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    Default Early Earth's Skies were much Brighter



    The Milky Way Galaxy may have been in a Starburst Galaxy phase, w/ Star Formation Rates being about 100x higher, about 2 to 3 billion years ago*. Now, over the past millennium, the Milky Way Galaxy has experienced around one Supernova per century**. Thus, 2 to 3 billion years ago, the Milky Way Galaxy experienced around one Supernova per year. And, Supernovae are often visible for many months on end.
    * Mars may have had Global Ice Ages
    ** List of supernova remnants - Wikipedia, the free encyclopedia [note that some of the listed Supernovae are Extra-Galactic]

    CONCLUSION: 2 to 3 billion years ago, there was probably some Supernova aglow in the Earth's skies, nearly all the time.

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    According to the National Geographic Channel documentary Naked Science -- Comet Mysteries (TV), the 1908 AD Tunguska Impact Event over Siberia produced an afterglow that lit up Europe's night-time skies for several days (~1/100th of a year). And, according to documentaries like the History Channel's Siberian Apocalypse (DVD), such impacts occur about once per hundred years.

    Thus, back when Impact Events were 10,000 times more frequent -- during the Late Heavy Bombardment, for example -- Earth's skies would have been kept perpetually aglow by the near continuous rain of appreciable impactors.

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    Default

    Not so much light pollution.
    Hey, I'm only wearing black until they bring something darker out!

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    Default Re: Early Earth's Skies were much Brighter

    On second thought (this wasn't made clear to me), i suspect, that the Tunguska "glow", persisting for several days, was the ~2000 km2 of Siberian forest, flattened by the blast, burning in its aftermath. The skies over Siberia did not glow, with some sort of persisting auroral discharge (or some such); instead, thousands of square kilometers of forest were afire, and the wildfire took days to burn out.

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    Default Re: Early Earth's Skies were much Brighter

    Quote Originally Posted by Widdekind View Post
    The Milky Way Galaxy may have been in a Starburst Galaxy phase, w/ Star Formation Rates being about 100x higher, about 2 to 3 billion years ago*. Now, over the past millennium, the Milky Way Galaxy has experienced around one Supernova per century**. Thus, 2 to 3 billion years ago, the Milky Way Galaxy experienced around one Supernova per year. And, Supernovae are often visible for many months on end.
    * Mars may have had Global Ice Ages

    ** List of supernova remnants - Wikipedia, the free encyclopedia [note that some of the listed Supernovae are Extra-Galactic]

    CONCLUSION: 2 to 3 billion years ago, there was probably some Supernova aglow in the Earth's skies, nearly all the time.
    I'm confused by your logic. A SN is the end of a star, not the beginning. The birth of a star is typically in a cloud that we can't see through and adds no appreciable light to the night sky.

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    Default Re: Early Earth's Skies were much Brighter

    Quote Originally Posted by Widdekind View Post
    On second thought (this wasn't made clear to me), i suspect, that the Tunguska "glow", persisting for several days, was the ~2000 km2 of Siberian forest, flattened by the blast, burning in its aftermath. The skies over Siberia did not glow, with some sort of persisting auroral discharge (or some such); instead, thousands of square kilometers of forest were afire, and the wildfire took days to burn out.
    I agree. The models I've seen of this did throw a cloud around the earth that would have dimmed the sun during the day and reflected back the fire at night locally.

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