Talk:Hubble Ultra-Deep Field

diameter
The patch of sky in which the galaxies reside (just one-tenth the diameter of the full moon) [...]. The "diameter" depends on how far away you are from the object observed. Giving a arcsecond number as the Hubble Deep Field article does ([The Hubble Deep Field photo] covers an area 144 arcseconds across, equivalent in angular size to a tennis ball at a distance of 100 metres.) is more precise. --Abdull 08:59, 25 April 2006 (UTC)


 * Sounds good to me. Most people are on the earth when they look at the moon, giving a distance of about 400,000km. I think the moon measurement is worth keeping in too as most people don't know what an arcsecond is, though the tennis ball analogy is also good. Stephen B Streater 16:39, 25 April 2006 (UTC)


 * I just added the phrase "as viewed from Earth" after "diameter of the full moon", which I think keeps it tied to a common reference (á la Stephen B Streater's point) but also making it technically accurate. Ryan McDaniel 20:02, 25 April 2006 (UTC)

...looking back in time more than 13 billion light years. This doesn't seem correct. A light year is a measure of distance, not time. Does the author actually mean "13 billion years"?Frankwomble 18:35, 25 April 2006 (UTC)


 * Yes - but then isn't the Universe around 13 billion years old? Perhaps it's nearer to 14 Bn. Stephen B Streater 19:57, 25 April 2006 (UTC)


 * Technically, one could make the nitpicking argument that they're equivalent, since the Hubble is looking at light, which does, after all, travel one light-year in a year. However, it is confusing; I've changed it to "years". Ryan McDaniel 20:02, 25 April 2006 (UTC)


 * The latest official age of the universe is around 13.7 billion years old. This information is in the latest edition of the Astronomy for Dummies. -- S iva1979 Talk to me  20:24, 25 April 2006 (UTC)

3 arcminutes square is ambiguous. Does it mean 3 square arcminutes, as in 1.732 arcminutes per side, or does it mean 9 square arcminutes, as in 3 arcminutes per side? --76.209.59.227 06:33, 20 January 2007 (UTC)

"...the image covers 11.0 square arcminutes. This is just one-tenth the diameter of the full moon as viewed from Earth": This simply doesn't make sense, "square arcminutes" is a measure of spherical area, while "diameter" is spherical distance. reddish (talk) 09:42, 4 July 2010 (UTC)

Category: Aminov Images
I capitalized this category listing (was "aminov images"), but neither category exists. What are "aminov images", and what's the reason for putting the HUDF in this category? Ryan McDaniel 20:02, 25 April 2006 (UTC)

Slight confusion?
Okay so I'm a little confused, is the image of an area of sky the size of 1/10th of the moon... or is it an image of the sky less than a spec of sand held at arms length?

Everytime i re-read the article my conclusion differs from the last, can someone clear this up please? Thanks Stevey^ 16:11, 8 June 2006 (UTC)


 * Remember it is a tenth of the diameter of the full moon - that's a hundredth of the area of the full moon. Also because of optical illusion, the full moon appears larger than it actually is (half a degree diameter) - at arm's length (about 70 cm), an object 6 mm diameter (about the size of a small pea) would cover the moon. An object 0.6 mm diameter would cover the HUDF pic, and yes, that's about the size of a grain of sand. - MPF 21:22, 8 June 2006 (UTC)


 * Are you eight years old, MPF? It's considerably more than 70 cm for an adult. For generations, drygoods merchants have been measuring yard goods by the distance from their nose to their thumb and forefinger clenched together. The moon (or the sun - they are almost the same size - is the size of a dime held at arm's length - and that's 17.91 mm. A diameter of 1.79 mm is considerably bigger than a grain of sand; it's almost as big as a small peppercorn. ClairSamoht - Help make Wikipedia the most authoritative source of information in the world 21:30, 28 September 2006 (UTC)


 * Oh yeah, that's all clear now, so it's the size of a pomegranete seed resting on a mouses head a hogshead away from an elbow.83.70.248.72 18:02, 23 May 2007 (UTC)

Macroevolution
While reading this article, I have noticed excessive presentation of the unproven theory of macroevolution as fact in such phrases as "..existing when the universe was just 800 million years old." As this is not proven fact, I request that all macroevolution content be removed from this article, or at least stated as theory. Yurimxpxman 19:25, 11 January 2007 (UTC)


 * Forgive my ignorance, but what does macroevolution ("evolution that occurs at or above the level of species") have to do with the age of the universe? Cedlaod 04:22, 13 February 2007 (UTC)


 * Cedlaod, I think we're dealing with a creationist. Anyway, this is a cosmology-related article, and it's based on the principles of Cosmology. That quotation is based on currently accepted cosmological science. Jolb 22:42, 1 March 2007 (UTC)


 * Yurimxpxman, you don't seem to understand what "theory" means in scientific jargon. You're right, macroevolution is not a proven fact, but a valid scientific theory that withstands substantial evidence. From such a theory, facts are concluded based on the evidence. If you will, theories are higher than facts, as they not only explain but produce knowledge. Now, unfortunately for Young Earth Creationism, astronomical theory allows us to conclude that stars are (with insignificant doubt) millions of light years away, and as elementary optics show, it takes millions of years for the light to reach Earth. Therefore the universe is almost definitely at least millions of years old. Now, understanding that, understand in cosmology, dedicated scientists have given a huge amount of effort to produce facts, and through their theoretical findings combined with astronomical data and evidence, including Cosmic microwave background radiation and redshift it appears that the universe is almost definitely billions of years old. That, my friend, is how scientific theory "proves" things, and is why the article should stand as written.  128.253.97.189 (talk) 02:35, 18 September 2008 (UTC)

I'd just like to add my own objection. I'm not a creationist, and I have a science degree. I also have a deep mistrust of 'Big Bang'. A quick look around on Google will reveal that I'm not the only intelligent person who finds this idea being constantly thrust down out throats objectionable. There may be 'evidence' to support 'Big Bang' but it is hardly conclusive. I'd prefer to keep an open mind and I wish others would too. @big Bang' is in any event 'creationism' dressed up in modern clothes. The basic premise is exactly the same - the theorist (observer) replaces God and plays a passive role. Johnpretty010 (talk) 23:55, 13 August 2010 (UTC)


 * Sirs: With all due respect, the big bang theory, until utterly disproven is the dominant paradigm. ANY discussion on its validity or revisionism needs to be discussed on that discussion page. This is a page for a scientific observation, and the conclusions consistent with the big bang theory, and its supporting evidence. This article is about supporting evidence. The redshift of these galaxies is so far off, as to be incredible and fantastic. The discourse here and suppositions are from the words of the scientific community that subscribes to the dominant paradigm, and not an hermetical interpretation. The scientific facts presented here are not shoved down anyone's throat. The experiment was conducted with the view that the big bang was the best lie to explain the observations. If you have a disputing interpretation, I would ask that you have some incidental credentials so as to appear to be engaged in a serious discussion, vs just shoving YOUR interpretation down our throats. In my words: The theorist (observers) interprets the results consistent with the current dominant paradigm, and not in any spiritual way, thus separating it from faith. Scientists grant you freedom of religion, can you grant them freedom of science?

You are welcome to have other interpretations. Science has its interpretation, separate from the creationists interpretation. This is a scientific discussion of theories, not a faith based discussion of beliefs. That discussion belongs elsewhere, but it is not part of science, it is part of faith. You need to learn to separate the two, as you would Apples and rocks. They are two completely separate things. There is no theory of creation. None. There is the word of God, and although it is open to interpretation, that discussion of its interpretation belongs in faith based discussions. The Big Bang theory is a scientific theory of scientific interpretation, it is not based upon faith, but upon scientific principals which although many philosophers view them at odds, but really they are not at odds at all. They are simply ideas and conversations that belong to entirely diffrent domains.

If you would like to see the foundation of science, its in Genesis: 11:6 "6 And the Lord said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do." So, God granted that out imagination and science is unrestrained by faith. I have argued this point with experts in Hermeneutics, Latin, Greek and Hebrew. If you believe that God will not be denied, then you need to grant Gods word, that human imagination will not be denied. You may want to shove that down our throats, but I believe that in both domains of faith and science, you are in over your head. Ignorance threatened the life of Galileo.

"@big Bang' is in any event 'creationism' dressed up in modern clothes." No, Big Bang is a scientific theory, dressed up, and paraded around as a theory, that we have a significant amount of theoretical work done by some of the most brilliant minds of the 20th century. That shows an extraordinary amount of consistency, but is evolving too. Theories evolve. Faith evolves too, but again, they are two separate and entirely different domains. I accept their work and their ideas.

Lastly, If you would prefer to keep an open mind, I ask that you look at what kind of paradigm would have both faith and science to work for the betterment of mankind. The computer you now use, and the internet you are on, are a product of scientific theories exactly like the big bang. Can you seriously give me a concrete refutation of the laws of electro-magnetism? Look at the bigger picture.

We have no less than 7 valid cosmological theories. We have but one God, and one bible. — Preceding unsigned comment added by 67.180.156.92 (talk) 22:58, 23 November 2012 (UTC)

Next One?
Any idea when they might do another one of these? How much telescope time does it take up? --Cngodles 16:24, 6 March 2007 (UTC)
 * It took 4 months to complete all the exposures. No idea if or when they'll do another one, but according to the article, they'd all look pretty much the same anyway. - Tronno ( t | c ) 03:35, 22 March 2007 (UTC)


 * Actually, I think another one will probably be done once Hubble is serviced next year. No deep imaging can be done before then, for two reasons. Firstly the ACS is broken and the only currently working alternative is the WFPC2, which has a much smaller field of view and has already been used to capture the HDF and HDF South. Secondly, Hubble is limping on failing gyros, if you started observing now there's no guarantee the HST wouldn't break before you finished! Although the HUDF took 4 months, that was only 4 months of Directors Discretionary Time (about 10% of the total telescope time), which translates to less about 2 weeks solid observing. Yes, that's a lot, but not beyond reason.
 * Now, the only reasons for more of these deep images are to go back further (ie deeper) and to test the cosmological principle. As has been noted, the three HST deep images look pretty much the same, which is great for the principle. However, we can still go back further, but to do so requires either more exposure time or a more sensitive instrument. The HUDF was motivated mostly because of the (then) new ACS instrument, which was more sensitive and offered a larger field of view than WFPC2. I don't know any details, but my guess is WFC3 (to be installed in the servicing mission) will be even more sensitive. Since the installation of the ACS was followed 18 months later by the HUDF, and since the servicing mission will also fix the gyros, it's my guess that a year or so after the servicing mission a new deep image will be taken (may called the HXDF, for extreme?). Anyone at STSci want to disillusion me? Modest Genius talk 23:16, 24 April 2007 (UTC)
 * Now, the only reasons for more of these deep images are to go back further (ie deeper) and to test the cosmological principle. As has been noted, the three HST deep images look pretty much the same, which is great for the principle. However, we can still go back further, but to do so requires either more exposure time or a more sensitive instrument. The HUDF was motivated mostly because of the (then) new ACS instrument, which was more sensitive and offered a larger field of view than WFPC2. I don't know any details, but my guess is WFC3 (to be installed in the servicing mission) will be even more sensitive. Since the installation of the ACS was followed 18 months later by the HUDF, and since the servicing mission will also fix the gyros, it's my guess that a year or so after the servicing mission a new deep image will be taken (may called the HXDF, for extreme?). Anyone at STSci want to disillusion me? Modest Genius talk 23:16, 24 April 2007 (UTC)


 * Now we have: http://www.nasa.gov/mission_pages/hubble/science/xdf.html --Railjet (talk) 13:03, 26 September 2012 (UTC)

uh, math error?
The article reads:

"It is the deepest image of the universe ever taken in visible light, looking back (to when the universe is thought to have been 800 million years old) more than 13 billion years ago."

if the other articles say that the universe is 3.7 billion years old, shouldn't this read almost 13 billion years old. 13.7 - 0.8 = 12.9

or is the 120 million year possible error taken into account here.. —Preceding unsigned comment added by 74.78.112.107 (talk) 04:31, 12 June 2008 (UTC)


 * The HUDF reveals galaxies that existed as early as just 400 million years after the big bang. But the image also shows much younger galaxies.  It is not a simple snapshot of one particular time in the history of the universe.  See this diagram.  The HUDF shows objects from 400 million years old and yougner, while the HDF shows objects from 1 billion years ago and younger.  The purpose of the HUDF is to study galaxies during the time from about 400 ~ 800 million years after the big bang.  --mikeu talk 13:56, 2 October 2008 (UTC)

Citations!
took out the last paragraph as it had no sources at all. hope this is ok, it makes it look bad with 'citation needed' all over the place. —Preceding unsigned comment added by 62.31.160.221 (talk) 02:11, 17 August 2008 (UTC)

ref
The HUDF is actually two images, one visible and the other infrared. (The image in the article is the visible light image taken with the ACS. The infrared image can be found at http://hubblesite.org/newscenter/archive/releases/2004/07/image/b/ but I'm not sure if it is on commons yet.)  "The combination of ACS and NICMOS images will be used to search for galaxies that existed between 400 and 800 million years... after the big bang." will fix the citation needed but the article will need to be reworded. I'll try to work this into the article next week when I have more time. --mikeu talk 13:16, 2 October 2008 (UTC)

Follow-up Observations
I don't know how to properly edit the article with references, etc., but according to this article, the Hubble is likely to take an image of more distant objects once the upcoming servicing mission is complete. -- 137.240.136.82 (talk) 20:50, 7 May 2009 (UTC)

http://www.msnbc.msn.com/id/30580829/

Hubble UDF Diagram - Merge?
I found a great diagram on this page: http://en.wikipedia.org/wiki/UDFy-38135539 http://en.wikipedia.org/wiki/File:Hubble_Ultra_Deep_Field_diagram.jpg

Should the UDF diagram be merged to the Hubble Ultra Deep Field page?Keelec (talk) 02:45, 24 January 2011 (UTC)

perspective: deep field and ultra deep field
What portion of the visible sky, compared to the original hubble deep field, was imaged by the hubble ultra deep field? I have not had any success finding a valid source making that comparison.

I ask because One section in the original Hubble Deep Field article has a great photo of the area imaged by the deep field - complete with an idea of how big the moon would look to the human eyes. A similar description would give readers some perspective on the hubble ultra deep field.- Tesseract2 (talk) 14:57, 21 August 2011 (UTC)

Definition of Epoch
"The observations were done in two epochs,"

from

" epoch ep·och [ep-uhk or, especially Brit., ee-pok] Show IPA noun 1. a particular period of time marked by distinctive features, events, etc.: The treaty ushered in an epoch of peace and good will. 2. the beginning of a distinctive period in the history of anything: The splitting of the atom marked an epoch in scientific discovery. 3. a point of time distinguished by a particular event or state of affairs; a memorable date: His coming of age was an epoch in his life. 4. Geology . any of several divisions of a geologic period during which a geologic series is formed. Compare age ( def. 12 ) . 5. Astronomy . a. an arbitrarily fixed instant of time or date, usually the beginning of a century or half century, used as a reference in giving the elements of a planetary orbit or the like.

So, I am changing it to the words used in Photography... Session. the mean longitude of a planet as seen from the sun at such an instant or date. " — Preceding unsigned comment added by 67.180.156.92 (talk) 22:24, 23 November 2012 (UTC)

eXtreme Deep Field image seems wrong
The XDF image doesn't make sense: The XDF is supposed to cover a little part of the HUDF, but the image claimed to be of the XDF is showing exactly the same objects as the HUDF images. To me, something seems off. LosD (talk) 06:32, 21 August 2014 (UTC)

Yes, I was confused by the same thing. I took a look at the NASA press releases and accompanying photos. Apparently, NASA is responsible for the confusion. When they released their 2014 version, they called it 'HUDF' even though it was same field of view as the 2012 XDF and not the field of view of the 2004 HUDF. It appears to be actually an enhancement of the 2012 'XDF' but I'm not sure. I tried to clarify the situation in the title of the top photo, but it's a messy situation and, if someone understands the situation beter and can clarify better, have at it...Star-lists (talk) 23:34, 30 May 2015 (UTC)

File:Hubble ultra deep field high rez edit1.jpg to appear as POTD
Hello! This is a note to let the editors of this article know that File:Hubble ultra deep field high rez edit1.jpg will be appearing as picture of the day on September 24, 2014. You can view and edit the POTD blurb at Template:POTD/2014-09-24. If this article needs any attention or maintenance, it would be preferable if that could be done before its appearance on the Main Page. Thanks! — Crisco 1492 (talk) 01:12, 5 September 2014 (UTC)

Merge XDF
Given that: I suggest that we merge Hubble eXtreme Deep Field into this article and redirect that title to here. Discuss. - dcljr (talk) 05:23, 19 June 2016 (UTC)
 * 1) this article discusses the original 2004 image ("HUDF"), the 2012 Hubble eXtreme Deep Field image ("XDF"), and the 2014 updated HUDF image;
 * 2) there seems to be much confusion caused by NASA's use of the same name for the 2004 and 2014 images, while the 2012 and 2014 images cover less of the sky than the 2004 original (see lead sections of both articles);
 * 3) the XDF article is not very large (stub class) and is probably not likely to expand much further;


 * ✅ Paradoctor (talk) 16:53, 28 June 2016 (UTC)

One month after my initial suggestion, I have gone ahead and performed the merge. I did it in a two-step -then- process, as suggested at WP:MERGE. I have also re-redirected the 5 titles that used to redirect to Hubble eXtreme Deep Field to point to this article now (so no double-redirects that I can see). - dcljr (talk) 03:08, 19 July 2016 (UTC)

File:NASA-HS201427a-HubbleUltraDeepField2014-20140603.jpg to appear as POTD soon
Hello! This is a note to let the editors of this article know that File:NASA-HS201427a-HubbleUltraDeepField2014-20140603.jpg will be appearing as picture of the day on August 3, 2016. You can view and edit the POTD blurb at Template:POTD/2016-08-03. If this article needs any attention or maintenance, it would be preferable if that could be done before its appearance on the Main Page. — Chris Woodrich (talk) 00:07, 18 July 2016 (UTC)

Clarification needed on number of galaxies
This article claims in the lead section that the region of space shown in the HUDF image contains "an estimated 10,000 galaxies", then in the second image caption it says, "The smallest, reddest galaxies, of which there are approximately 10,000…", as if it's just one type of galaxy that numbers 10,000. The 2014 NASA source (footnote 1) says simply, "The resulting image… contains approximately 10,000 galaxies…". And a 2004 NASA source originally used in this article (now a subpage linked to from the URL in footnote 9) also says simply, "The HUDF field contains an estimated 10,000 galaxies."

Now, the 2012 NASA source about the XDF image (footnote 6) says, "The new full-color XDF image is even more sensitive, and contains about 5,500 galaxies even within its smaller field of view." This had been reported in the (now-redirected) XDF article as, "The Hubble eXtreme Deep Field adds another 5,500 galaxies to those discovered in the Hubble Ultra-Deep Field", which I changed to say simply, "The XDF contains approximately 5,500 galaxies…" after [//en.wikipedia.org/w/index.php?title=Hubble_Ultra-Deep_Field&diff=730449609&oldid=730449569 merging it] to here, since I didn't interpret the source as claiming 5,500 additional galaxies, but 5,500 total. Now I don't know what to believe.

Presumably the original 2004 HUDF showed the smallest number of galaxies of the three images (since it was the first and least sensitive of the three). The 2012 XDF couldn't have contained roughly half the number of galaxies (5,500) since it was more sensitive and only (supposedly) 80% the size of the original. OTOH, it couldn't have shown 5,500 more galaxies since the 2014 HUDF claims to show the same number of galaxies as the original (and thus, under this interpretation, about 5,500 fewer than the XDF)!

Does anyone know the truth of the matter? Are there any better sources for this info? - dcljr (talk) 20:31, 23 July 2016 (UTC)

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USNO-A2.0 0600-01400432
It seems that this object is a galaxy, not a star - check the position (03 32 38.00016	-27 47 41.8524) in SIMBAD, where it is called [RTG2015] 21671. Hobbema (talk) 00:02, 9 August 2018 (UTC)
 * Probably explained: USNO-A2.0 is based on scans of POSS O and E plates which are not very deep compared to the deep field. So this object does not really exist. The brightest star in the deep field is the white dwarf candidate UDF 1147 (called VCDFS 24541 in SIMBAD), which has an R magnitude of 19.267. It is listed in Stars in the Hubble Ultra Deep Field - Pirzkal et al. 2005ApJ...622..319P. Hobbema (talk) 23:34, 9 August 2018 (UTC)

"One million years" to scan the entire sky seems to be a mistake
Saw the quote about how it would take a million years to scan the entire sky to the same quality and I do not believe that is accurate.

It says the exposures took time "ranging from 134,900 seconds to 347,100 seconds" of total exposure time and that it would take 34 million exposures of this length to cover the entire sky. This is 37.4 to 96.4 minutes total time. The majority of time was not spent making exposures, but likely spent orientating the telescope and other non exposure related tasks.

If the telescope was left open and allowed to sweep the sky at this exposure rate without wasting time for repositioning and just going in an endless stream, it would take a maximum of 2.26 million DAYS, or 6210 years maximum. And a minimum of 2400 years using the shorter time.

Its still a mind blowing length of time, but it is far less than a million years.

DbivansMCMLXXXVI (talk) 03:21, 18 April 2019 (UTC)


 * I think you got the numbers slightly mixed up. Taking only the shortest quoted values, 134,900 seconds is 2248 minutes, which is 37.4 hours (you had that as the minute value).  Multiplied by 36 million, gives 145,000 years.  The likely value will be longer, as I would guess it unrealistic for the telescope to operate continuously in any hypothetical ultra-long run, as I presume there will be fixed re-positioning, data transfer times, calibration etc. etc. that would put a "real world" value at closer to 1M years.  Given how long it is taking to get the JWST launched & operational, it might be realistic that hubble is still needed in 1M years! SFC9394 (talk) 22:35, 18 April 2019 (UTC)