Astronaut graffiti, muddy Mars and 'cloud streets'
From Earth to Mars, all the way to the site of the celebrated gravitational waves, Cosmos magazine art director Robyn Adderly presents her top five images from the week.
Footprints of a Martian flood
Water has left its mark in a variety of ways in this Martian scene, above, captured by the High Resolution Stereo Camera on the European Space Agency’s Mars Express.
The Arda Valles region of Mars, comprising the network of drainage valleys seen in the bottom portion of the image, lies on the western rim of an ancient large impact basin – seen in the top of the image.
The region has been heavily influenced by the action of water. In addition to drainage valleys, the crater to the right of centre was once filled by muddy sediments that later collapsed into the chaotic terrain seen in the crater floor. Zooming in below this crater, just above the bottom central crater, reveals light-toned deposits that have been identified as clays, formed in the presence of water.
The fractured terrain to the top of the scene is also linked to the loss of underground ice and evaporating water. They were likely formed as sediments deposited by water compacted.
Whence the gravitational waves came
The approximate location of the source of gravitational waves that were detected on 14 September 2015 by the twin Laser Interferometer Gravitational-wave Observatory (LIGO) facilities is shown on this sky map of the southern hemisphere.
The coloured lines represent different probabilities for where the signal originated: the purple line defines the region where the signal is predicted to have come from with a 90% confidence level; the inner yellow line defines the target region at a 10% confidence level.
The gravitational waves were produced by a pair of merging black holes located 1.3 billion light-years away.
A small galaxy near our own, called the Large Magellanic Cloud, can be seen as a fuzzy blob underneath the marked area, while an even smaller galaxy, called the Small Magellanic Cloud, is below it.
Researchers were able to home in on the location of the gravitational wave-source using data from the LIGO observatories in Livingston, Louisiana, and Hanford, Washington.
The gravitational waves arrived at Livingston seven milliseconds before arriving at Hanford. This time delay revealed a particular slice of sky, or ring, from which the signal must have arisen. Further analysis of the varying signal strength at both detectors ruled out portions of the ring, leaving the remaining patch shown on this map.
In the future, when additional gravitational wave detectors are up and running, scientists will be able to pinpoint more precisely the locations and sources of signals.
Building the world’s largest radio telescope
China is on track to complete construction of the world's largest and most sensitive radio telescope. The 500-metre Aperture Spherical Telescope, or FAST, will dwarf Puerto Rico's Arecibo Observatory, currently the largest radio telescope on the planet.
FAST located in a natural basin, in Pingtang County, Guizhou Province, southwest China. It began construction in 2011 and is scheduled for completion by September 2016.
It will have 4,600 triangular panels utilising a natural hollow to provide support for the telescope dish. As the name suggests, it will have a diameter of 500 metres and use an active surface that continually adjusts to create a parabola aligned with the desired sky direction.
There is a human cost to the massive project, though. The Xinhua news agency announced this week that more than 9,000 residents will be “evacuated” from their homes within a five-kilometre radius of the project to enforce a “quiet zone”, allowing detection of weak radio signals from space without Earthly interference.
Astronaut graffiti found in Apollo 11 command module
While 3-D scanning the Apollo 11 Command Module Columbia, staff at the Smithsonian's National Air and Space Museum has uncovered writing on the interior walls.
Unseen for almost 50 years, the markings include notes, figures and a calendar presumably written by the Apollo 11 astronauts during their historic flight to the moon. These markings give a glimpse into the first mission to land on the Moon, crewed by Neil Armstrong, Buzz Aldrin and Michael Collins.
The main control panel of the spacecraft pictured contains essential switches and indicators that had to be referred to and operated during the most crucial aspects of the flight. Numbers and references written by hand onto the panel can be checked against the audio and written transcripts from the mission to provide a more vivid picture of just what transpired.
The museum has been working with the Smithsonian’s digitisation program to scan the command module in 3-D to create a high-resolution interactive model of the entire spacecraft. This highly detailed model will allow researchers and the public to explore the entire craft, a feat not possible when viewing the artifact in the museum.
The model will be available in June on 3d.si.edu and used to produce an interactive display in the museum’s exhibition “Destination Moon”, scheduled to open in 2020.
Cloud streets and sea ice in the Sea of Okhotsk
The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Aqua satellite captured this image of cloud streets and sea ice in the Sea of Okhotsk.
Cloud streets are long parallel bands of cumulus clouds that form when cold air blows over warmer waters and a warmer air layer rests over the top of both.