Introduction

Astrobiologist Lou Allamandola creates simulated comets in his lab

NASA astrobiologist Lou Allamandola cuts an imposing figure when you pass him in the hallway, but quickly puts you at your ease when you sit down to chat with him. As he describes his research, it dawns on you that this friendly, unpretentious man is making discoveries that may completely alter science's view of the origin of life.

Life is formed from bewilderingly complex molecules, structures of millions of atoms in which each atom must be placed in exactly the right position. But how were these intricate structures ever composed from the simple molecules floating about aimlessly in space? The planet's first single-celled organisms presumably owe their primeval debut to a series of chemical steps that led up to carbon-rich molecules such as amino acids.

As participants in the NASA Astrobiology Institute, Lou and his colleagues Scott Sandford, Max Bernstein, Jason Dworkin and others study the possibility that the building blocks of life were brought to Earth by comets. In their facilities at the Astrochemistry Laboratory at NASA Ames Research Center in California, the team creates simulated comets and interstellar dust grains to study their chemistry.

Dirty snowball Comet Halley begins to glow as it nears the Sun

Most of the time, comets are just chunks of ice and dust with no tail, dirty snowballs orbiting the Sun in the outer solar system. The luminous tail that we’re all familiar with emerges only when the comet nears the Sun and reacts with solar wind and radiation.

Comets and solar systems form in clouds of gas and dust

Comets got their start, just like the planets, in the cloud of gas and dust that condensed to form our solar system. Clouds like these abound throughout the universe. Telescopic observations of them indicate the presence of simple molecules such as water, methanol, carbon dioxide, and ammonia.

The sample chamber recreates the conditions of deep space

Lou and company take these materials, freeze them, and make a comet out of them. Then they simulate the conditions of deep space.

They begin by placing chemical compounds in a shoebox-sized metal sample chamber that creates a vacuum similar to space. "We start with the simplest molecules you can imagine. Then we freeze it to almost zero." That's absolute zero, or -273° Celsius (-460° Farenheit), the coldest anything can be. The compounds freeze into ices. Then the team bombards the ices with the same ultraviolet radiation that permeates deep space.

Page 1 - Introduction
Page 2 - Creating organic compounds
Page 3 - Droplets