I can read it in two ways (pardon my inexactness, I'm no expert in this field):
1. The telescope will be able to see/observe very distant stars. These stars are, as it were, "behind" of what we can see with smaller telescopes.
2. The telescope will be doing, in fact, "time travel". The ELT will be used to trace really old stars (either very distant, or with a faint light because it was emitted a long time ago and it has become "degraded" as it traveled the universe). So it will be "looking back" to a distant time when those stars were really young and, according to some theories, closer in time to the "Big Bang". SO the ELT will be looking right (straight) back to that time.
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