The NASA InSight Lander’s Historic Journey across Mars comes to an End

by Rida Fatima

After gathering unprecedented scientific data on Mars for over 4 years, NASA’s InSight project has officially come to a conclusion.

InSight Lander’s Historic Journey
(Figure 1: An Image of The NASA InSight Lander (Source: NASA/JPL-Caltech/SWNS))

Recently, the “InSight” Mars lander from NASA posted its formal farewell statement on Twitter, tearing at people’s heartstrings all across the world. The InSight lander from NASA, famed for taking the very first “selfie” on Mars, is about to shut down and lose touch with Home. It is unable to recharge since the solar panels on its roof are covered in a heavy layer of Martian dirt.

The Inner Workings of the InSight Lander

“InSight” stands for “Interior Exploration Using Seismic Investigations, Geodesy, and Heat Transport”. Over time, Mars’ seismic activity and meteorological fluctuations were observed by the many probes and measurement tools. Researchers can better grasp Mars’ interior, particularly the mantle and crust, thanks to details relating seismic quakes on Mars.

In November 2018, the robotic geologist initially landed on the desolate stretch of Elysium Planitia, carrying a hammer and a seismic meter. Jim Green, the lead researcher at NASA, stated before its 2018 flight that the operation’s basic significance to is comprehend the origins of our planetary system and how it evolved into what it is presently. Since then, it has conducted geological digs and used a cutting-edge seismograph that was set up right on planet mars’ surface to take the initial readings of seismic activities.

The Findings of the InSight Lander

It’s extremely precise seismometer, along with continuous surveillance by the French space program Centre National d’Etudes Spatiales (CNES) and the Mars-quake Service run by ETH Zurich, picked up 1,319 mars-quakes, notably seismic events brought on by meteorite strikes, the greatest among which the year before exposed boulder-size ice fragments. These hits aid in establishing the planetary surface’s age.

Based on released campaign statistics, Insight has monitored over 1,300 quakes ever since it was deployed, and over 50 of them produced signatures that were sufficiently distinct for researchers to determine their position on the Martian surface.

The lander’s findings have also revealed information concerning the strata of Mars’ subsurface, its liquid core, the remarkably changeable remains of its largely defunct magnetosphere underneath the surface, weather, and earthquake activities.

The Challenges Faced by InSight during its Mission

InSight had a lot of difficulties while on its journey. The Self-hammering spike on the lander, dubbed “the mole,” was designed to burrow 16 feet (5 meters) deep while tethering sensors to monitor heat on the planet, allowing researchers to determine how much energy was left over from Mars’ birth.

The mole struggled to get footing in the unusually crumbly soil surrounding InSight because it was made for the open, granular soil encountered on prior expeditions. The device, which was made possible by the German Aerospace Center (DLR), ultimately sank its 16-inch (40-centimeter) probe close to the surface while gathering important information about the thermal and physical characteristics of the Martian surface. This will be helpful for upcoming human and robotic expeditions which aim to probe Martian soil.

Owing to JPL and DLR engineers’ creative use of the lander’s mechanical arm, the operation effectively buried the mole. The arm and its scoop were originally designed to place scientific equipment on the Surface of the planet, but as energy started to run low, they eventually assisted in cleaning debris from InSight’s solar panels.

The Final Moments of InSight’s Mission

“We’ve thought of InSight as our friend and colleague on Mars for the past four years, so it’s hard to say goodbye,” said Bruce Banerdt of JPL, the mission’s principal investigator. “But it has earned its richly deserved retirement.”

The solar-powered lander issued an update last month, reminiscing on its time in space:

“I’ve been lucky enough to live on two planets. Four years ago, I arrived safely at the second one, to the delight of my family back on the first. Thanks to my team for sending me on this journey of discovery. Hope I’ve done you proud.”

NASA made the decision to wait till InSight failed 2 check-ins with the satellite circling Mars which transmits its data to Earth before calling the operation complete.

The solar-powered lander’s surroundings were clouded by a strong dust storm that obscured the sunlight and left a shadowed picture with white specks from camera noise. Prior to the entire image being relayed, the communication was interrupted.

After making a couple of efforts to communicate with the lander, project commanders at the company’s Jet Propulsion Laboratory (JPL) in Southern California came to the conclusion that the rover’s solar-powered battery had run out of energy, a condition known to engineers as “dead bus.”

The space program issued a warning in November that the rover’s lifespan could be running out as debris proceeded to gather and suffocate the InSight’s energy.

The lander’s ability to generate electricity continuously decreased as the layer of wind-blown dirt on its solar panels increased, according to a 2 November statement from NASA. The conclusion of the expedition, according to NASA, was anticipated to occur within the coming weeks.

The InSight lander's dome-covered seismometer
(Figure 2: The InSight lander’s dome-covered seismometer seen on the surface of Mars as the spacecraft loses power. (Source: NASA InSight Twitter account))

On Monday, NASA’s official InSight twitter account released the following statement:

“My power’s really low, so this may be the last image I can send. Don’t worry about me though: my time here has been both productive and serene. If I can keep talking to my mission team, I will – but I’ll be signing off here soon. Thanks for staying with me.”

NASA had originally determined to end the project if the rover didn’t respond to 2 attempts at contact. Although it is thought to be improbable at this stage, the organization will continue its attempts to search for a message from the rover. Dec. 15 marked the final moment InSight spoke with Earth.

“InSight has more than lived up to its name. As a scientist who’s spent a career studying Mars, it’s been a thrill to see what the lander has achieved, thanks to an entire team of people across the globe that helped make this mission a success,” said Laurie Leshin, director of JPL, who was in charge of managing the expedition “Yes, it’s sad to say goodbye, but InSight’s legacy will live on, informing and inspiring.”

Sources

Synthetic Biology For The Improvement of Manned Space Missions In Space

by Rida Fatima

Synthetic Biology
(Figure 1: After humans reach an extraterrestrial destination, microbial-based biomanufacturing might change everything and become a key source of making life interplanetary. (This photo is provided by Royal Academy Interface))

As humans enter a new era of exploring the cosmos to know what lies beyond our sky, there are many challenges they must overcome. New technologies are being brought to light by the innovators of science to allow them to travel further from planet Earth. Space synthetic biology is a promising life support approach, that minimizes the payload launched and increases reuse and recycling. It also uses local resources for the creation of essential products needed by the astronauts aboard ISS. The application of synthetic biology in space exploration is the key to future manned space missions.

Target Areas For Synthetic Biology In Space

The 4 main target areas on which scientists are focusing are how synthetic biology can make fuel generation, biopolymer synthesis, food production, and pharmaceutical manufacture more effective and efficient. Microbial biomanufacturing also has a lot of significance as it can lower the mass of manufactured fuel by 56%. In addition, bacteria might entirely restock exhausted or contaminated medicinal supplies, enabling independence from the resupply cargo missions that take up to 210 days to reach Mars.

Mars Food Production, augmented by Synthetic Biology
(Mars Food Production, augmented by Synthetic Biology (dall-e))

Synthetic Biology Application For Rocket Fuel

Using biotechnology, scientists have developed a strategy for producing crucial propulsion fuel for the journey to Mars. This study seeks to provide numerous significant benefits over existing proposed ways for producing Mars rocket fuel. Considerable synthesis of biological propellants is projected to become a vital technology for future Mars exploration missions.

As the cost of launching and sending payload to Mars is extremely expensive, it makes sense to manufacture some of the needed fuel in space instead of bringing it all from Earth. The generation of a methane-oxygen fuel mixture is being planned by utilizing carbon dioxide, it will be needed for the return trip from Mars. Apart from this, recently another fuel blend idea has gained attention due to its efficiency and safety. It involves blending nitrous oxide along with a few specific hydrocarbons, though studies and research are still going on to check how this blend can be generated in space. Here, synthetic biology is helping in two ways; if a methane-oxygen fuel blend is chosen then it will increase the savings. The generation of nitrous oxide hydrocarbon fuel becomes more efficient and suitable.

Manufacturing Of Space Medicine

Drugs have faster expiry in space due to exposure to harmful space radiation. There is a high chance of lowering the tolerability of solid medication formulations by up to 3 quarters. The capacity to synthesise pharmaceuticals in space is very important for astronauts in long-haul space flights. Synthetic biology medication manufacturing is a potential replacement for conventional drug production methods in space. It also significantly minimises the requirement for emergency payload supplies. That’s where Space Synthetic Biology (SynBio) project comes in, which was introduced by NASA for developing technology to produce valuable items such as vitamins and medications on demand.

Astronauts can take the only renewable and natural resource from Earth into space: Cells. It can either be fungi or bacteria cells. They can be repurposed or modified to manufacture specific materials such as bioplastics using synthetic DNA. These bioplastics can then be introduced in 3-D printers to create anything that astronauts may require during their space missions. The constructed material can be anything such as electronic gadgets or medical equipment.

These innovative technologies are still evolving, and a long-duration human space trip is still several years away. An increase in mass savings occurs when the supplied feedstock essential to 3-D print a lunar or Martian habitat is substituted for the shipped mass required to biologically create the feedstock on location. Nevertheless, 3-D printing in space is still new and unproven. Additionally, the production of printer feedstock for this purpose has yet to be thoroughly investigated.

Significant Role In Food Production

The BioNutrients experiment is part of US space agency NASA’s SynBio project. It is located at NASA’s Ames Research Center in California’s Silicon Valley. It will assess and evaluate an in-space nutrient production approach that employs genetically-engineered baker’s yeast and a longer shelf growth substrate. The aim is to produce the antioxidants that are mostly found in carrots, bell peppers, and vegetables. Beta carotene and zeaxanthin are included in such antioxidants.

The first batch of “BioNutrient” was sent to the ISS in April 2019. The length of experiment was decided to be five years by the SynBio team. Dehydrated yeast along with their food source was present in BioNutrient packs. To begin the testing, astronauts aboard the International Space Station added sterile water to the bag. It was thoroughly mixed, and kept in a warm place for 48 hours. It was frozen for further analysis to be done on Earth to check how well the system performed and how much yeast grew in the BioNutrient packets. Not only that, but the SynBio project team is also working on a mechanism that chemically transforms CO2 and H2O into organic molecules that can “feed” microbial biomanufacturing systems. It will also allow them to produce a variety of items like food, medicines, and plastics. This method could be widely used to generate these things in a sustainable manner on Earth.

Future Of Space Synthetic Biology

Space synthetic biology is truly ground-breaking. Abiotic technologies were developed for decades before they were successfully utilized in space, and biological technologies like synthetic biology are only now seeing development efforts. Of course, these technologies have some catching up to do, but it turns out that they may not be too far behind, and in some cases, the technologies may already be superior to their abiotic counterparts. This innovative technological field of science holds great future promise as a new and exciting biotechnology field, with numerous directions for fruitful research that are grounded in technologies already in development today.

Bibliography

NASA ROVER FINDS TRACES OF GREEN SAND ON MARS

by Rida Fatima

Instead of just sedimentary rocks, the Perseverance rover from NASA discovered something
(Fig 1: Instead of just sedimentary rocks, the Perseverance rover from NASA discovered something in the early stages of life in the Jezero Crater on Mars. Jezero Crater on Mars was photographed by NASA’s Perseverance rover.)

Since red rocks and craters can be seen in every Mars image that has been seen by humanity so far, Mars is thought of as a red planet. Scientists did not expect to see anything otherwise when NASA’s Perseverance rover landed in Mars’ Jezero Crater. However, what the rover discovered on the ground was unexpected. As we have seen in the past, Jazero Crater was chosen as the perfect location for the rover to land, as this part of Mars has a very rich river system, magnetic field, air, and liquid water. Two famous planetary researchers in the fields of earth sciences, planetary sciences, and atmospheric sciences are known as Roger Wiens and Briony Horgan, and they have published something very new in the famous journals. According to information released by Purdue University, where these researchers work, the rover was going to witness sedimentary rocks on the bottom side of the lake, but instead, it witnessed something different and unexpected and discovered many of these rocks to be volcanic in origin. According to the university, these rocks were discovered to contain “huge grains of olivine, the muddier, less-gemlike variant of period that colors so many of Hawaii’s beaches rich green” (ABP, 2022).

A tweet by NASA’s official about the Jazero Crater
(Fig 2: A tweet by NASA’s official about the Jazero Crater. Picture Credits: Twitter and NASA.)

They began to notice that the layered igneous rocks we were witnessing did not resemble the igneous rocks found on Earth today. Instead, they resemble the igneous rocks that formed when the Earth first formed, according to Wiens. In order to analyze samples and identify the kind and provenance of the rocks, the SuperCam on Perseverance was designed and built under Wiens’ direction. Horgan, on the other hand, assisted in deciding on Jezero Crater as the rover’s landing spot. The rocks and lava that the rover on Mars is examining are almost 4 billion years old, according to the experts. The fact that our planet has active tectonic plates, in addition to the weathering impacts of wind, water, and life over billions of years, means that while such ancient rocks have been discovered, they are severely weather-beaten. But on Mars, these rocks are pure, making it far simpler to investigate them, the university claimed (ABP, 2022).

The Jezero Crater Surprise

During the spring of 2021, the Perseverance rover from NASA started studying the rocks in Jezero Crater on Mars. When the rover communicated what they had discovered, scientists were taken aback. Since the location once hosted a lake, sedimentary rock that formed when sand and mud settled in the wet environment was expected to be there. Instead, the rover found that the floor was composed of two different types of igneous rock, one of which was generated by magma deep beneath and the other by volcanic activity on the surface, according to NASA. Because the crystals in igneous rocks preserve a wealth of information regarding the precise moment of their formation, they are regarded as excellent timekeepers.

According to a NASA blog post by Ken Farley of Caltech, the project scientist for Perseverance and the author of the aforementioned Science publication, “The igneous rocks we obtained will tell us approximately when the lake was existing in Jezero. We are aware that it predates the formation of the igneous crater floor rocks.” He said that this would answer several important concerns, such as when Mars’ environment was suitable for lakes and rivers and when it reverted to the extremely chilly and dry conditions that exist today. The hunt for life is one of Perseverance’s primary professed objectives. However, igneous rock isn’t the best material for preserving any potential traces of prehistoric microscopic life that the rover may find, according to NASA, because of the manner it was generated. On the other hand, sedimentary rock frequently originates in wet settings that are favorable for life, making it better at preserving early indications of life. Sedimentary rock’s age might be difficult to ascertain, especially if it includes fragments that were produced at several points before the sediment was deposited (ABP, 2022).

According to NASA, this is why scientists found the sediment-rich river delta that the rover has been exploring since April 2022 to be particularly “tantalising.” We observed these rocks from orbit and said, “Oh, they have gorgeous layers! We therefore assumed that they were sedimentary rocks. We didn’t realise that these are not sedimentary rocks until we were up close and examined them at the millimetre scale. Actually, these are old lava. We had a major breakthrough when we discovered it on the ground, and it amply demonstrated the need for this kind of exploration”, according to Horgan, who was quoted by Purdue.

Scientists have high hopes for the sedimentary rocks that Perseverance is currently analysing after uncovering the potential for habitable conditions in Jezero Crater’s old lava flows, which are currently thought to be uninhabitable (TECH, 2022).

The anticipation for “further greater results about organics and old, livable ecosystems” is expressed by Horgan. “According to my observations, it is really laying the groundwork that the Red Planet is this much of an aqueous, livable planet, and by getting all the samples back, it will lead us to understand even better the chemistry of ancient microbial life that is existing on the Red Planet,” the researcher says. Furthermore, NASA is still collecting major samples of the sedimentary rocks, which will be returned to Earth by the Mars Sample Return campaign, and further analysis will be done in well-equipped labs.

References

A “Forest Bubble” On Mars? Scientist Proposes Ambitious Plan For Sending Wildlife To Mars

by Rida Fatima

Forest Bubble on Mars
(Figure 1: 3D Illustration of a Mars outpost colony with a geodesic dome. Credit: https://interestingengineering.com/)

A report from the CNET network reveals that a detailed proposal has been made by a botanist and an ecologist for a flourishing green space on the desolate and barren surface of Mars. The ENTR, abbreviated as “extraterrestrial nature reserve,” would appear as a “forest bubble” resembling a greenhouse that was created to replicate Earth’s biosphere on the red planet (Young, 2022). Ultimately, it would make life easy and allow the earthlings to feel like home on Mars and also for the early inhabitants it will act as sustainable source of raw material and as well as source of food to survive in a proper manner.

Aspire to make an Earth-like Environment on Red planet

Paul Smith, a botanist from the University of Bristol, outlined the plan for developing a thriving, controlled ecosystem on Mars in a study that was published in one of the most authentic journals related to Astrobiology research last month. The study begins by summarizing the difficulties colonists will face on the Red planet, which includes a difficult environment that is inhospitable for human beings, as well as radiation and less favorable sunshine than on planet Earth. The botanist also argues that some Earth species may be able to adapt to life on the red planet despite these difficulties (Young, 2022).

According to Smith, Mars might support a variety of fauna, including fungi, invertebrates like earthworms and spiders, and soil bacteria. If we talk about the plants such as junipers and birches it would be very hard for them to survive in such an environment with a little amount of sunlight, as for the flora. Smith underlined the need to avoid trying to recreate a copy of a forest which completely resembles the forests on Earth on mars because doing so would prevent nonhuman species like raccoons, fish, and birds from being able to live in their natural habitats. According to Smith, “ETNR designers should take species into account as ecological cogs that may be assembled into functional ecosystems.” While it is now impossible to replicate Earth’s forests, it is possible to create new ecosystems that function in novel ways.

A “Futuristic Noah’s Ark”- Style Starship

Although Smith acknowledges in his article that he hasn’t thought about the enterprise’s finances, the idea of a Mars ecosystem that delivers life outside for humans on the red planet is one that is attractive. Prior to its first orbital trip, SpaceX recently tested the Starship prototype’s static fire capability. The business is working on an entirely reusable Starship spacecraft to make the flight to space within a reasonable budget and enable human journeys to the Red Planet. But it doesn’t mean it won’t be a very expensive endeavor for people and freight, let alone animals (HeadTopics, 2022).

However, according to Smith’s concept, little invertebrates would be the most suitable for a Martian ecology because they would weigh little and might be able to travel with other cargo. The ETNR is also described in Smith’s plan as a possible option for some species to survive. “If the population of humans continues to rise on Earth, natural places will have to be sacrificed.” Another option is to terraform Mars to add more habitats. All of this is consistent with Elon Musk’s lofty plan for Starship, which he compared to a “futuristic Noah’s Ark” earlier this year. But first, SpaceX needs to launch its enormous reusable spacecraft into orbit (Young, 2022).

References

Peekaboo Galaxy Emerges From Hiding, Offering A Direct Window Into The Past

by Rida Fatima

NASA's Hubble Space Telescope managed to capture a comprehensive picture of the tiny galaxy HIPASS J1131-31
(Figure 1: Despite its proximity to a bright foreground star, NASA’s Hubble Space Telescope managed to capture a comprehensive picture of the tiny galaxy HIPASS J1131-31, also termed the “Peekaboo Galaxy.” Aside from Hubble images, astronomers used the South African Large Telescope to collect detailed spectroscopic data on the galaxy’s stars. Through this approach, it was revealed that Peekaboo is one of the tiniest chemically enriched galaxies ever noticed in the local universe. Credits: NASA, ESA, and Igor Karachentsev (SAO RAS); Image Processing: Alyssa Pagan (STScI))

A Peek Into The Past

A galaxy named HIPASS J1131-31, or Peekaboo has now come into view through an incredible picture captured by the Hubble Space Telescope. The Peekaboo galaxy is only 22 million light-years away from the Milky way galaxy. More than 20 years ago, Astronomers first detected the presence of this galaxy with the help of Australian Parkes radio telescope Murriyang, since then it was not quite visible for observation as its view was hidden by a bright star (TYC 7215-199-1) in the Milky Way. According to research, the HIPASS J1131-31 galaxy is the nearest example of the galaxy formation and development processes that occurred shortly after the big bang, which was around 13.8 billion years ago.

“Uncovering the Peekaboo Galaxy is like discovering a direct window into the past, allowing us to study its extreme environment and stars at a level of detail that is inaccessible in the distant, early Universe,” – Astronomer Gangadeep Anand

Peekaboo galaxy is described as “extremely metal-poor” by astronomers (XMP). In the beginning, the universe was constituted primarily of primitive hydrogen and helium, these were the elements created during the big bang. Throughout cosmic history, these elements formed stars that begin producing much heavier elements, eventually leading to the metal-rich universe of today. Carbon, oxygen, iron, and calcium are heavier elements “basic building blocks” that make up life as we know it. These elements were distributed throughout the universe after the supernova of metal-poor stars. Low metallicity in a galaxy is of particular interest to astronomers. It may provide critical insights not only into the chemical evolution of stars but also highlights the astrophysical events occurring in the expanding universe.

What Makes ‘Peekaboo Galaxy’ Different From Others?

Metal-poor galaxies are not very rare in the universe as they have already been discovered in our local galaxy by astronomers. However, Peekaboo is distinctive in two major ways. Firstly, it is much closer consisting of at least half the distance between it and formally known related galaxies. Moreover, it’s a metal-poor galaxy with no older stars nearby. Professor Bärbel Koribalski is an astronomer and a research scientist at Australia’s national science agency CSIRO. She is also the co-author of the latest research study on Peekaboo’s metallicity.

The Hubble telescope was able to study the composition of approximately 60 stars in the Peekaboo galaxy. Almost all of these stars appeared to be a few billion years old or younger. The Southern African Large Telescope (SALT) measurements of Peekaboo’s metallicity managed to complete the snapshot. The significant difference between HIPASS J1131-31 and other galaxies in the known universe was highlighted by these findings. Other galaxies typically have stars that seem to be billions of years old. As determined by the stars in Peekaboo, it is the youngest and slightly chemically-enriched galaxy ever revealed in the local universe. This is exceedingly rare, given that the local universe has had roughly 13 billion years to build the cosmic historical background.

Koribalski said while talking about the Peekaboo, “In the start, we were unaware of how special this little galaxy was, but now we know that the Peekaboo Galaxy is one of the most metal-poor galaxies ever detected, all credits go to data collected from the Hubble Space Telescope, (SALT) the Southern African Large Telescope, and others.”

“Because Peekaboo is so close to us, we can conduct detailed observations, allowing us to see an atmosphere like the early universe in extraordinary detail,” the astronomer Gangadeep Anand concluded.

Conclusion

Professor Bärbel discovered HIPASS J1131–31 or the Peekaboo galaxy as a region of cold hydrogen, as mentioned above. The discovery took place 20 years ago. Later on, NASA’s space-based Galaxy Evolution Explorer mission identified Peekaboo to be a compact blue dwarf galaxy using far-ultraviolet observational data. Now, Astronomers will be using the James Webb Space Telescope (JWST) alongside the Hubble Space Telescope to keep improving the snapshot of HIPASS J1131-31 obtained by Hubble findings as part of Every Known Nearby Galaxy Survey.

Bibliography

FAINT GLOW WITHIN GALAXY CLUSTERS ILLUMINATES DARK MATTER

by Rida Fatima

The Abell S1063 cluster contains a vast number of galaxies
(Fig 1: The Abell S1063 cluster contains a vast number of galaxies, and Hubble’s exceptional sensitivity and resolution have been able to catch an intracluster light, a gentle blue haze. The stars that are responsible for this glow have been expelled from their galaxy. These stars are no longer members of a galaxy and now lead solitary lives, aligning themselves with the gravitational pull of the larger cluster. Intracluster light has been discovered to be a good predictor of the distribution of dark matter in the cluster because of its association with a map of mass distribution in the cluster’s general gravitational field. Credits: NASA and M. Montes.)

The dark matter has enigmatic nature, the unobservable substance which forms most of the cosmos, may be revealed by a fresh study of Hubble photographs of galaxies. It is proved by the astronomers that the diffuse glow that exists between the galaxies in a cluster, also known as intracluster light, can help to trace the path of dark matter, and also help to illuminate the distribution pattern more precisely as compared to the current methods which observe and understand the study through X-ray light. Using Hubble’s earlier images of six giant galaxy clusters from the Frontier Fields mission, they were able to accomplish this. Intergalactic interactions that upend their structures result in intracluster light, which is produced as individual stars are liberated from the gravitational grip of their parent galaxy and realigned with the gravity map of the entire cluster. Additionally, the great majority of dark matter is found here. Where galaxies are colliding is visible in X-ray light, but the cluster’s underlying structure is not revealed. As a result, it is not very authentic and precise to trace the paths of dark matter.

“As the intracluster light is relatively free-floating on the gravity of the cluster itself, which leads it to follow the same gravity, this particular reason makes intracluster light the best way to trace the dark matter in the solar system,” says co-author Mireia Montes. Additionally, we have discovered this precise method to predict the location of the dark matter because we have found a new method to determine the placement of the dark matter as you are monitoring the identical gravitational potential. Our ability to locate dark matter is made possible by a very faint light. (NASA, 2018).

Intracluster Light In The Detection Of Dark Matter

Montes also emphasises that the technique is not only more accurate but also more effective because it just uses deep imaging as opposed to the more involved, time-consuming spectroscopy techniques. As a result, more clusters and objects in space may be researched in less time, providing more possible information about the composition and behaviour of dark matter. The final nature of dark matter may now be statistically characterised thanks to this technology, Montes stated.

The Canary Islands Institute of Astronomy’s Ignacio Trujillo, who co-authored the report and has worked with Montes on intracluster light studies for many years, stated, “The concept for the research was prompted by examining the pristine Hubble Frontier Field photos. Intracluster light was displayed with unparalleled clarity in the Hubble Frontier Fields.” The pictures were motivating, according to Trujillo. “However, I did not anticipate the results to be so accurate. Exciting possibilities exist for the research opportunities in future for space related projects.

A shape matching metric called Modified Hausdorff Distance is used by the astronomer, which helps with the comparison of the contours of the intracluster light. It also compares the different mass maps of the clusters, which are used as a significant part of the data from the Hubble Frontier Fields project, and is placed in the Mikulski Archive for Space Telescopes (MAST). The MHD is a metric for the distance between two groups. The two-point sets become more equivalent when MHD’s value decreases. Based on archived observations from the Advanced CCD Imaging Spectrometer of the Chandra X-ray Observatory, the analysis’s findings showed that the intracluster light distribution visible in the Hubble Frontier Fields images more closely matched the mass distribution of the six galaxy clusters than did X-ray emission. (NASA, 2018).

: The galaxy cluster MACS J0416.1-2403 also produces a gentle glow of intracluster light
(Fig 2: The galaxy cluster MACS J0416.1-2403 also produces a gentle glow of intracluster light, formed by stars that are not a part of any particular galaxy, amidst the intense light of its component galaxies. Long ago, when the gravitational pull of the cluster tore apart their home galaxies, these stars were dispersed throughout the cluster. Eventually, the wandering stars aligned with the cluster’s general gravitational pull. The feeble light is captured by Hubble’s superior sensitivity and resolution, which is then used to pinpoint the location of unseen dark matter, which dominates the cluster’s gravitational field. Credits: NASA and M. Montes.)

Montes and Trujillo see numerous potentials to broaden their research beyond this initial investigation. They first want to see how well the tracing accuracy holds true before expanding the observing area in the initial six clusters. To expand the data set and validate their results, more research teams’ observation and analysis of galaxy clusters will be a crucial test of their methodology. The WFIRST and the James Webb Space Telescope, which will include far more sensitive instruments for detecting weak intracluster light in the farthest regions of the galaxy, are two strong future space-based telescopes that the astronomers anticipate utilizing the same techniques with.

Conclusion

Trujillo wants to test reducing the method’s scalability from enormous galaxy clusters to solitary galaxies. Exploring the star corona, for example, at galactic sizes would be great. The same concept should, in theory, be true; the celestial bodies that have surrounded the star system as consequences of its blending activity should likewise be tracking its gravity and revealing its dark matter distribution (Kimdeyir, 2018). In order to see the incredibly far-off galaxies beyond them and to understand more about how galaxies have evolved since the early (remote) universe, the Hubble Frontier Fields programme was developed. It was a deep imaging project. In that research, the diffuse intracluster light was a problem since it partially hid the far-off galaxies beyond (Kimdeyir, 2018).

References

NASA Perseverance Mars Rover Examines ‘Tantalizing’ Rock for Evidence of Ancient Life

by Rida Fatima

NASA Perseverance Mars Rover Examines 'Tantalizing' Rock
(Figure 1: Image of “Yori Pass” taken by Hazard-Avoidance Camera (Hazcams) on NASA’s Perseverance Mars rover on Nov. 5, 2022, the 609th Martian day, or sol, of the mission. Credits: NASA/JPL-Caltech)

To seek evidence of ancient microbial life, Perseverance is investigating a spot called Yori Pass located in the Jazero Crater of the Red Planet. Mars once had a dense atmosphere and liquid water running on its surface. However, it has now been a barren wasteland for billions of years. Studies have shown Microbes from Earth could also thrive on Mars for many millions of years. On Mars, the river channels spewed over the crater wall and formed a lake more than 3.5 billion years ago. Water carried minerals from the nearby region into the crater lake. Microbial life might have existed in Jezero during these wet periods. If this is the case, evidence of their remains may be found in lakebed or shoreline sediments.

The Sensational Sandstones on Mars

Scientists are looking for ways to investigate how the Martian environment formed and evolved. Search for signs of past life is at its full pace. Rover is collecting samples of Mars rock and soil that may contain such traces. The region, Yori Pass is located in a long-gone river delta region and at the base of Jezero Crater. The crater is believed to have been flooded with water early in Mars’s history. The delta may have once carried the molecules required for life. After spotting some sensational sandstone, NASA’s Perseverance rover decided to explore Mars’ secrets with much excitement. The rover found some rocks there that have excited scientists back on Earth.

Rock sample collection from the Jazero crater is the primary objective of the Perseverance Mars rover. It has to find any signs that life once existed on the Red Planet. It could be any element, molecule, substance or feature that is characteristic of life. According to NASA, scientists find Yori Pass features to be tantalizing as it is sandstone. Not only that but it is also composed of fine grains that might have come from somewhere else due to flowing water before ending up settling and turning into stones. The geological pieces of evidence are so exciting here for the scientists because they consider these fine-grained rocks to have the best chance of preserving the indication of life. Furthermore, they also contain a higher concentration of clay materials that can protect large organic molecules from harmful UV radiation. Hence, due to the presence of this clay material sandstone molecules remain protected from degradation.

Clues of Ancient Life

Historical confirmations of water on Jazero Crater are the main reason NASA chose it as a landing site for its life-exploring rover. The ancient Mars atmosphere could have supported an underground world overflowing with microbial species. The rover used an abrasion tool to clean off a bit of the rock and look beneath the dusty surface. It uncovered veins of lighter material within the beige surroundings. “Could it hold clues about ancient life?” the Perseverance team tweeted. NASA expects that Perseverance will reveal biosignatures in the Yori Pass rock. This discovery could be defined as “any property, element, molecule, material, or trait that can indicate ancient life.” The rover has recently explored organic compounds in a rock sample, although it is too early to tell if this is proof of microscopic organisms from the red planet’s old days.

Yori Pass and Hogwallow Flats

To properly comprehend what’s going on with the bedrock from Jezero Crater, researchers will have to get their hands on them which is possible through NASA’s innovative Mars Sample Return mission. NASA intends to retrieve rock samples collected by Perseverance and return them to Earth for analysis. A sample of the Yori Pass sandstone would be a valuable prize. Katie Stack Morgan is a Jet Propulsion Laboratory (JPL by NASA) research scientist who is interested in Martian sedimentology, stratigraphy, and geologic mapping of planetary surfaces. Morgan compares the Yori Pass rock bed to Hogwallow Flats, popularly known as “the Bacon Strip” attributed to its light-coloured stripes stones since they are both situated at the very same altitude. They also have a massive, traceable footprint that is evident on the Martian surface. The rocks in Hogwallow Flats look to be particularly fine-grained. Fine-grained rocks are intriguing for mission scientists as they may have the best chance of preserving signs of life.

Conclusion

The Perseverance rover has been investigating the Jezero Crater since it landed on Mars in February 2021. For the first time, the rover’s spectacular fall was captured on video by the spacecraft. This spectacular Mars rover has gathered 14 rock-core samples and an air sample. Since then, these samples are kept in the rover’s belly. The sample-collection mission started in September 2021. First of all, it efficiently extracted a pencil-thin rock core from Jezero Crater. Then it was deposited in an airtight titanium sample tube. These materials are a significant part of the proposed joint NASA/ESA sample-return mission, which seeks to send a spacecraft to Mars. It will recover encased Martian rock and soil samples from Perseverance. Then they will be delivered to Earth for comprehensive and detailed in-depth investigation.

Bibliography

A Never-Seen-Before Exoplanet WASP-39b Atmosphere is Revealed by NASA’s Webb Space Telescope

by Rida Fatima

exoplanet WASP-39 b
(Figure 1: Based on what is known about the planet right now, this graphic depicts what the exoplanet WASP-39 b would look like. WASP-39 b is very hot, puffy full of gas that circulates just 0.0486 au (4,500,000 miles) from its star. It has a diameter that is 1.3 times larger than Jupiter and a mass that is 0.28 times Jupiter (or 0.94 times Saturn). WASP-39 is a star that is somewhat less massive and smaller than the Sun. WASP-39 b is extremely hot due to its near proximity to its star and is most likely tidally locked, with one side constantly facing the side of the star. Credits: www.nasa.gov)

A behemoth the size of Saturn that revolves around its star more closely than Mercury does the Sun, a planet known as WASP-39 b is unmatched by any other planets that exist in our solar system. This exoplanet was one of the first to be studied when NASA started the official science operations on a regular basis by using James Webb Space Telescope. The findings have the exoplanet scientific community in a frenzy. Moreover, potassium, carbon monoxide, Water, sodium, and sulphur dioxide have all been discovered in the profile of WASP-39 b’s atmospheric ingredients created by Webb’s highly sensitive detectors. The results are encouraging for Webb’s sensors’ capacity to carry out a wide range of studies of exoplanets of various types, including rocky, tiny planets that are considered in the TRAPPIST-1 system (Scitechdaily, 2022).

Signatures of molecule with active Chemistry and Clouds

The latest James Webb telescope mission by NASA was to discover the chemical and molecular profile of the skies of a distant world, marking another first. The latest results from Webb show a very comprehensive variety of molecules, atoms, and also some evidence of active chemistry and clouds, in contrast to earlier findings from space observatories, such as Spitzer and NASA’s Hubble. The most recent information also gives a suggestion as to how these clouds would seem up close, suggesting that they are likely split up rather than covering the globe uniformly. The array of the telescope’s highly delicate apparatus was focused right on the environment of WASP-39 b, circulating a star around 700 light-years distant. The results are promising for the ability of Webb’s apparatus to do the extensive range of analyses of all types of exoplanets, or worlds around other stars, that the scientific groups had hoped for. As part of this, it is possible to explore the atmospheres of smaller, stonier planets like those in the TRAPPIST-1 system. It has been noted that the telescope has a variety of equipment that, when combined, offer a wide range of infrared detection and a variety of chemical fingerprints that were previously out of reach. Data like these change the game of understanding these other planets (NASA, 2022).

Five new scientific publications, three of which are in under review and one of which is in press, cover the discoveries in depth. One of the ground-breaking discoveries is that of sulphur dioxide (SO2) for the first time in an exoplanet’s atmosphere. This molecule is the result of chemical processes started by high-energy light from the planet’s parent star. Similar processes are used on Earth to produce the protective ozone layer in the upper atmosphere.

Concrete evidence of photochemistry

The formation of Sulphur dioxide in WASP-39 b’s atmosphere was described in the paper by Shang-Min Tsai, a researcher at the University of Oxford in the United Kingdom. Tsai asserted that this was the first time actual proof of photochemistry—chemical processes initiated by energetic stellar light on exoplanets had been seen. I believe this effort has a highly promising future for enhancing our understanding of the atmospheres of exoplanets. Another first as a result of this was the use of photochemistry computer models on the data that assists with the full explanation of such physics. The ensuing advancements in modelling will contribute to the development of the technological know-how necessary to decipher future indications of habitability (NASA, 2022).

“We had anticipated what the telescope would reveal, but it was more accurate, more varied, and more stunning than I had truly anticipated” – Hanna Wakeford.

Planets circling within the host star’s radiation bath are molded and changed. These changes on Earth enable life to flourish. Eight times closer to its home star than Mercury is to our Sun, the planet serves as a testing ground for the effects of radiation from host stars on exoplanets. Improved comprehension of the star-planet relationship should lead to a greater comprehension of how these factors impact the variety of planets seen in the solar system. Webb followed WASP-39 b when it crossed in front of its star, allowing part of the star’s light to get through the planet’s atmosphere and allowing for the detection of light from the object. Astronomers can identify the molecules by looking at the colors that aren’t present because different kinds of particles in the atmosphere absorb different colors of the starlight range. Webb can identify chemical fingerprints in the universe that are invisible to the human eye by observing it in infrared light.

The Webb telescope also picked up measurements of sodium (Na), potassium (K), and water vapor (H2O), which confirmed earlier observations made by ground- and space-based telescopes and discovered new fingerprints of water at these longer wavelengths (NASA, 2022).

References

How NASA is planning to detect life on the Habitable Ocean Worlds of Europa and Enceladus

by Rida Fatima

Demonstration of the Icy under world of Enceladus
(Figure 1: Demonstration of the Icy under world of Enceladus showing the plumes emerging from beneath and going out in space. Credits: NASA/JPL (jpl.nasa.gov))

A team at the Lab has developed new innovative technologies that could be utilized by future space operations to analyze liquid samples from ocean worlds of Enceladus and Europa in search of alien life. Carl Sagan said, “Somewhere something incredible is waiting to be known”, enlightening a spark of curiosity to explore the unknown mysteries and riddles of the ever-expanding universe. One of the biggest questions of space exploration and search is “Are we alone in the Universe?” or do we have other interstellar or intergalactic companions living somewhere far away in the cosmos? NASA is playing an active role in this search and constantly developing innovative technologies for space investigations.

However, looking for signs of life in a frosty sea millions of miles away presents enormous challenges. The scientific equipment needed for this purpose must be intricately complex while also being resistant to intense radiation and cryogenic temperatures. Furthermore, the instruments must be capable of performing a variety of independent, complementary measurements that, when combined, may further yield scientifically rational proof of life (NASA, Europa Ocean Moon , 2022)

Ocean Worlds Life Surveyor (OWLS)

A device containing 8 instruments has been developed by NASA scientists that can detect life in watery geysers emerging from the icy moons such as Enceladus and possibly Europa. Saturn’s moon Enceladus and Jupiter’s moon Europa have always intrigued scientists as the prime location for the detection of life in the solar system. Due to thick ice, getting into these frosty ocean worlds is a difficult challenge. The Cassini spacecraft in 2006, discovered plumes of water vapor gushing from Enceladus. Likewise, the Hubble Space Telescope discovered intriguing evidence of geysers arising from Europa as well. A spacecraft upgraded with NASA’s new Ocean Worlds Life Surveyor (OWLS) device could now collect water samples while flying through the plumes. It will look for any microbial cells or bacterial sample evidence that the geysers may have ejected into space.

OWLS by NASA's JPL
(Figure 2: OWLS by NASA’s JPL incorporates powerful chemical-analysis instruments that look for life’s building blocks with microscopes that search for cells. This OWLS version would be miniaturized and customized for future missions. Credit: NASA/JPL-Caltech)

What Is So Unique About OWLS?

Cassini flyby across the plumes was indeed a significant approach, however, the spacecraft did not have this instrument installed in it. Therefore, it was not able to give us a clear picture of possibility of life residing in Enceladus. Due to the large distances between Earth and Jupiter and Saturn, frequency range for data transmission is limited. As a result, OWLS must collect massive amounts of data, independently analyze it in the hopes of discovering life. Then it will send only the relevant information back to Earth (Cooper, 2022)

OWLS is a complete package of 8 experiments capable of determining whether or not life exists in the specimens that it collects. Experiments with owls in California’s highly saline Mono Lake, which scientists believe is comparable to the salty sea waters of Europa and Enceladus’ oceans, successfully “discovered” life. OWLS is now prepared to confront the icy moons after some restructuring. The microscope system of OWLS could image cells as it is a group of various microscopes attached. It was created in collaboration with researchers at Portland State University in Oregon. A digital holographic microscope (DHM) that identifies cells and motion throughout the volume of a sample is combined with two fluorescent imagers, using dyes to analyze chemical content and cellular structures.

ELVIS and OCEANS

The Extant Life Volumetric Imaging System (ELVIS) is the microscope subsystem. It is unique in that it has no moving parts and it also employs machine-learning algorithms to detect objects illuminated by fluorescent molecules, regardless of whether naturally produced in living organisms or added dyes bound to cell parts (JPL, 2022).

ELVIS receives the liquid samples
(Figure 3: ELVIS receives the liquid samples while others will go under extraction process and are sent for chemical analysis. Credit: NASA/JPL (jpl.nasa.gov))

The DHM can be used in combination with the Organic Capillary Electrophoresis Analysis System (OCEANS) from OWLS. OCEANS is a technology for using electric potential to separate organic molecules in a liquid, such as amino acids, fatty acids, and nucleic acids. The molecules are then sent to a mass spectrometer. The masses of the particulate in the sample, and a volume fluorescence imager are measured. This imager binds these chemical building blocks together using dyes. When the compounds are excited by a laser, they emit photons and start to glow, providing an aim for the DHM to focus on.

Conclusion
After collecting a water sample, OWLS looks for evidence of life at the cellular and molecular level by integrating chemical analysis with high-resolution microscopy. Not only Europa and Enceladus, but all other ocean worlds like Titan, Ganymede, and Ceres are among the most likely candidates for life in our Solar System due to their watery and icy environments resembling to those found on Earth at various points in time. The Ocean Worlds Life Surveyor (OWLS) is the first life detection suite to investigate a broad range of size scales in a water sample, from single molecules to microscopic organisms. OWLS is a life-detection instrument suite that is incorporated, portable, and self-contained (NASA, n.d.).

Bibliography

  1. Cooper, K. (2022, November 01). NASA has a life-detecting instrument ready to fly to Europa or Enceladus . Retrieved from Space.com: https://www.space.com/life-detecting-instrument-ready-study-europa-enceladus
  2. JPL, N. (2022, Oct 06). JPL Developing More Tools to Help Search for Life in Deep Space. Retrieved from Jet Propulsion Laboratory: https://www.jpl.nasa.gov/news/jpl-developing-more-tools-to-help-search-for-life-in-deep-space
  3. NASA. (2022, August 15). Europa Ocean Moon . Retrieved from Solar System Exploration : https://solarsystem.nasa.gov/moons/jupiter-moons/europa/in-depth/
  4. NASA. (n.d.). Ocean Worlds Life Surveyor . Retrieved from Jet Propulsion Laboratory : https://www.jpl.nasa.gov/go/owls

The Mystery of Methuselah

by Rida Fatima

The oldest star in the universe is HD140283 — or Methuselah
Figure 1: The oldest star in the universe is HD140283 — or Methuselah as it’s commonly known. This Digitized Sky Survey image shows Methuselah star, located 190.1 light-years away. Astronomers refined the star’s age to about 14.3 billion years (which is older than the universe), plus or minus 800 million years. Image released March 7, 2013. (Image credit: Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech, and UKSTU/AAO)

Scientists tried to determine the age of what they believed to be the universe’s oldest star in 2000 and these observations were made with the help of the European Space Agency’s (ESA). HD140283, often known as Methuselah, was calculated by the Hipparcos satellite to be an astounding 16 billion years old. Such a number seemed somewhat perplexing. The universe is after all 13.8 billion years old, according to studies of the cosmic microwave background. Astronomers began seeking out the truth and vetting the figure’s correctness. Their findings were equally astounding (Crookes, 2022). Methuselah, named after a biblical patriarch who is claimed to have lived to the age of 969 and hence was the longest-living person in the Bible, has been the subject of astronomical observation for more than a century. Methuselah is about 190 light-years away from our planet, residing in the constellation Libra. It zips through the sky at an incredible 1.3 million kilometers per hour.

The metallically poor sub giant is primarily composed of hydrogen and helium, with very little iron which makes it obvious how old this star was (Crookes, 2022). Due to its chemical makeup, it must have formed before iron became widely distributed in the cosmos and during the helium and hydrogen era. However, is it possible that Methuselah is more than 2 billion years older than its surroundings? The cosmos was either not as “new” as scientists believed it to be, or Methuselah was older than the universe. Or maybe the dating was just completely off. What would it be?

Investigating the age of Methusela

This is a backyard view of the sky surrounding the ancient Methuselah star
Figure 2: This is a backyard view of the sky surrounding the ancient Methuselah star, cataloged as HD 140283. Image released March 7, 2013. (Image credit: A. Fujii and Z. Levay (STScI))

The Hubble Space Telescope had conducted observations, noting the locations, separations, and luminous output of stars. The scientists were able to establish a more accurate sense of age by the acquisition of parallax, spectroscopy, and photometry readings. The precise distance to the star was one of the unknowns associated with HD 140283’s age. It was crucial to get this right because it helps to calculate the star’s luminosity and, consequently, its age; the younger the star, the greater the intrinsic luminosity. The astronomers were looking for the parallax effect, which required them to observe the star twice, six months apart, in order to detect any change in the star’s location brought on by the Earth’s orbit, which may be used to determine the distance (Tang et al., 2021).

Astronomers also explain that the theoretical models of the stars also had uncertainties. This includes the exact rates of nuclear reactions in the core as well as the importance of elements being diffused downward in the external layers. As a result, they centered on the hypothesis that any residual helium diffuses deeper into the core, reducing the amount of hydrogen available for nuclear fusion. The age is decreased as fuel is utilized more quickly. The amount of oxygen present in the star was an additional essential component. Since oxygen was not abundant in the universe until a few million years ago, HD 140283 had an oxygen-to-iron ratio that was higher than expected, which again suggested a younger age for the star (Tang et al., 2021).

After doing all of this work, scientists determined that HD 140283 is 14.46 billion years old. Although it was far less than the previously stated age (16 billion), it was still significantly larger than the age of the universe. Within this regard, it still didn’t answer the question and, at first glance, seemed to do little more than ensure that Methuselah would remain a mystery (Lincoln, 2021). However, the scientists included an additional 800 million years of residual uncertainty. It was a significant development. The age of HD 140283 decreased slightly when more adjustments were made. In 2014, a follow-up study was done that reviewed the star’s age to 14.27 billion years. There is no conflict because 13.8 billion years falls inside the star’s error bar if one takes into account all sources of uncertainty, including those in observational measurements and theoretical models.

Additionally, in May 2021, a different team of astronomers updated the best hypotheses for the age and mass of Methuselah, and after modelling the evolution of stars, they determined that it is 12 billion years old. Even though the sun, at 4.6 billion years old, is still a baby compared to HD 140283, this nevertheless places the star’s age well within the universe’s age range. Or does it?

Why does the Universe appear younger than Methuselah

Artist's impression of the formation of the universe's first stars
Figure 3: Artist’s impression of the formation of the universe’s first stars. (Image credit: NASA/WMAP Science Team)

There are two possibilities explaining why universe appears younger than Methuselah. According to the scientific history, both possibilities may be true in such circumstances. In this situation, such would be unresolved sources of observational inaccuracy as well as some gaps in the dynamics of the universe theory. Primarily, this includes strength of dark energy, which has been the main force behind the cosmos’ long-term expansion (Bond et al., 2013).

Time variation in dark energy can explain the current “age paradox” leading to a change in the rate of acceleration. This hypothesis has been proven to be compatible with theories regarding the basic properties of gravity i.e., causal set theory. According to Matthews, fresh gravitational wave research may assist to explain the conundrum. Cosmic microwave background or the observation of nearby objects like Cepheid variables and supernovae will not be used to measure the Hubble Constant. However, scientists would instead look at the ripples created in the fabric of space and time by pairs of dead stars (Catelan, 2017).

Since gravitational waves were only directly discovered for the first time in 2015, detecting them is a difficult process. However, astronomer Stephen Feeney of the Flatiron Institute in New York believes that a discovery might be found within the next ten years. The goal is to gather information from pairs of neutron star collisions and measure their velocity in relation to Earth by measuring the visible light these events release. It also involves measuring the distance from the gravitational waves that are produced; when combined, these two factors can yield the most precise Hubble Constant determination ever.

The age of HD 140283 is a riddle that is leading to something bigger and more sophisticated in science. It is also changing our understanding of how the universe functions. The paradox is most likely explained by some empirical phenomenon that has gone unnoticed or by a significant gap in our knowledge of the dynamics of cosmic expansion. Astronomers will continue to face challenges as they try to determine exactly what that “something” is.

Reference

  • Crookes. (2022, March 7). Methuselah: The oldest star in the universe. Space.Com. https://www.space.com/how-can-a-star-be-older-than-the-universe.html
  • Tang, Jianling, and Meridith Joyce. “Revised Best Estimates for the Age and Mass of the Methuselah Star HD 140283 Using MESA and Interferometry and Implications for 1D Convection.” Research Notes of the AAS 5.5 (2021): 117.
  • Lincoln, Don. “Have Astronomers Found a Star Older Than the Universe?.” The Physics Teacher 59.3 (2021): 154-158.
  • Bond, Howard E., et al. “HD 140283: A star in the solar neighborhood that formed shortly after the Big Bang.” The Astrophysical Journal Letters 765.1 (2013): L12.
  • Catelan, M. “The ages of (the oldest) stars.” Proceedings of the International Astronomical Union 13.S334 (2017): 11-20.