WordNet
- shining intermittently with a sparkling light; "twinkling stars"
PrepTutorEJDIC
- きらきら光る / またたく間,瞬間
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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/08/21 20:40:23」(JST)
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Twinkling, or scintillation, is a generic term for variations in apparent brightness or position of a distant luminous object viewed through a medium.[1] If the object lies outside the Earth's atmosphere, as in the case of stars and planets, the phenomenon is termed astronomical scintillation; within the atmosphere, the phenomenon is termed terrestrial scintillation.[2] As one of the three principal factors governing astronomical seeing, atmospheric twinkling is defined as variations in illuminance only. Twinkling does not cause images of planets to flicker.[3][4] Most scintillation effects are caused by anomalous refraction caused by small-scale fluctuations in air density usually related to temperature gradients.[5][6] Scintillation effects are always much more pronounced near the horizon than near the zenith (straight up).[7] Atmospheric twinkling is measured quantitatively using a scintillometer.[8] The effects of twinkling are reduced by using a larger receiver aperture. This effect is known as aperture averaging.[9][10]
Planetary scintillation[edit source | edit]
Light from planets, stars and other astronomical objects are also likely to twinkle.[11]
Stars twinkle because they are so far from Earth that they appear as point sources of light easily disturbed by Earth's atmospheric turbulence which acts like lenses and prisms diverting the light's path. Scintillation occurs because astronomical objects are points of light so small that they fall upon only one rod at a time in the human retina. As the point of light moves from rod to rod to rod, the star will "twinkle". Large astronomical objects closer to Earth, like the Moon and other planets, encompass many points in space and can be resolved as objects with observable diameters. With multiple observed points of light traversing the atmosphere, their light's deviations average out and the viewer perceives less variation in light coming from them.[12][13]
See also[edit source | edit]
- Scintillation (disambiguation)
- Astronomical seeing
- Earth's atmosphere
- Interplanetary scintillation
- Observational astronomy
- Twinkle Twinkle Little Star
References[edit source | edit]
- ^ Wang,Ting-I; Williams, Donn; "Scintillation technology bests NIST", InTech, May 1, 2005
- ^ " NASA Aerospace Science and Technology Dictionary", NASA.gov
- ^ Kenyon, S.L.; Lawrence, M. et al; "Atmospheric Scintillation at Dome C, Antarctica", Astronomical Society of the Pacific 118 924-932
- ^ Ellison, M. W. (1952). "Why do Stars Twinkle?". Irish Astronomical Journal 2 (1): 5–8. Bibcode:1952IrAJ....2....5E.
- ^ Sofieva, V. F.; Sofieva, A.S.; et al "Reconstruction of internal gravity wave and turbulence parameters in the stratosphere using GOMOS scintillation measurements" Journal of Geophysical Research 112
- ^ VanCleave, Janice; "Stellar Scintillation: Twinkling Stars" JVC's Science Fair Projects, May 2, 2010
- ^ "Scintillation or Atmospheric Boil", noaa.gov
- ^ Chun, M.; Avila, R; "Turbulence profiling using a scanning scintillometer", Astronomical Site Evaluation in the Visible and Radio Range, Astronomical Society of the Pacific 266:72-78
- ^ Perlot,.N.; Fritzsche, D. "Aperture-Averaging - Theory and Measurements", elib - Electronic Library
- ^ Andrews, C.; Phillips, R.L; Hopen, C. (2000). "Aperture averaging of optical scintillations". Waves in Random and Complex Media (Taylor & Francis) 10 (1): 53–70.
- ^ Wheelon, Albert D. "Electromagnetic Scintillation: Volume 2, Weak Scattering", Cambridge University Press, Jul 31, 2003
- ^ Graham, John A. "Why do stars twinkle?" Scientific American, October 2005
- ^ Byrd, Deborah; "Why don’t planets twinkle as stars do?", Earthsky, October 24, 2005
UpToDate Contents
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English Journal
- High-pitch, dual-source chest computed tomography angiography without electrocardiographic synchronization: evaluation of cardiac motion artifacts on pulmonary circulation.
- Tacelli N1, Darchis C, Pontana F, Faivre JB, Deken V, Duhamel A, Murphy C, Remy J, Remy-Jardin M.Author information 1*Department of Thoracic Imaging, Hospital Calmette †Department of Medical Statistics, University of Lille Nord de France, Lille, France.AbstractPURPOSE: To evaluate the frequency and severity of cardiac motion artifacts on high-pitch, dual-source computed tomography angiograms of the chest.
- Journal of thoracic imaging.J Thorac Imaging.2013 Nov;28(6):376-82. doi: 10.1097/RTI.0b013e31828d4209.
- PURPOSE: To evaluate the frequency and severity of cardiac motion artifacts on high-pitch, dual-source computed tomography angiograms of the chest.MATERIALS AND METHODS: One hundred consecutive patients underwent a non-electrocardiogram-gated, dual-source chest computed tomography examination with h
- PMID 23615574
- Astrophysics: Twinkling stars.
- Christensen-Dalsgaard J.
- Nature.Nature.2013 Aug 22;500(7463):405-6. doi: 10.1038/500405a.
- PMID 23969453
- Sonographic diagnosis of symptomatic ureteral calculi: usefulness of the twinkling artifact.
- Ripollés T1, Martínez-Pérez MJ, Vizuete J, Miralles S, Delgado F, Pastor-Navarro T.Author information 1Department of Radiology, Hospital Universitario Dr. Peset, 90 Gaspar Aguilar Avenue, 46017, Valencia, Spain. ripolles_tom@gva.esAbstractPURPOSE: Our aim was to analyze the value of ultrasound using the twinkling sign in the diagnosis of ureteral stones in patients with renal colic in the emergency setting.
- Abdominal imaging.Abdom Imaging.2013 Aug;38(4):863-9. doi: 10.1007/s00261-012-9946-7.
- PURPOSE: Our aim was to analyze the value of ultrasound using the twinkling sign in the diagnosis of ureteral stones in patients with renal colic in the emergency setting.MATERIALS AND METHODS: Prospective study of 100 patients with suspected renal colic who underwent an US examination, including co
- PMID 23011549
Japanese Journal
- 環境外乱下における軟組織中に内包される微細石灰化からの超音波エコーの観察 (超音波)
- 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 115(102), 1-5, 2015-06-19
- NAID 40020523440
- Fundamental study of numerical simulation of ultrasound wave propagation in microcalcification for analysis of twinkling sign
- カラードプラ法でtwinkling artifactを呈した乳房コレステリン肉芽腫の1例
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