The subject of this Hubble image is NGC 5474, a dwarf galaxy located 21 million light-years away in the constellation of Ursa Major (The Great Bear). This beautiful image was taken with Hubble’s Advanced Camera for Surveys (ACS).
The term “dwarf galaxy” may sound diminutive, but don’t let that fool you — NGC 5474 contains several billion stars! However, when compared to the Milky Way with its hundreds of billions of stars, NGC 5474 does indeed seem relatively small.
NGC 5474 itself is part of the Messier 101 Group. The brightest galaxy within this group is the well-known spiral Pinwheel Galaxy (also known as Messier 101). This galaxy’s prominent, well-defined arms classify it as a “grand design galaxy,” along with other spirals Messier 81 and Messier 74.
Also within this group are Messier 101’s galactic neighbors. It is possible that gravitational interactions with these companion galaxies have had some influence on providing Messier 101 with its striking shape. Similar interactions with Messier 101 may have caused the distortions visible in NGC 5474.
Both the Messier 101 Group and our own Local Group reside within the Virgo Supercluster, making NGC 5474 something of a neighbor in galactic terms.
Astronomers using NASA’s Hubble Space Telescope have assembled a comprehensive picture of the evolving universe – among the most colorful deep space images ever captured by the 24-year-old telescope.
Researchers say the image, in new study called the Ultraviolet Coverage of the Hubble Ultra Deep Field, provides the missing link in star formation. The Hubble Ultra Deep Field 2014 image is a composite of separate exposures taken in 2003 to 2012 with Hubble’s Advanced Camera for Surveys and Wide Field Camera 3.
This fascinating space wallpaper shows the magnetic field of our Milky Way Galaxy as seen by ESA’s Planck satellite. This image was compiled from the first all-sky observations of polarized light emitted by interstellar dust in the Milky Way. The magnetic field is displayed using a visualization technique called line integral convolution (LIC).
This new Hubble image is centered on NGC 5793, a spiral galaxy over 150 million light-years away in the constellation of Libra. This galaxy has two particularly striking features: a beautiful dust lane and an intensely bright center — much brighter than that of our own galaxy, or indeed those of most spiral galaxies we observe.
NGC 5793 is a Seyfert galaxy. These galaxies have incredibly luminous centers that are thought to be caused by hungry supermassive black holes — black holes that can be billions of times the size of the sun — that pull in and devour gas and dust from their surroundings.
This galaxy is of great interest to astronomers for many reasons. For one, it appears to house objects known as masers. Whereas lasers emit visible light, masers emit microwave radiation. The term “masers” comes from the acronym Microwave Amplification by Stimulated Emission of Radiation. Maser emission is caused by particles that absorb energy from their surroundings and then re-emit this in the microwave part of the spectrum.
Naturally occurring masers, like those observed in NGC 5793, can tell us a lot about their environment; we see these kinds of masers in areas where stars are forming. In NGC 5793 there are also intense mega-masers, which are thousands of times more luminous than the sun.
Credit: NASA, ESA, and E. Perlman (Florida Institute of Technology)
In celebration of the 24th anniversary of the launch of NASA’s Hubble Space Telescope, astronomers have captured infrared-light images of a churning region of star birth 6,400 light-years away.
This colorful Hubble Space Telescope mosaic of a small portion of the Monkey Head Nebula unveils a collection of carved knots of gas and dust silhouetted against glowing gas. The cloud is sculpted by ultraviolet light eating into the cool hydrogen gas.
Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Apollo 8, the first manned mission to the moon, entered lunar orbit on Christmas Eve, Dec. 24, 1968. That evening, the astronauts-Commander Frank Borman, Command Module Pilot Jim Lovell, and Lunar Module Pilot William Anders-held a live broadcast from lunar orbit, in which they showed pictures of the Earth and moon as seen from their spacecraft. Said Lovell, “The vast loneliness is awe-inspiring and it makes you realize just what you have back there on Earth.” They ended the broadcast with the crew taking turns reading from the book of Genesis.
On Jan. 19, 2007, the Cassini spacecraft took this view of Saturn and its rings — the visible documentation of a technique called a “pi transfer” completed with a Titan flyby. A pi transfer uses the gravity of Saturn’s largest moon, Titan, to alter the orbit of the Cassini spacecraft so it can gain different perspectives on Saturn and achieve a wide variety of science objectives. During a pi transfer, Cassini flies by Titan at opposite sides of its orbit about Saturn (i.e., Titan’s orbital position differs by pi radians between the two flybys) and uses Titan’s gravity to change its orbital perspective on the ringed planet.
Taking in the rings in their entirety was the focus of this particular imaging sequence. Therefore, the camera exposure times were just right to capture the dark-side of its rings, but longer than that required to properly expose the globe of sunlit Saturn. Consequently, the sunlit half of the planet is overexposed.
The view is a mosaic of 36 images — that is, 12 separate sets of red, green and blue images — taken over the course of about 2.5 hours, as Cassini scanned across the entire main ring system. This view looks toward the unlit side of the rings from about 40 degrees above the ring plane.
The images in this natural-color view were obtained with the Cassini spacecraft wide-angle camera at a distance of approximately 1.23 million kilometers (764,000 miles) from Saturn. Image scale is 70 kilometers (44 miles) per pixel.