Chronology of the universe

Diagram of evolution of the (observable part) of the universe from the Big Bang (left), the CMB-reference afterglow, to the present.
9-year WMAP image of the cosmic microwave background radiation (2012). The radiation is isotropic to roughly one part in 100,000.
The Hubble Ultra Deep Fields often showcase galaxies from an ancient era that tell us what the early Stelliferous Era was like
Another Hubble image shows an infant galaxy forming nearby, which means this happened very recently on the cosmological timescale. This shows that new galaxy formation in the universe is still occurring.
Computer simulated view of the large-scale structure of a part of the universe about 50 million light-years across
The predicted main-sequence lifetime of a red dwarf star plotted against its mass relative to the Sun

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology.

- Chronology of the universe
Diagram of evolution of the (observable part) of the universe from the Big Bang (left), the CMB-reference afterglow, to the present.

168 related topics

Relevance

The Big Bang theory, which states that the universe originally expanded from high or infinite density, is widely accepted by physicists.

Cosmogony

For the Björk song, see Cosmogony.

For the Björk song, see Cosmogony.

The Big Bang theory, which states that the universe originally expanded from high or infinite density, is widely accepted by physicists.
The Sumerian tablet containing parts of the Eridu Genesis.

Despite the research, there is currently no theoretical model that explains the earliest moments of the universe's existence (during the Planck epoch) due to a lack of a testable theory of quantum gravity.

The radioactive beta decay is due to the weak interaction, which transforms a neutron into a proton, an electron, and an electron antineutrino.

Weak interaction

Also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, and gravitation.

Also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, and gravitation.

The radioactive beta decay is due to the weak interaction, which transforms a neutron into a proton, an electron, and an electron antineutrino.
A diagram depicting the decay routes due to the charged weak interaction and some indication of their likelihood. The intensity of the lines is given by the CKM parameters.
decay through the weak interaction
The Feynman diagram for beta-minus decay of a neutron into a proton, electron and electron anti-neutrino, via an intermediate heavy boson
Left- and right-handed particles: p is the particle's momentum and S is its spin. Note the lack of reflective symmetry between the states.

The electroweak force separated into the electromagnetic and weak forces during the quark epoch of the early universe.

Graph of cosmic microwave background spectrum measured by the FIRAS instrument on the COBE, the most precisely measured black body spectrum in nature. The error bars are too small to be seen even in an enlarged image, and it is impossible to distinguish the observed data from the theoretical curve.

Cosmic microwave background

Electromagnetic radiation which is a remnant from an early stage of the universe, also known as "relic radiation".

Electromagnetic radiation which is a remnant from an early stage of the universe, also known as "relic radiation".

Graph of cosmic microwave background spectrum measured by the FIRAS instrument on the COBE, the most precisely measured black body spectrum in nature. The error bars are too small to be seen even in an enlarged image, and it is impossible to distinguish the observed data from the theoretical curve.
The Holmdel Horn Antenna on which Penzias and Wilson discovered the cosmic microwave background. The antenna was constructed in 1959 to support Project Echo—the National Aeronautics and Space Administration's passive communications satellites, which used large earth orbiting aluminized plastic balloons as reflectors to bounce radio signals from one point on the Earth to another.
The power spectrum of the cosmic microwave background radiation temperature anisotropy in terms of the angular scale (or multipole moment). The data shown comes from the WMAP (2006), Acbar (2004) Boomerang (2005), CBI (2004), and VSA (2004) instruments. Also shown is a theoretical model (solid line).
This artist's impression shows how light from the early universe is deflected by the gravitational lensing effect of massive cosmic structures forming B-modes as it travels across the universe.
800x800px
Comparison of CMB results from COBE, WMAP and Planck
(March 21, 2013)

According to the Theory of Quantum Fields in Curved Spacetimes the origin of these (thermal) microwave photons is related to redshifted particles created in the early Universe, when the production of particles by the expanding background played a significant role.

Timeline of the metric expansion of space, where space, including hypothetical non-observable portions of the universe, is represented at each time by the circular sections. On the left, the dramatic expansion occurs in the inflationary epoch; and at the center, the expansion accelerates (artist's concept; not to scale).

Big Bang

Prevailing cosmological model explaining the existence of the observable universe from the earliest known periods through its subsequent large-scale evolution.

Prevailing cosmological model explaining the existence of the observable universe from the earliest known periods through its subsequent large-scale evolution.

Timeline of the metric expansion of space, where space, including hypothetical non-observable portions of the universe, is represented at each time by the circular sections. On the left, the dramatic expansion occurs in the inflationary epoch; and at the center, the expansion accelerates (artist's concept; not to scale).
Panoramic view of the entire near-infrared sky reveals the distribution of galaxies beyond the Milky Way. Galaxies are color-coded by redshift.
Artist's depiction of the WMAP satellite gathering data to help scientists understand the Big Bang
Abell 2744 galaxy cluster – Hubble Frontier Fields view.
The cosmic microwave background spectrum measured by the FIRAS instrument on the COBE satellite is the most-precisely measured blackbody spectrum in nature. The data points and error bars on this graph are obscured by the theoretical curve.
9 year WMAP image of the cosmic microwave background radiation (2012). The radiation is isotropic to roughly one part in 100,000.
Focal plane of BICEP2 telescope under a microscope - used to search for polarization in the CMB.
Chart shows the proportion of different components of the universe – about 95% is dark matter and dark energy.
The overall geometry of the universe is determined by whether the Omega cosmological parameter is less than, equal to or greater than 1. Shown from top to bottom are a closed universe with positive curvature, a hyperbolic universe with negative curvature and a flat universe with zero curvature.

Models based on general relativity alone can not extrapolate toward the singularity—before the end of the so-called Planck epoch.

The globular cluster M80. Stars in globular clusters are mainly older metal-poor members of Population II.

Metallicity

Abundance of elements present in an object that are heavier than hydrogen and helium.

Abundance of elements present in an object that are heavier than hydrogen and helium.

The globular cluster M80. Stars in globular clusters are mainly older metal-poor members of Population II.

It follows that older generations of stars, which formed in the metal-poor early Universe, generally have lower metallicities than those of younger generations, which formed in a more metal-rich Universe.

The Large Magellanic Cloud, a satellite galaxy of the Milky Way

Dwarf galaxy

Small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars.

Small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars.

The Large Magellanic Cloud, a satellite galaxy of the Milky Way
Dwarf galaxies like NGC 5264 typically possess around a billion stars.
The Phoenix Dwarf Galaxy is a dwarf irregular galaxy, featuring younger stars in its inner regions and older ones at its outskirts.
UGC 11411 is a galaxy known as an irregular blue compact dwarf (BCD) galaxy.
Blue compact dwarf PGC 51017.
LEDA 677373 is located about 14 million light-years away.
Dwarf galaxy DDO 68.
Dwarf galaxy UGC 685 taken by Hubble.<ref>{{cite web |title=Hubble's Legacy |url=https://www.spacetelescope.org/images/potw1935a/ |website=www.spacetelescope.org |access-date=2 September 2019 |language=en}}</ref>

A 2018 study suggests that some local dwarf galaxies formed extremely early, during the Dark Ages within the first billion years after the big bang.

The Hubble eXtreme Deep Field (XDF) was completed in September 2012 and shows the farthest galaxies ever photographed. Except for the few stars in the foreground (which are bright and easily recognizable because only they have diffraction spikes), every speck of light in the photo is an individual galaxy, some of them as old as 13.2 billion years; the observable universe is estimated to contain more than 2 trillion galaxies.

Cosmology

Branch of metaphysics dealing with the nature of the universe.

Branch of metaphysics dealing with the nature of the universe.

The Hubble eXtreme Deep Field (XDF) was completed in September 2012 and shows the farthest galaxies ever photographed. Except for the few stars in the foreground (which are bright and easily recognizable because only they have diffraction spikes), every speck of light in the photo is an individual galaxy, some of them as old as 13.2 billion years; the observable universe is estimated to contain more than 2 trillion galaxies.
Representation of the observable universe on a logarithmic scale.

In the science of astronomy it is concerned with the study of the chronology of the universe.

Milky Way

Galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye.

Galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye.

The Origin of the Milky Way (c. undefined 1575–1580) by Tintoretto
A view of the Milky Way toward the constellation Sagittarius (including the Galactic Center), as seen from a dark site with little light pollution (the Black Rock Desert, Nevada), the bright object on the lower right is Jupiter, just above Antares
The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center
Photograph of the "Great Andromeda Nebula" from 1899, later identified as the Andromeda Galaxy
Map of the Milky Way Galaxy with the constellations that cross the galactic plane in each direction and the known prominent components annotated including main arms, spurs, bar, nucleus/bulge, notable nebulae and globular clusters.
An all-sky view of stars in the Milky Way and neighbouring galaxies, based on the first year of observations from Gaia satellite, from July 2014 to September 2015.
The map shows the density of stars in each portion of the sky. Brighter regions indicate denser concentrations of stars. Darker regions across the Galactic Plane correspond to dense clouds of interstellar gas and dust that absorb starlight.
Artistic close-up of the Orion Arm with the main features of the Radcliffe Wave and Split linear structures, and with the Solar System surrounded by the closest large scale celestial features at the surface of the Local Bubble at a distance of 400-500 light years.
Diagram of the Sun's location in the Milky Way, the angles represent longitudes in the galactic coordinate system.
The structure of the Milky Way is thought to be similar to this galaxy (UGC 12158 imaged by Hubble)
A schematic profile of the Milky Way.
Abbreviations: GNP/GSP: Galactic North and South Poles
360-degree panorama view of the Milky Way (an assembled mosaic of photographs) by ESO, the galactic centre is in the middle of the view, with galactic north up
360-degree rendering of the Milky Way using Gaia EDR3 data showing interstellar gas, dust backlit by stars (main patches labeled in black; white labels are main bright patches of stars). Left hemisphere is facing the galactic center, right hemisphere is facing the galactic anticenter.
Overview of different elements of the overall structure of the Milky Way.
Illustration of the two gigantic X-ray/gamma-ray bubbles (blue-violet) of the Milky Way (center)
Observed (normal lines) and extrapolated (dotted lines) structure of the spiral arms of the Milky Way, viewed from north of the galaxy – the galaxy rotates clockwise in this view. The gray lines radiating from the Sun's position (upper center) list the three-letter abbreviations of the corresponding constellations
Clusters detected by WISE used to trace the Milky Way's spiral arms.
The long filamentary molecular cloud dubbed "Nessie" probably forms a dense "spine" of the Scutum–Centarus Arm
Galaxy rotation curve for the Milky Way – vertical axis is speed of rotation about the galactic center; horizontal axis is distance from the galactic center in kpcs; the sun is marked with a yellow ball; the observed curve of speed of rotation is blue; the predicted curve based upon stellar mass and gas in the Milky Way is red; scatter in observations roughly indicated by gray bars, the difference is due to dark matter
Comparison of the night sky with the night sky of a hypothetical planet within the Milky Way 10 billion years ago, at an age of about 3.6 billion years and 5 billion years before the Sun formed.
The Milky Way arching at a high inclination across the night sky, (this composited panorama was taken at Paranal Observatory in northern Chile), the bright object is Jupiter in the constellation Sagittarius, and the Magellanic Clouds can be seen on the left; galactic north is downward
The Milky Way viewed at different wavelengths

The oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of the Big Bang.

The chemical elements ordered in the periodic table

Chemical element

A chemical element refers to all aspects of the species of atoms that have a certain number of protons in their nuclei, including the pure substance consisting only of that species.

A chemical element refers to all aspects of the species of atoms that have a certain number of protons in their nuclei, including the pure substance consisting only of that species.

The chemical elements ordered in the periodic table
Estimated distribution of dark matter and dark energy in the universe. Only the fraction of the mass and energy in the universe labeled "atoms" is composed of chemical elements.
Periodic table showing the cosmogenic origin of each element in the Big Bang, or in large or small stars. Small stars can produce certain elements up to sulfur, by the alpha process. Supernovae are needed to produce "heavy" elements (those beyond iron and nickel) rapidly by neutron buildup, in the r-process. Certain large stars slowly produce other elements heavier than iron, in the s-process; these may then be blown into space in the off-gassing of planetary nebulae
Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, from the Big Bang. The next three elements (Li, Be, B) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar-produced elements are: (1) an alternation of abundance in elements as they have even or odd atomic numbers (the Oddo-Harkins rule), and (2) a general decrease in abundance as elements become heavier. Iron is especially common because it represents the minimum energy nuclide that can be made by fusion of helium in supernovae.
Mendeleev's 1869 periodic table: An experiment on a system of elements. Based on their atomic weights and chemical similarities.
Dmitri Mendeleev
Henry Moseley

The lightest chemical elements are hydrogen and helium, both created by Big Bang nucleosynthesis during the first 20 minutes of the universe in a ratio of around 3:1 by mass (or 12:1 by number of atoms), along with tiny traces of the next two elements, lithium and beryllium.

James Webb Space Telescope

Space telescope designed primarily to conduct infrared astronomy.

Space telescope designed primarily to conduct infrared astronomy.

Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light
Test unit of the sunshield stacked and expanded at the Northrop Grumman facility in California, 2014
Engineers cleaning a test mirror with carbon dioxide snow, 2015
Main mirror assembly from the front with primary mirrors attached, November 2016
NIRCam wrapped up in 2013
The Calibration Assembly, one component of the NIRSpec instrument
MIRI
Diagram of the spacecraft bus. The solar panel is in green and the light purple panels are radiators.
Comparison with Hubble primary mirror
The assembled telescope following environmental testing
Early full-scale model on display at NASA Goddard Space Flight Center (2005)
JWST is not exactly at the point, but circles around it in a halo orbit.
Two alternate Hubble Space Telescope views of the Carina Nebula, comparing ultraviolet and visible (top) and infrared (bottom) astronomy. Far more stars are visible in the latter.
Infrared observations can see objects hidden in visible light, such as the HUDF-JD2 shown here.
Atmospheric windows in the infrared: Much of this type of light is blocked when viewed from the Earth's surface. It would be like looking at a rainbow but only seeing one color.
Three-quarter view of the top
Bottom (Sun-facing side)
alt=JWST and Ariane 5 Rollout|Ariane 5 and JWST at the ELA-3 launch pad
alt=Ariane 5 moments after lift-off|Ariane 5 containing JWST moments after lift-off
alt=JWST as seen from the ESC-D Cryotechnic upper stage|JWST as seen from the ESC-D Cryotechnic upper stage shortly after separation, approximately 29 minutes after launch. Part of the Earth with the Gulf of Aden is visible in the background.<ref name=jwstSeparation>Camera on ESC-D Cryotechnic upper stage (25 Dec 2021) view of newly separated JWST, as seen from the ESC-D Cryotechnic upper stage</ref>
Planned structural deployment timeline
Segment Image Identification. 18 mirror segments are moved to determine which segment creates which segment image. After matching the mirror segments to their respective images, the mirrors are tilted to bring all the images near a common point for further analysis.
Segment Alignment begins by defocusing the segment images by moving the secondary mirror slightly. Mathematical analysis, called Phase Retrieval, is applied to the defocused images to determine the precise positioning errors of the segments. Adjustments of the segments then result in 18 well-corrected "telescopes". However, the segments still don't work together as a single mirror.
Image Stacking. To put all of the light in a single place, each segment image must be stacked on top of one another. In the Image Stacking step, the individual segment images are moved so that they fall precisely at the center of the field to produce one unified image. This process prepares the telescope for Coarse Phasing.
Telescope Alignment Over Instrument Fields of View. After Fine Phasing, the telescope will be well aligned at one place in the NIRCam field of view. Now the alignment must be extended to the rest of the instruments.
Selfie: Primary mirror of JWST at destination.<ref name="Webb blog 2022-02-11"/>
18 images of same target star HD 84406 by the 18 unfocused mirror segments.
Phase 1 interim image, annotated with the related mirror segments that took each image.
18 unfocused images of same target star HD 84406.<ref name="Webb blog 2022-02-18" />
Phase 1 annotated completion image of HD 84406.
Phase 2 completion, showing "before and after" effects of segment alignment.
Phase 3 completion, showing 18 segments "stacked" as a single image of HD 84406.
Star 2MASS J17554042+6551277{{efn|2MASS J17554042+6551277, also known as UNSW-V 084 and TYC 4212-1079-1,<ref name="uni1">{{cite web |title=2mass j17554042+6551277 – Facts about the Star |url=https://www.universeguide.com/star/138939/2massj175540426551277 |website=Universe Guide – Guide to Space, Planets and the Rest of the Universe |publisher=universeguide.com |access-date=21 March 2022 |ref=16 March 2022}}</ref> is a star in the constellation Draco, in the Milky Way. It is located almost 2,000 light years away from Earth, within a degree of the north ecliptic pole. Its visual apparent magnitude m{{sub|v}} is 10.95, which makes it much too faint to be observed with the naked eye. It is cooler than the Sun, but some 13 to 16 times brighter in visible light,<ref name="klu1">{{cite news |last1=Kluger |first1=Jeffrey |title=The James Webb Space Telescope Took Its Best Picture Yet |url=https://time.com/6158745/james-webb-space-telescope-picture/ |access-date=21 March 2022 |agency=TIME |publisher=time.com |date=18 March 2022}}</ref> and is consequently not a sun-like star. Its motion vector in the direction of the Sun is 51 km/s. }} captured by NIRCam instrument.
A "selfie" taken by the NIRCam during the alignment process.
Images of sharply focused stars in the field of view of each instrument demonstrate that the telescope is fully aligned and in focus. The sizes and positions of the images shown here depict the relative arrangement of each of Webb's instruments in the telescope's focal plane, each pointing at a slightly offset part of the sky relative to one another.{{efn|For this test, Webb pointed at part of the Large Magellanic Cloud, a small satellite galaxy of the Milky Way, providing a dense field of hundreds of thousands of stars across all the observatory's sensors. Webb's three imaging instruments are NIRCam (images shown here at a wavelength of 2 microns), NIRISS (image shown here at 1.5 microns), and MIRI (shown at 7.7 microns, a longer wavelength revealing emission from interstellar clouds as well as starlight). NIRSpec is a spectrograph rather than imager but can take images, such as the 1.1 micron image shown here, for calibrations and target acquisition. The dark regions visible in parts of the NIRSpec data are due to structures of its microshutter array, which has several hundred thousand controllable shutters that can be opened or shut to select which light is sent into the spectrograph. Lastly, Webb’s Fine Guidance Sensor tracks guide stars to point the observatory accurately and precisely; its two sensors are not generally used for scientific imaging but can take calibration images such as those shown here. This image data is used not just to assess image sharpness but also to precisely measure and calibrate subtle image distortions and alignments between sensors as part of Webb’s overall instrument calibration process.}}<ref>{{cite web |title=NASA’s Webb In Full Focus, Ready for Instrument Commissioning – James Webb Space Telescope |url=https://blogs.nasa.gov/webb/2022/04/28/nasas-webb-in-full-focus-ready-for-instrument-commissioning/ |website=blogs.nasa.gov |access-date=29 April 2022}} {{PD-notice}}</ref><ref name="SD-20220428">{{cite news |last=Cesari |first=Thaddeus |title=NASA’s James Webb Space Telescope Alignment Complete – Capturing Crisp, Focused Images |url=https://scitechdaily.com/nasa-james-webb-space-telescope-alignment-complete-capturing-crisp-focused-images/ |date=29 April 2022 |work=SciTechDaily |accessdate=29 April 2022 }}</ref>
Image comparison between "old" Spitzer and new JWST<ref name="UT-20220502">{{cite news |last=Atkinson |first=Nancy |title=Now, We can Finally Compare Webb to Other Infrared Observatories |url=https://www.universetoday.com/155686/now-we-can-finally-compare-webb-to-other-infrared-observatories/ |date=2 May 2022 |work=Universe Today |accessdate=12 May 2022 }}</ref>

It can detect objects up to 100 times fainter than Hubble can, and objects much earlier in the history of the universe, back to redshift z≈20 (about 180 million years cosmic time after the Big Bang).