Documentary, Horizon - The Wildest Weather in the Universe
#WildestWeather #Universe
#AncientEarth #Documentary
#WildestWeather #Universe
#AncientEarth #Documentary
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00:00we all love talking about the weather is it too hot or is it too cold is it too
00:12wet or too windy it's a national obsession but now scientists have also started looking to the
00:20heavens and wondering what the weather might be like on other planets we're witnessing the
00:29birth of extraterrestrial meteorology as technology is allowing astronomers to study the weather on
00:36other planets like never before sugar has these very long-lived storms but Saturn has these very
00:46violent storms but incredibly today the latest telescopes are enabling astronomers to find and
00:54study planets beyond our solar system so here we have our image of Roxas 12b which is pretty
01:03amazing to think that we are imaging a planet 400 light-years away and our exploration of the
01:09universe is revealing alien worlds with weather far stranger and more extreme than anyone could
01:16ever have imagined a lot of the planets that we're studying so far are very horrible places you
01:25wouldn't want to go there on vacation on these planets you can get the most gigantic storm systems
01:33ever witnessed by mankind so one side of the planet can be roasting hot while at the same time the other
01:40side of the planet can be freezing cold we thought we had extreme weather on Earth but it turns out
01:55that it's nothing compared to what's out there so instead of having rain which is liquid water droplets
02:03like here on Earth it would be raining liquid rubies and the search for the weirdest weather in the
02:10universe is only just beginning
02:12it's a delightfully warm spring morning in Greenwich London astronomers of all ages have
02:33gathered at the Royal Observatory where they're hoping to witness a rather special event they're
02:39waiting to glimpse another world and unusually for astronomers they've got their telescopes out
02:46during the day we're here to see quite a rare astronomical event I'm very excited to see it I'm
02:54just hopeful as we all are that the clouds don't come along around midday and stay with us it's a
03:02chance to get a unique perspective of one of our nearest neighbors
03:05and to take a closer look astronomer Tom Kurz has set up the great equatorial telescope to look at
03:17the Sun for the first time since 1927 because at exactly 12 minutes past noon the planet Mercury is due to
03:28the past in front of the Sun
03:30so here is Mercury emerging onto the face of the Sun looking very beautiful indeed over the next seven and a half hours or so Mercury will gradually slink across the face of the Sun and as it overtakes us on the inside track in the solar system about 50
03:35million miles away from the earth right now
03:59from the earth right now ever since we've known about the existence of other
04:05planets we've wondered what these mysterious alien worlds might be like
04:12could they be potential homes for life and is there any way of finding out
04:21so I'm wondering whether other planets might be habitable or not the key
04:26questions that we need to ask to begin with is what is the atmosphere actually
04:29like what is the climate like what's the weather like whether it be very extreme
04:33or whether it be quite pleasant and stable the kind of weather that we think
04:36is necessary for life so what will the weather be like on mercury if we look
04:43back at the beginning of the mercury transit we can see a really clean bite
04:47taken out of the Sun and the edge is so clean because mercury doesn't have any
04:52appreciable atmosphere to speak of with no real atmosphere mercury is
05:01effectively a dead and barren world because mercury lacks anything that we
05:07would call an atmosphere there's essentially no weather on mercury at all
05:10mercury is unusual in our solar system because all the other planets do have atmospheres and so they
05:26must also have weather death valley california one of the most extreme and alien environments on earth
05:37planetary explorer Suzanne Smircar has come here because it shares a surprising
05:43similarity to our nearest neighbor Venus Venus is the brightest object in the
05:49night sky and the reason it's so bright is because it's covered in thick clouds and
05:55when you turn your telescope to it you can see nothing of the surface all you see is
06:00this bright reflection coming back at you because of the cloud deck that's kept it
06:04now shrouded in mystery we do know that Venus is similar in size to earth is a rocky world like
06:12our own and also relatively close to us so what's its climate like we think that Venus was much like
06:19the earth maybe 50 degrees hotter because it's that much closer to the Sun we thought it had an
06:24atmosphere like the earth we thought it would be cool enough to have oceans we even thought it was
06:31it was covered in steamy hot swamps probably covered with verdant green life
06:36but to discover what Venus was really like we needed to go there
06:45at the dawn of the space age people started to explore it was it was the cold war in the 60s and the
06:55soviets in the US were you know setting spacecraft after spacecraft trying to be the first out
07:00there a huge number of spacecraft have been hurled at Venus and there are many attempts to get to the
07:06surface in the late 1960s the Russians succeeded the one that finally made it to the surface was
07:14venera 7 in 1967 and that probe felt gently through the atmosphere got to the surface and survived for
07:22only about two hours before they died the venera probes revealed the true nature of Venus's climate
07:34Venus has a surface temperature of 462 celsius which makes it the hottest place in this solar system
07:43and the atmospheric pressure on Venus is almost a hundred times that on the earth
07:47with surface temperatures hot enough to melt lead an oppressive atmosphere of carbon dioxide
07:57and belching clouds made of sulfuric acid Venus is a planetary vision of hell
08:09we knew for the first time that Venus is not a swampy verdant region teeming with life but instead
08:15it's a hellish hot inferno Venus is the hottest planet in the solar system but it's not the closest to the Sun
08:27soo has come to Death Valley where the unbearable temperatures are created by the same phenomenon at work on Venus
08:40we're here today in Death Valley the hottest place on earth the temperature today is 42 degrees
08:48pretty balmy for Death Valley the highest recorded temperature is 57 degrees so we have it easy today
08:55the reason it is so hot here is that we're at 86 meters below the sea level and that means that we
09:02have about 86 meters more atmosphere here and that means it's higher pressure and in fact the pressure
09:09measurement here is 1016 bars and that extra bit of pressure is really what's giving us this intense heat
09:18that we're experiencing today it's like adding another layer of insulation or another blanket that's holding the
09:24heat in
09:32and by simply driving uphill sue can reveal the tremendous insulating power of the atmosphere
09:43now we're at about a thousand meters and it's already looking greener and a bit cooler up here
09:48at Dante's view almost two kilometers above the valley floor the temperature is much cooler
10:04we're at about 1.7 kilometers above the valley floor where we were earlier today and the temperature
10:10is 30 degrees celsius way cooler than the 42 degrees down there and the reason it's so much cooler up
10:17here is that we have that 1.7 kilometers less air our pressure is 831 bars down below it was a thousand
10:27sixteen so the pressure is much lower we have a lot less atmosphere above us and as a result it's much
10:34cooler much cooler much more pleasant up here on earth the temperature typically increases by about
10:446.5 degrees celsius for every kilometer you descend
10:48on venus with its much deeper atmosphere than earth this insulating effect is taken to its extreme
11:04it is so much hotter on venus because the pressure is at 92 bars
11:09almost 100 times out on the earth and the atmosphere is much thicker much denser and it really holds that heat
11:15and making venus the incredible inferno that it is on top of this venus's atmosphere is almost entirely
11:23made up of the greenhouse gas carbon dioxide and this combines with the intense pressure
11:31to make venus the hottest planet in the solar system
11:34our next nearest neighbor couldn't be more different venus and mars are like chalk and cheese
11:48so mars is the opposite extreme from venus its atmosphere is one one hundredth the pressure of
11:54earth's and the effect of having that really low atmospheric pressure on mars means that
12:00uh it can't trap any of its heat so mars is a cold barren desert compared to earth or to venus
12:09because of its thin atmosphere mars is home to some spectacular weather phenomena
12:16the rovers sent by nasa revealed that mars is scoured by supersized dust devils
12:22reaching up to a kilometer in height
12:30but even more impressive are the dust storms which dwarf those on earth
12:36in the thin atmosphere of mars the dust storms can get to a very high elevation they can get to about
12:4220 kilometers above the surface
12:43and because most of mars is a dry dusty desert these dust storms can cover vast expanses
12:55in fact it seems there is no limit to how far they can spread
13:01every few years an enormous dust storm will grow until the entire planet is engulfed
13:07incredibly storms like these have been shown to envelop the whole of mars for over two months
13:25further out in the solar system the weather gets even wilder
13:31it's another fine sunny day in pasadena home of nasa's jet propulsion laboratory
13:36andrew ingersol is the father of extraterrestrial meteorology
13:44he's come to the deep space operations center
13:47it's mission control for the small fleet of spacecraft that nasa has sent to explore the outer reaches of
13:53the solar system
13:56andy has worked on all these missions
13:59so we've had a whole series of spacecraft visiting the giant planets
14:06the first big one was voyager in the 70s which zoomed past all the giant planets
14:14then there was galileo then the cini which has been in orbit around saturn for 10 years
14:21and now we have juno in orbit around jupiter the spacecraft have given us an unprecedented view of
14:31the weather on these planets the outer planets are big balls of gas and that makes a huge difference in
14:39the weather so there's lots of room for weather and because you don't have continents you don't have
14:46mountains for the winds to rub against and there's nothing to control the weather the way the
14:54continents partly control our weather this means these planets have storms on an entirely different
15:00scale to ours and the most famous storm of all has to be jupiter's great red spot
15:07the great red spot is a huge storm in jupiter's atmosphere you could put two earths inside the
15:15red spot and the winds going around the periphery of the red spot are about three times the speed of
15:23the earth's jet streams with winds whipping round at about 650 kilometers per hour and releasing so much
15:33energy that it heats the atmosphere above it to around 1400 degrees celsius the red spot has been
15:40raging for as long as we on earth have been able to observe jupiter shortly after galileo built the first
15:49telescope people were using these primitive telescopes to look at jupiter and they saw this storm
15:56and uh it's apparently been there ever since which is remarkable compared with earth storms the red spot
16:05has been there for over 350 years and that makes it the longest living storm that we know of
16:17jupiter may have the longest lasting storm but it's saturn the next gas giant that is home to the
16:23the largest and most powerful storm ever seen in the solar system and in 2010 the cassini spacecraft was
16:31there to see it saturn of course is a spectacular sight because of the rings and it's also rather
16:41boring as far as the weather is concerned it's a bland thing but every now and then 20 30 years
16:50saturn erupts with a giant storm and cassini was fortunate to be orbiting saturn at the time of one of
16:59these eruptions what happened was on december 5th 2010 the radio receiver on cassini started picking up the
17:11radio signal of lightning and on the same day the camera saw a little storm up in the northern hemisphere
17:20of saturn by january it had developed into a fair sized thing and then we watched it for six months
17:33during that time the huge storm grew and wrapped itself around the entire planet
17:38covering four billion square kilometers until its head caught up with its tail
17:47driven by winds going at around 1 800 kilometers per hour with huge lightning flashes
17:5310 000 times stronger than those we get on earth
17:56it's very funny jupiter has these very long-lived storms but saturn has these very violent storms
18:07we don't fully understand why there's this difference in the weather between jupiter and saturn
18:12whether it's duration or size the storms on both these planets dwarf those on earth
18:17however because they receive far less heat from the sun than the earth does something else is also
18:27powering their weather the weather on jupiter and saturn comes from two sources one is the sun
18:34as on earth and the other is the internal heat left over from when the planets formed
18:39it's this internal heat trying to escape through their deep atmospheres that makes the gas planets so tumultuous
18:47the storms on the gas planets are certainly weirder and wilder than any we have on earth
19:05but when it comes to the clouds and the rain things get even stranger
19:10it's a typical june morning in southern california and a local weather phenomenon known as the june gloom
19:21makes it the perfect day for taking a closer look at the clouds
19:30dr kevin baines has a passion for the skies on earth and beyond and he's been studying the clouds
19:37on the gas planets cirrus 599 about mike's coming out of socal we're gonna make a left turn on alpha
19:43and taxi over the runner barrier of the runway one
19:52so in the planet you'll get clouds at different levels depending on the local temperature and the
19:56local pressure on earth all clouds are made of water so in southern california we have this marine layer
20:04what happens is it actually forms over the water the pacific ocean of course has a lot of water
20:10so during the day it heats up and releases water into the air as water vapor and as this water vapor
20:16rises it cools and then it condenses out as water droplets in the air and when you get millions and
20:23millions of water droplets it forms a cloud clouds will form wherever it gets too cold for water to stay as
20:30as a vapor in the air and if there's enough moisture the cloud droplets grow in size until they're big and
20:39heavy enough to fall as rain jupiter and saturn also have a layer of water clouds
20:50if we were to transport ourselves magically to jupiter or saturn we could find a water layer like this
20:57but other substances form clouds at colder temperatures so above the layer of water clouds
21:03higher up in the atmospheres of jupiter and saturn there are two more cloud layers as you climb up out
21:10of the water layer it gets so cold that you get first you get ammonia hydrosulfide which is a very exotic
21:15cloud made of both ammonia and sulfur put together and then as you climb up even higher into the atmosphere
21:22when it gets down to about minus 130 degrees celsius there ammonia gas in the atmosphere condenses out
21:29and form clouds so on these planets it doesn't just rain water there could also be a light rain of liquid
21:37ammonia now if you go out to uranus and neptune it is so cold out there about minus 300 degrees that
21:46uh now you even have methane gas come out as clouds and so on uranus and neptune liquid methane could
21:54fall from the sky bizarre as they are ammonia and methane aren't the weirdest rains of all
22:04because back on saturn in the depths of its atmosphere kevin believes that an astonishing process
22:11is at work that creates what could be the strangest rain in the solar system
22:21this process can be witnessed on an idyllic summer day in oxfordshire
22:28inside this unremarkable office building a manufacturing company is replicating the conditions
22:34deep in saturn's atmosphere not to study it but for industrial purposes using these massive presses
22:43they're turning carbon graphite into something far more valuable
22:49and kevin has come over from california to see how this process can help explain what's happening deep
22:55inside saturn we know that on saturn there's carbon soot we know that by looking at these dark clouds that
23:03we saw with our camera on board the cassini spacecraft in orbit about saturn and we see the spectroscopic
23:09signature of carbon soot there the carbon soot is created by lightning lightning actually zapping
23:15methane in the atmosphere something very strange then happens to the soot as it falls through saturn's
23:23atmosphere it is transformed into something remarkable a process that is actually being replicated here
23:33what we do effectively is we take this carbon graphite we mix it with several other materials
23:39and we assemble what we call a capsule we take that capsule graphite material inside it and we place
23:46it inside the actual press itself the press is then closed up and the carbon graphite is exposed to extreme temperatures and pressures
23:56high pressures are generated by these anvils that compress down onto the graphite pressures of around
24:0450 000 atmospheres and the graphite is then going to be heated to about 2 000 degrees celsius that heating
24:11happens by large electrical currents this process mimics what's happening inside saturn we know we have carbon
24:19which is very much like the graphite that we just put into the machine over here the carbon precipitates or
24:24falls through the atmosphere and eventually it'll get to the 7 000 kilometer level at that point it'll
24:30be experiencing the pressures and temperatures that we experience in the press over here
24:35inside the press the intense heat and crushing pressure transform the carbon from graphite into diamond
24:43all right so this may not look like diamonds but we will then take this rubble and we'll process it further
24:54and we'll extract the diamond great so the diamonds are in there somewhere somewhere inside this rubble kevin
25:00there are diamonds this high temperature high pressure process can make a variety of diamonds which are used in industry
25:15here we have tiny triangles effectively these are used for wire drawing dies and you get square
25:29shaped diamonds which in this case are used as single crystal cutting tools
25:35these diamonds are yellow because they contain nitrogen
25:38so what we were making earlier today effectively are these diamond grits
25:44tiny little stones a single crystal diamond it's nominally about 100 microns in size
25:51kevin believes the same thing is happening on saturn
25:56so we really think it's very similar conditions very similar process that's happening
26:00and at the 7 000 kilometer level in saturn carbon soot will transform itself
26:04into diamonds creating a diamond rain
26:09as the carbon soot falls from the clouds the extreme temperature and pressure deep in the atmosphere
26:15turn it into diamonds
26:20so inside saturn we have a huge region of diamond rain
26:28our exploration of the other planets in our solar system
26:31has revealed weather stranger and more powerful than anything we have here on earth
26:39but what about beyond our solar system
26:42what is the weather like in the rest of the universe
26:49some of those showers could be quite heavy there'll be some dry spells in between but
26:53limited brightness and it will be a cool one
26:55uh... perched at the top of mauna care in hawaii 4 000 meters above sea level is the kek observatory
27:03one of the pre-eminent earthbound telescopes for finding planets orbiting other stars known as exoplanets
27:14brendan bowler has one of the best jobs in the world
27:18he's an exoplanet explorer
27:19i feel incredibly lucky studying astronomy and contributing to exoplanetary science
27:27it's humbling in many ways to be able to contribute and answer some of the questions that we've been
27:34thinking about as humans for millennia
27:38the aim of my job is to find planets orbiting other stars which is a very difficult task to do
27:45planets are both much smaller much lower mass and much fainter than the stars that they orbit
27:54so trying to find planets in the glare of their stars is very difficult
28:00so it's as if we're trying to find a firefly buzzing around a spotlight
28:05that's 10 billion times brighter than that firefly from a distance of new york all the way to london
28:15so how do you find a planet orbiting a distant star let alone study its weather
28:23there are two indirect methods that we primarily use to find planets the first is the radio velocity
28:29technique let's say this is the planet and the post is the star that it's orbiting
28:35as a planet orbits its star the planet exerts gravitational influence on the host star
28:42which causes the host star to wobble so we can search for planets by looking for the back and
28:49forth wobble the planets induce on their host stars and that's exactly how the first exoplanet orbiting a
28:57sun-like star was discovered in 1995 changing the face of astronomy forever
29:03and since then planet hunters have discovered thousands more orbiting distant stars
29:14but planetary explorers aren't satisfied with simply finding planets but what we really want
29:21to do is to be able to characterize the planet in more detail the radial velocity method only tells us
29:28about the mass of the planet the bigger the wobble the bigger the mass but luckily there's a second
29:35technique for finding planets known as the transit method which reveals a whole lot more the transit
29:42method you can think of as a planet crossing between us our line of sight and the star that
29:49it orbits just like this now when that crossing event occurs it will cause a dip in the brightness of
29:55that host star so we can use that to find planets by searching for periodic dips in the brightness of that star
30:07crucially the transit method also tells us how big the planet is because the bigger the planet the
30:15greater the dip in the light from the star the transit method tells us about the size of the planet while
30:21the radial velocity tells us about the mass of the planet so we can use both of those together to
30:28measure the density of planets because density is mass over volume and this reveals what the planet is
30:36made of small dense planets are rocky whereas large planets that are not dense are gas giants
30:45the first planets discovered were huge gas giants like jupiter and since then planet hunters have
30:54found all sorts of combinations of size and mass including small dense planets rocky worlds that could
31:02have atmospheres but finding out any more detail about an exoplanet's atmosphere climate and ultimately its
31:12weather is extremely difficult
31:18but not impossible the key to doing this is the fact that different gases absorb light at different
31:26wavelengths
31:30so we can study the composition of the atmospheres of exoplanets by breaking up the light that we
31:36receive at earth into its constituent colors this is what we're doing here with a projector which emits
31:41white light we're dispersing it with the prism spreading out the light we can see the various
31:47wavelengths and colors that it split into if we have a gas intervening between the projector and the
31:54prism then the different colors will be blocked out depending on the nature of the gas so what i'm going
32:00to do is put a gas in this beam of light by burning baking soda which is sodium bicarbonate
32:05so here we have our baking soda we'll drop a little bit of that into the flame
32:16and so what we're doing is making the equivalent of an atmosphere of sodium atoms in the beam which is
32:22absorbing some of the light and what we see on the spectrum is a narrow dark line that comes and goes as
32:28i drop it in in the yellow part of the spectrum which corresponds to the wavelength that sodium absorbs
32:35every chemical has its own unique pattern of absorption lines
32:42so astronomers can use this information to detect the different substances in the atmospheres of planets
32:49and that's exactly what brendan is going to try to do tonight
32:54he's pointing the keck telescope's awesome light gathering power at a newly discovered planet
33:02i'll be using the keck telescope to study a planet about 400 light years away
33:08its name is roxas 12b it has a mass between 10 to 15 times that of jupiter and we know it's a gas giant
33:16but we don't know what it's made out of which is the goal of our observations
33:19by studying the light that's emitted from this planet we'll be able to learn about
33:24the chemical composition and physical properties of its atmosphere
33:33roxas 12 is about to rise we have two more minutes
33:37it's below the telescope limits but it's about to go up and then we can slew to it
33:41we're trying to look in the infrared to both image the planet and get a spectrum of it and when we
33:50can get a spectrum of the planet we can learn what's in its atmosphere
33:56direct imaging of distant planets like this is at the very cutting edge of astronomy
34:02it's incredibly difficult to image planets but for the most massive planets like roxas 12b it emits
34:10enough light that we can actually detect the photons so we can see the planet and take pictures of the
34:15planet and for this we need our very best telescopes keck is the biggest telescope in the world and so we
34:25need the size of the mirror which is 10 meters in diameter to gather enough photons incredibly the
34:33keck telescope also compensates for interference from our own atmosphere
34:40stars twinkle because of turbulence in the earth's atmosphere we don't like that twinkling we want it to
34:46stop and so we we use adaptive optics to actively compensate in real time thousands of times per second
34:53for that turbulence it's as if we're putting these big telescopes that we have on the ground in space
35:02so far only a handful of planets have ever been directly imaged like this
35:08martin what are the coordinates 16 26 28.1 can you go to roxas 12 and the moon and look how it
35:17looks in the tracks so let's see it finished and then we're ready this is our sixth attempt to get
35:24this target we've been weathered out we've had instrument issues and we think we're finally going
35:31going to get it tonight okay so i think we have the target centered up in the field of view here
35:40i think we can start exposing
35:42so here we have our image of roxas 12b so this is an infrared image of this planet which is pretty
36:01amazing to think that we are imaging a planet 400 light years away
36:05roxas 12b is one of only 15 exoplanets to have ever been directly imaged
36:16and incredibly the faint light captured in this picture will reveal the secrets of roxas 12b's
36:22atmosphere the first step towards understanding its weather we're looking at the infrared light from this
36:29planet this is light that's emitted in the interior of the planet that passed through its atmosphere
36:35and whatever chemicals molecules atoms are in the atmosphere will induce absorption features in the
36:42spectrum and that's what we're looking for so here we can actually get a spectrum in real time and
36:48let's go ahead and do it so here's our spectrum of roxas 12b in the infrared and what we're looking for
36:57our absorption features from carbon monoxide co so we can see these two dips here in the spectrum
37:06which correspond to the wavelengths where co absorbs and that means that this planet really does have
37:11carbon monoxide in its atmosphere the spectrum also revealed that this exoplanet has water vapor
37:19iron hydride fanadium oxide potassium and sodium in its atmosphere fairly typical for an exoplanet
37:27so by studying the light from exoplanets hundreds of light years away astronomers are able to detect
37:33what's in their atmosphere
37:35a key ingredient that goes into creating their weather
37:50later today a mixture of brighter spells and showers for the majority as well as being able to detect
37:56the gases in a planet's atmosphere scientists can also use the infrared light to work out just how hot
38:03a planet is
38:08it's a blustery day in california and exoplanet meteorologist heather knudson is visiting santa
38:15monica pier so the main thing that determines the temperature of a planet is the distance that it
38:22is from its host star planets that are really close in are going to be boiling hot planets that are further
38:27away will be a little bit cooler by comparison most of the exoplanets discovered so far are close to
38:35their stars so scientists expected them to be hot but they didn't know how hot so we can actually go and
38:42measure the temperature of these planets by measuring their brightness and infrared light
38:46hotter things are going to glow more brightly at infrared wavelengths cooler things are going to be a
38:50little bit dimmer and fainter so probably the hottest planet that we know of is a planet called wasp 33b
39:01wasp 33b is the hottest planet discovered so far in the entire universe it's a gas giant
39:09four and a half times the size of jupiter its atmosphere is a scorching 3 200 degrees celsius
39:19so this planet is hot for two reasons one is it's very close to its host star the other reason is that
39:24it orbits a star which is bigger and hotter than the sun both those things together combine to make this
39:30one of the hottest planets that we've discovered planets like wasp 33b are nicknamed hot jupiter's and
39:40they don't just have extreme temperatures because being close to their star has another important
39:47effect on the weather so all planets spin on their axis just like i am now the earth spins once every 24
39:56hours but not all planets spin at the same speed there are some planets which we're discovering which
40:02are very very close to their stars they're so close that the star tugs on the planet as it spins around
40:08on its axis and the tugging of that star actually slows the planet's rotation down keeps slowing it down
40:16and keeps slowing it down until the planet rotates at exactly the same speed that it orbits
40:23so the same side of the planet always faces towards the star just like i'm always facing the center of
40:27this ride here so we call this tidal locking and it means that the planet has a permanent day side
40:34and a permanent night side and being tidally locked has a dramatic impact
40:43so whenever you have one part of a planet that's hot and another part that's cold
40:47the natural result is that you get a wind moving from one part to another here at the beach during
40:53the day the land heats up but the sea stays relatively cold and so you get this nice wind
40:58moving from the ocean towards the land that's trying to even out the temperatures
41:02so when we first discovered these very close in planets we realized that they were probably close
41:07enough to be tidally locked and one of the very first things we wanted to know is what that meant
41:11for the planet's atmosphere so did it mean that these planets had a boiling hot day side and a freezing cold
41:17night side or were there winds in the atmosphere that were able to carry some of that heat around
41:21to the night side to find out heather mapped the temperature on a hot jupiter
41:32which scientists think is blue in color the particular planet we decided to look at was a hot
41:38jupiter called hd189733 now that's kind of a mouthful but i can tell you that this is actually my
41:44favorite hot jupiter this was one of the very first planets that i looked at when i was a grad student
41:49by looking at it in infrared heather was able to measure its temperature
41:55so this is the map we made so the color tells you the temperature of different parts of the atmosphere
42:00so here on the day side things are relatively hot so the day side is about 900 degrees centigrade
42:07here on the edges that's the night side and that's a relatively cool part of the atmosphere it's only
42:12700 degrees centigrade which is still really hot that difference is actually much smaller than we
42:18expected and the fact that it's so small suggested to us that this planet must have strong winds
42:23circulating through its atmosphere and carrying that hot air from the day side around to the night side
42:31incredibly these winds have now been measured directly
42:34and it turns out that hd189733 b is home to the fastest winds in the universe
42:44which rage around it at about 8 700 kilometers per hour seven times the speed of sound and 20 times
42:53faster than the fastest winds ever experienced on earth
42:59showers some of them have sleet in snow elsewhere fewer showers and uh here the showers will be of
43:05rain drier brighter weather it's a beautiful tropical morning on the big island in hawaii
43:13and exoplanet expert hannah wakeford is taking to the skies to explore another bizarre effect
43:20the extreme heat on exoplanets has on their weather the strangest thing about exoplanets is the clouds
43:29and the rain they're nothing like we have here on earth spectroscopy has revealed that exoplanets
43:36have clouds and also what these clouds might be made of we know that exoplanets have clouds if we
43:42have a planet that we know should be gaseous because of its density but we don't detect any spectral
43:46signatures from that gas then we think there must be clouds in the way which are blocking that light
43:51and obscuring our view and sometimes we can detect signatures directly from those clouds by the way
43:57that they scatter or reflect the light but these aren't clouds we'd recognize
44:09a lot of the exoplanets that we've been able to follow up are very hot over a thousand degrees
44:14so we know that water can't exist as a liquid at those temperatures so they're not going to be
44:18clouds like we have here on earth
44:23we're in a cloud so on some exoplanets the clouds will be made of far more exotic substances
44:33temperatures are such that substances that we think of as solids on earth can actually exist as
44:38liquid of gas in exoplanet atmospheres we can get a glimpse of this on earth in volcanoes where
44:47temperatures can reach over a thousand degrees celsius down there is the crater of poo-oo-o-o and you can
44:56see the lava bubbling away the temperature of this lava lake is around a thousand degrees and all of the rock
45:04has melted the metals and minerals and the silicates that make up the earth's crust have all become molten
45:12it's amazing you can really feel the temperature from the lava lake all the way up here it's it's really
45:18very hot it's a thousand degrees melting the earth's crust down there so it's no surprise
45:26but it's these substances that are thought to make up the clouds on some exoplanets
45:35there's a planet called 55 cancri e that we think is rocky because of its density but it orbits very
45:41close to its parent star and it's tidally locked so temperatures on the day side should be high enough
45:47to melt the rock making it a lava planet 55 cancri e is a lava planet while its night side will be
45:59relatively cool and solid rock its day side is an ocean of permanently molten lava on the day side the
46:07temperatures go over 2500 degrees this is hot enough to vaporize the rock and the surface this can then
46:15be lifted into the atmosphere and condensable clouds of liquid lava droplets that then could be transported
46:23to colder parts of the planet where they'll rain down as pebbles on the surface
46:27so on some planets it rains rock rather than water like it does here in hawaii
46:50back on the ground on kilauea hannah has an example of what rock rain might be like
46:57right here was the site of a massive eruption all along this fissure fountains of lava shot into
47:07the air nearly a hundred meters high the liquid lava droplets then cooled and solidified in the air
47:14before raining down onto the surface as these tiny pebbles and sometimes we get these perfect little
47:21droplets called pelle's tears this is what we think the rain might be like on planets like 55 cancri e
47:40but perhaps the strangest rain in the entire universe has been discovered on a giant gas planet which orbits
47:48a star hundreds of light years away we've been able to study the exoplanet wasp 12b and the way that
47:57it scatters light suggests that there are clouds high up in the atmosphere at this part of the atmosphere
48:03the temperature is around 2000 degrees so the most likely substance forming these clouds is an aluminium
48:09oxide called corundum which forms the basis of rubies so instead of having rain which is liquid water
48:17droplets like here on earth it would be raining rubies
48:28we're only just witnessing the birth of exoplanet meteorology
48:32but so far what astronomers have discovered on exoplanets is even more extreme and bizarre than anything
48:40anyone had imagined
48:49compared to what's out there
48:51the most extreme weather on earth are hurricanes and tornadoes
48:55our rain and our snow all seem pretty mild
48:59our climate and weather is actually very hospitable
49:02the earth is a nice place and that's all because of the weather
49:07we've got warm temperatures not too hot not too cold it's a great place
49:13ultimately the planet hunters of the world are hoping to find one thing
49:18another earth
49:18a small rocky planet with a thin blue line encircling it a planet with a nice climate
49:27a climate that could be hospitable to life
49:31what we're really looking for is rocky terrestrial type planets with an atmosphere around them which is
49:37habitable
49:39we'd like that planet to be at the right temperature to have liquid water
49:43so that means being at just the right distance from your stars
49:47and having exactly the right kind of atmosphere
49:51but so far astronomers have mainly found planets with extreme environments
49:56planets with ruby rain or lava clouds
50:00so the planets that we've found so far aren't particularly nice places to go
50:04they're not somewhere you'll put on your vacation list anytime soon
50:07because at the moment it's easier to both find and study the bigger planets
50:13when you're looking at other stars it's easy to find the large planets like jupiter and saturn
50:19where you don't have the right kind of atmosphere
50:22or ones that are close to their stars
50:24our surveys are really good at finding planets that are very close to their stars
50:27which means mostly the planets that we've discovered are much too hot to host life
50:32as we know it on earth
50:33just over 20 years ago astronomers began finding exoplanets
50:39the first were giant hot jupiters orbiting close to their stars because they were the easiest to spot
50:46and now hundreds of smaller rocky planets have also been found
50:50but most of these are still larger than earth and still too close to their stars
50:55but the search for another earth is still in its infancy
51:05dr brice demery is a planet hunter and he may have found the promised land of planetary exploration
51:12a planet that could have warm mild weather weather just like a lovely summer evening in cambridge
51:19so we're looking for rocky planets they're similar to the earth in size
51:25but are located at the right distance from its star
51:28it's a bit like cooking a marshmallow
51:30if the marshmallow is too close to the fire then it will burn
51:33and if it is too far away it will never cook
51:35so we want the planet to be at the right distance that is just right
51:39for habitable conditions to happen
51:41we've just found three earth-sized planets that are beating a very cool star called trappist 1
51:49and those planets are remarkable the first one is located here and receive about four times the
51:55level of radiation than the earth does the second one located here receive twice the level of radiation
52:02than the earth does both planets are probably too hot to be habitable the third one is the most
52:09interesting one we're not exactly sure of its location right now but we believe it's located just
52:15here when it would receive about the same level of radiation as the earth does so this is our
52:22base candidate to date for habitability prospects could this planet really be another earth as ever
52:32this will depend on its atmosphere the atmosphere dramatically affects the habitability of a planet
52:39in the solar system venus the earth and mars are all within or very close the habitable zone but
52:46the atmosphere of venus and mars make them completely inhabitable
52:52even if this planet has the right type of atmosphere it could still be very different to earth
52:59these three planets are tidally locked to their star meaning that they show permanent day side
53:04that would be too hot for habitability and permanent night side that would be too cool while still
53:08having hospitable temperature between the two it's a bit like this marshmallow if i put it in the fire
53:15and i don't rotate it one side will be completely burnt while the other will be uncooked but in the
53:21middle it would be just right these planets could have a barren frozen wasteland on the night side
53:28a baking inferno on their day side and yet have a temperate and potentially habitable strip down
53:35the middle where it's permanent twilight but if you have a sick atmosphere surrounding this planet
53:46then all the heat coming from the star on the day side will recirculate to the night side making the
53:51day side cooler on the night side warmer to really know if any of these planets could be habitable we
54:00need to study their atmospheres but they're too small for even our best telescopes
54:12so the atmosphere in small planets actually are very thin so it's very difficult to detect them
54:18even with the state-of-the-art telescopes that we have today we've reached the limits of our current
54:25technology but nasa is building a new space telescope called the james webb which will enable us
54:33to study the atmospheres of exoplanets in far more detail than is possible today it'll have far greater
54:41light gathering abilities than its predecessor the hubble space telescope so james we have a mirror
54:48diameter of 6.5 meters which compared to the 2.4 meters of hubble means that james webb will collect
54:55seven times more photons than hubble does which means that we'll have more signal to study these planets
55:03the james webb will also be able to look at a far greater range of wavelengths so james webb will have
55:10the possibility to go much farther in the infrared that what a bell is able to do today
55:16which means that it will give us the ability to probe for many more compounds chemical compounds
55:21that what we are able to do with uh with hubble when james webb launches in 2018 astronomers are going
55:29to be able to study earth-sized planets and discover if they're potentially habitable
55:35i am convinced that we'll find an habitable planet maybe in the next five or maybe 10 years there's
55:43so many planets in our galaxy and this is the result from the past 20 years of a planet hunting
55:48that based on sheer probability we'll definitely find at least another habitable planet
55:57but for the time being our planet remains unique
56:00our exploration of other worlds so far suggests that it's a fairly rare combination of factors that
56:08make our climate and weather so hospitable what makes the earth so perfect for life is that first
56:14off it's rocky it's also got an atmosphere around it and our atmosphere is just right the size and the
56:22mass of our atmosphere is critical
56:23and in addition the composition of the atmosphere is just right the carbon dioxide and water in our
56:35atmosphere gives us just the right greenhouse effect it has too much greenhouse effect mars doesn't have
56:42enough we're also the right distance from our star we're just far enough away from the sun that we're
56:50not too hot but we're close enough that we're not too cold the temperature is perfect for water to exist
56:57in all three conditions and that is so vital for life to have developed and evolved on this planet
57:03and the earth even spins in the right way so the other thing that makes earth such a great place to
57:10live is that it spins on its axis every 24 hours so the day night temperatures never get super extreme
57:18so our planet has the right unique combination of things to make it just the right place for life
57:24to have developed and maintained itself for billions of years
57:32for thousands of years we've gazed up at the night sky wondering what other planets might be like
57:40astronomers began by studying our own solar system and now they're exploring the wider universe
57:47and can even study the weather on planets hundreds of light years away
57:53they've discovered climates and weather stranger than fiction alien worlds with extreme temperatures
58:01bizarre clouds and even ruby rain
58:04but they've yet to find another planet like earth with weather that's suitable for life that's not too
58:16hot or too cold so for the time being it looks like a warm and pleasant day on earth with a gentle breeze
58:24and a slight risk of rain might actually be the weirdest weather of them all
58:34a mecca for over 300 blue whales every year where the desert meets the sea explore the lesser known coast
58:41coast of the wild west next on bbc2
58:51you
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