A novel, gum-like substance – previously unobserved in extraterrestrial environments – is believed to have originated during the nascent stages of our Solar System when the parent asteroid of Bennu underwent thermal processing. This material, initially yielding and pliable but subsequently solidified, is a relic of ancient “space gum” comprising polymer-like constituents exceptionally abundant in nitrogen and oxygen. The presence of such intricate molecular structures could potentially represent foundational chemical precursors essential for the emergence of life on Earth. Their discovery within the uncontaminated samples retrieved from Bennu holds significant implications for scientific research into abiogenesis and the potential for extraterrestrial life.
Electron microscopy of a particle from the sample from Bennu. Image credit: Sandford et al., doi: 10.1038/s41550-025-02694-5.
The primordial asteroid that gave rise to Bennu coalesced from the constituents of the Solar Nebula – the vast, swirling expanse of gas and dust from which the Solar System evolved – and contained a diverse array of minerals and frozen volatiles.
As this asteroid experienced heating through natural radioactive decay, a chemical compound known as carbamate was synthesized via a reaction involving ammonia and carbon dioxide.
Although carbamate is soluble in water, it persisted long enough to undergo polymerization. This process involved its reaction with itself and other molecular entities, leading to the formation of larger, more complex chains that were resistant to water.
This observation suggests that the formation occurred prior to the parent body reaching a temperature sufficient to develop an aqueous environment.
“In examining this peculiar material, we may be observing, with considerable probability, one of the earliest instances of material alteration within this rocky body,” stated Dr. Scott Sandford, a researcher affiliated with NASA’s Ames Research Center.
“On this ancient asteroid, which formed during the initial epochs of the Solar System’s existence, we are essentially witnessing events occurring at the very genesis of cosmic evolution.”
Within the scope of the research, the investigators meticulously analyzed the distinct characteristics of Bennu’s gum-like substance.
As the detailed examination progressed, evidence emerged indicating that the material had been deposited in stratified layers upon icy particles and mineral grains present within the asteroid.
Furthermore, its texture was found to be yielding – a malleable consistency comparable to used chewing gum or a soft plastic composite.
Indeed, during their laboratory work with the collected samples, the research team observed that the anomalous material exhibited pliability and indentation when subjected to applied pressure.
The substance possessed a translucent quality, and exposure to radiation rendered it brittle, analogous to a patio chair left outdoors for multiple seasons, succumbing to the effects of prolonged sunlight.
“A review of its chemical composition reveals the presence of similar chemical functional groups found in terrestrial polyurethanes, thereby positioning this material from Bennu as a form of ‘extraterrestrial plastic’,” Dr. Sandford elaborated.
“However, the ancient asteroid material is not a straightforward polyurethane, which is characterized by an ordered polymeric structure.”
“This particular substance exhibits more disordered connections and a compositional variability of elements that differs from one particle to another.”
The research team’s discoveries were officially disseminated on December 2, 2025, within the esteemed journal Nature Astronomy.
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S.A. Sandford et al. Nitrogen- and oxygen-rich organic material indicative of polymerization in pre-aqueous cryochemistry on Bennu’s parent body. Nat Astron, published online December 2, 2025; doi: 10.1038/s41550-025-02694-5
