What’s up in the May sky? A meteor shower produced by debris from Halley’s Comet, asteroids named after dinosaurs and a “blue moon” on May 18th. Additional information about topics covered in this episode of What’s Up, along with still images from the video and the video transcript are available at https://solarsystem.nasa.gov/…
… In perusing the April image release from the high resolution camera of Mars Reconnaissance Orbiter (MRO), I came across the image above, cropped and reduced to post here, of the discovery of another landslide within Hydraotes Chaos, one of the largest regions of chaos terrain on Mars. The image above was taken on February 9, 2019, and has since been followed up with a second image to create a stereo pair.
This is not the first landslide found in Hydraotes Chaos. I highlighted a similar slide on March 11. Both today’s landslide as well as the previous one likely represent examples of gravitational collapses as shown in this science paper about Martian ground water. Some scientists have proposed that Hydraotes Chaos was once an inland sea, and as the water drained away the loss of its buoyancy is thought to cause this kind of landslide at the base of cliffs and crater rims.
The past presence of water also helps explain the soft muddy look of this landslide. When this collapse occurred the material was likely saturated with water. Today it is most likely quite dry and hardened, but when it flowed it flowed like wet mud. Its size, almost a mile long and a quarter mile across, speaks to Mars’s low gravity, which would allow for large singular collapses like this.
** Ocean Worlds in the Outer Solar System is the title of a Silicon Valley Astronomy Lecture given recently by Kevin Hand of NASA JPL:
Dr. Kevin Hand of the Jet Propulsion Laboratory asks where the best place is to find life beyond Earth. He concludes it may be that the small, ice-covered moons of Jupiter and Saturn harbor some of the most habitable real estate in our Solar System. Life loves liquid water and these moons have lots of it! Dr. Hand explains the science behind our understanding of these worlds, with a special focus on Jupiter’s intriguing moon Europa, which is a top priority for future NASA missions.
NASA’s Mars InSight lander has measured and recorded for the first time ever a likely “marsquake.”
The faint seismic signal, detected by the lander’s Seismic Experiment for Interior Structure (SEIS) instrument, was recorded on April 6, the lander’s 128th Martian day, or sol. This is the first recorded trembling that appears to have come from inside the planet, as opposed to being caused by forces above the surface, such as wind. Scientists still are examining the data to determine the exact cause of the signal.
The seismometer signals can be converted to audio:
This video and audio illustrates a seismic event detected by NASA’s Mars InSight rover on April 6, 2019, the 128th Martian day, or sol, of the mission. Three distinct kinds of sounds can be heard, all of them detected as ground vibrations by the spacecraft’s seismometer, called the Seismic Experiment for Interior Structure (SEIS): noise from Martian wind, the seismic event itself, and the spacecraft’s robotic arm as it moves to take pictures. Credits: NASA/JPL-Caltech/CNES/IPGP/Imperial College London.
The new seismic event was too small to provide solid data on the Martian interior, which is one of InSight’s main objectives. The Martian surface is extremely quiet, allowing SEIS, InSight’s specially designed seismometer, to pick up faint rumbles. In contrast, Earth’s surface is quivering constantly from seismic noise created by oceans and weather. An event of this size in Southern California would be lost among dozens of tiny crackles that occur every day.
“The Martian Sol 128 event is exciting because its size and longer duration fit the profile of moonquakes detected on the lunar surface during the Apollo missions,” said Lori Glaze, Planetary Science Division director at NASA Headquarters.
Note that the signals’ frequencies “have been sped up by a factor of 60” since otherwise the vibrations would not be audible to the human ear.
** More quakes in the Cosmos are being detected more quickly with newly upgraded gravity wave observatories in the US and Italy. The sensitivities of the detectors have been increased to a level such that signals picked up at the LIGO (Laser Interferometer Gravitational-Wave Observatory) installations in Louisiana, and Washington plus the European Virgo detector in Italy will result in roughly one gravity wave detection per week. A new public alert system will let everyone know when a detection occurs:
Two new probable gravitational waves — ripples in the fabric of spacetime caused by cataclysmic cosmic events and first predicted by Albert Einstein over 100 years ago — have been detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo observatory in Italy in the first weeks after the detectors were updated. The source of both waves is believed to be the merging of a pair of black holes.
LIGO announced the discovery of the first new gravitational wave in its first-ever open public alert on April 8, and quickly followed up with a second announcement on April 12. LIGO detected the first-ever gravitational wave in September 2015, and announced the discovery in February 2016. Ten more gravitational waves were detected over the following three years, but with updates to LIGO and Virgo, scientists expect to see as many as one per week, which so far has proven true.
Updates to LIGO and Virgo have combined to increase its sensitivity by about 40 percent over its last run. Additionally, with this third observing run, LIGO and Virgo transitioned to a system whereby they alert the astronomy community almost immediately of a potential gravitational wave detection. This allows electromagnetic telescopes (X-ray, UV, optical, radio) to search for and hopefully find an electromagnetic signal from the same source, which can be key to understanding the dynamics of the event.
… The source of both gravitational waves is suspected to be compact binary mergers — the collision of two massive and incredibly dense cosmic objects into one another. Compact binary mergers can occur between two neutron stars, two black holes, or a neutron star and a black hole. Each of these different types of mergers create gravitational waves with strikingly different signals, so the LIGO team can identify the type of event that created the gravitational waves.
** Huge gallery of Rosetta mission images of comet 67P/Churyumov-Gerasimenko is now available on line at the OSIRIS Image Archive:
… was taken on 6 October 2014 from a distance of 18.6 km to the comet. This is just one of almost 70 000 images taken with Rosetta’s high-resolution imaging system OSIRIS that are now available via a new online and mobile-friendly ‘comet viewer’ created in a joint project with the Department of Information and Communication at Flensburg University of Applied Sciences, and the Max Planck Institute for Solar System Research, who lead the OSIRIS team.
The image viewer hosts the full archive, but also has subsections organising image sets into themes: for example, images showing towering cliffs and bizarre cracks on the comet surface, or those focusing on spectacular dust fountains as the comet launched gas and dust jets into space as its surface ices were warmed as it came closer to the Sun on its orbit.
The collection of OSIRIS images captured the farewell of lander Philae as it dropped towards the surface of the comet, and later, towards the end of the mission, the feverish search for the hidden robot.
Within the new comet viewer, each of the nearly 70 000 images is supplemented with the date on which it was taken, the distance to the comet, and a short accompanying text briefly describing what is seen in the image. The images can be downloaded in full resolution and can also be directly shared to Twitter and Facebook.
This incredible image of the hourglass-shaped Southern Crab Nebula was taken to mark the NASA/ESA Hubble Space Telescope’s 29th anniversary in space. The nebula, created by a binary star system, is one of the many objects that Hubble has demystified throughout its productive life. This new image adds to our understanding of the nebula and demonstrates the telescope’s continued capabilities.
On 24 April 1990, the NASA/ESA Hubble Space Telescope was launched on the space shuttle Discovery. It has since revolutionised how astronomers and the general public see the Universe. The images it provides are spectacular from both a scientific and a purely aesthetic point of view.
Each year the telescope dedicates a small portion of its precious observing time to take a special anniversary image, focused on capturing particularly beautiful and meaningful objects. This year’s image is the Southern Crab Nebula, and it is no exception [1].
This peculiar nebula, which exhibits nested hourglass-shaped structures, has been created by the interaction between a pair of stars at its centre. The unequal pair consists of a red giant and a white dwarf. The red giant is shedding its outer layers in the last phase of its life before it too lives out its final years as a white dwarf. Some of the red giant’s ejected material is attracted by the gravity of its companion.
How fast do things change on Mars? – A comparison of Mars Reconnaissance Orbiter images of a dune-like feature on Mars taken 12 years apart show some differences. “Overall, however, not much is different. Though dunes definitely change on Mars, they do so much more slowly than on Earth. And in some cases what look like dunes are not really dunes at all, but a form of cemented sandstone, exhibiting even fewer changes over long time spans.”
** Some space sciences webcasts:
>> Weekly Space Hangout: Apr 17, 2019 – Dr. Dorothy Oehler Talks “Is there Methane on Mars?”
>> SETI Institute: Tiny Neptune Moon Spotted by Hubble May Have Broken from Larger Moon
>> SETI Institute: Mars Exploration Rovers: Spirit and Opportunity with Nathalie Cabrol
>> SETI Institute: Turkish Meteorite Traced to Impact Crater on Asteroid Vesta
A recent episode of the TMRO.tv Space show: Why JWST’s first images will just be 18 fuzzy blobs
This week we are joined by NASA’s James Webb Space Telescope Program Scientist Dr. Eric Smith. We talk about the most ambitious space telescope project humans have ever undertaken, and why when we get the first images back it will likely just be 18 fuzzy blobs.
** And here is another: APL’s Interstellar Probe
The always energetic and information powerhouse Dr. Kirby Runyon joins us to talk about New Horizons, Yuris Night and announces the Johns Hopkins University Applied Physics Lab Interstellar Probe. It’s a really fun and exciting interview, and we had a bit of stuff we missed in After Dark so we left a bit of that in there at the end as well.
** A space news report: RocketLab announces Photon, ISS Spacewalks and the weight of the galaxy!
This week in Space News from TMRO we have: Rocket Lab announces their Photon satellite system US Spacewalk 53, Space Suit Mixup Milky Way Weight There were 2 Soyuz launches in Space Traffic and of course the Space Weather Woman Dr. Tamitha Skov brings is our Space Weather.