Could human civilization spread across the whole galaxy? - Roey Tzezana
-
0:07 - 0:12Could human civilization eventually spread
across the whole Milky Way galaxy? -
0:12 - 0:15Could we move beyond
our small blue planet -
0:15 - 0:20to establish colonies in the multitude
of star systems out there? -
0:20 - 0:22This question's a pretty daunting one.
-
0:22 - 0:26There are around 300 billion stars
in the galaxy, -
0:26 - 0:29which is about 160,000 light-years across.
-
0:29 - 0:34So far we've sent a single spacecraft
outside our solar system, -
0:34 - 0:39trudging along at 0.006% of
the speed of light. -
0:39 - 0:43At that rate, it would take over
2.5 billion years -
0:43 - 0:46just to get from one end of the galaxy
to the other. -
0:46 - 0:48And then there's the question
of human survival. -
0:48 - 0:51The gulf between stars is simply enormous.
-
0:51 - 0:54We couldn't live sustainably
on most planets, -
0:54 - 0:58and we require a lot of resources
to stay alive. -
0:58 - 1:02And yet, decades ago, scholars found
that it's theoretically possible -
1:02 - 1:05to not just spread human civilization
across the galaxy, -
1:05 - 1:08but to do so quite quickly,
-
1:08 - 1:11without breaking any known
laws of physics. -
1:11 - 1:15Their idea is based on the work
of a mathematician named John von Neumann, -
1:15 - 1:19who designed on paper machines
that could self-replicate -
1:19 - 1:22and create new generations of themselves.
-
1:22 - 1:26These would later come to be known
as von Neumann machines. -
1:26 - 1:28In the context of space exploration,
-
1:28 - 1:30von Neumann machines could be
built on Earth -
1:30 - 1:32and launched into space.
-
1:32 - 1:36There, the self-sufficient machines
would land on distant planets. -
1:36 - 1:40They would then mine the available
resources and harvest energy, -
1:40 - 1:43build replicas of themselves,
-
1:43 - 1:45launch those to the nearest planets,
-
1:45 - 1:46and continue the cycle.
-
1:46 - 1:49The result is the creation
of millions of probes -
1:49 - 1:54spreading outwards into the universe
like a drop of ink in a fishbowl. -
1:54 - 1:58Scholars crunched the numbers and found
that a single von Neumann machine -
1:58 - 2:00traveling at 5% of the speed of light
-
2:00 - 2:06should be able to replicate throughout
our galaxy in 4 million years or less. -
2:06 - 2:08That may sound like a long time,
-
2:08 - 2:12but when you consider that our universe
is 14 billion years old, -
2:12 - 2:14on a cosmic scale, it's incredibly fast -
-
2:14 - 2:20the equivalent of about 2.5 hours
in an entire year. -
2:20 - 2:23Creating von Neumann machines
would require a few technologies -
2:23 - 2:25we don't have yet,
-
2:25 - 2:27including advanced
artificial intelligence, -
2:27 - 2:29miniaturization,
-
2:29 - 2:31and better propulsion systems.
-
2:31 - 2:34If we wanted to use them to spread actual
humans throughout the galaxy, -
2:34 - 2:37we would need
yet another technological leap - -
2:37 - 2:42the ability to artificially
grow biological organisms and bodies -
2:42 - 2:45using raw elements
and genetic information. -
2:45 - 2:47Regardless, if in the last billion years
-
2:47 - 2:50an alien civilization
created such a machine -
2:50 - 2:53and set it multiplying its way toward us,
-
2:53 - 2:56our galaxy would be
swarming with them by now. -
2:56 - 2:59So then where are all these machines?
-
2:59 - 3:01Some astronomers, like Carl Sagan,
-
3:01 - 3:06say that intelligent aliens wouldn't
build self-replicating machines at all. -
3:06 - 3:08They might hurtle out of control,
-
3:08 - 3:12scavenging planets to their cores
in order to keep replicating. -
3:12 - 3:14Others take the machines absence as proof
-
3:14 - 3:17that intelligent alien civilizations
don't exist, -
3:17 - 3:22or that they go extinct before they can
develop the necessary technologies. -
3:22 - 3:25But all this hasn't stopped people from
imagining what it would be like -
3:25 - 3:27if they were out there.
-
3:27 - 3:29Science fiction author David Brin
-
3:29 - 3:33writes about a universe in which
many different von Neumann machines exist -
3:33 - 3:35and proliferate simultaneously.
-
3:35 - 3:38Some are designed
to greet young civilizations, -
3:38 - 3:42others to locate and destroy them
before they become a threat. -
3:42 - 3:45In fact, in Brin's story "Lungfish,"
-
3:45 - 3:50some von Neumann machines are keeping
a close watch over the Earth right now, -
3:50 - 3:53waiting for us to reach a certain level
of sophistication -
3:53 - 3:56before they make their move.
-
3:56 - 3:59For now, all we have is curiosity
and theory. -
3:59 - 4:01But the next time
you look at the night sky, -
4:01 - 4:04consider that billions of
self-replicating machines -
4:04 - 4:10could be advancing between stars
in our galaxy right now. -
4:10 - 4:13If they exist, one of them will eventually
land on Earth, -
4:13 - 4:17or maybe, just maybe,
they're already here.
- Title:
- Could human civilization spread across the whole galaxy? - Roey Tzezana
- Speaker:
- Roey Tzezana
- Description:
-
View full lesson: http://ed.ted.com/lessons/could-human-civilization-spread-across-the-whole-galaxy-roey-tzezana
Could human civilization eventually spread across the whole Milky Way galaxy? Could we move beyond our small, blue planet to establish colonies in the multitude of star systems out there? These questions are pretty daunting, but their (theoretical) answers were actually put forth decades ago. Roey Tzezana describes the conceptual von Neumann machine.
Lesson by Roey Tzezana, animation by Eoin Duffy.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:34
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Jessica Ruby edited English subtitles for Could human civilization spread across the whole galaxy? |