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Gravitational Waves


This article appeared in the November 3, 2017 edition of the Davis Enterprise.

Gravitational Waves

An artist's rendering of two colliding neutron stars by ESO/L. Calçada/M. Kornmesser.


By Vinita Domier

Special to the Enterprise


On October 16, 2017, scientists announced that USA’s Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and European’s Advanced Virgo jointly detected gravitational waves (GW), and NASA’s Fermi satellite independently detected gamma rays, emanating from the in-spiraling and ultimate collision of highly dense binary neutron stars in the galaxy 130 light-years away.


The announcement was doubly historic as not only was the 100-second long GW170817 the first direct detection of GW resulting from the spiral dance and eventual cataclysmic merger of two neutron stars, but it was also the first time that electromagnetic gamma ray bursts (GRB170817A) produced in the collision were also detected 1.7 seconds later.


The resulting kilonova was also observed by ~70 ground-based and space-based telescopes in all the electromagnetic frequencies. They detected the presence of heavy elements like gold and palladium in the ejecta of the neutron stars, confirming that half of the elements heavier than iron are manufactured in the extreme temperatures and pressures of neutron star kilonovae.


Most of what we know about the universe thus far – from the Big Bang 13.8 billion years ago to the present – has been through the observations and deductions of electromagnetic waves (EMW) ranging from the lowest-frequencies radio waves to the highest-frequencies gamma rays, and from the detections of neutrinos and cosmic rays. The September 2015 direct detection of the highly elusive GW by the twin LIGO detectors, over a century after Albert Einstein predicted their existence in his General Theory of Relativity, provided scientists with another revolutionary way to study and decipher the universe.


GW are ripples in spacetime that are smaller than the size of a proton by the time they reach earth. Astronomers study the universe by ‘seeing’ EMW that travel at the speed of light, but they can get reflected or absorbed by intervening matter. Now they can ‘hear’ GW that also travel at the speed of light but pass through intervening matter virtually unchanged. Akin to EMW, amplitudes of GW attenuate with increasing distance of detector and source, and their frequencies are redshifted or blueshifted due to the relative velocities of source and detector, just like EW.


Join the Davis Astronomy Club on Saturday, November 4, starting at 7pm at the Explorit Science Center (3141 5th Street, Davis) when we will discuss gravitational waves and how they are detected. We will also talk about the fiery end of the 20-year Cassini mission to Saturn. Everyone is invited to the free meeting indoors, followed by a star party outdoors (weather permitting).



Explorit’s coming events:


●      Visit our NEW Feathers exhibition! Explorit’s Exploration Gallery is open to the public every Monday, 9:00 a.m. to 1:00 p.m., every Wednesday, Friday, Saturday and Sunday, 1:00-5:00 p.m.  Admission is $5.00 per person; Explorit members, teachers and children 2 and under are free.

●      Explorit is entering into its annual fundraising drive. Now more than ever, we need science education. Your donations help Explorit serve our community with exhibits, activities and educational outreach programs in 15 surrounding counties. Sponsor a program by making a gift at, or call us for more details.



Explorit Science Center is located at 3141 5th St. For more information call (530) 756-0191 or visit, or “like” us on Facebook at

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