Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
0
00:00:00,010 --> 00:00:07,777
SUB BY : DENI AUROR@
https://aurorarental.blogspot.com/
1
00:00:01,923 --> 00:00:05,298
Across the universe, there are stellar systems
2
00:00:05,298 --> 00:00:07,631
completely unlike our own
3
00:00:07,631 --> 00:00:11,278
containing two stars instead of one.
4
00:00:11,278 --> 00:00:16,428
Our sun isn't so typical after all.
5
00:00:16,428 --> 00:00:20,534
Even the most fantastical imaginings of Sci-Fi writers,
6
00:00:20,534 --> 00:00:24,481
it doesn't even come close to what nature can produce.
7
00:00:24,481 --> 00:00:27,686
These are binary stars,
8
00:00:27,686 --> 00:00:30,189
and they create some of the deadliest
9
00:00:30,199 --> 00:00:33,164
places in the universe.
10
00:00:33,174 --> 00:00:36,409
Any planet that's close by is gonna get cooked.
11
00:00:38,813 --> 00:00:41,759
But some binaries may have an unexpected trick
12
00:00:41,759 --> 00:00:43,262
up their sleeve,
13
00:00:43,262 --> 00:00:48,080
one that transforms our search for alien worlds.
14
00:00:48,080 --> 00:00:50,644
When it comes to the occurrence of life on a planet,
15
00:00:50,654 --> 00:00:53,157
it may very well be that having two stars
16
00:00:53,157 --> 00:00:56,192
could be a lot better than having one.
17
00:00:54,997 --> 00:00:59,304
Imagine living in the light of two suns.
18
00:00:59,304 --> 00:01:00,937
Are we missing out?
19
00:01:00,937 --> 00:01:04,753
Could two stars be better than one?
20
00:01:07,759 --> 00:01:10,764
captions paid for by discovery communications
21
00:01:22,132 --> 00:01:23,805
Look at our sky.
22
00:01:23,805 --> 00:01:28,313
You see the same solitary sun rising
23
00:01:28,313 --> 00:01:31,088
and setting day after day.
24
00:01:34,534 --> 00:01:38,010
But throughout the galaxy, alien civilizations
25
00:01:38,010 --> 00:01:44,720
could be enjoying twin sunrises and twin sunsets
26
00:01:44,730 --> 00:01:50,940
because they orbit two stars instead of one.
27
00:01:50,940 --> 00:01:54,285
Half the star systems in our galaxy are binary stars.
28
00:01:54,285 --> 00:01:56,861
It appears to be a common root
29
00:01:56,861 --> 00:01:59,765
of stellar formation and evolution.
30
00:01:59,765 --> 00:02:02,871
So, we can't just focus on the single-star systems
31
00:02:02,871 --> 00:02:04,915
and think we have a complete picture.
32
00:02:06,947 --> 00:02:09,822
The complete picture may include planets
33
00:02:09,822 --> 00:02:13,437
orbiting binary stars...
34
00:02:13,437 --> 00:02:17,174
Alien worlds rooted in Sci-Fi fantasies
35
00:02:17,174 --> 00:02:21,722
that have inspired scientists for decades.
36
00:02:21,722 --> 00:02:24,266
If there is one single event that can most link
37
00:02:24,266 --> 00:02:25,898
to why I became a scientist,
38
00:02:25,898 --> 00:02:28,103
it was going to see the original "star wars" movie,
39
00:02:28,113 --> 00:02:30,917
"episode iv," when I was 7 years old.
40
00:02:30,917 --> 00:02:33,251
And I can remember that scene of Luke Skywalker
41
00:02:33,251 --> 00:02:35,554
standing out on the deserts of Tatooine,
42
00:02:35,564 --> 00:02:37,497
and there's a double sunset.
43
00:02:37,497 --> 00:02:40,603
The music swells up, and I can remember my 7-year-old heart
44
00:02:40,603 --> 00:02:42,545
kind of leaping out of my chest.
45
00:02:42,545 --> 00:02:44,418
That's the moment when I realized I wanted
46
00:02:44,418 --> 00:02:47,195
to be an astronomer.
47
00:02:47,195 --> 00:02:51,772
Could two stars be even better than one?
48
00:02:51,772 --> 00:02:54,005
Living on a planet that orbits a binary system
49
00:02:54,005 --> 00:02:55,548
could be really exciting.
50
00:02:55,548 --> 00:02:58,423
Imagine seeing two stars in the sky every day.
51
00:02:58,423 --> 00:02:59,654
That's pretty cool.
52
00:02:59,654 --> 00:03:00,826
But you know what?
53
00:03:00,826 --> 00:03:03,730
Sometimes it can get too exciting.
54
00:03:06,846 --> 00:03:08,949
Some binary systems
55
00:03:08,949 --> 00:03:11,825
are not places for Sci-Fi adventures.
56
00:03:11,825 --> 00:03:15,130
They're horror stories.
57
00:03:15,130 --> 00:03:17,434
In some cases, the interactions between
58
00:03:17,434 --> 00:03:18,676
binary stars get deadly.
59
00:03:18,676 --> 00:03:20,950
The stars can actually turn on each other.
60
00:03:20,950 --> 00:03:23,053
Binary stars are kind of like siblings.
61
00:03:23,053 --> 00:03:25,487
They're born together and they grow up together.
62
00:03:25,497 --> 00:03:29,533
But sometimes one of those siblings can be evil.
63
00:03:32,308 --> 00:03:36,756
This evil sibling is a pulsar.
64
00:03:36,756 --> 00:03:41,264
It starts life billions of years ago
65
00:03:41,264 --> 00:03:45,581
as the big brother in a binary.
66
00:03:45,581 --> 00:03:50,658
But something transforms it into a monster.
67
00:03:50,658 --> 00:03:52,862
When a large star dies, it will end its life
68
00:03:52,862 --> 00:03:56,107
as a supernova with a crazy big explosion.
69
00:03:56,107 --> 00:03:59,682
And a pulsar is what's left behind.
70
00:03:59,682 --> 00:04:01,718
This big brother's death triggers
71
00:04:01,728 --> 00:04:04,763
one of the biggest bangs in the universe.
72
00:04:10,512 --> 00:04:16,161
In the midst of the explosion, the star's core collapses,
73
00:04:16,161 --> 00:04:21,169
crushing material down into a hyper-dense ball.
74
00:04:21,169 --> 00:04:24,013
Rapid rotation and intense magnetic fields
75
00:04:24,013 --> 00:04:28,022
jump start twin beams of deadly radiation,
76
00:04:28,022 --> 00:04:30,324
and the pulsar comes to life.
77
00:04:32,339 --> 00:04:35,573
The pulsar has to be one of the most amazing monsters
78
00:04:35,583 --> 00:04:38,117
that the universe has ever thought of.
79
00:04:38,117 --> 00:04:40,391
They're only about 10 miles across,
80
00:04:40,391 --> 00:04:43,225
and yet they contain the mass of at least the sun
81
00:04:43,235 --> 00:04:45,369
or even sometimes twice the sun.
82
00:04:47,642 --> 00:04:49,245
The pulsar's sibling
83
00:04:49,245 --> 00:04:51,220
is lucky to live through the chaos
84
00:04:51,220 --> 00:04:54,525
of the nearby supernova.
85
00:04:54,525 --> 00:04:57,571
But it now orbits a brother from hell
86
00:04:57,571 --> 00:05:01,847
in a cosmic no-man's land.
87
00:05:01,847 --> 00:05:04,020
Orbiting a pulsar would be a pretty rough experience
88
00:05:04,020 --> 00:05:06,193
for any object in its vicinity.
89
00:05:06,193 --> 00:05:08,367
Pulsars are spitting out tremendous amounts
90
00:05:08,367 --> 00:05:10,671
of lethal radiation from their poles.
91
00:05:13,014 --> 00:05:16,019
It wouldn't be good to live on a planetary system
92
00:05:16,019 --> 00:05:18,625
near a pulsar because you are gonna be pointed
93
00:05:18,625 --> 00:05:23,334
toward a laser of planetary death.
94
00:05:23,344 --> 00:05:27,580
But these death rays can't last forever.
95
00:05:27,580 --> 00:05:29,322
Within a few million years,
96
00:05:29,322 --> 00:05:32,126
the pulsar spins itself to death.
97
00:05:34,099 --> 00:05:36,073
With its evil sibling dead,
98
00:05:36,073 --> 00:05:39,609
can the other star finally live in peace?
99
00:05:42,254 --> 00:05:47,002
Stars, as I tell students, are a lot like people.
100
00:05:47,002 --> 00:05:51,309
As they age, they tend to expand a bit.
101
00:05:51,309 --> 00:05:55,856
For a single star, it can expand and be as big as it likes.
102
00:05:55,856 --> 00:05:58,801
But in a binary, there's a problem.
103
00:05:58,801 --> 00:06:01,034
Now, this is where the story gets really interesting.
104
00:06:01,034 --> 00:06:03,178
See, you've got your companion star that's swelled up
105
00:06:03,178 --> 00:06:04,911
into a red giant.
106
00:06:04,911 --> 00:06:07,987
Some of that red giant material now can get incorporated
107
00:06:07,987 --> 00:06:09,429
back into the pulsar
108
00:06:09,429 --> 00:06:12,764
and spin it up into something called a millisecond pulsar.
109
00:06:15,339 --> 00:06:17,583
The bloated red giant
110
00:06:17,583 --> 00:06:20,216
can't hold on to its outer layers,
111
00:06:20,226 --> 00:06:24,262
and the pulsar begins to feed.
112
00:06:24,262 --> 00:06:26,206
Matter streams into it,
113
00:06:26,206 --> 00:06:28,480
transferring momentum into the pulsar,
114
00:06:28,480 --> 00:06:32,417
spinning it faster and faster
115
00:06:32,427 --> 00:06:36,493
until it rotates hundreds of times a second.
116
00:06:36,503 --> 00:06:38,668
The beams re-ignite.
117
00:06:38,668 --> 00:06:42,313
Our pulsar is back from the dead once more.
118
00:06:44,456 --> 00:06:47,491
They're dying and resurrecting over and over and over again.
119
00:06:47,491 --> 00:06:50,536
It's like a zombie you just can't kill.
120
00:06:52,640 --> 00:06:56,285
The red giant extends the life of its zombie brother
121
00:06:56,285 --> 00:06:58,290
billions of years longer.
122
00:07:02,136 --> 00:07:05,573
We know of hundreds of millisecond pulsars
123
00:07:05,583 --> 00:07:08,887
scattered throughout the cosmos.
124
00:07:08,887 --> 00:07:10,750
A terrifying thought.
125
00:07:14,796 --> 00:07:17,271
But it gets even scarier.
126
00:07:17,271 --> 00:07:19,644
Some of them are alone.
127
00:07:19,644 --> 00:07:21,818
What's happened to their sibling?
128
00:07:23,962 --> 00:07:26,126
Binary stars are ultimately responsible
129
00:07:26,136 --> 00:07:28,601
for the existence of millisecond pulsars.
130
00:07:28,601 --> 00:07:30,974
They only exist because they've sucked the life
131
00:07:30,974 --> 00:07:32,977
out of their companion stars.
132
00:07:35,762 --> 00:07:38,295
The millisecond pulsars that we see that are all alone
133
00:07:38,295 --> 00:07:40,298
may have just gotten rid of the body.
134
00:07:42,442 --> 00:07:47,582
This is PSR j1311-3430,
135
00:07:47,592 --> 00:07:51,899
a rare breed of millisecond pulsar known as a black widow.
136
00:07:55,044 --> 00:08:00,151
Like its spider namesake, it's deadly,
137
00:08:00,151 --> 00:08:02,926
one of the most massive fast-spinning pulsars
138
00:08:02,926 --> 00:08:06,030
in the universe,
139
00:08:06,040 --> 00:08:10,078
spitting out 100 times more radiation than a regular one.
140
00:08:11,851 --> 00:08:14,526
A black widow pulsar is right on the edge of physics.
141
00:08:14,526 --> 00:08:16,560
Any larger and it would be a black hole.
142
00:08:16,570 --> 00:08:19,434
The intense radiation is amazing.
143
00:08:19,444 --> 00:08:22,409
It's hard to fathom that these things exist.
144
00:08:22,419 --> 00:08:24,722
But generally, the rule is the following with the universe,
145
00:08:24,722 --> 00:08:26,225
which is big and old.
146
00:08:26,225 --> 00:08:30,030
If it can happen, it does happen.
147
00:08:30,030 --> 00:08:33,907
The black widow pulsar is the stuff of nightmares.
148
00:08:33,907 --> 00:08:36,651
Its radiation heats the companion star
149
00:08:36,651 --> 00:08:40,459
to over 21,000 degrees Fahrenheit,
150
00:08:40,459 --> 00:08:44,406
more than twice as hot as the surface of our sun.
151
00:08:49,253 --> 00:08:52,659
It is nothing less than stellar annihilation.
152
00:08:54,461 --> 00:08:58,538
Pulsars are already dramatic, energetic events.
153
00:08:58,538 --> 00:09:02,113
Now you're adding in, "hey, let's destroy a star."
154
00:09:02,113 --> 00:09:04,990
Black widow spiders famously eat their mates,
155
00:09:04,990 --> 00:09:08,134
and that's exactly what a black widow pulsar does.
156
00:09:08,134 --> 00:09:10,610
It actually uses the material from its companion star
157
00:09:10,610 --> 00:09:12,141
to spin itself up,
158
00:09:12,141 --> 00:09:14,715
and then it obliterates it completely.
159
00:09:14,715 --> 00:09:18,561
The companion star vanishes,
160
00:09:18,561 --> 00:09:23,370
murdered by its zombie sibling.
161
00:09:23,380 --> 00:09:25,442
It's the ultimate cosmic ingratitude.
162
00:09:25,442 --> 00:09:27,115
Here you have a companion star
163
00:09:27,115 --> 00:09:30,592
that's brought the pulsar back to life after it's died twice,
164
00:09:30,592 --> 00:09:33,467
and now its entire body is eviscerated
165
00:09:33,467 --> 00:09:35,170
by the radiation of the pulsar
166
00:09:35,170 --> 00:09:38,445
without a speck of dust to suggest it was ever there.
167
00:09:40,789 --> 00:09:42,460
These black widow pulsars
168
00:09:42,460 --> 00:09:45,095
are like the assassins of the galaxy.
169
00:09:45,095 --> 00:09:47,400
Not only do they destroy the star,
170
00:09:47,410 --> 00:09:51,045
they get rid of the evidence.
171
00:09:51,045 --> 00:09:53,090
When pulsars are involved,
172
00:09:53,090 --> 00:09:56,164
two stars are much worse than one.
173
00:09:59,741 --> 00:10:03,216
But could the opposite also be true?
174
00:10:03,216 --> 00:10:09,295
Can two stars create an oasis for habitable alien worlds?
175
00:10:28,100 --> 00:10:31,740
Binary stars offer an exciting possibility...
176
00:10:34,680 --> 00:10:38,980
Alien exoplanets orbiting two stars instead of one.
177
00:10:41,520 --> 00:10:44,690
These binary stars are everywhere,
178
00:10:44,690 --> 00:10:47,690
so the universe could actually be something like
179
00:10:47,690 --> 00:10:51,460
what we see in Sci-Fi movies.
180
00:10:51,460 --> 00:10:54,360
The Tatooine sky could be a real thing.
181
00:10:54,360 --> 00:10:57,500
There could be a planet with life and civilization,
182
00:10:57,500 --> 00:11:01,740
and in the sky, there could be two suns.
183
00:11:01,740 --> 00:11:06,470
What would it be like to live on these worlds?
184
00:11:06,480 --> 00:11:09,840
Could two stars be even better for life?
185
00:11:11,820 --> 00:11:15,180
Our home planet orbits a solitary sun
186
00:11:15,190 --> 00:11:19,850
in a safe region where life could evolve.
187
00:11:19,860 --> 00:11:22,220
Today we're familiar with a very stable,
188
00:11:22,230 --> 00:11:24,630
well-behaved star... Our own sun.
189
00:11:24,630 --> 00:11:26,460
And of course we know there's some solar weather.
190
00:11:26,460 --> 00:11:28,530
Sometimes it throws out high-energy particles
191
00:11:28,530 --> 00:11:30,570
that create the northern and Southern lights,
192
00:11:30,570 --> 00:11:32,900
but it's a very reliable star.
193
00:11:32,900 --> 00:11:34,970
It wasn't always that way.
194
00:11:34,970 --> 00:11:37,440
When the sun was much younger, it was more active,
195
00:11:37,440 --> 00:11:39,440
it was more violent.
196
00:11:43,310 --> 00:11:47,120
Our young sun rotated over 10 times faster
197
00:11:47,120 --> 00:11:49,320
than it does today,
198
00:11:49,320 --> 00:11:52,550
causing its magnetic field to twist and tangle,
199
00:11:52,560 --> 00:11:55,620
sending out huge solar flares.
200
00:11:58,330 --> 00:11:59,830
Solar flares can be very bad for
201
00:11:59,830 --> 00:12:01,060
the habitability of a planet,
202
00:12:01,060 --> 00:12:03,130
particularly if you're very close to the star,
203
00:12:03,130 --> 00:12:04,770
and the reason's because solar flares
204
00:12:04,770 --> 00:12:06,930
essentially represent high-energy radiation.
205
00:12:06,940 --> 00:12:08,840
For example, high-energy protons.
206
00:12:08,840 --> 00:12:11,040
They smash into the atmosphere and they can strip away
207
00:12:11,040 --> 00:12:14,610
gas off the atmosphere.
208
00:12:14,610 --> 00:12:18,650
Picture the early solar system...
209
00:12:18,650 --> 00:12:20,620
Flares and solar storms
210
00:12:20,620 --> 00:12:24,950
attack the atmospheres of rocky planets.
211
00:12:24,950 --> 00:12:30,020
Deadly charged particles can rip them away molecule by molecule.
212
00:12:32,500 --> 00:12:36,700
Without an atmosphere, liquid water cannot survive,
213
00:12:36,700 --> 00:12:40,270
and no liquid water means no life.
214
00:12:42,610 --> 00:12:46,570
In the very early stages, our solar system was an awful place.
215
00:12:46,580 --> 00:12:49,440
The sun was young and highly irregular
216
00:12:49,450 --> 00:12:53,750
and emitting lots of energy in our region.
217
00:12:53,750 --> 00:12:56,780
It took a long time, probably 500 million years or so
218
00:12:56,790 --> 00:12:58,390
before the solar system
219
00:12:58,390 --> 00:13:01,160
calmed down enough to imagine
220
00:13:01,160 --> 00:13:06,330
that anything like life could evolve here on earth.
221
00:13:06,330 --> 00:13:08,500
This is a galaxy-wide problem
222
00:13:08,500 --> 00:13:10,970
for planets orbiting one star.
223
00:13:13,000 --> 00:13:17,310
Take Proxima Centauri, the closest star to our sun.
224
00:13:17,310 --> 00:13:19,010
It's a red dwarf,
225
00:13:19,010 --> 00:13:22,240
the most common type of star in the milky way.
226
00:13:24,650 --> 00:13:30,790
And it even has its own planet named Proxima B.
227
00:13:30,790 --> 00:13:35,160
But Proxima Centauri has not treated its planet gently.
228
00:13:37,630 --> 00:13:40,660
If Proxima B has any liquid water,
229
00:13:40,660 --> 00:13:43,300
it would have to be extremely lucky.
230
00:13:46,200 --> 00:13:48,140
Proxima Centauri would have caused
231
00:13:48,140 --> 00:13:49,870
huge amounts of energy to come out,
232
00:13:49,870 --> 00:13:51,570
and it would effectively strip away
233
00:13:51,570 --> 00:13:55,540
Proxima B of any kind of atmosphere or surface water,
234
00:13:55,550 --> 00:13:59,480
thereby removing any chance of there being habitable world.
235
00:13:59,480 --> 00:14:01,520
The only hope we have left for Proxima B
236
00:14:01,520 --> 00:14:03,920
is a strong magnetic field.
237
00:14:03,920 --> 00:14:06,590
This would surround and protect the planet
238
00:14:06,590 --> 00:14:09,390
from the onslaught of violent energy
239
00:14:09,390 --> 00:14:11,090
that comes out of Proxima Centauri,
240
00:14:11,090 --> 00:14:13,030
and that way, there could still be an ocean,
241
00:14:13,030 --> 00:14:15,100
there could be an oxygen-rich atmosphere,
242
00:14:15,100 --> 00:14:17,000
and perhaps habitable environment,
243
00:14:17,000 --> 00:14:19,200
somewhere where life could have started.
244
00:14:19,200 --> 00:14:22,340
But right now for Proxima B, odds are stacked against it.
245
00:14:27,780 --> 00:14:29,610
Earth's strong magnetic field
246
00:14:29,610 --> 00:14:32,850
protects us from the sun's worst outbursts,
247
00:14:32,850 --> 00:14:35,220
allowing liquid water to survive.
248
00:14:37,950 --> 00:14:40,350
But other planets, like Mars and Mercury,
249
00:14:40,360 --> 00:14:42,960
have not been so lucky.
250
00:14:42,960 --> 00:14:46,490
Solar storms blasted their young atmospheres...
251
00:14:48,770 --> 00:14:51,930
Until they became thin and weak,
252
00:14:51,940 --> 00:14:54,770
snuffing out any chances for life.
253
00:14:59,810 --> 00:15:04,180
But could binary systems actually make things easier,
254
00:15:04,180 --> 00:15:10,350
where planets orbit around two stars instead of one?
255
00:15:10,350 --> 00:15:13,790
Young stars can be very violent and chaotic,
256
00:15:13,790 --> 00:15:16,020
but in the system where there are two stars,
257
00:15:16,030 --> 00:15:19,760
the interaction of those stars can slow down their rotation,
258
00:15:19,760 --> 00:15:23,030
and that means that that violence can be slowed down.
259
00:15:23,030 --> 00:15:25,400
These solar storms can be tempered
260
00:15:25,400 --> 00:15:28,070
so they're not as violent, they're not as frequent,
261
00:15:28,070 --> 00:15:32,270
and if any young planet is formed with an atmosphere,
262
00:15:32,280 --> 00:15:34,280
it can keep it.
263
00:15:34,280 --> 00:15:37,610
So, when it comes to the occurrence of life on a planet,
264
00:15:37,610 --> 00:15:40,110
it may very well be that having two stars
265
00:15:40,120 --> 00:15:43,650
could be a lot better than having one.
266
00:15:43,650 --> 00:15:46,250
Gravitational interactions
267
00:15:46,260 --> 00:15:49,690
can slow down the spin of two close sun-like stars,
268
00:15:49,690 --> 00:15:54,460
giving life the chance to develop.
269
00:15:54,460 --> 00:15:57,130
But not just on one world...
270
00:15:57,130 --> 00:16:02,070
On many planets throughout the system.
271
00:16:02,070 --> 00:16:04,040
With two stars in the middle of a solar system,
272
00:16:04,040 --> 00:16:05,510
you have twice the amount of heat,
273
00:16:05,510 --> 00:16:06,910
twice the amount of light,
274
00:16:06,910 --> 00:16:08,510
and that extends the habitable zone
275
00:16:08,510 --> 00:16:10,610
farther out into the solar system.
276
00:16:13,750 --> 00:16:16,580
For planetary scientist Jani Radebaugh,
277
00:16:16,590 --> 00:16:20,720
exploring systems like this would be a dream come true.
278
00:16:24,190 --> 00:16:27,460
To me, it is so thrilling that worlds like this could exist
279
00:16:27,460 --> 00:16:29,800
and that they might even harbor life.
280
00:16:29,800 --> 00:16:32,500
I mean, there could be a Sci-Fi desert planet like this one
281
00:16:32,500 --> 00:16:36,740
with twin suns, my personal favorite and one
282
00:16:36,740 --> 00:16:38,810
that I can't wait to visit, or if we wanted,
283
00:16:38,810 --> 00:16:41,680
we could just hop over to another habitable planet
284
00:16:41,680 --> 00:16:43,810
and find something completely different.
285
00:16:46,920 --> 00:16:48,750
Galactic backpackers could explore
286
00:16:48,750 --> 00:16:51,490
a variety of Sci-Fi landscapes.
287
00:16:55,330 --> 00:16:59,460
Perhaps alien civilizations are already out there,
288
00:16:59,460 --> 00:17:02,700
living on these habitable worlds.
289
00:17:06,440 --> 00:17:10,910
Two suns could create better star systems than one,
290
00:17:10,910 --> 00:17:13,940
but they could also make things chaotic,
291
00:17:13,940 --> 00:17:18,850
shooting entire worlds into space at hyper speed.
292
00:17:37,460 --> 00:17:40,230
what would life be like
293
00:17:40,230 --> 00:17:42,630
on a planet in a binary system?
294
00:17:42,630 --> 00:17:45,740
Could it be better?
295
00:17:45,740 --> 00:17:51,410
Or is planet earth really as good as it gets?
296
00:17:51,410 --> 00:17:53,740
If you're looking for an abode for life in the galaxy,
297
00:17:53,750 --> 00:17:56,510
we tend to, you know, look for a rather cozy existence out there,
298
00:17:56,510 --> 00:17:58,650
but, you know, it's possible that stars can take you
299
00:17:58,650 --> 00:18:00,380
on a bit of a wild ride sometimes.
300
00:18:03,550 --> 00:18:04,950
Over the past decade,
301
00:18:04,960 --> 00:18:07,390
we've observed mysterious objects
302
00:18:07,390 --> 00:18:10,030
hurtling through the galaxy.
303
00:18:10,030 --> 00:18:13,730
Scientists call them hypervelocity stars.
304
00:18:16,570 --> 00:18:18,870
When we say hypervelocity stars,
305
00:18:18,870 --> 00:18:21,600
we're talking some hyper velocities.
306
00:18:21,610 --> 00:18:25,570
They've been observed moving up to 620 miles per second.
307
00:18:25,580 --> 00:18:28,610
You're talking about something the size of a star, the sun,
308
00:18:28,610 --> 00:18:31,810
an octillion tons of mass or something like that
309
00:18:31,820 --> 00:18:36,090
getting flung away way faster than a rifle bullet.
310
00:18:38,020 --> 00:18:40,290
These hypervelocity stars
311
00:18:40,290 --> 00:18:42,790
start off in a binary system,
312
00:18:42,790 --> 00:18:47,360
but something tears them apart... Something big.
313
00:18:49,470 --> 00:18:51,670
In order to create a hypervelocity star,
314
00:18:51,670 --> 00:18:55,140
you need a very intense source of gravitational power.
315
00:18:55,140 --> 00:18:57,040
Well, the most intense source we know of
316
00:18:57,040 --> 00:18:59,310
is the black hole at the center of the galaxy.
317
00:19:06,520 --> 00:19:09,990
This black hole is Sagittarius a-star.
318
00:19:14,490 --> 00:19:16,660
It is supermassive...
319
00:19:16,660 --> 00:19:21,530
Four million times the mass of our sun.
320
00:19:21,530 --> 00:19:24,570
Two stars stray a little too close,
321
00:19:24,570 --> 00:19:28,100
and the enormous gravity of the black hole pulls at them.
322
00:19:30,070 --> 00:19:34,080
But the star closest feels a much stronger tug,
323
00:19:34,080 --> 00:19:37,380
and this binary system gets ripped apart.
324
00:19:40,590 --> 00:19:43,020
It's a little bit like the Olympic hammer throw,
325
00:19:43,020 --> 00:19:46,420
where the hammer is one star in the binary system
326
00:19:46,420 --> 00:19:49,490
and the Olympian is the other star,
327
00:19:49,490 --> 00:19:50,760
with the cord connecting the hammer
328
00:19:50,760 --> 00:19:52,030
being the gravitational tie
329
00:19:52,030 --> 00:19:53,800
between the binary stars.
330
00:19:53,800 --> 00:19:56,530
If you cut that cord, the other star can go flying off
331
00:19:56,530 --> 00:19:59,070
at very, very high speed.
332
00:20:01,070 --> 00:20:02,740
Once the cord is cut,
333
00:20:02,740 --> 00:20:05,110
the binary stars separate forever.
334
00:20:07,450 --> 00:20:09,780
One is trapped in the gravitational grip
335
00:20:09,780 --> 00:20:13,180
of the black hole.
336
00:20:13,180 --> 00:20:16,120
The other is flung out of the galaxy,
337
00:20:16,120 --> 00:20:20,720
becoming a literal shooting star.
338
00:20:20,730 --> 00:20:25,790
But the star may not be alone.
339
00:20:25,800 --> 00:20:29,230
If a planet is gravitationally bound to a star
340
00:20:29,230 --> 00:20:32,670
and that star gets ejected from the system,
341
00:20:32,670 --> 00:20:34,500
if conditions are right,
342
00:20:34,510 --> 00:20:37,640
that planet can hitch a ride with that star.
343
00:20:37,640 --> 00:20:40,310
Where the star goes, the planet goes.
344
00:20:45,050 --> 00:20:47,580
If you're on planet around a hypervelocity star,
345
00:20:47,590 --> 00:20:50,490
you would be the envy of poets and scientists everywhere
346
00:20:50,490 --> 00:20:54,290
because you would have the most breathtaking view imaginable.
347
00:20:54,290 --> 00:20:56,430
You would start at the very center of the galaxy,
348
00:20:56,430 --> 00:20:59,860
you'll have this beautiful view of the supermassive black hole.
349
00:21:03,430 --> 00:21:05,970
Generation after generation
350
00:21:05,970 --> 00:21:07,800
on this hypervelocity planet
351
00:21:07,810 --> 00:21:11,540
would be treated to thrilling new views of the galaxy.
352
00:21:15,680 --> 00:21:17,580
By the time you're done as you're ejected,
353
00:21:17,580 --> 00:21:21,050
you would see the entire milky way galaxy,
354
00:21:21,050 --> 00:21:25,090
everything, and it would recede away from you
355
00:21:25,090 --> 00:21:29,060
as you moved off into space to who knows where.
356
00:21:33,360 --> 00:21:36,630
Hypervelocity planets just go to show
357
00:21:36,630 --> 00:21:40,940
that the universe is way stranger than fiction.
358
00:21:40,940 --> 00:21:44,070
As we learn more about stars and stellar systems,
359
00:21:44,080 --> 00:21:48,280
even the most fantastical imaginings of Sci-Fi writers,
360
00:21:48,280 --> 00:21:51,310
it doesn't even come close to what nature can produce.
361
00:21:54,720 --> 00:21:57,720
This hypervelocity star and planet
362
00:21:57,720 --> 00:22:00,120
go on the journey of a lifetime,
363
00:22:00,120 --> 00:22:02,860
but what about the stranded companion star,
364
00:22:02,860 --> 00:22:05,190
stuck in the center of the galaxy
365
00:22:05,200 --> 00:22:09,470
next to a supermassive black hole?
366
00:22:09,470 --> 00:22:13,500
It, too, could have a planet orbiting it,
367
00:22:13,500 --> 00:22:16,410
but it's a world living on borrowed time.
368
00:22:18,810 --> 00:22:22,140
If there's a planet orbiting the star that gets left behind
369
00:22:22,150 --> 00:22:23,950
by the hypervelocity star,
370
00:22:23,950 --> 00:22:25,350
so the planet is now orbiting
371
00:22:25,350 --> 00:22:27,650
the star that's orbiting the black hole,
372
00:22:27,650 --> 00:22:30,790
that's not probably gonna last very long.
373
00:22:30,790 --> 00:22:34,460
Typically, the little guy... Pew! Gets shot away.
374
00:22:37,960 --> 00:22:40,730
So it's entirely possible that we have hypervelocity
375
00:22:40,730 --> 00:22:44,630
rogue planets, planets without a star
376
00:22:44,640 --> 00:22:46,000
that are shooting out of the galaxy
377
00:22:46,000 --> 00:22:49,640
at high speed, as well.
378
00:22:49,640 --> 00:22:52,240
But it's not a trip you'd want to take.
379
00:22:56,780 --> 00:22:59,350
Because this world is destined to wander
380
00:22:59,350 --> 00:23:02,820
the emptiness of space forever and alone.
381
00:23:04,790 --> 00:23:05,920
The problem with the planet
382
00:23:05,920 --> 00:23:08,290
is that it's no longer bound to a star,
383
00:23:08,290 --> 00:23:11,560
so the outer surface would most likely freeze.
384
00:23:13,660 --> 00:23:14,930
Binary stars
385
00:23:14,930 --> 00:23:19,130
can create weird environments for planets.
386
00:23:19,140 --> 00:23:23,770
You could get an exhilarating view of the galaxy,
387
00:23:23,770 --> 00:23:26,780
or freeze on an icy wasteland.
388
00:23:35,120 --> 00:23:39,390
But astronomers are finding bizarre new systems
389
00:23:39,390 --> 00:23:42,730
where stars are not being torn apart,
390
00:23:42,730 --> 00:23:47,000
they're being driven together,
391
00:23:47,000 --> 00:23:52,330
creating a cosmic event coming soon to our galaxy.
392
00:24:09,450 --> 00:24:12,180
are two stars better than one?
393
00:24:14,550 --> 00:24:19,020
Binary systems are certainly very dramatic.
394
00:24:19,020 --> 00:24:22,590
There's even one that has two stars so close,
395
00:24:22,590 --> 00:24:26,160
they're touching.
396
00:24:26,160 --> 00:24:31,370
KIC 9832227 is a very interesting binary system.
397
00:24:31,370 --> 00:24:33,700
It's what we call a contact binary.
398
00:24:33,710 --> 00:24:37,570
So this means that the two stars are basically in contact,
399
00:24:37,580 --> 00:24:39,080
but they're separate stars.
400
00:24:39,080 --> 00:24:43,010
They share a common atmosphere or envelope.
401
00:24:43,010 --> 00:24:44,850
One's about a third the mass of the sun,
402
00:24:44,850 --> 00:24:47,450
one about 1.4 times the mass of the sun,
403
00:24:47,450 --> 00:24:51,820
and they're rotating around each other every 11 hours.
404
00:24:51,820 --> 00:24:55,530
2017... Scientists from Calvin college
405
00:24:55,530 --> 00:24:59,330
reveal an exciting discovery.
406
00:24:59,330 --> 00:25:04,900
These binary stars are moving even closer together.
407
00:25:04,900 --> 00:25:08,300
They do the math and make a bold prediction.
408
00:25:10,880 --> 00:25:14,340
So, this star is different from all other contact binary stars
409
00:25:14,350 --> 00:25:17,050
we've studied because this one, we believe,
410
00:25:17,050 --> 00:25:20,150
in the next five years is going to merge,
411
00:25:20,150 --> 00:25:23,090
spiral in together, and explode.
412
00:25:25,920 --> 00:25:28,520
But it's a star close enough to us...
413
00:25:28,530 --> 00:25:30,930
Only 1,800 light years away...
414
00:25:30,930 --> 00:25:33,060
That when it explodes, it'd be bright enough
415
00:25:33,060 --> 00:25:35,330
to see with your naked eye.
416
00:25:35,330 --> 00:25:38,270
Two stars crashing together...
417
00:25:38,270 --> 00:25:42,410
An event known as a red Nova.
418
00:25:42,410 --> 00:25:44,140
If this is true, if you really see it,
419
00:25:44,140 --> 00:25:45,640
it would be fabulous,
420
00:25:45,640 --> 00:25:47,510
because not only would it validate
421
00:25:47,510 --> 00:25:49,110
this amazing prediction,
422
00:25:49,110 --> 00:25:51,650
but we have something new to look at in the night sky.
423
00:25:51,650 --> 00:25:55,220
If this comes through, this would just be
424
00:25:55,220 --> 00:25:57,450
the event of my lifetime.
425
00:26:00,130 --> 00:26:03,630
We don't get to predict too many things in astronomy
426
00:26:03,630 --> 00:26:04,860
except, you know,
427
00:26:04,860 --> 00:26:07,300
"a billion years from now, this thing will happen."
428
00:26:07,300 --> 00:26:11,370
So you have to appreciate what this thing is.
429
00:26:11,370 --> 00:26:15,070
These stars are probably billions of years old.
430
00:26:15,070 --> 00:26:18,680
We're just so lucky to be able to see this right at the end
431
00:26:18,680 --> 00:26:20,840
where we just have a few years left...
432
00:26:20,850 --> 00:26:24,280
A few years out of a billion-year life span.
433
00:26:28,090 --> 00:26:31,320
It's an amazing cosmic coincidence
434
00:26:31,320 --> 00:26:34,960
brought to you by the number three.
435
00:26:34,960 --> 00:26:38,230
Before these stars came into close contact,
436
00:26:38,230 --> 00:26:40,460
they may have had a neighbor...
437
00:26:40,470 --> 00:26:46,300
A distant third star that set this all in motion.
438
00:26:46,300 --> 00:26:47,740
Whenever you have three objects,
439
00:26:47,740 --> 00:26:51,170
the gravitational dynamics becomes incredibly complicated.
440
00:26:52,840 --> 00:26:55,680
The third star pulls on the binary
441
00:26:55,680 --> 00:26:57,480
as the two orbit each other,
442
00:26:57,480 --> 00:27:01,920
stretching them out basically into an elongated orbit.
443
00:27:01,920 --> 00:27:03,720
The two stars resist that,
444
00:27:03,720 --> 00:27:06,720
trying to circularize their orbit again.
445
00:27:06,730 --> 00:27:09,390
That back and forth interaction
446
00:27:09,390 --> 00:27:11,760
pushes the third star further away,
447
00:27:11,760 --> 00:27:15,430
pulls the two stars closer.
448
00:27:15,430 --> 00:27:18,330
The stars have been shoved together,
449
00:27:18,340 --> 00:27:21,870
but their story is about to get even weirder.
450
00:27:24,940 --> 00:27:27,540
Matter will stream off the smaller star
451
00:27:27,550 --> 00:27:31,710
until it is too gravitationally weak to hold its position...
452
00:27:33,890 --> 00:27:36,950
Driving their orbits even tighter together,
453
00:27:36,960 --> 00:27:39,620
moving them faster and faster.
454
00:27:41,790 --> 00:27:46,630
Finally, the smaller star will plunge into the larger one,
455
00:27:46,630 --> 00:27:50,400
tearing through it...
456
00:27:50,400 --> 00:27:53,970
And blasting hundreds of trillions of tons of debris
457
00:27:53,970 --> 00:27:56,840
in every direction.
458
00:27:56,840 --> 00:27:59,110
This would be an enormous amount of energy.
459
00:27:59,110 --> 00:28:01,340
Explosion at its peak will be 10,000 times
460
00:28:01,350 --> 00:28:05,480
brighter than the star is today.
461
00:28:05,480 --> 00:28:10,190
This collision will also be an act of creation.
462
00:28:10,190 --> 00:28:15,990
The cores of the two stars will collide and become one,
463
00:28:15,990 --> 00:28:19,630
creating a super hot blue ball of gas,
464
00:28:19,630 --> 00:28:23,630
a newborn star.
465
00:28:23,640 --> 00:28:25,570
Just think about how cool that is.
466
00:28:25,570 --> 00:28:28,840
In the constellation Cygnus, in about five years' time,
467
00:28:28,840 --> 00:28:33,140
a new star is gonna turn on created from two older stars...
468
00:28:33,140 --> 00:28:36,550
An entirely new way of seeing a star being born.
469
00:28:39,650 --> 00:28:41,020
Around the star,
470
00:28:41,020 --> 00:28:43,950
searing-hot gas will expand outwards,
471
00:28:43,960 --> 00:28:48,260
turning red as it cools, becoming the red Nova.
472
00:28:54,170 --> 00:28:57,530
The explosion will create a brand-new light
473
00:28:57,540 --> 00:29:01,200
as bright as the north star in our night sky.
474
00:29:03,510 --> 00:29:06,440
It's just phenomenal that we get this opportunity.
475
00:29:06,440 --> 00:29:09,980
This is what every astronomer wants to do.
476
00:29:12,020 --> 00:29:13,720
We are at a safe distance
477
00:29:13,720 --> 00:29:16,050
from this colliding star duo.
478
00:29:18,020 --> 00:29:21,920
But would we feel the same way if we were on a planet
479
00:29:21,930 --> 00:29:24,630
orbiting this binary system.
480
00:29:24,630 --> 00:29:27,600
This is a very, very energetic event.
481
00:29:27,600 --> 00:29:31,030
Could life survive such an event?
482
00:29:31,040 --> 00:29:34,040
I wouldn't want to be there as the test Guinea pig.
483
00:29:37,680 --> 00:29:39,680
All this energy comes pouring in,
484
00:29:39,680 --> 00:29:43,210
and your atmosphere is likely to be stripped away.
485
00:29:43,210 --> 00:29:45,480
If there are oceans on this world,
486
00:29:45,480 --> 00:29:47,620
they're likely to be vaporized,
487
00:29:47,620 --> 00:29:51,650
and there may be very little left other than rock.
488
00:29:51,660 --> 00:29:53,920
A Nova is nothing you want to fool around with.
489
00:29:53,930 --> 00:29:56,790
Any planet that's close by is gonna get cooked.
490
00:29:56,790 --> 00:30:00,700
It's gonna get sandblasted, and then, you know, there it is.
491
00:30:00,700 --> 00:30:02,570
If that's the kind of place you want to be,
492
00:30:02,570 --> 00:30:05,600
hey, more power to you, but I like earth.
493
00:30:09,710 --> 00:30:12,380
Earth has a good thing going these days
494
00:30:12,380 --> 00:30:14,680
with our single star.
495
00:30:14,680 --> 00:30:20,950
No collisions, no explosions, no drama.
496
00:30:20,950 --> 00:30:23,520
For two stars to be better than one,
497
00:30:23,520 --> 00:30:27,220
we need to find rocky planets in a binary system.
498
00:30:29,990 --> 00:30:34,660
But so far, we haven't, raising the question...
499
00:30:34,670 --> 00:30:37,930
Can they really exist at all?
500
00:30:56,150 --> 00:30:58,720
The Kepler space telescope
501
00:30:58,720 --> 00:31:01,990
has blown the search for alien worlds wide open,
502
00:31:01,990 --> 00:31:05,020
discovering thousands of exoplanets
503
00:31:05,020 --> 00:31:07,260
orbiting single stars.
504
00:31:11,030 --> 00:31:14,330
But finding rocky planets in binary systems
505
00:31:14,330 --> 00:31:16,270
is proving difficult.
506
00:31:19,740 --> 00:31:22,570
We have found planets orbiting binary star systems,
507
00:31:22,580 --> 00:31:24,940
and that's a big leap forward in our understanding
508
00:31:24,940 --> 00:31:26,480
of how the universe works.
509
00:31:26,480 --> 00:31:29,780
Unfortunately, those planets have all been gas giants,
510
00:31:29,780 --> 00:31:33,750
and they're not really good for forming life.
511
00:31:33,750 --> 00:31:37,690
For alien civilizations to exist around two suns,
512
00:31:37,690 --> 00:31:39,790
they need solid ground.
513
00:31:39,790 --> 00:31:43,430
The hunt for the world of our Sci-Fi dreams
514
00:31:43,430 --> 00:31:46,660
has so far been fruitless.
515
00:31:46,670 --> 00:31:49,730
We always have to consider that maybe rocky planets
516
00:31:49,740 --> 00:31:51,340
around binary stars
517
00:31:51,340 --> 00:31:54,540
just don't exist for some reason that we currently don't know.
518
00:31:54,540 --> 00:31:59,280
And that would mean there would be no Tatooine.
519
00:31:59,280 --> 00:32:02,250
Could paired stars make it impossible
520
00:32:02,250 --> 00:32:04,350
for a rocky planet to form.
521
00:32:07,120 --> 00:32:09,890
If you're a planet trying to form around a binary system,
522
00:32:09,890 --> 00:32:12,490
the gravity in the middle is always changing.
523
00:32:12,490 --> 00:32:14,590
Instead of a single star, you have two stars
524
00:32:14,590 --> 00:32:18,200
orbiting each other.
525
00:32:18,200 --> 00:32:21,170
These two infant stars
526
00:32:21,170 --> 00:32:24,570
start a gravitational tug-of-war.
527
00:32:24,570 --> 00:32:28,640
The material between them is pulled in different directions,
528
00:32:28,640 --> 00:32:32,940
making it harder for bits of rock and dust to stick together.
529
00:32:32,950 --> 00:32:39,320
The system seems too chaotic for rocky planets to form.
530
00:32:39,320 --> 00:32:42,150
The complex gravitational interactions
531
00:32:42,160 --> 00:32:45,960
at play destabilize a lot of potential orbits.
532
00:32:45,960 --> 00:32:49,630
There aren't a lot of opportunities for a young planet
533
00:32:49,630 --> 00:32:53,830
that might want to form to find a stable, long-term home
534
00:32:53,830 --> 00:32:57,400
that lasts for billions of years around that binary system.
535
00:32:57,400 --> 00:33:01,910
It's relatively easy to get ejected or consumed
536
00:33:01,910 --> 00:33:04,110
by the stars themselves.
537
00:33:06,180 --> 00:33:08,880
So, why can't rocky planets survive
538
00:33:08,880 --> 00:33:11,680
when gas giants can?
539
00:33:11,680 --> 00:33:15,620
As any good realtor will tell you, it's all about
540
00:33:15,620 --> 00:33:19,860
location, location, location.
541
00:33:19,860 --> 00:33:23,730
We think that rocky planets tend to form close in around stars
542
00:33:23,730 --> 00:33:26,130
where it's nice and warm, but further out where it's colder,
543
00:33:26,130 --> 00:33:28,270
you have the gas giant planets forming.
544
00:33:28,270 --> 00:33:30,230
So, if you have a binary star system,
545
00:33:30,240 --> 00:33:32,740
it's like a gravitational tornado whipping out
546
00:33:32,740 --> 00:33:34,470
all of that rocky material
547
00:33:34,470 --> 00:33:36,610
so that you're only left with the cold stuff,
548
00:33:36,610 --> 00:33:39,380
which can form gas giants further out.
549
00:33:39,380 --> 00:33:42,050
If a two-star system were a city,
550
00:33:42,050 --> 00:33:45,480
the gas giants are out in the suburbs.
551
00:33:45,490 --> 00:33:49,550
A nice, peaceful spot away from the competing gravity
552
00:33:49,560 --> 00:33:52,960
of the two stars.
553
00:33:52,960 --> 00:33:57,830
Perhaps one-star systems are better than two.
554
00:33:57,830 --> 00:34:00,430
Gas giants aren't great for life,
555
00:34:00,430 --> 00:34:06,470
and those are the planets we're finding in these binary systems.
556
00:34:06,470 --> 00:34:08,640
The very reason that we're here could be down to the fact
557
00:34:08,640 --> 00:34:10,670
that we have one star rather than two.
558
00:34:13,980 --> 00:34:15,780
But in 2017,
559
00:34:15,780 --> 00:34:19,620
a discovery around 2,000 light years away
560
00:34:19,620 --> 00:34:22,820
gives us new hope.
561
00:34:22,820 --> 00:34:25,620
So, as we discover new things in the universe,
562
00:34:25,630 --> 00:34:28,030
we tend to give them catalogue names,
563
00:34:28,030 --> 00:34:29,690
which can be very boring
564
00:34:29,700 --> 00:34:32,260
and very difficult to keep track of.
565
00:34:32,270 --> 00:34:36,400
But SDSS 1557 is worth remembering.
566
00:34:38,800 --> 00:34:41,610
We've seen a binary system that is a white dwarf...
567
00:34:41,610 --> 00:34:43,910
Which is the core of a star like the sun
568
00:34:43,910 --> 00:34:45,440
after it's gotten very old,
569
00:34:45,440 --> 00:34:48,910
blown off its outer layers... That's orbited by a brown dwarf,
570
00:34:48,920 --> 00:34:50,310
an object which is sort of on the border
571
00:34:50,320 --> 00:34:52,850
between a planet and a star.
572
00:34:52,850 --> 00:34:58,320
What's most exciting about the SDSS 1557 system
573
00:34:58,320 --> 00:35:02,730
is that we've found rocky debris.
574
00:35:02,730 --> 00:35:04,330
We see the basic materials,
575
00:35:04,330 --> 00:35:07,770
the basic ingredients are there for forming planets.
576
00:35:07,770 --> 00:35:09,270
This is a really exciting discovery
577
00:35:09,270 --> 00:35:11,370
because we've seen the remnants of asteroids
578
00:35:11,370 --> 00:35:14,840
and rocks orbiting about this ancient binary system,
579
00:35:14,840 --> 00:35:18,210
systems that we thought could've never had surviving
580
00:35:18,210 --> 00:35:20,610
rocky-type things around it before.
581
00:35:22,680 --> 00:35:26,720
This binary system is billions of years old,
582
00:35:26,720 --> 00:35:28,690
and through all that time,
583
00:35:28,690 --> 00:35:33,390
the rocky material hasn't been wiped out.
584
00:35:33,390 --> 00:35:35,630
It has survived.
585
00:35:35,630 --> 00:35:40,300
This is a huge stepping stone to finding our rocky planet
586
00:35:40,300 --> 00:35:43,770
with two suns.
587
00:35:43,770 --> 00:35:46,100
The system provides evidence there's rocky material
588
00:35:46,110 --> 00:35:48,970
close in around a binary star system,
589
00:35:48,980 --> 00:35:51,940
so it's a signpost that rocky planet formation
590
00:35:51,940 --> 00:35:55,310
can occur around binary star systems.
591
00:35:55,310 --> 00:35:59,650
The odds might be longer, but it's still possible.
592
00:35:59,650 --> 00:36:04,490
Could there even still be a planet in this system?
593
00:36:04,490 --> 00:36:09,290
There may still be planetary objects around SDS 1557.
594
00:36:09,300 --> 00:36:12,200
We just haven't seen them yet, but they may still be there.
595
00:36:18,800 --> 00:36:22,270
The search is still on.
596
00:36:22,280 --> 00:36:26,910
A rocky planet orbiting two stars could really exist.
597
00:36:28,950 --> 00:36:31,550
So, for those of us hoping for that Tatooine out there,
598
00:36:31,550 --> 00:36:33,720
that planet with the double sunset,
599
00:36:33,720 --> 00:36:36,050
these debris fields actually give us hope.
600
00:36:36,060 --> 00:36:39,090
Maybe the conditions, at least, are right for the formation
601
00:36:39,090 --> 00:36:42,260
of rocky planets around binary stars.
602
00:36:42,260 --> 00:36:43,630
I think it's out there.
603
00:36:43,630 --> 00:36:46,700
I think finding it is more a question of when than if.
604
00:36:46,700 --> 00:36:50,430
As an astronomer, this is a fantastic time to be alive
605
00:36:50,440 --> 00:36:52,070
at the cusp of discovery.
606
00:36:52,070 --> 00:36:55,670
As a science fiction fan, this is a fantastic time to be alive
607
00:36:55,680 --> 00:36:58,410
because the stuff I read as a kid is coming true.
608
00:37:01,010 --> 00:37:04,720
But perhaps the biggest Sci-Fi fantasy
609
00:37:04,720 --> 00:37:07,950
is much closer to home,
610
00:37:07,950 --> 00:37:12,590
because new research is suggesting something stunning...
611
00:37:12,590 --> 00:37:16,530
Our own sun could have a twin.
612
00:37:35,480 --> 00:37:39,680
A new study in 2017 throws into question
613
00:37:39,680 --> 00:37:42,110
our understanding of the sun.
614
00:37:46,190 --> 00:37:48,690
For the first time now, astronomers are able to peer
615
00:37:48,690 --> 00:37:51,420
inside the clouds that form stars,
616
00:37:51,430 --> 00:37:54,330
and the amazing thing is that the evidence is suggesting
617
00:37:54,330 --> 00:37:58,360
that every single sun-like star forms as part of a binary pair.
618
00:38:00,200 --> 00:38:04,700
The scientists study the Perseus molecular cloud,
619
00:38:04,710 --> 00:38:08,610
a stellar nursery around 750 light years from us,
620
00:38:08,610 --> 00:38:11,540
packed with stars just like our sun.
621
00:38:14,250 --> 00:38:17,350
Many of them are in wide binary systems,
622
00:38:17,350 --> 00:38:20,120
traveling in huge orbits around each other
623
00:38:20,120 --> 00:38:24,560
that span centuries or more.
624
00:38:24,560 --> 00:38:28,030
And all of these binaries are babies,
625
00:38:28,030 --> 00:38:32,360
less than 500,000 years old.
626
00:38:32,370 --> 00:38:35,630
The only way to explain these young systems
627
00:38:35,640 --> 00:38:41,510
is that they formed this way... Not alone, but in a pair.
628
00:38:45,550 --> 00:38:48,350
Just based on statistics and our understanding
629
00:38:48,350 --> 00:38:50,950
of what's going on inside these star-forming clouds,
630
00:38:50,950 --> 00:38:53,990
it is highly likely that the sun formed with a twin.
631
00:38:56,620 --> 00:38:59,830
Perhaps 4.5 billion years ago,
632
00:38:59,830 --> 00:39:02,990
our sun burst into life with a sibling.
633
00:39:05,230 --> 00:39:07,700
Could this twin still be out there
634
00:39:07,700 --> 00:39:11,070
in a distant orbit that we haven't seen?
635
00:39:13,340 --> 00:39:16,710
There was an idea that the sun could have a companion,
636
00:39:16,710 --> 00:39:18,580
which was nicknamed Nemesis,
637
00:39:18,580 --> 00:39:21,480
and this thing would've orbited way far out,
638
00:39:21,480 --> 00:39:25,420
way past Neptune in the solar system.
639
00:39:25,420 --> 00:39:29,150
Scientists searched for this Nemesis star,
640
00:39:29,160 --> 00:39:32,590
but they came back empty handed.
641
00:39:32,590 --> 00:39:35,930
We've looked... we've had telescopic surveys of the sky,
642
00:39:35,930 --> 00:39:39,030
including infrared surveys where these types of objects
643
00:39:39,030 --> 00:39:40,800
would be very bright,
644
00:39:40,800 --> 00:39:44,670
and we've swept the entire sky multiple times
645
00:39:44,670 --> 00:39:46,740
and we've seen nothing.
646
00:39:50,540 --> 00:39:55,780
What happened to our sun's sibling is a mystery.
647
00:39:55,780 --> 00:39:59,720
How do we end up with one star as opposed to binary?
648
00:39:59,720 --> 00:40:02,850
We really don't quite understand.
649
00:40:02,860 --> 00:40:04,790
If it doesn't orbit us now,
650
00:40:04,790 --> 00:40:09,230
it may have left our system long ago.
651
00:40:09,230 --> 00:40:11,460
Over time, some of these binary stars
652
00:40:11,470 --> 00:40:13,670
get closer together and stay together,
653
00:40:13,670 --> 00:40:16,740
and others get ripped apart and lose each other entirely.
654
00:40:16,740 --> 00:40:20,440
It's very possible that our sun, at some point,
655
00:40:20,440 --> 00:40:24,480
had a twin that got ejected.
656
00:40:24,480 --> 00:40:26,610
We don't know exactly when
657
00:40:26,610 --> 00:40:28,410
our sister star was torn away.
658
00:40:28,420 --> 00:40:30,680
It could be clear on the other side of the galaxy
659
00:40:30,680 --> 00:40:33,950
from us by now.
660
00:40:33,950 --> 00:40:37,960
But after everything we've seen in binary systems,
661
00:40:37,960 --> 00:40:40,630
we may be much better off without it.
662
00:40:42,660 --> 00:40:44,500
I'm pretty happy with having just one sun,
663
00:40:44,500 --> 00:40:48,630
so I'm fine to live in this solar system.
664
00:40:48,640 --> 00:40:51,400
A binary sunset would be more beautiful,
665
00:40:51,410 --> 00:40:55,070
but only more beautiful if you were alive.
666
00:40:55,080 --> 00:40:57,310
And yet binary stars
667
00:40:57,310 --> 00:41:00,410
don't just bring death and destruction.
668
00:41:00,410 --> 00:41:02,780
They could also create systems
669
00:41:02,780 --> 00:41:07,320
with a series of habitable worlds.
670
00:41:07,320 --> 00:41:09,820
There's so much we don't know about our own environment
671
00:41:09,820 --> 00:41:12,460
and how it compares to other places in the universe.
672
00:41:12,460 --> 00:41:14,590
It seems like we're in a very lucky place.
673
00:41:14,590 --> 00:41:17,360
The sun is very stable, it's a single star,
674
00:41:17,360 --> 00:41:19,230
we're in a nice orbit around it,
675
00:41:19,230 --> 00:41:21,830
but maybe there are places out there that are even better.
676
00:41:21,840 --> 00:41:23,670
We just didn't even know to ask.
677
00:41:25,870 --> 00:41:28,410
It's certainly possible
678
00:41:28,410 --> 00:41:31,640
that two stars are better for life than one,
679
00:41:31,650 --> 00:41:35,480
but until we find these alien worlds,
680
00:41:35,480 --> 00:41:38,550
it remains an open question.
681
00:41:41,090 --> 00:41:43,520
It's hard to say whether we're lucky or unlucky
682
00:41:43,520 --> 00:41:45,560
to be on a planet orbiting a single star.
683
00:41:45,560 --> 00:41:47,790
It's probably a little boring here
684
00:41:47,790 --> 00:41:50,160
compared to what it would seem like
685
00:41:50,160 --> 00:41:52,360
in these binary star systems.
686
00:41:55,040 --> 00:41:57,940
You know, from a romantic, visual perspective,
687
00:41:57,940 --> 00:42:01,910
I kind of wish we did live in a binary star system.
688
00:42:01,910 --> 00:42:05,180
Can you imagine somebody living on a circum-binary planet
689
00:42:05,180 --> 00:42:08,450
and finding an earthlike planet orbiting a solitary star.
690
00:42:08,450 --> 00:42:10,280
Would they think, "oh, how interesting that would be.
691
00:42:10,280 --> 00:42:12,950
Can you imagine having one sunset?
692
00:42:12,950 --> 00:42:14,150
What would that look like?"
693
00:42:14,150 --> 00:42:16,250
I can imagine them asking themselves
694
00:42:16,260 --> 00:42:18,490
the questions we ask ourselves.
695
00:42:18,490 --> 00:42:20,790
So it's just a matter of perspective, you know?
696
00:42:20,790 --> 00:42:23,760
Grass is always greener on the other side of the binary system.
55468
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.