File:A cosmological measuring tape.jpg
页面内容不支持其他语言。
本预览的尺寸:663 × 600像素。 其他分辨率:265 × 240像素 | 531 × 480像素 | 849 × 768像素 | 1,132 × 1,024像素 | 1,280 × 1,158像素。
原始文件 (1,280 × 1,158像素,文件大小:247 KB,MIME类型:image/jpeg)
摘要
描述A cosmological measuring tape.jpg |
English: This NASA/ESA Hubble Space Telescope image shows the spiral galaxy NGC 3021 which lies about 100 million light-years away in the constellation of Leo Minor (The Little Lion). Among many other types of stars, this galaxy contains Cepheid variable stars, which can be used work out the distance to the galaxy. These stars pulsate at a rate that is closely related to their intrinsic brightness, so measurements of their rate of pulsation and their observed brightness give astronomers enough information to calculate the distance to the galaxy itself. Cepheids are also used to calibrate an even brighter distance marker, that can be used over greater distances: Type Ia supernovae. One of these bright exploding stars was observed in NGC 3021, back in 1995. In addition, the supernova in NGC 3021 was also used to refine the measurement of what is known as the Hubble constant. The value of this constant defines how fast the Universe is expanding and the more accurately we know it the more we can understand about the evolution of the Universe in the past as well as in the future. So, there is much more to this galaxy than just a pretty spiral. |
日期 | |
来源 | http://www.spacetelescope.org/images/potw1513a/ |
作者 | NASA & ESA / Acknowledgement: A. Riess (STScI) |
许可协议
ESA/Hubble images, videos and web texts are released by the ESA under the Creative Commons Attribution 4.0 International license and may on a non-exclusive basis be reproduced without fee provided they are clearly and visibly credited. Detailed conditions are below; see the ESA copyright statement for full information. For images created by NASA or on the hubblesite.org website, or for ESA/Hubble images on the esahubble.org site before 2009, use the {{PD-Hubble}} tag.
Conditions:
Notes:
|
此文件中描述的项目
描绘内容
30 3 2015
image/jpeg
253,294 字节
1,158 像素
1,280 像素
文件历史
点击某个日期/时间查看对应时刻的文件。
日期/时间 | 缩略图 | 大小 | 用户 | 备注 | |
---|---|---|---|---|---|
当前 | 2015年4月10日 (五) 15:25 | 1,280 × 1,158(247 KB) | Jmencisom | User created page with UploadWizard |
文件用途
全域文件用途
以下其他wiki使用此文件:
元数据
此文件含有额外信息,这些信息可能是创建或数字化该文件时使用的数码相机或扫描仪所添加的。如果文件已从其原始状态修改,某些详细信息可能无法完全反映修改后的文件。
图像标题 |
|
---|---|
提供者 | NASA & ESA Acknowledgement: A. Riess (STScI) |
来源 | ESA/Hubble |
简短标题 |
|
使用条款 |
|
数据生成日期时间 | 2015年3月30日 (一) 10:00 |
使用软件 | Adobe Photoshop CC 2014 (Windows) |
原始文件唯一ID | xmp.did:63d0ac98-6d1d-004b-96ec-44e49f886cfd |
关键词 | NGC 3021 |
联系信息 |
http://www.spacetelescope.org/ Karl-Schwarzschild-Strasse 2 Garching bei München, , D-85748 Germany |
IIM版本 | 4 |
隐藏分类: