사용자:Dotchwood/번역장

위키백과, 우리 모두의 백과사전.

번역_헨리에타 리빗[편집]

헨리에타 스완 리빗
Henrietta Swan Leavitt
리빗의 젊은 시절 사진으로, 큰 목 레이스가 달린 드레스를 입고 짧은 머리를 하고 있으며, 보일듯 말듯한 미소를 머금은 상반신 사진이다
헨리에타 스완 리빗
출생랭카스터
사망케임브릿지
거주지케임브릿지
국적미국인
학력래드클리프 대학교 학사
경력세페이드 변광성 발견, 변광성의 주기-광도 관계 발견
직업계산원, 천문학자
소속하버드 대학교
기타에드워드 찰스 피커링에게 영향

헨리에타 스완 리빗 (1968. 07. 04 – 1921. 12. 12) 은 미국의 천문학자였다. 그녀는 래드클리프 대학교에서 학사학위를 받았고, 1893년 하버드 천문대에서 '계산원'이라는 직업으로 근무하였다. 당시 계산원은 천체관측 유리 플레이트에 나타난 별들의 숫자를 계산하는 고된 직업이었다. 그녀가 겨우 주당 10불의 조수직으로 플레이트 탐구를 하며 정립한 혁신적인 이론은, 이후 에드윈 허블의 작업의 근간이 되었다. 이렇듯 세페이드 변광성의 주기-광도 관계에 대한 리빗의 발견은 근대 천문학의 역사를 급격히 바꾸어 놓았지만, 그러한 성취에도 불구하고 당대에 그녀는 거의 아무런 주목도 받지 못했다.

출생과 교육[편집]

헨리에타 스완 리빗은 회중 교회 목사인 조지 로스웰 리빗[1] 과 그의 부인인 헨리에타 스완 (켄드릭) 사이의 딸로 랭카스터에서 태어났다. 그녀는 17세기 초반 메사추세츠 베이 콜로니에 정착했던 영국 청교도 재단사 존 리빗 집사의 후손이다.[2] (초기 메사추세츠 역사 기록에서, 리빗 가의 영어 표기는 'Levett'으로 나타난다.) 그녀는 오벨린 대학교를 거쳐, 당시에는 '여성을 위한 고등 교육 기관' 이라고 불렸던 래드클리프 대학교에서 1892년 학사 과정을 마쳤다. 그녀는 대학 4학년이 되어서야 천문학 강좌를 수강하는데, 성적은 A– 였다.

Career[편집]

Early photo of ‘Pickering's Harem’, as the group of women computers assembled by Harvard astronomer Edward Charles Pickering was dubbed. The group included Leavitt, Annie Jump Cannon, Williamina Fleming and Antonia Maury

Leavitt began work in 1893 at Harvard College Observatory as one of the women human ‘computers’ brought in by Edward Charles Pickering to measure and catalog the brightness of stars in the observatory's photographic plate collection.[3] (In the early 1900s, women were not allowed to operate telescopes).[4] She noted thousands of variable stars in images of the Magellanic Clouds. In 1908 she published her results in the Annals of the Astronomical Observatory of Harvard College,[5] noting that a few of the variables showed a pattern: brighter ones appeared to have longer periods. After further study, she confirmed in 1912 that the variable stars of greater intrinsic luminosity– actually Cepheid variables– did indeed have longer periods,[6] and the relationship was quite close and predictable.

Leavitt's discovery is known as the 'period-luminosity relationship' which is a curvilinear relationship that becomes a straight line relation between the luminosity and the log of the period. "A straight line can be readily drawn among each of the two series of points corresponding to maxima and minima," Leavitt wrote of her study of 1,777 variable stars recorded on Harvard's photographic plates, "thus showing that there is a simple relation between the brightness of the variable and their periods".[7]

Leavitt used the simplifying assumption that all of the Cepheids in the respective Magellenic Clouds were approximately the same distances from the earth, so the relationship became key in determining Cepheid Scale Distance and absolute magnitudes beyond the realm of parallax measurement, once the absolute distance to one Cepheid could later be determined by astronomers. "Since the variables are probably at nearly the same distance from the Earth, their periods are apparently associated with their actual emission of light, as determined by their mass, density, and surface brightness."[8] This relationship would provide an important yardstick for measuring distances in the Universe, if it could be calibrated. One year after Leavitt reported her results, Ejnar Hertzsprung determined the distance of several Cepheids in the Milky Way, and with this calibration the distance to any Cepheid could be determined.

At the time, it was not clear that there were millions of nebulae that were actually galaxies outside of our Milky Way galaxy. Their distances were too extreme to be measured using parallax and the Cepheid period-luminosity relationship provided the key to estimating these distances. Cepheids were soon detected in other galaxies such as the Andromeda Galaxy (notably by Edwin Hubble in 1923–24). Cepheids were an important part of the evidence that galaxies are far outside of the Milky Way and were key to settling the Great Debate as to the nature of spiral nebulae and whether the Universe was larger than the Milky Way. Our picture of the universe was changed forever, largely because of Leavitt's discovery.

Woman sitting at desk writing, with short hair, long-sleeved white blouse and vest
Henrietta Swan Leavitt– one of several women working in "Pickering's Harem" who made fundamental contributions to astronomy[9]

The accomplishments of Edwin Hubble, renowned American astronomer, were made possible by Leavitt's groundbreaking research and Leavitt's Law. "If Henrietta Leavitt had provided the key to determine the size of the cosmos, then it was Edwin Powell Hubble who inserted it in the lock and provided the observations that allowed it to be turned," wrote David H. and Matthew D.H. Clark in their book Measuring the Cosmos.[10] To his credit, Hubble himself often said that Leavitt deserved the Nobel for her work.[11] Gösta Mittag-Leffler of the Swedish Academy of Sciences had begun paperwork on her nomination in 1924, only to learn that she had died of cancer three years earlier[12] (the Nobel prize cannot be awarded posthumously).

Leavitt worked sporadically during her time at Harvard, often sidelined by health problems and family obligations. An illness contracted after her graduation from Radcliffe College rendered her increasingly deaf.[9] By 1921, when Harlow Shapley took over as director of the observatory, Leavitt was made head of stellar photometry. By the end of that year she had succumbed to cancer, and was buried in the Leavitt family plot at Cambridge Cemetery in Cambridge, Massachusetts.

"Sitting at the top of a gentle hill," writes George Johnson in his biography of Leavitt, "the spot is marked by a tall hexagonal monument, on top of which (cradled on a draped marble pedestal) sits a globe. Her uncle Erasmus Darwin Leavitt and his family are also buried there, along with other Leavitts. A plaque memorializing Henrietta and her two siblings who died so young, Mira and Roswell, is mounted directly below the continent of Australia. Off to one side, and more often visited, are the graves of Henry and William James."[13]

Title page of Leavitt's 1777 Variables in the Magellanic Clouds, Annals of the Harvard College Observatory, 1908

Leavitt was a member of Phi Beta Kappa, the American Association of University Women, the American Astronomical and Astrophysical Society, the American Association for the Advancement of Science, and an honorary member of the American Association of Variable Star Observers. Her early passing was seen as a tragedy by her colleagues for reasons that went beyond her scientific achievements.

In an obituary her colleague, Solon I. Bailey, noted, "She had the happy faculty of appreciating all that was worthy and lovable in others, and was possessed of a nature so full of sunshine that, to her, all of life became beautiful and full of meaning."[14]

Awards and honors[편집]

  • The asteroid 5383 Leavitt and the crater Leavitt on the Moon are named in her honor.
  • Unaware of her death four years prior, the Swedish mathematician Gösta Mittag-Leffler considered nominating her for the 1926 Nobel prize in physics, and wrote to Shapley requesting more information on her work on Cepheid variables, offering to send her his monograph on Sofia Kovalevskaya. Shapley replied, let Mittag-Leffler know that Leavitt had died, and suggested that the true credit belonged to his (Shapley's) interpretation of her findings. She was never nominated, because the Nobel Prize is not awarded posthumously.[15]

Notes[편집]

  1. ↑ Gregory M. Lamb (2005년 7월 5일). “Before computers, there were these humans...”. Christian Science Monitor. 2007년 5월 18일에 확인함. 
  2. ↑ Out of Shadows: Contributions of Twentieth-century Women to Physics, Nina Byers, Gary Williams, Cambridge University Press, 2006, ISBN 0-521-82197-5, 9780521821971
  3. ↑ Leavitt began working for Pickering as a volunteer in 1893. Because she had 'independent means', Pickering did not have to pay her. Later, as a "computer", she was paid $10.50 a week for her work studying photographic plates and deciphering what they meant. Pickering assigned Leavitt to study 'variable stars', whose luminosity varies over time. "Variable stars had been of interest for years," writes noted science author Jeremy Bernstein in The Los Angeles Times, "but when she was studying those plates, I doubt Pickering thought she would make a significant discovery– one that would eventually change astronomy." Story.
  4. ↑ Exploratorium note
  5. ↑ Leavitt, Henrietta S. "1777 Variables in the Magellanic Clouds". Annals of Harvard College Observatory. LX(IV) (1908) 87-110
  6. ↑ Miss Leavitt in Pickering, Edward C. "Periods of 25 Variable Stars in the Small Magellanic Cloud" Harvard College Observatory Circular 173 (1912) 1-3.
  7. ↑ Kerri Malatesta (2010년 7월 16일). “Delta Cephei”. American Association of Variable Star Observers. 
  8. ↑ Periods Of 25 Variable Stars In The Small Magellanic Cloud, Harvard College Observatory Circular 173, 1912, Edward C. Pickering citing Henrietta Leavitt
  9. ↑ 가 나 Hamblin, Jacob Darwin (2005). 《Science in the early twentieth century: an encyclopedia》. ABC-CLIO. 181–184쪽. ISBN 1851096655. 
  10. ↑ David H. Clark; Matthew D.H. Clark (2004). 《Measuring the Cosmos: How Scientists Discovered the Dimensions of the Universe》. Rutgers University Press. ISBN 0813534046. 
  11. ↑ Ventrudo, (2009)
  12. ↑ Singh, Simon (2005). 《Big Bang: The Origin of the Universe》. HarperCollins. ISBN 0007162219. 
  13. ↑ Johnson, p 90
  14. ↑ Johnson, p 28
  15. ↑ Johnson, pp 118–119

References[편집]

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