Super sound system, hen in the heavens and Pluto’s twilight zone
It might take a bit of imagination, but can you make out a chicken in our weekly collection of favourite images? If not, don’t worry – Cosmos art director Robyn Adderly has four more for you to take in, including a look back at Pluto and a satellite map of the Netherlands’ shifting ground.
Secrets revealed from Pluto’s ‘Twilight Zone’
Sunlight filters through and illuminates Pluto’s complex atmospheric haze layers. NASA’s New Horizons spacecraft took this stunning image of Pluto only a few minutes after closest approach on 14 July 2015.
The southern portions of the nitrogen ice plains nicknamed Sputnik Planum, as well as mountains of the informally named Norgay Montes, can also be seen across Pluto’s crescent at the top of the image.
Looking back at Pluto with images such as this gives New Horizons scientists information about Pluto’s hazes and surface properties that they can’t get from images taken on approach.
Wall of sound
It looks like a giant sound system – and that is precisely what it is. The European Space Agency’s Large European Acoustic Facility (LEAF) chamber has one wall embedded with a set of enormous sound horns that can produce a range of noise up to more than 154 decibels, like standing close to multiple jets taking off.
It is used to subject satellites to the same noise a launcher produces as it takes off and flies through the atmosphere.
Steel-reinforced concrete walls coated with epoxy resin reflect noise in the chamber to produce a uniform sound field. As a safety feature, LEAF can operate only once all the doors are closed.
Mapping that sinking feeling
For a low-lying, densely populated country such as the Netherlands, monitoring subsidence is critical. Until recently, tiny displacements in the ground beneath our feet couldn’t be mapped nationally but now its possible thanks to the Sentinel-1 mission.
Scientists used radar images taken between November 2014 and April 2016 by the Sentinel-1A satellite to pinpoint where the ground is stable, where it is rising and where it is sinking – and, importantly, by exactly how much. Some 2.5 million measurements were used to compile the map above, which shows subsidence (red) and uplift (blue) in the northeast of the Netherlands. They found some areas are sinking by as much as 20 millimetres each year.
These measurements are, at the moment, accurate to a few millimetres. Within a couple of years this accuracy will improve further, approaching one millmetres per year over the entire country.
Running Chicken Nebula
To some, it looks like a giant chicken running across the sky. To others, it looks like a gaseous nebula where star formation takes place.
The nebula, also known as IC 2944, is a star-forming cloud in our Milky Way galaxy. It spans about 100 light-years and lies around 5,800 light-years from Earth toward the constellation of the Centaurus. Nicknamed the Running Chicken Nebula, from a bird-like shape some people see in its brightest region, it was captured recently in an 11-hour exposure from a backyard near Melbourne, Australia by Andrew Campbell.
Evolution painted onto butterfly and moth wings
A gene responsible for colours and colour patterns on the wings of butterflies and moths has been independently identified in two separate studies published this week in Nature. Scientists found a gene called cortex, and a mutation associated with it, controlled the darkening of the peppered moth that took place during the Industrial Revolution. The gene also dictates natural colour pattern variation in certain butterfly species, the studies find.