3352:, 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.
3277:
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.
3162:
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.
5126:
3049:, 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
2899:
3380:, 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.
2888:
1134:
2344:
572:
2524:
49:
2768:
5162:
2669:
5174:
5138:
5100:
584:
3203:
2710:
3018:. 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,
5150:
3233:, 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 "
3360:
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
3157:
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
1807:
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
3368:
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 –
3210:
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
2641:
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,
801:
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
3327:
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
3161:
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
3276:
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
3383:
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
3064:
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
2514:
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.
3002:
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
2535:
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
1149:), 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
3372:
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.
2351:
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
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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
2988:
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
2584:
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
4013:
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
3165:
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
1239:. 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.
3198:
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.
3057:. 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.
1854:. 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.
4357:
1969:
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
1795:
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
3037:; 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
2965:
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."
1823:
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
3101:, 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.
2997:
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
1845:
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
1234:
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
3140:
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
1780:
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).
2950:
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
1276:
767:, around 13.8 billion years ago, the universe expanded faster than the speed of light for a fraction of a second. Over intervals of time, the universe's expansion has driven the obscure force of
4361:
3214:
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.
4298:
4901:
3060:
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
674:
173:
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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
2414:
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).
2208:
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
1076:
3153:
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
2067:
2004:
1596:
2548:. 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
1649:
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
2490:
2422:
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
1549:
1959:
1923:
1865:. 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
1701:
4834:
3376:
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
544:
1023:
994:
4844:
4436:
Davis, Tamara M.; Lineweaver, Charles H. (2004). "Expanding
Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe".
2107:
1514:
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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
2271:
2127:
1442:
644:
2300:
2434:
at about 1 second. During radiation domination, cosmic expansion decelerated, with the scale factor growing proportionally with the square root of the time.
2237:
1212:
1737:
of the expanding universe, with no other motion, then it remains stationary in comoving coordinates. The comoving coordinates are the spatial coordinates in the
2147:
2024:
1490:
1466:
1418:
1260:
1232:
1186:
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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
1703:. Negative-pressure fluids, like dark energy, are not experimentally confirmed, but the existence of dark energy is inferred from astronomical observations.
614:
1188:, 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
3253:
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
967:, in which objects recede from each observer with velocities proportional to their positions with respect to that observer. That is, recession velocities
4773:
2993:
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
2785:
2682:
3348:. Visibility of these objects depends on the exact expansion history of the universe. Light that is emitted today from galaxies beyond the more-distant
3093:', sometimes used interchangeably, have distinct meanings in this context. Here 'space' is a mathematical concept that stands for the three-dimensional
4179:
Chen, Hsin-Yu; Fishbach, Maya; Holz, Daniel E. (17 October 2018). "A two per cent Hubble constant measurement from standard sirens within five years".
2492:). Also, gravitational structure formation is most efficient when nonrelativistic matter dominates, and this epoch is responsible for the formation of
1850:
of the expanding universe. The peculiar velocities of nonrelativistic particles decay as the universe expands, in inverse proportion with the cosmic
697:
5209:
3114:– 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
4242:
Bolejko, Krzysztof; Wang, Chengyi; Lewis, Geraint F. (2019). "Direct detection of the cosmic expansion: The redshift drift and the flux drift".
2581:
of distance from the observer, recessional velocity of objects at that distance increases by about 73 kilometres per second (160,000 mph).
4921:
2391:, because the rapid expansion would have diluted such relics. It was subsequently realized that the accelerated expansion would also solve the
1877:
The universe cools as it expands. This follows from the decay of particles' peculiar momenta, as discussed above. It can also be understood as
740:
5125:
2969:
In part to accommodate such different geometries, the expansion of the universe is inherently general-relativistic. It cannot be modeled with
2371:
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
2497:
1726:
905:. Reiss's measurements on the recession velocity of the nearby Virgo Cluster more closely agree with subsequent and independent analyses of
5085:
2921:
2720:
2403:
during inflation would have created initial variations in the density of the universe, which gravity later amplified to yield the observed
931:
348:
3206:
Animation of an expanding raisin-bread model. As the bread doubles in width (depth and length), the distances between raisins also double.
3014:
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
2731:
3769:
5014:
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all intents and purposes, it is safe to assume that the universe is infinite in spatial extent, without edge or strange connectedness.
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681:
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of both relativistic and nonrelativistic particles decay in inverse proportion with the scale factor. For photons, this leads to the
1141:, for a matter-dominated universe. The "acceleration" curve shows the trajectory of the scale factor for a universe with dark energy.
4849:
4340:
4281:
3685:"Un Univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extra-galactiques"
2955:
2869:
2851:
2749:
2696:
1137:
The expansion history depends on the density of the universe. Ω on this graph corresponds to the ratio of the matter density to the
557:
3687:[A homogeneous universe of constant mass and increasing radius accounting for the radial speed of extra-galactic nebulae].
4730:
850:, allowing for sharper images and, consequently, more accurate analyses of its observations. Shortly after the repairs were made,
3272:
The situation changes somewhat with the introduction of dark energy or a cosmological constant. A cosmological constant due to a
2811:
1820:
833:
607:
809:
independently reached a similar conclusion to
Friedmann on a theoretical basis, and also presented observational evidence for a
4942:
3033:
valid in small regions of spacetime that are approximately flat. In particular, light always travels locally at the speed
190:
4739:
2527:
When an object is receding, its light gets stretched (redshifted). When the object is approaching, its light gets compressed (
5204:
5004:
4839:
4766:
2789:
2688:
1390:{\displaystyle {\frac {\ddot {a}}{a}}=-{\frac {4\pi G}{3}}\left(\rho +{\frac {3p}{c^{2}}}\right)+{\frac {\Lambda c^{2}}{3}},}
1157:
and inflation, exert gravitational repulsion in the cosmological context, which accelerates the expansion of the universe. A
552:
266:
3417:
2818:
4947:
4875:
3393:
2515:
Similarly to inflation, dark energy drives accelerated expansion, such that the scale factor grows exponentially in time.
2150:
195:
118:
5116:
1925:). The temperature of nonrelativistic matter drops more sharply, scaling as the inverse square of the scale factor (i.e.
3865:
3714:
3361:
universe can alternatively be thought of as corresponding only to the inertial motion of objects away from one another.
3301:
3065:
behavior originates from a special property of metric expansion, but rather from local principles of special relativity
2977:
exist, they may be at fundamental odds with the observed interaction between matter and spacetime seen in the universe.
2596:, another possibility is to infer the present-day expansion rate from the sizes of the largest fluctuations seen in the
636:
2069:. This is because in addition to the volume dilution of the particle count, the energy of each particle (including the
836:
in Rome. For most of the second half of the 20th century, the value of the Hubble constant was estimated to be between
5194:
4865:
3494:
2800:
2597:
1886:
926:
600:
576:
123:
3261:, which ignores the effects of gravity. In particular, general relativity predicts that light will move at the speed
3053:, whereas the latter distance (shown by the orange line) is about 28 billion light-years, much larger than
5060:
5045:
4870:
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3257:, the same geometry that describes the expansion of the universe as a whole and was also the basis for the simpler
342:
322:
130:
75:
2778:
4759:
3885:
3537:
3116:
3110:
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over most of its history, showing how a light ray (red line) can travel an effective distance of 28 billion
2647:
2638:), to measure the expansion rate. Such measurements do not yet have the precision to resolve the Hubble tension.
3940:"First-Year Wilkinson Microwave Anisotropy Probe (WMAP)1 Observations: Determination of Cosmological Parameters"
1551:, and a positive pressure further decelerates expansion. On the other hand, sufficiently negative pressure with
5080:
4885:
3308:
had its origin (that is, matter in the universe is separating because it was separating in the past due to the
3143:
an observational question that is constrained as measurable or non-measurable by the universe's global geometry
2951:
2411:
2159:
1165:
791:
783:
337:
102:
4663:
2600:. A higher expansion rate would imply a smaller characteristic size of CMB fluctuations, and vice versa. The
1031:
5070:
4267:
2898:
2589:, supernova observations were used to determine that cosmic expansion is accelerating in the present epoch.
305:
185:
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3183:
3146:
3121:
2643:
2586:
2549:
2537:
2384:
1815:
Within the study of the evolution of structure within the universe, a natural scale emerges, known as the
1421:
960:
847:
846:
On 13 January 1994, NASA formally announced a completion of its repairs related to the main mirror of the
818:
4587:
Baryshev, Yu. V. (2008). "Expanding Space: The Root of
Conceptual Problems of the Cosmological Physics".
2273:. For an exotic fluid with negative pressure, like dark energy, the energy density drops more slowly; if
2036:
1973:
5024:
4880:
3316:
3294:
3142:
3026:
2994:
2724:
that states a
Knowledge (XXG) editor's personal feelings or presents an original argument about a topic.
2404:
2362:
1862:
1750:
1554:
1158:
1146:
1145:
The expansion of the universe can be understood as a consequence of an initial impulse (possibly due to
952:
748:
704:
689:
660:
510:
312:
254:
4497:
Whiting, Alan B. (2004). "The
Expansion of Space: Free Particle Motion and the Cosmological Redshift".
3178:
when very young and during part of its early expansion – far denser than is usually required to form a
2825:
1733:, which are defined to grow proportionally with the scale factor. If an object is moving only with the
1608:
4152:
2619:. There is a disagreement between this measurement and the supernova-based measurements, known as the
2454:
1519:
5055:
4745:
4606:
4553:
4516:
4455:
4402:
4200:
4117:
4037:
3961:
3904:
3812:
3696:
3584:
3546:
3503:
3365:
3349:
3243:
3182:– the universe did not re-collapse into a black hole. This is because commonly used calculations for
3150:
2541:
1928:
1892:
1809:
1790:
1730:
1720:
523:
495:
317:
1662:
828:
recalculated the size of the known universe in the 1940s, doubling the previous calculation made by
5178:
5075:
5029:
4906:
4816:
4796:
4668:
3324:
2905:
2631:
2601:
2545:
2431:
2400:
1801:
1757:
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1236:
894:
806:
787:
640:
455:
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332:
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276:
180:
70:
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that intersect with themselves, ultimately the question as to whether we are in something like a "
5166:
5009:
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4596:
4569:
4543:
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4445:
4418:
4392:
4263:
4243:
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4190:
4133:
4107:
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3977:
3951:
3920:
3894:
3665:
3631:
3600:
3562:
3422:
3377:
3369:
the ant's position over time will match the path of the red line on the embedding diagram above.
2970:
2961:"Geometrically flat" space has three dimensions and is consistent with Euclidean space. However,
2947:
2943:
2627:
2553:
2388:
1773:
1761:
708:
693:
685:
670:
536:
475:
445:
410:
380:
327:
271:
40:
4073:
1516:
is the cosmological constant. A positive energy density leads to deceleration of the expansion,
999:
970:
4273:
3145:. At present, observations are consistent with the universe having infinite extent and being a
677:(FLRW), where it corresponds to an increase in the scale of the spatial part of the universe's
5199:
5065:
5050:
4471:
4336:
4277:
4216:
3939:
3859:
3777:
3657:
3649:
3329:
2999:
2990:
2981:
2917:
2887:
2383:
state. Inflation was originally proposed to explain the absence of exotic relics predicted by
2083:
1882:
1878:
1842:
1825:
1652:
1499:
1138:
910:
890:
656:
505:
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4983:
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4208:
4181:
4125:
4121:
4045:
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3912:
3839:
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3592:
3554:
3218:
3154:
2909:
2593:
2396:
2070:
1797:
906:
879:
752:
588:
400:
390:
375:
226:
95:
4694:
3315:
While special relativity prohibits objects from moving faster than light with respect to a
2242:
2112:
1427:
1133:
832:
in 1929. He announced this finding to considerable astonishment at the 1952 meeting of the
4999:
4734:
4701:
3332:, all done at constant local proper time. For example, galaxies that are farther than the
3320:
3298:
3247:
2932:
2392:
2376:
2276:
1599:
1598:
leads to accelerated expansion, and the cosmological constant also accelerates expansion.
863:
663:
515:
450:
435:
420:
405:
395:
259:
4911:
3482:
Gibbons & Ellis, Classical and
Quantum Gravity 31 (2), 025003 (2014), arXiv:1308.1852
3305:
3129:
2216:
2033:
For ultrarelativistic particles ("radiation"), the energy density drops more sharply, as
1191:
964:
810:
652:
156:
4610:
4557:
4520:
4459:
4406:
4204:
4041:
3965:
3908:
3816:
3700:
3588:
3550:
3507:
2343:
5130:
4748:
at "Ask an
Astronomer" (the astronomer who provides this explanation is not specified).
4727:
4676:
3413:
3345:
3309:
3286:
3266:
3258:
2974:
2620:
2423:
2332:
2132:
2009:
1866:
1816:
1800:, and the region of the universe that lies within our particle horizon is known as the
1493:
1475:
1451:
1445:
1403:
1245:
1217:
1171:
1104:
1084:
935:
satellite (WMAP) further agreed with the estimated expansion rates for local galaxies,
851:
500:
460:
4534:
Bunn, E. F.; Hogg, D. W. (2009). "The kinematic origin of the cosmological redshift".
5188:
4721:
4422:
4325:
4137:
4059:
4050:
4015:
3924:
3604:
3566:
3521:
3473:
Tipler, Monthly Notices of the Royal Astronomical Society 282(1), pp. 206–210 (1996).
3333:
3273:
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922:
859:
798:
775:
632:
485:
470:
370:
17:
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3981:
3800:
3684:
3669:
3455:
Bunn & Hogg, American Journal of Physics 77, pp. 688–694 (2009), arXiv:0808.1081
3265:
with respect to the local motion of the exploding matter, a phenomenon analogous to
3217:
Once objects are bound by gravity, they no longer recede from each other. Thus, the
5154:
5019:
4573:
3238:
3004:
2380:
2027:
1851:
829:
825:
817:
observationally confirmed Lundmark's and Lemaître's findings in 1929. Assuming the
814:
490:
465:
440:
425:
281:
4129:
4098:
Collaboration, Planck (2020). "Planck 2018 results. VI. Cosmological parameters".
2523:
4383:
Pons, J. M.; Talavera, P. (2021). "On cosmological expansion and local physics".
4973:
4963:
3289:'s inflationary period, all the matter and energy in the universe was set on an
3254:
3234:
3230:
2767:
2509:
1847:
1765:
1738:
1734:
1263:
1154:
1122:
882:
855:
821:, these findings would imply that all galaxies are moving away from each other.
768:
744:
732:
648:
238:
231:
4707:
4414:
3846:. 813 Santa Barbara Street, Pasadena, California 91101.: Carnegie Observatories
2958:. Euclidean "geometrically flat" space has a Riemann curvature tensor of zero.
811:
linear relationship between distance to galaxies and their recessional velocity
4968:
4212:
3734:
3596:
3341:
3337:
3179:
2913:
1656:
886:
875:
480:
4475:
3881:""Using Type IA supernova light curve shapes to measure the Hubble constant""
3653:
4782:
3719:
3222:
3133:
3011:
2962:
2528:
956:
716:
678:
430:
4220:
3770:"Section 2: The Great Debate and the Great Mistake: Shapley, Hubble, Baade"
3661:
1729:
with the expansion of the universe factored out. This motivates the use of
1400:
shows how the contents of the universe influence its expansion rate. Here,
3619:
3328:
definition of distance used here is the summation or integration of local
3045:, as the red worldline illustrates. While it always moves locally at
963:. These constraints demand that any expansion of the universe accord with
666:
and does not limit the recession rates of cosmologically distant objects.
4926:
4811:
4801:
4511:
4450:
4157:
3956:
3899:
3105:
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3090:
3082:
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2443:
2372:
2366:
2348:
1858:
1469:
779:
764:
724:
712:
163:
65:
58:
4153:"Gravitational waves could soon provide measure of universe's expansion"
3250:", with which we would eventually merge if dark energy were not acting.
3202:
4003:
de Salas et al., Physical Review D. 92, 123534 (2015), arXiv:1511.00672
3738:
3558:
3290:
3175:
3137:
2985:
2792: in this section. Unsourced material may be challenged and removed.
2544:
is known. The object's distance can then be inferred from the observed
1725:
In an expanding universe, it is often useful to study the evolution of
4565:
3492:
Slipher, V. M. (1913). "The Radial Velocity of the Andromeda Nebula".
48:
3015:
2578:
2447:
2347:
A graphical representation of the expansion of the universe from the
1602:
839:
743:, and is still doing so. Physicists have postulated the existence of
4742:
from the University of Winnipeg: an illustration, but no explanation
4467:
3645:
3464:
Lewis, Australian Physics 53(3), pp. 95–100 (2016), arXiv:1605.08634
3190:, and do not apply to rapidly expanding space such as the Big Bang.
3186:
are usually based upon objects of relatively constant size, such as
2984:
that show the large-scale geometry of the universe according to the
5149:
4728:
Hubble Tutorial from the University of Wisconsin Physics Department
4397:
4248:
4195:
4112:
4032:
3994:
Allahverdi et al., Open J. Astrophys. 4, 1 (2021), arXiv:2006.16182
3973:
3916:
3880:
3824:
3754:
Baade, W. (1956) "The period–luminosity relation of the Cepheids".
1164:
Mathematically, the expansion of the universe is quantified by the
4630:
4601:
4548:
3636:
3201:
3086:
3078:
2522:
2342:
1132:
3237:" and end up as bound, non-expanding objects up to the scales of
2073:) also drops significantly due to the decay of peculiar momenta.
4717:
4713:
4016:"A 2.4% Determination of the Local Value of the Hubble Constant"
3187:
794:
to provide theoretical evidence that the universe is expanding.
653:
speeds that are proportional to their distance from the observer
4755:
2552:
and the redshifts of their host galaxies. More recently, using
3418:"Cosmos Controversy: The Universe Is Expanding, but How Fast?"
3344:, away from us have a recession speed that is faster than the
2761:
2703:
2662:
728:
4650:
The Expanding Universe: Astronomy's 'Great Debate', 1900–1931
4751:
4746:"Ant on a balloon" analogy to explain the expanding universe
2626:
A third option proposed recently is to use information from
27:
Increase in distance between parts of the universe over time
3029:
of general relativity, the rules of special relativity are
2721:
personal reflection, personal essay, or argumentative essay
3715:"Astronomer sleuth solves mystery of Big Cosmos discovery"
786:
interpreted as galaxies receding from the Earth. In 1922,
2931:
At cosmological scales, the present universe conforms to
4624:
Peacock, J. A. (2008). "A diatribe on expanding space".
1214:
at the present time. Because the universe is expanding,
4652:. Press Syndicate of the University of Cambridge, 1933.
3003:
similar effect can be seen in the tubular shape of the
2727:
1237:
this time at 13.787 ± 0.020 billion years ago
854:'s 1994 Key Project analyzed the recession velocity of
5114:
4438:
Publications of the Astronomical Society of Australia
3535:
Friedman, A. (1922). "Ăśber die KrĂĽmmung des Raumes".
2642:
changes in redshift or flux could be observed by the
2457:
2308:
2279:
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2219:
2162:
2135:
2115:
2086:
2039:
2012:
1976:
1931:
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induced by the repulsive gravity of the dark energy.
1665:
1611:
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1502:
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1279:
1248:
1220:
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1087:
1034:
1002:
973:
951:
The universe at the largest scales is observed to be
651:(which are bound to each other by gravity) recede at
3840:"The HST Key Project to Measure the Hubble Constant"
3306:
precise and regular form of the universe's expansion
2604:
measured the expansion rate this way and determined
2446:
as the universe expands, eventually nonrelativistic
2335:, the energy density grows as the universe expands.
755:, this acceleration becomes dominant in the future.
5038:
4992:
4956:
4935:
4894:
4858:
4825:
4789:
3741:, and the central region of the Andromeda nebula".
3573:Friedmann, A. (1999). "On the Curvature of Space".
1885:fluids, often called "radiation" and including the
4324:
4299:"What Do You Mean, The Universe Is Flat? (Part I)"
3120:constraints) on how the space in which we live is
2484:
2323:
2294:
2265:
2231:
2202:
2141:
2121:
2101:
2061:
2018:
1998:
1953:
1917:
1695:
1643:
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1543:
1508:
1484:
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1436:
1412:
1389:
1254:
1226:
1206:
1180:
1113:
1093:
1070:
1017:
988:
959:(the same in all directions), consistent with the
4695:Answer to a question about the expanding universe
3451:
3449:
2916:(orange line) in just 13.8 billion years of
4657:Cosmological Inflation and Large-Scale Structure
3689:Annales de la Société Scientifique de Bruxelles
1889:, scales inversely with the scale factor (i.e.
802:was within 1% of the best measurements today."
778:discovered that light from remote galaxies was
659:, this limitation applies only with respect to
2153:. The energy density of such a fluid drops as
4767:
4662:Lineweaver, Charles H. and Davis, Tamara M. "
3128:. Though certain cosmological models such as
608:
8:
2654:Conceptual considerations and misconceptions
2540:, which is an object or event for which the
1266:, and its time evolution is governed by the
673:. It can be modeled mathematically with the
3944:The Astrophysical Journal Supplement Series
2697:Learn how and when to remove these messages
2592:By assuming a cosmological model, e.g. the
4774:
4760:
4752:
3124:or whether it wraps around on itself as a
2980:The images to the right show two views of
929:during the first year observations of the
675:Friedmann–Lemaître–Robertson–Walker metric
615:
601:
215:
89:
47:
31:
4845:Religious interpretations of the Big Bang
4629:
4600:
4547:
4510:
4449:
4396:
4247:
4194:
4111:
4049:
4031:
3955:
3898:
3635:
3229:us and is not expanding away. Within the
2870:Learn how and when to remove this message
2852:Learn how and when to remove this message
2750:Learn how and when to remove this message
2472:
2468:
2456:
2307:
2278:
2255:
2244:
2218:
2203:{\displaystyle \rho \propto a^{-3(1+w)}.}
2173:
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2134:
2114:
2085:
2050:
2038:
2011:
1987:
1975:
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1930:
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1004:
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996:scale with (observer-centered) positions
975:
974:
972:
4835:Discovery of cosmic microwave background
3323:, it does not apply to situations where
2556:, the expansion rate was measured to be
893:. This further minimized the systematic
688:description but rather only a choice of
655:, on average. While objects cannot move
5121:
3405:
2630:events (especially those involving the
1071:{\displaystyle {\vec {v}}=H{\vec {x}},}
913:, which estimates a Hubble constant of
246:
218:
110:
39:
4722:Explanation of the universal expansion
4358:"What is the universe expanding into?"
4331:. Princeton University Press. p.
3857:
2659:Measuring distances in expanding space
763:In the cosmic inflation period of the
4655:Liddle, Andrew R. and Lyth, David H.
3801:""The on-orbit performance of WFPC2""
3774:The Cepheid Distance Scale: A History
3522:"Vesto Slipher – American astronomer"
3356:Common analogies for cosmic expansion
3010:The brown line on the diagram is the
2498:large-scale structure of the universe
2405:spectrum of matter density variations
2129:is the energy density. The parameter
669:Cosmic expansion is a key feature of
7:
3733:Baade, W. (1944) "The resolution of
3620:"Who discovered Universe expansion?"
3384:expansion has a center and an edge.
3194:Effects of expansion on small scales
3170:Density of universe during expansion
2790:adding citations to reliable sources
2577:. This means that for every million
932:Wilkinson Microwave Anisotropy Probe
4683:. Princeton University Press, 1991.
4659:. Cambridge University Press, 2000.
4360:. Ask an Astronomer. Archived from
3281:Metric expansion and speed of light
2062:{\displaystyle \rho \propto a^{-4}}
1999:{\displaystyle \rho \propto a^{-3}}
1808:never reach us, because there is a
1710:Distances in the expanding universe
885:shapes to more finely estimate the
878:et al. used an empirical method of
4385:General Relativity and Gravitation
4151:Lerner, Louise (22 October 2018).
3576:General Relativity and Gravitation
3319:where spacetime can be treated as
1605:is essentially pressureless, with
1591:{\displaystyle p<-\rho c^{2}/3}
1503:
1365:
1101:quantifies the rate of expansion.
343:2dF Galaxy Redshift Survey ("2dF")
25:
4850:Timeline of cosmological theories
4664:Misconceptions about the Big Bang
4356:Rothstein, Dave (23 April 2003).
4074:"The Nobel Prize in Physics 2011"
3938:Spergel, D. N. (September 2003).
2956:curvature of Riemannian manifolds
2678:This article has multiple issues.
2426:particles, conventionally called
1644:{\displaystyle |p|\ll \rho c^{2}}
1270:. The second Friedmann equation,
731:) to one approximately 10.6
558:Timeline of cosmological theories
323:Cosmic Background Explorer (COBE)
5172:
5160:
5148:
5136:
5124:
5098:
4672:, March 2005 (non-free content).
4327:Principles of Physical Cosmology
4303:Scientific American Blog Network
2939:, to within experimental error.
2935:, what cosmologists describe as
2897:
2886:
2766:
2708:
2667:
2485:{\displaystyle a\propto t^{2/3}}
2302:it remains constant in time. If
1832:Consequences of cosmic expansion
1826:Newtonian gravitational dynamics
1544:{\displaystyle {\ddot {a}}<0}
834:International Astronomical Union
582:
571:
570:
4943:Future of an expanding universe
3879:Riess, Adam G. (January 1995).
3443:Peacock (2008), arXiv:0809.4573
2777:needs additional citations for
2686:or discuss these issues on the
1954:{\displaystyle T\propto a^{-2}}
1918:{\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
5210:Physical cosmological concepts
4840:History of the Big Bang theory
2192:
2180:
2076:In general, we can consider a
1696:{\displaystyle p=\rho c^{2}/3}
1621:
1613:
1059:
1041:
1009:
980:
553:History of the Big Bang theory
349:Wilkinson Microwave Anisotropy
1:
4948:Ultimate fate of the universe
4876:Gravitational wave background
3805:Astrophysical Journal Letters
3394:Comoving and proper distances
2410:During inflation, the cosmic
1857:More generally, the peculiar
947:Structure of cosmic expansion
545:Discovery of cosmic microwave
196:Ultimate fate of the universe
4100:Astronomy & Astrophysics
3302:general theory of relativity
2519:Measuring the expansion rate
1760:. In a universe governed by
1129:Dynamics of cosmic expansion
723:, about half the width of a
4866:Cosmic microwave background
4536:American Journal of Physics
4130:10.1051/0004-6361/201833910
3618:Steer, Ian (October 2012).
3495:Lowell Observatory Bulletin
3073:Topology of expanding space
2942:Consequently, the rules of
2801:"Expansion of the universe"
2598:cosmic microwave background
2379:that has a positive-energy
2213:Nonrelativistic matter has
2151:equation of state parameter
1887:cosmic microwave background
927:cosmic microwave background
897:of the Hubble constant, to
313:Black Hole Initiative (BHI)
5226:
4871:Cosmic neutrino background
4807:Chronology of the universe
4415:10.1007/s10714-021-02874-4
4323:Peebles, P. J. E. (1993).
4051:10.3847/0004-637X/826/1/56
3683:Lemaître, Georges (1927).
3350:cosmological event horizon
2507:
2360:
1821:Cosmological perturbations
1788:
1748:
1718:
1018:{\displaystyle {\vec {x}}}
989:{\displaystyle {\vec {v}}}
955:(the same everywhere) and
696:, it is also predicted by
76:Chronology of the universe
5094:
4917:Expansion of the universe
4724:" at an elementary level.
4213:10.1038/s41586-018-0606-0
4020:The Astrophysical Journal
3886:The Astrophysical Journal
3336:, approximately 4.5
3085:is expanding. The words '
2648:Extremely Large Telescope
1764:, such surfaces would be
629:expansion of the universe
169:Expansion of the universe
3864:: CS1 maint: location (
3221:, which is bound to the
3174:Despite being extremely
2952:Riemann curvature tensor
2948:Euclid's fifth postulate
2102:{\displaystyle p=w\rho }
1837:Velocities and redshifts
1659:) has positive pressure
1509:{\displaystyle \Lambda }
792:Einstein field equations
333:Planck space observatory
119:Gravitational wave (GWB)
5071:Observational cosmology
4700:11 January 2009 at the
4269:A Universe from Nothing
4122:2020A&A...641A...6P
3799:Trauger, J. T. (1994).
3597:10.1023/A:1026751225741
3069:over a curved surface.
2632:merger of neutron stars
2324:{\displaystyle w<-1}
1768:, because relativistic
874:. Later the same year,
637:gravitationally unbound
186:Inhomogeneous cosmology
4922:Accelerating expansion
4740:Expanding raisin bread
4708:The Expanding universe
4297:Castelvecchi, Davide.
4272:. Free Press. p.
3538:Zeitschrift fĂĽr Physik
3225:, is actually falling
3207:
3184:gravitational collapse
3147:simply connected space
2995:accelerating expansion
2730:by rewriting it in an
2644:Square Kilometre Array
2587:Nobel Prize in Physics
2550:Cepheid variable stars
2532:
2486:
2385:grand unified theories
2353:
2325:
2296:
2267:
2233:
2204:
2143:
2123:
2103:
2063:
2020:
2000:
1955:
1919:
1697:
1645:
1592:
1545:
1510:
1486:
1462:
1438:
1422:gravitational constant
1414:
1391:
1262:is a parameter of the
1256:
1228:
1208:
1182:
1161:also has this effect.
1142:
1115:
1095:
1081:where the Hubble rate
1072:
1019:
990:
961:cosmological principle
848:Hubble Space Telescope
819:cosmological principle
5205:Concepts in astronomy
5025:Shape of the universe
5015:Large-scale structure
4828:cosmological theories
3340:or 14.7 billion
3317:local reference frame
3295:equivalence principle
3205:
3151:cosmological horizons
3027:equivalence principle
2526:
2487:
2363:inflation (cosmology)
2346:
2326:
2297:
2268:
2266:{\displaystyle w=1/3}
2234:
2205:
2144:
2124:
2122:{\displaystyle \rho }
2104:
2064:
2021:
2001:
1956:
1920:
1881:. The temperature of
1863:cosmological redshift
1785:Cosmological horizons
1776:, the shape of these
1751:Shape of the universe
1745:Shape of the universe
1698:
1655:particles (such as a
1646:
1593:
1546:
1511:
1487:
1463:
1448:within the universe,
1439:
1437:{\displaystyle \rho }
1415:
1392:
1257:
1229:
1209:
1183:
1159:cosmological constant
1136:
1116:
1096:
1073:
1020:
991:
858:from the core of the
749:cosmological constant
277:Large-scale structure
255:Shape of the universe
18:Expansion of universe
5105:astronomy portal
3416:(20 February 2017).
3366:ant on a rubber rope
3293:consistent with the
3244:Shapley Supercluster
3132:even permit bizarre
2922:Mathematical details
2786:improve this article
2602:Planck collaboration
2575:1.74 (km/s)/Mpc
2542:intrinsic brightness
2455:
2401:quantum fluctuations
2306:
2295:{\displaystyle w=-1}
2277:
2243:
2239:while radiation has
2217:
2160:
2133:
2113:
2084:
2037:
2010:
1974:
1929:
1893:
1810:cosmic event horizon
1791:Cosmological horizon
1778:comoving synchronous
1731:comoving coordinates
1721:Comoving coordinates
1715:Comoving coordinates
1663:
1609:
1555:
1520:
1500:
1476:
1452:
1428:
1404:
1277:
1246:
1218:
1192:
1172:
1105:
1085:
1032:
1000:
971:
838:50 and 90 kmâ‹…sâ‹…
649:the nearest galaxies
643:with time. It is an
589:Astronomy portal
547:background radiation
524:List of cosmologists
5030:Structure formation
4993:Structure formation
4907:Friedmann equations
4817:Observable universe
4797:Age of the universe
4733:9 June 2014 at the
4669:Scientific American
4648:Eddington, Arthur.
4611:2008pc2..conf...20B
4589:Practical Cosmology
4558:2009AmJPh..77..688B
4521:2004Obs...124..174W
4460:2004PASA...21...97D
4407:2021GReGr..53..105P
4264:Krauss, Lawrence M.
4205:2018Natur.562..545C
4042:2016ApJ...826...56R
3966:2003ApJS..148..175S
3909:1995ApJ...438L..17R
3817:1994ApJ...435L...3T
3780:on 10 December 2007
3723:. 14 November 2011.
3701:1927ASSB...47...49L
3589:1999GReGr..31.1991F
3551:1922ZPhy...10..377F
3508:1913LowOB...2...56S
3325:spacetime curvature
3321:flat and unchanging
3304:. This is when the
3291:inertial trajectory
2906:isometric embedding
2617:0.5 (km/s)/Mpc
2546:apparent brightness
2432:neutrino decoupling
2331:, corresponding to
2232:{\displaystyle w=0}
1802:observable universe
1758:age of the universe
1268:Friedmann equations
1207:{\displaystyle a=1}
1151:relativistic fluids
925:'s analysis of the
797:Swedish astronomer
788: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
5195:General relativity
5010:Large quasar group
4675:Mook, Delo E. and
4643:Printed references
3559:10.1007/BF01332580
3423:The New York Times
3378:Gaussian curvature
3330:comoving distances
3285:At the end of the
3208:
3155:inflationary model
3081:that makes up the
2982:spacetime diagrams
2971:special relativity
2944:Euclidean geometry
2937:geometrically flat
2732:encyclopedic style
2719:is written like a
2650:in the mid-2030s.
2628:gravitational wave
2554:Type Ia supernovae
2533:
2482:
2389:magnetic monopoles
2354:
2321:
2292:
2263:
2229:
2200:
2139:
2119:
2099:
2059:
2016:
1996:
1951:
1915:
1774:general relativity
1762:special relativity
1693:
1641:
1588:
1541:
1506:
1482:
1458:
1434:
1410:
1387:
1252:
1224:
1204:
1178:
1143:
1111:
1091:
1068:
1015:
986:
895:measurement errors
891:Type Ia supernovae
709:inflationary epoch
694:general relativity
671:Big Bang cosmology
328:Dark Energy Survey
272:Large quasar group
41:Physical cosmology
5112:
5111:
5066:Illustris project
4681:Inside Relativity
4566:10.1119/1.3129103
4189:(7728): 545–547.
3583:(12): 1991–2000.
3025:According to the
3000:comoving distance
2991:cosmological time
2918:cosmological time
2880:
2879:
2872:
2862:
2861:
2854:
2836:
2760:
2759:
2752:
2701:
2430:, by the time of
2339:Expansion history
2142:{\displaystyle w}
2019:{\displaystyle a}
1883:ultrarelativistic
1879:adiabatic cooling
1843:peculiar velocity
1653:ultrarelativistic
1651:, while a gas of
1532:
1485:{\displaystyle c}
1461:{\displaystyle p}
1413:{\displaystyle G}
1382:
1352:
1319:
1295:
1290:
1255:{\displaystyle a}
1242:The scale factor
1227:{\displaystyle a}
1181:{\displaystyle a}
1121:is a function of
1114:{\displaystyle H}
1094:{\displaystyle H}
1062:
1044:
1012:
983:
911:Type Ia supernova
747:, appearing as a
698:Newtonian gravity
657:faster than light
625:
624:
296:
295:
138:
137:
16:(Redirected from
5217:
5177:
5176:
5175:
5165:
5164:
5163:
5153:
5152:
5141:
5140:
5139:
5129:
5128:
5120:
5103:
5102:
5101:
5005:Galaxy formation
4984:Lambda-CDM model
4895:Present universe
4776:
4769:
4762:
4753:
4720:team offers an "
4636:
4635:
4633:
4621:
4615:
4614:
4604:
4584:
4578:
4577:
4551:
4531:
4525:
4524:
4514:
4512:astro-ph/0404095
4494:
4488:
4487:
4453:
4451:astro-ph/0310808
4433:
4427:
4426:
4400:
4380:
4374:
4373:
4371:
4369:
4353:
4347:
4346:
4330:
4320:
4314:
4313:
4311:
4309:
4294:
4288:
4287:
4260:
4254:
4253:
4251:
4239:
4233:
4232:
4198:
4176:
4170:
4169:
4167:
4165:
4148:
4142:
4141:
4115:
4095:
4089:
4088:
4086:
4084:
4070:
4064:
4063:
4053:
4035:
4010:
4004:
4001:
3995:
3992:
3986:
3985:
3959:
3957:astro-ph/0302209
3935:
3929:
3928:
3902:
3900:astro-ph/9410054
3876:
3870:
3869:
3863:
3855:
3853:
3851:
3838:Freedman, W. L.
3835:
3829:
3828:
3796:
3790:
3789:
3787:
3785:
3776:. Archived from
3765:
3759:
3752:
3746:
3731:
3725:
3724:
3711:
3705:
3704:
3680:
3674:
3673:
3639:
3615:
3609:
3608:
3570:
3532:
3526:
3525:
3518:
3512:
3511:
3489:
3483:
3480:
3474:
3471:
3465:
3462:
3456:
3453:
3444:
3441:
3435:
3434:
3432:
3430:
3410:
3223:Milky Way Galaxy
3219:Andromeda Galaxy
3130:Gödel's universe
2946:associated with
2910:visible universe
2904:Two views of an
2901:
2890:
2875:
2868:
2857:
2850:
2846:
2843:
2837:
2835:
2794:
2770:
2762:
2755:
2748:
2744:
2741:
2735:
2712:
2711:
2704:
2693:
2671:
2670:
2663:
2618:
2616:
2594:Lambda-CDM model
2576:
2574:
2569:
2565:
2491:
2489:
2488:
2483:
2481:
2480:
2476:
2442:Since radiation
2399:. Additionally,
2397:flatness problem
2357:Cosmic inflation
2330:
2328:
2327:
2322:
2301:
2299:
2298:
2293:
2272:
2270:
2269:
2264:
2259:
2238:
2236:
2235:
2230:
2209:
2207:
2206:
2201:
2196:
2195:
2148:
2146:
2145:
2140:
2128:
2126:
2125:
2120:
2108:
2106:
2105:
2100:
2071:rest mass energy
2068:
2066:
2065:
2060:
2058:
2057:
2025:
2023:
2022:
2017:
2005:
2003:
2002:
1997:
1995:
1994:
1960:
1958:
1957:
1952:
1950:
1949:
1924:
1922:
1921:
1916:
1914:
1913:
1798:particle horizon
1702:
1700:
1699:
1694:
1689:
1684:
1683:
1650:
1648:
1647:
1642:
1640:
1639:
1624:
1616:
1597:
1595:
1594:
1589:
1584:
1579:
1578:
1550:
1548:
1547:
1542:
1534:
1533:
1525:
1515:
1513:
1512:
1507:
1491:
1489:
1488:
1483:
1467:
1465:
1464:
1459:
1443:
1441:
1440:
1435:
1419:
1417:
1416:
1411:
1396:
1394:
1393:
1388:
1383:
1378:
1377:
1376:
1363:
1358:
1354:
1353:
1351:
1350:
1341:
1333:
1320:
1315:
1304:
1296:
1291:
1283:
1281:
1261:
1259:
1258:
1253:
1233:
1231:
1230:
1225:
1213:
1211:
1210:
1205:
1187:
1185:
1184:
1179:
1139:critical density
1120:
1118:
1117:
1112:
1100:
1098:
1097:
1092:
1077:
1075:
1074:
1069:
1064:
1063:
1055:
1046:
1045:
1037:
1024:
1022:
1021:
1016:
1014:
1013:
1005:
995:
993:
992:
987:
985:
984:
976:
942:
940:
920:
918:
909:calibrations of
907:Cepheid variable
904:
902:
873:
872:17 kmâ‹…sâ‹…Mpc
871:
842:
807: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:
208:Components
90:
51:
32:
21:
5225:
5224:
5220:
5219:
5218:
5216:
5215:
5214:
5185:
5184:
5183:
5173:
5171:
5161:
5159:
5147:
5137:
5135:
5123:
5115:
5113:
5108:
5099:
5097:
5090:
5034:
5000:Galaxy filament
4988:
4952:
4936:Future universe
4931:
4890:
4886:Nucleosynthesis
4854:
4827:
4821:
4785:
4780:
4735:Wayback Machine
4706:Felder, Gary, "
4702:Wayback Machine
4690:
4645:
4640:
4639:
4623:
4622:
4618:
4586:
4585:
4581:
4533:
4532:
4528:
4499:The Observatory
4496:
4495:
4491:
4468:10.1071/AS03040
4435:
4434:
4430:
4382:
4381:
4377:
4367:
4365:
4355:
4354:
4350:
4343:
4322:
4321:
4317:
4307:
4305:
4296:
4295:
4291:
4284:
4262:
4261:
4257:
4241:
4240:
4236:
4178:
4177:
4173:
4163:
4161:
4150:
4149:
4145:
4097:
4096:
4092:
4082:
4080:
4072:
4071:
4067:
4012:
4011:
4007:
4002:
3998:
3993:
3989:
3937:
3936:
3932:
3878:
3877:
3873:
3856:
3849:
3847:
3837:
3836:
3832:
3798:
3797:
3793:
3783:
3781:
3767:
3766:
3762:
3753:
3749:
3732:
3728:
3713:
3712:
3708:
3682:
3681:
3677:
3646:10.1038/490176c
3617:
3616:
3612:
3572:
3571:translated in
3534:
3533:
3529:
3520:
3519:
3515:
3491:
3490:
3486:
3481:
3477:
3472:
3468:
3463:
3459:
3454:
3447:
3442:
3438:
3428:
3426:
3414:Overbye, Dennis
3412:
3411:
3407:
3402:
3390:
3358:
3283:
3248:Great Attractor
3211:them to do so.
3196:
3172:
3099:various strings
3077:Over time, the
3075:
2933:Euclidean space
2929:
2928:
2927:
2926:
2925:
2908:of part of the
2902:
2893:
2892:
2891:
2876:
2865:
2864:
2863:
2858:
2847:
2841:
2838:
2795:
2793:
2783:
2771:
2756:
2745:
2739:
2736:
2728:help improve it
2725:
2713:
2709:
2672:
2668:
2661:
2656:
2614:
2612:
2610:
2572:
2570:
2567:
2563:
2562:
2538:standard candle
2521:
2512:
2506:
2464:
2453:
2452:
2440:
2420:
2418:Radiation epoch
2393:horizon problem
2369:
2361:Main articles:
2359:
2341:
2304:
2303:
2275:
2274:
2241:
2240:
2215:
2214:
2169:
2158:
2157:
2131:
2130:
2111:
2110:
2082:
2081:
2046:
2035:
2034:
2008:
2007:
1983:
1972:
1971:
1967:
1938:
1927:
1926:
1902:
1891:
1890:
1875:
1839:
1834:
1793:
1787:
1753:
1747:
1723:
1717:
1712:
1706:
1675:
1661:
1660:
1631:
1607:
1606:
1600:Nonrelativistic
1570:
1553:
1552:
1518:
1517:
1498:
1497:
1474:
1473:
1450:
1449:
1426:
1425:
1402:
1401:
1368:
1364:
1342:
1334:
1325:
1321:
1305:
1275:
1274:
1244:
1243:
1216:
1215:
1190:
1189:
1170:
1169:
1131:
1103:
1102:
1083:
1082:
1030:
1029:
998:
997:
969:
968:
949:
941:5 kmâ‹…sâ‹…Mpc
938:
936:
919:7 kmâ‹…sâ‹…Mpc
916:
914:
903:7 kmâ‹…sâ‹…Mpc
900:
898:
869:
867:
866:measurement of
864:Hubble constant
837:
782:, 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:
5223:
5221:
5213:
5212:
5207:
5202:
5197:
5187:
5186:
5182:
5181:
5169:
5157:
5145:
5133:
5110:
5109:
5095:
5092:
5091:
5089:
5088:
5083:
5078:
5073:
5068:
5063:
5058:
5053:
5048:
5042:
5040:
5036:
5035:
5033:
5032:
5027:
5022:
5017:
5012:
5007:
5002:
4996:
4994:
4990:
4989:
4987:
4986:
4981:
4976:
4971:
4966:
4960:
4958:
4954:
4953:
4951:
4950:
4945:
4939:
4937:
4933:
4932:
4930:
4929:
4924:
4919:
4914:
4909:
4904:
4898:
4896:
4892:
4891:
4889:
4888:
4883:
4878:
4873:
4868:
4862:
4860:
4856:
4855:
4853:
4852:
4847:
4842:
4837:
4831:
4829:
4823:
4822:
4820:
4819:
4814:
4809:
4804:
4799:
4793:
4791:
4787:
4786:
4781:
4779:
4778:
4771:
4764:
4756:
4750:
4749:
4743:
4737:
4725:
4711:
4704:
4693:Swenson, Jim,
4689:
4688:External links
4686:
4685:
4684:
4677:Thomas Vargish
4673:
4660:
4653:
4644:
4641:
4638:
4637:
4616:
4579:
4542:(8): 688–694.
4526:
4489:
4428:
4375:
4364:on 8 June 2020
4348:
4341:
4315:
4289:
4282:
4255:
4234:
4171:
4143:
4090:
4078:NobelPrize.org
4065:
4005:
3996:
3987:
3974:10.1086/377226
3950:(1): 175–194.
3930:
3917:10.1086/187704
3871:
3830:
3825:10.1086/187580
3791:
3760:
3747:
3726:
3706:
3675:
3610:
3545:(1): 377–386.
3527:
3513:
3484:
3475:
3466:
3457:
3445:
3436:
3404:
3403:
3401:
3398:
3397:
3396:
3389:
3386:
3357:
3354:
3346:speed of light
3310:inflaton field
3287:early universe
3282:
3279:
3267:frame dragging
3259:Milne universe
3195:
3192:
3171:
3168:
3074:
3071:
2973:alone: Though
2903:
2896:
2895:
2894:
2885:
2884:
2883:
2882:
2881:
2878:
2877:
2860:
2859:
2774:
2772:
2765:
2758:
2757:
2716:
2714:
2707:
2702:
2676:
2675:
2673:
2666:
2660:
2657:
2655:
2652:
2621:Hubble tension
2608:
2560:
2520:
2517:
2508:Main article:
2505:
2502:
2479:
2475:
2471:
2467:
2463:
2460:
2439:
2436:
2424:Standard Model
2419:
2416:
2358:
2355:
2340:
2337:
2333:phantom energy
2320:
2317:
2314:
2311:
2291:
2288:
2285:
2282:
2262:
2258:
2254:
2251:
2248:
2228:
2225:
2222:
2211:
2210:
2199:
2194:
2191:
2188:
2185:
2182:
2179:
2176:
2172:
2168:
2165:
2138:
2118:
2098:
2095:
2092:
2089:
2080:with pressure
2056:
2053:
2049:
2045:
2042:
2015:
1993:
1990:
1986:
1982:
1979:
1966:
1963:
1948:
1945:
1941:
1937:
1934:
1912:
1909:
1905:
1901:
1898:
1874:
1871:
1867:Doppler effect
1838:
1835:
1833:
1830:
1817:Hubble horizon
1789:Main article:
1786:
1783:
1749:Main article:
1746:
1743:
1719:Main article:
1716:
1713:
1711:
1708:
1692:
1688:
1682:
1678:
1674:
1671:
1668:
1638:
1634:
1630:
1627:
1623:
1619:
1615:
1587:
1583:
1577:
1573:
1569:
1566:
1563:
1560:
1540:
1537:
1531:
1528:
1505:
1494:speed of light
1481:
1457:
1446:energy density
1433:
1409:
1398:
1397:
1386:
1381:
1375:
1371:
1367:
1361:
1357:
1349:
1345:
1340:
1337:
1331:
1328:
1324:
1318:
1314:
1311:
1308:
1302:
1299:
1294:
1289:
1286:
1251:
1223:
1203:
1200:
1197:
1177:
1130:
1127:
1110:
1090:
1079:
1078:
1067:
1061:
1058:
1052:
1049:
1043:
1040:
1011:
1008:
982:
979:
948:
945:
852:Wendy Freedman
774: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:
24:
14:
13:
10:
9:
6:
4:
3:
2:
5222:
5211:
5208:
5206:
5203:
5201:
5198:
5196:
5193:
5192:
5190:
5180:
5170:
5168:
5158:
5156:
5151:
5146:
5144:
5134:
5132:
5127:
5122:
5118:
5107:
5106:
5093:
5087:
5084:
5082:
5079:
5077:
5074:
5072:
5069:
5067:
5064:
5062:
5059:
5057:
5054:
5052:
5049:
5047:
5044:
5043:
5041:
5037:
5031:
5028:
5026:
5023:
5021:
5018:
5016:
5013:
5011:
5008:
5006:
5003:
5001:
4998:
4997:
4995:
4991:
4985:
4982:
4980:
4977:
4975:
4972:
4970:
4967:
4965:
4962:
4961:
4959:
4955:
4949:
4946:
4944:
4941:
4940:
4938:
4934:
4928:
4925:
4923:
4920:
4918:
4915:
4913:
4910:
4908:
4905:
4903:
4900:
4899:
4897:
4893:
4887:
4884:
4882:
4879:
4877:
4874:
4872:
4869:
4867:
4864:
4863:
4861:
4859:Past universe
4857:
4851:
4848:
4846:
4843:
4841:
4838:
4836:
4833:
4832:
4830:
4824:
4818:
4815:
4813:
4810:
4808:
4805:
4803:
4800:
4798:
4795:
4794:
4792:
4788:
4784:
4777:
4772:
4770:
4765:
4763:
4758:
4757:
4754:
4747:
4744:
4741:
4738:
4736:
4732:
4729:
4726:
4723:
4719:
4715:
4712:
4709:
4705:
4703:
4699:
4696:
4692:
4691:
4687:
4682:
4678:
4674:
4671:
4670:
4665:
4661:
4658:
4654:
4651:
4647:
4646:
4642:
4632:
4627:
4620:
4617:
4612:
4608:
4603:
4598:
4594:
4590:
4583:
4580:
4575:
4571:
4567:
4563:
4559:
4555:
4550:
4545:
4541:
4537:
4530:
4527:
4522:
4518:
4513:
4508:
4504:
4500:
4493:
4490:
4485:
4481:
4477:
4473:
4469:
4465:
4461:
4457:
4452:
4447:
4444:(1): 97–109.
4443:
4439:
4432:
4429:
4424:
4420:
4416:
4412:
4408:
4404:
4399:
4394:
4390:
4386:
4379:
4376:
4363:
4359:
4352:
4349:
4344:
4342:9780691019338
4338:
4334:
4329:
4328:
4319:
4316:
4304:
4300:
4293:
4290:
4285:
4283:9781451624458
4279:
4275:
4271:
4270:
4265:
4259:
4256:
4250:
4245:
4238:
4235:
4230:
4226:
4222:
4218:
4214:
4210:
4206:
4202:
4197:
4192:
4188:
4184:
4183:
4175:
4172:
4160:
4159:
4154:
4147:
4144:
4139:
4135:
4131:
4127:
4123:
4119:
4114:
4109:
4105:
4101:
4094:
4091:
4079:
4075:
4069:
4066:
4061:
4057:
4052:
4047:
4043:
4039:
4034:
4029:
4025:
4021:
4017:
4009:
4006:
4000:
3997:
3991:
3988:
3983:
3979:
3975:
3971:
3967:
3963:
3958:
3953:
3949:
3945:
3941:
3934:
3931:
3926:
3922:
3918:
3914:
3910:
3906:
3901:
3896:
3892:
3888:
3887:
3882:
3875:
3872:
3867:
3861:
3845:
3844:www.stsci.edu
3841:
3834:
3831:
3826:
3822:
3818:
3814:
3810:
3806:
3802:
3795:
3792:
3779:
3775:
3771:
3768:Allen, Nick.
3764:
3761:
3757:
3751:
3748:
3745:. pp. 137–146
3744:
3740:
3736:
3730:
3727:
3722:
3721:
3716:
3710:
3707:
3702:
3698:
3694:
3690:
3686:
3679:
3676:
3671:
3667:
3663:
3659:
3655:
3651:
3647:
3643:
3638:
3633:
3630:(7419): 176.
3629:
3625:
3621:
3614:
3611:
3606:
3602:
3598:
3594:
3590:
3586:
3582:
3578:
3577:
3568:
3564:
3560:
3556:
3552:
3548:
3544:
3540:
3539:
3531:
3528:
3523:
3517:
3514:
3509:
3505:
3501:
3497:
3496:
3488:
3485:
3479:
3476:
3470:
3467:
3461:
3458:
3452:
3450:
3446:
3440:
3437:
3425:
3424:
3419:
3415:
3409:
3406:
3399:
3395:
3392:
3391:
3387:
3385:
3381:
3379:
3374:
3370:
3367:
3362:
3355:
3353:
3351:
3347:
3343:
3339:
3335:
3334:Hubble radius
3331:
3326:
3322:
3318:
3313:
3311:
3307:
3303:
3300:
3296:
3292:
3288:
3280:
3278:
3275:
3274:vacuum energy
3270:
3268:
3264:
3260:
3256:
3255:FLRW geometry
3251:
3249:
3245:
3240:
3239:superclusters
3236:
3232:
3228:
3224:
3220:
3215:
3212:
3204:
3200:
3193:
3191:
3189:
3185:
3181:
3177:
3169:
3167:
3163:
3159:
3156:
3152:
3148:
3144:
3139:
3135:
3131:
3127:
3126:compact space
3123:
3119:
3118:
3113:
3112:
3107:
3104:The ultimate
3102:
3100:
3096:
3092:
3088:
3084:
3080:
3072:
3070:
3068:
3063:
3058:
3056:
3052:
3048:
3044:
3040:
3036:
3032:
3028:
3023:
3021:
3017:
3013:
3008:
3006:
3001:
2996:
2992:
2987:
2983:
2978:
2976:
2972:
2967:
2964:
2959:
2957:
2953:
2949:
2945:
2940:
2938:
2934:
2923:
2919:
2915:
2911:
2907:
2900:
2889:
2874:
2871:
2856:
2853:
2845:
2834:
2831:
2827:
2824:
2820:
2817:
2813:
2810:
2806:
2803: –
2802:
2798:
2797:Find sources:
2791:
2787:
2781:
2780:
2775:This section
2773:
2769:
2764:
2763:
2754:
2751:
2743:
2733:
2729:
2723:
2722:
2717:This section
2715:
2706:
2705:
2700:
2698:
2691:
2690:
2685:
2684:
2679:
2674:
2665:
2664:
2658:
2653:
2651:
2649:
2645:
2639:
2637:
2633:
2629:
2624:
2622:
2607:
2603:
2599:
2595:
2590:
2588:
2582:
2580:
2559:
2555:
2551:
2547:
2543:
2539:
2530:
2525:
2518:
2516:
2511:
2503:
2501:
2499:
2495:
2477:
2473:
2469:
2465:
2461:
2458:
2449:
2445:
2437:
2435:
2433:
2429:
2425:
2417:
2415:
2413:
2408:
2406:
2402:
2398:
2394:
2390:
2386:
2382:
2378:
2374:
2368:
2364:
2356:
2350:
2345:
2338:
2336:
2334:
2318:
2315:
2312:
2309:
2289:
2286:
2283:
2280:
2260:
2256:
2252:
2249:
2246:
2226:
2223:
2220:
2197:
2189:
2186:
2183:
2177:
2174:
2170:
2166:
2163:
2156:
2155:
2154:
2152:
2136:
2116:
2096:
2093:
2090:
2087:
2079:
2078:perfect fluid
2074:
2072:
2054:
2051:
2047:
2043:
2040:
2031:
2029:
2013:
1991:
1988:
1984:
1980:
1977:
1964:
1962:
1946:
1943:
1939:
1935:
1932:
1910:
1907:
1903:
1899:
1896:
1888:
1884:
1880:
1872:
1870:
1868:
1864:
1860:
1855:
1853:
1849:
1844:
1836:
1831:
1829:
1827:
1822:
1818:
1813:
1811:
1805:
1803:
1799:
1792:
1784:
1782:
1779:
1775:
1771:
1770:time dilation
1767:
1763:
1759:
1752:
1744:
1742:
1740:
1736:
1732:
1728:
1722:
1714:
1709:
1707:
1704:
1690:
1686:
1680:
1676:
1672:
1669:
1666:
1658:
1654:
1636:
1632:
1628:
1625:
1617:
1604:
1601:
1585:
1581:
1575:
1571:
1567:
1564:
1561:
1558:
1538:
1535:
1529:
1526:
1495:
1479:
1471:
1455:
1447:
1431:
1423:
1407:
1384:
1379:
1373:
1369:
1359:
1355:
1347:
1343:
1338:
1335:
1329:
1326:
1322:
1316:
1312:
1309:
1306:
1300:
1297:
1292:
1287:
1284:
1273:
1272:
1271:
1269:
1265:
1249:
1240:
1238:
1221:
1201:
1198:
1195:
1175:
1167:
1162:
1160:
1156:
1152:
1148:
1140:
1135:
1128:
1126:
1124:
1108:
1088:
1065:
1056:
1050:
1047:
1038:
1028:
1027:
1026:
1025:according to
1006:
977:
966:
962:
958:
954:
946:
944:
934:
933:
928:
924:
923:David Spergel
912:
908:
896:
892:
888:
884:
881:
877:
865:
862:, offering a
861:
860:Virgo Cluster
857:
853:
849:
844:
841:
835:
831:
827:
822:
820:
816:
812:
808:
803:
800:
799:Knut Lundmark
795:
793:
789:
785:
781:
777:
776:Vesto Slipher
772:
770:
766:
758:
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:
245:
240:
237:
233:
230:
228:
225:
224:
223:
222:
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:
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:
38:
34:
33:
30:
19:
5179:Solar System
5096:
5020:Reionization
4979:Quintessence
4916:
4912:Hubble's law
4680:
4667:
4656:
4649:
4619:
4592:
4588:
4582:
4539:
4535:
4529:
4502:
4498:
4492:
4441:
4437:
4431:
4388:
4384:
4378:
4366:. Retrieved
4362:the original
4351:
4326:
4318:
4306:. Retrieved
4302:
4292:
4268:
4258:
4237:
4186:
4180:
4174:
4162:. Retrieved
4156:
4146:
4103:
4099:
4093:
4081:. Retrieved
4077:
4068:
4023:
4019:
4008:
3999:
3990:
3947:
3943:
3933:
3890:
3884:
3874:
3848:. Retrieved
3843:
3833:
3808:
3804:
3794:
3782:. Retrieved
3778:the original
3773:
3763:
3755:
3750:
3742:
3729:
3718:
3709:
3692:
3688:
3678:
3627:
3623:
3613:
3580:
3574:
3542:
3536:
3530:
3516:
3502:(8): 56–57.
3499:
3493:
3487:
3478:
3469:
3460:
3439:
3427:. Retrieved
3421:
3408:
3382:
3375:
3371:
3363:
3359:
3314:
3284:
3271:
3262:
3252:
3226:
3216:
3213:
3209:
3197:
3173:
3164:
3160:
3115:
3111:a posteriori
3109:
3108:of space is
3103:
3076:
3061:
3059:
3054:
3050:
3046:
3042:
3038:
3034:
3030:
3024:
3019:
3009:
3005:pseudosphere
2979:
2968:
2960:
2941:
2936:
2930:
2866:
2848:
2839:
2829:
2822:
2815:
2808:
2796:
2784:Please help
2779:verification
2776:
2746:
2737:
2718:
2694:
2687:
2681:
2680:Please help
2677:
2640:
2625:
2605:
2591:
2583:
2557:
2534:
2513:
2441:
2438:Matter epoch
2427:
2421:
2412:scale factor
2409:
2381:false vacuum
2370:
2212:
2075:
2032:
2028:scale factor
1968:
1876:
1856:
1852:scale factor
1841:An object's
1840:
1814:
1806:
1794:
1777:
1766:hyperboloids
1754:
1724:
1705:
1399:
1241:
1166:scale factor
1163:
1144:
1080:
965:Hubble's law
950:
930:
845:
826:Walter Baade
823:
815:Edwin Hubble
804:
796:
773:
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:
5167:Spaceflight
5039:Experiments
4974:Dark matter
4964:Dark energy
4902:FLRW metric
4391:(11): 105.
3784:19 November
3429:21 February
3342:light-years
3338:gigaparsecs
3235:Hubble Flow
3231:Local Group
2975:such models
2914:light years
2740:August 2015
2529:blueshifted
2510:Dark energy
2504:Dark energy
1873:Temperature
1848:Hubble flow
1739:FLRW metric
1735:Hubble flow
1264:FLRW metric
1155:dark energy
1123:cosmic time
953:homogeneous
921:. In 2003,
883:light-curve
880:visual-band
824:Astronomer
769:dark energy
745:dark energy
733:light-years
690:coordinates
306:Experiments
239:Dark matter
232:Dark energy
174:FLRW metric
111:Backgrounds
5189:Categories
4969:Dark fluid
4957:Components
4826:History of
4790:Background
4398:2011.01216
4249:1907.04495
4196:1712.06531
4164:22 October
4113:1807.06209
4033:1604.01424
3758:. pp. 5–16
3735:Messier 32
3400:References
3299:Einstein's
3180:black hole
3134:worldlines
3067:integrated
3041:in a time
2812:newspapers
2683:improve it
2387:, such as
1657:photon gas
1153:, such as
887:luminosity
876:Adam Riess
780:redshifted
386:Copernicus
364:Scientists
219:Components
5143:Astronomy
5056:BOOMERanG
4881:Inflation
4783:Cosmology
4631:0809.4573
4602:0810.0153
4595:: 20–30.
4549:0808.1081
4476:1323-3580
4423:226236696
4138:119335614
4060:118630031
4026:(1): 56.
3925:118938423
3720:Space.com
3695:: 49–59.
3654:1476-4687
3637:1212.1359
3605:122950995
3567:125190902
3149:, though
3122:connected
3012:worldline
2963:spacetime
2689:talk page
2462:∝
2444:redshifts
2428:radiation
2316:−
2287:−
2175:−
2167:∝
2164:ρ
2117:ρ
2097:ρ
2052:−
2044:∝
2041:ρ
1989:−
1981:∝
1978:ρ
1944:−
1936:∝
1908:−
1900:∝
1727:structure
1673:ρ
1629:ρ
1626:≪
1568:ρ
1565:−
1530:¨
1504:Λ
1432:ρ
1366:Λ
1327:ρ
1310:π
1301:−
1288:¨
1147:inflation
1060:→
1042:→
1010:→
981:→
957:isotropic
805:In 1927,
790: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
5200:Big Bang
4927:Redshift
4812:Universe
4802:Big Bang
4731:Archived
4698:Archived
4484:13068122
4368:28 April
4266:(2012).
4229:52987203
4221:30333628
4158:Phys.org
3982:10794058
3860:cite web
3670:47038783
3662:23060180
3388:See also
3364:In the "
3246:or the "
3117:a priori
3106:topology
3095:manifold
3091:universe
3083:universe
2842:May 2021
2636:GW170817
2496:and the
2494:galaxies
2395:and the
2373:inflaton
2367:inflaton
2349:Big Bang
2109:, where
2006:, where
1470:pressure
765:Big Bang
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
5131:Physics
5117:Portals
4607:Bibcode
4574:1365918
4554:Bibcode
4517:Bibcode
4505:: 174.
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