A new experiment simulating conditions in deep space reveals that the complex building blocks of life could have been created on icy interplanetary dust and then carried to Earth, providing raw materials for the organic chemistry needed for life.

The experimenters showed that conditions in space are capable of creating complex dipeptides – linked pairs of amino acids – that are essential building blocks shared by all living things. The discovery raises the possibility that these molecules were brought to Earth on a comet or possibly meteorites, catalyzing the formation of proteins (polypeptides), enzymes and even more complex molecules, such as sugars, that are necessary for life.

While scientists have discovered basic organic molecules, such as amino acids, in numerous meteorites that have fallen to Earth, they have been unable to find the more complex molecular structures that are prerequisites for our planet’s biology. As a result, scientists have always assumed that the really complicated chemistry of life must have originated in Earth’s early oceans.

In an ultra-high vacuum chamber chilled to 10 degrees above absolute zero (10 Kelvin), researchers simulated an icy snowball in space including carbon dioxide, ammonia and various hydrocarbons such as methane, ethane and propane. When zapped with high-energy electrons to simulate the cosmic rays in space, the chemicals reacted to form complex, organic compounds, specifically dipeptides. The organic residues were then analyzed with an instrument designed for ultrasensitive detection and identification of small organic molecules in the solar system. The analysis revealed the presence of complex molecules – nine different amino acids and at least two dipeptides – capable of catalyzing biological evolution on earth.

Astronomers have detected about 180 molecules in interstellar space, from simple ones like carbon monoxide (one atom of carbon and one of oxygen) to complex species like buckminsterfullerene (sixty atoms of carbon) or anthracene (fourteen atoms of carbon and ten of hydrogen). These chemicals are found in a wide variety of environments in the galaxy, and in principle can provide the backbone for the subsequent production of the molecules essential to life.

The search for molecules associated with life however, for example simple sugars, has been less successful. The simplest sugar is glycolaldehyde (HCOCH2OH). It has been spotted in only two extreme places so far: a massive dense molecular cloud near the galactic center, and a dense core of gas and dust that is forming massive stars. It has not even been found in solar system comets, which are thought to contain samples of material dating from the early solar nebula.

There is now a report of glycolaldehyde in the material around a newly developing star of approximately solar mass. Astronomer Tyler Bourke and five colleagues used the new Atacama Large Millimeter Array (ALMA) facility in Chile to observe the protostar IRAS16293-2422, located about 400 light-years away. They find thirteen different lines characteristic of this molecule, and their analysis finds that the gas is warm (about 200-300 kelvin) and probably part of a large system of material flowing in towards the star as it grows and develops a system of planets. Although the exact mechanism(s) that produce the glycolaldehyde are uncertain, the new results help confirm that molecules associated with life exist in normal environments around young, solar-mass stars.

More:

• Sweet Result from ALMA
• Sweet Building Blocks of Life Found Around Young Star
• Sugar Found In Space: A Sign of Life?
• Sugar spotted around star

Though life is a complicated brew, some of its ingredients can be plucked from Earth’s backyard instead of being imported from more distant interstellar fields.

In a new study, scientists suggest that complex organic molecules — such as the amino acids that build proteins and the ringed bases that form nucleic acids — grow on the icy dust grains that lived in the infant solar system. All it takes are high-energy ultraviolet photons to provoke the rearrangement of chemical elements in the grains’ frozen sheaths.

If making these organic ingredients happens this readily, then exoplanetary systems are probably seeded with the same fertile, organic pastures. “Anywhere you have ice and high-energy, ultraviolet radiation, this process is going to take place. And those are both pretty common in the universe,” says Dante Lauretta, a planetary scientist at the University of Arizona.

More:

• Organics Probably Formed Easily in Early Solar System
• Organic compounds found in proto-planetary disks