1
00:00:04,472 --> 00:00:08,640
:
the fate of our galaxy
hangs on the swing,
2
00:00:08,642 --> 00:00:14,880
the milky way is dying,
and we don't know why,
3
00:00:14,882 --> 00:00:19,785
our galaxy, like all galaxies,
has a limited service life,
4
00:00:19,787 --> 00:00:23,622
After that, it's lights out,
5
00:00:23,624 --> 00:00:26,492
:the race is on
to find a smoking gun,
6
00:00:28,829 --> 00:00:32,598
It's safe to say right now
There are many ways to kill a galaxy,
7
00:00:35,803 --> 00:00:39,738
:it's a cosmic
crime scene investigation,
8
00:00:39,740 --> 00:00:42,908
Is murder worse?
9
00:00:42,910 --> 00:00:45,010
or is it
death from natural causes?
10
00:00:47,314 --> 00:00:49,782
:
the suspects are lined up,
11
00:00:49,784 --> 00:00:52,251
interrogation is ongoing,
12
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is another example of this great
our universe
13
00:00:58,559 --> 00:01:01,093
throwing riddles at us
that we now have to resolve,
14
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:
what is killing the milky way?
15
00:01:13,274 --> 00:01:23,282
♪♪
16
00:01:23,284 --> 00:01:25,517
♪♪
17
00:01:25,519 --> 00:01:27,853
earth,
18
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our home,
19
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just one of 100 billion planets
20
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orbiting 400 billion stars
21
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which constitute an immense
galactic spiral,
22
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,the Milky Way,
23
00:01:49,877 --> 00:01:52,478
thaller:
Galaxies are where stars form,
24
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and of course,
Planets form stars,
25
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then the history of the earth,
26
00:01:56,650 --> 00:01:58,884
of yourself,
of the solar system
27
00:01:58,886 --> 00:02:02,321
has everything to do
with the history of galaxies,
28
00:02:05,626 --> 00:02:10,863
:
the history of the milky way
begins 13.6 billion years ago,
29
00:02:10,865 --> 00:02:13,465
right after the big bang,
30
00:02:13,467 --> 00:02:17,536
It's a time when there is
no planets and no stars -
31
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just a vast, lumpy soup
of superheated hydrogen,
32
00:02:25,479 --> 00:02:28,647
over millions of years,
the temperature drops
33
00:02:28,649 --> 00:02:33,051
and gravity compresses
the pieces fall, until eventually
34
00:02:33,053 --> 00:02:37,856
hydrogen fusions fuse
and light a star,
35
00:02:42,329 --> 00:02:47,833
in time, billions of stars
explode into life,
36
00:02:47,835 --> 00:02:51,103
and the milky way
begins to take shape,
37
00:02:51,105 --> 00:02:56,175
♪♪
38
00:02:56,177 --> 00:02:58,911
you can think of a galaxy
as a type of human being,
39
00:02:58,913 --> 00:03:01,346
when you are young and in your
teenage stage,
40
00:03:01,348 --> 00:03:02,814
You are vibrant and active,
41
00:03:02,816 --> 00:03:05,584
This is a young galaxy
forming stars in a crazy way,
42
00:03:05,586 --> 00:03:07,219
and it's not
even fully formed,
43
00:03:07,221 --> 00:03:09,888
at a certain point,
galaxy reaches the middle ages
44
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and a really middle-aged galaxy
That's what it's going to be -
45
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has its shape -
46
00:03:13,794 --> 00:03:17,062
but in the long run, a galaxy
will stop forming stars,
47
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and eventually, just like us
Everyone dies, our galaxy will die,
48
00:03:24,004 --> 00:03:27,806
:
So, at what stage of life
Is it the milky way?
49
00:03:27,808 --> 00:03:30,409
is it healthy?
active young man
50
00:03:30,411 --> 00:03:32,578
or are you going
by your deathbed?
51
00:03:35,783 --> 00:03:39,518
scientists can determine
stage of life of each galaxy
52
00:03:39,520 --> 00:03:42,387
for its color,
53
00:03:42,389 --> 00:03:47,226
Sutter:
so we see different colors
of galaxies in the universe,
54
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we see galaxies
which are tinted blue
55
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and galaxies
which are red paints,
56
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when we see a blue galaxy, this
tends to be a younger galaxy
57
00:03:59,707 --> 00:04:04,009
full of light,
hot, newly formed stars,
58
00:04:06,480 --> 00:04:08,647
when we see a redder galaxy,
59
00:04:08,649 --> 00:04:11,817
that tends
To be a dimmer, older galaxy
60
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this is not forming new stars
at the present moment,
61
00:04:15,656 --> 00:04:18,857
all the stars are aged
and older and redder
62
00:04:18,859 --> 00:04:22,494
and so the whole galaxy
casts a different tone,
63
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♪♪
64
00:04:27,868 --> 00:04:32,804
:
So, what color is our galaxy?
65
00:04:32,806 --> 00:04:38,777
It's a simple question, but the
The answer is hard to find,
66
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even though we were looking
the dairy way
67
00:04:41,715 --> 00:04:44,783
for thousands of years,
68
00:04:44,785 --> 00:04:46,852
The term "milky path" is old,
69
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it goes back to a moment
when in the dark sky,
70
00:04:49,056 --> 00:04:51,290
people noticed
there was this band of light
71
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that it really was
from horizon to horizon,
72
00:04:53,627 --> 00:04:54,860
and this band ended
73
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to be made of thousands
and thousands of stars
74
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actually very far away
to view individually,
75
00:04:59,800 --> 00:05:01,600
but it took us
too long to realize
76
00:05:01,602 --> 00:05:06,538
what shape and scale
of the Milky Way Galaxy is,
77
00:05:06,540 --> 00:05:09,408
the wonderful thing to think
is that we don't actually know
78
00:05:09,410 --> 00:05:11,710
our home galaxy
very well,
79
00:05:11,712 --> 00:05:15,414
In fact, we live in the middle
of this disk of gas and dust,
80
00:05:15,416 --> 00:05:19,418
and this clouds our view of
the most dairy way,
81
00:05:19,420 --> 00:05:21,987
using visible light,
we can't even look at the center,
82
00:05:21,989 --> 00:05:26,158
much less the other side
of the milky way galaxy,
83
00:05:30,164 --> 00:05:32,764
:the solution
is to use a form of light
84
00:05:32,766 --> 00:05:36,735
passing through the gas
and dust -
85
00:05:36,737 --> 00:05:38,303
infrared,
86
00:05:41,809 --> 00:05:45,677
this is sloan
digital sky survey telescope
87
00:05:45,679 --> 00:05:50,115
at Apache Point Observatory
in new mexico,
88
00:05:50,117 --> 00:05:53,418
is mapping the galaxy
using infrared
89
00:05:53,420 --> 00:05:57,189
and giving scientists
unprecedented insights,
90
00:05:59,793 --> 00:06:02,994
the first sensitive infrared
observations were not actually made
91
00:06:02,996 --> 00:06:04,963
until the last 15 years,
92
00:06:04,965 --> 00:06:07,265
and each of these new Windows
in the universe
93
00:06:07,267 --> 00:06:09,067
Teach us different things,
94
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♪♪
95
00:06:14,141 --> 00:06:15,707
:
in the last 15 years,
96
00:06:15,709 --> 00:06:21,046
Sloan researched
more than 250 million stars,
97
00:06:21,048 --> 00:06:26,318
Analyzing light for work
the color of the milky way,
98
00:06:26,320 --> 00:06:30,522
and what scientists
surprised them,
99
00:06:30,524 --> 00:06:32,758
until very recently,
we think that the milky way
100
00:06:32,760 --> 00:06:34,760
it was a young and healthy galaxy,
101
00:06:34,762 --> 00:06:36,228
but now there is evidence
102
00:06:36,230 --> 00:06:39,664
so we can enter
the path to death,
103
00:06:41,969 --> 00:06:46,505
:
The Sloan Telescope reveals that
star production in our galaxy
104
00:06:46,507 --> 00:06:49,508
is falling to the ground,
105
00:06:49,510 --> 00:06:52,477
The milky way is dying,
106
00:06:52,479 --> 00:06:56,148
and when it stops
forming new stars,
107
00:06:56,150 --> 00:06:57,716
your time will be ready,
108
00:07:00,187 --> 00:07:02,754
paradoxically,
our galaxy still has
109
00:07:02,756 --> 00:07:08,693
star-forming gas in the tank,
so it must be healthy,
110
00:07:08,695 --> 00:07:11,196
But something is killing it,
111
00:07:15,335 --> 00:07:18,036
So, the milky way galaxy
This wonderful album
112
00:07:18,038 --> 00:07:21,907
filled with hydrogen-rich gas,
many clouds of dense dust,
113
00:07:21,909 --> 00:07:24,509
has everything you need there
for star formation
114
00:07:24,511 --> 00:07:27,846
but it seems to be decreasing
and even turn off,
115
00:07:27,848 --> 00:07:31,516
and right now, not really
understand what is to blame,
116
00:07:36,156 --> 00:07:38,056
:
with a galaxy killer in general,
117
00:07:38,058 --> 00:07:42,260
scientists embark
largest murder investigation
118
00:07:42,262 --> 00:07:44,429
in history
From the universe,
119
00:07:46,400 --> 00:07:48,500
everything in science,
when you are exploring a problem,
120
00:07:48,502 --> 00:07:50,802
It's a bit like a crime scene,
121
00:07:50,804 --> 00:07:53,038
you got the evidence
placed in front of you,
122
00:07:57,177 --> 00:08:00,345
, and we have to
find out who did it,
123
00:08:01,548 --> 00:08:10,388
♪
124
00:08:10,390 --> 00:08:14,392
:
our home in the universe
is dying --
125
00:08:14,394 --> 00:08:20,765
not the earth
but our galaxy, the milky way,
126
00:08:20,767 --> 00:08:24,302
has produced stars
for billions of years,
127
00:08:24,304 --> 00:08:26,771
But soon, it will stop,
128
00:08:28,842 --> 00:08:31,510
our own sun formed
about 4 1/2 billion years ago
129
00:08:31,512 --> 00:08:32,911
in the way of the Milky Way,
130
00:08:32,913 --> 00:08:36,181
and we are not
the oldest star by far,
131
00:08:36,183 --> 00:08:38,383
and yet, tragically,
In fact, we seem to be
132
00:08:38,385 --> 00:08:42,120
one of the last generations
of new stars in the milky way,
133
00:08:42,122 --> 00:08:45,557
current projections suggest
that in about 4 billion years,
134
00:08:45,559 --> 00:08:47,559
star formation may have
they all stopped together
135
00:08:47,561 --> 00:08:49,427
which is almost just
a blink of an eye
136
00:08:49,429 --> 00:08:51,329
in the life cycle
From the universe,
137
00:08:55,702 --> 00:08:59,671
:
to find out why, scientists
start an investigation,
138
00:08:59,673 --> 00:09:01,973
the most important question?
139
00:09:01,975 --> 00:09:04,843
How can you die?
140
00:09:06,680 --> 00:09:09,915
to kill a galaxy, you have
to get rid of the cold gas,
141
00:09:09,917 --> 00:09:12,117
because this is
what stars form from,
142
00:09:12,119 --> 00:09:13,585
there are many paths
can you do this,
143
00:09:13,587 --> 00:09:15,687
you can explode
from within,
144
00:09:15,689 --> 00:09:17,889
you can draw it
from outside,
145
00:09:17,891 --> 00:09:20,292
you can heat it
so it's not cold anymore,
146
00:09:20,294 --> 00:09:21,793
you can use everything,
147
00:09:21,795 --> 00:09:23,929
and there are even more ways
can you stop it,
148
00:09:23,931 --> 00:09:25,497
what do we have to do
is to discover
149
00:09:25,499 --> 00:09:28,099
where is it happening from
in our galaxy,
150
00:09:30,671 --> 00:09:36,207
:
Maybe the culprit is inside
the milky way itself,
151
00:09:36,209 --> 00:09:39,611
a clue comes from
another whole galaxy,
152
00:09:41,648 --> 00:09:48,453
this is w2246-0526,
153
00:09:48,455 --> 00:09:52,457
scientists call it heat,
galaxy obscured by dust
154
00:09:52,459 --> 00:09:54,826
or "hot dog" down,
155
00:09:57,598 --> 00:10:00,699
this galaxy is
12 billion light years away,
156
00:10:00,701 --> 00:10:03,568
is the most luminous galaxy
We met in the universe,
157
00:10:03,570 --> 00:10:06,705
has the light
of 300 trillion stars,
158
00:10:10,978 --> 00:10:14,679
:
The source of the intense light
It's not your stars,
159
00:10:14,681 --> 00:10:19,684
but a mysterious object
at the center of the galaxy,
160
00:10:19,686 --> 00:10:23,188
is a million times smaller
than the galaxy itself,
161
00:10:25,926 --> 00:10:29,761
there is only one thing
how small and powerful,
162
00:10:32,466 --> 00:10:34,699
,a supermassive black hole,
163
00:10:38,538 --> 00:10:41,640
So, supermassive black holes,
as the name suggests,
164
00:10:41,642 --> 00:10:43,174
are really supermassive,
165
00:10:43,176 --> 00:10:47,579
these are billions of times
more massive than our sun,
166
00:10:47,581 --> 00:10:49,648
These are gigantic objects,
167
00:10:52,552 --> 00:10:56,721
:
gravity in the supermassive
The black hole is off the charts,
168
00:11:00,260 --> 00:11:02,327
it's shit
incredible amounts
169
00:11:02,329 --> 00:11:05,664
of hot dogs
vital star-forming gas,
170
00:11:09,703 --> 00:11:12,237
and how the gas burns
to form a disk,
171
00:11:12,239 --> 00:11:16,174
overheating from intense friction
to millions of degrees
172
00:11:16,176 --> 00:11:20,945
and, in some galaxies,
unleashes huge jets,
173
00:11:20,947 --> 00:11:23,348
when a lot of material falls
in that black hole,
174
00:11:23,350 --> 00:11:25,750
creates incredibly
energetic jets
175
00:11:25,752 --> 00:11:28,653
which could be tens of thousands
of light years,
176
00:11:28,655 --> 00:11:30,722
suddenly,
you have this sergeant
177
00:11:30,724 --> 00:11:33,391
in the middle of the galaxy,
178
00:11:33,393 --> 00:11:35,627
Bullock: black hole jets
are bad for galaxies
179
00:11:35,629 --> 00:11:37,762
because they can turn off
star formation,
180
00:11:37,764 --> 00:11:40,365
they can heat gas,
take gas from galaxies,
181
00:11:40,367 --> 00:11:41,933
and they really could kill them,
182
00:11:44,271 --> 00:11:47,839
:
a supermassive black hole
is cooking the hot dog,
183
00:11:51,278 --> 00:11:53,044
What is happening in our galaxy?
184
00:11:53,046 --> 00:12:02,487
♪♪
185
00:12:02,489 --> 00:12:06,658
In 2016, Harvard scientists
uncovered damning evidence
186
00:12:06,660 --> 00:12:10,095
that can bind the dairy way
supermassive black hole
187
00:12:10,097 --> 00:12:11,863
at the end of the galaxy,
188
00:12:14,868 --> 00:12:16,334
just like the hot dog,
189
00:12:16,336 --> 00:12:20,438
the milky way is surrounded by
a vast cloud of exploded gas,
190
00:12:22,576 --> 00:12:27,846
and scientists tracked
the gas back to its source -
191
00:12:27,848 --> 00:12:32,784
sagittarius a-star,
our supermassive black hole,
192
00:12:35,789 --> 00:12:37,889
well, it's over
our supermassive black hole
193
00:12:37,891 --> 00:12:41,459
had a bit of a hiccup about
6 million years ago,
194
00:12:41,461 --> 00:12:44,295
there is evidence that
something must have fallen
195
00:12:44,297 --> 00:12:46,798
in that black hole,
and if it fell too quickly,
196
00:12:46,800 --> 00:12:49,868
would have overcome the warming
by your own friction,
197
00:12:49,870 --> 00:12:54,672
and that would have acted,
in a sense, like an explosion,
198
00:12:54,674 --> 00:12:57,008
oluseyi:
and this event was huge,
199
00:12:57,010 --> 00:13:00,445
our galaxy expelled
an incredible amount of gas -
200
00:13:00,447 --> 00:13:03,882
130 billion times
the mass of the sun,
201
00:13:03,884 --> 00:13:05,750
large amount of gas,
202
00:13:08,688 --> 00:13:10,688
stern:this event must have been
very catastrophic
203
00:13:10,690 --> 00:13:13,424
for the internal parts
of the galaxy,
204
00:13:13,426 --> 00:13:16,161
Fortunately, the Earth is in
the outer parts of the galaxy,
205
00:13:16,163 --> 00:13:18,563
where we were able
to survive this event,
206
00:13:22,402 --> 00:13:25,370
:
Is that the smoking gun?
207
00:13:25,372 --> 00:13:30,508
It's our own supermassive black
hole killing the milky way?
208
00:13:30,510 --> 00:13:32,777
The evidence seems to increase,
209
00:13:35,348 --> 00:13:39,317
but sagittarius a-star
has an alibi,
210
00:13:39,319 --> 00:13:42,520
exploded too late,
211
00:13:42,522 --> 00:13:45,390
sagittarius a-star
became very active
212
00:13:45,392 --> 00:13:47,826
very explosive
About 6 million years ago,
213
00:13:47,828 --> 00:13:50,295
but it's so recent, that
shouldn't have really affected
214
00:13:50,297 --> 00:13:51,729
star formation rates,
215
00:13:51,731 --> 00:13:53,097
something else is happening,
216
00:13:53,099 --> 00:13:55,967
there must be another culprit
beyond the black hole,
217
00:13:58,171 --> 00:14:02,207
:
studies suggest our supermassive
black hole must be active
218
00:14:02,209 --> 00:14:04,676
hundreds of millions
from years ago
219
00:14:04,678 --> 00:14:09,147
to stop star formation
in our galaxy,
220
00:14:09,149 --> 00:14:13,017
sagittarius a-star
was not active at that time,
221
00:14:13,019 --> 00:14:15,920
then you are no longer a suspect,
222
00:14:17,991 --> 00:14:21,359
the hunt is on
a different galaxy killer,
223
00:14:21,361 --> 00:14:25,630
and scientists are expanding
the investigation,
224
00:14:25,632 --> 00:14:28,199
maybe the killer
is not within our galaxy,
225
00:14:28,201 --> 00:14:31,402
we may suffer
a hit-and-run,
226
00:14:31,404 --> 00:14:38,676
♪♪
227
00:14:39,913 --> 00:14:49,654
we may suffer
a hit-and-run,
228
00:14:49,656 --> 00:14:53,091
♪♪
229
00:14:53,093 --> 00:14:55,693
:
our universe is a crime scene,
230
00:14:57,998 --> 00:15:03,134
star production in a dairy way
is breaking,
231
00:15:03,136 --> 00:15:05,236
our galaxy is dying,
232
00:15:05,238 --> 00:15:08,873
and astronomers are examining
The body for clues,
233
00:15:11,111 --> 00:15:16,681
the disk of the milky way is composed
of three sections -
234
00:15:16,683 --> 00:15:21,386
a nucleus, the home of the galaxy
supermassive black hole,
235
00:15:24,291 --> 00:15:29,594
,a dense, central prominence
10,000 light years,
236
00:15:29,596 --> 00:15:31,262
and the spiral arms -
237
00:15:31,264 --> 00:15:35,099
full of gas, dust
and billions of stars,
238
00:15:37,170 --> 00:15:41,873
the spiral arms must be flat,
but they are waving,
239
00:15:41,875 --> 00:15:45,143
this is a clue
for cosmic detectives?
240
00:15:46,947 --> 00:15:48,980
ox:
Today, we look to the edge
of the milky way,
241
00:15:48,982 --> 00:15:51,049
and we see mysterious
ripples in your gas,
242
00:15:51,051 --> 00:15:53,251
and we wonder,
What is the origin?
243
00:15:53,253 --> 00:15:55,353
something must have
made this happen,
244
00:15:55,355 --> 00:15:57,822
something similar
It just doesn't happen on its own,
245
00:15:57,824 --> 00:15:59,724
The real question is why?
246
00:16:04,331 --> 00:16:08,900
:
Whatever caused the ripples
didn't walk around,
247
00:16:08,902 --> 00:16:11,936
is this evidence of
a galactic hit-and-run?
248
00:16:15,008 --> 00:16:17,175
January 2016,
249
00:16:20,146 --> 00:16:24,182
astronomers studying data
from the Vista telescope
250
00:16:24,184 --> 00:16:26,184
discover something incredible,
251
00:16:30,290 --> 00:16:32,824
,three stars nearby,
252
00:16:32,826 --> 00:16:35,560
on my own, nothing special,
253
00:16:35,562 --> 00:16:39,163
except they recently
left our galaxy
254
00:16:39,165 --> 00:16:43,735
and they are traveling
at 350,000 miles per hour,
255
00:16:47,507 --> 00:16:49,941
then we discovered these stars
who are carminating
256
00:16:49,943 --> 00:16:52,710
outside the galaxy
at super-high speeds,
257
00:16:52,712 --> 00:16:54,979
these three stars
be responsible in some way
258
00:16:54,981 --> 00:16:56,881
for deformation
The disk of the Milky Way?
259
00:16:56,883 --> 00:16:58,349
well, absolutely not,
260
00:16:58,351 --> 00:17:01,586
the milky way is much more
massive than just three stars,
261
00:17:01,588 --> 00:17:04,989
three stars alone
cannot warp a galaxy,
262
00:17:04,991 --> 00:17:08,359
but these three stars can be
indicative of more stars,
263
00:17:08,361 --> 00:17:10,862
they can be indicative
the presence of, say,
264
00:17:10,864 --> 00:17:14,065
a dwarf galaxy,
and that can deform the galaxy,
265
00:17:16,036 --> 00:17:19,470
:
dwarf galaxies are abundant,
266
00:17:19,472 --> 00:17:22,774
but a small fraction
the size of a large galaxy,
267
00:17:22,776 --> 00:17:24,342
like the milky way,
268
00:17:26,413 --> 00:17:29,781
so they are difficult to detect,
269
00:17:29,783 --> 00:17:33,985
but these three shining stars
show that there is a dwarf galaxy
270
00:17:33,987 --> 00:17:38,289
hiding beyond the edge
of the milky way,
271
00:17:38,291 --> 00:17:41,426
and scientists can study
the trio of stars
272
00:17:41,428 --> 00:17:43,161
to rewind the clock
273
00:17:43,163 --> 00:17:47,365
and trace the past
dwarf galaxy movements,
274
00:17:50,236 --> 00:17:53,037
simulations suggest
that millions of years ago,
275
00:17:53,039 --> 00:17:54,305
this dwarf galaxy
276
00:17:54,307 --> 00:17:56,374
pierced by the plane
of the milky way,
277
00:18:01,314 --> 00:18:06,084
:
like the fast-moving dwarf galaxy
travels through the milky way,
278
00:18:06,086 --> 00:18:11,823
millions of stars seem to be configured
on a collision course,
279
00:18:11,825 --> 00:18:14,158
The catastrophe seems inevitable,
280
00:18:16,062 --> 00:18:19,063
but appearances
may be misleading,
281
00:18:20,934 --> 00:18:23,401
When galaxies collide, the first
thing you can imagine
282
00:18:23,403 --> 00:18:26,037
is that the stars collide, but
In fact, that doesn't happen,
283
00:18:26,039 --> 00:18:27,839
galaxies
are mostly empty space,
284
00:18:27,841 --> 00:18:30,041
if you caught the sun,
what is really great -
285
00:18:30,043 --> 00:18:31,776
It's a million miles away -
286
00:18:31,778 --> 00:18:35,746
and shrunk to size
of a piece of pollen,
287
00:18:35,748 --> 00:18:39,117
The galaxy itself would be twice
the size of the Pacific Ocean,
288
00:18:39,119 --> 00:18:42,587
and the closest star to the sun
would be a mile away,
289
00:18:42,589 --> 00:18:45,756
these little pieces of pollen are
they will never fight,
290
00:18:49,696 --> 00:18:53,831
: the distances involved
are surprising,
291
00:18:53,833 --> 00:18:55,500
and at the moment of impact,
292
00:18:55,502 --> 00:18:58,069
most stars
of the two galaxies
293
00:18:58,071 --> 00:19:00,705
I miss you completely,
294
00:19:00,707 --> 00:19:04,742
but that doesn't mean
The milky way is safe,
295
00:19:06,913 --> 00:19:09,680
Sutter:same as the stars
just pass by,
296
00:19:09,682 --> 00:19:13,518
they do gravitationally
interact as they approach,
297
00:19:13,520 --> 00:19:16,888
and this gravitational
interaction defines them
298
00:19:16,890 --> 00:19:18,489
on a course that is different
299
00:19:18,491 --> 00:19:20,925
than if they were
to live alone,
300
00:19:23,763 --> 00:19:25,863
Bullock: same way
that picking up a stone
301
00:19:25,865 --> 00:19:27,532
and dropping
in a motionless pond
302
00:19:27,534 --> 00:19:29,667
creates ripples in the water,
303
00:19:29,669 --> 00:19:32,336
a galaxy like this that beats
in the milky way
304
00:19:32,338 --> 00:19:34,739
can create ripple effects
across the entire disk,
305
00:19:38,044 --> 00:19:39,710
:
the ripples of the milky way
306
00:19:39,712 --> 00:19:43,114
stretch into tens
thousands of light years,
307
00:19:45,285 --> 00:19:50,621
Still, this hit-and-run is not
enough to kill the milky way,
308
00:19:50,623 --> 00:19:54,292
this only causes a flesh wound,
309
00:19:54,294 --> 00:19:59,797
but what if this dwarf galaxy
Are you not acting alone?
310
00:19:59,799 --> 00:20:01,766
and if he has accomplices?
311
00:20:04,304 --> 00:20:07,038
there are many
dwarf galaxies out there,
312
00:20:07,040 --> 00:20:10,308
and result in collisions
between these dwarf galaxies
313
00:20:10,310 --> 00:20:13,177
and large galaxies, such as
the milky way, are common,
314
00:20:13,179 --> 00:20:14,445
They happen all the time,
315
00:20:14,447 --> 00:20:16,480
now there are
several dwarf galaxies
316
00:20:16,482 --> 00:20:18,516
that the milky way
is swallowing,
317
00:20:18,518 --> 00:20:20,718
In fact, a really fun thing is
that we are really closer
318
00:20:20,720 --> 00:20:22,887
to the core of a
of these galaxies -
319
00:20:22,889 --> 00:20:24,822
the canis majoris
dwarf galaxy -
320
00:20:24,824 --> 00:20:26,657
than we are at the core
of the milky way,
321
00:20:26,659 --> 00:20:29,594
So, some of the stars you
see around you in the night sky
322
00:20:29,596 --> 00:20:32,330
are really stars
from a different galaxy,
323
00:20:32,332 --> 00:20:35,433
So what happens when all these
dwarf galaxies come together
324
00:20:35,435 --> 00:20:38,302
and start pulling and pulling
in a larger galaxy?
325
00:20:38,304 --> 00:20:44,108
♪♪
326
00:20:44,110 --> 00:20:47,945
:
cosmologists believe it could
be hundreds of dwarf galaxies
327
00:20:47,947 --> 00:20:50,481
around the milky way,
328
00:20:53,319 --> 00:20:56,821
a collision with just one of the
these dwarf galaxies
329
00:20:56,823 --> 00:21:00,558
may have rippled the
The spiral arms of the milky way,
330
00:21:02,562 --> 00:21:05,763
but a gang of dwarf galaxies
331
00:21:05,765 --> 00:21:11,269
could have been much larger
and much more deadly effect,
332
00:21:11,271 --> 00:21:13,571
dwarf galaxies and the path
they interact with large galaxies,
333
00:21:13,573 --> 00:21:14,805
like the milky way,
334
00:21:14,807 --> 00:21:17,775
can influence tremendously
change in our universe,
335
00:21:17,777 --> 00:21:20,411
when they crash into a galaxy,
they can change their structure,
336
00:21:20,413 --> 00:21:23,247
the dairy way doesn't seem
everything seems today
337
00:21:23,249 --> 00:21:26,284
without dwarf galaxies,
338
00:21:26,286 --> 00:21:29,020
:
repeated collisions of dwarf galaxies
339
00:21:29,022 --> 00:21:32,723
could have radically changed the
shape of the milky way itself,
340
00:21:35,328 --> 00:21:39,096
its gravitational ruptures
could have created a badge
341
00:21:39,098 --> 00:21:43,167
and possibly fatal feature
in the middle of our galaxy -
342
00:21:43,169 --> 00:21:44,669
the galactic bar,
343
00:21:48,074 --> 00:21:50,341
the center of the milky way
is elongated,
344
00:21:50,343 --> 00:21:52,243
instead of being
sphere-shaped,
345
00:21:52,245 --> 00:21:55,413
It's more shaped like a bar,
and the bar is made of stars
346
00:21:55,415 --> 00:21:59,550
in orbit this
an elongated way,
347
00:21:59,552 --> 00:22:02,420
oluseyi: and this bar can be bad
for the health of the galaxy
348
00:22:02,422 --> 00:22:04,989
because what they do
It is an aid for gas funnel
349
00:22:04,991 --> 00:22:06,824
in the core of the galaxy,
350
00:22:06,826 --> 00:22:11,228
the loss of this gas could be a
way to stop star formation,
351
00:22:14,701 --> 00:22:17,902
:the bar-shaped protuberance
at the center of the milky way
352
00:22:17,904 --> 00:22:20,871
sweeps our galaxy
star building gas
353
00:22:20,873 --> 00:22:23,107
in the galactic core,
354
00:22:23,109 --> 00:22:24,709
here, it is swallowed
355
00:22:24,711 --> 00:22:27,545
by our galaxy
supermassive black hole,
356
00:22:31,617 --> 00:22:35,786
without the construction of stars
material, no new stars can form,
357
00:22:35,788 --> 00:22:39,223
and the galaxy dies,
358
00:22:39,225 --> 00:22:41,258
So, is the case closed?
359
00:22:41,260 --> 00:22:43,828
are dwarf galaxies
killing the milky way?
360
00:22:43,830 --> 00:22:47,865
It's the murder weapon
a galactic bar?
361
00:22:47,867 --> 00:22:50,735
So, it is possible that
the formation of these bars
362
00:22:50,737 --> 00:22:54,438
helps shut down star formation
in the core of the galaxy,
363
00:22:54,440 --> 00:22:57,341
but this is just the central
regions of the galaxy,
364
00:22:57,343 --> 00:22:59,210
that doesn't explain
What's going further
365
00:22:59,212 --> 00:23:01,045
in the spiral arms,
366
00:23:01,047 --> 00:23:04,548
So if star formation really is
hanging up in the milky way,
367
00:23:04,550 --> 00:23:06,851
it's not really
the failure of the bar,
368
00:23:09,021 --> 00:23:13,391
:
dwarf galaxies cause the
Milky way severe bodily harm
369
00:23:13,393 --> 00:23:16,460
creating the galactic bar,
370
00:23:16,462 --> 00:23:21,899
but they're off the hook
for attempted galactic assassination,
371
00:23:21,901 --> 00:23:24,635
the investigation continues,
372
00:23:24,637 --> 00:23:29,840
and it can be about
to take on a dramatic touch,
373
00:23:29,842 --> 00:23:32,109
it may not be that
The galaxy is being murdered,
374
00:23:32,111 --> 00:23:34,412
could just be
eating to death,
375
00:23:34,414 --> 00:23:44,121
♪♪
376
00:23:45,491 --> 00:23:54,532
♪
could just be
eating to death,
377
00:23:54,534 --> 00:23:58,536
:the milky way
is being killed,
378
00:23:58,538 --> 00:24:01,305
and the perpetrator
remains free,
379
00:24:03,476 --> 00:24:05,443
scientists
investigating the crime
380
00:24:05,445 --> 00:24:07,178
are running out of suspects,
381
00:24:09,215 --> 00:24:11,348
but the hunt
because the clues continue,
382
00:24:13,319 --> 00:24:18,556
so astronomers are examining
the dying body of the milky way,
383
00:24:18,558 --> 00:24:21,725
our galaxy is
an obscure disk of stars
384
00:24:21,727 --> 00:24:25,296
surrounded by a halo
of superheated gas,
385
00:24:27,166 --> 00:24:31,135
There are more than 100,000
light years,
386
00:24:31,137 --> 00:24:33,304
but not always
it was so big,
387
00:24:35,575 --> 00:24:37,775
when you think about things
so vast
388
00:24:37,777 --> 00:24:39,810
so gigantic and ancient
like galaxies,
389
00:24:39,812 --> 00:24:41,278
you're kind of tempted to think
390
00:24:41,280 --> 00:24:42,847
that they are
very stable objects
391
00:24:42,849 --> 00:24:44,815
that they don't change
a lot over time,
392
00:24:44,817 --> 00:24:46,617
but now we know
that our own galaxy
393
00:24:46,619 --> 00:24:48,552
is the product of many
smaller galaxies
394
00:24:48,554 --> 00:24:50,354
who came together over time,
395
00:24:50,356 --> 00:24:53,057
and there are other galaxies
still colliding with us,
396
00:24:56,028 --> 00:24:58,295
braid: we see galaxies
Eating each other all the time,
397
00:24:58,297 --> 00:25:00,998
they collide,
What if a galaxy is too big
398
00:25:01,000 --> 00:25:02,867
and a galaxy is very small,
399
00:25:02,869 --> 00:25:06,136
the little galaxy falls
the big one breaks apart,
400
00:25:06,138 --> 00:25:10,241
and becomes a part
of that larger galaxy,
401
00:25:10,243 --> 00:25:12,576
:
the milky way may be dying,
402
00:25:12,578 --> 00:25:16,046
but it's still a monster
foraging through the universe
403
00:25:16,048 --> 00:25:18,415
swallowing minor
entire galaxies,
404
00:25:21,988 --> 00:25:24,054
Consume your stars,
405
00:25:24,056 --> 00:25:28,125
but it also has a taste
for its star-building gas,
406
00:25:29,996 --> 00:25:33,330
and it doesn't have
collide with other galaxies
407
00:25:33,332 --> 00:25:36,667
to feed on them,
408
00:25:36,669 --> 00:25:39,470
Now, the lifeblood of a galaxy
is hydrogen gas,
409
00:25:39,472 --> 00:25:41,739
this is what really
creates new stars,
410
00:25:41,741 --> 00:25:44,708
just like a dwarf galaxy
passes through the milky way,
411
00:25:44,710 --> 00:25:47,912
tremendously massive
milky way halo,
412
00:25:47,914 --> 00:25:51,282
all this gas, you can take it out
dwarf galaxy material,
413
00:25:51,284 --> 00:25:53,350
adding it to the milky way,
414
00:25:53,352 --> 00:25:55,586
so, in this way,
the milky way sinks
415
00:25:55,588 --> 00:25:58,622
the vital blood
from other galaxies,
416
00:25:58,624 --> 00:26:01,191
in some sense you could say
is a vampire
417
00:26:01,193 --> 00:26:03,994
because a vampire sucks the life
of other things
418
00:26:03,996 --> 00:26:05,429
so you can stay young,
419
00:26:09,368 --> 00:26:16,674
:
in its 13 billion year life,
our galaxy of vampires had fun,
420
00:26:16,676 --> 00:26:19,944
consuming the vital blood
of their galactic victims,
421
00:26:19,946 --> 00:26:22,780
The milky way grew fat,
422
00:26:25,217 --> 00:26:28,352
but it could be so monstrous
feeding frenzy be a factor
423
00:26:28,354 --> 00:26:30,187
in the death of the Milky Way?
424
00:26:33,092 --> 00:26:34,992
Once again, crucial evidence
425
00:26:34,994 --> 00:26:39,597
comes from
sloan digital sky survey,
426
00:26:39,599 --> 00:26:42,666
your telescope maps
the stars in our galaxy,
427
00:26:42,668 --> 00:26:46,470
but also maps
the galaxies in our universe,
428
00:26:48,941 --> 00:26:54,445
looking at distant galaxies
It's like looking back in time,
429
00:26:54,447 --> 00:26:56,847
because further away
they are,
430
00:26:56,849 --> 00:26:59,617
more your light
takes to reach us,
431
00:27:02,488 --> 00:27:07,424
we see the most distant
galaxies not as they are now,
432
00:27:07,426 --> 00:27:12,096
but as they were -
Billions of years ago,
433
00:27:12,098 --> 00:27:13,530
so when you look
in these galaxies,
434
00:27:13,532 --> 00:27:15,799
you're seeing them as they were
when they were very young,
435
00:27:15,801 --> 00:27:18,802
and you're seeing these galaxies
as they are more recently,
436
00:27:18,804 --> 00:27:21,171
so you can really look
in evolution -
437
00:27:21,173 --> 00:27:25,075
how galaxies change over time
as the universe ages,
438
00:27:27,213 --> 00:27:28,779
:
while studying the data,
439
00:27:28,781 --> 00:27:31,782
scientists do
a dramatic discovery,
440
00:27:31,784 --> 00:27:36,353
they find spiral galaxies,
just like the milky way,
441
00:27:36,355 --> 00:27:40,090
dying throughout the universe,
442
00:27:40,092 --> 00:27:42,926
and what connects them
is your mass,
443
00:27:44,964 --> 00:27:46,530
there seems to be
a higher weight limit
444
00:27:46,532 --> 00:27:49,366
for the sizes of
spiral galaxies,
445
00:27:49,368 --> 00:27:51,835
up to a trillion times
the mass of the sun,
446
00:27:51,837 --> 00:27:54,738
we see spiral galaxies
that continue to form stars,
447
00:27:54,740 --> 00:27:56,707
but once they pass
this threshold,
448
00:27:56,709 --> 00:27:59,109
galaxies tend to die
and run out of stars,
449
00:28:01,280 --> 00:28:03,380
narrator:while devouring
the star-building gas
450
00:28:03,382 --> 00:28:05,582
of smaller galaxies,
451
00:28:05,584 --> 00:28:08,686
the milky way
may have grown up obese,
452
00:28:08,688 --> 00:28:12,690
and now you might be suffocating
to death at his own dinner,
453
00:28:12,692 --> 00:28:14,958
but how?
454
00:28:14,960 --> 00:28:17,661
once a spiral galaxy
is big enough,
455
00:28:17,663 --> 00:28:20,264
there will be one
incredible gravitational force
456
00:28:20,266 --> 00:28:22,666
so, any gas that pulls
for yourself
457
00:28:22,668 --> 00:28:26,236
will come in
at an incredibly high speed,
458
00:28:26,238 --> 00:28:28,439
this gas will be
overheated,
459
00:28:32,344 --> 00:28:34,978
Narrator: the superheated gas
moves so quickly
460
00:28:34,980 --> 00:28:39,083
which is prevented
of falling into the milky way,
461
00:28:39,085 --> 00:28:44,254
gas is very energetic for our
the galaxy's gravity to pull you,
462
00:28:44,256 --> 00:28:48,459
instead it remains in the halo
around the milky way,
463
00:28:48,461 --> 00:28:53,197
and the food of our galaxy
the supply is blocked,
464
00:28:53,199 --> 00:28:57,634
eventually, our galaxy
will die of hunger,
465
00:28:57,636 --> 00:28:59,536
this will only happen
if the milky way
466
00:28:59,538 --> 00:29:02,973
It's about building stars
weight limit,
467
00:29:02,975 --> 00:29:07,511
but how exactly
do you weigh a galaxy?
468
00:29:07,513 --> 00:29:09,980
a basic way
we can weigh a galaxy
469
00:29:09,982 --> 00:29:12,683
is to measure how fast
the stars are moving inside her,
470
00:29:12,685 --> 00:29:15,619
So, the faster the stars orbit
around the center of the galaxy,
471
00:29:15,621 --> 00:29:18,489
the more massive the galaxy,
472
00:29:18,491 --> 00:29:22,793
narrator:
this weighing method
The milky way depends on gravity,
473
00:29:22,795 --> 00:29:26,063
fast moving stars need
more gravity to keep them
474
00:29:26,065 --> 00:29:27,397
in their orbits,
475
00:29:27,399 --> 00:29:32,269
and more severity means
more galactic mass,
476
00:29:32,271 --> 00:29:36,373
when scientists use it
information to perform the math,
477
00:29:36,375 --> 00:29:39,910
The horrible truth is revealed,
478
00:29:39,912 --> 00:29:42,613
thaller:we passed
a critical level,
479
00:29:42,615 --> 00:29:46,183
the milky way is very big
for your own health,
480
00:29:46,185 --> 00:29:49,019
and we entered
the beginning of the end,
481
00:29:49,021 --> 00:29:52,222
braid:
We're running out of gas,
and I mean it, literally,
482
00:29:52,224 --> 00:29:54,091
gas clouds form stars,
483
00:29:54,093 --> 00:29:57,528
and as they form stars,
they are exhausted,
484
00:29:57,530 --> 00:29:59,763
and so our gas tank
is getting closer and closer
485
00:29:59,765 --> 00:30:02,266
to empty every day,
486
00:30:06,038 --> 00:30:09,072
narrator:
the investigation into
the death of the milky way
487
00:30:09,074 --> 00:30:10,440
is closed,
488
00:30:12,645 --> 00:30:14,011
the verdict?
489
00:30:14,013 --> 00:30:17,815
the greedy dairy way
you are killing yourself,
490
00:30:20,452 --> 00:30:24,454
over millions of years,
star formation is stopped,
491
00:30:24,456 --> 00:30:26,356
and the galaxy dies,
492
00:30:28,994 --> 00:30:34,131
but could
the galaxy be resurrected?
493
00:30:34,133 --> 00:30:35,999
You seem to be talking
a very sad story,
494
00:30:36,001 --> 00:30:38,202
we are talking about the disappearance
of the milky way galaxy -
495
00:30:38,204 --> 00:30:39,970
the end of star formation -
496
00:30:39,972 --> 00:30:41,805
but maybe it's just
a little too early
497
00:30:41,807 --> 00:30:43,574
to write death
announcement yet,
498
00:30:43,576 --> 00:30:46,076
hope could be
just on the horizon,
499
00:30:48,914 --> 00:30:52,149
in space and astrophysics,
really everything is possible,
500
00:30:52,151 --> 00:30:58,355
♪♪
501
00:30:59,758 --> 00:31:08,165
♪
in space and astrophysics,
really everything is possible,
502
00:31:08,167 --> 00:31:12,936
narrator:
the shocking case of our
Galaxy's death has been resolved,
503
00:31:12,938 --> 00:31:15,272
there was no killer,
504
00:31:15,274 --> 00:31:18,942
It turns out, the milky way
is feeding itself to death,
505
00:31:23,182 --> 00:31:26,650
But is this really the end?
506
00:31:26,652 --> 00:31:29,620
could salvation
be in our way?
507
00:31:31,523 --> 00:31:33,390
even if star formation is
turning off
508
00:31:33,392 --> 00:31:34,758
in the milky way now,
509
00:31:34,760 --> 00:31:36,560
we know it's in
a collision course
510
00:31:36,562 --> 00:31:38,528
with the Andromeda galaxy,
511
00:31:38,530 --> 00:31:39,696
they are moving towards each other
512
00:31:39,698 --> 00:31:44,001
in hundreds of thousands
of miles per hour,
513
00:31:44,003 --> 00:31:45,502
a collision occurs
like something
514
00:31:45,504 --> 00:31:47,037
this is always destructive,
515
00:31:47,039 --> 00:31:49,039
but this is not
necessarily the case,
516
00:31:51,977 --> 00:31:53,176
narrator:
the collision of the Milky Way
517
00:31:53,178 --> 00:31:57,114
with our giant
Andromeda galactic neighbor
518
00:31:57,116 --> 00:32:00,284
it won't happen
for another 4 billion years,
519
00:32:02,621 --> 00:32:06,256
Until then, star formation
in both galaxies
520
00:32:06,258 --> 00:32:07,958
will stop completely,
521
00:32:10,729 --> 00:32:14,731
but a giant encounter
could change all this,
522
00:32:18,003 --> 00:32:19,469
Sutter:
like an isolated galaxy,
523
00:32:19,471 --> 00:32:22,873
the milky way is already
in its deceleration phase,
524
00:32:22,875 --> 00:32:26,543
not producing as many
new stars like it used to,
525
00:32:26,545 --> 00:32:30,714
but is a way to generate
a new round of star formation,
526
00:32:30,716 --> 00:32:34,418
and this is through
a galactic merger event,
527
00:32:34,420 --> 00:32:36,386
braid:when andromeda
is close enough,
528
00:32:36,388 --> 00:32:38,488
mutual gravity
between the two galaxies
529
00:32:38,490 --> 00:32:42,793
will begin to stretch them,
pulling them like taffy,
530
00:32:42,795 --> 00:32:45,729
the stars will be removed
these long looped ribbons,
531
00:32:45,731 --> 00:32:46,863
and then the galaxies
532
00:32:46,865 --> 00:32:50,033
will physically pass
each other,
533
00:32:50,035 --> 00:32:53,804
Eventually, the two galaxies
you will join again
534
00:32:53,806 --> 00:32:56,440
and join
a gigantic galaxy,
535
00:32:56,442 --> 00:32:58,375
and at that point,
all these gas clouds
536
00:32:58,377 --> 00:33:01,545
will flash in the star formation,
537
00:33:06,251 --> 00:33:10,787
Narrator: As the galaxies merge,
they will be reborn,
538
00:33:10,789 --> 00:33:13,757
two dying spiral galaxies
539
00:33:13,759 --> 00:33:18,028
become a single living
elliptical galaxy
540
00:33:18,030 --> 00:33:22,032
called milkomeda,
541
00:33:22,034 --> 00:33:24,634
imagine that you are living
the distant future of the galaxy
542
00:33:24,636 --> 00:33:26,236
and you see the night sky
543
00:33:26,238 --> 00:33:28,805
while the milky way
and andromeda are colliding,
544
00:33:28,807 --> 00:33:31,108
will seem
a very different place,
545
00:33:31,110 --> 00:33:33,343
instead of one
Through the night sky,
546
00:33:33,345 --> 00:33:36,079
you can have two
how the two disks come together,
547
00:33:36,081 --> 00:33:37,748
it will be a miraculous vision,
548
00:33:37,750 --> 00:33:40,584
but very, very different
place of what we have today,
549
00:33:43,889 --> 00:33:49,059
narrator:
our sky will light up for the
first time in billions of years,
550
00:33:49,061 --> 00:33:52,496
the star formation will light up
across the galaxy,
551
00:33:54,833 --> 00:33:57,734
but it's too early
celebrate?
552
00:34:01,473 --> 00:34:03,840
this new round of star formation
553
00:34:03,842 --> 00:34:07,677
during the merger
of our two galaxies -
554
00:34:07,679 --> 00:34:10,047
while it's really cool
for a little while,
555
00:34:10,049 --> 00:34:14,785
Once it's over, this kind of
send the new galaxy
556
00:34:14,787 --> 00:34:16,186
in a death spiral,
557
00:34:16,188 --> 00:34:18,955
when new stars are born
in this new galaxy,
558
00:34:18,957 --> 00:34:23,260
many of them are going to
be hot, big, blue stars,
559
00:34:23,262 --> 00:34:26,463
eventually those young, hot
the stars will start to die,
560
00:34:26,465 --> 00:34:28,565
and when they do,
they will explode
561
00:34:28,567 --> 00:34:30,567
violently like supernovae,
562
00:34:30,569 --> 00:34:36,039
♪♪
563
00:34:36,041 --> 00:34:38,041
and these supernovae
will start
564
00:34:38,043 --> 00:34:40,577
expelling gas from the galaxy,
565
00:34:44,249 --> 00:34:45,782
ox:
All the gas is gone,
566
00:34:45,784 --> 00:34:48,085
there are no more things
to form stars,
567
00:34:48,087 --> 00:34:49,853
And that's what kills a galaxy,
568
00:34:53,625 --> 00:34:55,926
narrator: it's going to take a while
hundreds of millions of years
569
00:34:55,928 --> 00:35:00,530
for milkomeda
to run out of star-building gas,
570
00:35:00,532 --> 00:35:04,835
and then our new elliptical
Galaxy will starve,
571
00:35:06,638 --> 00:35:09,239
but the final blow
is yet to come,
572
00:35:11,677 --> 00:35:13,910
another question to consider
that's what happens
573
00:35:13,912 --> 00:35:15,946
for the two supermassives
black holes
574
00:35:15,948 --> 00:35:18,648
in the cores of
the two galaxies,
575
00:35:18,650 --> 00:35:21,184
Well, initially, they're going
to orbit,
576
00:35:21,186 --> 00:35:25,755
stirring up a lot of turbulence,
and they will combine,
577
00:35:25,757 --> 00:35:28,692
and why there is
a lot of new gas, hot and fresh,
578
00:35:28,694 --> 00:35:31,862
our new galaxy is
it will be a quasar,
579
00:35:31,864 --> 00:35:34,397
and this quasar is going
to increase the heat,
580
00:35:34,399 --> 00:35:36,032
will appear
the turbulence,
581
00:35:36,034 --> 00:35:39,269
and that means star formation
will be turned off,
582
00:35:41,540 --> 00:35:45,142
narrator:
The combined power of
supermassive black holes
583
00:35:45,144 --> 00:35:49,146
help create a quasar
that tears the galaxy apart,
584
00:35:52,251 --> 00:35:55,452
release fierce
radiation beams
585
00:35:55,454 --> 00:35:59,022
that exploded through the milkomeda
star-forming gas,
586
00:36:02,361 --> 00:36:04,261
was only reborn,
587
00:36:04,263 --> 00:36:08,832
but our newly enlarged galaxy
is dying once again,
588
00:36:11,537 --> 00:36:16,706
large galaxies, such as milkomeda,
It seems doomed from the start,
589
00:36:16,708 --> 00:36:20,810
its size creates many
problems for star formation,
590
00:36:23,315 --> 00:36:26,583
or, so we think,
591
00:36:26,585 --> 00:36:28,919
more galaxies we see,
the more we realize
592
00:36:28,921 --> 00:36:30,987
there's a lot out there
we didn't find out,
593
00:36:30,989 --> 00:36:32,756
and there's a new class
of galaxies
594
00:36:32,758 --> 00:36:35,158
only recently identified,
595
00:36:35,160 --> 00:36:39,763
these galaxies are more than 10
times the mass of the milky way,
596
00:36:39,765 --> 00:36:43,867
and, intriguingly,
they are still forming stars,
597
00:36:43,869 --> 00:36:45,602
apparently
we lost something,
598
00:36:45,604 --> 00:36:50,106
♪♪
599
00:36:51,510 --> 00:37:01,284
♪
apparently
we lost something,
600
00:37:01,286 --> 00:37:04,221
♪♪
601
00:37:04,223 --> 00:37:09,459
narrator:
4 billion years from now,
The milky way is nothing more,
602
00:37:09,461 --> 00:37:12,596
After colliding with the Andromeda,
is reborn
603
00:37:12,598 --> 00:37:16,499
like a giant elliptical galaxy
called milkomeda,
604
00:37:18,437 --> 00:37:22,872
scientists thought galaxies
This great one was doomed,
605
00:37:22,874 --> 00:37:25,942
But is hope on the horizon?
606
00:37:28,413 --> 00:37:31,982
the sloan digital sky survey
spent a decade
607
00:37:31,984 --> 00:37:36,553
studying
more than a million galaxies,
608
00:37:36,555 --> 00:37:40,957
discovered a rare
but a huge kind of galaxy -
609
00:37:40,959 --> 00:37:42,726
a super spiral,
610
00:37:45,631 --> 00:37:48,565
these super-spiral galaxies
They are spiral galaxies
611
00:37:48,567 --> 00:37:50,133
which are incredibly super,
612
00:37:50,135 --> 00:37:53,903
and by "super", I mean
they are four times the size,
613
00:37:53,905 --> 00:37:55,605
10 times the mass,
614
00:37:55,607 --> 00:37:57,274
and they are strange
because they exceed
615
00:37:57,276 --> 00:38:00,277
the supposed weight limit
For spiral galaxies,
616
00:38:00,279 --> 00:38:03,280
so they shouldn't have
new stars, but yes,
617
00:38:03,282 --> 00:38:05,615
They are very healthy galaxies,
618
00:38:05,617 --> 00:38:11,221
♪♪
619
00:38:11,223 --> 00:38:15,125
narrator:scientists discovered
only 53 super spirals,
620
00:38:18,230 --> 00:38:22,332
super spiral galaxy show
that in rare situations,
621
00:38:22,334 --> 00:38:26,903
massive galaxies continue
to produce new stars,
622
00:38:30,776 --> 00:38:34,311
So this is a lifeline
for milkomeda?
623
00:38:37,149 --> 00:38:39,182
thaller:when we think about
two columns of galaxies,
624
00:38:39,184 --> 00:38:40,817
many of our computer models
suggest
625
00:38:40,819 --> 00:38:42,419
that they really
mess with each other,
626
00:38:42,421 --> 00:38:44,120
Things get very chaotic,
627
00:38:44,122 --> 00:38:47,957
but over time, they could resolve
Back to a spiral shape?
628
00:38:47,959 --> 00:38:50,827
and, in fact, this may be
What happens to super spirals,
629
00:38:50,829 --> 00:38:53,396
one of the clues is that many
super spiral galaxies
630
00:38:53,398 --> 00:38:54,931
has dual cores,
631
00:38:54,933 --> 00:38:57,400
instead of just being
a supermassive black hole,
632
00:38:57,402 --> 00:39:01,237
there actually exist
two orbiting each other,
633
00:39:01,239 --> 00:39:03,840
the fact that we see spiral
galaxies with two cores
634
00:39:03,842 --> 00:39:05,875
made it possible
that you could have a collision
635
00:39:05,877 --> 00:39:08,411
and still survive
like a spiral galaxy,
636
00:39:08,413 --> 00:39:11,381
so maybe there is hope that even
the milky way will be a spiral
637
00:39:11,383 --> 00:39:13,416
once it collides
with andromeda,
638
00:39:17,622 --> 00:39:21,424
Narrator: imagine the scene -
6 billion years in the future,
639
00:39:23,628 --> 00:39:26,229
milkomeda drias
across the universe,
640
00:39:28,200 --> 00:39:32,235
,not like an elliptical galaxy,
but like a super spiral,
641
00:39:34,806 --> 00:39:39,476
this shape means the galaxy
it is much more stable,
642
00:39:39,478 --> 00:39:41,511
the harmful heat
and turbulence
643
00:39:41,513 --> 00:39:45,014
generated by milkomeda
supermassive black holes
644
00:39:45,016 --> 00:39:51,054
can't stop star-building gas
exit in the spiral arms,
645
00:39:51,056 --> 00:39:56,893
far from dying,
our galaxy continues -
646
00:39:56,895 --> 00:40:00,597
bigger than ever,
647
00:40:00,599 --> 00:40:03,867
but this is not
the end of the story,
648
00:40:03,869 --> 00:40:06,970
tens of billions
of the years from now,
649
00:40:06,972 --> 00:40:10,940
could the galaxy
continues to grow?
650
00:40:10,942 --> 00:40:13,176
our local group of galaxies -
651
00:40:13,178 --> 00:40:15,712
Milky Way, Andromeda,
triangle -
652
00:40:15,714 --> 00:40:19,449
and then a collection
of dwarf satellite galaxies -
653
00:40:19,451 --> 00:40:22,519
is gravitationally
United,
654
00:40:22,521 --> 00:40:25,121
and eventually,
we are all together
655
00:40:25,123 --> 00:40:27,323
into a single massive object,
656
00:40:29,060 --> 00:40:30,527
Bullock: what does that mean?
657
00:40:30,529 --> 00:40:32,962
This means we can be part of
one of the largest structures
658
00:40:32,964 --> 00:40:35,165
in the universe,
659
00:40:35,167 --> 00:40:37,434
narrator:during
is billions of years of life,
660
00:40:37,436 --> 00:40:42,038
the milky way changes
beyond recognition,
661
00:40:42,040 --> 00:40:45,375
suffers countless collisions,
662
00:40:45,377 --> 00:40:49,546
Parties in many smaller galaxies,
663
00:40:49,548 --> 00:40:52,615
and gives birth
to countless stars,
664
00:40:54,820 --> 00:40:56,886
thaller: we talk about
the life cycle of galaxies -
665
00:40:56,888 --> 00:41:00,089
how they were born, how they live
healthy lives making new stars,
666
00:41:00,091 --> 00:41:02,192
and eventually
how they die,
667
00:41:02,194 --> 00:41:04,360
actually it's not
as depressing as that,
668
00:41:04,362 --> 00:41:06,463
All in
the universe changes,
669
00:41:08,533 --> 00:41:13,837
narrator:
galaxies like ours are in
a constant stream of flow,
670
00:41:13,839 --> 00:41:16,639
So when it comes to
the Milky Way,
671
00:41:16,641 --> 00:41:19,275
Death really isn't the end,
672
00:41:21,179 --> 00:41:22,745
oluseyi:
what we see in our universe
673
00:41:22,747 --> 00:41:26,516
is that there is always
a process of birth and rebirth,
674
00:41:26,518 --> 00:41:28,084
so the future
of the milky way
675
00:41:28,086 --> 00:41:30,386
is this going to happen
keep doing what you do,
676
00:41:33,024 --> 00:41:34,724
ox:
Galaxies are always changing,
677
00:41:34,726 --> 00:41:36,159
10 billion years ago,
the milky way
678
00:41:36,161 --> 00:41:37,994
it was nothing like
what is today,
679
00:41:37,996 --> 00:41:39,996
and certainly,
10 billion years in the future,
680
00:41:39,998 --> 00:41:41,831
it will be very
different place,
681
00:41:44,402 --> 00:41:46,769
braid:
Look, I live in this galaxy,
682
00:41:46,771 --> 00:41:49,372
I hope you can find a way
to rejuvenate
683
00:41:49,374 --> 00:41:51,508
through collisions
or some other process
684
00:41:51,510 --> 00:41:53,243
because it gives me some hope
685
00:41:53,245 --> 00:41:56,112
that will continue
for a long, long time,