Hubble view of a cosmological measuring tape

Hubble view of a cosmological measuring tape
Credit: NASA & ESA

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 , 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 , 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.


Explore further

Hubble view of a special spiral galaxy

Provided by NASA
Citation: Hubble view of a cosmological measuring tape (2015, April 10) retrieved 18 September 2019 from https://phys.org/news/2015-04-hubble-view-cosmological-tape.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
81 shares

Feedback to editors

User comments

Apr 11, 2015
"in the constellation of Leo Minor (The Little Lion)"

I think everyone either a) knows that, or b) doesn't care. Seriously, what possible use is translating the name of the constellation into English for someone that doesn't know that much about astronomy??? Have any of the "b" category even *heard* of "The Little Lion"? Really don't see what possible use the phrase could serve.

And besides, if you don't know Latin, you're too uneducated and ignorant to be reading this! Oh, for the old days, as recent as the 1960s, when every Ph.D knew Latin, Greek, English and one or two foreign languages...as a requirement for their degree. Now it's a business, and Americans are very proud of their anti-intellectualism.

Apr 11, 2015
@AGreatWhoper
As you have many ignorant comments you are the last one to be accusing anyone of being uneducated.

Apr 14, 2015
Sub: Urgent need - Cosmological index
Cosmology Definition- cosmic Function of the Universe- Cosmological Index through origins- Space Cosmology Vedas Interlinks- should help remove the cob-webs .
Why not create Centres of Excellence - promote East West interaction ?
Help Science to see Nature and Philosophy with objectivity.
SPACE VISION-OM-COSMOLOGICAL INDEX-By Vidyardhi Nanduri-TXU 1-731-970 - SPACE SCIENCE-Reports Cover [ESA]-2010- PROPOSALS-Environment-Sensex-Earth-Glow-Sun Life-Significance - Human Being in-depth-Milky-way Sensex-Aditya links
1.ENVIRONMENT SENSEX-EARTH'S GLOW-SUN-LIFE SIGNIFICANCE -.PPT-27
2.SUN TO ADITYA-COSMOLOGY VEDAS INTERLINKS –..PPT-27
3.COSMOLOGICAL INDEX-MILKYWAY SENSEX-VISIBLE -INVISIBLE MATRIX 2010..PPT-33

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more