- 1 day ago
Category
🎥
Short filmTranscript
00:00Space. It's fast, mysterious, and sometimes just plain weird.
00:10It keeps us up at night asking the big questions.
00:14Will I be on time?
00:19But what is time anyway?
00:24Where am I even going?
00:26Tonight, we're teaming up with two other curious minds, Hannah Fry and Dara O'Brien, to tackle the space mysteries that have you scratching your head.
00:38So, the main thing about Wolverine is, where do the blades go?
00:44Yeah, I know, and is he just not uncomfortable all the time?
00:46Hi!
00:47Hello, how are you?
00:48How are you doing?
00:49Nice to meet you.
00:50Hi.
00:51Hey, how are you?
00:52Thanks for having us.
00:54I think we're currently on your show, but then you're really on our show.
00:56I see.
00:57OK.
00:58Are we sure? There's more of us though, aren't there?
01:00It's all democracy.
01:03Buckle up for a cosmic chat about the weird, the wonderful, and the possibly extraterrestrial.
01:10Up to you, George.
01:19We had a long discussion earlier as to whether this was a sky at night meets curious cases, or curious cases meets the sky at night.
01:24There was some fisticuffs back today.
01:26Yeah.
01:27I think you won.
01:28Look at that.
01:29Welcome to the sky at nights.
01:31Get the air.
01:34Come here.
01:36MUSIC CONTINUES
02:06to a special edition of Curious Cases where we're going to do things a little bit differently tonight
02:10because Dara and I are currently in the BBC Radio Theatre at London's Broadcasting House
02:15and we have an audience.
02:18We are going to tackle quite a few of your questions on one single theme, space mysteries
02:30and to help us out we have called on some people who know their way around the universe
02:34the presenters from The Sky at Night.
02:42Yes, the longest winning science program in the world, older than Blue Peter, Coronet Street
02:46and Doctor Who's 68 years old, The Sky at Night is now.
02:49Wow, what an amazing guest for this evening. Welcome to all of you.
02:54Do you know how special The Sky at Night is, Dara?
02:55They had an asteroid named after them, after their show.
02:59What was it called, your asteroid?
03:00It's asteroid 57424 Calum Noctu, which is sort of Latin for The Sky at Night,
03:06but the number was the broadcast date of the first episode.
03:09And it looks like a dot. I've seen it in a telescope.
03:14Calum Noctu, that sounds very fancy, doesn't it?
03:16I looked up what Curious Cases would be if it was in Latin.
03:18What is it?
03:18It's Curiosa Casibus.
03:21I've got one named after me.
03:23Have you?
03:23Yeah, I do.
03:24Am I the only one?
03:26I'm not a full rank in the room.
03:28Yeah, it's asteroid 4901 and it's just called O'Brien, which is Latin for Dara O'Brien.
03:35What does yours look like through a telescope?
03:37Mine is a binary system.
03:39Oh, you're just showing.
03:41I mean, I was kind of forced into it, but it is very much my brag.
03:45It's a really interesting system.
03:47There's actually papers about mine.
03:48I mean, I've got a pretty good one.
03:51And also, it's not going to wipe out life on Earth.
03:53And that's kind of a, that's an upside.
03:55Yeah, that's also a flex.
03:57Yeah.
03:57Dara O'Brien's coming in, he's going to wipe out the Earth.
03:59He's not good.
04:00I don't think you'd get one really good week of publicity out.
04:03Off that's downhill.
04:04No, you know, honestly, I'd be on everything.
04:06You'd booked on everything.
04:07Graham Norton, finally return my calls.
04:11Okay, over the past few weeks,
04:12we've been asking you to send in your questions about space mysteries.
04:15And we're kicking off with Ariane in Ireland,
04:17who asked, what sound do stars make?
04:21Big shout out to the literalists who will go,
04:23oh, it's space.
04:24There's no sound in space.
04:25Like, whatever.
04:26George, why is this a brilliant question?
04:27It's totally a brilliant question,
04:28because stars make sounds.
04:30So, they have sound waves travelling through them,
04:33and we actually detect these sound waves on the surface of stars.
04:37And the field study of this is called astro seismology.
04:40So, yeah, it's really, really cool,
04:42because we can look at the waves as we detect them,
04:45and it tells us something about how big a star is,
04:48or what it's made of, or how dense it is.
04:51Unfortunately, though, because of the vacuum of space and all,
04:54those sound waves can't travel to us as sound waves.
04:57But, you know, we can detect them still by looking at the light.
04:59It makes the star wobble.
05:00It makes the starlight wobble.
05:02And do we ever turn those measurements
05:04into a sound wave we can hear?
05:06Yeah, absolutely.
05:07So, you just take any wave, and you say,
05:08this is what it would sound like if it was a sound wave
05:11of the same kind of shape and frequency.
05:13So, yeah, sonification of stars is definitely a thing.
05:15What's also really cool is that, like, they work,
05:17the stars work really similar to instruments.
05:20So, you know, like, small stars are like flutes,
05:22and big stars are like trombones.
05:24Like an orchestra.
05:25Yeah, exactly.
05:26You've brought in some space sounds to play for us,
05:29because you've picked different forms of intergalactic audio to play for us.
05:33Maggie, what did you bring in?
05:35Well, because I wanted to actually go for something
05:37that is actually a sound.
05:39Yeah.
05:39And the Cassini-Huygens space mission was a mission to Saturn.
05:43And Cassini went in orbit around Saturn, got some great data.
05:46But Huygens was a little probe made by the European Space Agency,
05:49and it actually landed on this moon, Titan.
05:52And as it actually fell through the atmosphere,
05:55because there was an atmosphere and there was a medium to carry the sound,
05:58we could actually listen to it.
06:00And I think this is a small section of the end as it actually sort of lands.
06:04I am, as always in these situations, wary of building it up too much.
06:08I know.
06:10I know.
06:11Let's take a moment.
06:12A symphony.
06:13I've not heard this, but I'm taking a wild guess at everyone's imagination
06:16is probably imagining something maybe more majestic than we're about to play.
06:21That's got to be right.
06:21Come on.
06:22It's okay.
06:23Yeah, okay.
06:24So this is the sound of the Huygens probe landing on Titan.
06:29Manage your expectations, everybody.
06:38That was very good.
06:39That was very good.
06:40Can we turn this into a competitive thing?
06:42Ooh.
06:44Giving that a 7 out of 10.
06:46All right, George, what sound did you choose?
06:50Can we hear mine first and then see if you can figure out what it is?
06:54Ooh.
06:54Oh, twist.
06:55Okay.
06:56Teased camp.
06:57All right.
06:58Okay, here it is.
06:59Was it a space elephant?
07:15No.
07:17Was it a buried choir?
07:20To me, that sounds like utter despair.
07:25Yeah.
07:26It's not an upbeat noise.
07:28Right?
07:28This is actually a sonification of a black hole at the center of a galaxy cluster.
07:34And so, like, if you can picture those really cool images that we have of black holes,
07:38and what they've done is kind of, like, swept around and, like, made the profile of the wave into a sound.
07:44So this is the sound of kind of sweeping around a black hole.
07:47And it just sounds like the despair at the end of the universe.
07:51Mm.
07:52I love it.
07:53Absolutely.
07:54Yay!
07:56Hey, you know what, George?
07:57Nothing says light entertainment, like, the impending death of falling into a black hole.
08:02So, you know, I'm going to give you an eight out of ten.
08:04I'm going to give you an eight out of ten.
08:07Damn, upbeat and chilly nipple.
08:09Oh, sorry.
08:10Yeah.
08:10You went for the kind of big smiler.
08:11It doesn't work.
08:12The sense of existential despair that we got from that was too good.
08:18Chris, what are you doing?
08:18Well, I have spent no expense, and I thought we'd go for the grandest and most important sound of all.
08:24So just after the Big Bang, when the universe was in a hot, dense state, there was enough matter around that you could have sound waves propagating through the universe.
08:33And we can still see the effects of this in something called the cosmic microwave background, which is the oldest light of all.
08:38So that means we know what sound waves were there, and we can work out what the spectrum is.
08:43And so that is the big sound.
08:44He's built it up.
08:45He's built it up.
08:46Go on, go on then.
08:47So this is the whole universe as an instrument.
08:50So the reason it sounds terrible is that you had all these frequencies at once.
09:02So the point is, the universe didn't just have one note playing.
09:07It was all of them, so you get this sort of white noise.
09:09But that was the whole universe.
09:11Well, ten for honesty.
09:13I think you oversold it.
09:15Do you know the bit on the M25 where it changes from a time I can't remember it?
09:20Yes.
09:21No, I think George wins on that round entirely.
09:23I think George wins.
09:24Do you agree, everybody?
09:26Yeah.
09:27There we go.
09:32Well, obviously, we are not going to do a show about space mysteries without talking about aliens.
09:37And this is a question in from Richard in Whitley Bay.
09:40Venus and Jupiter are deemed unseatable for life.
09:43But aren't there points in the upper atmospheres where the temperatures and pressures are similar to where life is found on Earth?
09:49Could airship drones be sent to look for exotic, simple forms of life?
09:54So there's two parts to this, obviously.
09:56George, what exactly are airship drones and why would we be sending them to Jupiter or Venus?
10:00So airship drones, think a balloon, but they're kind of robotic and you can operate them like drones remotely.
10:06Because there have been previously kind of balloons dropped through Venus's atmosphere
10:10and they want to do it again because they want to measure what's there.
10:12I think the issue, though, maybe with sending something like this to Jupiter is that it very rapidly, like, the pressure gets out of hand.
10:19So, you know, the whole thing would just...
10:21That's the technical term.
10:23It is the technical term.
10:25Yeah, and I think for Venus, like, you've also got to be careful.
10:27There's a lot of sulfur.
10:28It's a bit acidic.
10:29So, yeah, you've got to design your airship drone pretty carefully.
10:33I mean, you're basically trying to float a hot air balloon over a death planet.
10:37A little bit.
10:37Yeah, yeah, yeah.
10:38A little bit.
10:38Yeah, so, like, you know, think, like, weather balloons, but maybe more high-tech.
10:42There is an exciting history, though, of the series of Russian probes that attempted to land on Venus with almost hilarious misadventures.
10:50Yeah, they sent out one picture and then they melt.
10:52Yeah, the temperature and pressure, yeah, is so high.
10:55I think it was 23 minutes that it survived on the surface.
10:58So that one picture just melted away because it's horrendous.
11:02Okay, these exotic life forms that we're describing, I mean, what do you think?
11:06Do you think that there could be some genuinely on Venus or Jupiter or elsewhere?
11:10There is this layer in Venus's atmosphere which is about room temperature and pressure.
11:15It's still acidic, as you say, and that's, what's interesting is that's the layer that our mate Jane Greaves a few years ago announced that she'd found a chemical called phosphine in.
11:25And phosphine on Earth is made mostly, frankly, by penguins.
11:29It's a biosync, which is made by life, it's in penguin poo, amongst other things.
11:34And so the fact that we found it on Venus, maybe it's the product of some volcanism or some weird chemical process, but it could also be life hanging on in this region.
11:43Venus penguins!
11:44Venus penguins, very, very small Venus penguins.
11:47Venus penguins part, specifically.
11:50We always talk about life, but we put conditions of life as we know it.
11:54And I think that life could be so varied or so different from what we anticipate.
12:00Just to name drop, I did have this conversation with David Attenborough once.
12:03Sure.
12:04As you do.
12:05Well, you know, dames, I imagine we'll have dinner together every week.
12:08We all stick together.
12:10It was a number of years ago.
12:11And I was having a debate.
12:14I feel terrible because I was having an argument with our national treasure.
12:18And saying that I don't know if we actually need water for life.
12:21Life as we know it, yes.
12:23But maybe not, maybe life not as we know it.
12:26And so how do you define life?
12:28There might be a whole variety of life that we just don't anticipate.
12:32I don't want microbes, though.
12:33I want little green men.
12:36Luckily for Hannah, our friends at BBC Ideas have been looking at two approaches to finding them.
12:43Hello?
12:45Can you hear us?
12:46I can hear you.
12:46Can you hear me?
12:47Hello?
12:48Is there anybody out there?
12:50Well, that's the question, isn't it?
12:53Has been for as long as anyone can remember.
12:55Are we alone?
12:59It might sound like science fiction, but the universe is so vast.
13:04Many scientists think it's unrealistic to imagine we're the only form of life in it.
13:08The universe is full of natural radio waves generated by stars and planets and galaxies.
13:14But that emission is really very smooth.
13:16That's Mike Garrett, an astrophysicist and active member of SETI, the search for extraterrestrial intelligence.
13:23Artificial radio waves are very spiky because they convey information.
13:27So we're looking for anomalies, a signature of potentially other intelligent civilizations out there broadcasting to the universe.
13:36What SETI assumes is that the aliens are very motivated, that they're going out of their way to send us intentional signals for our benefit.
13:44And that's Douglas Backoach, the founder of METI, which stands for messaging extraterrestrial intelligence.
13:50They think listening is not enough.
13:53Maybe we should do the heavy lifting by reaching out first.
13:56Someone has to make the first move.
13:58Making the first move in any relationship has its risks.
14:02Opening oneself up to rejection.
14:04Or worse.
14:06Stories of alien fleets visiting Earth with the sole intention of wiping us out are common ground for science fiction.
14:12But there is a theory that if we're not careful, this could become science fact.
14:19I think one of the things that Stephen Hawking, famous cosmologist, was said about this idea of transmitting signals is that it might not turn out very well for us here on this planet.
14:30Just like it didn't turn out very well for the Native Americans when Columbus first settled there.
14:35But METI is amongst those who see this argument as a red herring.
14:40It's too late to hide.
14:41We're already known in the universe.
14:44Douglas and his colleagues believe that through TV and radio broadcasts, not to mention mobile phone towers, Earth has been leaking radiation into space for decades.
14:54This leakage is exactly what SETI look for as signs of life elsewhere.
14:59So it stands to reason that if aliens are listening, they could probably already hear us.
15:07Though not against communicating per se, Mike argues that we need to think much more carefully about what we want to say and how we want to say it.
15:17Who speaks for Earth and who has the right?
15:20When I see a lot of these signals being sent, they don't represent all over this planet.
15:25You know, just arbitrarily sending signals out into space is not very democratic.
15:31The first message sent into space for the benefit of aliens was in 1974, more than 50 years ago.
15:39It became known as the Arecibo message.
15:42And so far, we've received nothing in return, which returns us to Enrico Fermi's question.
15:48Where is everybody?
15:49There is a conundrum there, right, that when we turned on the opportunity to listen into space, it was strange that there wasn't a cacophony of sounds.
15:58Yes, I think the space age was a bit of a disappointment that we found that Mars just had craters, that Venus was this hellhole and so on.
16:05And I think people just expected it to be obvious that there was life in the cosmos.
16:11And it's not, but the universe is a big place.
16:14Actually, it's just a tiny sort of diversion.
16:17Last time I met David Attenborough, I was, no, no, because we were both doing the pre-Christmas selling books on radio interviews.
16:27And I had some kids book out of space, and I, when he sat down, we were chatting away from that, and I said, by the way, I should tell you, the book I've written, yeah, it has some stuff about animals in it.
16:37And Attenborough genuinely leaned in and went, you have planets, I have animals.
16:46That's great.
17:49So, here's what you can say.
17:51Oh, my.
17:53It's very brief.
17:54What's your name?
17:55What is the space?
17:56What's it made of?
17:57And how can we perceive it?
17:58Space must have an edge if its expanding right.
18:00Then how can it be infinite?
18:01Yeah.
18:02Okay.
18:04Marlon is already the boss level.
18:04All right, Maggie, give us, like, at least a rope barrier and a bounce.
18:08Yes, yes.
18:09The answer is, we don't know.
18:09There.
18:10I think because it's trying to understand sort of the concept of the universe.
18:14And so our current understanding of the universe is it began with something called the Big Bang.
18:20So it's sort of a singularity expanded out to create space and time.
18:25And so if you ask what is beyond space and time, it's a very hard concept to grapple.
18:30We don't know where its limits are.
18:32With things like the James Webb Space Telescope, we look at sort of light coming from the early universe.
18:37But we can't go beyond that because the light won't reach us, if you see what I mean.
18:42So yes, we are limited in what we know and what we can see.
18:45And we interpret that, but we believe it began and it's expanding outwards.
18:49Any guesses though, Chris?
18:50Well, we do have this edge to the observable universe.
18:52So as long as you're a practical astronomer, this question is easy to answer.
18:56Because the edge of the observable universe is the bit whose light is only just reaching us.
19:01So we can see the bit of the universe, which in the last 13.8 billion years has had time to send us light.
19:08And that's, you could put a line around that.
19:10If we froze the expansion of the universe, we can say what part of the universe that is.
19:14It's a guess, but the guess is that we live in this tiny fraction of the hole.
19:18So we've got this little bubble that we can see.
19:21That has an edge.
19:21But the whole thing, well, that could easily be infinite.
19:23The thing that's impossible to get your head around, I think intuitively, is the idea that our universe could have started in this Big Bang, this point in time, but it could have been infinite then and it could still be infinite now and it's expanding ever since.
19:36I don't have an intuitive answer to it.
19:39It's just the maths tells us that.
19:41Wow.
19:42Great question.
19:43Unsatisfying answer.
19:44Yes, I know.
19:45We have a lot of cosmological questions.
19:47A lot of questions about the shape of the universe.
19:50This one is from Stephen.
19:51When everything was created in the Big Bang, it all exploded outward and is still going.
19:57So why is the universe not shaped like a big donut with nothing in the middle?
20:02There's no central point, presumably.
20:04There's no one central point that we pushed away from.
20:06Because I think the idea of an explosion is a bit of a misunderstanding.
20:10You have been saying explosion for 80 years now.
20:14You've been going out of a...
20:15Big Bang.
20:16Rapid expansion, not explosion.
20:18Because explosion and fire is like...
20:20And it's sort of a matter starts here and then it's thrown outwards.
20:23But I think this is sort of the singularity, but it expands rapidly, but it expands outwards.
20:29So it isn't like an explosion where all the matter that was there is thrown outwards.
20:33But it's the matter itself is expanding outwards.
20:36And so I think getting...
20:37So then it's less likely to be sort of a donut, a toroid, it's more likely to be sort of a continuum, but sort of expanding outwards.
20:45But on the name, actually, the BBC is to blame for the name, the fact it's called the Big Bang.
20:50In this very building, Fred Hoyle in 1948, I think, Fred Hoyle was a Cambridge astronomer who didn't believe in the Big Bang Theory.
21:00And he gave a talk about modern cosmology on the radio and he wanted to disparage it.
21:04So he said, this Big Bang Theory.
21:07And the name stuck.
21:08So it was actually named by the theory's opponent.
21:11So it's his fault.
21:12But it's so memorable.
21:13So it stuck in the 90s.
21:15American Astronomy magazine got so fed up with this explosion problem that they had a competition for people to suggest other names for the Big Bang.
21:24Banny, but McBang.
21:25Yeah, yeah, yeah.
21:26That's what would happen now.
21:27But 10,000 people wrote in.
21:29And at the end, they had an expert panel judge them and they decided that Big Bang was the least worst name.
21:34And so Big Bang won with horrendous space kablooey was second, which still has the explosion problem.
21:41Yes.
21:41Yeah, so it's not an explosion.
21:43It's a stretching of space.
21:45And that's how you should think about it.
21:46Nonetheless, a donut is different to a sphere because its curvature is different.
21:49We can estimate the curvature of space.
21:52Is this donut shaped?
21:54Like there is a theory about this, right?
21:56Because, you know, so the four dimensional fabric of space time, people do actually research, you know, is it flat?
22:02Is it curved?
22:02And if it's curved, is it like a saddle?
22:04Is it open?
22:05Is it closed?
22:05And some people think that it might be shaped like a donut, a torus, which would be kind of like, you know, like going around like that.
22:11Which is pretty cool because then it means that like as you travel through the universe, eventually you'd come back on yourself.
22:16Like if you're inside a video game and it's like, you know, you can kind of go in a loop.
22:19But it's important to say that we know that if it's a donut, it's a very big donut.
22:23Very big.
22:24We can live only on a small part of the donut.
22:26So we're not ruling out the donut.
22:28We're not, but we see that the bit of the universe we can see is pretty flat.
22:31Yep.
22:32And so therefore, for it to be on a donut, we have to only have a tiny bit of the donut.
22:37The same way that if you stood on a football, you'd notice it was round.
22:40You stand on the earth, you have to do a bit more work.
22:42If you stand on something a billion times the size of the earth, it's very difficult to tell that you're on a sphere at all.
22:47And so we know that our universe appears to be flat.
22:50So you can have these exotic shapes, your donuts or your crumpets or whatever it is that you want the universe to be like, but we only see a tiny bit of it.
22:58Are we eliminating what you hinted at there that it would be enclosed?
23:03So I mean, like Chris says, we can't fully rule it out, but it's really unlikely.
23:06It looks pretty flat.
23:08So, you know, either the universe really is so much bigger than we can even imagine and everything that we can see for billions of light years is only a tiny bit or it's flat as a pancake.
23:19So we can go for pancake universe.
23:20I really like the idea that in maybe a hundred years' time, people will be sitting in this theatre and going, no, they call it a pancake universe because the BBC.
23:29It wasn't an insult, actually.
23:31Okay, so maybe a donut, maybe a pancake, definitely some sort of baked good.
23:35All right.
23:36That is almost all we have time for.
23:38Have we solved anything, have you think?
23:40No, no.
23:41That's astronomy.
23:43Do we ever really solve anything?
23:45No, but look, they've been going for 68 years.
23:46They need to go for another 68, so that's fine by me.
23:54While the cosmos remains mysterious, the skies never fail to inspire.
23:59So we can't finish up without Pete taking us through some of the upcoming sights.
24:04Since the clocks went back last month, darkness arrives an hour earlier and that gives us some great opportunities to enjoy the night sky.
24:15Early evening, we've still got the stars of summer, including the Summer Triangle, which includes the impressive constellation of Cygnus the Swan.
24:23Now, in the core of Cygnus the Swan, you've got an asterism called the Northern Cross.
24:28Later in the evening, you've got the stars of winter beginning to appear, and that also includes the magnificent constellation of Orion the Hunter, which is a great navigational aid.
24:38And from Orion, we can find other constellations, such as Gemini, the twins.
24:45To find Gemini from Orion, identify the two brightest stars in Orion, Rigel in the bottom right and Betelgeuse in the upper left.
24:57Extend the line they make, up and left for twice the distance, and you'll arrive at the pair of stars, which represents the heads of the twins, Castor and Pollux.
25:15Gemini is one of those unusual constellations that actually looks like what it's supposed to represent, well, with a bit of imagination at least.
25:24From the UK, it gets to its highest position in the sky between mid-November and mid-December in the early hours of the morning.
25:33Now, that puts it in a position which lifts it well above any turbulent atmosphere, which you'll find lower down, which makes it perfect for stargazing.
25:44Gemini is currently home to the gas giant Jupiter.
25:47It's easy to find, being the bright star-like object located just below Castor and Pollux.
25:54And there is a treat starting to come into view.
25:58Due to a Jovian equinox approaching in December 2026, Jupiter's moon Callisto will be seen appearing to cross Jupiter's disk for the next two years or so.
26:09A great time to watch is in the early hours of the 21st of November, when you'll be able to see the shadows of Io and Callisto crossing Jupiter's disk at the same time.
26:20Another treat coming at the end of the year is the Geminid meteor shower.
26:27As its name suggests, the shower's radiant is in Gemini, the radiant being the small area of sky that associated meteors appear to emanate from.
26:37The shower is active between the 8th and 16th of December, the peak occurring on the night of the 13th into the 14th of December.
26:46With the moon past last quarter and 12 hours of night sky darkness, it has the potential for a great show this year.
26:54The night sky is something which all of us can enjoy, so whether you're just looking up at beautiful stars above you or you're out in the early hours with a telescope and camera, I hope you get some great clear skies.
27:07As ever, there is an extended online star guide, which is available on our website, which is at www.bbc.co.uk forward slash sky at night.
27:21We love seeing any images you've taken.
27:24These are some of the highlights from what you've recently sent in via our Flickr account.
27:29Well, that's all for this year's series of the sky at night.
27:54We've had a fun packed trip across the cosmos covering everything from potentially hazardous asteroids,
27:59to the expanding universe, and all our episodes are still available on the BBC iPlayer.
28:05We'll be back with all the latest astronomical news in spring next year.
28:08But until then, happy stargazing and good night.
28:39Thanks, everyone.
28:41.
28:42.
28:48.
28:48.
Recommended
28:55
|
Up next
25:52
51:13
41:31
21:31
33:00
29:11
44:35
42:02
42:46
43:12
52:55
44:29
45:00
Be the first to comment