'The end of the world' has already begun, U.Washington scientists say (Forwarded)
Andrew Yee
Seattle, Washington
FROM: Vince Stricherz, 206-543-2580, vin...@u.washington.edu
FOR IMMEDIATE RELEASE: Jan. 13, 2003
'The end of the world' has already begun, UW scientists say
In its 4.5 billion years, Earth has evolved from its hot,
violent birth to the celebrated watery blue planet that
stands out in pictures from space. But in a new book, two
noted University of Washington astrobiologists say the
planet already has begun the long process of devolving
into a burned-out cinder, eventually to be swallowed by
the sun.
By their reckoning, Earth's "day in the sun" has reached
4:30 a.m., corresponding to its 4.5 billion-year age. By
5 a.m., the 1 billion-year reign of animals and plants
will come to an end. At 8 a.m. the oceans will vaporize.
At noon -- after 12 billion years -- the ever-expanding
sun, transformed into a red giant, will engulf the planet,
melting away any evidence it ever existed and sending
molecules and atoms that once were Earth floating off
into space.
"The disappearance of our planet is still 7.5 billion
years away, but people really should consider the fate
of our world and have a realistic understanding of where
we are going," said UW astrophysicist Donald Brownlee.
"We live in a fabulous place at a fabulous time. It's a
healthy thing for people to realize what a treasure this
is in space and time, and fully appreciate and protect
their environment as much as possible."
In "The Life and Death of Planet Earth," Brownlee and
UW paleontologist Peter Ward use current scientific
understanding of planets and stars, as well as the
parameters of life, to provide a glimpse of the second
half of life on Earth and what comes after.
The book, a sort of biography of our planet, is being
published today by Times Books, a division of Henry Holt
and Co. It is a sequel to Ward and Brownlee's best-selling
and much-discussed book "Rare Earth," in which they put
forth the hypothesis that simple life is relatively common
in the universe but complex, Earth-like life is exceedingly
rare.
"The Life and Death of Planet Earth" explains how the
myriad life on Earth today was preceded by a long period
of microbial dominance, and the authors contend that
complex life eventually will disappear and be succeeded
again by a period of only microbial life. They say that
higher life will be removed much as it came into being,
ecosystem by ecosystem. Aspects of the planet's past,
such as numbingly cold ice ages, will be relived in the
period of devolution.
"If we do begin to slide into the next glacial cycle,
there probably are grand, planetary-scale engineering
projects that might stop or lessen the effects," Ward
said.
"The big unknowns are whether we can afford to do such
projects and would we really know what to do. If the
planet was cooling, we could, in principle, begin
painting the surface black to collect more heat. Could
we afford it? And what would be the many possible
ramifications of a planet suddenly covered in black
paint? Any planetary remediation project would always
run the risk of making things worse."
Eventually, though, scorching heat will drive land
creatures to the sea for respite. Those that can adapt
will survive for a time, but eventually the oceans will
warm too much for the complex life forms to continue.
"The last life may look much like the first life -- a
single-celled bacterium, survivor and descendant of all
that came before," the authors write. Finally, even the
surviving microbes "will be seared out of existence."
The prospects of humans surviving by moving to some other
habitable planet or moon aren't good, Brownlee and Ward
contend, because even if such a place were found, getting
there would be a huge obstacle. Various probes sent into
space could survive Earth's demise, and just a few grams
of material could arguably carry a DNA sample from every
human, they say, but it's not likely the human species
itself will survive. Long before the planet's final end,
life will become quite challenging, and finally
impossible, for humans.
As the sun gets hotter and grows in size, it will envelop
Mercury and Venus. It is possible it will stop just short
of Earth, the authors say, but the conditions still would
make this a most-inhospitable planet. More likely, though,
the sun will consume Earth as well, severing all the
chemical bonds between molecules and sending its
individual atoms out into space, perhaps eventually to
form new planets. That would leave Mars as the nearest
planet to the sun, and on Mars the fading sun's glow
would be like that of Earth's moon.
That end is still some 7.5 billion years distant, but by
then Earth will have faced a variety of "ends" along the
way, the authors say. The last dinosaur perished long ago.
Still to come are the last elephant, the last tree, the
last flower, the last glacier, the last snowflake, the
last ocean, the last life.
"The Life and Death of Planet Earth" is like its predecessor,
"Rare Earth," in that the authors collected and distilled
some of the latest scientific ideas about the Earth's place
in the universe, Brownlee said. He hopes the new book, like
"Rare Earth," will spark widespread discussion, and give
people a fundamental and realistic view of the past and
future of their planet.
"It's a healthy thing to think of the place of Earth among
the other planets, and its place in the sun. The sun gave
life and ultimately it will bring death."
###
For more information, contact Brownlee at (206) 543-8575
or brow...@bluemoon.astro.washington.edu or Ward at
(206) 543-2962 or ar...@u.washington.edu
IMAGE CAPTION:
[http://www.washington.edu/newsroom/news/images/earthclock.jpg (222KB)]
An illustration from "The Life and Death of Planet Earth"
shows the authors' view of the Earth's clock of life.
(Image credit: Donald Brownlee/Peter Ward)
--
Andrew Yee
ay...@nova.astro.utoronto.ca