A sampling of recent articles, videos, and images from space-related science news items (find previous roundups here):

Astronomy

** A better view of an interstellar comet 2I/Borisov: Hubble Observes New Interstellar Visitor | ESA/Hubble

On 12 October 2019, the NASA/ESA Hubble Space Telescope provided astronomers with their best look yet at an interstellar visitor — Comet 2I/Borisov — which is believed to have arrived here from another planetary system elsewhere in our galaxy.

This observation is the sharpest  view ever of the interstellar comet. Hubble reveals a central concentration of dust around the solid icy nucleus.

Comet 2I/Borisov is only the second such interstellar object known to have passed through our Solar System. In 2017, the first identified interstellar visitor, an object dubbed ‘Oumuamua, swung within 38 million kilometres of the Sun before racing out of the Solar System. 

“Whereas ‘Oumuamua looked like a bare rock, Borisov is really active, more like a normal comet. It’s a puzzle why these two are so different,” explained David Jewitt of UCLA, leader of the Hubble team who observed the comet. 

** The Space Show – Tue, 10/15/2019 –  Dr. Alan Hale discussed “multiple astronomy, telescope and exoplanet subjects. Also Hale-Bopp and other comets. Alan’s new Ice and Stone 2020 educational outreach project.”

** The Milky Way steals gasses from unidentified neighbors:  Milky Way Raids Intergalactic ‘Bank Accounts,’ Hubble Study Finds | NASA

Our Milky Way is a frugal galaxy. Supernovas and violent stellar winds blow gas out of the galactic disk, but that gas falls back onto the galaxy to form new generations of stars. In an ambitious effort to conduct a full accounting of this recycling process, astronomers were surprised to find a surplus of incoming gas.

“We expected to find the Milky Way’s books balanced, with an equilibrium of gas inflow and outflow, but 10 years of Hubble ultraviolet data has shown there is more coming in than going out,” said astronomer Andrew Fox of the Space Telescope Science Institute, Baltimore, Maryland, lead author of the study to be published in The Astrophysical Journal.

Fox said that, for now, the source of the excess inflowing gas remains a mystery.

The Moon

** Both young and old craters at lunar south pole have water:

• Study suggests ice on lunar south pole may have more than one source | Brown University
• New Research Sheds Light on the Ages of Lunar Ice Deposits | NASA

The majority of the reported ice deposits are found within large craters formed about 3.1 billion years or longer ago, the study found. Since the ice can’t be any older than the crater, that puts an upper bound on the age of the ice. Just because the crater is old doesn’t mean that the ice within it is also that old too, the researchers say, but in this case there’s reason to believe the ice is indeed old. The deposits have a patchy distribution across crater floors, which suggests that the ice has been battered by micrometeorite impacts and other debris over a long period of time.

If those reported ice deposits are indeed ancient, that could have significant implications in terms of exploration and potential resource utilization, the researchers say.

“There have been models of bombardment through time showing that ice starts to concentrate with depth,” Deutsch said. “So if you have a surface layer that’s old, you’d expect more underneath.”

While the majority of ice was in the ancient craters, the researchers also found evidence for ice in smaller craters that, judging by their sharp, well-defined features, appear to be quite fresh. That suggests that some of the deposits on the south pole got there relatively recently.

“That was a surprise,” Deutsch said. “There hadn’t really been any observations of ice in younger cold traps before.”

** Chandrayaan-2 lunar orbiter begins producing science data: India’s Chandrayaan-2 Moon Probe Just Beamed Back Its 1st Lunar Science | Space.com

The Chandrayaan-2 mission launched in July and was designed to tackle a host of questions about the moon, with a particularly sharp eye to the water ice the spacecraft’s predecessor spotted at the south pole. The current orbiter carries eight different instruments — and Indian scientists are already poring over some of the mission’s very first science data.

The orbiter carries two cameras, both of which have been hard at work. The Terrain Mapping Camera began surveying the moon as soon as Chandrayaan-2 arrived in orbit. Now, the Indian Space Research Organisation (ISRO), which runs the mission, has also released images taken by a second instrument, the Orbiter High Resolution Camera.

More on Chandrayaan-2 at

• Chandrayaan2  – ISRO
• Chandrayaan-2 | The Planetary Society
• Solar flare observed by the Solar X-ray Monitor on Chandrayaan-2 – ISRO
• Chandrayaan2 – Images from the Orbiter High Resolution Camera – ISRO

The Sun

** The latest on the lack of sunspots: Sunspot update Sept 2019:The blankest Sun in decades – Behind The Black. The latest from Bob Zimmerman on the spotless sun:

With the release yesterday by NOAA of its September update of its graph showing the long term sunspot activity of the Sun, we find ourselves in what might be the longest stretch of sunspot inactivity in decades, part of what might become the most inactive solar minimum in centuries.

In the last four months the Sun has produced practically no sunspots. There were two in June, two in July, and one in August. The September graph, posted below with additional annotations by me to give it context, shows that the past month was as weak as August, with only one sunspot again.

Mars

** More signs of abundant ice on Mars: Ice! Ice! Everywhere on Mars ice! | Behind The Black.  Bob Zimmerman reports on further examples of “exposed ice in a number scarp cliff faces found in the high-mid-latitudes of Mars.

These scarps have so far been found in the highest latitudes of those two glacial bands, which might also explain why they appear more solid with the appearance of only the beginning of degradation. The buried glaciers found in the lower latitudes always look more degraded. As Dundas notes,

We expect that ice at lower latitudes will be less stable because the temperatures are warmer, so on average (over millions of years) at lower latitudes there will be less frequent deposition and more sublimation, so this fits together.

One striking conclusion that we can begin to draw from all this recent research is that ice is likely far more prevalent close to the Martian surface then previously believed. Not only will it be reachable by colonists by simply drilling down to an underground ice table, from 30 degrees latitude and higher there will be numerous places where it will be either close to the surface, or exposed and accessible.

** And more Mars surface imagery analysis from Bob Zimmerman at Behind The Black:

• A discontinuous Martian channel
• Sinkholes on Mars
• Skylights into Martian lava tube?
• Mars Express looks at Martian river relic
• The drying out of Mars

** Progress with the Insight lander’s Mole digger: Mars InSight’s ‘Mole’ Is Moving Again | NASA

NASA’s InSight spacecraft has used its robotic arm to help its heat probe, known as “the mole,” dig nearly 2 centimeters (3/4 of an inch) over the past week. While modest, the movement is significant: Designed to dig as much as 16 feet (5 meters) underground to gauge the heat escaping from the planet’s interior, the mole has only managed to partially bury itself since it started hammering in February 2019.

The recent movement is the result of a new strategy, arrived at after extensive testing on Earth, which found that unexpectedly strong soil is holding up the mole’s progress. The mole needs friction from surrounding soil in order to move: Without it, recoil from its self-hammering action will cause it to simply bounce in place. Pressing the scoop on InSight’s robotic arm against the mole, a new technique called “pinning,” appears to provide the probe with the friction it needs to continue digging.

Since Oct. 8, 2019, the mole has hammered 220 times over three separate occasions. Images sent down from the spacecraft’s cameras have shown the mole gradually progressing into the ground. It will take more time — and hammering — for the team to see how far the mole can go.

** Curiosity is staying busy:

— Curiosity Mars Rover: Wheel Scuff at Culbin Sands – Leonard David

NASA’s Curiosity Mars rover is now performing Sol 2558 tasks.

The rover has made a wheel scuff at “Culbin Sands,” reports Fred Calef, a planetary geologist at NASA’s Jet Propulsion Laboratory.

Curiosity purposely ran over a megaripple (fine grained sandy ripple with a coarser pebble coating), Calef notes, to create a “scuff” which churned up and bisected the feature to observe any layering or material within.

— Curiosity Mars Rover: Last Views of Drill Sample, Sand Dancing – Leonard David

Reports Ashley Stroupe, Mission Operations Engineer at NASA’s Jet Propulsion Laboratory, the rover is taking its last views of the Glen Etive 2 drill sample. A recent plan had the robot cleaning out the remaining sample within the drill and doing contact science analysis on the dumped sample.

Both the Chemistry and Camera (ChemCam) and Mastcam will be taking a look at “Penicuik,” a pebble target, and “Monach Isles,” a potential small meteorite. Also planned is a standard environmental observation suite: a Mastcam crater rim extinction and tau, and a Navcam supra-horizon movie.

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