3341:, about 5 gigaparsecs or 16 billion light-years, will never reach us, although we can still see the light that these galaxies emitted in the past. Because of the high rate of expansion, it is also possible for a distance between two objects to be greater than the value calculated by multiplying the speed of light by the age of the universe. These details are a frequent source of confusion among amateurs and even professional physicists. Due to the non-intuitive nature of the subject and what has been described by some as "careless" choices of wording, certain descriptions of the metric expansion of space and the misconceptions to which such descriptions can lead are an ongoing subject of discussion within the fields of education and communication of scientific concepts.
3266:
objects to grow steadily or to disintegrate; unless they are very weakly bound, they will simply settle into an equilibrium state that is slightly (undetectably) larger than it would otherwise have been. As the universe expands and the matter in it thins, the gravitational attraction decreases (since it is proportional to the density), while the cosmological repulsion increases. Thus, the ultimate fate of the ΛCDM universe is a near-vacuum expanding at an ever-increasing rate under the influence of the cosmological constant. However, gravitationally bound objects like the Milky Way do not expand, and the
Andromeda Galaxy is moving fast enough towards us that it will still merge with the Milky Way in around 3 billion years.
5115:
3151:
expand, since an expansion of an infinite expanse can happen without changing the infinite extent of the expanse. All that is certain is that the manifold of space in which we live simply has the property that the distances between objects are getting larger as time goes on. This only implies the simple observational consequences associated with the metric expansion explored below. No "outside" or embedding in hyperspace is required for an expansion to occur. The visualizations often seen of the universe growing as a bubble into nothingness are misleading in that respect. There is no reason to believe there is anything "outside" the expanding universe into which the universe expands.
3038:, its time in transit (about 13 billion years) is not related to the distance traveled in any simple way, since the universe expands as the light beam traverses space and time. The distance traveled is thus inherently ambiguous because of the changing scale of the universe. Nevertheless, there are two distances that appear to be physically meaningful: the distance between Earth and the quasar when the light was emitted, and the distance between them in the present era (taking a slice of the cone along the dimension defined as the spatial dimension). The former distance is about 4 billion light-years, much smaller than
2888:
2877:
1123:
3369:, even though observations suggest that the real universe is spatially flat, but this inconsistency can be eliminated by making the balloon very large so that it is locally flat within the limits of observation. This analogy is potentially confusing since it could wrongly suggest that the Big Bang took place at the center of the balloon. In fact points off the surface of the balloon have no meaning, even if they were occupied by the balloon at an earlier time or will be occupied later.
2333:
572:
2513:
49:
2757:
5151:
2658:
5163:
5127:
5089:
584:
3192:
2699:
5139:
3007:. The red line is the path of a light beam emitted by the quasar about 13 billion years ago and reaching Earth at the present day. The orange line shows the present-day distance between the quasar and Earth, about 28 billion light-years, which is a larger distance than the age of the universe multiplied by the speed of light,
3222:, the gravitational interactions have changed the inertial patterns of objects such that there is no cosmological expansion taking place. Beyond the Local Group, the inertial expansion is measurable, though systematic gravitational effects imply that larger and larger parts of space will eventually fall out of the "
3349:
The expansion of the universe is often illustrated with conceptual models where an expanding object is taken to represent expanding space. These models can be misleading to the extent that they give the false impression that expanding space must carry objects with it. In reality, the expansion of the
3146:
of the early universe also implies that the "total universe" is much larger than the observable universe. Thus any edges or exotic geometries or topologies would not be directly observable, since light has not reached scales on which such aspects of the universe, if they exist, are still allowed. For
1796:
If the dark energy that is inferred to dominate the universe today is a cosmological constant, then the particle horizon converges to a finite value in the infinite future. This implies that the amount of the universe that we will ever be able to observe is limited. Many systems exist whose light can
3357:
model" one imagines an ant (idealized as pointlike) crawling at a constant speed on a perfectly elastic rope that is constantly stretching. If we stretch the rope in accordance with the ΛCDM scale factor and think of the ant's speed as the speed of light, then this analogy is conceptually accurate –
3199:
In addition to slowing the overall expansion, gravity causes local clumping of matter into stars and galaxies. Once objects are formed and bound by gravity, they "drop out" of the expansion and do not subsequently expand under the influence of the cosmological metric, there being no force compelling
2630:
In principle, the cosmic expansion history can also be measured by studying how redshifts, distances, fluxes, angular positions, and angular sizes of astronomical objects change over the course of the time that they are being observed. These effects are too small to have yet been detected. However,
790:
was the first person to find observational evidence for expansion, in 1924. According to Ian Steer of the NASA/IPAC Extragalactic
Database of Galaxy Distances, "Lundmark's extragalactic distance estimates were far more accurate than Hubble's, consistent with an expansion rate (Hubble constant) that
3316:
or evolution in time become important. These situations are described by general relativity, which allows the separation between two distant objects to increase faster than the speed of light, although the definition of "distance" here is somewhat different from that used in an inertial frame. The
3150:
Regardless of the overall shape of the universe, the question of what the universe is expanding into is one that does not require an answer, according to the theories that describe the expansion; the way we define space in our universe in no way requires additional exterior space into which it can
3265:
density has the effect of adding a repulsive force between objects that is proportional (not inversely proportional) to distance. Unlike inertia it actively "pulls" on objects that have clumped together under the influence of gravity, and even on individual atoms. However, this does not cause the
3372:
In the "raisin bread model", one imagines a loaf of raisin bread expanding in an oven. The loaf (space) expands as a whole, but the raisins (gravitationally bound objects) do not expand; they merely move farther away from each other. This analogy has the disadvantage of wrongly implying that the
3053:
from Earth when it was first emitted; the metric distance to Earth increased with cosmological time for the first few billion years of its travel time, also indicating that the expansion of space between Earth and the quasar at the early time was faster than the speed of light. None of this
2503:
Around 3 billion years ago, at a time of about 11 billion years, dark energy is believed to have begun to dominate the energy density of the universe. This transition came about because dark energy does not dilute as the universe expands, instead maintaining a constant energy density.
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at intervals of one billion light-years in the present era (less in the past and more in the future). The circular curling of the surface is an artifact of the embedding with no physical significance and is done for illustrative purposes; a flat universe does not curl back onto itself. (A
2524:
The most direct way to measure the expansion rate is to independently measure the recession velocities and the distances of distant objects, such as galaxies. The ratio between these quantities gives the Hubble rate, in accordance with Hubble's law. Typically, the distance is measured using a
1138:), which sent the contents of the universe flying apart. The mutual gravitational attraction of the matter and radiation within the universe gradually slows this expansion over time, but expansion nevertheless continues due to momentum left over from the initial impulse. Also, certain exotic
3361:
In the "rubber sheet model", one replaces the rope with a flat two-dimensional rubber sheet that expands uniformly in all directions. The addition of a second spatial dimension allows for the possibility of showing local perturbations of the spatial geometry by local curvature in the sheet.
2340:
to the present day, with the inflationary epoch represented as the dramatic expansion seen on the left. This visualization shows only a section of the universe; the empty space outside the diagram should not be taken to represent empty space outside the universe (which does not necessarily
2439:
came to dominate the energy density of the universe. This transition happened at a time of about 50 thousand years after the Big Bang. During the matter-dominated epoch, cosmic expansion also decelerated, with the scale factor growing as the 2/3 power of the time
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cosmological model. Two of the dimensions of space are omitted, leaving one dimension of space (the dimension that grows as the cone gets larger) and one of time (the dimension that proceeds "up" the cone's surface). The narrow circular end of the diagram corresponds to a
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Supernovae are observable at such great distances that the light travel time therefrom can approach the age of the universe. Consequently, they can be used to measure not only the present-day expansion rate but also the expansion history. In work that was awarded the 2011
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Riess, Adam G.; Macri, Lucas M.; Hoffmann, Samantha L.; Scolnic, Dan; Casertano, Stefano; Filippenko, Alexei V.; Tucker, Brad E.; Reid, Mark J.; Jones, David O.; Silverman, Jeffrey M.; Chornock, Ryan; Challis, Peter; Yuan, Wenlong; Brown, Peter J.; Foley, Ryan J. (2016).
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The universe is a four-dimensional spacetime, but within a universe that obeys the cosmological principle, there is a natural choice of three-dimensional spatial surface. These are the surfaces on which observers who are stationary in comoving coordinates agree on the
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of galaxies. Such future events are predicted by knowing the precise way the Hubble Flow is changing as well as the masses of the objects to which we are being gravitationally pulled. Currently, the Local Group is being gravitationally pulled towards either the
3154:
Even if the overall spatial extent is infinite and thus the universe cannot get any "larger", we still say that space is expanding because, locally, the characteristic distance between objects is increasing. As an infinite space grows, it remains infinite.
692:. Contrary to common misconception, it is equally valid to adopt a description in which space does not expand and objects simply move apart while under the influence of their mutual gravity. Although cosmic expansion is often framed as a consequence of
1228:. If the universe continues to expand forever, the scale factor will approach infinity in the future. It is also possible in principle for the universe to stop expanding and begin to contract, which corresponds to the scale factor decreasing in time.
3187:
The expansion of space is sometimes described as a force that acts to push objects apart. Though this is an accurate description of the effect of the cosmological constant, it is not an accurate picture of the phenomenon of expansion in general.
3046:. In other words, if space were not expanding today, it would take 28 billion years for light to travel between Earth and the quasar, while if the expansion had stopped at the earlier time, it would have taken only 4 billion years.
1843:. This can be understood as a self-sorting effect. A particle that is moving in some direction gradually overtakes the Hubble flow of cosmic expansion in that direction, asymptotically approaching material with the same velocity as its own.
4346:
1958:
The contents of the universe dilute as it expands. The number of particles within a comoving volume remains fixed (on average), while the volume expands. For nonrelativistic matter, this implies that the energy density drops as
715:, the universe suddenly expanded, and its volume increased by a factor of at least 10 (an expansion of distance by a factor of at least 10 in each of the three dimensions). This would be equivalent to expanding an object 1
1784:
An expanding universe typically has a finite age. Light, and other particles, can have propagated only a finite distance. The comoving distance that such particles can have covered over the age of the universe is known as the
3026:; in the diagram, this means, according to the convention of constructing spacetime diagrams, that light beams always make an angle of 45° with the local grid lines. It does not follow, however, that light travels a distance
2954:
has four dimensions; it is not flat according to
Einstein's general theory of relativity. Einstein's theory postulates that "matter and energy curve spacetime, and there is enough matter and energy to provide for curvature."
1812:
much larger than the Hubble horizon are not dynamical, because gravitational influences do not have time to propagate across them, while perturbations much smaller than the Hubble horizon are straightforwardly governed by
3090:, and the time through which various events take place. The expansion of space is in reference to this 3D manifold only; that is, the description involves no structures such as extra dimensions or an exterior universe.
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as a splaying outward of the spacetime, a feature that eventually dominates in this model. The purple grid lines mark cosmological time at intervals of one billion years from the Big Bang. The cyan grid lines mark
1834:
is its velocity with respect to the comoving coordinate grid, i.e., with respect to the average expansion-associated motion of the surrounding material. It is a measure of how a particle's motion deviates from the
1223:
is smaller in the past and larger in the future. Extrapolating back in time with certain cosmological models will yield a moment when the scale factor was zero; our current understanding of cosmology sets
3129:
universe", where if traveling far enough in one direction would allow one to simply end up back in the same place like going all the way around the surface of a balloon (or a planet like the Earth), is
1769:
spatial surfaces is affected by gravity. Current observations are consistent with these spatial surfaces being geometrically flat (so that, for example, the angles of a triangle add up to 180 degrees).
2939:
hold in the present universe in 3D space. It is, however, possible that the geometry of past 3D space could have been highly curved. The curvature of space is often modeled using a non-zero
739:, or 62 trillion miles). Cosmic expansion subsequently decelerated to much slower rates, until around 9.8 billion years after the Big Bang (4 billion years ago) it began to gradually
1265:
4350:
3203:
There is no difference between the inertial expansion of the universe and the inertial separation of nearby objects in a vacuum; the former is simply a large-scale extrapolation of the latter.
4287:
3049:
The light took much longer than 4 billion years to reach us though it was emitted from only 4 billion light-years away. In fact, the light emitted towards Earth was actually moving
3086:
into which our respective positions are embedded, while 'universe' refers to everything that exists, including the matter and energy in space, the extra dimensions that may be wrapped up in
2403:
grew exponentially in time. In order to solve the horizon and flatness problems, inflation must have lasted long enough that the scale factor grew by at least a factor of e (about 10).
2197:
684:(which governs the size and geometry of spacetime). Within this framework, the separation of objects over time is associated with the expansion of space itself. However, this is not a
1065:
3142:
limit our ability to distinguish between simple and more complicated proposals. The universe could be infinite in extent or it could be finite; but the evidence that leads to the
2056:
1993:
1585:
2537:. Meanwhile, the recession speed is measured through the redshift. Hubble used this approach for his original measurement of the expansion rate, by measuring the brightness of
1638:
751:
in the simplest gravitational models, as a way to explain this late-time acceleration. According to the simplest extrapolation of the currently favored cosmological model, the
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2411:
The history of the universe after inflation but before a time of about 1 second is largely unknown. However, the universe is known to have been dominated by ultrarelativistic
1538:
1948:
1912:
1854:. While the cosmological redshift is often explained as the stretching of photon wavelengths due to "expansion of space", it is more naturally viewed as a consequence of the
1690:
3365:
In the "balloon model" the flat sheet is replaced by a spherical balloon that is inflated from an initial size of zero (representing the Big Bang). A balloon has positive
1012:
983:
4425:
Davis, Tamara M.; Lineweaver, Charles H. (2004). "Expanding
Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe".
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expansion, so it does not mean that the universe expands "into" anything or that space exists "outside" it. To any observer in the universe, it appears that all but
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at about 1 second. During radiation domination, cosmic expansion decelerated, with the scale factor growing proportionally with the square root of the time.
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of the expanding universe, with no other motion, then it remains stationary in comoving coordinates. The comoving coordinates are the spatial coordinates in the
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2013:
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1221:
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means that rapidly receding distant observers' clocks are slowed, so that spatial surfaces must bend "into the future" over long distances. However, within
1692:. Negative-pressure fluids, like dark energy, are not experimentally confirmed, but the existence of dark energy is inferred from astronomical observations.
1177:, which is proportional to the average separation between objects, such as galaxies. The scale factor is a function of time and is conventionally set to be
3242:
A consequence of metric expansion being due to inertial motion is that a uniform local "explosion" of matter into a vacuum can be locally described by the
956:, in which objects recede from each observer with velocities proportional to their positions with respect to that observer. That is, recession velocities
2982:
of 700 million years after the Big Bang, while the wide end is a cosmological time of 18 billion years, where one can see the beginning of the
3337:. Visibility of these objects depends on the exact expansion history of the universe. Light that is emitted today from galaxies beyond the more-distant
3082:', sometimes used interchangeably, have distinct meanings in this context. Here 'space' is a mathematical concept that stands for the three-dimensional
4823:
4168:
Chen, Hsin-Yu; Fishbach, Maya; Holz, Daniel E. (17 October 2018). "A two per cent Hubble constant measurement from standard sirens within five years".
2481:). Also, gravitational structure formation is most efficient when nonrelativistic matter dominates, and this epoch is responsible for the formation of
544:
1839:
of the expanding universe. The peculiar velocities of nonrelativistic particles decay as the universe expands, in inverse proportion with the cosmic
4833:
3103:– something that in principle must be observed – as there are no constraints that can simply be reasoned out (in other words there cannot be any
644:
4231:
Bolejko, Krzysztof; Wang, Chengyi; Lewis, Geraint F. (2019). "Direct detection of the cosmic expansion: The redshift drift and the flux drift".
2910:
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of distance from the observer, recessional velocity of objects at that distance increases by about 73 kilometres per second (160,000 mph).
2380:, because the rapid expansion would have diluted such relics. It was subsequently realized that the accelerated expansion would also solve the
1866:
The universe cools as it expands. This follows from the decay of particles' peculiar momenta, as discussed above. It can also be understood as
2958:
In part to accommodate such different geometries, the expansion of the universe is inherently general-relativistic. It cannot be modeled with
2360:
Inflation is a period of accelerated expansion hypothesized to have occurred at a time of around 10 seconds. It would have been driven by the
894:. Reiss's measurements on the recession velocity of the nearby Virgo Cluster more closely agree with subsequent and independent analyses of
2392:
during inflation would have created initial variations in the density of the universe, which gravity later amplified to yield the observed
614:
3195:
Animation of an expanding raisin-bread model. As the bread doubles in width (depth and length), the distances between raisins also double.
3003:
of Earth (or more precisely its location in space, even before it was formed). The yellow line is the worldline of the most distant known
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2821:
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3147:
all intents and purposes, it is safe to assume that the universe is infinite in spatial extent, without edge or strange connectedness.
2774:
2671:
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1850:
of both relativistic and nonrelativistic particles decay in inverse proportion with the scale factor. For photons, this leads to the
1130:, for a matter-dominated universe. The "acceleration" curve shows the trajectory of the scale factor for a universe with dark energy.
17:
3674:"Un Univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extra-galactiques"
1126:
The expansion history depends on the density of the universe. Ω on this graph corresponds to the ratio of the matter density to the
3676:[A homogeneous universe of constant mass and increasing radius accounting for the radial speed of extra-galactic nebulae].
697:
4719:
839:, allowing for sharper images and, consequently, more accurate analyses of its observations. Shortly after the repairs were made,
5198:
3261:
The situation changes somewhat with the introduction of dark energy or a cosmological constant. A cosmological constant due to a
2800:
798:
independently reached a similar conclusion to
Friedmann on a theoretical basis, and also presented observational evidence for a
4910:
3022:
valid in small regions of spacetime that are approximately flat. In particular, light always travels locally at the speed
740:
4728:
2516:
When an object is receding, its light gets stretched (redshifted). When the object is approaching, its light gets compressed (
2486:
1715:
1379:{\displaystyle {\frac {\ddot {a}}{a}}=-{\frac {4\pi G}{3}}\left(\rho +{\frac {3p}{c^{2}}}\right)+{\frac {\Lambda c^{2}}{3}},}
1146:
and inflation, exert gravitational repulsion in the cosmological context, which accelerates the expansion of the universe. A
5074:
3406:
2807:
920:
348:
2504:
Similarly to inflation, dark energy drives accelerated expansion, such that the scale factor grows exponentially in time.
5003:
1914:). The temperature of nonrelativistic matter drops more sharply, scaling as the inverse square of the scale factor (i.e.
3703:
3350:
universe can alternatively be thought of as corresponding only to the inertial motion of objects away from one another.
3054:
behavior originates from a special property of metric expansion, but rather from local principles of special relativity
2966:
exist, they may be at fundamental odds with the observed interaction between matter and spacetime seen in the universe.
2585:, another possibility is to infer the present-day expansion rate from the sizes of the largest fluctuations seen in the
3564:
2058:. This is because in addition to the volume dilution of the particle count, the energy of each particle (including the
825:
in Rome. For most of the second half of the 20th century, the value of the Hubble constant was estimated to be between
681:
2789:
4838:
4329:
4270:
3250:, which ignores the effects of gravity. In particular, general relativity predicts that light will move at the speed
3042:, whereas the latter distance (shown by the orange line) is about 28 billion light-years, much larger than
2944:
2858:
2840:
2738:
2685:
557:
3246:, the same geometry that describes the expansion of the universe as a whole and was also the basis for the simpler
1809:
822:
607:
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over most of its history, showing how a light ray (red line) can travel an effective distance of 28 billion
2627:), to measure the expansion rate. Such measurements do not yet have the precision to resolve the Hubble tension.
190:
3929:"First-Year Wilkinson Microwave Anisotropy Probe (WMAP)1 Observations: Determination of Cosmological Parameters"
1540:, and a positive pressure further decelerates expansion. On the other hand, sufficiently negative pressure with
5193:
4993:
4828:
4755:
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had its origin (that is, matter in the universe is separating because it was separating in the past due to the
3132:
an observational question that is constrained as measurable or non-measurable by the universe's global geometry
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552:
276:
266:
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2589:. A higher expansion rate would imply a smaller characteristic size of CMB fluctuations, and vice versa. The
2139:
1020:
195:
118:
2578:, supernova observations were used to determine that cosmic expansion is accelerating in the present epoch.
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Within the study of the evolution of structure within the universe, a natural scale emerges, known as the
835:
On 13 January 1994, NASA formally announced a completion of its repairs related to the main mirror of the
5183:
4854:
4576:
Baryshev, Yu. V. (2008). "Expanding Space: The Root of
Conceptual Problems of the Cosmological Physics".
3483:
3338:
2586:
2262:. For an exotic fluid with negative pressure, like dark energy, the energy density drops more slowly; if
2025:
1962:
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915:
600:
576:
123:
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The expansion of the universe can be understood as a consequence of an initial impulse (possibly due to
5105:
5049:
5034:
4859:
4795:
4486:
Whiting, Alan B. (2004). "The
Expansion of Space: Free Particle Motion and the Cosmological Redshift".
3167:
when very young and during part of its early expansion – far denser than is usually required to form a
3131:
2814:
1722:, which are defined to grow proportionally with the scale factor. If an object is moving only with the
1597:
536:
342:
322:
130:
75:
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2608:. There is a disagreement between this measurement and the supernova-based measurements, known as the
2443:
1508:
4748:
4734:
3874:
3171:– the universe did not re-collapse into a black hole. This is because commonly used calculations for
3105:
3099:
2636:
1917:
1881:
3526:
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817:
recalculated the size of the known universe in the 1940s, doubling the previous calculation made by
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2400:
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780:
772:
337:
102:
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that intersect with themselves, ultimately the question as to whether we are in something like a "
2713:
that states a
Knowledge editor's personal feelings or presents an original argument about a topic.
5059:
4256:
3358:
the ant's position over time will match the path of the red line on the embedding diagram above.
2950:"Geometrically flat" space has three dimensions and is consistent with Euclidean space. However,
2767:
305:
185:
4062:
1505:
is the cosmological constant. A positive energy density leads to deceleration of the expansion,
988:
959:
4967:
4262:
3172:
3135:
3134:. At present, observations are consistent with the universe having infinite extent and being a
3110:
2632:
2575:
2538:
2526:
2373:
1410:
949:
836:
807:
677:(FLRW), where it corresponds to an increase in the scale of the spatial part of the universe's
3928:
3766:
2372:
state. Inflation was originally proposed to explain the absence of exotic relics predicted by
2072:
1488:
5013:
4869:
4321:
3305:
3283:
3015:
2983:
2393:
2351:
2294:
1851:
1739:
1147:
1135:
941:
748:
704:
689:
660:
510:
312:
254:
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3828:
5044:
4683:
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3801:
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While special relativity prohibits objects from moving faster than light with respect to a
3232:
3139:
2530:
2231:
2101:
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1779:
1719:
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in 1929. He announced this finding to considerable astonishment at the 1952 meeting of the
523:
495:
317:
3321:, all done at constant local proper time. For example, galaxies that are farther than the
2265:
1587:
leads to accelerated expansion, and the cosmological constant also accelerates expansion.
8:
5167:
5064:
5018:
4895:
4805:
4785:
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3471:
Gibbons & Ellis, Classical and
Quantum Gravity 31 (2), 025003 (2014), arXiv:1308.1852
3313:
2894:
2887:
2620:
2590:
2534:
2420:
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2022:
For ultrarelativistic particles ("radiation"), the energy density drops more sharply, as
1790:
1746:
1256:
1225:
1180:
883:
776:
640:
415:
385:
332:
288:
180:
70:
4599:
4546:
4509:
4448:
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3897:
3805:
3689:
3577:
3539:
3496:
795:
455:
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4998:
4737:
at "Ask an
Astronomer" (the astronomer who provides this explanation is not specified).
4716:
4614:
4585:
4558:
4532:
4495:
4468:
4434:
4407:
4381:
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4016:
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3620:
3589:
3551:
3411:
3366:
2959:
2936:
2932:
2616:
2542:
2377:
2121:
1998:
1789:, and the region of the universe that lies within our particle horizon is known as the
1762:
1750:
1464:
1440:
1392:
1234:
1206:
1160:
1093:
1073:
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satellite (WMAP) further agreed with the estimated expansion rates for local galaxies,
708:
693:
685:
670:
475:
445:
410:
380:
327:
271:
40:
4523:
Bunn, E. F.; Hogg, D. W. (2009). "The kinematic origin of the cosmological redshift".
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4411:
4325:
4314:
4266:
4205:
4126:
4048:
4039:
4004:
3913:
3848:
3646:
3638:
3593:
3555:
3510:
3462:
Tipler, Monthly Notices of the Royal Astronomical Society 282(1), pp. 206–210 (1996).
3318:
2988:
2979:
2970:
2906:
1871:
1867:
1831:
1814:
1641:
1127:
899:
879:
656:
505:
4472:
4217:
3970:
3789:
3673:
3658:
3444:
Bunn & Hogg, American Journal of Physics 77, pp. 688–694 (2009), arXiv:0808.1081
3254:
with respect to the local motion of the exploding matter, a phenomenon analogous to
3206:
Once objects are bound by gravity, they no longer recede from each other. Thus, the
5131:
5093:
4972:
4562:
4550:
4452:
4399:
4197:
4170:
4114:
4034:
3958:
3901:
3809:
3630:
3581:
3543:
3207:
3143:
2898:
2582:
2385:
2059:
1786:
895:
868:
806:
observationally confirmed Lundmark's and Lemaître's findings in 1929. Assuming the
752:
588:
390:
226:
95:
4118:
4087:
Collaboration, Planck (2020). "Planck 2018 results. VI. Cosmological parameters".
400:
375:
4988:
4900:
4723:
4690:
4372:
Pons, J. M.; Talavera, P. (2021). "On cosmological expansion and local physics".
3309:
3294:
3287:
3236:
2921:
2381:
2365:
1588:
953:
852:
799:
663:
652:
515:
450:
435:
420:
405:
395:
259:
156:
3278:'s inflationary period, all the matter and energy in the universe was set on an
3118:
810:, these findings would imply that all galaxies are moving away from each other.
5119:
4696:
4665:
4403:
3835:. 813 Santa Barbara Street, Pasadena, California 91101.: Carnegie Observatories
3402:
3334:
3298:
3275:
3255:
3247:
2963:
2947:. Euclidean "geometrically flat" space has a Riemann curvature tensor of zero.
2609:
2412:
2321:
1855:
1805:
1482:
1434:
840:
800:
linear relationship between distance to galaxies and their recessional velocity
500:
460:
4201:
3585:
2876:
5177:
4464:
3870:""Using Type IA supernova light curve shapes to measure the Hubble constant""
3642:
3322:
3262:
3114:
3087:
2066:
1758:
1139:
911:
848:
787:
764:
632:
485:
470:
370:
1122:
5143:
5008:
4209:
3759:"Section 2: The Great Debate and the Great Mistake: Shapley, Hubble, Baade"
3650:
3227:
2993:
2369:
2016:
1840:
1718:
with the expansion of the universe factored out. This motivates the use of
1389:
shows how the contents of the universe influence its expansion rate. Here,
818:
814:
803:
490:
465:
440:
425:
281:
3608:
3317:
definition of distance used here is the summation or integration of local
3034:, as the red worldline illustrates. While it always moves locally at
2332:
952:. These constraints demand that any expansion of the universe accord with
666:
and does not limit the recession rates of cosmologically distant objects.
4962:
4952:
4500:
4439:
3945:
3888:
3243:
3223:
3219:
2498:
1836:
1754:
1727:
1723:
1252:
1143:
1111:
871:
844:
744:
732:
648:
238:
231:
4142:"Gravitational waves could soon provide measure of universe's expansion"
3239:", with which we would eventually merge if dark energy were not acting.
4957:
3992:
de Salas et al., Physical Review D. 92, 123534 (2015), arXiv:1511.00672
3723:
3547:
3330:
3326:
3168:
2902:
2781: in this section. Unsourced material may be challenged and removed.
2533:
is known. The object's distance can then be inferred from the observed
1714:
In an expanding universe, it is often useful to study the evolution of
1645:
875:
864:
480:
4554:
3481:
Slipher, V. M. (1913). "The Radial Velocity of the Andromeda Nebula".
4771:
3708:
3211:
3122:
3000:
2951:
2517:
2512:
2336:
A graphical representation of the expansion of the universe from the
945:
743:, and is still doing so. Physicists have postulated the existence of
716:
678:
430:
4731:
from the University of Winnipeg: an illustration, but no explanation
4456:
3634:
3453:
Lewis, Australian Physics 53(3), pp. 95–100 (2016), arXiv:1605.08634
3179:, and do not apply to rapidly expanding space such as the Big Bang.
3175:
are usually based upon objects of relatively constant size, such as
2973:
that show the large-scale geometry of the universe according to the
2756:
4915:
4800:
4790:
4717:
Hubble Tutorial from the University of Wisconsin Physics Department
4386:
4237:
4184:
4146:
4101:
4021:
3983:
Allahverdi et al., Open J. Astrophys. 4, 1 (2021), arXiv:2006.16182
3962:
3905:
3869:
3813:
3743:
Baade, W. (1956) "The period–luminosity relation of the Cepheids".
3094:
3083:
3079:
3071:
3055:
2624:
2482:
2432:
2361:
2355:
2337:
1847:
1458:
1153:
Mathematically, the expansion of the universe is quantified by the
768:
724:
712:
163:
65:
58:
4619:
4590:
4537:
3625:
3727:
3279:
3226:" and end up as bound, non-expanding objects up to the scales of
3164:
3126:
2062:) also drops significantly due to the decay of peculiar momenta.
4005:"A 2.4% Determination of the Local Value of the Hubble Constant"
2974:
783:
to provide theoretical evidence that the universe is expanding.
653:
speeds that are proportional to their distance from the observer
3004:
2642:
2567:
2541:
and the redshifts of their host galaxies. More recently, using
2436:
1591:
3407:"Cosmos Controversy: The Universe Is Expanding, but How Fast?"
3333:, away from us have a recession speed that is faster than the
3191:
4639:
The Expanding Universe: Astronomy's 'Great Debate', 1900–1931
3075:
3067:
4740:
4735:"Ant on a balloon" analogy to explain the expanding universe
2615:
A third option proposed recently is to use information from
48:
27:
Increase in distance between parts of the universe over time
4706:
4702:
3176:
3018:
of general relativity, the rules of special relativity are
2710:
personal reflection, personal essay, or argumentative essay
5138:
3704:"Astronomer sleuth solves mystery of Big Cosmos discovery"
775:
interpreted as galaxies receding from the Earth. In 1922,
4001:
2920:
At cosmological scales, the present universe conforms to
2647:
728:
4613:
Peacock, J. A. (2008). "A diatribe on expanding space".
3344:
1203:
at the present time. Because the universe is expanding,
4641:. Press Syndicate of the University of Cambridge, 1933.
3182:
3158:
2992:
similar effect can be seen in the tubular shape of the
1226:
this time at 13.787 ± 0.020 billion years ago
843:'s 1994 Key Project analyzed the recession velocity of
3456:
3269:
1698:
5103:
4427:
Publications of the Astronomical Society of Australia
3524:
Friedman, A. (1922). "Ăśber die KrĂĽmmung des Raumes".
2631:
changes in redshift or flux could be observed by the
2446:
2297:
2268:
2234:
2208:
2151:
2124:
2104:
2075:
2028:
2001:
1965:
1920:
1884:
1801:
induced by the repulsive gravity of the dark energy.
1654:
1600:
1546:
1511:
1491:
1467:
1443:
1419:
1395:
1268:
1237:
1209:
1183:
1163:
1096:
1076:
1023:
991:
962:
940:
The universe at the largest scales is observed to be
651:(which are bound to each other by gravity) recede at
3829:"The HST Key Project to Measure the Hubble Constant"
3295:
precise and regular form of the universe's expansion
2593:
measured the expansion rate this way and determined
2435:
as the universe expands, eventually nonrelativistic
2324:, the energy density grows as the universe expands.
755:, this acceleration becomes dominant in the future.
3730:, and the central region of the Andromeda nebula".
3562:Friedmann, A. (1999). "On the Curvature of Space".
1874:fluids, often called "radiation" and including the
1820:
4313:
4288:"What Do You Mean, The Universe Is Flat? (Part I)"
3109:constraints) on how the space in which we live is
2473:
2312:
2283:
2254:
2220:
2191:
2130:
2110:
2090:
2050:
2007:
1987:
1942:
1906:
1684:
1632:
1579:
1532:
1497:
1473:
1449:
1425:
1401:
1378:
1243:
1215:
1195:
1169:
1102:
1082:
1059:
1006:
977:
948:(the same in all directions), consistent with the
4684:Answer to a question about the expanding universe
3440:
3438:
2905:(orange line) in just 13.8 billion years of
5175:
4646:Cosmological Inflation and Large-Scale Structure
4418:
4230:
4167:
3986:
3977:
935:
4424:
4344:
3678:Annales de la Société Scientifique de Bruxelles
3447:
2507:
1878:, scales inversely with the scale factor (i.e.
1117:
791:was within 1% of the best measurements today."
767:discovered that light from remote galaxies was
659:, this limitation applies only with respect to
3465:
3435:
3426:
3061:
2142:. The energy density of such a fluid drops as
4756:
4651:Lineweaver, Charles H. and Davis, Tamara M. "
4133:
4086:
3117:. Though certain cosmological models such as
608:
4371:
4161:
2643:Conceptual considerations and misconceptions
2529:, which is an object or event for which the
1255:, and its time evolution is governed by the
673:. It can be modeled mathematically with the
3933:The Astrophysical Journal Supplement Series
3395:
2686:Learn how and when to remove these messages
2581:By assuming a cosmological model, e.g. the
1825:
4763:
4749:
3113:or whether it wraps around on itself as a
2969:The images to the right show two views of
918:during the first year observations of the
675:Friedmann–Lemaître–Robertson–Walker metric
615:
601:
47:
4834:Religious interpretations of the Big Bang
4618:
4589:
4536:
4499:
4438:
4385:
4236:
4183:
4100:
4038:
4020:
3995:
3944:
3887:
3624:
3561:
3218:us and is not expanding away. Within the
2859:Learn how and when to remove this message
2841:Learn how and when to remove this message
2739:Learn how and when to remove this message
2192:{\displaystyle \rho \propto a^{-3(1+w)}.}
985:scale with (observer-centered) positions
4824:Discovery of cosmic microwave background
4575:
4569:
4522:
4285:
4279:
3671:
3523:
3312:, it does not apply to situations where
3190:
2545:, the expansion rate was measured to be
2511:
2331:
1773:
1733:
1121:
882:. This further minimized the systematic
688:description but rather only a choice of
655:, on average. While objects cannot move
4612:
4606:
4485:
4479:
4311:
3926:
3787:
3480:
3401:
2619:events (especially those involving the
1703:
1060:{\displaystyle {\vec {v}}=H{\vec {x}},}
902:, which estimates a Hubble constant of
14:
5176:
4711:Explanation of the universal expansion
4347:"What is the universe expanding into?"
4320:. Princeton University Press. p.
4251:
4139:
2648:Measuring distances in expanding space
4744:
4644:Liddle, Andrew R. and Lyth, David H.
4631:
3867:
3790:""The on-orbit performance of WFPC2""
3763:The Cepheid Distance Scale: A History
3606:
3511:"Vesto Slipher – American astronomer"
3345:Common analogies for cosmic expansion
2999:The brown line on the diagram is the
2487:large-scale structure of the universe
2394:spectrum of matter density variations
2118:is the energy density. The parameter
669:Cosmic expansion is a key feature of
4516:
3826:
3722:Baade, W. (1944) "The resolution of
3609:"Who discovered Universe expansion?"
3373:expansion has a center and an edge.
3183:Effects of expansion on small scales
3159:Density of universe during expansion
2779:adding citations to reliable sources
2750:
2692:
2651:
2566:. This means that for every million
2327:
921:Wilkinson Microwave Anisotropy Probe
4672:. Princeton University Press, 1991.
4648:. Cambridge University Press, 2000.
4349:. Ask an Astronomer. Archived from
3270:Metric expansion and speed of light
2345:
2051:{\displaystyle \rho \propto a^{-4}}
1988:{\displaystyle \rho \propto a^{-3}}
1797:never reach us, because there is a
1699:Distances in the expanding universe
874:shapes to more finely estimate the
867:et al. used an empirical method of
24:
4374:General Relativity and Gravitation
4140:Lerner, Louise (22 October 2018).
3565:General Relativity and Gravitation
3308:where spacetime can be treated as
2406:
1594:is essentially pressureless, with
1580:{\displaystyle p<-\rho c^{2}/3}
1492:
1354:
1090:quantifies the rate of expansion.
343:2dF Galaxy Redshift Survey ("2dF")
25:
5210:
4839:Timeline of cosmological theories
4676:
4653:Misconceptions about the Big Bang
4345:Rothstein, Dave (23 April 2003).
4063:"The Nobel Prize in Physics 2011"
3927:Spergel, D. N. (September 2003).
3756:
2945:curvature of Riemannian manifolds
2667:This article has multiple issues.
2415:particles, conventionally called
1633:{\displaystyle |p|\ll \rho c^{2}}
1259:. The second Friedmann equation,
731:) to one approximately 10.6
558:Timeline of cosmological theories
323:Cosmic Background Explorer (COBE)
5161:
5149:
5137:
5125:
5113:
5087:
4661:, March 2005 (non-free content).
4316:Principles of Physical Cosmology
4292:Scientific American Blog Network
2928:, to within experimental error.
2924:, what cosmologists describe as
2886:
2875:
2755:
2697:
2656:
2474:{\displaystyle a\propto t^{2/3}}
2291:it remains constant in time. If
1821:Consequences of cosmic expansion
1815:Newtonian gravitational dynamics
1533:{\displaystyle {\ddot {a}}<0}
823:International Astronomical Union
582:
571:
570:
4932:Future of an expanding universe
4365:
4338:
4305:
4245:
4224:
4080:
4055:
3920:
3868:Riess, Adam G. (January 1995).
3861:
3820:
3781:
3750:
3737:
3716:
3696:
3665:
3600:
3432:Peacock (2008), arXiv:0809.4573
2766:needs additional citations for
2675:or discuss these issues on the
2426:
1943:{\displaystyle T\propto a^{-2}}
1907:{\displaystyle T\propto a^{-1}}
711:about 10 of a second after the
338:Sloan Digital Sky Survey (SDSS)
191:Future of an expanding universe
5199:Physical cosmological concepts
4829:History of the Big Bang theory
3517:
3503:
3474:
2492:
2181:
2169:
2065:In general, we can consider a
1861:
1685:{\displaystyle p=\rho c^{2}/3}
1610:
1602:
1048:
1030:
998:
969:
553:History of the Big Bang theory
349:Wilkinson Microwave Anisotropy
13:
1:
4937:Ultimate fate of the universe
4865:Gravitational wave background
4770:
3794:Astrophysical Journal Letters
3388:
3383:Comoving and proper distances
2399:During inflation, the cosmic
1846:More generally, the peculiar
936:Structure of cosmic expansion
545:Discovery of cosmic microwave
196:Ultimate fate of the universe
4089:Astronomy & Astrophysics
3291:general theory of relativity
2508:Measuring the expansion rate
1749:. In a universe governed by
1118:Dynamics of cosmic expansion
723:, about half the width of a
7:
4855:Cosmic microwave background
4525:American Journal of Physics
4119:10.1051/0004-6361/201833910
3607:Steer, Ian (October 2012).
3484:Lowell Observatory Bulletin
3376:
3062:Topology of expanding space
2931:Consequently, the rules of
2790:"Expansion of the universe"
2587:cosmic microwave background
2368:that has a positive-energy
2202:Nonrelativistic matter has
2140:equation of state parameter
1876:cosmic microwave background
916:cosmic microwave background
886:of the Hubble constant, to
313:Black Hole Initiative (BHI)
10:
5215:
4860:Cosmic neutrino background
4796:Chronology of the universe
4404:10.1007/s10714-021-02874-4
4312:Peebles, P. J. E. (1993).
4040:10.3847/0004-637X/826/1/56
3672:Lemaître, Georges (1927).
3339:cosmological event horizon
2496:
2349:
1953:
1810:Cosmological perturbations
1777:
1737:
1707:
1007:{\displaystyle {\vec {x}}}
978:{\displaystyle {\vec {v}}}
944:(the same everywhere) and
758:
696:, it is also predicted by
76:Chronology of the universe
5083:
5027:
4981:
4945:
4924:
4906:Expansion of the universe
4883:
4847:
4814:
4778:
4713:" at an elementary level.
4202:10.1038/s41586-018-0606-0
4009:The Astrophysical Journal
3875:The Astrophysical Journal
3325:, approximately 4.5
3074:is expanding. The words '
2637:Extremely Large Telescope
1753:, such surfaces would be
629:expansion of the universe
169:Expansion of the universe
18:Metric expansion of space
3853:: CS1 maint: location (
3210:, which is bound to the
3163:Despite being extremely
2941:Riemann curvature tensor
2937:Euclid's fifth postulate
2091:{\displaystyle p=w\rho }
1826:Velocities and redshifts
1648:) has positive pressure
1498:{\displaystyle \Lambda }
781:Einstein field equations
333:Planck space observatory
119:Gravitational wave (GWB)
5060:Observational cosmology
4689:11 January 2009 at the
4258:A Universe from Nothing
4111:2020A&A...641A...6P
3788:Trauger, J. T. (1994).
3586:10.1023/A:1026751225741
3058:over a curved surface.
2621:merger of neutron stars
2313:{\displaystyle w<-1}
1757:, because relativistic
863:. Later the same year,
637:gravitationally unbound
186:Inhomogeneous cosmology
4911:Accelerating expansion
4729:Expanding raisin bread
4697:The Expanding universe
4286:Castelvecchi, Davide.
4261:. Free Press. p.
3527:Zeitschrift fĂĽr Physik
3214:, is actually falling
3196:
3173:gravitational collapse
3136:simply connected space
2984:accelerating expansion
2719:by rewriting it in an
2633:Square Kilometre Array
2576:Nobel Prize in Physics
2539:Cepheid variable stars
2521:
2475:
2374:grand unified theories
2342:
2314:
2285:
2256:
2222:
2193:
2132:
2112:
2092:
2052:
2009:
1989:
1944:
1908:
1686:
1634:
1581:
1534:
1499:
1475:
1451:
1427:
1411:gravitational constant
1403:
1380:
1251:is a parameter of the
1245:
1217:
1197:
1171:
1150:also has this effect.
1131:
1104:
1084:
1070:where the Hubble rate
1061:
1008:
979:
950:cosmological principle
837:Hubble Space Telescope
808:cosmological principle
5194:Concepts in astronomy
5014:Shape of the universe
5004:Large-scale structure
4817:cosmological theories
3329:or 14.7 billion
3306:local reference frame
3284:equivalence principle
3194:
3140:cosmological horizons
3016:equivalence principle
2515:
2476:
2352:inflation (cosmology)
2335:
2315:
2286:
2257:
2255:{\displaystyle w=1/3}
2223:
2194:
2133:
2113:
2111:{\displaystyle \rho }
2093:
2053:
2010:
1990:
1945:
1909:
1870:. The temperature of
1852:cosmological redshift
1774:Cosmological horizons
1765:, the shape of these
1740:Shape of the universe
1734:Shape of the universe
1687:
1644:particles (such as a
1635:
1582:
1535:
1500:
1476:
1452:
1437:within the universe,
1428:
1426:{\displaystyle \rho }
1404:
1381:
1246:
1218:
1198:
1172:
1148:cosmological constant
1125:
1105:
1085:
1062:
1009:
980:
847:from the core of the
749:cosmological constant
277:Large-scale structure
255:Shape of the universe
5094:astronomy portal
3405:(20 February 2017).
3355:ant on a rubber rope
3282:consistent with the
3233:Shapley Supercluster
3121:even permit bizarre
2911:Mathematical details
2775:improve this article
2591:Planck collaboration
2564:1.74 (km/s)/Mpc
2531:intrinsic brightness
2444:
2390:quantum fluctuations
2295:
2284:{\displaystyle w=-1}
2266:
2232:
2228:while radiation has
2206:
2149:
2122:
2102:
2073:
2026:
1999:
1963:
1918:
1882:
1799:cosmic event horizon
1780:Cosmological horizon
1767:comoving synchronous
1720:comoving coordinates
1710:Comoving coordinates
1704:Comoving coordinates
1652:
1598:
1544:
1509:
1489:
1465:
1441:
1417:
1393:
1266:
1235:
1207:
1181:
1161:
1094:
1074:
1021:
989:
960:
827:50 and 90 kmâ‹…sâ‹…
649:the nearest galaxies
643:with time. It is an
589:Astronomy portal
547:background radiation
524:List of cosmologists
5019:Structure formation
4982:Structure formation
4896:Friedmann equations
4806:Observable universe
4786:Age of the universe
4722:9 June 2014 at the
4658:Scientific American
4637:Eddington, Arthur.
4600:2008pc2..conf...20B
4578:Practical Cosmology
4547:2009AmJPh..77..688B
4510:2004Obs...124..174W
4449:2004PASA...21...97D
4396:2021GReGr..53..105P
4253:Krauss, Lawrence M.
4194:2018Natur.562..545C
4031:2016ApJ...826...56R
3955:2003ApJS..148..175S
3898:1995ApJ...438L..17R
3806:1994ApJ...435L...3T
3769:on 10 December 2007
3712:. 14 November 2011.
3690:1927ASSB...47...49L
3578:1999GReGr..31.1991F
3540:1922ZPhy...10..377F
3497:1913LowOB...2...56S
3314:spacetime curvature
3310:flat and unchanging
3293:. This is when the
3280:inertial trajectory
2895:isometric embedding
2606:0.5 (km/s)/Mpc
2535:apparent brightness
2421:neutrino decoupling
2320:, corresponding to
2221:{\displaystyle w=0}
1791:observable universe
1747:age of the universe
1257:Friedmann equations
1196:{\displaystyle a=1}
1140:relativistic fluids
914:'s analysis of the
786:Swedish astronomer
777:Alexander Friedmann
741:expand more quickly
686:generally covariant
641:observable universe
631:is the increase in
289:Structure formation
181:Friedmann equations
71:Age of the universe
35:Part of a series on
5184:General relativity
4999:Large quasar group
4664:Mook, Delo E. and
4632:Printed references
3548:10.1007/BF01332580
3412:The New York Times
3367:Gaussian curvature
3319:comoving distances
3274:At the end of the
3197:
3144:inflationary model
3070:that makes up the
2971:spacetime diagrams
2960:special relativity
2933:Euclidean geometry
2926:geometrically flat
2721:encyclopedic style
2708:is written like a
2639:in the mid-2030s.
2617:gravitational wave
2543:Type Ia supernovae
2522:
2471:
2378:magnetic monopoles
2343:
2310:
2281:
2252:
2218:
2189:
2128:
2108:
2088:
2048:
2005:
1985:
1940:
1904:
1763:general relativity
1751:special relativity
1682:
1630:
1577:
1530:
1495:
1471:
1447:
1423:
1399:
1376:
1241:
1213:
1193:
1167:
1132:
1100:
1080:
1057:
1004:
975:
884:measurement errors
880:Type Ia supernovae
709:inflationary epoch
694:general relativity
671:Big Bang cosmology
328:Dark Energy Survey
272:Large quasar group
41:Physical cosmology
5101:
5100:
5055:Illustris project
4670:Inside Relativity
4555:10.1119/1.3129103
4178:(7728): 545–547.
3572:(12): 1991–2000.
3014:According to the
2989:comoving distance
2980:cosmological time
2907:cosmological time
2869:
2868:
2861:
2851:
2850:
2843:
2825:
2749:
2748:
2741:
2690:
2419:, by the time of
2328:Expansion history
2131:{\displaystyle w}
2008:{\displaystyle a}
1872:ultrarelativistic
1868:adiabatic cooling
1832:peculiar velocity
1642:ultrarelativistic
1640:, while a gas of
1521:
1474:{\displaystyle c}
1450:{\displaystyle p}
1402:{\displaystyle G}
1371:
1341:
1308:
1284:
1279:
1244:{\displaystyle a}
1231:The scale factor
1216:{\displaystyle a}
1170:{\displaystyle a}
1110:is a function of
1103:{\displaystyle H}
1083:{\displaystyle H}
1051:
1033:
1001:
972:
900:Type Ia supernova
747:, appearing as a
698:Newtonian gravity
657:faster than light
625:
624:
296:
295:
138:
137:
16:(Redirected from
5206:
5166:
5165:
5164:
5154:
5153:
5152:
5142:
5141:
5130:
5129:
5128:
5118:
5117:
5109:
5092:
5091:
5090:
4994:Galaxy formation
4973:Lambda-CDM model
4884:Present universe
4765:
4758:
4751:
4742:
4741:
4709:team offers an "
4625:
4624:
4622:
4610:
4604:
4603:
4593:
4573:
4567:
4566:
4540:
4520:
4514:
4513:
4503:
4501:astro-ph/0404095
4483:
4477:
4476:
4442:
4440:astro-ph/0310808
4422:
4416:
4415:
4389:
4369:
4363:
4362:
4360:
4358:
4342:
4336:
4335:
4319:
4309:
4303:
4302:
4300:
4298:
4283:
4277:
4276:
4249:
4243:
4242:
4240:
4228:
4222:
4221:
4187:
4165:
4159:
4158:
4156:
4154:
4137:
4131:
4130:
4104:
4084:
4078:
4077:
4075:
4073:
4059:
4053:
4052:
4042:
4024:
3999:
3993:
3990:
3984:
3981:
3975:
3974:
3948:
3946:astro-ph/0302209
3924:
3918:
3917:
3891:
3889:astro-ph/9410054
3865:
3859:
3858:
3852:
3844:
3842:
3840:
3827:Freedman, W. L.
3824:
3818:
3817:
3785:
3779:
3778:
3776:
3774:
3765:. Archived from
3754:
3748:
3741:
3735:
3720:
3714:
3713:
3700:
3694:
3693:
3669:
3663:
3662:
3628:
3604:
3598:
3597:
3559:
3521:
3515:
3514:
3507:
3501:
3500:
3478:
3472:
3469:
3463:
3460:
3454:
3451:
3445:
3442:
3433:
3430:
3424:
3423:
3421:
3419:
3399:
3212:Milky Way Galaxy
3208:Andromeda Galaxy
3119:Gödel's universe
2935:associated with
2899:visible universe
2893:Two views of an
2890:
2879:
2864:
2857:
2846:
2839:
2835:
2832:
2826:
2824:
2783:
2759:
2751:
2744:
2737:
2733:
2730:
2724:
2701:
2700:
2693:
2682:
2660:
2659:
2652:
2607:
2605:
2583:Lambda-CDM model
2565:
2563:
2558:
2554:
2480:
2478:
2477:
2472:
2470:
2469:
2465:
2431:Since radiation
2388:. Additionally,
2386:flatness problem
2346:Cosmic inflation
2319:
2317:
2316:
2311:
2290:
2288:
2287:
2282:
2261:
2259:
2258:
2253:
2248:
2227:
2225:
2224:
2219:
2198:
2196:
2195:
2190:
2185:
2184:
2137:
2135:
2134:
2129:
2117:
2115:
2114:
2109:
2097:
2095:
2094:
2089:
2060:rest mass energy
2057:
2055:
2054:
2049:
2047:
2046:
2014:
2012:
2011:
2006:
1994:
1992:
1991:
1986:
1984:
1983:
1949:
1947:
1946:
1941:
1939:
1938:
1913:
1911:
1910:
1905:
1903:
1902:
1787:particle horizon
1691:
1689:
1688:
1683:
1678:
1673:
1672:
1639:
1637:
1636:
1631:
1629:
1628:
1613:
1605:
1586:
1584:
1583:
1578:
1573:
1568:
1567:
1539:
1537:
1536:
1531:
1523:
1522:
1514:
1504:
1502:
1501:
1496:
1480:
1478:
1477:
1472:
1456:
1454:
1453:
1448:
1432:
1430:
1429:
1424:
1408:
1406:
1405:
1400:
1385:
1383:
1382:
1377:
1372:
1367:
1366:
1365:
1352:
1347:
1343:
1342:
1340:
1339:
1330:
1322:
1309:
1304:
1293:
1285:
1280:
1272:
1270:
1250:
1248:
1247:
1242:
1222:
1220:
1219:
1214:
1202:
1200:
1199:
1194:
1176:
1174:
1173:
1168:
1128:critical density
1109:
1107:
1106:
1101:
1089:
1087:
1086:
1081:
1066:
1064:
1063:
1058:
1053:
1052:
1044:
1035:
1034:
1026:
1013:
1011:
1010:
1005:
1003:
1002:
994:
984:
982:
981:
976:
974:
973:
965:
931:
929:
909:
907:
898:calibrations of
896:Cepheid variable
893:
891:
862:
861:17 kmâ‹…sâ‹…Mpc
860:
831:
796:Georges Lemaître
753:Lambda-CDM model
738:
722:
705:inflation theory
664:reference frames
617:
610:
603:
587:
586:
585:
574:
573:
267:Galaxy formation
227:Lambda-CDM model
216:
215:
208:Components
90:
89:
51:
32:
31:
21:
5214:
5213:
5209:
5208:
5207:
5205:
5204:
5203:
5174:
5173:
5172:
5162:
5160:
5150:
5148:
5136:
5126:
5124:
5112:
5104:
5102:
5097:
5088:
5086:
5079:
5023:
4989:Galaxy filament
4977:
4941:
4925:Future universe
4920:
4879:
4875:Nucleosynthesis
4843:
4816:
4810:
4774:
4769:
4724:Wayback Machine
4695:Felder, Gary, "
4691:Wayback Machine
4679:
4634:
4629:
4628:
4611:
4607:
4574:
4570:
4521:
4517:
4488:The Observatory
4484:
4480:
4457:10.1071/AS03040
4423:
4419:
4370:
4366:
4356:
4354:
4343:
4339:
4332:
4310:
4306:
4296:
4294:
4284:
4280:
4273:
4250:
4246:
4229:
4225:
4166:
4162:
4152:
4150:
4138:
4134:
4085:
4081:
4071:
4069:
4061:
4060:
4056:
4000:
3996:
3991:
3987:
3982:
3978:
3925:
3921:
3866:
3862:
3846:
3845:
3838:
3836:
3825:
3821:
3786:
3782:
3772:
3770:
3755:
3751:
3742:
3738:
3721:
3717:
3702:
3701:
3697:
3670:
3666:
3635:10.1038/490176c
3605:
3601:
3560:translated in
3522:
3518:
3509:
3508:
3504:
3479:
3475:
3470:
3466:
3461:
3457:
3452:
3448:
3443:
3436:
3431:
3427:
3417:
3415:
3403:Overbye, Dennis
3400:
3396:
3391:
3379:
3347:
3272:
3237:Great Attractor
3200:them to do so.
3185:
3161:
3088:various strings
3066:Over time, the
3064:
2922:Euclidean space
2918:
2917:
2916:
2915:
2914:
2897:of part of the
2891:
2882:
2881:
2880:
2865:
2854:
2853:
2852:
2847:
2836:
2830:
2827:
2784:
2782:
2772:
2760:
2745:
2734:
2728:
2725:
2717:help improve it
2714:
2702:
2698:
2661:
2657:
2650:
2645:
2603:
2601:
2599:
2561:
2559:
2556:
2552:
2551:
2527:standard candle
2510:
2501:
2495:
2461:
2457:
2453:
2445:
2442:
2441:
2429:
2409:
2407:Radiation epoch
2382:horizon problem
2358:
2350:Main articles:
2348:
2330:
2296:
2293:
2292:
2267:
2264:
2263:
2244:
2233:
2230:
2229:
2207:
2204:
2203:
2162:
2158:
2150:
2147:
2146:
2123:
2120:
2119:
2103:
2100:
2099:
2074:
2071:
2070:
2039:
2035:
2027:
2024:
2023:
2000:
1997:
1996:
1976:
1972:
1964:
1961:
1960:
1956:
1931:
1927:
1919:
1916:
1915:
1895:
1891:
1883:
1880:
1879:
1864:
1828:
1823:
1782:
1776:
1742:
1736:
1712:
1706:
1701:
1695:
1674:
1668:
1664:
1653:
1650:
1649:
1624:
1620:
1609:
1601:
1599:
1596:
1595:
1589:Nonrelativistic
1569:
1563:
1559:
1545:
1542:
1541:
1513:
1512:
1510:
1507:
1506:
1490:
1487:
1486:
1466:
1463:
1462:
1442:
1439:
1438:
1418:
1415:
1414:
1394:
1391:
1390:
1361:
1357:
1353:
1351:
1335:
1331:
1323:
1321:
1314:
1310:
1294:
1292:
1271:
1269:
1267:
1264:
1263:
1236:
1233:
1232:
1208:
1205:
1204:
1182:
1179:
1178:
1162:
1159:
1158:
1120:
1095:
1092:
1091:
1075:
1072:
1071:
1043:
1042:
1025:
1024:
1022:
1019:
1018:
993:
992:
990:
987:
986:
964:
963:
961:
958:
957:
938:
930:5 kmâ‹…sâ‹…Mpc
927:
925:
908:7 kmâ‹…sâ‹…Mpc
905:
903:
892:7 kmâ‹…sâ‹…Mpc
889:
887:
858:
856:
855:measurement of
853:Hubble constant
826:
771:, a phenomenon
761:
736:
720:
621:
583:
581:
563:
562:
549:
546:
539:
537:Subject history
529:
528:
520:
365:
357:
356:
353:
350:
308:
298:
297:
260:Galaxy filament
213:
201:
200:
152:
147:Expansion
140:
139:
124:Microwave (CMB)
103:Nucleosynthesis
87:
28:
23:
22:
15:
12:
11:
5:
5212:
5202:
5201:
5196:
5191:
5186:
5171:
5170:
5158:
5146:
5134:
5122:
5099:
5098:
5084:
5081:
5080:
5078:
5077:
5072:
5067:
5062:
5057:
5052:
5047:
5042:
5037:
5031:
5029:
5025:
5024:
5022:
5021:
5016:
5011:
5006:
5001:
4996:
4991:
4985:
4983:
4979:
4978:
4976:
4975:
4970:
4965:
4960:
4955:
4949:
4947:
4943:
4942:
4940:
4939:
4934:
4928:
4926:
4922:
4921:
4919:
4918:
4913:
4908:
4903:
4898:
4893:
4887:
4885:
4881:
4880:
4878:
4877:
4872:
4867:
4862:
4857:
4851:
4849:
4845:
4844:
4842:
4841:
4836:
4831:
4826:
4820:
4818:
4812:
4811:
4809:
4808:
4803:
4798:
4793:
4788:
4782:
4780:
4776:
4775:
4768:
4767:
4760:
4753:
4745:
4739:
4738:
4732:
4726:
4714:
4700:
4693:
4682:Swenson, Jim,
4678:
4677:External links
4675:
4674:
4673:
4666:Thomas Vargish
4662:
4649:
4642:
4633:
4630:
4627:
4626:
4605:
4568:
4531:(8): 688–694.
4515:
4478:
4417:
4364:
4353:on 8 June 2020
4337:
4330:
4304:
4278:
4271:
4244:
4223:
4160:
4132:
4079:
4067:NobelPrize.org
4054:
3994:
3985:
3976:
3963:10.1086/377226
3939:(1): 175–194.
3919:
3906:10.1086/187704
3860:
3819:
3814:10.1086/187580
3780:
3749:
3736:
3715:
3695:
3664:
3599:
3534:(1): 377–386.
3516:
3502:
3473:
3464:
3455:
3446:
3434:
3425:
3393:
3392:
3390:
3387:
3386:
3385:
3378:
3375:
3346:
3343:
3335:speed of light
3299:inflaton field
3276:early universe
3271:
3268:
3256:frame dragging
3248:Milne universe
3184:
3181:
3160:
3157:
3063:
3060:
2962:alone: Though
2892:
2885:
2884:
2883:
2874:
2873:
2872:
2871:
2870:
2867:
2866:
2849:
2848:
2763:
2761:
2754:
2747:
2746:
2705:
2703:
2696:
2691:
2665:
2664:
2662:
2655:
2649:
2646:
2644:
2641:
2610:Hubble tension
2597:
2549:
2509:
2506:
2497:Main article:
2494:
2491:
2468:
2464:
2460:
2456:
2452:
2449:
2428:
2425:
2413:Standard Model
2408:
2405:
2347:
2344:
2329:
2326:
2322:phantom energy
2309:
2306:
2303:
2300:
2280:
2277:
2274:
2271:
2251:
2247:
2243:
2240:
2237:
2217:
2214:
2211:
2200:
2199:
2188:
2183:
2180:
2177:
2174:
2171:
2168:
2165:
2161:
2157:
2154:
2127:
2107:
2087:
2084:
2081:
2078:
2069:with pressure
2045:
2042:
2038:
2034:
2031:
2004:
1982:
1979:
1975:
1971:
1968:
1955:
1952:
1937:
1934:
1930:
1926:
1923:
1901:
1898:
1894:
1890:
1887:
1863:
1860:
1856:Doppler effect
1827:
1824:
1822:
1819:
1806:Hubble horizon
1778:Main article:
1775:
1772:
1738:Main article:
1735:
1732:
1708:Main article:
1705:
1702:
1700:
1697:
1681:
1677:
1671:
1667:
1663:
1660:
1657:
1627:
1623:
1619:
1616:
1612:
1608:
1604:
1576:
1572:
1566:
1562:
1558:
1555:
1552:
1549:
1529:
1526:
1520:
1517:
1494:
1483:speed of light
1470:
1446:
1435:energy density
1422:
1398:
1387:
1386:
1375:
1370:
1364:
1360:
1356:
1350:
1346:
1338:
1334:
1329:
1326:
1320:
1317:
1313:
1307:
1303:
1300:
1297:
1291:
1288:
1283:
1278:
1275:
1240:
1212:
1192:
1189:
1186:
1166:
1119:
1116:
1099:
1079:
1068:
1067:
1056:
1050:
1047:
1041:
1038:
1032:
1029:
1000:
997:
971:
968:
937:
934:
841:Wendy Freedman
763:In 1912–1914,
760:
757:
735:across (about
623:
622:
620:
619:
612:
605:
597:
594:
593:
592:
591:
579:
565:
564:
561:
560:
555:
550:
543:
540:
535:
534:
531:
530:
527:
526:
519:
518:
513:
508:
503:
498:
493:
488:
483:
478:
473:
468:
463:
458:
453:
448:
443:
438:
433:
428:
423:
418:
413:
408:
403:
398:
393:
388:
383:
378:
373:
367:
366:
363:
362:
359:
358:
355:
354:
347:
345:
340:
335:
330:
325:
320:
315:
309:
304:
303:
300:
299:
294:
293:
292:
291:
279:
274:
269:
257:
249:
248:
244:
243:
242:
241:
229:
221:
220:
214:
207:
206:
203:
202:
199:
198:
193:
188:
183:
171:
166:
153:
146:
145:
142:
141:
136:
135:
134:
133:
131:Neutrino (CNB)
121:
113:
112:
108:
107:
106:
105:
88:
86:Early universe
85:
84:
81:
80:
79:
78:
73:
68:
53:
52:
44:
43:
37:
36:
26:
9:
6:
4:
3:
2:
5211:
5200:
5197:
5195:
5192:
5190:
5187:
5185:
5182:
5181:
5179:
5169:
5159:
5157:
5147:
5145:
5140:
5135:
5133:
5123:
5121:
5116:
5111:
5110:
5107:
5096:
5095:
5082:
5076:
5073:
5071:
5068:
5066:
5063:
5061:
5058:
5056:
5053:
5051:
5048:
5046:
5043:
5041:
5038:
5036:
5033:
5032:
5030:
5026:
5020:
5017:
5015:
5012:
5010:
5007:
5005:
5002:
5000:
4997:
4995:
4992:
4990:
4987:
4986:
4984:
4980:
4974:
4971:
4969:
4966:
4964:
4961:
4959:
4956:
4954:
4951:
4950:
4948:
4944:
4938:
4935:
4933:
4930:
4929:
4927:
4923:
4917:
4914:
4912:
4909:
4907:
4904:
4902:
4899:
4897:
4894:
4892:
4889:
4888:
4886:
4882:
4876:
4873:
4871:
4868:
4866:
4863:
4861:
4858:
4856:
4853:
4852:
4850:
4848:Past universe
4846:
4840:
4837:
4835:
4832:
4830:
4827:
4825:
4822:
4821:
4819:
4813:
4807:
4804:
4802:
4799:
4797:
4794:
4792:
4789:
4787:
4784:
4783:
4781:
4777:
4773:
4766:
4761:
4759:
4754:
4752:
4747:
4746:
4743:
4736:
4733:
4730:
4727:
4725:
4721:
4718:
4715:
4712:
4708:
4704:
4701:
4698:
4694:
4692:
4688:
4685:
4681:
4680:
4671:
4667:
4663:
4660:
4659:
4654:
4650:
4647:
4643:
4640:
4636:
4635:
4621:
4616:
4609:
4601:
4597:
4592:
4587:
4583:
4579:
4572:
4564:
4560:
4556:
4552:
4548:
4544:
4539:
4534:
4530:
4526:
4519:
4511:
4507:
4502:
4497:
4493:
4489:
4482:
4474:
4470:
4466:
4462:
4458:
4454:
4450:
4446:
4441:
4436:
4433:(1): 97–109.
4432:
4428:
4421:
4413:
4409:
4405:
4401:
4397:
4393:
4388:
4383:
4379:
4375:
4368:
4352:
4348:
4341:
4333:
4331:9780691019338
4327:
4323:
4318:
4317:
4308:
4293:
4289:
4282:
4274:
4272:9781451624458
4268:
4264:
4260:
4259:
4254:
4248:
4239:
4234:
4227:
4219:
4215:
4211:
4207:
4203:
4199:
4195:
4191:
4186:
4181:
4177:
4173:
4172:
4164:
4149:
4148:
4143:
4136:
4128:
4124:
4120:
4116:
4112:
4108:
4103:
4098:
4094:
4090:
4083:
4068:
4064:
4058:
4050:
4046:
4041:
4036:
4032:
4028:
4023:
4018:
4014:
4010:
4006:
3998:
3989:
3980:
3972:
3968:
3964:
3960:
3956:
3952:
3947:
3942:
3938:
3934:
3930:
3923:
3915:
3911:
3907:
3903:
3899:
3895:
3890:
3885:
3881:
3877:
3876:
3871:
3864:
3856:
3850:
3834:
3833:www.stsci.edu
3830:
3823:
3815:
3811:
3807:
3803:
3799:
3795:
3791:
3784:
3768:
3764:
3760:
3757:Allen, Nick.
3753:
3746:
3740:
3734:. pp. 137–146
3733:
3729:
3725:
3719:
3711:
3710:
3705:
3699:
3691:
3687:
3683:
3679:
3675:
3668:
3660:
3656:
3652:
3648:
3644:
3640:
3636:
3632:
3627:
3622:
3619:(7419): 176.
3618:
3614:
3610:
3603:
3595:
3591:
3587:
3583:
3579:
3575:
3571:
3567:
3566:
3557:
3553:
3549:
3545:
3541:
3537:
3533:
3529:
3528:
3520:
3512:
3506:
3498:
3494:
3490:
3486:
3485:
3477:
3468:
3459:
3450:
3441:
3439:
3429:
3414:
3413:
3408:
3404:
3398:
3394:
3384:
3381:
3380:
3374:
3370:
3368:
3363:
3359:
3356:
3351:
3342:
3340:
3336:
3332:
3328:
3324:
3323:Hubble radius
3320:
3315:
3311:
3307:
3302:
3300:
3296:
3292:
3289:
3285:
3281:
3277:
3267:
3264:
3263:vacuum energy
3259:
3257:
3253:
3249:
3245:
3244:FLRW geometry
3240:
3238:
3234:
3229:
3228:superclusters
3225:
3221:
3217:
3213:
3209:
3204:
3201:
3193:
3189:
3180:
3178:
3174:
3170:
3166:
3156:
3152:
3148:
3145:
3141:
3137:
3133:
3128:
3124:
3120:
3116:
3115:compact space
3112:
3108:
3107:
3102:
3101:
3096:
3093:The ultimate
3091:
3089:
3085:
3081:
3077:
3073:
3069:
3059:
3057:
3052:
3047:
3045:
3041:
3037:
3033:
3029:
3025:
3021:
3017:
3012:
3010:
3006:
3002:
2997:
2995:
2990:
2985:
2981:
2976:
2972:
2967:
2965:
2961:
2956:
2953:
2948:
2946:
2942:
2938:
2934:
2929:
2927:
2923:
2912:
2908:
2904:
2900:
2896:
2889:
2878:
2863:
2860:
2845:
2842:
2834:
2823:
2820:
2816:
2813:
2809:
2806:
2802:
2799:
2795:
2792: –
2791:
2787:
2786:Find sources:
2780:
2776:
2770:
2769:
2764:This section
2762:
2758:
2753:
2752:
2743:
2740:
2732:
2722:
2718:
2712:
2711:
2706:This section
2704:
2695:
2694:
2689:
2687:
2680:
2679:
2674:
2673:
2668:
2663:
2654:
2653:
2640:
2638:
2634:
2628:
2626:
2622:
2618:
2613:
2611:
2596:
2592:
2588:
2584:
2579:
2577:
2571:
2569:
2548:
2544:
2540:
2536:
2532:
2528:
2519:
2514:
2505:
2500:
2490:
2488:
2484:
2466:
2462:
2458:
2454:
2450:
2447:
2438:
2434:
2424:
2422:
2418:
2414:
2404:
2402:
2397:
2395:
2391:
2387:
2383:
2379:
2375:
2371:
2367:
2363:
2357:
2353:
2339:
2334:
2325:
2323:
2307:
2304:
2301:
2298:
2278:
2275:
2272:
2269:
2249:
2245:
2241:
2238:
2235:
2215:
2212:
2209:
2186:
2178:
2175:
2172:
2166:
2163:
2159:
2155:
2152:
2145:
2144:
2143:
2141:
2125:
2105:
2085:
2082:
2079:
2076:
2068:
2067:perfect fluid
2063:
2061:
2043:
2040:
2036:
2032:
2029:
2020:
2018:
2002:
1980:
1977:
1973:
1969:
1966:
1951:
1935:
1932:
1928:
1924:
1921:
1899:
1896:
1892:
1888:
1885:
1877:
1873:
1869:
1859:
1857:
1853:
1849:
1844:
1842:
1838:
1833:
1818:
1816:
1811:
1807:
1802:
1800:
1794:
1792:
1788:
1781:
1771:
1768:
1764:
1760:
1759:time dilation
1756:
1752:
1748:
1741:
1731:
1729:
1725:
1721:
1717:
1711:
1696:
1693:
1679:
1675:
1669:
1665:
1661:
1658:
1655:
1647:
1643:
1625:
1621:
1617:
1614:
1606:
1593:
1590:
1574:
1570:
1564:
1560:
1556:
1553:
1550:
1547:
1527:
1524:
1518:
1515:
1484:
1468:
1460:
1444:
1436:
1420:
1412:
1396:
1373:
1368:
1362:
1358:
1348:
1344:
1336:
1332:
1327:
1324:
1318:
1315:
1311:
1305:
1301:
1298:
1295:
1289:
1286:
1281:
1276:
1273:
1262:
1261:
1260:
1258:
1254:
1238:
1229:
1227:
1210:
1190:
1187:
1184:
1164:
1156:
1151:
1149:
1145:
1141:
1137:
1129:
1124:
1115:
1113:
1097:
1077:
1054:
1045:
1039:
1036:
1027:
1017:
1016:
1015:
1014:according to
995:
966:
955:
951:
947:
943:
933:
923:
922:
917:
913:
912:David Spergel
901:
897:
885:
881:
877:
873:
870:
866:
854:
851:, offering a
850:
849:Virgo Cluster
846:
842:
838:
833:
830:
824:
820:
816:
811:
809:
805:
801:
797:
792:
789:
788:Knut Lundmark
784:
782:
778:
774:
770:
766:
765:Vesto Slipher
756:
754:
750:
746:
742:
734:
730:
726:
718:
714:
710:
707:, during the
706:
703:According to
701:
699:
695:
691:
687:
683:
682:metric tensor
680:
676:
672:
667:
665:
662:
658:
654:
650:
646:
642:
639:parts of the
638:
634:
630:
618:
613:
611:
606:
604:
599:
598:
596:
595:
590:
580:
578:
569:
568:
567:
566:
559:
556:
554:
551:
548:
542:
541:
538:
533:
532:
525:
522:
521:
517:
514:
512:
509:
507:
504:
502:
499:
497:
494:
492:
489:
487:
484:
482:
479:
477:
474:
472:
469:
467:
464:
462:
459:
457:
454:
452:
449:
447:
444:
442:
439:
437:
434:
432:
429:
427:
424:
422:
419:
417:
414:
412:
409:
407:
404:
402:
399:
397:
394:
392:
389:
387:
384:
382:
379:
377:
374:
372:
369:
368:
361:
360:
352:
346:
344:
341:
339:
336:
334:
331:
329:
326:
324:
321:
319:
316:
314:
311:
310:
307:
302:
301:
290:
287:
283:
280:
278:
275:
273:
270:
268:
265:
261:
258:
256:
253:
252:
251:
250:
246:
245:
240:
237:
233:
230:
228:
225:
224:
223:
222:
218:
217:
211:
205:
204:
197:
194:
192:
189:
187:
184:
182:
179:
175:
172:
170:
167:
165:
162:
158:
155:
154:
150:
144:
143:
132:
129:
125:
122:
120:
117:
116:
115:
114:
110:
109:
104:
101:
97:
94:
93:
92:
91:
83:
82:
77:
74:
72:
69:
67:
64:
60:
57:
56:
55:
54:
50:
46:
45:
42:
39:
38:
34:
33:
30:
19:
5168:Solar System
5085:
5009:Reionization
4968:Quintessence
4905:
4901:Hubble's law
4669:
4656:
4645:
4638:
4608:
4581:
4577:
4571:
4528:
4524:
4518:
4491:
4487:
4481:
4430:
4426:
4420:
4377:
4373:
4367:
4355:. Retrieved
4351:the original
4340:
4315:
4307:
4295:. Retrieved
4291:
4281:
4257:
4247:
4226:
4175:
4169:
4163:
4151:. Retrieved
4145:
4135:
4092:
4088:
4082:
4070:. Retrieved
4066:
4057:
4012:
4008:
3997:
3988:
3979:
3936:
3932:
3922:
3879:
3873:
3863:
3837:. Retrieved
3832:
3822:
3797:
3793:
3783:
3771:. Retrieved
3767:the original
3762:
3752:
3744:
3739:
3731:
3718:
3707:
3698:
3681:
3677:
3667:
3616:
3612:
3602:
3569:
3563:
3531:
3525:
3519:
3505:
3491:(8): 56–57.
3488:
3482:
3476:
3467:
3458:
3449:
3428:
3416:. Retrieved
3410:
3397:
3371:
3364:
3360:
3352:
3348:
3303:
3273:
3260:
3251:
3241:
3215:
3205:
3202:
3198:
3186:
3162:
3153:
3149:
3104:
3100:a posteriori
3098:
3097:of space is
3092:
3065:
3050:
3048:
3043:
3039:
3035:
3031:
3027:
3023:
3019:
3013:
3008:
2998:
2994:pseudosphere
2968:
2957:
2949:
2930:
2925:
2919:
2855:
2837:
2828:
2818:
2811:
2804:
2797:
2785:
2773:Please help
2768:verification
2765:
2735:
2726:
2707:
2683:
2676:
2670:
2669:Please help
2666:
2629:
2614:
2594:
2580:
2572:
2546:
2523:
2502:
2430:
2427:Matter epoch
2416:
2410:
2401:scale factor
2398:
2370:false vacuum
2359:
2201:
2064:
2021:
2017:scale factor
1957:
1865:
1845:
1841:scale factor
1830:An object's
1829:
1803:
1795:
1783:
1766:
1755:hyperboloids
1743:
1713:
1694:
1388:
1230:
1155:scale factor
1152:
1133:
1069:
954:Hubble's law
939:
919:
834:
815:Walter Baade
812:
804:Edwin Hubble
793:
785:
762:
702:
668:
628:
626:
351:Probe (WMAP)
285:
282:Reionization
263:
235:
209:
177:
168:
160:
157:Hubble's law
148:
127:
99:
62:
29:
5156:Spaceflight
5028:Experiments
4963:Dark matter
4953:Dark energy
4891:FLRW metric
4380:(11): 105.
3773:19 November
3418:21 February
3331:light-years
3327:gigaparsecs
3224:Hubble Flow
3220:Local Group
2964:such models
2903:light years
2729:August 2015
2518:blueshifted
2499:Dark energy
2493:Dark energy
1862:Temperature
1837:Hubble flow
1728:FLRW metric
1724:Hubble flow
1253:FLRW metric
1144:dark energy
1112:cosmic time
942:homogeneous
910:. In 2003,
872:light-curve
869:visual-band
813:Astronomer
745:dark energy
733:light-years
690:coordinates
306:Experiments
239:Dark matter
232:Dark energy
174:FLRW metric
111:Backgrounds
5178:Categories
4958:Dark fluid
4946:Components
4815:History of
4779:Background
4387:2011.01216
4238:1907.04495
4185:1712.06531
4153:22 October
4102:1807.06209
4022:1604.01424
3747:. pp. 5–16
3724:Messier 32
3389:References
3288:Einstein's
3169:black hole
3123:worldlines
3056:integrated
3030:in a time
2801:newspapers
2672:improve it
2376:, such as
1646:photon gas
1142:, such as
876:luminosity
865:Adam Riess
769:redshifted
386:Copernicus
364:Scientists
219:Components
5132:Astronomy
5045:BOOMERanG
4870:Inflation
4772:Cosmology
4620:0809.4573
4591:0810.0153
4584:: 20–30.
4538:0808.1081
4465:1323-3580
4412:226236696
4127:119335614
4049:118630031
4015:(1): 56.
3914:118938423
3709:Space.com
3684:: 49–59.
3643:1476-4687
3626:1212.1359
3594:122950995
3556:125190902
3138:, though
3111:connected
3001:worldline
2952:spacetime
2678:talk page
2451:∝
2433:redshifts
2417:radiation
2305:−
2276:−
2164:−
2156:∝
2153:ρ
2106:ρ
2086:ρ
2041:−
2033:∝
2030:ρ
1978:−
1970:∝
1967:ρ
1933:−
1925:∝
1897:−
1889:∝
1716:structure
1662:ρ
1618:ρ
1615:≪
1557:ρ
1554:−
1519:¨
1493:Λ
1421:ρ
1355:Λ
1316:ρ
1299:π
1290:−
1277:¨
1136:inflation
1049:→
1031:→
999:→
970:→
946:isotropic
794:In 1927,
779:used the
737:10 m
721:10 m
717:nanometer
679:spacetime
645:intrinsic
516:Zeldovich
416:Friedmann
391:de Sitter
318:BOOMERanG
247:Structure
212:Structure
96:Inflation
5189:Big Bang
4916:Redshift
4801:Universe
4791:Big Bang
4720:Archived
4687:Archived
4473:13068122
4357:28 April
4255:(2012).
4218:52987203
4210:30333628
4147:Phys.org
3971:10794058
3849:cite web
3659:47038783
3651:23060180
3377:See also
3353:In the "
3235:or the "
3106:a priori
3095:topology
3084:manifold
3080:universe
3072:universe
2831:May 2021
2625:GW170817
2485:and the
2483:galaxies
2384:and the
2362:inflaton
2356:inflaton
2338:Big Bang
2098:, where
1995:, where
1459:pressure
725:molecule
719:across (
713:Big Bang
635:between
633:distance
577:Category
496:Suntzeff
456:Lemaître
406:Einstein
371:Aaronson
164:Redshift
66:Universe
59:Big Bang
5120:Physics
5106:Portals
4596:Bibcode
4563:1365918
4543:Bibcode
4506:Bibcode
4494:: 174.
4445:Bibcode
4392:Bibcode
4297:17 June
4190:Bibcode
4107:Bibcode
4072:17 June
4027:Bibcode
3951:Bibcode
3894:Bibcode
3882:: L17.
3839:17 June
3802:Bibcode
3745:PASP 68
3732:ApJ 100
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