Skip to content
Vatican Observatory
  • About
    • Overview
    • Team
    • FAQ
  • Telescopes
    • Overview
    • Telescope Images
  • Tours
    • Castel Gandolfo
    • U.S.
  • Latest
    • Overview
    • Resources
    • Press
    • Audio
    • Video
    • Research
    • Authors
      • FAQs
    • Newsletter
    • Tucson Meteor Cameras
  • Podcast
  • Education
    • Overview
    • Resource Center
    • Image Gallery
    • Summer School
    • Books
    • Software
    • Additional Resources
    • ACME
  • Shop
  • Calendar
    • View our Event Calendar
  • Donate
    • Donate Now
    • Smart Ways to Give
    • Sacred Space Astronomy
      • View Content
    • Bequests / Trusts
    • The Foundation
      • Newsletters
      • Annual Reports
  • Press
    • VO in the News
    • Press Kit
  • Specola Vaticana
  • Contact
    • Contact
  • About
    • Overview
    • Team
    • FAQ
  • Telescopes
    • Overview
    • Telescope Images
  • Tours
    • Castel Gandolfo
    • U.S.
  • Latest
    • Overview
    • Resources
    • Press
    • Audio
    • Video
    • Research
    • Authors
      • FAQs
    • Newsletter
    • Tucson Meteor Cameras
  • Podcast
  • Education
    • Overview
    • Resource Center
    • Image Gallery
    • Summer School
    • Books
    • Software
    • Additional Resources
    • ACME
  • Shop
  • Calendar
    • View our Event Calendar
  • Donate
    • Donate Now
    • Smart Ways to Give
    • Sacred Space Astronomy
      • View Content
    • Bequests / Trusts
    • The Foundation
      • Newsletters
      • Annual Reports
  • Press
    • VO in the News
    • Press Kit
  • Specola Vaticana
  • Contact
    • Contact

Pasting the Legends onto Our Maps of the Heavens (Part One)

By Dr. Brenda Frye  |  12 Sep 2016

Share:
  • Share on Facebook
  • Share on Twitter
  • Share on LinkedIn
  • Share via Email

At the turn of the 20th century, astronomers were struggling with the question of how far away the ‘island universes,’
or other galaxies, are from us here in the Milky Way. It took the work of astronomer Henrietta Leavitt at Harvard College Observatory to tell us.

Ms. Leavitt was tasked with discovering the set of stars that change their brightness with time, the so-called ‘variable stars.’ She discovered nearly 1800 variable stars and noticed that some of them dimmed and then brightened again with predictable regularity. She measured the length of time it took for each variable star to undergo a full cycle of dimming and then brightening up again in a book published in the year 1908. At the end of book she noted that the brighter variable stars had longer such measured periods.

In between suffering from various illnesses and an unfortunate loss of hearing, she returned to this finding to establish an important relation regarding the set of variable stars now called “Cepheids.” The discovery was that there is a tight correlation between the total intrinsic brightness of a Cepheid variable star and its period, in the sense that the longer the period, the brighter the Cepheid star.

She measured the periods of Cepheids in one of the closest galaxies to us, the Large Magellanic Cloud. Based on the periods, she used her own relation of to determine what the luminosity is, which in turn is dependent on its distance from us by the inverse square law for light.

Voila! The distance to the Large Magellanic Cloud was found to be about 160,000 light years across, not far off from that of the diameter of the Milky Way. This discovery enabled astronomers to measure the distances to other nearby galaxies too. In Part Two we will look more at the work of this extraordinary person.

Share:
  • Share on Facebook
  • Share on Twitter
  • Share on LinkedIn
  • Share via Email

Sacred Space Astronomy

The Vatican Observatory’s official digital community and online magazine.

Become a Member

Recent Posts

How to Pray with the Stars with Br. Guy Consolmagno, SJ – AMDG Podcast

By Robert Trembley  |  7 May 2025  |  Sacred Space Astronomy

Vatican astronomer visits Mount St Mary’s College

Independent Catholic News  |  7 May 2025  |  Press

From the Vatican Observatory Faith and Science Pages — What God “Whispers” through Radio Telescopes

By Faith and Science  |  7 May 2025  |  Sacred Space Astronomy

Science and Painful Truth

By Mr. Christopher Graney  |  3 May 2025  |  Sacred Space Astronomy

Archives

      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • October
      • September
      • August
      • July
      • June
      • May
      • April
      • March
      • February
      • January
      • December
      • November
      • August
      • June
      • March
      • January
      • November
      • October
      • December
      • November
      • April
      • May
      • January
      • December
      • September
      • May
      • March
      • December
      • November
      • February

More Posts by
Dr. Brenda Frye

A Gift to Us?

By Dr. Brenda Frye  |  22 Aug 2020

Getting to Know a Neutron Star: How Heavy Can They Be?

By Dr. Brenda Frye  |  9 Jul 2020

The Flying Cell Phone to Alpha Centauri: Part Two

By Dr. Brenda Frye  |  21 Jun 2020

The Flying Cell Phone to Alpha Centauri: Part One

By Dr. Brenda Frye  |  28 May 2020

No Wine Before Its Time

By Dr. Brenda Frye  |  3 Jul 2018

Counting Exercise

By Dr. Brenda Frye  |  26 Jun 2018

View More

Newsletter

Upcoming astronomical events, scientific breakthroughs, philosophical reflections… just a few reasons to subscribe to our newsletter!

Vatican Observatory
  • About
  • Telescopes
  • Tours
  • Latest
  • Podcast
  • Education
  • Shop
  • Calendar
  • Donate
  • Press
  • Specola Vaticana
  • Contact
Privacy Policy  |   Cookie Policy  |   Disclosure Statement  |   This website is supported by the Vatican Observatory Foundation

Podcast:

  • Apple Podcasts Listen onApple Podcasts
  • Spotify Listen onSpotify
  • Google Podcasts Listen onGoogle Podcasts
  • Stitcher Listen onStitcher
  • Amazon Alexa Listen onAmazon Alexa
  • TuneIn Listen onTuneIn
Made by Longbeard