The first stars and galaxies are thought to have formed in the Universe within a few hundred million years after the Big Bang. By looking very far away, and so backward in time, we can in principle see back to this era, but in practice what we can learn is limited by the extreme faintness of these early objects.
Gamma-ray bursts, which are the result of the unimaginably violent explosions of very massive stars, are the most luminous objects we know of, and so provide search-lights to explore this distant regime.
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