Ultra Deep Space
The Cosmic Bacground Radiation CMB was first discovered in the mid-1960s by the Bell Labs researchers Arno Penzias and Robert Wilson. While completing a radio wave survey, their horn shaped antenna picked up a strange hiss. After they reported the result to the physicist Robert Dicke of Princeton, he calculated its temperature and found that it matched the predictions of the Big Bang theory.
This discovery confirmed the existence of an ultra-hot beginning to the universe. It was not precise enough, however, to reveal the fine details of the primordial distribution of matter and energy.
In the early 1990s, thanks to the Nobel prize–winning work of John Mather and George Smoot, using NASA's Cosmic Background Explorer (COBE) satellite, the precise frequency distribution of the microwave background radiation was mapped and established, beyond a shadow of a doubt, that it matched precisely what would be expected for a once-fiery universe cooled down over billions of years.
Smoot and his group discovered a mosaic of minute temperature fluctuations (called anisotropies) throughout the sky, pointing to subtle early differences in the densities of various regions of the cosmos. These fluctuations showed how in the nascent universe slightly denser "seeds" existed that would attract more and more mass and eventually grow into the hierarchical structures (stars, galaxies, clusters of galaxies, and so forth), that we observe today.
The quest to map out the ripples in the CMB with greater and greater precision has continued throughout the past two decades. Uniquely, these provide a wealth of accessible information about the state of the cosmos many billions of years ago. It's like a rare cuneiform tablet that, with improving translations, provides richer and richer insights into ancient history each time it's read.
Galaxy Building Blocks in the Hubble Ultra Deep Field Hubblesite
Hubble & Spitzer find building-block galaxies in early Universe from ESA