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.
Link >>> http://spacewatchtower.blogspot.com/2017/10/physics-nobel-prize-awarded-to.html
"Laser Gravitational-Wave Observatory Researchers Receive 2 Awards. Sun., 2016 June 5.
Link >>> http://spacewatchtower.blogspot.com/2016/06/laser-gravitational-wave-observatory.html
Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
Saturday, 2019 December 7.
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gaw
Glenn A. Walsh, Informal Science Educator & Communicator:
< http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: < http://buhlplanetarium.tripod.com/fotz/ >
SpaceWatchtower Editor / Author: < http://spacewatchtower.blogspot.com/ >
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.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
< http://www.planetarium.
* Adler Planetarium, Chicago:
< http://adlerplanetarium.
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
< http://www.andrewcarnegie.
Albert Einstein proposed the General Theory of Relativity in 1915. After an experiment during a solar eclipse, scientists confirmed the theory in 1919. This 1934 photograph shows Dr. Einstein (right) visiting the exhibit booth of the Amateur Astronomers Association of Pittsburgh (AAAP) at the annual conference of the American Association for the Advancement of Science in Pittsburgh. To the front-left of Dr. Einstein is Leo J. Scanlon, AAAP Co-Founder (1929), constructor of the world's first all-aluminum, astronomical observatory dome (1930), and one of the first two Buhl Planetarium lecturers (1939).
