A different 'Big bang' may have saved Earth
- URL to an article that appeared in USA Today
First few paragraphs
"A different 'Big Bang' may have saved Earth
By Dan Vergano, USA TODAY
SAN DIEGO — An exploding star in our solar system's infancy may have saved
Earth from extinction.
Astronomers studying the planet-forming disks of dust that orbit young,
distant stars are hoping to solve the mystery of our own solar system's youth. Why
is our system so different in form and function from others they can see?
It's a difference that may have saved Earth, because the scientists suspect
that Jupiter and Saturn would have collided with the planet — or slung it out
of the solar system like a slingshot — if the disk surrounding our young sun
hadn't been so damaged.
These "protoplanetary" disks were a hot topic at a recent meeting of the
American Astronomical Society. "Something very bad happened to our solar system's
disk in its early years," says Steve Desch of Arizona State University in
An exploding star, or supernova, likely occurred within a light-year — about
5.9 trillion miles — of our sun in its infancy, he argues. (The closest star
to our solar system now, Proxima Centauri, is about 4 light-years away).
First spotted by an infrared satellite in the 1980s, the disks are the
swirling leftovers of nebulas, pockets of gas within galaxies that spawn new stars.
Some of this dust compresses into planets, more of which have been discovered
orbiting nearby stars during the past decade. A presentation at the meeting
about a Hubble Space Telescope survey of 25 nearby stars, all youngsters less
than 10 million years old, provides evidence that dust disks congeal into more
compact bodies over only a few million years.
Over time, the rest of the dust is blown away by solar wind or other effects.
What is left behind is a solar system like our own.
Glances at nearby disks, and some leftover clues, are telling researchers how
things began for our sun. And it looks like we may inhabit a solar system
that's something of a runt because of the damage from an exploding star.
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