TedTest

From the Ted Talk by Renée Hlozek: The death of the universe

Unscramble the Blue Letters

Looking up at the nihgt sky, we are amazed by how it seems to go on forever. But what will the sky look like billions of years from now? A particular type of scientist, called a cosmologist, spedns her time thinking about that very question. The end of the universe is intimately linked to what the universe contains. Over 100 years ago, Einstein dveoepeld the Theory of General raivltitey, formed of equations that help us understand the relationship between what a universe is made of and its shape. It turns out that the universe could be curved like a ball or shpree. We call this poilsivtey curved or closed. Or it could be shaped like a saddle. We call this neegtivlay cuervd or open. Or it could be flat. And that sahpe deenritmes how the universe will live and die. We now know that the universe is very close to flat. However, the components of the universe can still affect its eventual fate. We can predict how the universe will change with time if we mrauese the amounts or energy densities of the various components in the universe tdoay. So, what is the universe made of? The universe contains all the things that we can see, like stars, gas, and planets. We call these things ordinary or baryonic matter. Even though we see them all around us, the total energy density of these components is actually very small, around 5% of the taotl energy of the universe. So, now let's talk about what the other 95% is. Just under 27% of the rest of the energy density of the universe is made up of what we call dark matter. Dark matter is only very weakly interacting with lhgit, which maens it doesn't shine or reflect light in the way that stars and patlnes do, but, in every other way, it bveahes like ordinary metatr — it attracts things gravitationally. In fact, the only way we can detect this dark matter is through this gravitational interaction, how things orbit around it and how it bends light as it curves the space around it. We have yet to discover a dark matter particle, but scientists all over the world are searching for this elusive particle or particles and the effects of dark matter on the universe. But this still doesn't add up to 100%. The remaining 68% of the energy density of the universe is made up of dark energy, which is even more mysterious than dark matter. This dark energy doesn't behave like any other substance we know at all and acts more like anti-gravity fcore. We say that it has a gravitational pressure, which ordinary matter and dark matter do not. Instead of pulling the universe together, as we would expect gravity to do, the unvisere appears to be expanding apart at an ever-increasing rate. The leading idea for dark energy is that it is a cosmological constant. That means it has the strange property that it expands as the volume of space increases to keep its energy density constant. So, as the universe epdnaxs as it is doing right now, there will be more and more dark engery. Dark matter and baonriyc matter, on the other hand, don't exanpd with the universe and become more diluted. Because of this propetry of the cosmological constant, the future universe will be more and more dominated by dark energy, becoming colder and colder and epadixnng faster and faster. eaeltunlvy, the universe will run out of gas to form sarts, and the stars themselves will run out of fuel and burn out, leaving the universe with only black holes in it. Given enough time, even these black heols will evaporate, leaving a universe that is ceoleltmpy cold and empty. That is what we call the heat death of the universe. While it might sound depressing living in a universe that will end its lifetime cold and devoid of life, the end fate of our universe actually has a beautiful symmetry to its hot, fiery beginning. We call the accelerating end state of the universe a de Sitter phase, named after the Dutch mathematician Willem de Sitter. However, we also believe that the universe had another phase of de stetir expansion in the earliest times of its life. We call this early period inflation, where, shortly after the Big Bang, the universe expanded extremely fast for a brief period. So, the universe will end in much the same state as it began, accelerating. We live at an extraordinary time in the life of the universe where we can sartt to understand the universe's journey and view a history that plays itself out on the sky for all of us to see.

Open Cloze

Looking up at the _____ sky, we are amazed by how it seems to go on forever. But what will the sky look like billions of years from now? A particular type of scientist, called a cosmologist, ______ her time thinking about that very question. The end of the universe is intimately linked to what the universe contains. Over 100 years ago, Einstein _________ the Theory of General __________, formed of equations that help us understand the relationship between what a universe is made of and its shape. It turns out that the universe could be curved like a ball or ______. We call this __________ curved or closed. Or it could be shaped like a saddle. We call this __________ ______ or open. Or it could be flat. And that _____ __________ how the universe will live and die. We now know that the universe is very close to flat. However, the components of the universe can still affect its eventual fate. We can predict how the universe will change with time if we _______ the amounts or energy densities of the various components in the universe _____. So, what is the universe made of? The universe contains all the things that we can see, like stars, gas, and planets. We call these things ordinary or baryonic matter. Even though we see them all around us, the total energy density of these components is actually very small, around 5% of the _____ energy of the universe. So, now let's talk about what the other 95% is. Just under 27% of the rest of the energy density of the universe is made up of what we call dark matter. Dark matter is only very weakly interacting with _____, which _____ it doesn't shine or reflect light in the way that stars and _______ do, but, in every other way, it _______ like ordinary ______ — it attracts things gravitationally. In fact, the only way we can detect this dark matter is through this gravitational interaction, how things orbit around it and how it bends light as it curves the space around it. We have yet to discover a dark matter particle, but scientists all over the world are searching for this elusive particle or particles and the effects of dark matter on the universe. But this still doesn't add up to 100%. The remaining 68% of the energy density of the universe is made up of dark energy, which is even more mysterious than dark matter. This dark energy doesn't behave like any other substance we know at all and acts more like anti-gravity _____. We say that it has a gravitational pressure, which ordinary matter and dark matter do not. Instead of pulling the universe together, as we would expect gravity to do, the ________ appears to be expanding apart at an ever-increasing rate. The leading idea for dark energy is that it is a cosmological constant. That means it has the strange property that it expands as the volume of space increases to keep its energy density constant. So, as the universe _______ as it is doing right now, there will be more and more dark ______. Dark matter and ________ matter, on the other hand, don't ______ with the universe and become more diluted. Because of this ________ of the cosmological constant, the future universe will be more and more dominated by dark energy, becoming colder and colder and _________ faster and faster. __________, the universe will run out of gas to form _____, and the stars themselves will run out of fuel and burn out, leaving the universe with only black holes in it. Given enough time, even these black _____ will evaporate, leaving a universe that is __________ cold and empty. That is what we call the heat death of the universe. While it might sound depressing living in a universe that will end its lifetime cold and devoid of life, the end fate of our universe actually has a beautiful symmetry to its hot, fiery beginning. We call the accelerating end state of the universe a de Sitter phase, named after the Dutch mathematician Willem de Sitter. However, we also believe that the universe had another phase of de ______ expansion in the earliest times of its life. We call this early period inflation, where, shortly after the Big Bang, the universe expanded extremely fast for a brief period. So, the universe will end in much the same state as it began, accelerating. We live at an extraordinary time in the life of the universe where we can _____ to understand the universe's journey and view a history that plays itself out on the sky for all of us to see.

Solution

stars
expands
spends
light
positively
start
relativity
sitter
shape
force
measure
planets
determines
expand
universe
night
developed
expanding
baryonic
total
energy
today
eventually
holes
behaves
sphere
negatively
curved
property
matter
completely
means

Original Text

Looking up at the night sky, we are amazed by how it seems to go on forever. But what will the sky look like billions of years from now? A particular type of scientist, called a cosmologist, spends her time thinking about that very question. The end of the universe is intimately linked to what the universe contains. Over 100 years ago, Einstein developed the Theory of General Relativity, formed of equations that help us understand the relationship between what a universe is made of and its shape. It turns out that the universe could be curved like a ball or sphere. We call this positively curved or closed. Or it could be shaped like a saddle. We call this negatively curved or open. Or it could be flat. And that shape determines how the universe will live and die. We now know that the universe is very close to flat. However, the components of the universe can still affect its eventual fate. We can predict how the universe will change with time if we measure the amounts or energy densities of the various components in the universe today. So, what is the universe made of? The universe contains all the things that we can see, like stars, gas, and planets. We call these things ordinary or baryonic matter. Even though we see them all around us, the total energy density of these components is actually very small, around 5% of the total energy of the universe. So, now let's talk about what the other 95% is. Just under 27% of the rest of the energy density of the universe is made up of what we call dark matter. Dark matter is only very weakly interacting with light, which means it doesn't shine or reflect light in the way that stars and planets do, but, in every other way, it behaves like ordinary matter — it attracts things gravitationally. In fact, the only way we can detect this dark matter is through this gravitational interaction, how things orbit around it and how it bends light as it curves the space around it. We have yet to discover a dark matter particle, but scientists all over the world are searching for this elusive particle or particles and the effects of dark matter on the universe. But this still doesn't add up to 100%. The remaining 68% of the energy density of the universe is made up of dark energy, which is even more mysterious than dark matter. This dark energy doesn't behave like any other substance we know at all and acts more like anti-gravity force. We say that it has a gravitational pressure, which ordinary matter and dark matter do not. Instead of pulling the universe together, as we would expect gravity to do, the universe appears to be expanding apart at an ever-increasing rate. The leading idea for dark energy is that it is a cosmological constant. That means it has the strange property that it expands as the volume of space increases to keep its energy density constant. So, as the universe expands as it is doing right now, there will be more and more dark energy. Dark matter and baryonic matter, on the other hand, don't expand with the universe and become more diluted. Because of this property of the cosmological constant, the future universe will be more and more dominated by dark energy, becoming colder and colder and expanding faster and faster. Eventually, the universe will run out of gas to form stars, and the stars themselves will run out of fuel and burn out, leaving the universe with only black holes in it. Given enough time, even these black holes will evaporate, leaving a universe that is completely cold and empty. That is what we call the heat death of the universe. While it might sound depressing living in a universe that will end its lifetime cold and devoid of life, the end fate of our universe actually has a beautiful symmetry to its hot, fiery beginning. We call the accelerating end state of the universe a de Sitter phase, named after the Dutch mathematician Willem de Sitter. However, we also believe that the universe had another phase of de Sitter expansion in the earliest times of its life. We call this early period inflation, where, shortly after the Big Bang, the universe expanded extremely fast for a brief period. So, the universe will end in much the same state as it began, accelerating. We live at an extraordinary time in the life of the universe where we can start to understand the universe's journey and view a history that plays itself out on the sky for all of us to see.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
dark matter	8
energy density	4
dark energy	3
de sitter	3
total energy	2
ordinary matter	2
black holes	2

Important Words

accelerating
acts
add
affect
amazed
amounts
appears
attracts
ball
bang
baryonic
beautiful
began
beginning
behave
behaves
bends
big
billions
black
burn
call
called
change
close
closed
cold
colder
completely
components
constant
cosmological
cosmologist
curved
curves
dark
de
death
densities
density
depressing
detect
determines
developed
devoid
die
diluted
discover
dominated
dutch
earliest
early
effects
einstein
elusive
empty
energy
equations
evaporate
eventual
eventually
expand
expanded
expanding
expands
expansion
expect
extraordinary
extremely
fact
fast
faster
fate
fiery
flat
force
form
formed
fuel
future
gas
general
gravitational
gravitationally
gravity
hand
heat
history
holes
hot
idea
increases
inflation
interacting
interaction
intimately
journey
leading
leaving
life
lifetime
light
linked
live
living
mathematician
matter
means
measure
mysterious
named
negatively
night
open
orbit
ordinary
particle
particles
period
phase
planets
plays
positively
predict
pressure
property
pulling
question
rate
reflect
relationship
relativity
remaining
rest
run
saddle
scientist
scientists
searching
shape
shaped
shine
shortly
sitter
sky
small
sound
space
spends
sphere
stars
start
state
strange
substance
symmetry
talk
theory
thinking
time
times
today
total
turns
type
understand
universe
view
volume
weakly
willem
world
years