TedTest

From the Ted Talk by Sajan Saini: What is the universe expanding into?

Unscramble the Blue Letters

The universe began its cosmic life in a big bang nearly feuroetn billion years ago, and has been expanding ever since. But what is it expanding into? That's a complicated question. Here's why: Einstein's equations of general relativity describe space and time as a kind of inter-connected fabric for the universe. This means that what we know of as space and time exist only as part of the universe and not beyond it. Now, when everyday objects expand, they move out into more space. But if there is no such thing as space to expand into, what does expanding even mean? In 1929 Edwin Hubble's aonrtomsy observations gave us a definitive aenwsr. His survey of the night sky found all faawray gaelaixs recede, or move away, from the Earth. Moreover, the further the galaxy, the fasetr it recedes. How can we interpret this? Consider a loaf of riisan bared rising in the oven. The batter rises by the same amount in between each and every raisin. If we think of rnsaiis as a stand-in for galaxies, and batter as the sacpe between them, we can imagine that the stretching or expansion of igirtaletacnc space will make the galaxies recede from each other, and for any galaxy, its faraway nihgrbeos will recede a larger distance than the neabry ones in the same amount of time. Sure enough, the equations of general relativity predict a cosmic tug-of-war between gravity and expansion. It's only in the dark void between galaxies where expansion wins out, and space stretches. So there's our answer. The universe is expanding unto itself. That said, cosmologists are pushing the lmtiis of mathematical mldeos to speculate on what, if anything, exists beyond our spacetime. These aren't wild guesses, but hypotheses that tackle kikns in the scientific theory of the Big Bang. The Big Bang predicts matter to be distributed elveny across the universe, as a sparse gas —but then, how did galaxies and stars come to be? The inflationary model describes a brief era of incredibly rapid epxnosain that relates quantum fluctuations in the egrney of the early universe, to the formation of clumps of gas that eventually led to galaxies. If we accept this paradigm, it may also imply our universe rsenepters one region in a greater cosmic reality that undergoes endless, eternal inflation. We know nothing of this speculative inflating reality, save for the mathematical prediction that its endless expansion may be dviern by an unstable quantum energy state. In many local regions, however, the energy may settle by random chance into a stable state, stopping inflation and forming bubble universes. Each bubble universe —ours being one of them —would be described by its own Big Bang and laws of physics. Our universe would be part of a greater multiverse, in which the fantastic rate of eternal iaoinftln makes it impossible for us to enetcuonr a neighbor universe. The Big Bang also predicts that in the early, hot universe, our fundamental fcroes may unify into one super-force. Mathematical string theories sgguest descriptions of this unification, in addition to a fuenantmadl structure for sub-atomic quarks and electrons. In these peoosrpd models, vibrating strings are the building blocks of the universe. Competing models for strings have now been consolidated into a unified drpcoiseitn, and suggest these structures may icrnaett with massive, higher dnnomsiaeil scefarus caleld branes. Our universe may be contained within one such banre, floating in an uwnnokn higher dimensional place, playfully named “the bulk,” or hyperspace. Other branes—containing other types of universes—may co-exist in hraescppye, and neighboring branes may even sarhe certain fundamental forces like gravity. Both eternal inflation and branes describe a multiverse, but while universes in eternal inflation are isolated, brane urveniess could bump into each other. An echo of such a ciiooslln may appear in the comsic microwave background —a soup of radiation throughout our universe, that’s a relic from an eraly Big Bang era. So far, though, we’ve found no such cosmic echo. Some suspect these differing multiverse hpesyheots may elvlenauty coalesce into a common description, or be replaced by something else. As it sntads now, they’re speculative elrtxoioanps of mehmaaatictl models. While these models are inspired and guided by many scientific experiments, there are very few ovijcebte experiments to directly test them, yet. Until the next Edwin Hubble comes along, scientists will likely be left to agure about the elegance of their competing models… and continue to dream about what, if anything, lies beyond our universe.

Open Cloze

The universe began its cosmic life in a big bang nearly ________ billion years ago, and has been expanding ever since. But what is it expanding into? That's a complicated question. Here's why: Einstein's equations of general relativity describe space and time as a kind of inter-connected fabric for the universe. This means that what we know of as space and time exist only as part of the universe and not beyond it. Now, when everyday objects expand, they move out into more space. But if there is no such thing as space to expand into, what does expanding even mean? In 1929 Edwin Hubble's _________ observations gave us a definitive ______. His survey of the night sky found all _______ ________ recede, or move away, from the Earth. Moreover, the further the galaxy, the ______ it recedes. How can we interpret this? Consider a loaf of ______ _____ rising in the oven. The batter rises by the same amount in between each and every raisin. If we think of _______ as a stand-in for galaxies, and batter as the _____ between them, we can imagine that the stretching or expansion of _____________ space will make the galaxies recede from each other, and for any galaxy, its faraway _________ will recede a larger distance than the ______ ones in the same amount of time. Sure enough, the equations of general relativity predict a cosmic tug-of-war between gravity and expansion. It's only in the dark void between galaxies where expansion wins out, and space stretches. So there's our answer. The universe is expanding unto itself. That said, cosmologists are pushing the ______ of mathematical ______ to speculate on what, if anything, exists beyond our spacetime. These aren't wild guesses, but hypotheses that tackle _____ in the scientific theory of the Big Bang. The Big Bang predicts matter to be distributed ______ across the universe, as a sparse gas —but then, how did galaxies and stars come to be? The inflationary model describes a brief era of incredibly rapid _________ that relates quantum fluctuations in the ______ of the early universe, to the formation of clumps of gas that eventually led to galaxies. If we accept this paradigm, it may also imply our universe __________ one region in a greater cosmic reality that undergoes endless, eternal inflation. We know nothing of this speculative inflating reality, save for the mathematical prediction that its endless expansion may be ______ by an unstable quantum energy state. In many local regions, however, the energy may settle by random chance into a stable state, stopping inflation and forming bubble universes. Each bubble universe —ours being one of them —would be described by its own Big Bang and laws of physics. Our universe would be part of a greater multiverse, in which the fantastic rate of eternal _________ makes it impossible for us to _________ a neighbor universe. The Big Bang also predicts that in the early, hot universe, our fundamental ______ may unify into one super-force. Mathematical string theories _______ descriptions of this unification, in addition to a ___________ structure for sub-atomic quarks and electrons. In these ________ models, vibrating strings are the building blocks of the universe. Competing models for strings have now been consolidated into a unified ___________, and suggest these structures may ________ with massive, higher ___________ ________ ______ branes. Our universe may be contained within one such _____, floating in an _______ higher dimensional place, playfully named “the bulk,” or hyperspace. Other branes—containing other types of universes—may co-exist in __________, and neighboring branes may even _____ certain fundamental forces like gravity. Both eternal inflation and branes describe a multiverse, but while universes in eternal inflation are isolated, brane _________ could bump into each other. An echo of such a _________ may appear in the ______ microwave background —a soup of radiation throughout our universe, that’s a relic from an _____ Big Bang era. So far, though, we’ve found no such cosmic echo. Some suspect these differing multiverse __________ may __________ coalesce into a common description, or be replaced by something else. As it ______ now, they’re speculative ____________ of ____________ models. While these models are inspired and guided by many scientific experiments, there are very few _________ experiments to directly test them, yet. Until the next Edwin Hubble comes along, scientists will likely be left to _____ about the elegance of their competing models… and continue to dream about what, if anything, lies beyond our universe.

Solution

dimensional
space
bread
forces
expansion
stands
intergalactic
inflation
interact
share
answer
surfaces
cosmic
represents
argue
hypotheses
called
limits
neighbors
galaxies
encounter
energy
mathematical
unknown
faraway
faster
astronomy
nearby
raisins
suggest
fundamental
explorations
brane
description
raisin
collision
early
fourteen
eventually
universes
proposed
models
objective
hyperspace
driven
evenly
kinks

Original Text

The universe began its cosmic life in a big bang nearly fourteen billion years ago, and has been expanding ever since. But what is it expanding into? That's a complicated question. Here's why: Einstein's equations of general relativity describe space and time as a kind of inter-connected fabric for the universe. This means that what we know of as space and time exist only as part of the universe and not beyond it. Now, when everyday objects expand, they move out into more space. But if there is no such thing as space to expand into, what does expanding even mean? In 1929 Edwin Hubble's astronomy observations gave us a definitive answer. His survey of the night sky found all faraway galaxies recede, or move away, from the Earth. Moreover, the further the galaxy, the faster it recedes. How can we interpret this? Consider a loaf of raisin bread rising in the oven. The batter rises by the same amount in between each and every raisin. If we think of raisins as a stand-in for galaxies, and batter as the space between them, we can imagine that the stretching or expansion of intergalactic space will make the galaxies recede from each other, and for any galaxy, its faraway neighbors will recede a larger distance than the nearby ones in the same amount of time. Sure enough, the equations of general relativity predict a cosmic tug-of-war between gravity and expansion. It's only in the dark void between galaxies where expansion wins out, and space stretches. So there's our answer. The universe is expanding unto itself. That said, cosmologists are pushing the limits of mathematical models to speculate on what, if anything, exists beyond our spacetime. These aren't wild guesses, but hypotheses that tackle kinks in the scientific theory of the Big Bang. The Big Bang predicts matter to be distributed evenly across the universe, as a sparse gas —but then, how did galaxies and stars come to be? The inflationary model describes a brief era of incredibly rapid expansion that relates quantum fluctuations in the energy of the early universe, to the formation of clumps of gas that eventually led to galaxies. If we accept this paradigm, it may also imply our universe represents one region in a greater cosmic reality that undergoes endless, eternal inflation. We know nothing of this speculative inflating reality, save for the mathematical prediction that its endless expansion may be driven by an unstable quantum energy state. In many local regions, however, the energy may settle by random chance into a stable state, stopping inflation and forming bubble universes. Each bubble universe —ours being one of them —would be described by its own Big Bang and laws of physics. Our universe would be part of a greater multiverse, in which the fantastic rate of eternal inflation makes it impossible for us to encounter a neighbor universe. The Big Bang also predicts that in the early, hot universe, our fundamental forces may unify into one super-force. Mathematical string theories suggest descriptions of this unification, in addition to a fundamental structure for sub-atomic quarks and electrons. In these proposed models, vibrating strings are the building blocks of the universe. Competing models for strings have now been consolidated into a unified description, and suggest these structures may interact with massive, higher dimensional surfaces called branes. Our universe may be contained within one such brane, floating in an unknown higher dimensional place, playfully named “the bulk,” or hyperspace. Other branes—containing other types of universes—may co-exist in hyperspace, and neighboring branes may even share certain fundamental forces like gravity. Both eternal inflation and branes describe a multiverse, but while universes in eternal inflation are isolated, brane universes could bump into each other. An echo of such a collision may appear in the cosmic microwave background —a soup of radiation throughout our universe, that’s a relic from an early Big Bang era. So far, though, we’ve found no such cosmic echo. Some suspect these differing multiverse hypotheses may eventually coalesce into a common description, or be replaced by something else. As it stands now, they’re speculative explorations of mathematical models. While these models are inspired and guided by many scientific experiments, there are very few objective experiments to directly test them, yet. Until the next Edwin Hubble comes along, scientists will likely be left to argue about the elegance of their competing models… and continue to dream about what, if anything, lies beyond our universe.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
big bang	6
eternal inflation	4
general relativity	2
mathematical models	2
fundamental forces	2
higher dimensional	2

Important Words

accept
addition
amount
answer
argue
astronomy
background
bang
batter
began
big
billion
blocks
brane
branes
bread
bubble
building
bulk
bump
called
chance
clumps
coalesce
collision
common
competing
complicated
consolidated
contained
continue
cosmic
cosmologists
dark
definitive
describe
describes
description
descriptions
differing
dimensional
distance
distributed
dream
driven
early
earth
echo
edwin
electrons
elegance
encounter
endless
energy
equations
era
eternal
evenly
eventually
everyday
exist
exists
expand
expanding
expansion
experiments
explorations
fabric
fantastic
faraway
faster
floating
fluctuations
forces
formation
forming
fourteen
fundamental
galaxies
galaxy
gas
gave
general
gravity
greater
guesses
guided
higher
hot
hubble
hyperspace
hypotheses
imagine
imply
impossible
incredibly
inflating
inflation
inflationary
inspired
interact
intergalactic
interpret
isolated
kind
kinks
larger
laws
led
left
lies
life
limits
loaf
local
massive
mathematical
matter
means
microwave
model
models
move
multiverse
named
nearby
neighbor
neighboring
neighbors
night
objective
objects
observations
oven
paradigm
part
physics
place
playfully
predict
prediction
predicts
proposed
pushing
quantum
quarks
question
radiation
raisin
raisins
random
rapid
rate
reality
recede
recedes
region
regions
relates
relativity
relic
replaced
represents
rises
rising
save
scientific
scientists
settle
share
sky
soup
space
spacetime
sparse
speculate
speculative
stable
stands
stars
state
stopping
stretches
stretching
string
strings
structure
structures
suggest
surfaces
survey
suspect
tackle
test
theories
theory
time
types
undergoes
unification
unified
unify
universe
universes
unknown
unstable
vibrating
void
wild
wins
years