Hubble and Spitzer Uncover Smallest Galaxy Building Blocks

In this image of the Hubble Ultra Deep Field, several objects are identified as the faintest, most compact galaxies ever observed in the distant Universe. They are so far away that we see them as they looked less than one billion years after the Big Bang. Blazing with the brilliance of millions of stars, each of the newly discovered galaxies is a hundred to a thousand times smaller than our Milky Way Galaxy.

The bottom row of pictures shows several of these clumps (distance expressed in redshift value). Three of the galaxies appear to be slightly disrupted. Rather than being shaped like rounded blobs, they appear stretched into tadpole-like shapes. This is a sign that they may be interacting and merging with neighboring galaxies to form larger structures.

The detection required joint observations between Hubble and NASA's Spitzer Space Telescope. Blue light seen by Hubble shows the presence of young stars. The absence of red light from Spitzer observations conclusively shows that these are truly young galaxies without an earlier generation of stars.


NASA, ESA, and N. Pirzkal (European Space Agency/STScI)

About the Image

NASA press release
Release date:6 September 2007, 18:00
Related releases:heic0714
Size:2750 x 3312 px

About the Object

Name:Hubble Ultra Deep Field, HUDF
Type:Early Universe : Galaxy : Grouping : Cluster

Image Formats

r.titleLarge JPEG
3.3 MB
r.titleScreensize JPEG
395.7 KB

Print Layout

r.titleScreensize JPEG
380.6 KB

Colours & filters

Optical Hubble Space Telescope
Hubble Space Telescope
Spitzer Space Telescope

Also see our

Privacy policy Accelerated by CDN77