TedTest

From the Ted Talk by Roey Tzezana: Could human civilization spread across the whole galaxy?

Unscramble the Blue Letters

Could human civilization eventually spread across the whole Milky Way galaxy? Could we move beyond our slmal blue planet to establish colonies in the multitude of star systems out there? This question's a ptrety daunting one. There are around 300 billion stars in the glaaxy, which is about 160,000 light-years across. So far we've sent a single spacecraft outside our solar system, trugdnig along at 0.006% of the speed of light. At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other. And then there's the question of hmaun survival. The gulf between stars is simply enormous. We couldn't live sustainably on most pleants, and we require a lot of resources to stay alive. And yet, decades ago, scholars found that it's theoretically possible to not just saperd human civilization across the galaxy, but to do so quite quickly, without breaking any known laws of physics. Their idea is besad on the work of a mmhtaiacteain named John von Neumann, who designed on pepar minhaces that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines. In the context of space exploration, von naunemn machines could be built on Earth and launched into space. There, the self-sufficient machines would land on distant planets. They would then mine the available resources and harvest eegrny, build replicas of themselves, launch those to the nesaert planets, and cnituone the cycle. The result is the creation of millions of probes sdipaerng odaruwts into the universe like a drop of ink in a fishbowl. Scholars crunched the numbers and found that a single von Neumann machine traveling at 5% of the seped of light should be able to replicate throughout our galaxy in 4 million years or less. That may sound like a long time, but when you consider that our universe is 14 billion years old, on a cosmic scale, it's incredibly fast - the equivalent of about 2.5 hours in an entire year. Creating von Neumann machines would require a few technologies we don't have yet, including advanced artificial intelligence, miniaturization, and better pislropuon systems. If we wanted to use them to spread auactl hmunas throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological organisms and bodies using raw elements and genetic information. Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some arrnsmooets, like Carl saagn, say that iglentnielt ailnes wouldn't build self-replicating machines at all. They might hurtle out of control, scavenging planets to their cores in oderr to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don't exist, or that they go extinct before they can develop the necessary tgnehecloois. But all this hasn't stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines exsit and proliferate simultaneously. Some are designed to greet young civilizations, others to locate and destroy them before they become a threat. In fact, in Brin's story "Lungfish," some von Neumann machines are keeping a close watch over the Earth right now, wiiantg for us to reach a certain leevl of soiptiahtiocsn before they make their move. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will eaenvlutly land on ertah, or maybe, just maybe, they're already here.

Open Cloze

Could human civilization eventually spread across the whole Milky Way galaxy? Could we move beyond our _____ blue planet to establish colonies in the multitude of star systems out there? This question's a ______ daunting one. There are around 300 billion stars in the ______, which is about 160,000 light-years across. So far we've sent a single spacecraft outside our solar system, ________ along at 0.006% of the speed of light. At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other. And then there's the question of _____ survival. The gulf between stars is simply enormous. We couldn't live sustainably on most _______, and we require a lot of resources to stay alive. And yet, decades ago, scholars found that it's theoretically possible to not just ______ human civilization across the galaxy, but to do so quite quickly, without breaking any known laws of physics. Their idea is _____ on the work of a _____________ named John von Neumann, who designed on _____ ________ that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines. In the context of space exploration, von _______ machines could be built on Earth and launched into space. There, the self-sufficient machines would land on distant planets. They would then mine the available resources and harvest ______, build replicas of themselves, launch those to the _______ planets, and ________ the cycle. The result is the creation of millions of probes _________ ________ into the universe like a drop of ink in a fishbowl. Scholars crunched the numbers and found that a single von Neumann machine traveling at 5% of the _____ of light should be able to replicate throughout our galaxy in 4 million years or less. That may sound like a long time, but when you consider that our universe is 14 billion years old, on a cosmic scale, it's incredibly fast - the equivalent of about 2.5 hours in an entire year. Creating von Neumann machines would require a few technologies we don't have yet, including advanced artificial intelligence, miniaturization, and better __________ systems. If we wanted to use them to spread ______ ______ throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological organisms and bodies using raw elements and genetic information. Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some ___________, like Carl _____, say that ___________ ______ wouldn't build self-replicating machines at all. They might hurtle out of control, scavenging planets to their cores in _____ to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don't exist, or that they go extinct before they can develop the necessary ____________. But all this hasn't stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines _____ and proliferate simultaneously. Some are designed to greet young civilizations, others to locate and destroy them before they become a threat. In fact, in Brin's story "Lungfish," some von Neumann machines are keeping a close watch over the Earth right now, _______ for us to reach a certain _____ of ______________ before they make their move. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will __________ land on _____, or maybe, just maybe, they're already here.

Solution

machines
speed
continue
nearest
pretty
intelligent
exist
aliens
humans
actual
astronomers
sagan
order
planets
paper
energy
sophistication
galaxy
mathematician
propulsion
waiting
human
spreading
trudging
level
earth
technologies
eventually
based
small
neumann
outwards
spread

Original Text

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? This question's a pretty daunting one. There are around 300 billion stars in the galaxy, which is about 160,000 light-years across. So far we've sent a single spacecraft outside our solar system, trudging along at 0.006% of the speed of light. At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other. And then there's the question of human survival. The gulf between stars is simply enormous. We couldn't live sustainably on most planets, and we require a lot of resources to stay alive. And yet, decades ago, scholars found that it's theoretically possible to not just spread human civilization across the galaxy, but to do so quite quickly, without breaking any known laws of physics. Their idea is based on the work of a mathematician named John von Neumann, who designed on paper machines that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines. In the context of space exploration, von Neumann machines could be built on Earth and launched into space. There, the self-sufficient machines would land on distant planets. They would then mine the available resources and harvest energy, build replicas of themselves, launch those to the nearest planets, and continue the cycle. The result is the creation of millions of probes spreading outwards into the universe like a drop of ink in a fishbowl. Scholars crunched the numbers and found that a single von Neumann machine traveling at 5% of the speed of light should be able to replicate throughout our galaxy in 4 million years or less. That may sound like a long time, but when you consider that our universe is 14 billion years old, on a cosmic scale, it's incredibly fast - the equivalent of about 2.5 hours in an entire year. Creating von Neumann machines would require a few technologies we don't have yet, including advanced artificial intelligence, miniaturization, and better propulsion systems. If we wanted to use them to spread actual humans throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological organisms and bodies using raw elements and genetic information. Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some astronomers, like Carl Sagan, say that intelligent aliens wouldn't build self-replicating machines at all. They might hurtle out of control, scavenging planets to their cores in order to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don't exist, or that they go extinct before they can develop the necessary technologies. But all this hasn't stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines exist and proliferate simultaneously. Some are designed to greet young civilizations, others to locate and destroy them before they become a threat. In fact, in Brin's story "Lungfish," some von Neumann machines are keeping a close watch over the Earth right now, waiting for us to reach a certain level of sophistication before they make their move. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will eventually land on Earth, or maybe, just maybe, they're already here.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
von neumann	6
neumann machines	5
billion years	3
human civilization	2

ngrams of length 3

collocation	frequency
von neumann machines	5

Important Words

ability
absence
actual
advanced
advancing
alien
aliens
alive
artificial
artificially
astronomers
author
based
billion
billions
biological
blue
bodies
breaking
brin
build
built
carl
civilization
civilizations
close
colonies
context
continue
control
cores
cosmic
create
created
creating
creation
crunched
curiosity
cycle
daunting
david
decades
designed
destroy
develop
distant
drop
earth
elements
energy
enormous
entire
equivalent
establish
eventually
exist
exploration
extinct
fact
fast
fiction
fishbowl
galaxy
generations
genetic
greet
grow
gulf
harvest
hours
human
humans
hurtle
idea
imagining
including
incredibly
information
ink
intelligence
intelligent
john
keeping
land
launch
launched
laws
leap
level
light
live
locate
long
lot
machine
machines
mathematician
milky
million
millions
miniaturization
move
multiplying
multitude
named
nearest
neumann
night
numbers
order
organisms
outwards
paper
people
physics
planet
planets
pretty
probes
proliferate
proof
propulsion
question
quickly
rate
raw
reach
replicas
replicate
replicating
require
resources
result
sagan
scale
scavenging
scholars
science
set
simply
simultaneously
single
sky
small
solar
sophistication
sound
space
spacecraft
speed
spread
spreading
star
stars
stay
stopped
story
survival
sustainably
swarming
system
systems
technological
technologies
theoretically
theory
threat
time
traveling
trudging
universe
von
waiting
wanted
watch
work
writes
year
years
young