A selection of the latest astronomical news and discoveries.
The Tiny Moon Phobos Is Photographed During Its Quick Trip Around Mars (09/08/17)
While photographing Mars, NASA’s Hubble Space Telescope captured a cameo appearance of the tiny moon Phobos on its trek around the Red Planet. Discovered in 1877, the diminutive, potato-shaped moon is so small that it appears star-like in the Hubble pictures. Phobos orbits Mars in just 7 hours and 39 minutes, which is faster than Mars rotates. The moon’s orbit is very slowly shrinking, meaning it will eventually shatter under Mars’ gravitational pull, or crash into the planet. Hubble took 13 separate exposures over 22 minutes to create a time-lapse video showing the moon’s orbital path.
Credit: NASA, ESA & STSci
Prometheus In Saturn’s F Ring (08/08/17)
The thin sliver of Saturn’s moon Prometheus lurks near ghostly structures in Saturn’s narrow F ring in this view from NASA’s Cassini spacecraft. Many of the narrow ring’s faint and wispy features result from its gravitational interactions with Prometheus (86 kilometers, or 53 miles across).
Most of the small moon’s surface is in darkness due to the viewing geometry here. Cassini was positioned behind Saturn and Prometheus with respect to the sun, looking toward the moon’s dark side and just a bit of the moon’s sunlit northern hemisphere.
Also visible here is a distinct difference in brightness between the outermost section of Saturn’s A ring (left of center) and rest of the ring, interior to the Keeler Gap (lower left).
This view looks toward the sunlit side of the rings from about 13 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 13, 2017.
The view was acquired at a distance of approximately 680,000 miles (1.1 million kilometers) from Saturn. Image scale is 4 miles (6 kilometers) per pixel.
The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.
Credit: NASA/JPL-Caltech/Space Science Institute
Saturn’s Shadow on Rings (19.05.17)
NASA’s Cassini spacecraft continues to provide spectacular images of Saturn and it’s rings as it continues it’s series of orbits between the cloud tops of Saturn and the rings.
The accompanying image was taken in February 2017 and was taken when the Cassini spacecraft was 1.2 million km from Saturn.
The next ring crossing by Cassini will take place in a couple of days time and will be the fifth out of the planned twenty two, before the spacecraft’s mission ends as it enters Saturn’s atmosphere on 15th September this year.
Charon’s Sub-Surface Ocean (25.02.16)
Pluto’s largest moon Charon may have once had an extensive sub-surface ocean according to the latest results released by the New Horizons mission.
Scientists believe that the findings could support the theory that the ocean, as it froze and expanded, cracked the outer crust of Charon and fractured it on a massive scale.
The side of Charon which was imaged as the New Horizons probe flew through the Pluto system in July 2015, is characterised by various tectonic faults. Scient…ists think that the sub-surface ocean was warmed by the decay of radioactive elements inside Charon, however as these elements decayed, the warming stopped and the ocean froze solid.
The below image shows a region of Charon informally named Serenity Chasma, part of a vast belt of chasms stretching around the equatorial region. The colour coded part, shows the topography of the area, at points over 4.5 miles deep.
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Mirror Assembly Completed For The James Webb Space Telescope (08.02.16)
Engineers at the Goddard Space Flight Centre, completed the installation of the final mirror segment of NASA’s James Webb Space Telescope at the start of February. The construction of the segmented mirror began last November and now fully assembled at 6.5 metres in diameter is considerably larger than the Hubble Space Telescopes mirror which is 2.4 metres across.
Unlike the Hubble Space Telescope, the James Webb Space Telescope will observe the universe at longer infra-red wavelengths where it will peer into the process of star and galaxy formation as well as analysing atmospheres of exo-planets.
Construction of the James Webb Space Telescope will continue over the coming months before extensive pre-launch testing commences. The telescope is due to be launched atop an Ariane 5 rocket from French Guiana in October 2018.
The constructed mirror of the James Webb Space Telescope. Credit: NASA
Highest Resolution Views Yet Of Pluto’s Surface (12.12.15)
Data continues to be received from the New Horizons spacecraft with the latest batch of images being returned containing some of the highest resolution images yet of Pluto’s surface, which were taken during the spacecraft’s closest approach.
The images show a wide variety of craters, mountains and glaciers. The latest images have resolutions of around 77 to 85 meters per pixel and are taken of a strip of Pluto’s surface around 80 kilometres wide in an area about 800 kilometres north west of the Sputnik Planum region.
These images were taken by the New Horizons Long Range Reconnaissance Imager (LORRI) in a timespan of around a minute about 15 minutes before the spacecraft’s closest approach to Pluto from a range of 17,000 kilometres.
Solar Activity Still High (01.12.15)
Although astronomers believe that the current solar maximum was reached in early 2014, activity levels continue to remain at reasonably high levels making solar observation still a worthwhile past-time, despite it’s low altitude in the UK’s winter sky.
NASA’s orbiting Solar Dynamics Observatory (SDO) observed spectacular magnetic looped plasma during the middle of November (below image) along with a number of coronal mass ejections which were observed in various different wavelengths.