A selection of the latest astronomical news and discoveries.
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.
Curiosity Rover Confirms Ancient Lakes On Mars (03.11.15)
A new study from the team behind NASA’s Mars Science Laboratory/Curiosity has confirmed that Mars was once, billions of years ago, capable of storing water in lakes over an extended period of time.
Using data from the Curiosity rover, the team has determined that, long ago, water helped deposit sediment into Gale Crater, where the rover landed more than three years ago. The sediment deposited as layers that formed the foundation for Mount Sharp, the mountain found in the middle of the crater today.
“Observations from the rover suggest that a series of long-lived streams and lakes existed at some point between about 3.8 to 3.3 billion years ago, delivering sediment that slowly built up the lower layers of Mount Sharp,” said Ashwin Vasavada, Mars Science Laboratory project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and co-author of the new Science article which was published last month.
The findings build upon previous work that suggested that there were ancient lakes on Mars, and add to the unfolding story of a wet Mars, both past and present. In September, NASA scientists confirmed current water flows on Mars.
A view from the “Kimberley” formation on Mars taken by NASA’s Curiosity rover. The strata in the foreground dip towards the base of Mount Sharp, indicating flow of water toward a basin that existed before the larger bulk of the mountain formed.
NASA’s Cassini Spacecraft Encounters Enceladus For The Penultimate Time (02.11.15)
NASA’s Saturn orbiter probe, Cassini, made it’s penultimate flyby of the Saturnian moon Enceladus on 28th October 2015, flying just 30 miles above the icy moon’s surface at closest approach. The aim of the encounter was to fly through one of the icy water plumes coming from the south pole, something which has not been attempted previously, measuring it’s composition. The south polar plume reaches thousands of miles above the surface of Enceladus and Cassini found that it contains a combination of water and organics pulled from a sub-surface ocean, which scientists now believe is a global ocean around 10 to 15 miles beneath the moon’s icy crust. Cassini’s final flyby of Enceladus will take place in December 2015.
Two unprocessed images of Enceladus taken by Cassini during it’s 28th October fly-by. Left a wide field view of the moon and right the icy plumes studied by the craft.