Discovered in 1784 by William Herschel, NGC 4394 is the archetypal barred spiral galaxy, with bright spiral arms emerging from the ends of a bar that cuts through the galaxy’s central bulge. Some 55 million light-years from Earth, the galaxy lies in the constellation of Coma Berenices. NGC 4394 is considered to be a member of the Virgo Cluster.
On Monday, 9 May there will be a rare transit of Mercury, when the innermost planet in our solar system will pass directly between the Earth and the Sun. The last time this happened was in 2006. With a properly filtered telescope and fine weather, the entire 7½-hour event can be seen from the British Isles.
Astronomers have found a unique object that appears to be made of material from the time of Earth’s formation, which has been preserved in the Oort Cloud for billions of years. C/2014 S3 (PANSTARRS) is the first object to be discovered on a long-period cometary orbit that has the characteristics of a pristine inner solar system asteroid.
Most of the cosmic rays arriving at Earth from our galaxy come from nearby clusters of massive stars, according to new observations from NASA’s Advanced Composition Explorer (ACE) spacecraft. But the detection of a few radioactive cosmic-ray iron nuclei also indicates that there has been a supernova in our galactic neighbourhood within the last few million years.
Craters with bright material on dwarf planet Ceres shine in new images from NASA’s Dawn mission taken from its lowest-altitude mapping orbit. Young crater Haulani (diameter 21 miles) and 6-mile-wide Oxo Crater — the second-brightest feature on Ceres — provide scientists with insight into the dwarf planet’s materials and surface morphology.
On 14 September 2015, gravitational waves produced by a pair of merging black holes gently rattled space-time in the vicinity of Earth. Less than half a second later, NASA’s Fermi Gamma-ray Space Telescope picked up a brief, weak burst of high-energy light consistent with the same part of the sky. Analysis of this burst suggests that the events are connected.
Scientists have determined that comets produce X-ray emission when particles in the solar wind strike the comet’s atmosphere. Recently, astronomers announced the results of a study using data collected with NASA’s Chandra X-ray Observatory of two comets — C/2012 S1 ISON and C/2011 S4 PanSTARRS — when both were relatively close to Earth.
The elegant simplicity of NGC 4111, seen here in this image from the NASA/ESA Hubble Space Telescope, hides a more violent history than you might think. NGC 4111 is a lenticular, or lens-shaped, galaxy, lying about 50 million light-years from us in the constellation of Canes Venatici (The Hunting Dogs).
Scientists on NASA’s New Horizons mission team are learning more about the structure and behaviour of Pluto’s complex atmosphere by discovering new attributes of its extensive haze layers. The hazes were first discovered by New Horizons in July 2015, as the spacecraft swept past Pluto and made its historic first exploration of the mysterious dwarf planet.
NASA’s Kepler planet-hunter spacecraft remains stable as the process of returning it to science continues. The cause of the anomaly, first reported on 8 April, remains under investigation. Charlie Sobeck, Kepler and K2 mission manager at NASA’s Ames Research Center, explains the steps taken by mission operations engineers to resume the K2 mission.
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