Some scientists suspect that amino acids hitchhiked to Earth on meteorites or asteroids.

Us scientists have found in a new study that an amino acid called carbamic acid can form at extremely cold temperatures, suggesting it has the potential to be created on ice in deep space. The paper appears in the Nov. 29 issue of ACS Central Science, a journal of the American Chemical Society.

Amino acids are the building blocks of proteins and are essential for life on Earth. Some scientists suspect they may have been transported to Earth by meteorites or asteroids.

In fact, some amino acids, such as carbonic acid and glycine, have been found floating in space over the past few decades, but exactly how these molecules form remains unknown.

Now, Ralph Kaiser's team at the University of Hawaii at Manoa has discovered that carbamic acid, a key amino acid, can be produced through a reaction on a deep-space ice cube.

Carbamic acid is a simple amino acid that is a precursor to more complex compounds that occur naturally in various enzymes. To explore whether carbamic acid can form in the extremely cold conditions of space, the team placed carbamic acid reactants carbon dioxide and ammonia in a refrigerator that could be cooled to -268 ° C.

The researchers then let the temperature rise slowly, and when the temperature reached -211 ° C, carbon dioxide and ammonia reacted to form carbamic acid, providing evidence that the building blocks of life may have originated in space.

They also found that ammonium carbamate is produced at -234 ° C. Ammonium carbamate is an intermediate product of urea production process in chemical industry, and urea can be formed by heating and dehydration.

These formation conditions are similar to what scientists see in molecular clouds around young stars and planets, Kaiser said, and it's possible that carbamic acid and ammonium carbamate first appeared on ice in these regions.

Eventually, they fall into the arms of meteorites or asteroids and travel to the solar system or other star systems.

Researchers hope the findings will help in the search for amino acids in space, which instruments such as the James Webb Space Telescope may be able to accomplish. By finding out where and under what conditions these molecular precursors formed, it is also possible to predict the formation of life.