The faint objects, which might be incredibly massive stars or voracious black holes, are too far away to be seen individually but Spitzer has captured convincing evidence of what appears to be the patterns of their infrared light, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Thursday.
The findings suggest the universe's first objects furiously burned huge amounts of cosmic fuel, astrophysicists said.
"These objects would have been tremendously bright," Alexander "Sasha" Kashlinsky of NASA's Goddard Space Flight Center in Greenbelt, Md., said. "We can't yet directly rule out mysterious sources for this light that could be coming from our nearby universe, but it is now becoming increasingly likely that we are catching a glimpse of an ancient epoch."
The universe formed roughly 13.7 billion years ago in the big bang and, in time, cooled.
By around 500 million years later, the first stars, galaxies and black holes began to take shape, and astronomers say some of their "first light" might have taken billions of years to reach the Spitzer Space Telescope.