Dennis Stewart November Smu Modern Physics 1 Outline for this talk Einstein Einsteins Contribution Joseph Weber LIGO The Machine and How it works The Chrip Conclusion 2 Albert Einstein ID: 556408
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Slide1
Gravity Waves
Dennis Stewart
NovemberSmuModern Physics
1Slide2
Outline for this talk
Einstein
Einsteins Contribution
Joseph Weber
LIGO
The Machine and How it works
The ChripConclusion
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Albert Einstein
German Born Theoretical Physicist (1879-1955)
Developed the General Theory of RelativityBest known for his mass energy equivalent principle E=mc^2
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A 100 year old prediction thanks to GR
Developed between 1907 and 1915
Explains the cause of space-time warpingGravitational waves were predicted in 1916 as ‘ripples’
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Joseph Weber
Studied gravitational radiation
Developed ‘Weber Bars’ in the 60’sApollo 17 Lunar MissionNever produced solid evidence
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LIGO
Laser Interferometer Gravitational-Wave ObservatorySlide7
Inside LIGO
To spot a signal, LIGO uses a special mirror to split a beam of laser light and sends the beams down
two 4-kilometer-long arms, at a 90 degree angle to each other. After ricocheting back and forth 400 times, turning each beam’s journey into a
1,600 kilometer round-trip
, the light recombines near its source.
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The Signal
Produced by the inspired and merger of the first observation of such black holes Each with a mass 25X greater than our sun which is 1.989 × 10^30 kgTravel at the speed of lightstretching spacetime in the plane perpendicular to the direction they’re moving in
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The experiment is designed so that, in normal conditions, the
light waves
cancel
one another out when they recombine,
sending no light signal to the nearby detector.
But a gravitational wave
stretches
one tube while
squeezing
the other, altering the distance the two beams travel relative to each other.
Because of this difference in distance
, the recombining
waves are no longer perfectly aligned
and therefore don’t cancel out. The detector picks up a faint glow, signaling a passing wave.
How Detection WorksSlide10
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http://physics.aps.org/assets/8cbf3dfb-7849-485b-8626-1276bc044ddf/video1.mp4Slide11
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100 Years LaterSlide12
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Measurements Used
Masses of BlackholesSlide13
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Measurements Used
Merger RateSlide14
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Measurements Used
Periastron DistancesSlide15
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Measurements Used
Maximum luminosity distance (
DL
)
Redshift (
z
)
On the right a measure for the surveyed volume (V[bar]_c) for the initial LIGO/Virgo detectors, the current aLIGO, and future expectationsSlide16
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The ChirpSlide17
In Closing
For the first time we have observational evidence that BBH systems actually form in nature, with properties such that they merge in the local universe.
We are looking forward to the development of GW astronomy as a new way of probing the universe.17Slide18
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The End!Slide19
Sources
http://www.nature.com/news/einstein-s-gravitational-waves-found-at-last-1.19361
http://physics.aps.org/articles/v9/17http://iopscience.iop.org/article/10.3847/2041-8205/818/2/L22/meta;jsessionid=9B49F1CD55E9BBF9ADD8F5261D7C3DB4.c1.iopscience.cld.iop.org\http://iopscience.iop.org/article/10.1088/0264-9381/32/7/074001/metal
https://physics.aps.org/story/v16/st19
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