A compound and a B3 were found on the asteroid
How Did Amino Acids Come From Space? A Cosmic Ice Laboratory Study of the Distribution of Materials Found in Interstellar Clouds and Asteroids
Some astronomers think life’s heritage must have begun off-planet, because amino acids have been discovered in meteorites, celestial time capsules composed of the same primitive materials from which our solar system formed. (A meteorite is a fragment of an asteroid or any other space rock that has fallen to Earth.) But despite their best efforts, scientists can’t pin down exactly how these molecules got there. Experiments in the lab can’t reproduce what’s found in nature.
A team of researchers at NASA’s Cosmic Ice Laboratory set out to investigate this discrepancy by simulating the chemical activities of interstellar molecular clouds and asteroids, two places known to form amino acids. While they didn’t solve the mystery, the results they published in early January hint that something complicated is happening to produce the distribution of materials found in meteorites.
Yet these molecules by themselves—and even the proteins they form—are not life, any more than a silicon wafer alone is a computer, says study co-author Jason Dworkin, an astronomer at NASA Goddard Space Flight Center. He says it’s a necessity if the wafer has a power supply and software to let it do something. The true seeds of life must be capable of carrying out characteristic functions like replicating and passing down genetic material to offspring.
Ural, a building block of the ribonucleic acid, and vitamins B3 and niacin were found in the samples from two different locations on the asteroid.
Uracil is a nucleobase, or a nitrogen-containing compound. It’s one of five nucleobases in DNA and RNA, the proteins and molecules that contain genetic information and instructions crucial for the cells of living organisms.
The Hayabusa2 Project: Biological Molecules from Ryugu Asteroid and Their Implications for Extraterrestrial Life
Ryugu is a carbon-rich, diamond-shaped asteroid that measures about 3,000 feet (1 kilometer) wide. Hayabusa2 was the first mission to return a subsurface sample from an asteroid to Earth.
The Japanese Aerospace Exploration Agency mission collected one sample from the asteroid’s surface in February 2019, then fired a copper “bullet” into the asteroid to create a 33-foot (10-meter) wide impact crater. A sample was collected in the summer of 2019. Then, Hayabusa2 flew by Earth and dropped the sample off in Australia in December 2020.
The researchers were able to identify the molecule after they soaked particles in hot water and analyzed them with different methods.
“Other biological molecules were found in the sample as well, including a selection of amino acids, amines and carboxylic acids, which are found in proteins and metabolism, respectively,” Oba said.
It’s also possible that as space rocks smashed into other planets in our solar system, they might have been carrying some of the same building blocks of life.
The concentrations of the molecules in the two samples were different, but that’s likely due to exposure to the harsh environment of space. It’s possible that Ryugu was once part of a larger celestial body, like a comet, before it was broken apart into pieces by collisions with other space objects.
“I cannot say the presence of such ingredients directly leads to the emergence/presence of extraterrestrial life, but at least their components such as amino acids and nucleobases may be present everywhere in space,” Oba said.