APOD: The Hubble Ultra-Deep Field in Light... (2018 Mar 05)

[APOD Robot]

The Hubble Ultra-Deep Field in Light and Sound

Explanation: Have you heard about the Hubble Ultra-Deep Field? Either way, you've likely not heard about it like this -- please run your pointer over the featured image and listen! The Hubble Ultra-Deep Field (HUDF) was created in 2003-2004 with the Hubble Space Telescope staring for a long time toward near-empty space so that distant, faint galaxies would become visible. One of the most famous images in astronomy, the HUDF is featured here in a vibrant way -- with sonified distances. Pointing to a galaxy will play a note that indicates its approximate redshift. Because redshifts shift light toward the red end of the spectrum of light, they are depicted here by a shift of tone toward the low end of the spectrum of sound. The further the galaxy, the greater its cosmological redshift (even if it appears blue), and the lower the tone that will be played. The average galaxy in the HUDF is about 10.6 billion light years away and sounds like an F#. What's the most distant galaxy you can find? This Astronomy Picture of the Day (APOD) is based on an entry of new site called Astronomy Sound of the Month (AstroSoM).

<< Previous APOD

This Day in APOD

Next APOD >>

[HellCat]

Very cool. Looking forward to checking out ASoM.

But my cursor indicated one pixel was a star in the milky way. I thought the HUDF was purposely taken to avoid all of those buggers.

[Boomer12k]

Interesting...

:---[===] *

[mcarland]

13.1 Billion on the far right, a red dot under a blue spiral.

[Cousin Ricky]

I’m impressed by whatever spectrograph was used to gather all that redshift data.

[g.thooft@uu.nl]

Would be so nice if the sound could be turned on on my browswer. No such luck. Any suggestions?

[De58te]

Very cool. I found out some interesting things. I always thought that the smaller the galaxy was, the farther away it was. But I found a galaxy that is listed as 10 billion ly away and its size was twice as big then this comma , and beside it was a galaxy about the size of this dot . that was just 6 billion ly away. Also surprising about the redshift. Some very distant galaxies at 12.8 billion ly away were a vibrant greenish blue color. What color would they look like without the redshift for an observer who was right there in the galaxy? In the ultraviolet? Or even in the x-ray color?

[Guest]

I found lots of 28.8, and a couple of 13.1,s. What I foun interesting is that some of the older ones seemed to be intertwined with much closer objects. Could we be looking we be looking 'down' the length of 'filaments' of a big-bang stream of matter that only looks like a group from our perspective? There seems to he a lot of them.

[Chris Peterson]

But my cursor indicated one pixel was a star in the milky way. I thought the HUDF was purposely taken to avoid all of those buggers.

I'm not sure there's any 2.4 arcmin square region of the sky that would be entirely clear of local stars. I think the goal was to minimize them.

[BDanielMayfield]

Just a little perspective on what we are seeing here, from the wikipedia article:

Located southwest of Orion in the southern-hemisphere constellation Fornax, the rectangular image is 2.4 arcminutes to an edge,[4] or 3.4 arcminutes diagonally. This is approximately one tenth of the angular diameter of a full moon viewed from Earth (which is less than 34 arcminutes),[5] smaller than a 1 mm by 1 mm square of paper held at 1 meter away, and equal to roughly one thirteen-millionth of the total area of the sky. The image is oriented so that the upper left corner points toward north (−46.4°) on the celestial sphere.

So, a crude way to estimate the number of galaxies in the observable universe is to count up all the specks and blobs in this image and then multiply by 13,000,000 ...

Bruce

[Chris Peterson]

Very cool. I found out some interesting things. I always thought that the smaller the galaxy was, the farther away it was.

The range of star counts in galaxies covers about six orders of magnitude, so you can figure their projected lengths vary by a factor of around a hundred.

[neufer]

---

So, a crude way to estimate the number of galaxies in the observable universe is to count up all the specks and blobs in this image and then multiply by 13,000,000 ...

[BDanielMayfield]

Art, I wasn't actually going to do the count myself of course.

[rstevenson]

Would be so nice if the sound could be turned on on my browswer. No such luck. Any suggestions?

I also hear no sound, though I get the magnifying glass thingy, and the sound is definitely on in my browser.

Rob

[PT+]

This might be the most amazing post on APOD ever! I LOVE this!

[Fred the Cat]

I’m trying to play Twinkle, Twinkle – Little Star but not having much luck. Maybe I’ll try full resolution... This could take longer than those galaxies have shone

I don't seem to be red shift gifted.

[dduggan47]

13.1 Billion on the far right, a red dot under a blue spiral.

I hadn't spotted that one!

There's another 13.1 just under the large galaxy in the center of the picture.

Straight down from that there's another good sized galaxy with a smaller one to its right which sorta seems to point to the right. Just a little bit NNE of that is a 13.1.

The only other one I've found is almost straight down from that just on the very edge.

Haven't seen (or heard) anything older.

[edgardine]

Thank you !
Knowing the distance of each galaxy of the UDF was beyond my expectations.

[Chris Peterson]

Would be so nice if the sound could be turned on on my browswer. No such luck. Any suggestions?

I also hear no sound, though I get the magnifying glass thingy, and the sound is definitely on in my browser

You need to use Chrome or Firefox (not Safari), and make sure that you don't have anything blocking autoplay (which many people do, because normally that last thing anybody wants is videos or sound clips that start playing by themselves when you land on a page).

[neufer]

Click to play embedded YouTube video.

[mason dixon]

So with something like the Hubble Deep Field, does someone or software go around to each little blob and let only that light through a prism to get the elemental spectrum?

If the absorption lines move so much due to redshift, doesn't that make it difficult to truly know that the composition is?

[smidgeonsoft]

This is spectacular! I wish more images were presented in this manner, i.e., using a different sense - sound - to convey a data-point. I have bookmarked it to show to others.

[neufer]

---

If the absorption lines move so much due to redshift, doesn't that make it difficult to truly know that the composition is?

Presumably the simple hydrogen Lyman Series
is used for visible and near UV & infrared.

[Qev]

Some very distant galaxies at 12.8 billion ly away were a vibrant greenish blue color. What color would they look like without the redshift for an observer who was right there in the galaxy? In the ultraviolet? Or even in the x-ray color?

At a guess I would say the were very bright in UV, ie. undergoing intense star formation.

[neufer]

Some very distant galaxies at 12.8 billion ly away were a vibrant greenish blue color. What color would they look like without the redshift for an observer who was right there in the galaxy? In the ultraviolet? Or even in the x-ray color?

At a guess I would say the were very bright in UV, ie. undergoing intense star formation.

The HUDF filters run from 435 nm to 1600 nm.

(Our own retina cone cells only run from 430 nm to 572 nm and are unable to distinguish
a broad green black body star like the sun as actually being green as opposed to white.)

12.8 billion (years in the past) corresponds to a redshift z ~ 6.1

• http://www.astro.ucla.edu/%7Ewright/CosmoCalc.html

Hence, the displayed redshifted (1+z ~ 7.1) colors from violet to red actually run from 61 nm to 225 nm
(corresponding to O to B black body star temperatures from 48,000K to 13,000K).

To an observer who was right there in the galaxy (now) & whose eyes are insensitive
to the UV given off by those O to B stars the galaxies would appear normal.

[To an observer who was right there in the galaxy (12.8 billion years ago) & whose eyes are insensitive
to the UV given off by those O to B stars the early galaxies might appear somewhat bizarre.]