07 I'm Alex Mccoan and you're watching Astramm.

1:10 Join me today as we look at incredible images of transient luminous events as we

1:16 explore and unravel some of the most

1:18 mysterious and elusive phenomenon in the night sky.

1:23 Let's begin with a remarkable image.

1:26 It looks like a cross between a lightning storm and a jellyfish, doesn't it?

1:31 This is a red sprite,

1:33 and the formation you're looking at is fittingly called a jellyfish.

1:37 It's incredibly big, spanning up to 50 km and originates at an altitude

1:43 of 70 to 80 km above the Earth.

1:46 Sprites are short-lived events lasting 3 to 5

1:50 milliseconds and they travel downwards at blazing speeds,

1:55 reaching 10% the speed of light.

1:58 For years, sprites were only rumored to exist.

2:02 Reports can be found as far back as the 18th century,

2:05 but a theoretical basis wasn't published until 1925 when physicist CTR

2:12 Wilson speculated that the electrical breakdown

2:14 could occur in the upper atmosphere.

2:17 However, despite years of unverified sightings,

2:21 it would take more than six decades for their existence to be confirmed.

2:26 So, what are sprites?

2:29 Unlike lightning, which is extremely hot, sprites are cold plasma events,

2:35 much like the reaction inside a fluorescent tube.

2:38 Let's think about that fluorescent light for a moment.

2:41 It requires a power source to ionize

2:44 the gases trapped inside in order to emit light.

2:47 As it happens, sprites also require

2:50 an electrical discharge to trigger their fluorescent reaction.

2:54 You see, inside a storm cloud,

2:56 there is friction between rising ice crystals which become

3:00 positively charged and sinking soft hail particles which become negative.

3:06 These positively charged crystals in turn cause a negative

3:10 shield layer to form in the air above them.

3:13 When a positive discharge happens in the form of a lightning strike,

3:17 the cloud becomes neutralized, but the negative shield layer remains.

3:21 We now believe it is this unstable,

3:24 negatively charged shield layer that causes electrical

3:27 breakdown in the upper atmosphere, producing sprites.

3:32 It is even possible that sprites aren't especially rare.

3:36 What makes them incredibly difficult to observe is that they occur high

3:40 in the ionosphere where they are often

3:43 hidden by the storm systems that produce them.

3:46 So, to see a sprite, you need a clear sight line over

3:50 a thunderstorm or perhaps a camera positioned above it.

3:55 As you can see here,

3:56 the International Space Station was lucky enough to get one in action.

4:01 Sprites glow red because under the low pressure conditions where they originate,

4:06 nitrogen emits low frequency red light where its molecules get excited.

4:11 Compare this to auroras, which are usually green.

4:14 That's because at the higher elevation where auroras occur,

4:18 Earth's atmosphere has greater levels of oxygen

4:20 whose molecules fluores green when they get excited.

4:24 But sprites don't always produce red light.

4:28 Sometimes a sprite will set off a secondary event at a lower elevation.

4:32 These secondary events, or tendrils, often appear blue.

4:37 While their light is also produced by nitrogen,

4:40 the higher pressure causes them to glow blue and near ultraviolet.

4:45 As a result, some larger sprites, like the jellyfish we saw earlier,

4:49 have a remarkable appearance, glowing red at the top and blue at the tentacles.

4:56 Sprite tendrils aren't the only tle's with a bluish tint.

5:00 This event is known as a blue jet.

5:04 Discovered only recently,

5:05 blue jets are a distinct phenomenon also initiated by storm systems.

5:11 In these events, the positive charge at the top of a storm

5:14 cloud forms a leader with a negative shield layer above the cloud,

5:18 producing a discharge that propagates upwards.

5:22 This excites the nitrogen, making a spectacular cone-shaped jet that glows blue.

5:29 Why blue?

5:30 Well, remember what we said about

5:32 how atmospheric pressure affects excited nitrogen gases?

5:36 Blue jets occur much lower in the atmosphere than sprites,

5:39 which is why they flues a different color.

5:42 There are also smaller TLEs called blue starters,

5:46 but scientists believe they are simply failed blue jets.

5:50 These dimminitive cousins only reach 20 km above the Earth.

5:55 At the other end of the family is

5:57 a separate phenomenon known as the gigantic jet and it

6:00 occurs much higher in the atmosphere which is why

6:03 the upper portion changes color from blue to red.

6:07 We'll leave today with one of the rarest and least understood tle.

6:12 These green or red phenomena are known as elves.

6:16 A quaint acronym that stands for a mouthful.

6:20 Its full name is emission of light and very

6:23 low frequency perturbations due to electromagnetic pulse sources.

6:27 Try saying that five times fast.

6:30 Unlike sprites and jets, elves are diffuse ring-shaped phenomena

6:35 that occur even higher in the atmosphere.

6:38 And unlike what the name suggests, they are huge.

6:43 Elves can grow up to 400 km in diameter and occur 100 km above the Earth.

6:50 But despite their size, they are extremely short-lived events.

6:54 They only last a millisecond, so brief that they can't be seen by the naked eye.

7:00 While little is known about elves,

7:02 we believe they are caused by an electromagnetic

7:04 pulse produced by the discharge of an underlying thunderstorm.

7:09 So, there we have it.

7:10 An introduction to some of the most spectacular transient

7:14 luminous events that have been confirmed in recent years.

7:18 What other luminous phenomena may be lurking in the Earth's atmosphere?

7:22 It's tantalizing to think about,

7:24 and because this is still a fairly new field of research,

7:27 we can only imagine what new surprises may be in store for us.

7:32 Want more videos about weird atmospheric phenomena on Earth?

7:36 Let me know in the comments.

7:41 Picture the ocean on a dark and windy day.

7:48 Rather than smooth rolling waves,

7:50 the surface is rough and choppy with deep troughs and frothy crests.

7:56 Now, imagine that stormy ocean flipped upside down and blanketing an entire sky.

8:03 It may sound crazy, but that image

8:06 is a pretty close approximation of aspiritus clouds,

8:09 an extremely rare cloud type that was only

8:12 recognized by the World Meteorological Organization in 2017.

8:17 Aspiritas, which translates to rough and uneven,

8:21 is one of the rarest cloud forms on record and the only one

8:25 to have been formally added to the WMO's cloud atlas in almost 70 years.

8:31 Given how recently they were discovered,

8:33 not much is known about how or when aspiritus clouds form,

8:37 although we have some theories.

8:39 So, what makes Aspiritus clouds different?

8:43 Why haven't we noticed them before?

8:46 And could their discovery provide a blueprint

8:48 for identifying extremely rare weather events in the future?

8:54 I'm Alex Mccoen and you're watching Astramm.

8:57 Join me today as we look

8:58 at spectacular highdefinition images of aspiritus clouds.

9:03 Learn what scientists think could be

9:05 giving them their dramatic appearance and explore

9:08 the exciting implications of this unusual

9:11 convergence of citizen science and trailblazing research.

9:17 In 2006, Jane Wiggins, an amateur photographer located in Cedar Rapids, Iowa,

9:23 took a photo from her office window

9:25 that she described as looking like Armageddon.

9:29 She sent the image to the Cloud Appreciation Society,

9:32 which posted it on their website.

9:35 The photo immediately set off shock waves among cloud watchers,

9:39 who suspected that it could be evidence of a previously unknown cloud formation.

9:45 Other amateur hobbyists using the Cloud Spotter mobile

9:48 app started sharing their images with each other,

9:51 sharing weather conditions to look out for to help others see it for themselves.

9:55 This caught the eye of the Royal Meteorological Society,

9:59 which used dozens of photos collected by the Cloud Appreciation Society

10:03 to prepare a case that they sent to the World Meteorological Organization.

10:09 After several years of debate, the WM made an announcement.

10:14 For the first time since 1951,

10:17 they were adding a totally new type of cloud to the cloud atlas,

10:21 giving aspiritus clouds the unique distinction of being the only cloud

10:25 type to have been discovered as a result of digital crowdsourcing.

10:30 But why was this rare?

10:32 And who decides what makes a cloud form unique?

10:37 Let's start with a primer.

10:39 Clouds essentially are liquid droplets or solid particles

10:43 suspended in the atmosphere of a planetary body.

10:46 While on other planets, clouds can be made of methane,

10:50 ammonia, or even sulfuric acid.

10:53 Here on Earth, the vast majority contain liquid or frozen water.

10:57 And personally, I'm glad we don't have many of the sulfuric acid variety.

11:02 Clouds form when saturated air reaches its due point.

11:06 The temperature at which under a given set of barometric conditions,

11:11 water vapor condenses into liquid due to cooling

11:14 air or increased saturation from an adjacent water source.

11:18 There are five primary cloud types.

11:21 Stratus, cumulus, stratouulus, cumuloneimbus, and cirrus.

11:26 Each of which are subdivided into different genre based on altitude.

11:31 However, in addition to these primary categories,

11:34 there is a range of accessory clouds which are clouds that become

11:38 detached from the original genus clouds as well as supplementary features.

11:44 All of these are formally classified in the W cloud atlas,

11:48 the international manual for cloud identification,

11:52 which uses a linear nmanllete that has been in place since the 19th century.

11:58 The WMO is responsible for updating the cloud atlas,

12:01 but revisions are extremely rare.

12:04 The last new formation was Sirrus in added back in 1951.

12:10 Now, aspiritus clouds are thought to be

12:13 mostly a supplementary feature of stratapform clouds,

12:17 which are low elevation layered clouds without vertical development.

12:21 Although, aspiritus have also been observed to be stratouulus or altocumulus.

12:27 Interestingly, while the bases of the stratapform clouds are generally flat,

12:32 they tend to develop significant features

12:34 at the top due to wind and temperature changes.

12:37 This is extremely common and something you will no doubt be

12:40 familiar with if you've looked out of the window of a plane.

12:44 What makes aspiritus clouds unusual is

12:46 their highly developed structures at the bottom.

12:51 In 2017, researchers from the Cloud Appreciation Society, University of Reading,

12:56 and McGill University published a paper attempting to describe

13:00 the features and causes of aspirus cloud formation.

13:04 According to the authors, aspirus clouds are defined by their rough,

13:08 somewhat wavelike cloud base that lacks the smooth

13:12 undulating shape of the possibly related unulitus cloud type.

13:17 Given these semi-wavelike characteristics,

13:20 the authors hypothesize that aspiritus clouds

13:23 are likely created by weak ocilitary activity.

13:27 There are a few potential causes of this.

13:30 One is orography, which is the wavelike movement

13:33 caused by the flow of air over mountainous terrain.

13:36 However, there could be other reasons such as horizontal wind shear, convection,

13:42 which is the exchange of matter or temperature between fluid bodies,

13:46 or atmospheric gravity waves.

13:49 By the way, in case you're wondering,

13:51 a gravity wave isn't the same as a gravitational wave.

13:55 As much as I love space-time physics,

13:57 we're not talking about massive ripples in the space-time fabric here.

14:02 A gravity wave occurs at the border between

14:05 one fluid and another when a force upsets

14:08 the equilibrium and gravity tries to restore it which

14:11 produces a back and forth movement or wave orbit.

14:16 Some familiar examples of gravity waves include tsunamis and the changing tides.

14:21 You have probably seen the result of gravity

14:23 waves affecting clouds too and julitus clouds.

14:27 I'm sure you've noticed cloud formations like this before from a ground view.

14:32 The view from space is equally spectacular.

14:36 But aspiritus clouds have an appearance of roughness

14:39 that indicates unusual instability at the cloud base.

14:43 These aren't smooth and wavelike like

14:45 the unjulitous cloud type we've just looked

14:47 at, but have a formation that is chaotic

14:50 like the stormy ocean we talked about earlier.

14:53 While stratapform clouds often have what is

14:56 known as Kevin Helmhalt instability at the top,

14:59 an instability that comes from velocity shear within fluids,

15:03 this instability is more unusual at the base of clouds.

15:07 So what might be the cause?

15:10 We don't know yet.

15:11 But the authors of the 2017 paper from earlier suggest

15:15 that this instability may propagate downward from the top of the cloud,

15:19 which could happen if the cloud is thin enough.

15:22 Perhaps there are different reasons each time.

15:25 The scientist who captured this time lapse said that here gravity

15:29 waves were moving through an inversion

15:31 underneath an elevated region of instability.

15:35 You've probably seen an inversion before where clouds or even

15:38 smog is trapped under a layer of hotter air.

15:43 Thunderstorms were in the forecast,

15:44 but the thunderstorms could not pull their inflow

15:47 air from near the surface due to the inversion.

15:50 So instead they pulled from above the inversion.

15:54 The gravity waves moving through the inversion

15:56 created enough lift that a strong updraft

15:59 was formed and it moved in phase with the peak of the gravity wave.

16:03 This enhanced lift from the updraft increased the amplitude

16:06 of the wave and made the aspiritus cloud here very visually impressive.

16:12 Regardless of how it happens, this internal instability appears to disrupt

16:17 the weak ocilitary activity at the base,

16:19 resulting in the rough, choppy appearance.

16:22 So, when you think about it,

16:24 the winds and currents causing the choppiness of the ocean on a stormy day

16:28 aren't that unlike the chaotic forces scientists

16:31 think are producing instability in an aspiritus cloud.

16:35 In both cases, complex fluid dynamics are in play,

16:39 giving rise to eerily similar characteristics.

16:42 Nature may not repeat itself, but it often rhymes.

16:48 So, there you have it.

16:49 A primer on one of the newest and least understood cloud types on record.

16:54 If this interests you, you might want to keep watching the sky

16:57 and taking photos of anything interesting you see.

17:00 Who knew we'd still be discovering new cloud types?

17:04 What else out there don't we know about?

17:06 And who knows, you could be part of the next scientific breakthrough.

17:13 When it comes to talking about the universe,

17:16 I'm not usually at a loss for words.

17:19 But every so often, I see something so awe

17:21 inspiring and unusual that words don't do it justice.

17:26 And it seems that when I posted an image of this last year,

17:29 it looks like I'm not alone here.

17:31 Such is the case with noctalucent clouds,

17:34 a strange and beautiful phenomenon that occurs high in the Earth's

17:38 messosphere and requires a unique set of conditions to form.

17:43 In fact, these cloud formations are so

17:45 captivating that they've inspired communities of watchers

17:49 who share atmospheric data online in the hope of seeing one for themselves.

17:55 So, what are Noctalucent clouds?

17:58 What gives them their ghostly luminescence?

18:01 And what surprising insights can they offer?

18:04 Not just about Earth's atmosphere, but perhaps the future of our planet.

18:10 I'm Alex Mcolen and you're watching Astramm.

18:13 Join me today as we view spectacular

18:15 images of these eerily beautiful cloud formations.

18:19 Learn how they form and understand why they are

18:21 giving scientists a surprising window into Earth's changing atmosphere.

18:27 Imagine a clear summer night.

18:30 The sun has dipped below the horizon

18:33 and Capella is shining brightly to the north.

18:36 Suddenly, a bright streak erupts low in the northern sky.

18:41 It might look like a shining silver thread or perhaps an icy blue whirl.

18:47 Slowly, the streaks get brighter and clearer until finally

18:52 the whole sky glistens with a patchwork of eerily shining clouds.

18:57 Night shining clouds such as this formation

19:00 photographed over the Baltic Sea are truly spectacular.

19:05 And no, they don't actually emit light.

19:08 They get their glowing appearance by reflecting solar

19:11 radiation during astronomical twilight when the sun is

19:14 between 6 and 16° below Earth's horizon

19:18 and remnant light is scattered in the upper atmosphere.

19:22 Because noctalucent clouds form at very high altitudes

19:26 around 76 to 85 km above the terrestrial surface,

19:30 they can reflect the sun long after an observer has fallen into Earth's shadow.

19:35 So while noctalucent clouds also form during daylight hours,

19:40 they are only visible to the unaded eye at night.

19:44 To make a noctal cloud, you need water,

19:48 dust particles, and incredibly low temperatures.

19:52 Unlike normal clouds which form in the Earth's troposphere where 75%

19:57 of the atmosphere's mass and 99% of its water vapor occurs,

20:02 Noctalucent clouds form high in the upper meosphere

20:06 which is the atmosphere's third layer above the stratosphere.

20:10 Just a reminder, the lowest layer of atmosphere on the Earth is the troposphere.

20:16 the boundary of which is the tropopores.

20:18 Then the stratosphere, stratopes, meosphere, meopor,

20:23 thermosphere, thermopor, and then finally the exosphere.

20:28 For more about all these layers, check out this video.

20:32 The mesosphere is a tricky region to study since it's too high

20:36 for spacecraft to fly and too low

20:39 for orbital spacecraft due to atmospheric drag.

20:42 Noctalucent clouds form slightly below the mesopor which is

20:46 the upper boundary between the mesosphere and the thermosphere.

20:50 The meopor is also the coldest region

20:53 of earth with temperatures that can plummet below 100°.

20:58 By comparison, the coldest temperature ever recorded in Antarctica was- 89.6°.

21:06 These frigid conditions produce tiny ice crystals less than

21:10 100 nanome in diameter which then gather on dust particles.

21:15 Researchers have learned that the meosphere must reach

21:18 -20° C for these ice crystals to form.

21:22 That's pretty cold.

21:24 But if noctalucent clouds require such cold conditions,

21:27 why do they occur during summer?

21:30 Well, one unusual property of the meopor is

21:34 that it is colder in summer than in winter.

21:37 Known as the meoporal,

21:40 this happens because hot air in the lower troposphere expands resulting

21:44 in upswelling gases that decompress in the meosphere causing adiabatic cooling.

21:51 Because noctalucent clouds require very low temperatures,

21:54 they only appear for 60 to 80 days out of the year,

21:58 peaking around 20 days after the solstice.

22:02 If you want to see a night shining cloud formation,

22:04 you'll need a lookout spot between plus or minus 50 and 70° latitude.

22:11 Although satellites have spotted many meospheric clouds

22:14 north of the 70th parallel, here on Earth,

22:17 the polar regions have too much ambient

22:19 light during the summer for optimal viewing.

22:22 So, if you happen to live in northern Norway or Alaska,

22:25 you'll have to travel south for your noctal cloud watching.

22:30 That's a pretty good survey of what we know.

22:33 So, let's talk about what we don't.

22:37 Saying the meosphere is a very dry place would be a bit of an understatement.

22:41 In fact, it is 1 million times drier than air from the Sahara Desert.

22:46 Not exactly a place you'd expect to find clouds.

22:50 We currently think upswelling air from the troposphere

22:53 is the likely cause of this moisture.

22:55 More puzzling, however, is the question of where the dust is coming from.

23:00 One theory is that it comes from space in the form of debris.

23:05 The Earth gets bombarded daily with thousands

23:07 of meteorites and other space debris.

23:10 Could they leave enough dust to create such massive cloud formations?

23:14 Or could there be other causes?

23:17 Interestingly, Noctalucent clouds were first cited in 1895,

23:22 2 years after Crackatoa's massive volcanic eruption in Indonesia,

23:26 which spew debris into the upper atmosphere.

23:29 It has to be something big like this because otherwise the atmospheric layers

23:33 don't mix very much and so dust wouldn't usually make it to the meosphere.

23:39 We also know that man-made sources such as exhaust

23:42 from space shuttles can sometimes trigger no clouds

23:46 such as a 2014 incident when the Space

23:49 X Falcon 9 caused no clouds over Orlando, Florida.

23:54 In 2009, the United States Naval Research Laboratory successfully created

23:59 an artificial noctalucent cloud using exhaust

24:03 particles from a suborbital sounding rocket.

24:06 And in 2018, the University of Alaska created

24:09 a noctal cloud by releasing water from a suborbital rocket.

24:14 But without such proximate causes, the source isn't easy to pinpoint.

24:19 Luckily, NASA has launched a satellite known as the Aeronomy of Ice

24:24 in the Meosphere or AIM to answer these and other pressing questions.

24:29 It was first launched in 2007, but as of 2022 is still operational.

24:36 AIM is powered by two solar panels

24:38 and is equipped with three payload instruments.

24:41 The cosmic dust experiment,

24:43 which emits pulses to measure speeding dust particles.

24:47 The cloud imaging and particle size has four cameras that image

24:52 meospheric clouds from variable angles to create a detailed 2D panoramic view.

24:58 And the solar occultation for ice experiment,

25:01 which measures particles, temperature,

25:04 and atmospheric gases in order to identify

25:06 chemicals and conditions for noctalucent cloud formation.

25:10 There have also been several experiments to synchronize

25:13 Ames observations with those of low-flying aircraft.

25:17 The first of which was conducted in July 2009.

25:20 By synchronizing data between satellites and aircraft,

25:24 scientists can construct far more detailed models of meospheric cloud

25:28 formation and their features than they could from aim alone.

25:32 For NASA and other atmospheric researchers,

25:35 answering these questions is no idle matter.

25:38 The messosphere is a remarkably sensitive indicator

25:41 of changes that are happening elsewhere in the atmosphere.

25:44 The same features that make it so unusual,

25:47 its rarified gases and sensitivity to changes far down in the troposphere,

25:52 make it a useful canary in the coal mine, so to speak.

25:56 Decades of noctalucent cloud study have made

25:58 it clear that they are becoming more frequent,

26:01 and climate researchers are now beginning to link

26:03 changes in noctalucent cloud distribution to global climate change.

26:08 As the troposphere gets hotter,

26:10 the messosphere visav the mesopor's anomaly may well be getting cooler

26:16 and improving our understanding of the mesosphere

26:18 has other farreaching implications as well.

26:21 It is a vital part of the atmosphere for re-entering spacecraft.

26:25 And because the meosphere is so dry and low density,

26:29 studying it could help us learn about atmospheres on other planets such as Mars.

26:34 By deepening our knowledge of the mesosphere,

26:36 researchers hope not only to understand the properties of noctalucent clouds,

26:41 but also Earth's atmosphere as a whole and how it is changing over time.

26:49 They are watching you.

26:52 Ever feel that prickle across your neck?

26:55 That ominous sensation of eyes on you, but you can't detect anyone around?

27:02 Well, although they can't spot the culprit directly,

27:06 your senses might be onto something.

27:09 The Earth is surrounded by eyes studying you, tracking you,

27:16 trying to understand every aspect of your dayto-day life.

27:21 They are our own satellites, and there are hundreds of them,

27:26 and I don't think we have quite realized how good they've gotten.

27:32 There are satellites with mirrors the size of Hubbles,

27:36 not pointed at distant galaxies to unravel their mysteries,

27:39 but staring down at you.

27:43 There are satellites that can see through clouds

27:46 and don't care if it's day or night.

27:48 They see just as clearly either way.

27:52 In this age of information where companies are pushing for more

27:56 and more data and governments strive to keep track of criminals and threats,

28:02 the thing that might be harder and harder to find is privacy.

28:07 Are the benefits worth the cost?

28:13 I'm Alex Mccoan and you're watching Astramm.

28:16 And it is time to look out the nearest window and smile for the camera there.

28:22 Now, do you want to see how your picture turned out?

28:29 In 1957, the number of artificial satellites

28:33 in space first ticked up from zero to one.

28:37 Sputnik 1 was launched by the Soviet Union officially to practice

28:41 their satellite deployment methods and to send

28:44 test radio signals through the atmosphere,

28:47 but also to show the world that they were winning the space race.

28:51 The world, however, did not take long to catch up.

28:54 In 2007, 50 years later, there were 912 active satellites orbiting the Earth.

29:02 As a testament to how quickly the industry is growing,

29:06 it took only 10 years for that number to reach 1,778.

29:11 In 2022, the number hit 6,95 and this number is set to grow.

29:21 The company SpaceX alone wants to eventually raise

29:24 the number of active Starling satellites to a whopping 42,000.

29:30 In the next 10 years, there could be hundreds of thousands of satellites

29:34 from various different countries and private organizations orbiting our planet.

29:39 Of course, not all of these satellites are there for observation.

29:43 around half of the ones active right now are communication satellites.

29:48 But still, according to data collected by the UCS,

29:52 the aptly named Union of Concerned Scientists,

29:55 at the start of 2022, there were 1,052 eyes looking down on us.

30:02 That's a lot of eyes, and they're getting sharper.

30:08 Let's discuss spatial resolution.

30:10 This is a measurement of how many meters on the ground

30:13 are represented by a single pixel in a satellite taken image.

30:18 The early cameras on satellites like LANCAT 1 had a resolution of 80 m,

30:23 which is to say a single pixel represented an 80x 80 m square,

30:28 meaning you could almost fit an entire football field in it.

30:32 This made them good for taking sweeping images of our planet at large

30:36 and perhaps for keeping track of massive objects like clouds and weather fronts.

30:40 But there was hardly the sense that our privacy was at risk.

30:44 Now, well, see for yourself.

30:48 These full color videos were taken by Carbonite 2,

30:53 a commercially available satellite that captures an entire 5 km swath

30:58 as it passes by at 500 km in low Earth orbit.

31:03 The resolution for this video is 1 m,

31:06 which is good enough that you can pick out details like the motion

31:09 of waves on the sea or cars driving along the road in real time.

31:16 Although you might not be able to distinguish

31:18 their car make and most likely not their drivers,

31:21 the advantages of such a video are obvious.

31:25 Transport officials can keep an eye on traffic congestion

31:28 and it becomes easy to track the speed of urbanization.

31:31 There are also numerous scientific benefits which we'll get into later.

31:36 But there's one undeniable feature of such improved resolution

31:40 that made it very interesting for governments around the world.

31:44 And the main reason you might be worried,

31:47 it becomes easier for spy satellites to keep track of you.

31:54 Spy satellites have also come a long way.

31:58 Originally, when the CIA began their secretive corona project,

32:02 disguised as an innocent space exploration program called Discoverer,

32:07 satellite cameras were recording their images onto actual film,

32:11 which then had to be jettisoned and parachuted back down to Earth,

32:14 where the capsules carrying the sensitive data could later be recovered.

32:18 One of these capsules was actually the first

32:21 ever man-made object to be recovered from space.

32:24 It wasn't the most efficient system and spy satellites tended not to last

32:28 longer than a year before they ran out of film and capsules.

32:32 Now everything is digital,

32:35 significantly improving the lifespan of such satellites.

32:39 As for what they can see, well, for obvious reasons,

32:43 governments tend not to reveal how good

32:45 the resolution is on their spy satellites.

32:49 However, it's interesting to note that the video I showed you earlier of the 1

32:53 m resolution satellite camera is not the best the market has to offer.

32:58 Other satellites boast 50 cm and even 25 cm resolutions and some

33:04 such as Umbra SAR satellite claim to have reached 16 cm.

33:10 And this is only about as good as they are legally allowed to get.

33:14 The United States has laws in place that make

33:16 it illegal to have satellites with better resolutions than that.

33:20 Although companies are pushing for this restriction to be lowered so that they

33:24 can keep up with a competitive global

33:26 market that doesn't always have such restrictions.

33:30 Take a note of that though.

33:31 This is not about capability.

33:34 True, the laws of physics put some constraints on us that make better

33:37 resolutions difficult to impossible without having

33:40 a satellite fly close enough to the planet

33:42 that atmospheric drag will start to cause it to fall or without making a light

33:47 gathering mirror so large that it becomes difficult to launch them on a rocket.

33:52 However, it's not accurate to say

33:54 that spy satellites can't get better resolution.

33:58 There are rumors of resolutions hitting at least

34:00 10 cm resolution, perhaps even 1 cm.

34:05 Rumors that were at least partially confirmed by the previous

34:09 US President Donald Trump by accident in a tweet he posted.

34:14 In 2019, Iran attempted a rocket launch that ended in failure.

34:19 Trump felt it was necessary to tell the world that the US

34:22 government had not been involved in sabotaging the rocket launch.

34:25 To prove his point, he included a photo of the damaged launch site,

34:29 hoping to show that there were no signs of foul play.

34:33 This may well have been true,

34:34 but intelligence experts around the world were stunned

34:38 at the crisp detail included in the image.

34:41 After analysis, it was revealed that the image

34:44 had to have been at least 10 cm resolution, perhaps even better.

34:49 Let's get a feel for what an image better than

34:52 10 cm resolution might look like on a regular high street.

34:57 This is the bit where you might need to wave to the camera.

35:01 This image is not a satellite image,

35:03 but was taken by a plane flying over the town of Zurich.

35:08 However, it does reveal what a better than 10 cm resolution image can show.

35:14 We are no longer on the resolution of making out cars.

35:17 Here you can see the branches on trees, even the color of clothes on people.

35:23 You can see a lot of detail.

35:25 Can you imagine what a 1 cm image might look like?

35:30 This represents technology that exists today.

35:34 In fact, better technology is now out there.

35:38 The satellite that took this is a keyhole 11 spy satellite.

35:43 A keyhole 12 already exists,

35:46 which amateur astronomers have managed to image in spite

35:49 of official pictures naturally not being released to the public.

35:53 We don't know the resolution on this one,

35:56 but it has dimensions similar to the Hubble telescope.

35:59 And one of the reasons Hubble used the mirror size that they did was

36:03 because they realized they could use the same

36:05 supplier as the US Department of Defense.

36:10 So there are potentially 11 additional Hubbles out there.

36:16 Imagine how much further we would be if

36:18 they were used for science instead of spying.

36:22 We are also no longer in an era

36:24 where cloud cover or nighttime can ensure privacy.

36:28 Synthetic aperture radar imaging is capable of piercing

36:31 through clouds as the technology doesn't collect visible light,

36:35 but instead sends down a radar pulse and then

36:37 times how long it takes to bounce back.

36:40 Done enough times over a wide area with some sensitive equipment to discern

36:44 the different times taken of different parts of the wave to return.

36:48 SAR satellites can form detailed physical models of the ground and can

36:52 even simulate having a much larger mirror than they can actually carry.

36:57 Because they are not reliant on natural light but are sending their own pulses.

37:01 These types of satellites can work during the night as well as the day.

37:07 So with all of this, you likely are

37:10 starting to feel a little worried for your privacy.

37:13 It's unsettling to think that at any time you step out the house,

37:17 eyes could be on you, watching you walk or drive to your destination,

37:21 seeing who you meet, where you go.

37:24 They are probably not able to read your phone screen, but that's not far off.

37:29 The cost of privacy feels huge.

37:32 If you live in a city like London,

37:34 you may have been thinking this anyway with the number of cameras around,

37:37 but even where there are no cameras, you aren't safe.

37:42 However, it should be pointed out that satellites with decent resolution,

37:46 although probably not at the 10 cm mark,

37:49 can be extremely beneficial for studying our planet.

37:53 It's hard to list the benefits in full, but they include weather monitoring,

37:57 studies of our climate, including sea level rises,

38:01 CO2 levels in our atmosphere, tracking aerosol emissions,

38:04 and seeing the current dimensions of the ice sheets,

38:07 tracking surface temperatures, crop health, irrigation use, water quality.

38:13 You can even use precise satellites with cloud

38:16 penetration to see the hot spots on wildfires,

38:19 giving firefighters a better chance at tackling blazes.

38:22 or we can better understand hurricanes,

38:24 atmospheric dust clouds, and other disasters.

38:28 In one incredible application, a NASA satellite intended to study cyclones was

38:33 used to track locust swarms across eastern Africa, mapping out the most fertile,

38:39 water- richch areas that locust like to lay

38:41 their eggs in or feed in during their juvenile forms.

38:45 In so doing, they helped reduce swarms in Kenya in 2019,

38:50 which was incredibly beneficial to farmers

38:52 and the people whose food they supply.

38:55 Perhaps the bit that feels uncomfortable is if it seems like

38:59 the people watching us do not have our immediate benefits at heart.

39:04 Studying the planet feels like a positive and worthy goal,

39:07 and accurate data is helpful in that.

39:10 However, it's also undeniable that businesses across the world would

39:15 love to keep track of where people are shopping, population trends,

39:19 and other metrics that allow them to better sell to customers,

39:22 which is a goal you're less likely to want to sacrifice your own privacy for.

39:27 Monitoring might help city planners to keep

39:30 track of the flow of traffic on roads and get a better sense of where

39:33 to build relief roads or other helpful interventions.

39:36 Spy and law enforcement agencies also, in fairness, do a lot of good.

39:41 They stop terrorism and catch criminals.

39:44 But it's scary to think that once the technology is here,

39:48 if ever the government in possession of it

39:50 decides to use it for more invasive goals,

39:52 there's not much that can be done to stop them.

39:58 At the end of the day, perhaps this is something inevitable that we

40:02 will all simply have to get used to.

40:04 it's difficult to stop the flow of progress.

40:07 As long as there are advantages to better resolutions on satellites,

40:11 people will want to pursue developing them.

40:14 In any case, it's at least good to know just how effective it's

40:18 all becoming because then your decisions on the matter can be informed, too.

40:22 You can decide whether this is becoming something that makes

40:25 you nervous or something you aren't really bothered about.

40:29 Whether this needs tighter regulation through

40:31 lawgivers or whether it is a necessary

40:33 cost to be paid for the ease and security of modern life.

40:37 Wherever you stand on this matter, best put a brave face on.

40:41 Smile.

40:42 After all, you never know who is watching.

40:49 Imagine 100 nuclear bombs going off at the same time.

40:54 This was the equivalent force of hunger

40:56 tonga hunga haipe which produced the most atmospheric

40:59 disturbance ever recorded by modern instruments and the most

41:03 powerful eruption since the 1883 Krakatoa eruption.

41:07 The shock wave from it created a pressure wave

41:09 that traveled around the globe at least four times.

41:13 And although it wasn't audible for all of that time,

41:16 it was heard as far away as New Zealand, Australia, and Alaska.

41:22 Just one of the aftershocks sounded like this.

41:26 It caused the tsunami and devastated the volcanic island it was situated on.

41:31 The ash and dust blanketed Tonga and was

41:34 carried through the stratosphere across vast distances.

41:38 Fortunately, eruptions like this are rare,

41:41 but it just goes to show nature's fury should not be underestimated.

41:45 Imagine you're at home or at the office when

41:48 the walls of the room you're in start shaking violently.

41:52 Books fall off the shelves.

41:54 Cabinets threaten to topple over.

41:56 You quickly realize this is an earthquake.

42:00 And then you look up and it occurs to you

42:02 that there is another entire story of building above you.

42:06 As the walls continue to wobble, you know that should they fall,

42:10 that roof above you is coming down and you stand a good chance of dying.

42:15 So you look up as the quake goes on and on and you wonder, will it hold?

42:21 Will it hold?

42:23 When you see the footage from the Japan

42:25 2024 Noto Peninsula earthquake that struck

42:28 in the afternoon on New Year's Day when families were gathered in their homes,

42:32 it's easy to envision the fear that must

42:35 have been felt by those who experienced it.

42:38 This was a deadly tragedy with 241 people killed and 1,296 injured.

42:46 In spite of its relatively small size,

42:49 Japan is the country with the fourth largest number

42:52 of major earthquakes in the world over the last few decades.

42:56 Our planet Earth is frequently shaken by earthquakes.

43:00 But there are things about Norto that make it

43:03 different from any other earthquake that we've seen before.

43:09 I'm Alex Mccoan and you're watching Astramm.

43:12 And today we'll be entering a world

43:14 of earthquake swarms and changes to the Earth's rotation.

43:19 Of earthquake shake tables carrying buildings 10 stories high

43:23 and a geological mystery that remains unsolved to this day.

43:34 It's no wonder that Japan is regularly impacted by earthquakes.

43:38 Japan sits on the western edge of the Ring of Fire,

43:42 one of the most tectonically active places on Earth.

43:45 These vast plates of rock and soil constantly

43:49 and inexorably shift over the course of millions of years,

43:53 sometimes pulling apart and sometimes moving together.

43:57 To further complicate matters,

43:58 Japan sits along the edge of multiple smaller plates at once.

44:03 The Pacific plate pushes west and subducts or slides

44:07 underneath the Philippine Sea plate and the Okhatosk plate.

44:12 But the Amuran plate also pushes up

44:14 against the Okhatosk plate while the Philippine

44:17 plate subducts underneath the Amuran plate

44:20 and the smaller Okinawa plate at the same time.

44:23 It's a complex geological wrestling match,

44:26 one which led to the formation of the islands of Japan in the first place,

44:30 but one that also causes a lot of friction and tension beneath the surface.

44:35 What happens when the forces of play become too much

44:38 for the friction that holds it back and things slip?

44:42 That's when you get earthquakes.

44:45 However, in the case of the Japan January

44:47 2024 earthquake that struck in the Nto Peninsula, it caught locals by surprise.

44:53 Why?

44:54 Because Noto is not actually on one of the major fault lines,

44:59 and scientists are not yet quite sure why earthquakes are even happening there.

45:05 If you map out the location of earthquakes

45:07 by depth and location over the last 25 years,

45:10 you can see that they congregate mostly on the eastern side

45:13 of Japan where the Pacific plate subducts under the Ohatosk plate.

45:18 You can even see how earthquakes that are

45:20 further west are also triggered deeper beneath

45:23 the ground representing the fact that the subducting

45:25 plate has moved further underground with the additional distance.

45:29 But rather than striking on the eastern side of the island,

45:33 the January 2024 earthquake hit NTO to the west.

45:38 There are other peculiarities.

45:41 Strange things have been happening beneath Notto over the last 3 years.

45:46 Since 2020, Nto has been experiencing tens of thousands of small

45:51 earthquakes in a geological event known as an earthquake swarm.

45:57 But counterintuitively,

45:59 this consistent rumbling is normally not something to worry about,

46:03 as several small shakes are better than one big one,

46:06 and earthquake swarms generally die out

46:08 quietly rather than producing large earthquakes.

46:12 Noto's earthquake swarm bucked the scientific models,

46:16 lasting too long and producing

46:18 the exceptionally powerful January 2024 earthquake,

46:22 and scientists do not really know why.

46:31 The consequences were serious.

46:34 The January 2024 earthquake was a magnitude 7.5 and struck at 10 400 p.m.

46:40 Japanese time on New Year's Day when people were gathered in their homes.

46:46 It was not just one event,

46:48 but hit with a number of force shocks and aftershocks.

46:52 1,200 of them that ranged across an area over 150 km across.

47:00 At least seven were magnitude 5 or higher.

47:04 40,000 homes immediately lost power.

47:08 Roads cracked.

47:09 Buildings collapsed.

47:11 The Japanese government quickly issued a tsunami

47:13 warning across the west coast of Japan.

47:16 The first waves of which arrived just 1 minute later in Suzu.

47:20 A wave as high as 5 m was expected.

47:23 Although most of the footage captured is a wave of only 1 to 2 m high.

47:29 Certainly the force was enough that buildings along the coast were swept away.

47:34 All told, there were hundreds of deaths and over a thousand injuries

47:39 across six prefixures and over 18 billion US dollars in property damage.

47:45 The train itself bucked and rose.

47:49 One strange feature of notto is that there

47:52 has been an unexplained upswell that has

47:54 been taking place there beneath the crust

47:57 since the earthquake swarm started in 2020.

48:00 The edge of the peninsula has risen by about 3 cm since then,

48:04 indicating something was gathering down there.

48:08 Perhaps water, perhaps magma.

48:10 Scientists aren't really sure.

48:13 When the earthquake itself hit, however,

48:15 that's when the peninsula really started to rise.

48:19 Some sections of the land rose as much as 4 m.

48:23 And you can see the effects in these satellite images.

48:26 The change in the land's elevation altered where the sea met the shore,

48:30 pushing the coastline back 250 m,

48:34 leaving some ports completely cut off from the water.

48:38 And when this much land moves,

48:40 it can influence the rotation of the planet itself.

48:45 Changing the distribution of mass on the planet's

48:47 surface changes how quickly it spins.

48:50 In the same way, a ballerina pulling her arms in will rotate faster.

48:54 In 2011, the magnitude 9 To<unk>hoku earthquake in Japan shortened Earth's

49:00 day by 1.8 micros secondsonds or 1.8 millionth of a second.

49:06 It's not much.

49:08 And other effects such as differing sea

49:10 levels also change the Earth's rotation speed.

49:12 But it's amazing to see how interconnected the planet is.

49:16 An earthquake in Japan can affect the entire world.

49:20 No matter where you are,

49:21 your life was imperceptibly altered by the Notto earthquake.

49:30 With all of this, it is no wonder that scientists across

49:34 the globe are working hard to understand the causes of earthquakes.

49:38 But for those who live under their constant threat,

49:40 such as for the people in Japan,

49:42 or other countries like Indonesia, China, or Iran,

49:46 it's also important to defend against their consequences.

49:50 So in an effort to improve their architectural

49:52 design to make them more earthquake resistant,

49:55 Japan's National Research Institute for Earth Science and Disaster Resilience

49:59 has taken steps such as developing the world's largest earthquake simulator,

50:05 effort supports buildings as tall as 10 stories and can use real

50:14 life data to simulate the most

50:15 devastating earthquakes Japan has ever experienced.

50:19 By testing different designs in the different types of earthquake scenarios,

50:23 architects have been able to design braces,

50:26 beams, and metal joints that reinforce traditional Japanese houses,

50:30 making them more earthquake resistant.

50:32 It can be the difference between

50:34 a building staying upright or collapsing entirely.

50:39 Interestingly, NASA's space program indirectly helped

50:42 with creating earthquake resistant buildings in Japan.

50:45 Consider the Tokyo Skytree, the world's tallest tower at 634 m.

50:52 A place I saw with my own eyes once when I was visiting Japan.

50:57 Given the risk of earthquakes in Tokyo, it was vital that engineers designed

51:01 a building that could withstand large shakes.

51:04 They did so using a central 360 m

51:08 tall concrete column that sits on four massive rubber

51:12 bearings which attaches to the building around it

51:15 using fluid dampeners developed during the NASA Apollo program.

51:19 When an earthquake strikes,

51:21 these fluid dampeners cause the central column to sway

51:24 at a different rate to the exoskeleton of the building around it.

51:27 The different rhythms of motion counteract each other,

51:31 reducing the motion in the building overall.

51:34 Incredibly, these effects can reduce the force of earthquakes by up to 50%.

51:44 Earthquakes can carry a terrible cost

51:47 in lives and destroyed homes and livelihoods.

51:51 For the Noto Peninsula,

51:53 the people there have slowly begun the task of rebuilding their lives.

51:57 Although the broken roads initially made it difficult

51:59 for emergency services and repair workers to get around,

52:03 power has been restored to the majority of the 40,000 homes that were affected.

52:08 Although as of March 2024, 790 still were without electricity.

52:14 18,880 were without water and 11,400 people

52:20 were still in evacuation shelters in Ishikawa Prefecture.

52:25 Earthquakes are overwhelming examples of the natural

52:28 force that exists beneath us at all times.

52:32 They can shatter cities and recovering from them is a slow task,

52:36 but it speaks to the hardiness and determination

52:39 of the people who make places like Japan their home.

52:42 They seek to find solutions to powerful earthquakes to predict

52:45 them and to mitigate their damage with clever engineering.

52:50 This can help us all.

52:52 Through studying the processes that take place beneath our feet,

52:56 we can better navigate this world that we live on in a way that helps us thrive.

53:01 The world is dangerous, but also beautiful.

53:04 And like life, its face is ever changing.

53:08 It's up to us to face that change

53:10 until we can overcome any disaster that befalls us.

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