Artist's rendering of the LISA Pathfinder space probe approaching solar orbit.
(Image Source: European Space Agency / C. Carreau)
By Glenn A. Walsh
Reporting for SpaceWatchtower
A laser space probe, designed as a space-based, proof-of-concept mission for finding gravitational-waves, has now been used to map microscopic dust shed by comets and asteroids. This is a clear demonstration that 'empty space' between stars and planetary bodies is not really all that empty!
Due to the space probe's extreme sensitivity, a requirement for the detection of gravitational-waves, NASA scientists have used data from the European Space Agency's (ESA) LISA Pathfinder spacecraft to detect 54 micrometeroid impacts on the spacecraft during the 2015 to 2017 time-frame. The micrometeroids detected are extremely small.
Their masses are measured in micrograms and are similar in size to grains of sand. This cosmic dust was actually smaller than the dust from comets that cause most meteor showers. However, they hit the spacecraft at approximate speeds of 40,000 miles-per-hour / 64,000 kilometers-per-hour, which could injure a spacecraft if the particles had been larger.
NASA scientists, headed by Ira Thorpe of the Goddard Space Flight Center in Greenbelt, Maryland, used modeling to determine where the micrometeroids originate. Their research was published in the September issue of the Astrophysical Journal, the prestigious publication founded in 1895 by George Ellery Hale, who would become Director of the Mount Wilson Observatory, and James E. Keeler, Director of the Allegheny Observatory.
The NASA scientists found that most of the micrometeroids come from short-period comets, whose orbits are determined by Jupiter; this is consistent with current ideas regarding micrometeroids near Earth. However, LISA Pathfinder also detected dust from some long-period comets, similar to the famous Halley's Comet.
These results will help in predicting impact risks for current and future spacecraft. They may also help in the understanding of the physics of planet formation.
Launched on 2015 December 3, the LISA Pathfinder mission was to prove the feasibility of a space-based laser interferometer system for finding ripples in space-time caused by, for instance, the merger of black holes. Led by the European Space Agency, with contributions from NASA, the mission was used to test technologies necessary for a space-based observatory that would do what the ground-based LIGO (Laser Interferometer Gravitational-Wave Observatory) has done from the Earth.
LIGO is limited by seismic, thermal, and other sources of noise present on the Earth. It is hoped that a space-based system, without these limitations, would be even more sensitive and find even more gravitational-waves.
The main LISA (Laser Interferometer Space Antenna) mission, expected to be launched around 2034, would consist of a constellation of three spacecraft arranged in an equilateral triangle with sides 1.55 million statute miles / 2.5 million kilometers long, in an orbit around the Sun. By precisely monitoring the distances between each satellite, more ripples in space-time should be detected.
Internet Links to Additional Information ---
LISA Pathfinder Spacecraft: Link >>> https://en.wikipedia.org/wiki/LISA_Pathfinder
LISA Spacecraft (launch in 2034): Link >>> https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Antenna
LIGO Ground-Based Observatory: Link >>> https://en.wikipedia.org/wiki/LIGO
Micrometeroid: Link >>> https://en.wikipedia.org/wiki/Micrometeoroid
Related Blog-Posts ---
"Physics Nobel Prize Awarded to Developers of Laser Observatory." Sat., 2017 Oct. 7.
"Laser Gravitational-Wave Observatory Researchers Receive 2 Awards. Sun., 2016 June 5.
Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
Saturday, 2019 December 7.
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Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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