New research shows that interplanetary dust particles from comets, asteroids, and leftover debris from the birth of the solar system, could have helped jump-start life on Earth and other terrestrial planets.
Researchers from the University of Hawaiʻi at Mānoa’s School of Ocean and Earth Science and Technology (SOEST), Lawrence Livermore National Laboratory, Lawrence Berkeley National Laboratory, and University of California – Berkeley discovered that interplanetary dust particles (IDPs) could deliver water and organics to the Earth and other terrestrial planets.
Interplanetary dust, dust that has come from comets, asteroids, and leftover debris from the birth of the solar system, continually rains down on the Earth and other Solar System bodies. These particles are bombarded by solar wind, predominately hydrogen ions. This ion bombardment knocks the atoms out of order in the silicate mineral crystal and leaves behind oxygen that is more available to react with hydrogen, for example, to create water molecules.
“It is a thrilling possibility that this influx of dust has acted as a continuous rainfall of little reaction vessels containing both the water and organics needed for the eventual origin of life on Earth and possibly Mars,” said Hope Ishii, new Associate Researcher in the Hawaiʻi Institute of Geophysics and Planetology (HIGP) at UH Mānoa’s SOEST and co-author of the study. This mechanism of delivering both water and organics simultaneously would also work for exoplanets, worlds that orbit other stars. These raw ingredients of dust and hydrogen ions from their parent star would allow the process to happen in almost any planetary system.
Implications of this work are potentially huge: Airless bodies in space such as asteroids and the Moon, with ubiquitous silicate minerals, are constantly being exposed to solar wind irradiation that can generate water. In fact, this mechanism of water formation would help explain remotely sensed data of the Moon, which discovered OH and preliminary water, and possibly explains the source of water ice in permanently shadowed regions of the Moon.
“Perhaps more exciting,” said Hope Ishii, Associate Researcher in HIGP and co-author of the study, “interplanetary dust, especially dust from primitive asteroids and comets, has long been known to carry organic carbon species that survive entering the Earth’s atmosphere, and we have now demonstrated that it also carries solar-wind-generated water. So we have shown for the first time that water and organics can be delivered together.”
It has been known since the Apollo-era, when astronauts brought back rocks and soil from the Moon, that solar wind causes the chemical makeup of the dust’s surface layer to change. Hence, the idea that solar wind irradiation might produce water-species has been around since then, but whether it actually does produce water has been debated. The reasons for the uncertainty are that the amount of water produced is small and it is localized in very thin rims on the surfaces of silicate minerals so that older analytical techniques were unable to confirm the presence of water.
Using a state-of-the-art transmission electron microscope, the scientists have now actually detected water produced by solar-wind irradiation in the space-weathered rims on silicate minerals in interplanetary dust particles. Futher, on the bases of laboratory-irradiated minerals that have similar amorphous rims, they were able to conclude that the water forms from the interaction of solar wind hydrogen ions (H+) with oxygen in the silicate mineral grains.
This recent work does not suggest how much water may have been delivered to Earth in this manner from IDPs.
“In no way do we suggest that it was sufficient to form oceans, for example,” said Ishii. “However, the relevance of our work is not the origin of the Earth’s oceans but that we have shown continuous, co-delivery of water and organics intimately intermixed.”
In future work, the scientists will attempt to estimate water abundances delivered to Earth by IDPs. Further, they will explore in more detail what other organic (carbon-based) and inorganic species are present in the water in the vesicles in interplanetary dust rims.
Publication: John P. Bradley, et al., “Detection of solar wind-produced water in irradiated rims on silicate minerals,” PNAS, 2014; doi: 10.1073/pnas.1320115111
Source: University of Hawaiʻi at Mānoa
Show me a meteorite made of compost or bat s***?
Accretion of extraterrestrial matter has long been of interest as a source
of pre-biotic organic carbon for the origin of life on Earth (Oró, 1961;
Sagan, 1974; Lewis et al., 1979; Anders, 1989; Pepin, 1991; Huebner
and Boice, 1992; Delsemme, 1992; Chyba and Sagan, 1992, 1998;
Oberbeck and Aggarwal, 1993; Chang 1993, Whittet, 1997; Oró and
Lazcano, 1998). Most organic carbon is thought to be accreted by
impacts of comets and primitive asteroids (Oró, 1961; Chyba et al.,
1990). However, the high-speed impacts are expected to be so energetic
that the ensuing fireball destroys virtually all molecular species in the
impacting object and subsequent synthesis upon cooling in a CO2 rich
atmosphere is not efficient (McKay and Borucki, 1997; Chyba and
Sagan, 1998). Moreover, such impacts are infrequent and have strong
perturbing effects on the pre-biotic environment at the time of delivery
(Maher and Stevenson, 1988; McKinnon, 1989; Chyba, 1993).
Accretion of meteoroids is a more gentle and continuous mechanism
for delivery of organic carbon species, especially in the case of the
Interplanetary Dust Particles (IDP) that are collected mostly intact in the
Earth's atmosphere. Among this collected debris of small solar system
bodies there are chondritic IDPs with organic carbon abundances of
about 10 mass percent on average (Anders, 1989; Gibson, 1992). The
organic carbon contains complex aromatic molecules up to 500 a.m.u.
(Clemett et al. 1993). However, all IDPs represent a small fraction (< 8
%) of the incoming mass, while low encounter velocities favor asteroidal
particles that are relatively poor in organic carbon compared to cometary
matter (Bradley et al., 1988). Comet Halley’s dust has been measured to
contain up to 50 mass percent refractory organics (Krueger and Kissel,
1987; Greenberg, 2000).
Show me a meteorite made of compost or bat s***?
I think by organic matter they're talking bacteria lol