First explained by Joshua Childrey in 1661 as sunlight scattered in our direction by dust particles in the solar system, the source of that dust was long debated. In a paper to appear in the April 20 issue of The Astrophysical Journal, David Nesvorny and Peter Jenniskens put the stake in asteroids. More than 85 percent of the dust, they conclude, originated from Jupiter Family comets, not asteroids.
"This is the first fully dynamical model of the zodiacal cloud," says planetary scientist Nesvorny of the Southwest Research Institute in Boulder, Colo. "We find that the dust of asteroids is not stirred up enough over its lifetime to make the zodiacal dust cloud as thick as observed. Only the dust of short-period comets is scattered enough by Jupiter to do so."
This result confirms what meteor astronomer Jenniskens of the SETI Institute in Mountain View, Calif., had long suspected. An expert on meteor showers, he had noticed that most consist of dust moving in orbits similar to those of Jupiter Family comets, but without having active dust-oozing comets associated with them.
Instead, Jenniskens discovered a dormant comet in the Quadrantid meteor shower in 2003 and has since identified a number of other such parent bodies. While most are inactive in their present orbit around the Sun, all have in common that they broke apart violently at some point in time in the past few thousand years, creating dust streams that now have migrated into Earth's path.
Nesvorny and Jenniskens, with the help of Harold Levison and William Bottke of the Southwest Research Institute, David Vokrouhlicky of the Institute of Astronomy at Charles University in Prague, and Matthieu Gounelle of the Natural History Museum in Paris, demonstrated that these comet disruptions can account for the observed thickness of the dust layer in the zodiacal cloud.
In doing so, they solved another mystery. It was long known that snow in Antarctica is laced with micro-meteorites, some 80 to 90 percent of which have a peculiar primitive composition, rare among the larger meteorites that we know originated from asteroids. Instead, Nesvorny and Jenniskens suggest that most antarctic micro-meteorites are pieces of comets. According to their calculations, cometary grains dive into Earth's atmosphere at entry speeds low enough for them to survive, reach the ground, and be picked up later by a curious micro-meteorite hunter.
This work was funded by the NASA Planetary Geology and Geophysics Program and the NASA Planetary Astronomy programs.
Maria Martinez | EurekAlert!
One-way roads for spin currents
23.05.2018 | Singapore University of Technology and Design
Tunable diamond string may hold key to quantum memory
23.05.2018 | Harvard John A. Paulson School of Engineering and Applied Sciences
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Life Sciences
23.05.2018 | Life Sciences
23.05.2018 | Physics and Astronomy