A few months ago I explored the history of atomism, especially the role of Epicurus as a fountainhead of modern views in physics and chemistry. But it was not only at the small scale of the atom where Epicurus was ahead of his time by, oh, 2000 years or so. Although most of the writings of Epicurus are lost to us, they were (quite faithfully, it seems) transmitted by Lucretius in his long poem The Nature of Things. Near the end of Book II (lines 1048ff.), Lucretius explains that the universe is infinite and that the earth is only one of many worlds strewn throughout the universe; he even thinks it likely that intelligent beings live on such worlds because the laws of nature are the same throughout the universe (Book II, lines 1072-1075):
If the same Force and the same Nature abide everywhere
To throw together atoms just as they're united here,
You must confess that there are other worlds with other races
Of people and other kinds of animals in other places.
We mostly take such views for granted these days, but they were quite radical in ~300 BC when Epicurus first espoused them, when Lucretius restated them in poetic form ~250 years later, and even moreso in ~1600 AD when they were again brought forward by Giordano Bruno. Sadly, on February 17 1600, Bruno was burnt at the stake for his ideas.
Both Epicurus and Lucretius held these views in large measure because they led to the conclusion that nature is not controlled by the gods. As Lucretius put it (II, 1090-1093):
If you possess a firm grasp of these tenets, you will see
That Nature, rid of harsh taskmasters, all at once is free
And everything she does, does on her own, so that gods play
No part...
One can see why the Church authorities found Bruno such a challenge to their authority (and why Epicurus and Lucretius were so widely loathed for so many centuries). It's unclear to me how much of a direct influence Bruno was on modern science -- perhaps he was merely one of those precursors who is promptly forgotten -- but one thing is for sure: in cosmology, too, the Epicurean hypotheses have been proved out over the centuries during which modern science has developed, so much so that their once-radical proposals are taken for granted as a matter of course. Yet they are anything but.
Some years ago, James Birx published a heartfelt appreciation of Bruno. He concludes that "Giordano Bruno paved the way for the cosmology of our time". However, in large measure Bruno was merely building on the foundation laid by Epicurus and reinforced several hundred years later by Lucretius. Thus it would be more appropriate to say that Epicurus paved the way for the cosmology (and physics and chemistry) of our time. Here again we see that thinkers like Giordano Bruno and (later) Pierre Gassendi played a significant part in advancing "the spiritual, moral and intellectual emancipation of mankind inaugurated by the philosophy of Epicureanism" (as Ludwig von Mises expressed it in Human Action).