Henrietta Leavitt Calibrates the Stars
27.10.1998

Humanity's understanding of the relative brightness and variability of stars was revolutionized by the work of Henrietta Swan Leavitt (1868-1921). Working at Harvard College Observatory, Leavitt precisely calibrated the photographic magnitudes of 47 stars to which all other stars could be compared.

Bright Stars, Dim Galaxy
3.11.2001

These two clusters of bright, newly formed stars surrounded by a glowing nebula lie 10 million light-years away in the dim, irregular galaxy cataloged as NGC 2366. The Hubble Space Telescope image shows that...

Bright Stars, Dim Galaxy
14.10.1996

These two clusters of bright, newly formed stars surrounded by a glowing nebula lie 10 million light years away in the dim, irregular galaxy cataloged as NGC 2366. The Hubble Space Telescope image shows...

T Tauri: A Star is Formed
3.08.2009

What does a star look like when it is forming? The prototypical example is the variable star T Tauri, visible as the bright orange star near the image center. The orange star centered in this remarkable telescopic skyview is T Tauri, prototype of the class of T Tauri variable stars.

V838 Mon: Light Echo Update
4.02.2005

Expanding light echoes continue to illuminate the dusty environs of V838 Monocerotis, mysterious variable star near the edge of our Galaxy. This stunning image, produced from Hubble data recorded in October of 2004, adds to a unique series of space-based, high-resolution views.

Stars of NGC 206
2.04.1999

Nestled within the dusty arms of the large spiral galaxy Andromeda (M31), the star cluster NGC 206 is one of the largest star forming regions known in our local group of galaxies. The beautiful...

The Swarm
28.01.2005

What do you call a group of black holes ... a flock, a brace, a swarm? Monitoring a region around the center of our Galaxy, astronomers have indeed found evidence for a surprisingly large number...

Cataclysmic Dawn
10.01.2015

Will this dawn bring another nova? Such dilemmas might be pondered one day by future humans living on a planet orbiting a cataclysmic variable binary star system. Cataclysmic variables involve gas falling from a large star onto an accretion disk surrounding a massive but compact white dwarf star.

Dawn Before Nova
17.11.2009

Will this dawn bring another nova? Such dilemmas might be pondered one day by future humans living on a planet orbiting a cataclysmic variable binary star system. Cataclysmic variables involve gas falling from a large star onto an accretion disk surrounding a massive but compact white dwarf star.

Edwin Hubble Discovers the Universe
6.10.2023

How big is our universe? This question, among others, was debated by two leading astronomers in 1920 in what has since become known as astronomy's Great Debate. Many astronomers then believed that our Milky Way Galaxy was the entire universe. Many others, though, believed that our galaxy was just one of many.