The galaxy NGC 691 in the constellation Aries presents a stunning target for the Hubble Space Telescope, showing off near perfect spiral arms wrapped tightly around a brilliant core. Discovered by William Herschel in November 1786, NGC 691 is about 120 million light years from the Milky Way and measures some 130,000 light years across. A type 1a supernova, a class used as “standard candles” in surveys supporting the discovery of dark energy, was detected in NGC 691 in 2005.
New Hubble observations suggest that an immense cloud of hydrogen gas was launched from the outer regions of the galactic disc around 70 million years ago and is plummeting back toward our galaxy at nearly 700,000 miles per hour. If this so-called “Smith Cloud” could be seen in visible light, it would span the sky with an apparent diameter 30 times greater than the size of the full Moon.
The drizzle of stars scattered across this image forms an irregular dwarf galaxy known as UGC 4879. Some 2.3 million light-years from its closest neighbour, UGC 4879’s isolation means that it has not interacted with any surrounding galaxies, making it an ideal laboratory for astronomers looking to understand the complex mysteries of starbirth throughout the universe.
By pushing the NASA/ESA Hubble Space Telescope to its limits, astronomers have shattered the cosmic distance record by measuring the distance to the most remote galaxy ever seen in the universe. The galaxy, named GN-z11, has a redshift of 11.1, which corresponds to 400 million years after the Big Bang when the universe was only three percent of its current age.