Category Archives: Solar Science

Space sciences roundup – Dec.5.2019

December 5, 2019 TopSpacer

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

Sun

** Initial results from Parker Solar Probe published: First NASA Parker Solar Probe Results Reveal Surprising Details of Sun – NASA

The information Parker has uncovered about how the Sun constantly ejects material and energy will help scientists rewrite the models they use to understand and predict the space weather around our planet, and understand the process by which stars are created and evolve. This information will be vital to protecting astronauts and technology in space – an important part of NASA’s Artemis program, which will send the first woman and the next man to the Moon by 2024 and, eventually, on to Mars.

The four papers, now available online from the journal Nature, describe Parker’s unprecedented near-Sun observations through two record-breaking close flybys. They reveal new insights into the processes that drive the solar wind – the constant outflow of hot, ionized gas that streams outward from the Sun and fills up the solar system – and how the solar wind couples with solar rotation. Through these flybys, the mission also has examined the dust of the coronal environment, and spotted particle acceleration events so small that they are undetectable from Earth, which is nearly 93 million miles from the Sun.

During its initial flybys, Parker studied the Sun from a distance of about 15 million miles. That is already closer to the Sun than Mercury, but the spacecraft will get even closer in the future, as it travels at more than 213,000 mph, faster than any previous spacecraft.

Solar scientists discuss the Parker findings:

Parker imagery shows outflow of particles from the Sun:

Video: The WISPR image on NASA’s Parker Solar Probe captured imagery of the constant outflow of material from the Sun during its close approach to the Sun in April 2019. Credits: NASA/NRL/APL

Astronomy

** Gravitational lensing by massive galaxy cluster multiples views of a galaxy behind it: Hubble Captures a Dozen Sunburst Arc Doppelgangers | ESA/Hubble

Astronomers using the NASA/ESA Hubble Space Telescope have observed a galaxy in the distant regions of the Universe which appears duplicated at least 12 times on the night sky. This unique sight, created by strong gravitational lensing, helps astronomers get a better understanding of the cosmic era known as the epoch of reionisation.

This new image from the NASA/ESA Hubble Space Telescope shows an astronomical object whose image is multiplied by the effect of strong gravitational lensing. The galaxy, nicknamed the Sunburst Arc, is almost 11 billion light-years away from Earth and has been lensed into multiple images by a massive cluster of galaxies 4.6 billion light-years away [1].

The mass of the galaxy cluster is large enough to bend and magnify the light from the more distant galaxy behind it. This process leads not only to a deformation of the light from the object, but also to a multiplication of the image of the lensed galaxy.

** Hubble telescope spots a face in a galactic collision: Hubble Captures Cosmic Face | ESA/Hubble

Although galaxy collisions are common — especially in the early universe — most are not head-on impacts like the collision that likely created this Arp-Madore system 704 million light-years from Earth. This violent encounter gives the system an arresting ring structure, but only for a short amount of time. The crash has pulled and stretched the galaxies’ discs of gas, dust, and stars outward, forming the ring of intense star formation that shapes the “nose” and “face” features of the system.

Ring galaxies are rare, and only a few hundred of them reside in our larger cosmic neighbourhood. The galaxies have to collide at just the right orientation so that they interact to create the ring, and before long they will have merged completely, hiding their messy past.

The side-by-side juxtaposition of the two central bulges of stars from the galaxies that we see here is also unusual. Since the bulges that form the “eyes” appear to be the same size, we can be sure that the two galaxies involved in the crash were of equal size. This is different from the more common collisions in which small galaxies are gobbled up by their larger neighbours.

This new image from the NASA/ESA Hubble Space Telescope captures two galaxies of equal size in a collision that appears to resemble a ghostly face. This observation was made on 19 June 2019 in visible light by the telescope’s Advanced Camera for Surveys. Residing 704 million light-years from Earth, this system is catalogued as Arp-Madore 2026-424 (AM 2026-424) in the Arp-Madore “Catalogue of Southern Peculiar Galaxies and Associations”.

** An interview with astronomer and astrophotographer Dylan O’Donnell of Australia:

Check out O’Donnell’s astrophotography gallery. And here is a talk he recently gave about imaging the Southern Sky:

Moon

** Citizen scientist spots crash site of India’s Vikram lander in images from the Lunar Reconnaissance Orbiter.

From NASA:

The Chandrayaan 2 Vikram lander was targeted for a highland smooth plain about 600 kilometers from the south pole; unfortunately the Indian Space Research Organisation (ISRO) lost contact with their lander shortly before the scheduled touchdown (Sept. 7 in India, Sept. 6 in the United States). Despite the loss, getting that close to the surface was an amazing achievement. The Lunar Reconnaissance Orbiter Camera team released the first mosaic (acquired Sept. 17) of the site on Sept. 26 and many people have downloaded the mosaic to search for signs of Vikram. Shanmuga Subramanian contacted the LRO project with a positive identification of debris.

After receiving this tip, the LROC team confirmed the identification by comparing before and after images. When the images for the first mosaic were acquired the impact point was poorly illuminated and thus not easily identifiable. Two subsequent image sequences were acquired on Oct. 14 and 15, and Nov. 11. The LROC team scoured the surrounding area in these new mosaics and found the impact site (70.8810°S, 22.7840°E, 834 m elevation) and associated debris field. The November mosaic had the best pixel scale (0.7 meter) and lighting conditions (72° incidence angle).

The debris first located by Shanmuga is about 750 meters northwest of the main crash site and was a single bright pixel identification in that first mosaic (1.3 meter pixels, 84° incidence angle). The November mosaic shows best the impact crater, ray and extensive debris field. The three largest pieces of debris are each about 2×2 pixels and cast a one pixel shadow.

“This before and after image ratio highlights changes to the surface; the impact point is near center of the image and stands out due the dark rays and bright outer halo. Note the dark streak and debris about 100 meters to the SSE of the impact point. Diagonal straight lines are uncorrected background artifacts. Credits: NASA/Goddard/Arizona State University”

** China’s Chang’e-4 lander module and Yutu-2 rover complete their 12th lunar day activities and are now shutting down for the 14 earth-day long lunar night.

China’s lunar rover Yutu-2 has driven 345.059 meters on the far side of the moon to conduct scientific exploration of the virgin territory.

…

Due to the complicated geological environment and the rugged and heavily cratered terrain on the far side of the moon, Chinese space engineers carefully planned the driving routes of the rover to ensure its safety.

Driving slowly but steadily, the Yutu-2 is expected to continue traveling on the moon and make more scientific discoveries, said CNSA.

** The FARSIDE project proposes to place a radio telescope array on the far side of the Moon:

FARSIDE (Farside Array for Radio Science Investigations of the Dark ages and Exoplanets) is a Probe-class concept to place a low radio frequency interferometric array on the farside of the Moon. A NASA-funded design study, focused on the instrument, a deployment rover, the lander and base station, delivered an architecture broadly consistent with the requirements for a Probe mission. This notional architecture consists of 128 dipole antennas deployed across a 10 km area by a rover, and tethered to a base station for central processing, power and data transmission to the Lunar Gateway, or an alternative relay satellite.

Asteroids & Comets

** Japan Hayabusa-2 probe returning with samples of the asteroid Ryugu. A capsule with the samples will reach the Australian Outback in late 2020.

” Asteroid Ryugu captured with the Optical Navigation Camera – Telescopic (ONC-T) immediately after departure. Image time is November 13 10:15 JST (onboard time), 2019.
Image credit ※: JAXA, Chiba Institute of Technology, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Meiji University, University of Aizu, AIST.”

** A discussion of the metal rich asteroid Psyche, which will be visited by a NASA probe to launch in 2020: The Prospects of Heavy Metal – Podcasts/NASA Jet Propulsion Laboratory

Asteroids, ho! Pioneering space miners dream of Psyche, the largest metal asteroid in the solar system.

** TESS space observatory watched a comet erupt as it passed in view: NASA’s Exoplanet-Hunting Mission Catches a Natural Comet Outburst – NASA

Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers at the University of Maryland (UMD), in College Park, Maryland, have captured a clear start-to-finish image sequence of an explosive emission of dust, ice and gases during the close approach of comet 46P/Wirtanen in late 2018. This is the most complete and detailed observation to date of the formation and dissipation of a naturally-occurring comet outburst. The team members reported their results in the November 22 issue of The Astrophysical Journal Letters.

“TESS spends nearly a month at a time imaging one portion of the sky. With no day or night breaks and no atmospheric interference, we have a very uniform, long-duration set of observations,” said Tony Farnham, a research scientist in the UMD Department of Astronomy and the lead author of the research paper. “As comets orbit the Sun, they can pass through TESS’ field of view. Wirtanen was a high priority for us because of its close approach in late 2018, so we decided to use its appearance in the TESS images as a test case to see what we could get out of it. We did so and were very surprised!”

“This animation shows an explosive outburst of dust, ice and gases from comet 46P/Wirtanen that occurred on September 26, 2018 and dissipated over the next 20 days. The images, from NASA’s TESS spacecraft, were taken every three hours during the first three days of the outburst. Credits: Farnham et al./NASA. View enlarged image“

Mars

** A big set of Mars images of interest have been examined Bob Zimmerman at Behind the Black:

Pits and caves:
Glaciers:
- Mid-latitude Martian glacier?
- Mars Express confirms ancient glaciers in northern Martian mid-latitudes
SpaceX landing site studies:
- SpaceX completes 1st round of Starship’s Mars landing site images
- Further explorations at candidate Starship Mars landing site
Interesting features:

** Updates on Curiosity:

“Curiosity Left B Navigation Camera image taken on Sol 2602, December 1, 2019. Credit: NASA/JPL-Caltech” – LeonardDavid.com

** Seasonal boost in the oxygen level detected by Curiosity is not understood: With Mars Methane Mystery Unsolved, Curiosity Serves Scientists a New One: Oxygen – NASA’s Mars Exploration Program

For the first time in the history of space exploration, scientists have measured the seasonal changes in the gases that fill the air directly above the surface of Gale Crater on Mars. As a result, they noticed something baffling: oxygen, the gas many Earth creatures use to breathe, behaves in a way that so far scientists cannot explain through any known chemical processes.

…

Within this environment, scientists found that nitrogen and argon follow a predictable seasonal pattern, waxing and waning in concentration in Gale Crater throughout the year relative to how much CO₂is in the air. They expected oxygen to do the same. But it didn’t. Instead, the amount of the gas in the air rose throughout spring and summer by as much as 30%, and then dropped back to levels predicted by known chemistry in fall. This pattern repeated each spring, though the amount of oxygen added to the atmosphere varied, implying that something was producing it and then taking it away.

“Seasonal Variations in Oxygen at Gale Crater: Graph showing oxygen concentration through Mars seasons. Image credit: Melissa Trainer/Dan Gallagher/NASA Goddard “

** A review of the discoveries of the Spirit and Opportunity rovers: A New Understanding | The Planetary Society

The findings from the Mars Exploration Rovers allowed the Mars science community to develop our strategy for Mars exploration beyond “follow the water” to the more complicated question of whether these watery environments were ever habitable. Very loosely defined, a habitable environment is one that has the 2 other essential requirements in addition to liquid water that are needed to support life as we know it: a source of carbon and a source of energy. The Mars Science Laboratory mission’s Curiosity rover, which landed on Mars in 2012, carried a larger and more complicated payload than the Mars Exploration Rovers. Curiosity is capable of finding evidence of all 3 of these requirements. In fact, it has succeeded: within its landing site at Gale crater, Curiosity found ancient river and lake deposits that preserved carbon-containing compounds as well as evidence for water chemistry that could power microbial metabolism. Today, we not only know that Mars was once wet—it was also habitable.

** China’s Mars plans:

China has performed a hover and hazard avoidance test on a model the country’s first Mars rover, while engineers ready the real spacecraft for launch toward the red planet in mid-2020.

Comprising an orbiter, lander and rover, the mission aims to become the first Chinese spacecraft to reach Mars after lifting off aboard a Long March 5 rocket — the country’s most powerful launcher — during a several week window opening in July 2020.

The mission will launch from the Wenchang space center on Hainan Island, China’s newest spaceport.

Jupiter

** Juno continues its orbital studies of Jupiter and continues to provide amazing images. For example, Jovian Vortex View – Mission Juno:

Juno captured this stunningly detailed look at a cyclonic storm in Jupiter’s atmosphere during its 23rd close flyby of the planet (also referred to as “perijove 23”).

Juno observed this vortex in a region of Jupiter called the “north north north north temperate belt,” or NNNNTB, one of the gas giant planet’s many persistent cloud bands. These bands are formed by the prevailing winds at different latitudes. The vortex seen here is roughly 1,200 miles (2,000 kilometers) wide.

Jupiter is composed mostly of hydrogen and helium, but some of the color in its clouds may come from plumes of sulfur and phosphorus-containing gases rising from the planet’s warmer interior.

Citizen scientist Kevin M. Gill created this image using data from the spacecraft’s JunoCam imager. It was taken on Nov. 3, 2019, at 2:08 p.m. PST (5:08 p.m. EST). At the time, the spacecraft was about 5,300 miles (8,500 kilometers) from Jupiter’s cloud tops above a latitude of about 49 degrees.

====

One Giant Leap:
The Impossible Mission That Flew Us to the Moon

Astronomy, Solar Science, Space Science

Space sciences roundup – Nov.6.2019

November 6, 2019 TopSpacer

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

Exoplanets

** TESS (Transiting Exoplanet Survey Satellite) has found 29 exoplanets so far in a survey of southern sky: NASA’s TESS Presents Panorama of Southern Sky | NASA

… Constructed from 208 TESS images taken during the mission’s first year of science operations, completed on July 18, the southern panorama reveals both the beauty of the cosmic landscape and the reach of TESS’s cameras.

“Analysis of TESS data focuses on individual stars and planets one at a time, but I wanted to step back and highlight everything at once, really emphasizing the spectacular view TESS gives us of the entire sky,” said Ethan Kruse, a NASA Postdoctoral Program Fellow who assembled the mosaic at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Within this scene, TESS has discovered 29 exoplanets, or worlds beyond our solar system, and more than 1,000 candidate planets astronomers are now investigating.

TESS divided the southern sky into 13 sectors and imaged each one of them for nearly a month using four cameras, which carry a total of 16 charge-coupled devices (CCDs). Remarkably, the TESS cameras capture a full sector of the sky every 30 minutes as part of its search for exoplanet transits. Transits occur when a planet passes in front of its host star from our perspective, briefly and regularly dimming its light. During the satellite’s first year of operations, each of its CCDs captured 15,347 30-minute science images. These images are just a part of more than 20 terabytes of southern sky data TESS has returned, comparable to streaming nearly 6,000 high-definition movies.

Solar system

** “Encounter with Ultima Thule: The Most Distant Object Humanity Has Ever Explored”

After encountering Pluto, the New Horizons spacecraft, for the first time flew by a member of the Kuiper Belt of icy objects beyond Neptune. This particular object, informally named “Ultimate Thule” (meaning the farthest place beyond the known world,) turned out to be a “contact binary” – two smaller icy worlds stuck together. Dr. Moore shares an insider’s view (with great images) of how the mission got there and what we learned at Ultima Thule.

Asteroids

** “ESO Telescope Reveals What Could be the Smallest Dwarf Planet Yet in the Solar System” | ESO

Astronomers using ESO’s SPHERE instrument at the Very Large Telescope (VLT) have revealed that the asteroid Hygiea could be classified as a dwarf planet. The object is the fourth largest in the asteroid belt after Ceres, Vesta and Pallas. For the first time, astronomers have observed Hygiea in sufficiently high resolution to study its surface and determine its shape and size. They found that Hygiea is spherical, potentially taking the crown from Ceres as the smallest dwarf planet in the Solar System.

As an object in the main asteroid belt, Hygiea satisfies right away three of the four requirements to be classified as a dwarf planet: it orbits around the Sun, it is not a moon and, unlike a planet, it has not cleared the neighbourhood around its orbit. The final requirement is that it has enough mass for its own gravity to pull it into a roughly spherical shape. This is what VLT observations have now revealed about Hygiea.

“A new SPHERE/VLT image of Hygiea, which could be the Solar System’s smallest dwarf planet yet. As an object in the main asteroid belt, Hygiea satisfies right away three of the four requirements to be classified as a dwarf planet: it orbits around the Sun, it is not a moon and, unlike a planet, it has not cleared the neighbourhood around its orbit. The final requirement is that it have enough mass that its own gravity pulls it into a roughly spherical shape. This is what VLT observations have now revealed about Hygiea.” – ESO

The making of a dwarf planet:

Computational simulation of the fragmentation and reassembly that led to the formation of Hygiea and its family of asteroids, following an impact with a large object. While changes in the shape of Hygiea occur after the impact, the dwarf-planet candidate eventually acquires a round shape.

** The story of Professor Amy Mainzer and the NEOCam space asteroid observatory: One scientist’s 15-year (and counting) quest to save Earth from asteroid impacts – The Space Review

NEOCam is a 50-centimeter telescope that will discover and characterize a large fraction of the asteroids and comets in the inner part of the solar system. It was supported based on its fundamental science, but the data that it will produce also serves planetary defense, which can be considered applied science. NASA administrator Jim Bridenstine has been called “passionate” about planetary defense and the American public agrees: in a recent AP-NORC poll of US priorities in space, monitoring asteroids was considered top priority by 68 percent of those polled, higher than any other category (59 percent prioritized scientific research and exploration; 23 percent and 27 percent prioritized human exploration of the Moon and Mars, respectively; and 19 percent prioritized a US military presence in space.) Imagine how much any presidential candidate would like to poll at 68 percent!

Sun

** The sun remains nearly spotless: Sunspot update October 2019: Sunspot activity continues to flatline | Behind The Black

Even though the previous 2008-2009 solar minimum was one of the deepest and longest ever recorded, the lack of sunspots in the past five months has significantly beaten it for inactivity, as shown on the first graph above. That previous minimum never had a period of even two months with so few sunspots. Furthermore, the Sun has now been blank 74% of the time in 2019, a record of blankness that beats the yearly record of either 2008 or 2009. If the Sun continues to be as blank as it has been for the next two months, 2019 will easily set the record for the year with the fewest sunspots ever recorded.

The big question remains: Are we heading for a grand minimum with no sunspots for decades? We still do not know. Even these unprecedented trends prove nothing, as we really do not yet have a clear understanding of why the Sun undergoes these various cycles of sunspot activity/inactivity. The Sun could still come back to life in the coming years. We can only wait and see.

Astronomy

** The captivating beauty of a galactic smashup: Hubble Captures Cosmic Face | ESA/Hubble

** Heavy element production seen at site of a neutron star collision that was spotted with gravitational wave detection: First identification of a heavy element born from neutron star collision | ESO

For the first time, a freshly made heavy element, strontium, has been detected in space, in the aftermath of a merger of two neutron stars. This finding was observed by ESO’s X-shooter spectrograph on the Very Large Telescope (VLT) and is published today in Nature. The detection confirms that the heavier elements in the Universe can form in neutron star mergers, providing a missing piece of the puzzle of chemical element formation.

In 2017, following the detection of gravitational waves passing the Earth, ESO pointed its telescopes in Chile, including the VLT, to the source: a neutron star merger named GW170817. Astronomers suspected that, if heavier elements did form in neutron star collisions, signatures of those elements could be detected in kilonovae, the explosive aftermaths of these mergers. This is what a team of European researchers has now done, using data from the X-shooter instrument on ESO’s VLT.

The Moon

** China’s lunar far-side exploration mission continues. Both the Yutu-2 rover and Chang’e-4 lander are demonstrating impressive resilience after multiple exposures to the deep cold of the 2 week long lunar nights. (Each uses a radioisotope heater unit to stay warm.) China’s lunar rover travels over 300 meters on moon’s far side – Xinhua

China’s lunar rover Yutu-2 has driven 318.62 meters on the far side of the moon to conduct scientific exploration of the virgin territory.

Both the lander and the rover of the Chang’e-4 probe have ended their work for the 11th lunar day, and switched to dormant mode for the lunar night on Monday (Beijing time), according to the Lunar Exploration and Space Program Center of the China National Space Administration.

The rover is now located 218.11 meters northwest of the lander.

…

The scientific tasks of the Chang’e-4 mission include conducting low-frequency radio astronomical observation, surveying the terrain and landforms, detecting the mineral composition and shallow lunar surface structure and measuring neutron radiation and neutral atoms.

** India’s Chandrayaan-2 orbiter starting to produce data from the 8 instruments aboard the spacecraft. The first findings include the detection of Argon-40 in the tenuous lunar atmosphere using a mass spectrometer and images with the Dual-Frequency Synthetic Aperture Radar (DF-SAR) that highlight the structures of image craters.

An initial image of the lunar surface from the Dual-Frequency Synthetic Aperture Radar (DF-SAR) on Chandrayaan-2. Credits: ISRO

More about the orbiter:

** The LROC imager on the Lunar Reconnaissance Orbiter captures dramatic views of the Bhabha crater, which lies within the South Pole–Aitken (SPA) basin on the Moon’s farside: Dawn Over Bhabha Crater | Lunar Reconnaissance Orbiter Camera

“Central peak complex of Bhabha crater (70 kilometer diameter) rising from the shadows of dawn, image snapped on 28 August 2019 from an altitude of 73 kiolmeters. View is seen from east-to-the west, north is to the right, visible portion of central peak complex is about 14 kilometers wide, NAC M1321101374LR [NASA/GSFC/Arizona State University].”

Suborbital space sciences

** Research on reusable suborbital rocket vehicles will be the focus of the 2020 Next-Generation Suborbital Researchers Conference (NSRC) in Broomfield, Colorado, March 2-4, 2020: Southwest Research Institute, Commercial Spaceflight Federation announce suborbital space researchers, educators conference – SwRI

The conference will provide an in-depth forum for attendees to learn more about funding and conducting research and public outreach aboard new commercial suborbital spaceflight systems — fortuitous byproducts of space tourism. Representatives from NASA, the Federal Aviation Administration, spaceports, and commercial suborbital and orbital vehicle operators will attend.

“A new era of routine access to suborbital space for researchers and educators is fast approaching,” said SwRI Associate Vice President Dr. Alan Stern, the NSRC program chair. “The 2020 conference will explore the many revolutionary ways this will affect space research and education.”

Organized by SwRI and the Commercial Spaceflight Federation (CSF), NSRC-2020 will feature dozens of keynote and invited presentations, panel discussions, workshops, aerospace tours, presentations, posters and networking opportunities.

“As a growing number of commercial space companies provide low-cost and frequent access to suborbital space for humans and research payloads, 2020 is the time to fully utilize this game-changing capability,” added Eric Stallmer, president of CSF. “NSRC-2020 will be the epicenter for researchers, educators, companies, students and entrepreneurs to connect and take part in this new era.”

NSRC is the premier conference for the suborbital space research and education community. The 2020 conference follows six previous, highly successful meetings since 2010. The program, sponsors, registration, logistics and other conference details are available at http://nsrc.swri.org.

Mars

** Insight‘s heat probe digger dug again and appeared to be doing well by getting traction from pressure put on its side by Insight’s robotic arm: Mole Digging on Mars: Breakthrough! – Leonard David – Oct.24.2019

“We have made important progress in our attempts to get the mole digging again…in fact, we got it digging again!”

That’s the word from Tilman Spohn of the German Aerospace Center’s (DLR) Institute of Planetary Research in Berlin. He’s the experiment leader on the Heat Flow and Physical Properties Package (HP3), the self-hammering “mole” designed to dig down as much as 16 feet (5 meters) and take Mars’ temperature.

“This GIF shows NASA InSight’s heat probe, or “mole,” digging about a centimeter (half an inch) below the surface last week. Using a technique called “pinning,” InSight recently pressed against the mole using a scoop on its robotic arm to help the self-hammering heat probe dig so that it can “take the temperature” of Mars.” Credits: NASA JPL

but then it went into reverse:

NASA/JPL:

After making progress over the past several weeks digging into the surface of Mars, InSight’s mole has backed about halfway out of its hole this past weekend. Preliminary assessments point to unusual soil conditions on the Red Planet. The international mission team is developing the next steps to get it buried again.

A scoop on the end of the arm has been used in recent weeks to “pin” the mole against the wall of its hole, providing friction it needs to dig. The next step is determining how safe it is to move InSight’s robotic arm away from the mole to better assess the situation. The team continues to look at the data and will formulate a plan in the next few days.

“In this image from Oct. 26, 2019 — the 325th Martian day, or sol, of the mission — InSight’s heat probe, or “mole,” is seen after backing about halfway out of the hole it had burrowed.” Credits: NASA, JPL

** Latest on Curiosity’s travels:

“NASA’s Curiosity rover took this selfie on Oct. 11, 2019, the 2,553rd Martian day, or sol, of its mission. The rover drilled twice in this location, which is nicknamed “Glen Etive.” Credit: NASA/JPL-Caltech/MSSS“

** Glacier movements over the eons create striking structures at Euripus Mons: Ancient glacier flows on Mars | Behind The Black

You can see that this large apron is the result of repeated flows down from the mountain, with each new flow not quite traveling as far, creating a terraced slope extending many miles.

Euripus Mons glacier. HiRISE image cropped by Bob Zimmerman

== Amazon Ad ==

Moon: An Illustrated History:
From Ancient Myths to the Colonies of Tomorrow)

Astronomy, Mars, Solar Science, Space Science, The Moon

Space sciences roundup – Oct.18.2019

October 18, 2019 TopSpacer

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.

Milky Way galaxy's gas recycling — “This illustration envisions the Milky Way galaxy’s gas recycling above and below its stellar disk. Hubble observes the invisible gas clouds rising and falling with its sensitive Cosmic Origins Spectrograph (COS) instrument. The spectroscopic signature of the light from background quasars shining through the clouds gives information about their motion. Quasar light is redshifted in clouds shooting up and away from the galactic plane, while quasar light passing through gas falling back down appears blueshifted. This differentiation allows Hubble to conduct an accurate audit of the outflowing and inflowing gas in the Milky Way’s busy halo — revealing an unexpected and so-far unexplained surplus of inflowing gas. Credits: NASA, ESA and D. Player (STScI)”

The Moon

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

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.

Chandrayaan2 Orbiter High Resolution Camera — First images released from the Orbiter High Resolution Camera on the Chandrayaan-2 lunar orbiter. Credits: ISRO

Space sciences roundup – June.5.2019

June 4, 2019 TopSpacer

A sampling of recent articles, videos, and images from space-related science news items:

[ Update: The InSight Mars lander team has come up with a plan for diagnosing and then testing a possible fix for the ground temperature probe that is stuck at a depth that is too shallow to do its job correctly: InSight’s Team Tries New Strategy to Help the ‘Mole’ | NASA

More details on the problem in this earlier report: More Testing for Mars InSight’s ‘Mole’ – NASA’s InSight Mars Lander

]

** A binary asteroid zipped past earth recently: Binary asteroids, key to Earth’s planetary defence – ESA

Humankind has had its closest look yet at a binary asteroid. As 1999 KW4 skimmed past our planet at 70 000 km/h, the most advanced visible-light telescope on Earth resolved the 1.3-km diameter asteroid and its 360-m sized moon. An even closer spacecraft-based encounter will come next decade, when NASA will send a probe to deflect the moon of the distant Didymos binary. Then ESA’s Hera mission will perform a follow-up survey right down to the body’s surface.

The International Asteroid Warning Network (IAWN) coordinated a cross-organisational observing campaign of the asteroid 1999 KW4 as it flew by Earth, reaching a minimum distance of 5.2 million km on 25 May. Since its orbit is well known, scientists were able to predict this flyby and prepare the observing campaign.

Side by side observation and artist's impression of Asteroid 199 — “The unique capabilities of the SPHERE instrument on ESO’s Very Large Telescope have enabled it to obtain the sharpest images of a double asteroid as it flew by Earth on 25 May. While this double asteroid was not itself a threatening object, scientists used the opportunity to rehearse the response to a hazardous Near-Earth Object (NEO), proving that ESO’s front-line technology could be critical in planetary defence. The left-hand image shows SPHERE observations of Asteroid 1999 KW4. The angular resolution in this image is equivalent to picking out a single building in New York — from Paris. An artist’s impression of the asteroid pair is shown on the right.” – ESA

** Update on Japan’s Hayabusa2’s visit to Ryugu, a near-earth asteroid: Hayabusa2 drops second target marker, targets artificial crater for sample collection | The Planetary Society

Japan’s Hayabusa2 spacecraft has successfully dropped a second target marker on Ryugu. The reflective softball-sized sphere, which contains the names of Planetary Society members and other supporters, will give the spacecraft a visual guide if mission planners send it back to the surface to attempt a second sample collection.

JAXA is now considering collecting the sample directly from the area where Hayabusa2 created an artificial crater in early April, thanks to updated imagery collected during an aborted touchdown marker drop attempt in mid-May.

Hayabusa2 second target marker drop — “Hayabusa2 drops its second marker on asteroid Ryugu from an altitude of about 10 meters on 30 May 2019. These images were taken from altitudes between 10 and 40 meters.” Credits: JAXA, Chiba Inst. of Tech. Via The Planetary Society

** Comets provided earth with much of its water: Comet Provides New Clues to Origins of Earth’s Oceans – NASA JPL

The mystery of why Earth has so much water, allowing our “blue marble” to support an astounding array of life, is clearer with new research into comets. Comets are like snowballs of rock, dust, ice, and other frozen chemicals that vaporize as they get closer to the Sun, producing the tails seen in images. A new study reveals that the water in many comets may share a common origin with Earth’s oceans, reinforcing the idea that comets played a key role in bringing water to our planet billions of years ago.

The Stratospheric Observatory for Infrared Astronomy, SOFIA, the world’s largest airborne observatory, observed Comet Wirtanen as it made its closest approach to Earth in December 2018. Data collected from the high-flying observatory found that this comet contains “ocean-like” water. Comparing this with information about other comets, scientists suggest in a new study that many more comets than previously thought could have delivered water to Earth. The findings were published in Astronomy and Astrophysics Letters.

** Jupiter’s magnetic field exhibits unexpected variations over time: Juno space probe identifies changes in Jupiter’s magnetic field – Physics World

An important question for the researchers to answer now is what is the cause of the shift in Jupiter’s magnetic field? On Earth, the change is thought to originate in the planet’s core, however the best explanation for secular variation on Jupiter is in its deep atmospheric (zonal) winds. These winds extend up to 3000 km into the surface of the planet, where the conductive metal fluid is situated. Although the origin of zonal winds is still uncertain, they are believed to interrupt the magnetic field distribution.

The discovery will likely have implications for the study of our Solar System. Kimee Moore, a graduate student from the University of Cambridge and lead author of the report on the findings, says that in the future “scientists will be able to make a planet-wide map of Jupiter’s secular variation” and this latest finding may even help “scientists studying Earth’s magnetic field, which still contains many mysteries to be solved”

** Latest on the Sun’s spot count: Sunspot update May 2019: The long ramp down | Behind The Black

The Sun in May continued to show the exact same amount of activity as it had shown for March and April. This steady uptick in sunspot activity once again shows that the ramp down to full solar minimum will be long and extended.
…
That we are definitely ramping downward to minimum, even with the slight increase in the past three months, is shown by the fact that the Sun has shown no sunspots for the past fifteen days. In fact, all the activity shown in May comes from the first half of the month. This pattern is actually a reflection of the Sun’s 27-day rotation period. …

** A film of a solar eclipse in 1900 was found and restored: First movie of solar eclipse rediscovered | Behind The Black

The magic of a real solar eclipse filmed on 28 May, 1900 by a famous magician, Nevil Maskelyne, while on an expedition by The British Astronomical Association to North Carolina. In 1898 he travelled to India to photograph an eclipse. He succeeded but the film can was stolen on his return journey home.

It was not an easy feat to film. Maskelyne had to make a special telescopic adapter for his camera to capture the event. This is the only film by Maskelyne that we know to have survived. The original film fragment held in The Royal Astronomical Society’s archive has been painstakingly scanned and restored in 4K by conservation experts at the BFI National Archive, who have reassembled and retimed the film frame by frame.

The film is part of BFI Player’s recently released Victorian Film collection, viewers are now able to experience this first film of a solar eclipse since the event was originally captured over a century ago.

** The Stars of Cepheus as seen by NASA’s Spitzer Space Telescope:

Soar through this cosmic landscape filled with bright nebulas, as well as runaway, massive and young stars. The image comes from NASA’s Spitzer Space Telescope, which sees the universe in infrared light. For more about Spitzer, visit https://www.nasa.gov/spitzer or http://www.spitzer.caltech.edu/.

** Mars:

*** An update on Europe’s ExoMars Rover mission, which ESA plans to launch in July 2020 for a landing in March 2021: ESA Prepares for ExoMars Rover 2020 Launch at Mars and on Earth | The Planetary Society

Preparations for the ExoMars rover mission are in their final stages. ESA made two announcements today: ExoMars Trace Gas Orbiter is shifting orbit, and they officially opened a new Rover Operations Control Centre (ROCC) in Turin, Italy. ROCC will support the Rosalind Franklin rover’s deployment from the Kazachok lander and surface operations after that. Along with the announcements they posted some cool images.

*** Ten things about Mars are revealed in an interactive display from ESA.

*** Signs of even more water on Mars:

From Space.com:

Scientists think they’ve stumbled on a new cache of water ice on Mars — and not just any ice but a layered mix of ice and sand representing the last traces of long-lost polar ice caps.

That’s according to new research based on data gathered by NASA’s Mars Reconnaissance Orbiter, which has been circling the Red Planet since 2006 and has just marked its 60,000th trip around Mars. On board the spacecraft is a radar instrument that can see about 1.5 miles (2.5 kilometers) below the planet’s surface — and in that data, scientists see lots and lots of ice.

Alternating ice and sand layers on Mars — “A composite image showing alternating layers of ice and sand in an area where they are exposed on the surface of Mars. The photograph, taken with the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter, was adjusted to show water ice as light-colored layers and sand as darker layers of blue. The tiny bright white flecks are thin patches of frost.” Credit: NASA/JPL/University of Arizona. [Via AGU.org]

*** The Space Show – Fri, 05/24/2019 – Dr. Gilbert Levin and Dr. Patricia Ann Straat talked about the “Viking Labeled Release experiment, life detection on Mars, From Mars With Love by Dr. Straat and more”.

*** Mars reports from Bob Zimmerman:

**** Rover update: May 30, 2019 – Latest on Curiosity’s explorations (and also an update on China’s Yutu-2 rover on Moon). The image below

… one of a number taken by the rover in the past week, showing water clouds drifting over Gale Crater.

Mars clouds as seen by Curiosity — *Mars clouds over Gale crater as seen by Curiosity. Via Behind the Black.*

According to NASA JPL:

These are likely water-ice clouds about 19 miles (31 kilometers) above the surface. They are also “noctilucent” clouds, meaning they are so high that they are still illuminated by the Sun, even when it’s night at Mars’ surface. Scientists can watch when light leaves the clouds and use this information to infer their altitude.

But Curiosity wasn’t just looking at the clouds:

While these clouds teach us something about Martian weather, the big rover news this week was that the data obtained from the two drill holes taken in April show that the clay formation that Curiosity is presently traversing is definitely made of clay, and in fact the clay there has the highest concentration yet found by the rover.

**** Crater? Pit? Volcano? – A puzzling feature might be an impact crater but maybe not:

I would not bet much money on this conclusion. The overall terrain of the Eridania quadrangle is filled with craters, large and small. There does not seem to be any obvious evidence of past volcanic activity, and if there had been it has not expressed itself in large volcanoes.

Eridania crater — *This circular feature in the Eridania region could be a meteoroid crater or a volcano caldera. Via Behind the Black.*

However, other images of this mountain show many circular features that at first glance appear to be craters like the featured image. They appear slightly raised above the surrounding terrain, though not in as pronounced a manner.

They all could be small volcanoes. Or maybe they are impacts that hit a dense surface which prevented them from drilling too deep down, and instead caused the crater to be raised above the surrounding terrain.

‘Tis a puzzle. The irregular pit in this particular feature adds to the mystery. It does not look like the kind of pits one sees in calderas. Instead, its rough edge suggests wind erosion.

**** The mysterious slope streaks of Mars – Streaks on the sides of sloped surfaces are puzzling…

… and appear to possibly represent a phenomenon entirely unique to Mars. I became especially motivated to write about these mysterious ever newly appearing features when, in reviewing the May image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I found four different uncaptioned images of slope streaks, all titled “Slope Stream Monitoring.” From this title it was clear that the MRO team was re-imaging each location to see if any change had occurred since an earlier image was taken. A quick look in the MRO archive found identical photographs for all four slope streak locations, taken from 2008 to 2012, and in all four cases, new streaks had appeared while older streaks had faded.

*Example of streaks on Martian slopes. Via Behind the Black*

====

Brief Answers to the Big Questions
– Stephen Hawking

Astronomy, Solar Science, Space industry and microgravity R&D

Space sciences roundup – May.10.2019

May 10, 2019 TopSpacer

A sampling of recent articles, videos, and images from space-related science news items:

** Experiments designed and built by students were among the 38 R&D payloads on the recent Blue Origin New Shepard flight to 106 km:

For example, the UCLA team of 11 students designed and built an experimental magnetic pump named Blue Dawn that will work in zero-gravity:

“The goal was to see if we could design an efficient fluid pump without any moving parts to work in zero-gravity, which has never been done before,” said Alexander Gonzalez, fourth-year physics major and undergrad science lead on the project. Such a low-maintenance pump would be ideal for moving various liquids on the International Space Station, and could reduce the risk of motorized pump failures for rovers and even future bases on the moon or Mars.

** Living tissues embedded in 3D electronics chips were among the research projects on the recent SpaceX Dragon Cargo mission to the ISS. The company Emulate, Inc. sent “organs-on-chips” to the ISS to study the Effects of Microgravity on Human Physiology including

the effect of microgravity and other space-related stressors on the brain blood barrier. It uses fully automated tissue chip technology, a Brain-Chip, consisting of living neuronal and vascular endothelial cells in a micro-engineered environment. Results may provide insight into the relationship between inflammation and brain function and a better understanding of neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

More about tissue chip research in microgravity:

** The latest sunspot count: Sunspot update April 2019: Not quite minimum | Behind The Black

As the Sun ramps down to minimum it will have months where there is no activity, as happened in February 2019, and months, such as in March and April, where more sunspots appear.

Eventually the quiet months will become dominate, and soon thereafter, when activity increases again (assuming it does), the solar science community will then announce the date of true minimum.

We are not there. Normally it can take a year or more for the Sun to settle down. If activity declines as indicated by the red curve, it could take as long four years, which would be a record-long minimum. The difference will tell us whether the eleven-year solar cycle is continuing, or the Sun is heading into a grand minimum, with no significant sunspots for decades.

** Measuring the magnetism of Mars and Jupiter were discussed on the recent TMRO.tv episode Orbit 12.15:

NASA’s MAVEN Magnetometer Instrument Lead Dr. Jared Espley joins us to talk about MAVEN, Juno and how we measure the magnetism of planets in our local system. More information on MAVEN can be found here: https://www.nasa.gov/mission_pages/ma… And more information on Juno can be found here: https://www.nasa.gov/mission_pages/ju…

Dolphin spotted on Jupiter…@NASAJuno Perijove 16 [ Eichstädt / Doran ] pic.twitter.com/GzoGASVMya

— Seán Doran (@_TheSeaning) May 2, 2019

** The mystery of Mars water remains unsolved: Mars Used to Have Water, But We Can’t Explain How | The Planetary Society –

Mars has been the most extensively studied planet in the Solar System, except of course Earth. For the last 25 years, these missions have focused on the search for life by “following the water.” Although we have acquired compelling evidence of flowing liquid water on early Mars, the fundamental question about how water could be stable under Martian atmospheric conditions remains unsolved. Everything we have learned about Mars points towards a freezing cold Martian climate that would be incapable of stabilizing liquid water throughout Mars’ history.

** Even dry asteroids contain water in our wet solar system: Water has been found in dust of an asteroid thought to be bone-dry | Science News

Grains of dust from the asteroid Itokawa actually contain a surprising amount of water, two cosmochemists from Arizona State University in Tempe report May 1 in Science Advances.

“We didn’t really expect water to be there in Itokawa at all,” says study coauthor Maitrayee Bose. But if similar asteroids have similar amounts of water, the space rocks could have been a major source of water for the early Earth.

** More cave openings spotted on Mars and analyzed by Bob Zimmerman: The many pits of Arsia Mons | Behind The Black

*Arsia Mons pits 2019. Credits Behind-the-Black*

The many pits surrounding Arsia Mons highlight a far greater mystery about Martian geology. Some geologists believe that the many meandering channels we see on Mars could have formed not from surface flow as generally assumed but by underground drainage that washed out voids below the ground which in turn caused the surface to subside, forming those meandering channels.

Yet, as far as I can tell, the only place where scientists have been able to identify a significant number of potential cave openings are on the volcanic slopes of Arisa Mons and its neighboring giant volcanos. There are exceptions, such as this spectacular pit at the head of a channel in the transition zone between the southern highlands and the northern lowlands, as well as two different pits, here and here, that are located in the lowlands in Utopia Basin. Overall however the bulk of pits imaged by MRO appear to be on the slopes of the giant volcanoes, with the majority so far found near Arsia Mons.

** Insight lander images sunrise and sunset on Mars: InSight Captures Sunrise and Sunset on Mars | NASA

A camera on the spacecraft’s robotic arm snapped the photos on April 24 and 25, the 145th Martian day, or sol, of the mission. In local Mars time, the shots were taken starting around 5:30 a.m. and then again starting around 6:30 p.m. As a bonus, a camera under the lander’s deck also caught clouds drifting across the Martian sky at sunset.

Insight captures a sunset. — “NASA’s InSight lander used the Instrument Deployment Camera (IDC) on the end of its robotic arm to image this sunset on Mars on April 25, 2019, the 145th Martian day, or sol, of the mission. This was taken around 6:30 p.m. Mars local time.” Credits: NASA/JPL-Caltech. Full image and caption

** NASA orbiter measures the temperature of Mars moon Phobos: Why This Martian Full Moon Looks Like Candy – NASA JPL –

For the first time, NASA’s Mars Odyssey orbiter has caught the Martian moon Phobos during a full moon phase. Each color in this new image represents a temperature range detected by Odyssey’s infrared camera, which has been studying the Martian moon since September of 2017. Looking like a rainbow-colored jawbreaker, these latest observations could help scientists understand what materials make up Phobos, the larger of Mars’ two moons.

Odyssey is NASA’s longest-lived Mars mission. Its heat-vision camera, the Thermal Emission Imaging System (THEMIS), can detect changes in surface temperature as Phobos circles Mars every seven hours. Different textures and minerals determine how much heat THEMIS detects.

Such measurements can help determine the composition of the moon, particularly the minerals and metals:

Iron and nickel are two such metals. Depending on how abundant the metals are, and how they’re mixed with other minerals, these data could help determine whether Phobos is a captured asteroid or a pile of Mars fragments, blasted into space by a giant impact long ago.

These recent observations won’t definitively explain Phobos’ origin, Bandfield added. But Odyssey is collecting vital data on a moon scientists still know little about – one that future missions might want to visit. Human exploration of Phobos has been discussed in the space community as a distant, future possibility, and a Japanese sample-return mission to the moon is scheduled for launch in the 2020s.

** Hubble telescope images assembled into a giant mosaic of 265k galaxies: Hubble Assembles Wide View of the Distant Universe | ESA/Hubble

Astronomers developed a mosaic of the distant Universe that documents 16 years of observations from the NASA/ESA Hubble Space Telescope. The image, called the Hubble Legacy Field, contains roughly 265,000 galaxies that stretch back to just 500 million years after the Big Bang.

The wavelength range of this image stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time. The faintest and farthest galaxies in the image are just one ten-billionth the brightness of what the human eye can observe.

“Now that we have gone wider than in previous surveys, we are harvesting many more distant galaxies in the largest such dataset ever produced,” said Garth Illingworth of the University of California, Santa Cruz, leader of the team that assembled the image. “No image will surpass this one until future space telescopes like James Webb are launched.”

This video “takes the viewer on a journey into the Hubble Legacy Field”:

** Tracking Gaia precisely to get precise locations of a billion stars: Pinpointing Gaia to Map the Milky Way | ESO

This image, a composite of several observations captured by ESO’s VLT Survey Telescope (VST), shows the ESA spacecraft Gaia as a faint trail of dots across the lower half of the star-filled field of view. These observations were taken as part of an ongoing collaborative effort to measure Gaia’s orbit and improve the accuracy of its unprecedented star map.

This image, a composite of several observations captured by ESO’s VLT Survey Telescope (VST), shows the space observatory Gaia as a faint trail of dots across the lower half of the star-filled field of view. These observations were taken as part of an ongoing collaborative effort to measure Gaia’s orbit and improve the accuracy of its unprecedented star map.

Gaia, operated by the European Space Agency (ESA), surveys the sky from orbit to create the largest, most precise, three-dimensional map of our Galaxy. One year ago, the Gaia mission produced its much-awaited second data release, which included high-precision measurements — positions, distance and proper motions — of more than one billion stars in our Milky Way galaxy. This catalogue has enabled transformational studies in many fields of astronomy, addressing the structure, origin and evolution the Milky Way and generating more than 1700 scientific publications since its launch in 2013.

In order to reach the accuracy necessary for Gaia’s sky maps, it is crucial to pinpoint the position of the spacecraft from Earth. Therefore, while Gaia scans the sky, gathering data for its stellar census, astronomers regularly monitor its position using a global network of optical telescopes, including the VST at ESO’s Paranal Observatory [1]. The VST is currently the largest survey telescope observing the sky in visible light, and records Gaia’s position in the sky every second night throughout the year.

** A Galaxy Grouping in 2D and 3D: Stephan’s Quintet;

In 1877, Edouard Stephan discovered a tight visual grouping of five galaxies located in the constellation Pegasus. The galaxies of Stephan’s Quintet are both overlapping and interacting, and have become the most famous among the compact groups of galaxies. Astronomers have long known that four of the galaxies (all of which are yellowish-white in this video) form a physical group in space, while the fifth (bluish) is a foreground galaxy. In addition, a sixth galaxy (yellowish-white and on the far left) is likely to be part of the physical grouping. Hence, this 2D quintet that is a 3D quartet may actually be a 2D sextet that is a 3D quintet.

This visualization makes apparent the spatial distribution of these galaxies. The video starts with a view that matches our 2D perspective. As the sequence travels in 3D, the foreground blue spiral, NGC 7320, quickly passes by the camera. The possible sixth galaxy member on the left, NGC 7320C, is seen at roughly the same distance as the remaining four galaxies. The camera turns to pass between two strongly interacting galaxies, NGC 7319 (left) and NGC 7318B (right), with each galaxy’s spiral structure distorted by the gravitational interaction. In contrast, NGC 7318B overlaps in 2D with the more distant elliptical NGC 7318A, but does not have a strong interaction. The other elliptical, NGC 7317, is also seen as more distant than the strongly interacting pair. In 3D, the four or five galaxies in this group are gathered together by their mutual gravity, and may collide and merge together in the future.

Credits: G. Bacon, J. DePasquale, F. Summers, Z. Levay (STScI)

====

Outpost in Orbit: A Pictorial & Verbal History of the Space Station