Clock of Life: A Biography of Planet Earth

"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. 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."

Donald Brownlee, professor of Astronomy, University of Washington.

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.

"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 as the nearest planet to the sun, and on the fading sun's glow would be like that of Earth's moon.

"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."

Link:

http://www.washington.edu/newsroom/news/2003archive/01-03archive/k011303a.html

Comments

[Keith]

I appreciate the article but think the perspective relevant to most is a bit closer time scale than the end od the second half. Perhaps we could do some things quite constructive in the next few centuries, such that the next few thousand centuries could be worth looking forward to for our species. It has been said of predictions about the future, that short term predictions are usually far to optimistic and expectations for the longer term are usually vastly too pessimistic.

Hope for peace, in its many incarnations, of mind, of community. Work for change for the better, even if it is only on your own small patch of ground. Even if one's only range of focus in this regard is for "better" for one's own offspring. That's been where our species has succeeded in the past.