How Exploding Stars May Have Shaped Earth’s History

Jul 15, 2016

By Rebecca Boyle

The aftermath of a star’s death can rival the events of a creation myth. When a star explodes in a supernova, hurling pieces of itself into the cosmos, it seeds new stars and new worlds with the raw materials required for life. In death, stars are reborn. But like all creation tales, this one has a dark side. Supernovae can rain radiation and death onto living worlds that already exist. And they might be able to change the course of natural history.

One such change might have happened on Earth sometime between 1.7 and 3.2 million years ago. A star about nine times the mass of the sun blew up, and the night sky glowed a bright blue for weeks, during which the supernova outshone the full moon. Long after the darkness returned, lightning set off by cosmic rays would have arced from the sky to the ground, and the planet’s climate may have changed. Animals on land and in the shallow sea would have been doused with waves of radiation. Over time, the influx of particles could have sparked mutations in DNA, making small alterations that could have shifted the course of evolution.

From our vantage point on Earth, supernovae appear suddenly; their name comes from the word for “new star.” Their brilliant, visible shine fades away within a few days or weeks, but they continue firing a stupendous surge of x-rays, gamma rays and speedy, energetic particles for much longer. Only recently have astronomers brought these supernovae down to Earth, by wondering how they might have interfered with the planet’s climate, and the evolutionary processes that were playing out on its surface.


Continue reading by clicking the name of the source below.

4 comments on “How Exploding Stars May Have Shaped Earth’s History

  • @OP – One such change might have happened on Earth sometime between 1.7 and 3.2 million years ago. A star about nine times the mass of the sun blew up, and the night sky glowed a bright blue for weeks, during which the supernova outshone the full moon. Long after the darkness returned, lightning set off by cosmic rays would have arced from the sky to the ground, and the planet’s climate may have changed. Animals on land and in the shallow sea would have been doused with waves of radiation.

    We were discussing these sorts of events in this earlier discussion on where we might find life in zones of the galaxy.

    https://www.richarddawkins.net/2016/06/yes-there-have-been-aliens/#li-comment-205325
    Near the black hole at its centre where there are numerous very active flaring stars close together, the radiation is probably too intense for life to last for any length of time, even if it gets started.



    Report abuse

  • Alan,

    A bit off topic, perhaps, but my niece just found a small rock that appears cut in half, is completely smooth and flat on one side; could that possibly be a meteorite? What can that be? It doesn’t seem natural.



    Report abuse

  • Dan #2
    Jul 20, 2016 at 2:50 pm

    Alan,

    A bit off topic, perhaps, but my niece just found a small rock that appears cut in half, is completely smooth and flat on one side; could that possibly be a meteorite? What can that be? It doesn’t seem natural.

    It’s hard to say without seeing it or testing it. Maybe – maybe not!

    I have a beautiful small rock cut in half showing concentric layers of colourful crystals, but that is a nodule from a volcanic vent which has been cross-sectioned with a rock-saw.
    The examples on the link are hollow, but my specimen is solid.

    https://en.wikipedia.org/wiki/Geode

    Meteorites come in many forms, but flat sides usually indicate cutting or breakage.



    Report abuse

Leave a Reply

View our comment policy.