When the Hubble Space Telescope photographed the globular star cluster NGC 6752 (located 13,000 light-years away in our Milky Way’s halo), the image revealed a never-before-seen dwarf galaxy cataloged as Bedin 1 located far behind the cluster’s crowded stellar population. The galaxy is only 30 million light-years away but had not been noticed before. It’s classified as a dwarf spheroidal galaxy because it measures only around 3,000 light-years at its greatest extent. Because it’s so small, it’s roughly a thousand times dimmer than the Milky Way.
Because it’s very old, 13 billion years, and relatively isolated, it’s seen hardly any interaction with other galaxies It’s the astronomical equivalent of a living fossil from the early universe.
This composite image above shows the location of Bedin 1 behind the globular cluster NGC 6752. The lower image of the complete cluster is a ground-based observation from the Digitized Sky Survey 2. The upper right image shows the full field of view of the Hubble Space Telescope. The upper left image highlights the region containing the galaxy Bedin 1.
Image Credits: NASA / ESA / DSS / STScI
A long thread of hydrogen is being stripped from the spiral galaxy D100 as it drawn toward the center of the giant Coma galaxy cluster. This wide view is a composite of images taken by the Hubble Space Telescope and the Subaru Telescope in Hawaii. The narrow red streamer of hydrogen gas flowing from the galaxy’s center extends for nearly 200,000 light-years, but it is quite narrow–only 7,000 light-years wide. The tail’s clean edges and smooth structure suggests that it’s being held together by magnetic fields.
The Coma cluster is located 330 million light-years from Earth.
Image Credits: NASA / ESA / M. Sun (University of Alabama) / W. Cramer and J. Kenney (Yale University) / M. Yagi (National Astronomical Observatory of Japan)
This animation shows the different components that make up our home galaxy, the Milky Way. It starts at the black hole at the core of the Milky Way and the stars that orbit around it, before zooming out through the central Galactic Bulge, which hosts about ten billion stars. The zoom continues through a younger population of stars in the stellar disc, the home to most of the Milky Way’s stars. The discs and bulge are embedded in the stellar halo, a spherical structure that consists of a large number of globular clusters. These are the oldest stars in the Galaxy. An even larger halo of invisible dark matter is believed to surround the Milky Way. Its gravitational effect is evident in the motions of stars in the Galaxy.
Finally, this ESA-porduced video shows the extent of the stellar survey conducted by ESA’s Hipparcos mission, which surveyed more than 100,000 stars as far as 300 light-years from the Sun. ESA’s Gaia survey is in the process of cataloging a billion stars up to 30,000 light-years away.
If you’re going hitchhiking, remember to take your towel.
Video Credit: ESA
ESA’s Mars Express has been in orbit around Mars since Christmas Day, 2003.
Video Credit: ESA
Video Credit: NASA / ESA / ESO
This animation flies through the local galactic neighborhood to the Triangulum galaxy (M33), a smaller spiral than our Milky Way galaxy. It first zooms in on one of M33’s bright regions of star birth, the nebula cataloged as NGC 604, a glowing cloud of hot ionized hydrogen gas..
Video Credit: NASA / ESA / STScI