Thursday, September 6, 2012

Experiments Scientists Would Do If They Lived Indefinitely

Cover Image: September 2012 Scientific American MagazineSee Inside

What would scientists learn if they could run studies that lasted for hundreds or thousands of years?or more?


Image: Pixelgarten

In Brief

  • Many natural phenomena are difficult to observe because they occur on timescales much longer than a human life.
  • The author asked leading researchers what experiments could be possible if they could live for thousands of years.
  • Experiments had to be based on current technology and had to address a fundamental question that cannot be answered in a shorter time.

A lifetime is very long relative to the picosecond it takes for two atoms to form a molecule, but it is the blink of an eye compared to many natural phenomena, from the rise of mountain chains to the collisions of galaxies. To answer questions that take more than a lifetime to resolve, scientists hand their efforts down from one generation to the next. In medical science, for example, longitudinal studies often follow subjects well after the original researchers have passed; some studies that are still ongoing started as far back as the 1920s. The record for the most extensive sequence of uninterrupted data gathering in history may belong to the ancient Babylonians' Astronomical Diaries, which contain at least six centuries' worth of observations from the first millennium B.C.; those records have revealed recurring patterns in such events as solar and lunar eclipses.

In most fields of scientific research, however, some of the most interesting and fundamental questions remain open because scientists simply have not had enough time to pursue them. But what if time were no object? I recently spoke with leading researchers in various fields about the problems they would attack if they had 1,000 years?or 10,000 or even a million?to make observations or perform experiments. (To keep the focus on the science rather than on futurology, I asked them to assume they could use only technology that is state of the art today.) Condensed versions of their intriguing replies follow.

10,000 YEARS: HOW DID LIFE BEGIN?

Robert Hazen, earth scientist at George Mason University

In the early 1950s Stanley Miller and Harold Urey of the University of Chicago famously showed that some basic building blocks of life, such as amino acids, form spontaneously given the right conditions. It seemed that solving the mystery of the origin of life could be just a matter of combining the right chemicals and waiting long enough. It has not turned out to be that simple, but over 10,000 years or so a modern version of the Urey-Miller experiment might yield some rudimentary self-replicating molecule able to evolve through natural selection?in short, life.

An experiment to simulate the origin of life has to take place in a geochemically plausible environment and start from scratch. The primordial soup may have contained millions of different kinds of small molecules, which could combine and react in an astronomical number of possible ways. In the ocean, though, they would have been so diluted that the chances of any two molecules running into each other, much less reacting chemically, were very low. The most plausible explanation is that self-replicating molecules first assembled on the surface of rocks. The wet surfaces of primordial Earth would have constituted a vast natural laboratory, running perhaps 1030 little experiments at any one time, over a period of maybe 100 million to 500 million years.

A 10,000-year laboratory effort could attempt to re-create this situation by running huge numbers of tiny experiments simultaneously. These molecular nurseries would look from the outside like rooms filled with racks of computer servers, but inside there would be chemical ?labs-on-chips? containing hundreds of microscopic wells, each with different combinations of compounds reacting on a variety of mineral surfaces. The chips would constantly and autonomously monitor the reactions to check for signs that a molecule had gone into runaway self-replication.

Experimenters could cut down the time needed from millions to thousands of years by focusing on combinations of chemicals that are most likely do something interesting. With luck, eventually we will learn enough about how nature works to trim this time down to a few decades.

10,000 YEARS: ARE NATURE'S CONSTANTS TRULY FIXED?

Gerald Gabrielse, physicist at Harvard University

Source: http://rss.sciam.com/click.phdo?i=f63683f4662e281b538b015908b9c9cf

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