#3: A growing galactic metropolis
In 2011, astronomers using Spitzer detected a very distant collection of galaxies called COSMOS-AzTEC3. The light from this group of galaxies had traveled for more than 12 billion years to reach Earth.
Astronomers think objects like this one, called a proto-cluster, eventually grew into modern galaxy clusters, or groups of galaxies bound together by gravity. COSMOS-AzTEC3 was the most distant proto-cluster ever detected at the time. It provides researchers with a better idea of how galaxies have formed and evolved throughout the history of the universe.
#4: The recipe for ‘comet soup’
When NASA’s Deep Impact spacecraft intentionally smashed into comet Tempel 1 on July 4, 2005, it expelled a cloud of material that contained the ingredients of our solar system’s primordial “soup.” Combining data from Deep Impact with observations by Spitzer, astronomers analyzed that soup and began to identify the ingredients that eventually produced planets, comets and other bodies in our solar system.
Many of the components identified in the comet dust were known comet ingredients, such as silicates, or sand. But there were also surprise ingredients, such as clay, carbonates (found in seashells), iron-bearing compounds, and aromatic hydrocarbons that are found in barbecue pits and automobile exhaust on Earth. The study of these ingredients provides valuable clues about the formation of our solar system.