If participants in the Dark Ages Lunar Interferometer study have their way, a telescope on the moon will allow astronomers to see 'back in time' and study the young Universe during the first 100 million years of its existence.
Although the night sky is filled with stars, these stars did not form instantaneously after the Big Bang. There was an interval, now called the “Dark Ages,” in which the Universe was unlit by any star.
The most abundant element in the Universe, and the raw material from which stars, planets, and people are formed, is hydrogen. Fortunately, the hydrogen atom can produce a signal in the radio-wavelength part of the spectrum, at 21 cm; a wavelength far longer than what the human eye can detect.