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{{Wikipedia dispute|Hubble Deep Field}}
{{Wikipedia dispute|Hubble Deep Field}}
{{Sky|12|36|49.4|+|62|12|58|100000000000}}
[[File:HubbleDeepField.800px.jpg|thumb|300px|The Hubble Deep Field]]
[[File:HubbleDeepField.800px.jpg|thumb|300px|The Hubble Deep Field]]


The '''Hubble Deep Field''' ('''HDF''') is an image of a small region in the [[constellation]] [[Ursa Major]], constructed from a series of observations by the [[Hubble Space Telescope]]. It covers an area about 2.6 [[arcminute]]s on a side, about one 24-millionth of the whole sky, which is equivalent in angular size to a [[tennis ball]] at a distance of 100&nbsp;metres.<ref>{{cite book |title=The Big Questions The Universe |first1=Stuart |last1=Clark |publisher=Hachette UK |year=2011 |isbn=978-1-84916-609-6 |page=69 |url=https://books.google.com/books?id=PkVhBQAAQBAJ}}</ref> The image was assembled from 342 separate exposures taken with the Space Telescope's [[Wide Field and Planetary Camera 2]] over ten consecutive days between December 18 and December 28, 1995.<ref name="Ferguson1998" /><ref name="Hubble_image" />
The '''Hubble Deep Field''' ('''HDF''') is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope. It covers an area about 2.6 arcminutes on a side, about one 24-millionth of the whole sky, which is equivalent in angular size to a tennis ball at a distance of 100&nbsp;metres. The image was assembled from 342 separate exposures taken with the Space Telescope's Wide Field and Planetary Camera 2 over ten consecutive days between December 18 and December 28, 1995.


The field is so small that only a few foreground [[star]]s in the [[Milky Way]] lie within it; thus, almost all of the 3,000 objects in the image are [[galaxy|galaxies]]. In mainstream astronomy the image is read as a view of the early universe, on the understanding that the redshifts of those galaxies measure their distance and therefore their look-back time.
The field is so small that only a few foreground stars in the Milky Way lie within it; thus, almost all of the 3,000 objects in the image are galaxies. In mainstream astronomy the image is read as a view of the early universe, on the understanding that the redshifts of those galaxies measure their distance and therefore their look-back time.


That reading is what makes the deep fields contentious. Because the [[Big Bang]] model predicts that the distant universe should look ''different'' — less evolved, dimmer per unit area, and eventually empty of galaxies altogether — the deep fields are among the most direct tests the model has ever been given. Many of the researchers catalogued on this wiki argue that it failed them: that the most distant galaxies look disconcertingly like nearby ones, that their surface brightness does not dim as expansion requires, and that every increase in telescope depth has simply revealed more galaxies rather than an edge. Those arguments, and the non-expanding cosmologies advanced in their place, are set out in the [[#Criticism and reinterpretation by researchers on this wiki|criticism section below]].
That reading is what makes the deep fields contentious. Because the [[Big Bang]] model predicts that the distant universe should look ''different'' — less evolved, dimmer per unit area, and eventually empty of galaxies altogether — the deep fields are among the most direct tests the model has ever been given. Many of the researchers catalogued on this wiki argue that it failed them: that the most distant galaxies look disconcertingly like nearby ones, that their surface brightness does not dim as expansion requires, and that every increase in telescope depth has simply revealed more galaxies rather than an edge. Those arguments, and the non-expanding cosmologies advanced in their place, are set out in the [[#Criticism and reinterpretation by researchers on this wiki|criticism section below]].


Three years after the HDF observations were taken, a region in the south celestial hemisphere was imaged in a similar way and named the [[Hubble Deep Field South]]. The similarities between the two regions strengthened the belief that the [[universe]] is uniform over large scales and that the Earth occupies a typical region in the Universe (the [[cosmological principle]]). A wider but shallower survey was also made as part of the [[Great Observatories Origins Deep Survey]]. In 2004 a deeper image, known as the [[Hubble Ultra-Deep Field]] (HUDF), was constructed from a few months of light exposure. The HUDF image was at the time the most sensitive [[astronomy|astronomical]] image ever made at visible wavelengths, and it remained so until the [[Hubble eXtreme Deep Field]] (XDF) was released in 2012.
==The image and how it was made==


==Conception==
[[File:Hubble Deep Field location.gif|thumb|300px|The HDF is at the centre of this image of one degree of sky. The Moon as seen from Earth would fill roughly one quarter of this image.]]
[[File:Improvement in Hubble images after SMM1.jpg|thumb|300px|left|The dramatic improvement in Hubble's imaging capabilities after corrective [[optics]] were installed encouraged attempts to obtain very deep images of distant [[Galaxy|galaxies]].]]


One of the key aims of the astronomers who designed the Hubble Space Telescope was to use its high [[optical resolution]] to study distant galaxies to a level of detail that was not possible from the ground. Positioned above the [[atmosphere]], Hubble avoids atmospheric [[airglow]] allowing it to take more sensitive [[Visible light|visible]] and [[ultraviolet light]] images than can be obtained with seeing-limited ground-based telescopes (when good [[adaptive optics]] correction at visible wavelengths becomes possible, 10&nbsp;m ground-based telescopes may become competitive). Although the telescope's mirror suffered from [[spherical aberration]] when the telescope was launched in 1990, it could still be used to take images of more distant galaxies than had previously been obtainable. Because [[Speed of light|light takes billions of years]] to reach Earth from very distant galaxies, we see them as they were billions of years ago; thus, extending the scope of such research to increasingly distant galaxies allows a better understanding of how they evolve.<ref name=Ferguson1998>Ferguson et al. (1999), p.84</ref>
Robert Williams, then director of the Space Telescope Science Institute, committed a large share of his director's discretionary time in 1995 to imaging a single ordinary patch of sky for as long as possible. The field had to sit at high galactic latitude, away from the dust of the Milky Way, free of bright foreground sources, and inside Hubble's northern continuous viewing zone so that northern observatories could follow it up. Three candidates in Ursa Major survived those cuts; the one chosen lies at right ascension 12h 36m 49.4s, declination +62° 12′ 58″.


After the spherical aberration was corrected during [[Space Shuttle]] mission [[STS-61]] in 1993,<ref name="Trauger1994">Trauger et al. (1994)</ref> the improved imaging capabilities of the telescope were used to study increasingly distant and faint galaxies. The [[Medium Deep Survey]] (MDS) used the Wide Field and Planetary Camera 2 (WFPC2) to take deep images of random fields while other instruments were being used for scheduled observations. At the same time, other dedicated programs focused on galaxies that were already known through ground-based observation. All of these studies revealed substantial differences between the properties of galaxies today and those that existed several billion years ago.<ref>Abraham et al. (1996)</ref>
Between 18 and 28 December 1995, over roughly 150 orbits, the Wide Field and Planetary Camera 2 took 342 exposures through four broadband filters centred at 300, 450, 606 and 814 nm — about 141 hours of total exposure. The many short exposures allowed cosmic-ray hits to be identified and removed by comparison, and the telescope was deliberately re-pointed by less than one pixel between exposure sets so that the frames could be combined by "drizzling" to a final resolution finer than the detector's native 0.09 arcseconds per pixel. Three of the four monochrome images were assigned to red, green and blue to produce the familiar colour composite; the filters were chosen for scientific usefulness rather than to reproduce what the eye would see.


Up to 10% of the HST's observation time is designated as Director's Discretionary (DD) Time, and is typically awarded to astronomers who wish to study unexpected transient phenomena, such as [[supernova]]e. Once Hubble's corrective optics were shown to be performing well, [[Robert Williams (astronomer)|Robert Williams]], the then-director of the [[Space Telescope Science Institute]], decided to devote a substantial fraction of his DD time during 1995 to the study of distant galaxies. A special Institute Advisory Committee recommended that the WFPC2 be used to image a "typical" patch of sky at a high [[galactic latitude]], using several [[optical filter]]s. A [[working group]] was set up to develop and implement the project.<ref name="Williams1996">Williams et al. (1996)</ref>
==Contents of the field==


==Target selection==
The final images were released at the American Astronomical Society meeting in January 1996. About 3,000 distinct objects can be identified in a field 2.6 arcminutes across — roughly one twenty-four-millionth of the sky, the angular size of a tennis ball at 100 metres. Fewer than twenty are foreground stars of the Milky Way; essentially everything else is a galaxy, in every apparent shape and size, some spanning only a few pixels. About fifty blue point-like objects are also present, some associated with nearby galaxies and probably regions of intense star formation, others possibly distant quasars or white dwarfs.
[[File:Hubble Deep Field location.gif|thumb|300px|The HDF is at the centre of this image of one [[degree (angle)|degree]] of sky. The Moon as seen from Earth would fill roughly one quarter of this image.]]
[[File:Hubble Ultra Deep Field diagram.jpg|thumb|Diagram illustrating comparative sampling distance of the HDF and the 2004 Hubble Ultra-Deep Field]]
 
The field selected for the observations needed to fulfill several criteria. It had to be at a high galactic latitude, because [[interstellar dust|dust]] and obscuring matter in the plane of the [[Milky Way]]'s disc prevents observations of distant galaxies at low galactic latitudes. The target field had to avoid known bright sources of [[visible light]] (such as foreground stars), and [[infrared]], [[ultraviolet]] and [[X-ray]] emissions, to facilitate later studies at many wavelengths of the objects in the deep field, and also needed to be in a region with a low background [[infrared cirrus|infrared 'cirrus']], the diffuse, wispy infrared emission believed to be caused by warm dust grains in cool clouds of [[hydrogen]] gas ([[H I region]]s).<ref name="Williams1996" />
 
These criteria restricted the field of potential target areas. It was decided that the target should be in Hubble's 'continuous viewing zones' (CVZs)—the areas of sky which are not [[occultation|occulted]] by the Earth or the [[moon]] during Hubble's orbit.<ref name="Williams1996" /> The working group decided to concentrate on the northern CVZ, so that northern-hemisphere telescopes such as the [[Keck telescopes]], the [[Kitt Peak National Observatory]] telescopes and the [[Very Large Array]] (VLA) could conduct follow-up observations.<ref name="north_cvz">
{{cite web
| author = Ferguson, H.
| date = 1996
| url = http://www.stsci.edu/ftp/science/hdf/project/field.html
| title = The Hubble Deep Field—field selection
| publisher = Space Telescope Science Institute
| accessdate = December 26, 2008
}}</ref>
 
Twenty fields satisfying these criteria were initially identified, from which three optimal candidate fields were selected, all within the constellation of [[Ursa Major]]. [[Radio]] snapshot observations with the [[Very Large Array|VLA]] ruled out one of these fields because it contained a bright radio source, and the final decision between the other two was made on the basis of the availability of guide stars near the field: Hubble observations normally require a pair of nearby stars on which the telescope's Fine Guidance Sensors can lock during an exposure, but given the importance of the HDF observations, the working group required a second set of back-up guide stars. The field that was eventually selected is located at a [[right ascension]] of {{RA|12|36|49.4}} and a [[declination]] of {{DEC|+62|12|58}};<ref name="Williams1996" /><ref name="north_cvz" /> it is approximately 2.6 [[arcminute]]s in width,<ref name="Ferguson1998" /><ref name="Ferguson2000a">Ferguson (2000a)</ref> or 1/12 the width of the Moon. The area is approximately 1/28,000,000 of the total area of the sky.<ref name=Curious>{{cite web|url=http://curious.astro.cornell.edu/about-us/98-the-universe/galaxies/observing-galaxies/535-how-big-is-the-hubble-ultra-deep-field-image-intermediate|title=How big is the Hubble Ultra Deep Field image|date=April 2016|publisher=Curious about astronomy? Ask an astronomer.|accessdate=January 7, 2009|author=Anderson, Ryan}}</ref>
 
==Observations==
[[File:Hubble Deep Field observing geometry.svg|thumb|200px|left|The HDF was located in Hubble's northern Continuous Viewing Zone, as shown by this diagram.]]
 
Once a field had been selected, an observing strategy had to be developed. An important decision was to determine which [[filter (optics)|filter]]s the observations would use; WFPC2 is equipped with forty-eight filters, including [[narrowband]] filters isolating particular [[emission line]]s of [[astrophysical]] interest, and [[broadband]] filters useful for the study of the colours of stars and galaxies. The choice of filters to be used for the HDF depended on the '[[throughput]]' of each filter—the total proportion of light that it allows through—and the spectral coverage available. Filters with [[bandpass]]es overlapping as little as possible were desirable.<ref name="Williams1996" />
 
In the end, four broadband filters were chosen, centred at [[wavelength]]s of 300 [[Nanometre|nm]] (near-[[ultraviolet]]), 450&nbsp;nm (blue light), 606&nbsp;nm (red light) and 814&nbsp;nm (near-[[infrared]]). Because the [[quantum efficiency]] of Hubble's detectors is quite low at 300&nbsp;nm, the noise in observations at this wavelength is primarily due to [[charge-coupled device|CCD]] noise rather than sky background; thus, these observations could be conducted at times when high background noise would have harmed the efficiency of observations in other passbands.<ref name="Williams1996" />
 
Between December 18 and December 28, 1995—during which time Hubble orbited the Earth about 150 times—342 images of the target area in the chosen filters were taken. The total exposure times at each wavelength were 42.7 hours (300&nbsp;nm), 33.5 hours (450&nbsp;nm), 30.3 hours (606&nbsp;nm) and 34.3 hours (814&nbsp;nm), divided into 342 individual exposures to prevent significant damage to individual images by [[cosmic ray]]s, which cause bright streaks to appear when they strike CCD detectors. A further 10 Hubble orbits were used to make short exposures of flanking fields to aid follow-up observations by other instruments.<ref name="Williams1996" />
 
==Data processing==
[[File:Galaxy in each of the four wavelengths comprising the HDF.jpg|thumb|300px|A section of the HDF about 14 [[arcseconds]] across in each of the four [[wavelength]]s used to construct the final version: 300 [[Nanometre|nm]] (top left), 450 nm (top right), 606 nm (bottom left) and 814 nm (bottom right)]]
The production of a final combined image at each [[wavelength]] was a complex process. Bright [[pixel]]s caused by cosmic ray impacts during exposures were removed by comparing exposures of equal length taken one after the other, and identifying pixels that were affected by [[cosmic ray]]s in one exposure but not the other. Trails of [[space debris]] and [[artificial satellite]]s were present in the original images, and were carefully removed.<ref name="Williams1996" />
 
Scattered light from the Earth was evident in about a quarter of the data frames, creating a visible "X" pattern on the images. This was removed by taking an image affected by scattered light, aligning it with an unaffected image, and subtracting the unaffected image from the affected one. The resulting image was smoothed, and could then be subtracted from the bright frame. This procedure removed almost all of the scattered light from the affected images.<ref name="Williams1996" />
 
Once the 342 individual images were cleaned of cosmic-ray hits and corrected for scattered light, they had to be combined. Scientists involved in the HDF observations pioneered a technique called '[[Drizzle (image processing)|drizzling]]', in which the pointing of the telescope was varied minutely between sets of exposures. Each pixel on the WFPC2 CCD chips recorded an area of sky 0.09 [[arcsecond]]s across, but by changing the direction in which the telescope was pointing by less than that between exposures, the resulting images were combined using sophisticated image-processing techniques to yield a final angular resolution better than this value. The HDF images produced at each wavelength had final pixel sizes of 0.03985 arcseconds.<ref name="Williams1996" />
 
The data processing yielded four [[monochrome]] images (at 300&nbsp;nm, 450&nbsp;nm, 606&nbsp;nm and 814&nbsp;nm), one at each wavelength.<ref name=Ferguson1/> One image was designated as red (814&nbsp;nm), the second as green (606&nbsp;nm) and the third as blue (450&nbsp;nm), and the three images were combined to give a colour image.<ref name=Hubble_image>{{cite web|publisher=NASA|date=1995|title=Hubble's Deepest View of the Universe Unveils Bewildering Galaxies across Billions of Years|url=http://hubblesite.org/newscenter/archive/releases/1996/01/image/a/|accessdate=12 January 2009}}</ref> Because the wavelengths at which the images were taken do not correspond to the wavelengths of red, green and blue light, the colours in the final image only give an approximate representation of the actual colours of the galaxies in the image; the choice of filters for the HDF (and the majority of Hubble images) was primarily designed to maximize the scientific utility of the observations rather than to create colours corresponding to what the [[human eye]] would actually perceive.<ref name=Ferguson1>Ferguson et al. (1999), p.88</ref>
 
==Contents of the Deep Field==
[[File:ALMA probes the Hubble Ultra Deep Field.jpg|thumb|Deep field image taken by [[Atacama Large Millimeter Array|ALMA]] and Hubble.<ref>{{cite web|title=ALMA Explores the Hubble Ultra Deep Field - Deepest ever millimetre observations of early Universe|url=http://www.eso.org/public/news/eso1633/|website=www.eso.org|accessdate=24 September 2016}}</ref>]]
 
The final images were released at a meeting of the [[American Astronomical Society]] in January 1996,<ref name="key_findings">
{{cite web
| date = 1997
| url = http://oposite.stsci.edu/pubinfo/PR/97/hdf-key-findings.html
| title = Summary of Key Findings From the Hubble Deep Field
| accessdate = December 26, 2008
| publisher = Space Telescope Science Institute
| archiveurl=https://archive.is/20110701011536/http://oposite.stsci.edu/pubinfo/PR/97/hdf-key-findings.html|archivedate=July 1, 2011}}</ref> and revealed a plethora of distant, faint galaxies. About 3,000 distinct galaxies could be identified in the images,<ref name="Ferguson2000b">Ferguson et al. (2000b)</ref> with both [[irregular galaxy|irregular]] and [[spiral galaxy|spiral galaxies]] clearly visible, although some galaxies in the field are only a few pixels across. In all, the HDF is thought to contain fewer than twenty galactic foreground stars; by far the majority of objects in the field are distant galaxies.<ref name="Flynn1996" />
 
There are about fifty blue point-like objects in the HDF. Many seem to be associated with nearby galaxies, which together form chains and arcs: these are likely to be regions of intense [[star formation]]. Others may be distant [[quasar]]s. Astronomers initially ruled out the possibility that some of the point-like objects are [[white dwarf]]s, because they are too blue to be consistent with theories of white dwarf evolution prevalent at the time. However, more recent work has found that many white dwarfs become bluer as they age, lending support to the idea that the HDF might contain white dwarfs.<ref name="Hansen1998">Hansen (1998)</ref>


==The standard interpretation==
==The standard interpretation==
[[File:HDF extracts showing many galaxies.jpg|thumb|250px|left|Details from the HDF illustrate the wide variety of galaxy shapes, sizes and colours found in the distant universe.]]
The HDF data provided extremely rich material for cosmologists to analyse and by late 2014 the associated scientific paper for the image had received over 900 citations.<ref name="nasa_ads"><!-- Referencing the _citation count_, not the article -->{{cite journal | title=NASA ADS entry for Williams et al. (1996) | publisher=The SAO/NASA Astrophysics Data System | bibcode=1996AJ....112.1335W |author1=Williams, Robert E. |author2=Blacker, Brett |author3=Dickinson, Mark |author4=Dixon, W. Van Dyke |author5=Ferguson, Henry C. |author6=Fruchter, Andrew S. |author7=Giavalisco, Mauro |author8=Gilliland, Ronald L. |author9=Heyer, Inge |author10=Katsanis, Rocio |author11=Levay, Zolt |author12=Lucas, Ray A. |author13=McElroy, Douglas B. |author14=Petro, Larry |author15=Postman, Marc |author16=Adorf, Hans-Martin |author17=Hook, Richard | volume=112 | date=1996 | page=1335 | journal=Astronomical Journal | doi=10.1086/118105|arxiv = astro-ph/9607174 }}</ref> One of the most fundamental findings was the discovery of large numbers of galaxies with high [[redshift]] values.
As the Universe expands, more distant objects recede from the Earth faster, in what is called the [[Hubble Flow]]. The light from very distant galaxies is significantly affected by the [[Redshift#Expansion of space|cosmological redshift]]. While [[quasar]]s with high redshifts were known, very few galaxies with redshifts greater than one were known before the HDF images were produced.<ref name="key_findings" /> The HDF, however, contained many galaxies with redshifts as high as six, corresponding to distances of about 12 billion [[light-year]]s. Due to redshift the most distant objects in the HDF ([[Lyman-break galaxy|Lyman-break galaxies]]) are not actually visible in the Hubble images; they can only be detected in images of the HDF taken at longer wavelengths by ground-based telescopes.<ref name=Ferguson2>Ferguson et al. (1999), p.105</ref>
The HDF galaxies contained a considerably larger proportion of disturbed and irregular galaxies than the local universe;<ref name="key_findings" /> galaxy collisions and mergers were more common in the young universe as it was much smaller than today. It is believed that giant [[elliptical galaxy|elliptical galaxies]] form when spirals and irregular galaxies collide.
The wealth of galaxies at different stages of their evolution also allowed astronomers to estimate the variation in the rate of [[star formation]] over the lifetime of the Universe. While estimates of the redshifts of HDF galaxies are somewhat crude, astronomers believe that star formation was occurring at its maximum rate 8–10 billion years ago, and has decreased by a factor of about 10 since then.<ref name="Connolly1997">Connolly et al. (1997)</ref>
Another important result from the HDF was the very small number of foreground stars present.  For years astronomers had been puzzling over the nature of [[dark matter]], mass which seems to be undetectable but which observations implied made up about 90% of the mass of the Universe.<ref name="Trimble1987">Trimble (1987)</ref> One theory was that dark matter might consist of Massive Astrophysical Compact Halo Objects ([[MACHO]]s)—faint but massive objects such as [[red dwarf]]s and [[planet]]s in the outer regions of galaxies.<ref name="Alcock1992">Alcock et al. (1992)</ref> The HDF showed, however, that there were not significant numbers of red dwarfs in the outer parts of our galaxy.<ref name="key_findings" /><ref name="Flynn1996">Flynn et al. (1996)</ref>
==Multifrequency followup==
[[File:Hubble Deep Field by Spitzer.jpg|thumb|The HDF imaged by the [[Spitzer Space Telescope]]. The top segment shows the foreground objects in the field; the bottom shows the background with the foreground objects removed.]]
Very-high redshift objects (Lyman-break galaxies) cannot be seen in visible light and generally are detected in [[Infrared astronomy|infrared]] or [[Submillimetre astronomy|submillimetre]] wavelength surveys of the HDF instead.<ref name=Ferguson2/> Observations with the [[Infrared Space Observatory]] (ISO) indicated infrared emission from 13 galaxies visible in the optical images, attributed to large quantities of dust associated with intense star formation.<ref name="RowanRobinson1997">Rowan-Robinson et al. (1997)</ref> Infrared observations have also been made with the [[Spitzer Space Telescope]].<ref>{{cite web
| title = GOODS Spitzer and Ancillary Data
| url = http://irsa.ipac.caltech.edu/data/SPITZER/GOODS/
| publisher = NASA/IPAC Infrared Science Archive
| accessdate = January 7, 2009
}}</ref> Submillimeter observations of the field have been made with [[James Clerk Maxwell Telescope#Continuum detectors|SCUBA]] on the [[James Clerk Maxwell Telescope]], initially detecting 5 sources, although with very low resolution.<ref name="Ferguson2000b" /> Observations have also been made with the [[Subaru (telescope)|Subaru]] telescope in Hawaii.<ref name="hdf_clearinghouse">
{{cite web
| last = Ferguson | first = H.
| date = 2002
| url = http://www.stsci.edu/ftp/science/hdf/clearinghouse/clearinghouse.html
| title = HDF Clearinghouse
| publisher = Space Telescope Science Institute
| accessdate = December 27, 2008
}}</ref>
X-ray observations by the [[Chandra X-ray Observatory]] revealed six sources in the HDF, which were found to correspond to three elliptical galaxies: one spiral galaxy, one [[active galactic nucleus]] and one extremely red object, thought to be a distant galaxy containing a large amount of [[dust]] absorbing its blue light emissions.<ref name="Hornschemeier2000">Hornschemeier et al. (2000)</ref>


Ground-based radio images taken using the VLA revealed seven radio sources in the HDF, all of which correspond to galaxies visible in the optical images.<ref name="Kellerman1998">Kellerman et al. (1998)</ref> The field has also been surveyed with the [[Westerbork Synthesis Radio Telescope]] and the [[MERLIN]] array of radio telescopes at 1.4&nbsp;GHz;<ref name="wsrt">Garratt et al. (2000)</ref><ref name="merlin">
[[File:HDF extracts showing many galaxies.jpg|thumb|250px|left|Details from the HDF illustrate the wide variety of galaxy shapes, sizes and colours found in the field.]]
{{cite web
| url=http://www.merlin.ac.uk/topics/deepfield/index.html
| title=Preliminary MERLIN Observations of the HST Deep Field
| publisher=[[Jodrell Bank Observatory]]
| accessdate=December 27, 2008
}}<!-- DEADLINK --></ref> the combination of VLA and MERLIN maps made at wavelengths of 3.5 and 20&nbsp;cm have located 16 radio sources in the HDF-N field, with many more in the flanking fields.<ref name="Ferguson2000b" /> Radio images of some individual sources in the field have been made with the [[European VLBI Network]] at 1.6&nbsp;GHz with a higher resolution than the Hubble maps.<ref name="evn">Garrett et al. (2001)</ref>


==Subsequent HST observations==
In mainstream cosmology the field is read as a core sample of cosmic history. Redshift is taken to measure recession velocity and hence distance, so faint high-redshift galaxies — the HDF contains many, some quoted as high as ''z'' = 6 — are understood to be seen as they were billions of years ago. On that reading the image supports the conclusions that galaxies were more disturbed and irregular in the past, that mergers were more frequent, that the cosmic star-formation rate peaked 8–10 billion years ago and has since fallen by roughly a factor of ten, and that faint red dwarfs are too few to account for dark matter. Follow-up observations at other wavelengths — with the Infrared Space Observatory, Spitzer, SCUBA on the James Clerk Maxwell Telescope, Chandra, the VLA, MERLIN and others — detected infrared, submillimetre, X-ray and radio counterparts to objects in the field.
<div style="float:left;margin-right:1em;">
{|
|- valign="top"
|[[File:Hubble Deep Field South full mosaic.jpg|thumb|The [[Hubble Deep Field South]] looks very similar to the original HDF, demonstrating the [[cosmological principle]].]]
|[[File:Hubble ultra deep field high rez edit1.jpg|thumb|The [[Hubble Ultra-Deep Field]] further corroborates this.]]
|}
</div>


An HDF counterpart in the southern celestial hemisphere was created in 1998: the [[Hubble Deep Field South|HDF-South]].<ref name="Williams2000">Williams et al. (2000)</ref> Created using a similar observing strategy,<ref name="Williams2000" /> the HDF-S was very similar in appearance to the original HDF.<ref name="Casertano2000">Casertano et al. (2000)</ref> This supports the [[cosmological principle]] that at its largest scale the Universe is [[Homogeneity (physics)|homogeneous]]. The HDF-S survey used the [[Space Telescope Imaging Spectrograph]] (STIS) and the [[Near Infrared Camera and Multi-Object Spectrometer]] (NICMOS) instruments installed on the HST in 1997; the Hubble Deep Field has since been re-observed several times using WFPC2, as well as by the NICMOS and STIS instruments.<ref name="Ferguson2000a" /><ref name="Ferguson2000b" /> Several [[supernova]] events were detected by comparing the first and second epoch observations of the HDF-N.<ref name="Ferguson2000b" />
A southern counterpart, the Hubble Deep Field South, was imaged in 1998 and looks much like the original, which is usually cited as support for the cosmological principle. Deeper images followed: the Hubble Ultra-Deep Field in 2004 and the Hubble eXtreme Deep Field in 2012, whose galaxies are attributed to the first 500 million years after the Big Bang.


A wider survey, but less sensitive, was carried out as part of the [[Great Observatories Origins Deep Survey]]; a section of this was then observed for longer to create the [[Hubble Ultra-Deep Field]], which was the most sensitive optical deep field image for years<ref name="Beckwith2006">Beckwith et al. (2006)</ref> until the [[Hubble eXtreme Deep Field]] was completed in 2012.<ref>{{cite news|title=Hubble goes to the eXtreme to assemble the deepest ever view of the Universe|url=http://www.spacetelescope.org/news/heic1214/|accessdate=25 September 2012|newspaper=Hubble press release}}</ref> Images from the Extreme Deep Field, or XDF, were released on 26 September 2012 to a number of media agencies. Images released in the XDF show galaxies which are now believed to have formed in the first 500 million years following the Big Bang.<ref>[http://hubblesite.org/newscenter/archive/releases/2012/37/image/a/ Hubble Site News Center]</ref><ref>[https://www.theguardian.com/science/2012/sep/26/hubble-astronomers-deepest-view-night-sky|Hubble Astronomers Release Deepest View of the Night Sky]</ref>
The remainder of this article sets out why the researchers catalogued on this wiki dispute that interpretation.
{{clear}}


==What the deep fields were expected to show==
==What the deep fields were expected to show==
Line 241: Line 146:


==See also==
==See also==
{{Portal|Astronomy|Cosmology}}
* [[List of Deep Fields]]
* [[Big Bang]]
* [[Big Bang]]
* [[Eternal Universe]]
* [[Eternal Universe]]
Line 254: Line 157:
* [[:Category:Cosmology|Category: Cosmology]]
* [[:Category:Cosmology|Category: Cosmology]]


==Notes and references==
==References==
{{Reflist|30em}}


==Bibliography==
The primary technical description of the observations is R. E. Williams et al., "The Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry", ''Astronomical Journal'' '''112''', 1335 (1996). Sources for the criticism sections are cited inline above.
{{refbegin|colwidth=60em}}
* {{cite journal
  | last = Abraham
  | first = R.G.
  |display-authors=etal
  | date = 1996
  | title = The Morphologies of Distant Galaxies. II. Classifications from the Hubble Space Telescope Medium Deep Survey
  | bibcode = 1996ApJS..107....1A
  | journal = Astrophysical Journal Supplement
  | volume = 107
  | pages = 1–17
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* {{cite journal
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}}
{{refend}}


==External links==
==External links==
{{Commonscat-inline|Hubble Deep Field}}
* {{cite web | url=http://www.stsci.edu/ftp/science/hdf/hdf.html | title=The Hubble Deep Field | publisher=STScI}} Main Hubble Deep Field website.
* {{cite web | url=http://hubblesite.org/newscenter/archive/1996/01 | title=Hubble's Deepest View of the Universe Unveils Bewildering Galaxies across Billions of Years | date=January 15, 1996}} NASA's original press release.
* {{cite web| url=http://www.salon.com/comics/opus/2007/08/05/opus/| title=Opus Cartoon| publisher=salon| deadurl=yes| archiveurl=https://web.archive.org/web/20090414051143/http://www.salon.com/comics/opus/2007/08/05/opus/| archivedate=2009-04-14| df=}} Opus Cartoon.


{{Hubble Space Telescope}}
* [http://www.stsci.edu/ftp/science/hdf/hdf.html The Hubble Deep Field] — Space Telescope Science Institute project site.
* [http://hubblesite.org/newscenter/archive/1996/01 "Hubble's Deepest View of the Universe Unveils Bewildering Galaxies across Billions of Years"] — NASA press release, 15 January 1996.
* [https://arxiv.org/abs/astro-ph/0509611 Lerner, "Evidence for a Non-Expanding Universe: Surface Brightness Data From HUDF"] (2006).
* [https://arxiv.org/abs/1405.0275 Lerner, Falomo & Scarpa, "UV surface brightness of galaxies from the local universe to z ~ 5"] (2014).
* [https://arxiv.org/abs/1803.08382 Lerner, "Observations contradict galaxy size and surface brightness predictions that are based on the expanding universe hypothesis"], ''MNRAS'' 477, 3185 (2018).
* [https://web.archive.org/web/20160128151632/http://metaresearch.org/cosmology/BB-top-30.asp Van Flandern, "The Top 30 Problems with the Big Bang"] (2002, archived).
* [http://www.cosmologystatement.org/ "An Open Letter to the Scientific Community"], ''New Scientist'', 22 May 2004.


[[Category:Hubble Space Telescope images]]
[[Category:Physical cosmology]]
[[Category:Ursa Major (constellation)]]
[[Category:Astronomy image articles]]
[[Category:1995 photographs]]
[[Category:Sky regions]]
[[Category:Cosmology|Hubble Deep Field]]
[[Category:Cosmology|Hubble Deep Field]]
[[Category:Redshift]]
[[Category:Redshift]]
[[Category:Astronomy]]

Latest revision as of 20:55, 20 July 2026

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Wikipedia Dispute: wikipedia:Hubble Deep Field

This Natural Philosophy wiki page disputes content found on Wikipedia page wikipedia:Hubble Deep Field


The Hubble Deep Field

The Hubble Deep Field (HDF) is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope. It covers an area about 2.6 arcminutes on a side, about one 24-millionth of the whole sky, which is equivalent in angular size to a tennis ball at a distance of 100 metres. The image was assembled from 342 separate exposures taken with the Space Telescope's Wide Field and Planetary Camera 2 over ten consecutive days between December 18 and December 28, 1995.

The field is so small that only a few foreground stars in the Milky Way lie within it; thus, almost all of the 3,000 objects in the image are galaxies. In mainstream astronomy the image is read as a view of the early universe, on the understanding that the redshifts of those galaxies measure their distance and therefore their look-back time.

That reading is what makes the deep fields contentious. Because the Big Bang model predicts that the distant universe should look different — less evolved, dimmer per unit area, and eventually empty of galaxies altogether — the deep fields are among the most direct tests the model has ever been given. Many of the researchers catalogued on this wiki argue that it failed them: that the most distant galaxies look disconcertingly like nearby ones, that their surface brightness does not dim as expansion requires, and that every increase in telescope depth has simply revealed more galaxies rather than an edge. Those arguments, and the non-expanding cosmologies advanced in their place, are set out in the criticism section below.

The image and how it was made

The HDF is at the centre of this image of one degree of sky. The Moon as seen from Earth would fill roughly one quarter of this image.

Robert Williams, then director of the Space Telescope Science Institute, committed a large share of his director's discretionary time in 1995 to imaging a single ordinary patch of sky for as long as possible. The field had to sit at high galactic latitude, away from the dust of the Milky Way, free of bright foreground sources, and inside Hubble's northern continuous viewing zone so that northern observatories could follow it up. Three candidates in Ursa Major survived those cuts; the one chosen lies at right ascension 12h 36m 49.4s, declination +62° 12′ 58″.

Between 18 and 28 December 1995, over roughly 150 orbits, the Wide Field and Planetary Camera 2 took 342 exposures through four broadband filters centred at 300, 450, 606 and 814 nm — about 141 hours of total exposure. The many short exposures allowed cosmic-ray hits to be identified and removed by comparison, and the telescope was deliberately re-pointed by less than one pixel between exposure sets so that the frames could be combined by "drizzling" to a final resolution finer than the detector's native 0.09 arcseconds per pixel. Three of the four monochrome images were assigned to red, green and blue to produce the familiar colour composite; the filters were chosen for scientific usefulness rather than to reproduce what the eye would see.

Contents of the field

The final images were released at the American Astronomical Society meeting in January 1996. About 3,000 distinct objects can be identified in a field 2.6 arcminutes across — roughly one twenty-four-millionth of the sky, the angular size of a tennis ball at 100 metres. Fewer than twenty are foreground stars of the Milky Way; essentially everything else is a galaxy, in every apparent shape and size, some spanning only a few pixels. About fifty blue point-like objects are also present, some associated with nearby galaxies and probably regions of intense star formation, others possibly distant quasars or white dwarfs.

The standard interpretation

Details from the HDF illustrate the wide variety of galaxy shapes, sizes and colours found in the field.

In mainstream cosmology the field is read as a core sample of cosmic history. Redshift is taken to measure recession velocity and hence distance, so faint high-redshift galaxies — the HDF contains many, some quoted as high as z = 6 — are understood to be seen as they were billions of years ago. On that reading the image supports the conclusions that galaxies were more disturbed and irregular in the past, that mergers were more frequent, that the cosmic star-formation rate peaked 8–10 billion years ago and has since fallen by roughly a factor of ten, and that faint red dwarfs are too few to account for dark matter. Follow-up observations at other wavelengths — with the Infrared Space Observatory, Spitzer, SCUBA on the James Clerk Maxwell Telescope, Chandra, the VLA, MERLIN and others — detected infrared, submillimetre, X-ray and radio counterparts to objects in the field.

A southern counterpart, the Hubble Deep Field South, was imaged in 1998 and looks much like the original, which is usually cited as support for the cosmological principle. Deeper images followed: the Hubble Ultra-Deep Field in 2004 and the Hubble eXtreme Deep Field in 2012, whose galaxies are attributed to the first 500 million years after the Big Bang.

The remainder of this article sets out why the researchers catalogued on this wiki dispute that interpretation.

What the deep fields were expected to show

Because light takes time to travel, an image this faint is also an image of the remote past — that much is not in dispute. What is in dispute is what the past should look like. If the universe began 13.8 billion years ago and has been expanding ever since, the deep fields were expected to deliver three things:

  1. Evolution with distance. The most distant galaxies should be visibly immature — small, clumpy, blue, chemically primitive, and assembled out of mergers — because there had not yet been time to build large, ordered, metal-rich systems.
  2. Rapid surface-brightness dimming. In any Friedmann–Robertson–Walker expanding model, surface brightness falls as (1+z)−4 in bolometric units, or (1+z)−3 when measured in AB magnitudes per unit angular area. This is the Tolman test, and it is independent of the values chosen for the cosmological parameters. In a non-expanding universe surface brightness is instead constant with distance.
  3. An end to the galaxies. A universe of finite age has a horizon. Looking deeper should eventually reach an epoch before galaxies existed.

The critics catalogued on this wiki argue that the deep fields delivered none of the three cleanly, and that each shortfall was absorbed by adding a free parameter — evolution, size evolution, dust, reionization history — rather than by revisiting the assumption that redshift measures recession.

Criticism and reinterpretation by researchers on this wiki

The "elderly galaxies" problem

The oldest and most persistent objection is that the deep fields show too little evolution. Tom Van Flandern made this the ninth entry in The Top 30 Problems with the Big Bang (2002), later expanded as The Top 50 Problems with the Big Bang:

Tom Van Flandern, The Top 30 Problems with the Big Bang, Meta Research Bulletin 11 (2002); reprinted Apeiron 9(2)

Billie Westergard argued the same case directly from the images in Structure Formation in the Early Big-Bang Universe? Deep & Ultra Deep Fields Say No! (2005), and developed a matter-creation alternative in Structure Formation in the Universe by Spin and Matter Creation. Van Flandern's A Universe Older Than Itself? presses the related timeline problem, and Big Bang Reaches Deflation Stage surveys the accumulating conflicts.

Glenn Borchardt has made this observation the centerpiece of his cosmological writing, coining the term "elderly galaxies" for well-formed spiral systems seen at the greatest look-back times. Writing about the Hubble image reproduced in his book Infinite Universe Theory, he notes that "the spiral galaxies at a distance of 13.2 billion light years were no different than our own Milky Way, which is 13.7 billion years old," and continues:

Of course, the Big Bang Theory claims that we should see younger and younger objects the farther we look out into space. … So far, there is no evidence to support that conjecture. Instead, the presence of the "elderly galaxies" … falsifies the theory.

— Glenn Borchardt, "Still more light found at the 'end of the universe'", Progressive Science Institute blog, 30 January 2019

The argument has strengthened rather than weakened with better instruments. Borchardt has kept a running tally of what he counts as falsifications of the Big Bang, many of them drawn from the James Webb Space Telescope successors to the Hubble deep fields: the confirmation of a well-ordered spiral at z ≈ 11, the finding that the Hubble sequence of galaxy morphologies appears to be already in place at z ≈ 8, and the spectroscopic confirmation of JADES-GS-z14-0 at z = 14.32 — roughly 290 million years after the nominal beginning — in which oxygen has been detected, implying that generations of massive stars had already lived and died.

For accuracy it should be recorded that not every "impossibly early" object survives scrutiny. The six candidate massive galaxies reported by Labbé and colleagues in Nature in 2023 have largely been reinterpreted as compact broad-line active nuclei ("little red dots") with substantially smaller stellar masses, and the once-notorious "Methuselah star" HD 140283 has been re-dated downward from 14.5 to about 12 billion years. The dissident case here rests on the pattern — that each deep image pushes mature structure earlier and is met with a new mechanism — rather than on any single object.

Surface brightness: the Tolman test

The most quantitative challenge mounted from the deep-field data is Eric J Lerner's, and it is notable for having been published in the mainstream literature. Using ultraviolet surface brightnesses of galaxies from the Hubble Ultra Deep Field matched against GALEX observations of nearby galaxies at the same emitted wavelengths, Lerner argued that surface brightness does not dim as expansion requires. In the first version of the analysis, presented at the 2005 Crisis in Cosmology conference, he reported:

Eric J. Lerner, "Evidence for a Non-Expanding Universe: Surface Brightness Data From HUDF", AIP Conference Proceedings 822, 60–74 (2006)

The stakes are large because the predicted effect is large: at z = 6 the expanding and non-expanding predictions differ by a factor of 73, or 343. The fuller study with Renato Falomo and Riccardo Scarpa (International Journal of Modern Physics D 23, 1450058, 2014) found the mean surface-brightness difference between the high-redshift and low-redshift samples to be −0.017 ± 0.05 magnitudes per square arcsecond over the range z = 0.03 to z ≈ 5 — consistent with no dimming at all. Their sharpest point is not the measurement but what the standard model must then assume:

Mathematically, in order to fit the observed constancy of SB data, any expanding universe model must require that the radii of galaxies with constant absolute luminosity evolve exactly as (1 + z)−1.5 in order to cancel out the (1 + z)3 SB dimming.

— Lerner, Falomo & Scarpa (2014)

That is, the size evolution invoked to rescue the Tolman test must conspire to cancel the dimming almost exactly, across two very different galaxy populations. Lerner pursued this in Monthly Notices of the Royal Astronomical Society 477, 3185 (2018), arguing that the published size-evolution mechanisms — "puffing up", major mergers, and minor mergers — each fail quantitatively, requiring gas fractions or merger rates an order of magnitude above what is observed, and that for elliptical galaxies the required evolution implies dynamical masses smaller than their stellar masses, which is physically impossible.

Ari Brynjolfsson reaches a similar conclusion from a different mechanism in Surface Brightness in Plasma-Redshift Cosmology (2006), deriving the observed constancy from plasma redshift in a static universe. Tom Van Flandern also addressed the Tolman test, though his numbers differ from Lerner's: he argued that a transverse-loss tired-light model predicts intensity falling as (1+z)−2, "in good agreement with most observations without any adjustable parameters," against the Big Bang's (1+z)−4.

An honest account must note the mainstream position: the four-paper series by Lubin and Sandage (2001) reports that the Tolman signal is detected and that static models are excluded at high significance — but only after a luminosity-evolution correction is applied. That the conclusion depends on an evolution model is not disputed by either side; it is the whole battleground. Critics of Lerner's papers reply that he tests a single static model chosen to mimic ΛCDM in flux–luminosity behaviour rather than comparing a range of models.

Counting galaxies: the deep fields and infinity

For Glenn Borchardt, the recurring headline that each new deep image contains far more galaxies than the last is not a curiosity but the observational signature of an infinite universe. His Infinite Universe Theory (2007) and Ten Assumptions of Science and the Demise of Cosmogony (2004) argue that the choice between a finite and an infinite universe is an assumption that cannot be proved either way, and that infinity is the assumption that avoids the contradictions:

As is well-known, the BBT was devised and is maintained by mathematicians. Mathematics really cannot yield a satisfactory treatment of infinity, so an assumption of finity comes natural. The problem is that, if one assumes finity at the beginning, one will end up with finity at the end. The argument becomes circular no matter which assumption one uses. I chose infinity (microcosmic and macrocosmic) here because the resulting logical argument avoids the many contradictions inherent in the BBT.

— Glenn Borchardt, "Infinite Universe Theory", Proceedings of the NPA (2007)

On his account the very project of explaining where the universe came from is misconceived. He calls it cosmogony rather than cosmology, and treats the distinction as the heart of the matter:

IUT denies that cosmogony, the study of the origin of the universe, is legitimate. The word "cosmogony" has not seen popular use in cosmology. To do so would imply that an alternative view was possible. … Conservation, the First Law of Thermodynamics, assumes that matter and the motion of matter neither can be created nor destroyed. The BBT, of course, is the most blatant violation of conservation ever devised. The creation of something from nothing is clearly a religious assumption, not a scientific one.

— Glenn Borchardt, "Infinite Universe Theory" (2007)

Applied to the deep fields, the argument is that the galaxy inventory keeps growing with instrumental reach and shows no sign of terminating: the post-HDF census of roughly 120 billion observable galaxies was revised upward to about two trillion once the ultra-deep counts were extrapolated, and Borchardt has predicted a further order-of-magnitude increase as the Webb surveys are completed. Two cautions belong with that claim. The higher figures are extrapolations rather than counts, and the two-trillion estimate is itself contested within the mainstream — Lauer and colleagues' 2021 measurement of the cosmic optical background from beyond the zodiacal light argues for hundreds of billions rather than trillions. What is not contested is the direction of travel: every increase in depth has increased the count.

Tom Van Flandern made a geometrical version of the same point, noting an excess of faint blue galaxies by a factor of ten at magnitude 28 and observing that this "implies that the volume of space is larger than in the Big Bang, where it should get smaller as one looks back in time." He also remarked that the early appearance of bound aggregates of order 100,000 stars remains unsolved in the standard model but "is no mystery in infinite universe models."

If redshift is not distance, the deep field is not a time machine

Every claim about what the deep fields show about the early universe depends on reading redshift as distance and therefore as look-back time. That reading is the point this wiki disputes most often, and if it fails, the deep fields are simply pictures of galaxies at unknown distances.

Halton Arp argued from physically associated objects with discordant redshifts that a large part of the measured redshift is intrinsic and a function of age rather than recession — young matter is born highly redshifted and its redshift declines as it ages. In Observational Cosmology: From High Redshift Galaxies to the Blue Pacific (2005) he put the consequence plainly: "With our galaxy redshifts a function of age, however, the look back time to a distant galaxy shows it to us when it was younger and more intrinsically redshifted. No Doppler recession needed!" The case is made at book length in Seeing Red: Redshifts, Cosmology and Academic Science. On this view the "high-redshift galaxies" of the deep fields need not be either distant or early.

Paul Marmet developed a non-Doppler redshift produced by the interaction of light with the tenuous matter it traverses, in A New Mechanism to Explain Observations Incompatible with the Big Bang (1991), Cosmic Matter and the Nonexpanding Universe (1989, with the radio astronomer Grote Reber), The Cosmological Red Shift in an Unlimited Universe (1995) and Big Bang Cosmology Meets an Astronomical Death (1990). Borchardt's own mechanism is likewise absorptive: light loses energy over distance to the matter in the space it crosses, which he argues also disposes of Olbers' paradox and accounts for the microwave background without a hot beginning. Related mechanisms are collected on this wiki under Tired Light, Plasma Cosmology, and Intrinsic redshift.

Non-expanding cosmologies represented on this wiki

Several complete alternatives to the expanding-universe reading of the deep fields are catalogued here. Thomas B Andrews sets out a static Euclidean framework in Theoretical Basis for a Non-Expanding and Euclidean Universe (1994). Ari Brynjolfsson's plasma-redshift cosmology accounts for both redshift and surface brightness without expansion. Tuomo Suntola's Dynamic Universe, argued in Zero-Energy Space Cancels the Need for Dark Energy (2007), reproduces the supernova magnitude–redshift relation without a cosmological constant. C Johan Masreliez's Scale Expanding Cosmos, developed across Scale Expanding Cosmos Theory I and II, is an expanding model of a different kind, in which scale rather than distance evolves.

Disagreements among the critics

The dissenting literature is not a single school, and the deep fields are one of the places where its internal disagreements are sharpest.

  • Arp rejects tired light. The mechanism most other critics rely on — photons losing energy en route — is one Arp explicitly ruled out, on the grounds that objects with the same path length to the observer show very different redshifts and that the shift is uniform across each object. His alternative is the Narlikar–Arp variable-mass hypothesis, in which particle masses increase with age. Borchardt's absorption redshift and Marmet's and Brynjolfsson's interaction redshifts are incompatible with that reading.
  • The critics do not agree on the numbers. Van Flandern's tired-light model predicts surface brightness falling as (1+z)−2; Lerner's static Euclidean model predicts constancy in AB magnitudes. Both are offered against the Big Bang's (1+z)−4, but they are not the same prediction and the deep-field data cannot confirm both.
  • Not every alternative is static. Masreliez's scale-expanding cosmos and the various matter-creation models accept a changing universe; what they reject is the singular beginning, not change itself.

Recording these disagreements is not a concession. A research literature that argued in one voice about a body of data this rich would be more suspicious, not less.

The mainstream reply

The standard answer to all of the above is that galaxy evolution is real, expected, and observed; that the maturity of high-redshift systems has repeatedly been overstated by photometric estimates later corrected by spectroscopy; that the Tolman test has been carried out and passed once luminosity evolution is accounted for; and that the growth of galaxy counts with instrumental depth is exactly what a finite universe with a horizon predicts, since faint galaxies are numerous and were simply below earlier detection limits. Astronomers cited by the critics — including the authors of the Webb morphology and high-redshift papers — generally do not endorse a non-expanding interpretation of their results.

The dissenting reply, stated most broadly in the 2004 "Open Letter to the Scientific Community" organised by Lerner and signed by Arp, Van Flandern and some thirty others, is that this pattern of accommodation is itself the problem:

The big bang today relies on a growing number of hypothetical entities, things that we have never observed — inflation, dark matter and dark energy are the most prominent examples. Without them, there would be a fatal contradiction between the observations made by astronomers and the predictions of the big bang theory. In no other field of physics would this continual recourse to new hypothetical objects be accepted as a way of bridging the gap between theory and observation.

— "An Open Letter to the Scientific Community", New Scientist, 22 May 2004

Papers on this wiki

Off-wiki, the primary technical sources for the surface-brightness argument are E. J. Lerner, "Evidence for a Non-Expanding Universe: Surface Brightness Data From HUDF", AIP Conf. Proc. 822, 60 (2006); E. J. Lerner, R. Falomo & R. Scarpa, "UV surface brightness of galaxies from the local universe to z ~ 5", Int. J. Mod. Phys. D 23, 1450058 (2014); and E. J. Lerner, "Observations contradict galaxy size and surface brightness predictions that are based on the expanding universe hypothesis", MNRAS 477, 3185 (2018).


See also

References

The primary technical description of the observations is R. E. Williams et al., "The Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry", Astronomical Journal 112, 1335 (1996). Sources for the criticism sections are cited inline above.

External links

Retrieved from "https://wiki.naturalphilosophy.org/index.php?title=Hubble_Deep_Field&oldid=306085"