Size Matters 2
Size Matters episode 2: This two-part special presented by Hannah Fry shows that when it comes to the universe, size really does matter. Hannah takes the audience into a thought experiment where the size of everything can be changed to reveal why things are the size they are.
Last Science posts on HDclump.com:
https://hdclump.com/rise-of-the-continents-episode-2-australia/
https://hdclump.com/rise-of-the-continents-episode-1-africa/
https://hdclump.com/eugenics-sciences-greatest-scandal-episode-1/
https://hdclump.com/the-story-of-science-episode-3-how-did-we-get-here/
https://hdclump.com/the-story-of-science-episode-2-what-is-the-world-made-of/
https://hdclump.com/the-story-of-science-episode-1-what-is-out-there/
https://hdclump.com/the-story-of-electricity-episode-3-revelations-and-revolutions/
https://hdclump.com/the-story-of-electricity-episode-2-the-age-of-invention/
https://hdclump.com/the-story-of-electricity-episode-1-spark/
https://hdclump.com/secrets-of-the-super-elements/
https://hdclump.com/the-artificial-intelligence-race/
Last Science posts on HDclump.com:
https://hdclump.com/rise-of-the-continents-episode-2-australia/
https://hdclump.com/rise-of-the-continents-episode-1-africa/
https://hdclump.com/eugenics-sciences-greatest-scandal-episode-1/
https://hdclump.com/the-story-of-science-episode-3-how-did-we-get-here/
https://hdclump.com/the-story-of-science-episode-2-what-is-the-world-made-of/
https://hdclump.com/the-story-of-science-episode-1-what-is-out-there/
https://hdclump.com/the-story-of-electricity-episode-3-revelations-and-revolutions/
https://hdclump.com/the-story-of-electricity-episode-2-the-age-of-invention/
https://hdclump.com/the-story-of-electricity-episode-1-spark/
https://hdclump.com/secrets-of-the-super-elements/
https://hdclump.com/the-artificial-intelligence-race/
Transcript
00:06Everything in the universe
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined6
undefined:undefined
undefined:undefinedor could things be different?
00:35What if things were smaller?
00:38What would be the harm in reducing
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined11
undefined:undefined
undefined:undefinedrelatively speaking, stronger.
00:53And it turns out smaller people
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined16
undefined:undefined
undefined:undefinedthings and people
01:11don't exist
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined20
undefined:undefined
undefined:undefinedthe size of something determines
01:27the very nature of the thing itself.
01:33You may never look at yourself,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined26
undefined:undefined27
undefined:undefined
undefined:undefineda parallel universe.
02:08One just like our own,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined32
undefined:undefined33
undefined:undefined
undefined:undefinedvery strange days indeed.
02:34In the last programme,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined38
undefined:undefined
undefined:undefinedalways, cataclysmically worse.
02:57So, in this programme,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined42
undefined:undefined
undefined:undefineda whole world of other challenges.
03:18As in the last episode,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined46
undefined:undefined
undefined:undefinedin our solar system.
03:35And it's also, of course,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined51
undefined:undefined
undefined:undefinedof rock and molten metal.
03:58And finally, at the core,
04:01a 2,400km-wide ball of solid
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined56
undefined:undefined
undefined:undefinedis exactly the size it is?
04:16What would happen
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined60
undefined:undefined
undefined:undefinedto find out.
04:31And there it is, a half-sized Earth.
04:34All made of the same stuff,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined66
undefined:undefined
undefined:undefinedwant to be messing with.
04:54For instance, gravity.
05:15As we discovered
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined71
undefined:undefinedsurface.
05:28Enough of a change to put
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined74
undefined:undefined
undefined:undefinedyou can jump higher...
05:52..and only fall at half the speed.
05:56Which would take a little bit of
undefined:undefined78
undefined:undefined79
undefined:undefined80
undefined:undefined81
undefined:undefined
undefined:undefinedothers, then the whole thing breaks.
06:26You see, gravity doesn't just
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined85
undefined:undefined
undefined:undefinedbe as thin as it used to be
06:42two-thirds of the way up Everest.
06:44There would be less oxygen
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined90
undefined:undefined
undefined:undefinedacclimatise to thinner air.
07:02After a few days,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined94
undefined:undefined
undefined:undefinedbeginning to look a lot like Norway.
07:19The spectacular phenomenon that is
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined98
undefined:undefined99
undefined:undefined
undefined:undefinedto the University of Maryland.
07:35Daniel Lathrop has spent 20 years
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined103
undefined:undefined
undefined:undefinedinsight into the workings of the
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined106
undefined:undefined
undefined:undefined
undefined:undefinedthe currents of molten metal
08:02generate a magnetic field.
08:05Dan built his model to study how
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined112
undefined:undefined
undefined:undefineduh, solar weather.
08:23So, the sun has storms
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined116
undefined:undefined
undefined:undefinedthat acts as a primary barrier
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined119
undefined:undefined
undefined:undefinedand giving us the beautiful,
08:50ethereal lights of the aurora.
08:53Of course, Dan never set out to
undefined:undefined123
undefined:undefined
undefined:undefinedhe's built several versions of
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined126
undefined:undefined
undefined:undefinedrapidly rotating.
09:17Next came
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined130
undefined:undefined
undefined:undefinedsphere and then a solid copper model
09:29of the inner core
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined
undefined:undefinedif the Earth were half size,
09:39we could then examine data between
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined137
undefined:undefined
undefined:undefinedbecause of its low melting point.
09:56But it still takes three days before
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined141
undefined:undefined
undefined:undefinedthat as the experiments
10:34have gotten larger, we have
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined145
undefined:undefined
undefined:undefinedDan's experiments reveal.
10:48When we go from larger
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined149
undefined:undefined
undefined:undefinedthere's kind of well-defined
11:00north-south magnetic poles,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined153
undefined:undefined
undefined:undefinedof the magnetic fields to change
11:14when you change its size.
11:17Half-sized Earth would likely
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined159
undefined:undefined
undefined:undefinedis that these multiple auroras
11:34are a sign that Earth's weaker
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined164
undefined:undefined
undefined:undefinedwith telecommunications.
11:55The sun still has these big, erm,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined168
undefined:undefined169
undefined:undefined
undefined:undefined
undefined:undefinedejections and it causes problems.
12:16And with every blast of solar wind,
12:19a weaker magnetic field
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined175
undefined:undefined
undefined:undefinedback to the Dark Ages.
12:37SHE LIGHTS MATCH
12:39Even on a normal-sized Earth,
12:41sometimes the radiation from solar
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined181
undefined:undefined
undefined:undefinedthat lasted 12 hours.
12:57The cause? Radiation from a solar
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined186
undefined:undefined
undefined:undefined
undefined:undefineddouble down on a problem
13:16that Joe was already
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined
undefined:undefinedwould supercharge that process.
13:30And, for Joe, that combination
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined194
undefined:undefinedin our atmosphere
13:44to escape off into space,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined197
undefined:undefined
undefined:undefined
undefined:undefinedgoing for a bit.
14:07But, over time, half-sized Earth
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined202
undefined:undefined203
undefined:undefined204
undefined:undefined
undefined:undefinedinto an uninhabitable desert.
14:30I think it's probably time
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined208
undefined:undefined60
undefined:undefined
undefined:undefineda little less ambitious,
15:15something that might work out
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined215
undefined:undefined
undefined:undefinedshapes and sizes.
15:33The largest, of course,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined219
undefined:undefined
undefined:undefinedis very small, two grams.
15:44It's essentially the size
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined223
undefined:undefined
undefined:undefinedwhich is the size of a rat.
15:56Humans are about 65 kilos,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined228
undefined:undefined
undefined:undefinedgood news.
16:18Aaron Clauset is a data scientist
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined233
undefined:undefined
undefined:undefinedfor this.
16:34Typically, species that are larger
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined
undefined:undefinedand as a result, they could
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined
undefined:undefinedto these kinds of events.
16:53So, in general, the larger
undefined:undefined241
undefined:undefined
undefined:undefinedgetting bigger and bigger,
17:03that might give us cause to worry.
17:05Does this mean then that we are
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined246
undefined:undefined
undefined:undefinedthat far off what it is today.
17:19But about 12,000 years ago,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined250
undefined:undefinedhad a lower nutritional value.
17:32And it's really only much more
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined254
undefined:undefined
undefined:undefinedwe don't have to worry
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined257
undefined:undefined
undefined:undefinedto be the other way around.
18:01Generally, smaller individuals
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined261
undefined:undefined262
undefined:undefined
undefined:undefinedspecies, and if we look at dogs,
18:18horses, elephants, it's actually
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined266
undefined:undefined267
undefined:undefined268
undefined:undefined
undefined:undefinedto size and what's down to, say,
18:39diet or exercise.
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined272
undefined:undefined
undefined:undefinedprofessional athletes.
18:55For example,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined276
undefined:undefined
undefined:undefinedand nicknames, but also, actually,
19:09it contains date of birth,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined281
undefined:undefined282
undefined:undefined283
undefined:undefined284
undefined:undefined
undefined:undefinedby looking at just a few.
19:41I took
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined288
undefined:undefined
undefined:undefinedmimics the original study,
19:57which made use of the full sample
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined
undefined:undefinedthat size DID matter.
20:10Being five centimetres shorter
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined297
undefined:undefinedwith a plausible explanation.
20:26In order to grow, our body makes
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined300
undefined:undefined
undefined:undefinedthat has been derived
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined303
undefined:undefined
undefined:undefinedknow, there's favourable conditions,
20:54that it would be wise to invest
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined307
undefined:undefined
undefined:undefinedin good shape.
21:07And actually, when conditions get
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined311
undefined:undefined
undefined:undefinedwe kind of stop growth,
21:21and we really invest the available
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined315
undefined:undefined316
undefined:undefined
undefined:undefinedof the tunnel.
21:39However, size is not the only thing
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined320
undefined:undefinedlots of exercise.
21:49So, it matters, but it's not
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined325
undefined:undefined326
undefined:undefined
undefined:undefinedfinding clothes to fit
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined329
undefined:undefined330
undefined:undefined331
undefined:undefined
undefined:undefined
undefined:undefineda sightseeing trip to London.
22:56Wherever she goes,
undefined:undefined335
undefined:undefined336
undefined:undefined
undefined:undefined
undefined:undefined
undefined:undefinedthat they all look at me.
23:22Did you have this one specially
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined343
undefined:undefined
undefined:undefinedKosen, the world's tallest man.
23:50Sultan's incredible stature
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined347
undefined:undefined
undefined:undefinedis a happier one.
24:08TRANSLATION: The doctors told me
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined351
undefined:undefined
undefined:undefinedis a practical one.
24:20The world is simply too big for her.
24:24TRANSLATION: One thing which
undefined:undefined355
undefined:undefined
undefined:undefinedfrom my family,
24:37like my sisters and brothers.
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined360
undefined:undefined
undefined:undefined
undefined:undefined
undefined:undefinedall my furniture.
25:08I don't have any problems
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined367
undefined:undefined
undefined:undefinedlive longer, and what's more,
25:29they reckon there'd be less
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined373
undefined:undefined
undefined:undefinedsmallest mammal.
25:47This is an Etruscan shrew.
25:50In the wild, they weigh just
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined378
undefined:undefined
undefined:undefinedstudied them for years.
26:03Ah, here they are.
26:05Cool. And I want to chase
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined384
undefined:undefined
undefined:undefinedwhat I'm going to do now.
26:24So we actually use this box here,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined388
undefined:undefined
undefined:undefinedout, it's a male.
26:46So, let me do this here.
26:49Female.
26:51OK. Now, let's figure out how much
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined394
undefined:undefined
undefined:undefinedmammalian equipment, it's all there,
27:07it's just very tiny.
27:09Like, uh, it's very difficult to
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined400
undefined:undefined
undefined:undefineda small body.
27:27So what we would see is they have a
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined404
undefined:undefined
undefined:undefinedvery nervous,
27:43one would see a breath per minute go
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined408
undefined:undefined
undefined:undefined
undefined:undefinedhard to fathom,
28:02but their hearts push
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined414
undefined:undefined
undefined:undefined
undefined:undefinedthese animals
28:23is that they are specialists for
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined419
undefined:undefined
undefined:undefinedenvironment is an important part
28:43of evolution, but filling this
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined424
undefined:undefined
undefined:undefined
undefined:undefinedproblem of their life.
29:04Uh, the immense heat loss they have,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined429
undefined:undefined
undefined:undefinedmeasured my skin,
29:19you would find that I have around a
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined433
undefined:undefined
undefined:undefinedlot more,
29:33around 20 times more for every gram.
29:36Now, this is all down to the
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined438
undefined:undefined
undefined:undefinedproportionally larger surface area
29:50is smaller animals lose
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined442
undefined:undefined443
undefined:undefined
undefined:undefined
undefined:undefinedfellows have problems keeping their
30:11body temperature up, try being
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined448
undefined:undefined
undefined:undefinedabsolutely incredible,
30:27and they look kind of unreal.
30:29I mean, their whole body is
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined454
undefined:undefined455
undefined:undefined
undefined:undefined
undefined:undefinedsame problems as the shrew,
30:59an insane heart rate and a
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined460
undefined:undefined
undefined:undefinedneed to be very good
31:19at replacing it.
31:20In fact, scientists have discovered
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined465
undefined:undefined466
undefined:undefined467
undefined:undefined
undefined:undefinedof course,
31:37with how big the animal is, so, an
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined471
undefined:undefined
undefined:undefined
undefined:undefined5,000kg,
31:56but how much does it eat?
31:59Just ask a zoo keeper.
32:05This is the amount of hay one of our
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined480
undefined:undefined
undefined:undefined
undefined:undefinedweight.
32:26In fact, if you map out the amount
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined486
undefined:undefined487
undefined:undefined
undefined:undefinedrelative to your size,
32:43increases rapidly.
32:45Or, to put that another way, the
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined493
undefined:undefined
undefined:undefinedspent looking for, and eating food.
33:10Just like the Etruscan shrew.
33:14But what if we went smaller still?
33:18So, if you were to take a
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined499
undefined:undefined
undefined:undefinedlose heat into the environment
33:29would be so great that it couldn't
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined503
undefined:undefined
undefined:undefinedits temperature.
33:44Going smaller means saying goodbye
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined507
undefined:undefined
undefined:undefinedthings start happening
33:55once you get down to the size
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined511
undefined:undefined512
undefined:undefined
undefined:undefineddifferent laws of physics.
34:17In terms of their relative strength,
34:19you might almost say that insects
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined517
undefined:undefined
undefined:undefineda small car,
34:28if you're a relatively big human.
34:29This is all because volume, area and
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined523
undefined:undefined524
undefined:undefined
undefined:undefined
undefined:undefinedits own weight,
34:55which would be the equivalent of me
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined529
undefined:undefined530
undefined:undefined
undefined:undefinedfriend, the square-cube law,
35:11which means that small creatures
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined534
undefined:undefined
undefined:undefineda countertop is equivalent
35:27to a normal-size human
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined538
undefined:undefined539
undefined:undefined
undefined:undefinedsize for an animal is,
35:49thought about a problem of why you
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined543
undefined:undefined
undefined:undefined
undefined:undefinedimportant for the ant,
36:02so the velocity with which the ant
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined548
undefined:undefined
undefined:undefinedmade of the same stuff.
36:16And there are even more advantages
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined552
undefined:undefined553
undefined:undefined
undefined:undefinedon a centrifuge,
36:30and start spinning it around.
36:33And we then try and measure at what
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined560
undefined:undefined561
undefined:undefined
undefined:undefinedsomehow the ants hang on.
36:55And during these measurements, we've
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined566
undefined:undefined
undefined:undefined
undefined:undefined
undefined:undefinedthat climbs with adhesive feet,
37:15they can't use a glue,
37:16because it will take a long time to
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined574
undefined:undefined
undefined:undefinedattract each other,
37:30then you have to convince them to
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined578
undefined:undefined
undefined:undefined
undefined:undefinedthey're tiny compared to gravity.
37:45But once more, being small
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined583
undefined:undefined
undefined:undefinedgood at climbing,
38:00but he might not understand why
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined587
undefined:undefined
undefined:undefineddifferent animals.
38:16So, whether you're a very small
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined591
undefined:undefined
undefined:undefinedmight present you with a problem
38:27regarding your cognitive abilities.
38:29The bottom line is, if you're
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined597
undefined:undefined
undefined:undefinedand a small fish.
38:47He'd be smart enough to spot food,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined601
undefined:undefined
undefined:undefinedsuddenly deadly.
39:04Surface tension is a force that
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined605
undefined:undefined
undefined:undefined
undefined:undefinednotice the droplet.
39:17So, great - tiny humans might be
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined610
undefined:undefined
undefined:undefinedthe wasps don't kill you,
39:29the coffee will?
39:31Because if that's what being a human
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined616
undefined:undefined
undefined:undefined
undefined:undefinedother sizes,
39:47because that's how evolution works.
39:49So, having established that, we
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined622
undefined:undefined
undefined:undefinedworld we live in.
40:12Lifespan, health, food,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined626
undefined:undefined
undefined:undefinedany more beautiful.
40:30But there's one thing we
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined630
undefined:undefined631
undefined:undefined632
undefined:undefined
undefined:undefinedstar known to astronomers
40:50as a yellow dwarf.
40:52But, of course, it's not really much
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined637
undefined:undefined638
undefined:undefined639
undefined:undefined
undefined:undefined
undefined:undefinedthe sun nonstop,
41:15apart from the whole being burned
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined644
undefined:undefined645
undefined:undefined646
undefined:undefined
undefined:undefined
undefined:undefinedwith the naked eye.
41:41Well, the key to this question is
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined652
undefined:undefined653
undefined:undefined
undefined:undefinedcentre begins to fuse together.
42:00This is, of course, nuclear fusion,
42:03which generates such enormous
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined658
undefined:undefined659
undefined:undefined
undefined:undefinedbest attempts...
42:20..JET - Joint European Torus. The
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined664
undefined:undefined
undefined:undefinedsuperheat gases until they fuse.
42:45The fusion takes place
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined668
undefined:undefined
undefined:undefinedthe density are at the maximum.
42:58The temperature there could be
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined672
undefined:undefined
undefined:undefined30 seconds at a time
43:10before it becomes unstable.
43:12Today they're running the fusion
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined678
undefined:undefined679
undefined:undefined
undefined:undefinedat the heart of a star.
43:48The challenge of making fusion
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined683
undefined:undefined
undefined:undefined
undefined:undefinedto trigger fusion,
44:05anywhere in the universe, inside of
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined688
undefined:undefined
undefined:undefinedthat this high-temperature ball
44:19of material wants to be pushed
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined692
undefined:undefined
undefined:undefined
undefined:undefinedthe pressure of the hot material.
44:33For stars, then, size
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined697
undefined:undefined
undefined:undefinedmassive, the temperature of the star
44:49in the centre will also go down,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined701
undefined:undefined
undefined:undefinedpacks enough punch?
45:06Well, before we get to that...
45:09Here's a quick bit of star
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined706
undefined:undefined
undefined:undefined
undefined:undefinedbrown dwarf,
45:24although still small by
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined711
undefined:undefined712
undefined:undefined
undefined:undefinednuclear fusion.
45:39So they're very faint and should
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined716
undefined:undefined
undefined:undefinedcurrent age of the universe
45:53to happen, they aren't
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined721
undefined:undefined
undefined:undefined
undefined:undefinedmake sense.
46:12Anyway, if we were changing the size
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined726
undefined:undefined
undefined:undefined
undefined:undefined
undefined:undefinedof Earth would Joe wake up to?
46:31Well, for starters, he'd be
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined732
undefined:undefined
undefined:undefineda much-reduced temperature.
46:47It would shift the peak wavelength
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined736
undefined:undefined
undefined:undefinedstars would have.
47:06The smallest stars, like this one,
47:09give off much less light, and
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined741
undefined:undefined
undefined:undefinedper square metre,
47:23which keeps Earth nice and toasty.
47:26But if we swapped our sun for a tiny
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined746
undefined:undefined747
undefined:undefined
undefined:undefined
undefined:undefinedthings were getting a bit nippy,
47:49to say the least.
47:55What would happen to a planet around
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined753
undefined:undefined
undefined:undefinedwould plummet...
48:13..because a star this size gives off
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined758
undefined:undefined
undefined:undefinedcomplete cold,
48:27deep, desperate freeze.
48:30All water on the planet
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined763
undefined:undefined764
undefined:undefined765
undefined:undefined766
undefined:undefined
undefined:undefinedsolve things?
48:53Earth's normal orbit is about 150
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined770
undefined:undefined771
undefined:undefined
undefined:undefinedzone would now be 100 times closer.
49:12So that's where we'd need to move
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined775
undefined:undefined
undefined:undefined
undefined:undefinedwould look much bigger in the sky,
49:35ten times bigger than he's used to.
49:38But other than that, would it
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined782
undefined:undefined
undefined:undefined
undefined:undefined
undefined:undefinedProxima Centauri,
49:57but it's actually our
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined788
undefined:undefined
undefined:undefinedsun, but it's up there
50:10if you know where to look.
50:12And at Queen Mary University
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined
undefined:undefinedthe sun's tiny neighbour.
50:24Proxima Centauri is the nearest
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined797
undefined:undefined
undefined:undefined
undefined:undefinedastonishing discovery
50:44by analysing the light that
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined802
undefined:undefined
undefined:undefinedgoes through the optical fibre
50:57to the basement of the observatory,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined807
undefined:undefined
undefined:undefined
undefined:undefinedspots in the middle of the traces.
51:14These are the footprints of
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined813
undefined:undefined
undefined:undefinedtwo months later
51:33and we take more data
51:35and we see that the
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined818
undefined:undefined
undefined:undefinedyears,
51:44then we see that it reaches a peak,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined823
undefined:undefined824
undefined:undefined
undefined:undefinedand forwards.
52:01It's the telltale sign of a
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined828
undefined:undefined
undefined:undefinedto our own.
52:15It is roughly Earth-sized, and
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined832
undefined:undefined
undefined:undefinedto its star.
52:31In fact, the maths shows that
undefined:undefined835
undefined:undefined
undefined:undefinedviable next step,
52:42as we branch out of our
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined839
undefined:undefined
undefined:undefinedevidence of life in planets
52:56like this one in Proxima Centauri
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined844
undefined:undefined
undefined:undefined
undefined:undefinedlight and the huge sun in the sky
53:16that would make things
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined850
undefined:undefined
undefined:undefinedwould be missing,
53:29and our green plants
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined854
undefined:undefined
undefined:undefinedeffect of orbiting
53:44so close to a star that literally
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined859
undefined:undefined
undefined:undefinedbe close to it,
53:59and the fact of being close to it
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined863
undefined:undefined
undefined:undefinedsynchronised to your width
54:12of the planet, so the same
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined867
undefined:undefined
undefined:undefinedeyeball planets.
54:30So, have we finally done a thought
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined871
undefined:undefined
undefined:undefinedtoo hot on the light side,
54:46too cold on the dark side.
54:49Oh, and I should mention that close
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined877
undefined:undefined
undefined:undefinedexpanding the sun,
55:08or making the planet bigger,
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined881
undefined:undefined
undefined:undefinedallowed us to exist
55:22in the first place.
55:25If our sun, or our planet had been a
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined886
undefined:undefined887
undefined:undefined
undefined:undefineddetermines our lifespan,
55:48because size determines how much
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined891
undefined:undefined
undefined:undefineddifferent problems.
56:01Evolution has produced completely
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined895
undefined:undefined
undefined:undefinedof the world around you
56:12and how you interact with it. The
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined899
undefined:undefined
undefined:undefinedvery successfully
56:24at all different sizes.
56:27I think size is important in
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined904
undefined:undefined
undefined:undefinedany more
56:38and the whole system will collapse.
56:39We set out to examine the nature of
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined909
undefined:undefined
undefined:undefinedit's not arbitrary.
56:54It's absolutely intrinsic to the
undefined:undefined00:00:10,000 --> 00:00:13,280
undefined:undefined913
undefined:undefined
undefined:undefined
undefined:undefined