File:Cosmic distance ladder.jpg

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摘要

描述Cosmic distance ladder.jpg	English: For the calibration of relatively short distances the team observed Cepheid variables. These are pulsating stars which fade and brighten at rates that are proportional to their true brightness and this property allows astronomers to determine their distances. The researchers calibrated the distances to the Cepheids using a basic geometrical technique called parallax. With Hubble’s sharp-eyed Wide Field Camera 3 (WFC3), they extended the parallax measurements further than previously possible, across the Milky Way galaxy. To get accurate distances to nearby galaxies, the team then looked for galaxies containing both Cepheids and Type Ia supernovae. Type Ia supernovae always have the same intrinsic brightness and are also bright enough to be seen at relatively large distances. By comparing the observed brightness of both types of stars in those nearby galaxies, the team could then accurately measure the true brightness of the supernova. Using this calibrated rung on the distance ladder the accurate distance to additional 300 type Ia supernovae in far-flung galaxies was calculated. They compare those distance measurements with how the light from the supernovae is stretched to longer wavelengths by the expansion of space. Finally, they use these two values to calculate how fast the universe expands with time, called the Hubble constant.
日期	2016年6月2日, 17:30:00
来源	http://www.spacetelescope.org/images/heic1611a/
作者	NASA,ESA, A. Feild (STScI), and A. Riess (STScI/JHU)

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	日期/时间	缩⁠略⁠图	大小	用户	备注
当前	2016年6月3日 (五) 10:04		1,280 × 832（155 KB）	Jmencisom	User created page with UploadWizard

文件用途

以下2个页面使用本文件：

全域文件用途

以下其他wiki使用此文件：

cs.wikipedia.org上的用途
- Žebřík kosmických vzdáleností
en.wikipedia.org上的用途
es.wikipedia.org上的用途
- Escalera de distancias cósmicas
et.wikipedia.org上的用途
- Mustand:Kosmiliste kauguse redel
eu.wikipedia.org上的用途
- Lankide:Joxan Garaialde/Distantzia kosmikoen eskailera
- Distantzia kosmikoen eskailera
fa.wikipedia.org上的用途
- نردبان فاصله کیهانی
fi.wikipedia.org上的用途
- Kosmiset etäisyystikapuut
mk.wikipedia.org上的用途
- Скала на вселенски растојанија
ms.wikipedia.org上的用途
- Paralaks
- Paralaks dalam astronomi

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提供者	NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU)
来源	ESA/Hubble
简短标题	Cosmic distance ladder
图像标题	For the calibration of relatively short distances the team observed Cepheid variables. These are pulsating stars which fade and brighten at rates that are proportional to their true brightness and this property allows astronomers to determine their distances. The researchers calibrated the distances to the Cepheids using a basic geometrical technique called parallax. With Hubble’s sharp-eyed Wide Field Camera 3 (WFC3), they extended the parallax measurements further than previously possible, across the Milky Way galaxy. To get accurate distances to nearby galaxies, the team then looked for galaxies containing both Cepheids and Type Ia supernovae. Type Ia supernovae always have the same intrinsic brightness and are also bright enough to be seen at relatively large distances. By comparing the observed brightness of both types of stars in those nearby galaxies, the team could then accurately measure the true brightness of the supernova. Using this calibrated rung on the distance ladder the accurate distance to additional 300 type Ia supernovae in far-flung galaxies was calculated. They compare those distance measurements with how the light from the supernovae is stretched to longer wavelengths by the expansion of space. Finally, they use these two values to calculate how fast the universe expands with time, called the Hubble constant.
使用条款	Creative Commons Attribution 4.0 International License
数据生成日期时间	2016年6月2日 (四) 17:30
联系信息	-{R\|http://www.spacetelescope.org}- Karl-Schwarzschild-Strasse 2 Garching bei M√ºnchen, , D-85748 Germany
IIM版本	4

File:Cosmic distance ladder.jpg

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