A Young Exoplanet's Atmosphere Doesn't Match its Birthplace

If the modern age of astronomy could be summarized in a few words, it would probably be “the age of shifting paradigms.” Thanks to next-generation telescopes, instruments, and machine learning, astronomers are conducting deeper investigations into cosmological mysteries, making discoveries, and shattering preconceived notions. This includes how systems of planets form around new stars, which scientists have traditionally explained using the Nebular Hypothesis. This theory states that star systems form from clouds of gas and dust (nebulae) that experience gravitational collapse, creating a new star.

The remaining gas and dust then settle into a protoplanetary disk around the new star, which gradually coalesces to create planets. Naturally, astronomers theorize that the composition of the planets would match that of the disk itself. However, when examining a still-developing exoplanet in a distant star system, a team of astronomers uncovered a mismatch between the gases in the planet’s atmosphere and those within the disk. These findings indicate that the relationship between a protoplanetary disk and the planets they form might be more complicated.

The team was led by Postdoctoral Associate Chih-Chun “Dino” Hsu from the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University. He and his colleagues were joined by researchers from the California Institute of Technology (Caltech), the University of California San Diego (UCSD), and the University of California Los Angeles (UCLA). The paper that details their findings, “PDS 70b Shows Stellar-like Carbon-to-oxygen Ratio,” recently appeared in The Astrophysical Journal Letters.

The W.M. Keck Observatory at the summit of Mauna Kea, Hawaii. Credit: MKO

For their study, the team relied on the Keck Planet Imager and Characterizer (KPIC), a new instrument at the W.M. Keck Observatory, to obtain spectra from PDS 70b. This still-forming exoplanet orbits a young variable star (only ~5 million years old) located about 366 light-years from Earth. It is the only one known to astronomers with protoplanets residing in the cavity of the circumstellar disk from which they formed, making it ideal for studying exoplanet formation and evolution in their natal environment. Jason Wang, an assistant professor of physics and astronomy at Northwestern who advised Hsu, explained in a Northwestern News press release:

“This is a system where we see both planets still forming as well as the materials from which they formed. Previous studies have analyzed this disk of gas to understand its composition. For the first time, we were able to measure the composition of the still-forming planet itself and see how similar the materials are in the planet compared to the materials in the disk.”

Until recently, astronomers were unable to study a protoplanetary disk directly to track the birth of new planets. By the time most exoplanets are observable to telescopes, they have finished forming, and their natal disks have since disappeared. These observations are historic in that this is the first time scientists have compared information from an exoplanet, its natal disk, and its host star. Their work was made possible by new photonics technologies co-developed by Wang for the Keck telescopes.

This technology allowed Hsu and his team to capture the spectra of PDS 70b and the faint features of this young planetary system, despite the presence of a much brighter star. “These new tools make it possible to take really detailed spectra of faint objects next to really bright objects,” said Wang. “Because the challenge here is there’s a really faint planet next to a really bright star. It’s hard to isolate the light of the planet in order to analyze its atmosphere.”

The resulting spectra revealed the presence of carbon monoxide and water in PDS 70b’s atmosphere. This allowed the team to calculate the inferred ratio of atmospheric carbon and oxygen, which they compared to previously reported measurements of gases in the disk. “We initially expected the carbon-to-oxygen ratio in the planet might be similar to the disk,” said Hsu. “But, instead, we found the carbon, relative to oxygen, in the planet was much lower than the ratio in the disk. That was a bit surprising, and it shows that our widely accepted picture of planet formation was too simplified.”

Artist‘s depiction of a protoplanetary disk in which planets are forming. Credit: ESO/L. Calçada

To explain this discrepancy, the team proposed two possible explanations. These include the possibility that the planet might have formed before its disk became enriched in carbon or that the planet might have grown mostly by absorbing large amounts of solid materials in addition to gases. While the spectra show only gases, the team acknowledges that some of the carbon and oxygen could have accreted from solids trapped in ice and dust. Said Hsu:

“For observational astrophysicists, one widely accepted picture of planet formation was likely too simplified. According to that simplified picture, the ratio of carbon and oxygen gases in a planet’s atmosphere should match the ratio of carbon and oxygen gases in its natal disk — assuming the planet accretes materials through gases in its disk. Instead, we found a planet with a carbon and oxygen ratio that is much lower compared to its disk. Now, we can confirm suspicions that the picture of planet formation was too simplified.”

“If the planet preferentially absorbed ice and dust, then that ice and dust would have evaporated before going into the planet,” added Wang. “So, it might be telling us that we can’t just compare gas versus gas. The solid components might be making a big difference in the carbon-to-oxygen ratio.” To explore these theories further, the team plans to obtain spectra from the other PDS 70c, the other fledging exoplanet in the system. “By studying these two planets together, we can understand the system’s formation history even better,” Hsu said. “But, also, this is just one system. Ideally, we need to identify more of them to better understand how planets form.”

Further Reading: Northwestern Now, The Astrophysical Journal Letters

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Hotter White Dwarfs Get Puffier

When our Sun dies, it will turn into a white dwarf. They are a common aspect of stellar evolution and a team of researchers have now turned their attention onto them. They have just completed a survey of 26,000 white dwarfs and confirmed a long-predicted theory that the hotter the star, the puffier it is! This new study will help us to understand white dwarfs and the processes that drive them. 

All stars age. Our Sun is a giant ball of electrically charged gas and, during the majority of its life will be fusing hydrogen to helium in its core. During this process, the fusion will generate an outward pushing force known as thermonuclear pressure which will for the most part, balance the inward pull of gravity. Eventually, the thermonuclear force will overcome the force of gravity and the star will shed its outer layers, leaving behind a dense, hot core. The core is known as a white dwarf and it is this which, despite its small size and incredibly high density, has captivated astronomers. 

The solar surface in visible light composed of data from Solar Orbiter’s instrument PHI from March 22, 2023

One of the more fascinating aspects of white dwarf stars is their relationship between temperature and density. Theory suggests that the hotter a white dwarf star becomes, the less dense and more puffy its outer layers become. The lower density is thought to be driven by an increase in energy pushing outward which comes from an increased core temperature. Typically the core of a white dwarf can reach between 5,000 to 10,000 Kelvin. 

This artist’s impression shows the magnetic white dwarf WD 0816-310. Credit: ESO/L. Calçada

The team of astronomers led by Nicole Crumpler from the John Hopkins University published the results of their findings in the Astrophysical Journal. They hope that their work will take us a step closer to being able to exploit white dwarfs as natural stellar laboratories to unravel the mysteries of dark matter! The secret, the team believe, is in the puffy nature of white dwarfs. “If you want to look for dark matter, quantum gravity, or other exotic things, you better understand normal physics,” said Crumpler, “otherwise, something that seems novel might be just a new manifestation of an effect that we already know.”

At its core is the fact that these stellar corpses are composed of material far heavier than normal matter.  A teaspoon of their material weighs around a ton, clearly far more than ordinary matter. With all that mass packed so tightly into the small stellar corpse, the gravitational pull is far higher than here on Earth. 

The study focussed on measuring how these high material densities influence light waves travelling away from the star. The waves will lose energy, stretching the radiation and ‘red-shifting’ it so telescopes can measure it. By averaging the measurements of white dwarf stars and their motions relative to Earth, the team were able to isolate the redshift from the affect of gravity to calculate how high the temperatures are and therefore influence the gas density in outer layers. 

Artist impression of ESA’s Gaia satellite observing the Milky Way (Credit : ESA/ATG medialab; Milky Way: ESA/Gaia/DPAC)

To conclude their study, the team used data from the Solan Digital Sky Survey and the ESA Gaia mission. Together these observation programs have recorded positions of millions of stellar objects. By studying tens of thousands of white dwarfs the team hope that probing the nature of the matter will help to understand more about its nature, about the nature of dark matter and the nature of the structure of the white dwarf stars that pervade our Galaxy. 

Source : Survey of 26,000 dead stars confirms key details of extreme stellar behavior

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NASA to Probe the Secrets of the Lunar Regolith

Gaze up at the Moon on any night and you will see a barren world displaying all manner of shades of grey. Aside from the obvious craters and lunar maria, the surface of the Moon is covered in the fine, dusty lunar regolith. The Apollo astronauts in the 60’s and 70’s learned that it was electromagnetically charged and was very abrasive posing a problem for mechanical equipment. Now a new payload on the Commercial Lunar Payload Services initiative will explore the regolith even further. 

The Moon is our only natural satellite. It has a diameter of 3,474 kilometres and is about a quarter the size of the Earth. Orbiting Earth at a distance of 384,400 kilometres, the Moon is our closest neighbour and has inspired artists, authors and scientists alike. From Earth we can only see half of the Moon, the near side due to a phenomenon known as captured or synchronus rotation. The countless craters are the result of meteorite strikes ont eh lunar surface and the darker, larger lunar maria are vast plains of darker solidified lava. As experienced by the Apollo astronauts, the surface is covered in a fine powdery material known as the lunar regolith.

The Moon on August 24, 2023, with the eQuinox 2 telescope by Unistellar. Credit: Nancy Atkinson.

The lunar regolith is the loose, dusty layer of material that covers the solid bedrock of the surface of the Moon. It’s made up of tiny fragments which have been created from the pulverisation of lunar rocks over billions of years by meteoric impacts. It’s mostly composed of minerals like silicates, feldspar and pyroxenes and small quantities of metals too. Whilst it can pose a real challenge to lunar explorers due to its abrasive nature it can also be used to produce oxygen and water and can be a fabulous material for construction of lunar habitats. 

A close-up view of astronaut Buzz Aldrin’s bootprint in the lunar soil, photographed with the 70mm lunar surface camera during Apollo 11’s sojourn on the moon. There’ll soon be more boots on the lunar ground, and the astronauts wearing those boots need a way to manage the Moon’s low gravity and its health effects. Image by NASA

Understanding the nature of the lunar regolith is the task of a new science instrument called RAC-1 (Regolith Adherence Characterisation) that will be heading toward the Moon as part of the Commercial Lunar Payload Services (CLPS) initiative. It will be transported to the lunar surface by the Blue Ghost 1 Lunar Lander. CLPS is a program setup by NASA to aid the development of lunar exploration by bringing companies together and taking their payloads to the Moon. It aims to support the Artemis program by providing innovation to space exploration and to help understand more about the lunar environment. 

NASA has selected three commercial Moon landing service providers that will deliver science and technology payloads under Commercial Lunar Payload Services (CLPS) as part of the Artemis program. Each commercial lander will carry NASA-provided payloads that will conduct science investigations and demonstrate advanced technologies on the lunar surface, paving the way for NASA astronauts to land on the lunar surface by 2024…The selections are:..• Astrobotic of Pittsburgh has been awarded $79.5 million and has proposed to fly as many as 14 payloads to Lacus Mortis, a large crater on the near side of the Moon, by July 2021…• Intuitive Machines of Houston has been awarded $77 million. The company has proposed to fly as many as five payloads to Oceanus Procellarum, a scientifically intriguing dark spot on the Moon, by July 2021…• Orbit Beyond of Edison, New Jersey, has been awarded $97 million and has proposed to fly as many as four payloads to Mare Imbrium, a lava plain in one of the Moon’s craters, by September 2020. ..All three of the lander models were on display for the announcement of the companies selected to provide the first lunar landers for the Artemis program, on Friday, May 31, 2019, at NASA’s Goddard Space Flight Center in Greenbelt, Md. ..Read more: https://ift.tt/iSfg4sV: NASA/Goddard/Rebecca Roth

RAC-1 will study the lunar regolith on arrival at the lunar surface. It was developed by Aegis Aerospace from Texas, a company that specialises in space systems engineering, technology development and mission support services. The device will explore how the lunar regolith adheres and sticks to certain surfaces to help understand how it can damage and interfere with mechanical and scientific instruments. This will help understand factors such as electrostatic attraction, abrasive and adherence forces. The low gravity of the Moon and lack of atmosphere will have an impact on how the dust behaves to help understand long term exposure to the harsh lunar environment. 

It works by exposing 15 sample materials to the regolith. These include fabrics, paint coatings, optical sensors, solar cells and more. It will measure rates of accumulation during the landing phase and other segments of the mission to learn which materials are best at repelling or shedding collected dust. Future missions like the Artemis program will greatly benefit from these studies. 

Source : NASA Science Payload to Study Sticky Lunar Dust Challenge

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NOIRLab Launches Collection of Hi-Res Images of 88 IAU-recognized Constellations

Located in Tuscon, Arizona, the National Optical-Infrared Astronomy Research Laboratory (NOIRLab) is a national facility consisting of four observatories that provide astronomers affiliated with any US institution with access to observing time. As part of its mission to advance astronomy and science education, NOIRLab recently announced the release of the 88 Constellations Project, a collection of free, high-resolution, downloadable images of all IAU-recognized constellations. This project is an educational archive that is free for all and includes the largest open-source all-sky photo of the night sky.

The high-quality images behind this collection were taken by German astrophotographer Eckhard Slawik (whose portfolio can be found here). The images were taken on film, and each panel consists of two separate exposures, with and without a diffuser filter, to emphasize the stars’ colors. The collection is arranged alphabetically, from Andromeda to Vulpecula, and includes information on the historic origins of each constellation, their brightest stars, their stick-figure diagram, how to find them, and prominent deep-sky objects within them.

Photo of the constellation Andromeda with annotations from IAU and Sky & Telescope. Credit: E. Slawik/NOIRLab/NSF/AURA/M. Zamani

Images of these deep-sky objects, captured by telescopes at NOIRLab’s four participating observatories, are also provided. These include distant galaxies, star clusters, nebulae, black holes, and other notable astronomical objects. The collection also includes educational resources for teachers, like flashcards and audiovisual resources that can be used at the primary and secondary levels. NOIRLab also recommends the 88 Constellations project be used as a resource in planetariums and museums.

The all-sky photo, also the work of Slawik, was created using images taken from the darkest locations around the world. At 40,000 pixels, it is arguably one of the most detailed and beautiful images of the night sky ever made. The full collection can be found on the NOIRLab project webpage.

Further Reading: NOIRLab

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Saturn’s Rings Might Be Really Old After All

Saturn’s rings are among the most glorious, stunning, and well-studied features in the Solar System. However, their age has been difficult to ascertain. Did they form billions of years ago when the planet and the Solar System were young? Or did they form in the last few hundred millions of years?

The latest new research shows that the iconic rings are, in fact, very old.

We first became aware of Saturn’s opulent rings hundreds of years ago. Galileo was the first to see them, though he couldn’t tell they were rings in his early telescope. Nobody had ever seen anything like them before, obviously, and he thought they were moons. When he observed the planet two years later, the ‘moons’ had disappeared, leaving him confused. Another two years passed, and when he observed Saturn again, they had returned. However, the viewing angle had changed, and what he once thought were moons he concluded were ‘arms’ of some sort.

Top: Galileo’s sketch of Saturn from 1610. Bottom: Galileo’s sketch of Saturn from 1616. Image Credit: Galileo Galilei. ;<)

Decades later, Christian Huygens had a much better telescope and deduced that the features were actually rings. He described them as a “thin, flat ring, nowhere touching the planet, inclined to the ecliptic plane, and surrounding the planet without touching it.”

Fast forward to our modern age of space exploration, and scientists have gotten much better looks at Saturn and its rings. Voyager 1 and Voyager 2 opened our eyes to Saturn’s unique rings when they flew past the planet in 1980 and 1981. Those images began to reveal some of the rings’ complexity, including unusual ‘spoke’ shapes. The mystery deepened.

This Voyager 2 image from August 1981 shows the unusual dark, spoke shapes in the rings. Image Credit: NASA/JPL-Caltech

When the Hubble Space Telescope launched, it brought Saturn’s rings to life with its stunning images. It confirmed that the rings aren’t uniform and contain many fainter inner rings and ringlets. It also found that icy particles from the rings rain down on Saturn and help heat its atmosphere.

However, the Cassini spacecraft has revealed the most about Saturn’s rings. It spent 13 years investigating Saturn, its moons, and its rings.

Cassini’s data has transformed our understanding of the gas giant. No longer were scientists restricted to telescope images or fleeting flybys from the Voyager spacecraft. Cassini captured unprecedented close-up views of Saturn and its rings and gathered detailed measurements.

This is the highest-resolution image ever captured of Saturn’s rings. It shows part of the B ring. The different ringlets are part of the B-ring’s irregular structure. Cassini captured this image in July 2017. Image Credit: NASA/JPL-Caltech/Space Science Institute

Cassini revealed the complex dynamics at play in the rings and intricate details, including kinks and clumps. It showed us how the rings change over time due to Saturn’s gravity and all of its moons and moonlets. One of its biggest discoveries is that the rings are largely composed of water ice.

However, scientists are still uncertain exactly how old the rings are. Different researchers come up with different results. Some say they’re billions of years old, while others say they’re as young as 100 million years old.

New research in Nature Geoscience suggests that the rings cannot be only a few hundred million years old. It’s titled “Pollution resistance of Saturn’s ring particles during micrometeoroid impact.” The lead author is Ryuki Hyodo, a planetary scientist associated with JAXA and several universities and space agencies.

The young estimates for Saturn’s rings’ ages stem from their colouration. They appear to be clean despite their expected bombardment by micrometeoroids. The models that arrived at youthful estimates were based on high accretion rates for micrometeoroids. The logic says that if micrometeoroids bombard the ring particles and accrete efficiently, the rings should be much darker than they appear to be. Hence, they must be young. Estimates based on this arrive at an age of between 100 and 400 million years for Saturn rings.

However, those models are based on highly efficient accretion rates for micrometeoroids onto icy particles in the rings.

In the new research, Hyodo and his fellow researchers simulated the hypervelocity impacts of micrometeoroids striking icy particles. They found that the accretion may not be as efficient as previous research suggested. Instead, the non-icy micrometeorites can be vaporized, expand, and then form charged particles and ions.

These particles then leave the ring system via three main processes. They either collide with Saturn, leave the planet’s gravitational field, or are dragged into Saturn’s atmosphere electromagnetically.

This figure from the research summarizes the simulation results. a) Micrometeoroid impacts on Saturn’s rings occur at impact velocities of ~30 km?s–1. b) The impactor materials are highly shocked (>100?GPa) and form hot expanding vapour (>10,000?K). Only a small fraction of the ring particles (mass comparable to the impactor) is vaporized. c) The impact-generated vapour expands with a high velocity (on average >14?km?s–1), producing atoms/molecules and forming nanoparticles as condensates. The silicate vapour is more prone to condensation than water vapour. d) Atoms or molecules are ionized, nanoparticles are charged in Saturn’s magnetosphere, and impactor materials are removed from the ring plane by direct collision with Saturn, by escape from Saturn’s gravitational field, or by being dragged into Saturn by interaction with the electromagnetic field. Image Credit: Hyodo et al. 2024. Credit: d, NASA Goddard Space Flight Center.

The critical part of the study and how it differs from previous efforts is in the accretion efficiency of micrometeorites. Previous models used an accretion efficiency of greater than or equal to 10%. However, this study shows that the actual accretion efficiency might be much lower, greater than or equal to only 1%. That means that the rings could be much older and only appear to be clean because micrometeoroids don’t accrete as efficiently as thought and don’t ‘dirty’ the appearance of the rings.

“Thus, we suggest that the apparent youth of Saturn’s rings could be due to pollution resistance rather than indicative of young formation age,” the authors write.

This won’t be the last word on Saturn’s rings and their ages. All models have limitations, and Hyodo and his co-researchers acknowledge some limitations in theirs. Their model doesn’t account for porosity, strength, or the granularity of the ring particles.

Still, the study emphasizes that dynamic forces are at play that need to be considered in the evolution of planetary bodies and that some of our long-held assumptions need to be questioned.

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Covering an Asteroid With Balls Could Characterize Its Interior

Exploring asteroids and other small bodies throughout the solar system has gotten increasingly popular, as their small gravity wells make them ideal candidates for resource extraction, enabling the expansion of life into the solar system. However, the technical challenges facing a mission to explore one are fraught – since they’re so small and variable, understanding how to land on one is even more so. A team from the University of Trieste in Italy has proposed a mission idea that could help solve that problem by using an ability most humans have but never think about.

Have you ever closed your eyes and tried to touch your fingers to one another? If you haven’t, try it now, and you’ll likely find that you can easily. It’s possible to do even without guidance from your five normal senses. That is what is known as proprioception – our hidden “sixth” sense. It is that ability to know where objects are in relation to one another – in this case, where your hands are in relation to one another without any other sensory indication.

Taking that basic idea and extrapolating it to a mission to an asteroid, the basic concept of the mission involves a lander with what seems like a dome with a ton of little balls on it, each facing a slightly different direction. Those balls are then ejected from the dome with varying degrees of force and land on various parts of the asteroid or comet.

Fraser discusses why swarms are becoming so central to our idea of space exploration.

They then create what is known in networking as a “mesh” system by connecting through one another and back to the main lander, which has a higher power output and larger communications array. They also contain a series of sensors, such as a camera, a magnetometer, and, importantly, an inertial measurement unit, or IMU.

IMUs are commonly used in cell phones to tell which direction the phone is oriented—that’s why your phone’s screen will flip upside down if you hold it upside down. They can also measure acceleration, which is why many are used in modern rocketry. They’re tiny and not very power-hungry, allowing them to fit into the ball format used for this mission.

Measurements from each of the remote sensors IMUs can be combined with data about the strength of the force that propelled them to their final resting place and fed into an algorithm, which will then help the base station determine the location of each sensor unit. That then allows measurements from the other sensors, such as the magnetometers and cameras, to paint a picture of the body’s external and internal structure – since magnetic fields, surface objects, and even gravity can vary significantly on small celestial bodies.

There are plenty of missions using swarms to explore asteroids – like the MIDEA project, as described here.
Credit – Cosmic Voyages YouTube Channel

As a proof of concept for this mission design, the team ran a simulation of a mission to comet 67P/Churyumov-Gerasimenko, most widely known for being visited by Rosetta, the ESA mission whose lander, Philae, experienced some of the trouble that is so common on these missions. They found that, depending on the number of projectile sensors, the mission could cover even weird morphologies like 67P/Churyumov-Gerasimenko’s two-lobed form. 

No agency has yet taken up the mission, but as electronics and sensors get smaller and more power efficient and more small bodies become potential resource sources, there might be a place for testing these spaced-out sensors. We’ll have to wait and see—just not with proprioception alone.

Learn More:
Cottiga et al. – Proprioceptive swarms for celestial body exploration
UT – Could You Find What A Lunar Crater Is Made Of By Shooting It?
UT – Swarming Satellites Could Autonomously Characterize an Asteroid
UT – Swarms of Orbiting Sensors Could Map An Asteroid’s Surface

Lead Image:
Depiction of the mission’s lander and deployable sensor system.
Credit – Cottiga et al.

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New Image Revealed by NASA of their New Martian Helicopter.

Ingenuity became the first aircraft to fly on another world in the first half of 2021. It explored the Martian terrain from above proving that powered air flight was a very efficient way to move around alien worlds. Now NASA have released a computer rendering of their next design, the Mars Chopper! 

Ingenuity was a small helicopter, or rather more a drone, that was carried to Mars on board the Perseverance rover mission in 2020. It was designed as a technology demonstration to prove that powered flight was possible in the thin atmosphere of Mars. It made its first flight on 19 April 2021 and hovered just 10 feet above the ground before safely landing again. Since then, Ingenuity has completed 60 flights on Mars helping to survey and scout for areas of interest for further study. 

This view of NASA’s Ingenuity Mars Helicopter was generated using data collected by the Mastcam-Z instrument aboard the agency’s Perseverance Mars rover on Aug. 2, 2023, the 871st Martian day, or sol, of the mission, one day before the rotorcraft’s 54th flight. Credit: NASA/JPL-Caltech/ASU/MSSS

Operating a drone in the Martian atmosphere offers challenges largely due to the lower density. Compared to Earth, the atmosphere is less than 1% the density of Earth’s atmosphere. This means the blades on any aerial vehicles need to work harder and generate more lift than their Earth-bound counterparts. 

Image of the Martian atmosphere and surface obtained by the Viking 1 orbiter in June 1976. (Credit: NASA/Viking 1)

Density aside, the fine dust on the surface of Mars is often lifted up into the atmosphere which could damage the delicate mechanisms of operating craft. Not only must these types of vehicles be carefully designed to fly in alien atmospheres but they must also be able to protect themselves from local hazards. 

Moving on from the success of the Ingeniuty drone, NASA has released a rendering of its next generation vehicle for aerial flight on Mars, known as the Mars Chopper. Ingenuity was a feasability study and proved aerial flight successful, new craft on the drawing board come with a greater payload capacity to carry scientific instruments such as imaging and analysis kit. This will enable them to undertake the basic tasks like scouting activity to support future exploration but also undertake analysis and terrain mapping work. Ultimately even providing support to the human exploration of Mars.

The image released reveals a drone like vehicle which is about the size of an SUV with six rotors.  Each rotor has six blades which are smaller than those on Ingenuity but collectivity can provide even more lift. The payload capacity of the Chopper in its current design configuration is 5 kilograms a distance of up to 3km. The design is a collaboration between the Jet Propulsion Laboratory in Southern California and the Ames Research Center. 

This new model will be a real game changer for the exploration not only of Mars but of any alien worlds with a solid surface and an atmosphere that can support flight. Ingenuity led the way proving the technology and now, with the new concept Mars ‘Choppers on the drawing board, aerial reconnaissance on these new worlds will vastly improve the value of ground based exploration. Remote aerial exploration will also be of invaluable benefit to support human exploration where rovers will be unable to reach. 

Source : NASA’s Mars Chopper Concept (Rendering)

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NASA’s Parker Solar Probe Makes its Record-Breaking Closest Approach to the Sun

In August 2018, NASA’s Parker Solar Probe (PSP) began its long journey to study the Sun’s outer corona. After several gravity-assist maneuvers with Venus, the probe broke Helios 2‘s distance record and became the closest object to the Sun on October 29th, 2018. Since then, the Parker probe’s highly elliptical orbit has allowed it to pass through the Sun’s corona several times (“touch the Sun”). On December 24th, 2024, NASA confirmed that their probe made its closest approach to the Sun, passing just 6 million km (3.8 million mi) above the surface – roughly 0.04 times the distance between the Sun and Earth (0.04 AU).

In addition to breaking its previous distance record, the PSP passed through the solar atmosphere at a velocity of about 692,000 km/h (430,000 mph). This is equivalent to about 0.064% the speed of light, making the Parker Solar Probe the fastest human-made object ever. After the spacecraft made its latest pass, it sent a beacon tone to confirm that it made it through safely and was operating normally – which was received on December 26th. These close passes allow the PSP to conduct science operations that will expand our knowledge of the origin and evolution of solar wind.

Every flyby the probe made with Venus in the past six years brought it closer to the Sun in its elliptical orbit. As of November 6th, 2024, the spacecraft reached an optimal orbit that brings it close enough to study the Sun and the processes that influence space weather but not so close that the Sun’s heat and radiation will damage it. To ensure the spacecraft can withstand temperatures in the corona, the Parker probe relies on a carbon foam shield that can withstand temperatures between 980 and 1425 °C (1,800 and 2,600 degrees °F).

This shield also keeps the spacecraft instruments shaded and at room temperature to ensure they can operate in the solar atmosphere. Said Associate Administrator Nicky Fox, who leads the Science Mission Directorate (SMD) at NASA Headquarters in Washington, in a recent NASA press release:

“Flying this close to the Sun is a historic moment in humanity’s first mission to a star. By studying the Sun up close, we can better understand its impacts throughout our solar system, including on the technology we use daily on Earth and in space, as well as learn about the workings of stars across the universe to aid in our search for habitable worlds beyond our home planet.”

Nour Rawafi, the project scientist for the Parker Solar Probe at the Johns Hopkins Applied Physics Laboratory (JHUAPL), is part of the team that designed, built, and operates the spacecraft. “[The] Parker Solar Probe is braving one of the most extreme environments in space and exceeding all expectations,” he said. “This mission is ushering a new golden era of space exploration, bringing us closer than ever to unlocking the Sun’s deepest and most enduring mysteries.”

The Parker Solar Probe was first proposed in a 1958 report by the National Academy of Sciences’ Space Science Board, which recommended “a solar probe to pass inside the orbit of Mercury to study the particles and fields in the vicinity of the Sun.” While the concept was proposed again in the 1970s and 1980s, it would take several more decades for the technology and a cost-effective mission to be realized.

The Parker Solar Probe also made several interesting and unexpected finds during previous close passes. During its first pass into the solar atmosphere in 2021, the spacecraft discovered that the outer boundary of the corona is characterized by spikes and valleys, contrary to expectations. It also discovered the origin of switchbacks (zig-zag structures) in the solar wind within the photosphere. Since then, the spacecraft has spent more time in the corona, closely examining most of the Sun’s critical processes.

NASA’s Parker Solar Probe survived its record-breaking closest approach to the solar surface on December 24th, 2024. Credits: NASA

The probe’s discoveries are not limited to the Sun either. As noted, one of the PSP’s primary objectives is to study how solar activity influences “space weather,” referring to the interaction of solar wind with the planets of the Solar System. For instance, the probe has captured multiple images of Venus during its many gravity assists, documented the planet’s radio emissions, and the first complete image of Venus’ orbital dust ring. The probe has also been repeatedly blasted by coronal mass ejections (CMEs) that swept up dust as they passed through the Solar System.

“We now understand the solar wind and its acceleration away from the Sun,” said Adam Szabo, the Parker Solar Probe mission scientist at NASA’s Goddard Space Flight Center. “This close approach will give us more data to understand how it’s accelerated closer in.”

The probe even offered a new perspective on the comet NEOWISE by capturing images from its unique vantage point. Now that the mission team knows the probe is safe, they are waiting for it to reach a location where it can transmit the data collected from its latest solar pass. “The data that will come down from the spacecraft will be fresh information about a place that we, as humanity, have never been,” said Joe Westlake, the director of the Heliophysics Division at NASA Headquarters. “It’s an amazing accomplishment.”

The spacecraft’s next solar passes are planned for March 22nd, 2025, and June 19th, 2025.

Further Reading: NASA

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Meteor Showers May One Day Help Protect Humanity!

For centuries, comets have captured our imagination. Across history they have been the harbingers of doom, inspired artists and fascinated astronomers. These icy remnants of the formation of the Solar System hold secrets to help us understand the events nearly 5 billion years ago. But before these secrets can be revealed, comets have to be studied and to study them they need to be found. A team of researchers have developed a technique to hunt down comets based upon data from meteor showers and to asses if they pose any threat to us here on Earth!

Comets are objects that orbit the Sun like the planets but their orbits are usually more elliptical. They are composed of dust, gas and water ice and often called ‘dirty snowballs.’ Many comets are part of, or were a part of the Oort Cloud or Kuiper Belt. These distant regions of space house many of the Solar System’s icy bodies. On occasions, interactions between the bodies in the clouds can send chunks in toward the inner Solar System transforming the dormant chunks of rock and ice into the comets we recognise. Driven by heating from the Sun, the ice immediately sublimates into a gas giving rise to a comets familiar fuzzy coma and tail. Contrary to popular belief, the tail of a comet doesn’t stream out behind the comet as it travels through space, instead, it always points away from the Sun pushed in that direction by the Solar Wind. 

Geysers of dust and gas shooting off the comet’s nucleus are called jets. The volatile material they deliver outside the nucleus builds the comet’s coma. Credit: ESA/Rostta/NAVCAM

Comets are categorised as either short period comets or long period with the latter group having an orbit of more than 200 years. Due to their long orbits, scientists fear that one  will be on a collision course with Earth and go completely un-noticed until it is too late.  The risk of this occurrence is of course incredibly small but the impact could be catastrophic to life on Earth. A team of astronomers led by Samantha Hemmelgarn from the Northern Arizona University has published a paper in Planetary Science Journal where they explain their technique for identifying threats from long period comets using  data from meteor showers. 

Leonids meteor shower

“This research gets us closer to defending Earth because it gives us a model to guide searches for these potentially hazardous objects,” Hemmelgarn said. Meteor showers occur when the Earth passes through the debris left behind by a comet. The team has studied 17 meteor showers that are associated with long period comets and calculated where the parent comet should be in space.

Using the path of the meteor showers, the team can assess the liklihood that a long period comet could pose a threat over its future orbits. In the test cases, the model accurately predicted the comet locations including its direction and speed of travel. This provides the opportunity for astronomers to hone their search around the sky looking for long period comets rather than hope one might be spotted through automated searchers that scour the whole sky. 

The obvious benefit is that early identification of a comet on a collision course with Earth means that there is more time to develop a plan for our defence. There is nothing yet that provides any concern for astronomers but the next impact event of extinction level, may be millions of years away. The team hope that their work and model will help to provide humanity with the earliest warning of potential impacts. 

Source : How to Find a Comet Before it Hits Earth

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NASA is Considering Designs and Simulations to Prepare Astronauts for Lighting Conditions Around the Lunar South Pole

In the coming years, NASA and other space agencies will send humans back to the Moon for the first time since the Apollo Era—this time to stay! To maximize line-of-sight communication with Earth, solar visibility, and access to water ice, NASA, the ESA, and China have selected the Lunar South Pole (LSP) as the location for their future lunar bases. This will necessitate the creation of permanent infrastructure on the Moon and require that astronauts have the right equipment and training to deal with conditions around the lunar south pole.

This includes lighting conditions, which present a major challenge for science operations and extravehicular activity (EVA). Around the LSP, day and night last for two weeks at a time, and the Sun never rises more than a few degrees above the horizon. This creates harsh lighting conditions very different from what the Apollo astronauts or any previous mission have experienced. To address this, the NASA Engineering and Safety Council (NESC) has recommended developing a wide variety of physical and virtual techniques that can simulate the visual experiences of Artemis astronauts.

In the past, the design of lighting and functional vision support systems has typically been relegated to the lowest level of program planning. This worked well for the Apollo missions and EVAs in Low Earth Orbit (LEO) since helmet design alone addressed all vision challenges. Things will be different for the Artemis Program since astronauts will not be able to avoid having harsh sunlight in their eyes during much of the time they spend doing EVAs. There is also the challenge of the extensive shadowing around the LSP due to its cratered and uneven nature, not to mention the extended lunar nights.

Artist’s rendering of the Starship HLS on the Moon’s surface. NASA has contracted with SpaceX to provide the lunar landing system. Credit: SpaceX

In addition, astronaut vehicles and habitats will require artificial lighting throughout missions, which means astronauts will have to transition from ambient lighting to harsh sunlight and/or intense darkness and back. Since the human eye has difficulty adapting to these transitions, it will impede an astronaut’s “function vision,” which is required to drive vehicles, perform EVAs safely, operate tools, and manage complex machines. This is especially true when it comes to rovers and the lander elevator used by the Starship HLS – both of which will be used for the Artemis III and IV missions.

As Meagan Chappell, a Knowledge Management Analyst at NASA’s Langley Research Center, indicates, this will require the development of new functional vision support systems. That means helmets, windows, and lighting systems that can work together to allow crews to “see into the darkness while their eyes are light-adapted, in bright light while still dark-adapted, and protects their eyes from injury.” According to the NESC assessment, these challenges have not been addressed, and must be understood before solutions can be implemented.

In particular, they indicated how functional vision and specific tasks for Artemis astronauts were not incorporated into system design requirements. For example, the new spacesuits designed for the Artemis Program – the Axiom Extravehicular Mobility Unit (AxEMU) – provide greater flexibility so astronauts can walk more easily on the lunar surface. However, there are currently no features or systems that would allow astronauts to see well enough when transitioning between brilliant sunlight into dark shadow and back again without losing their footing.

The NESC assessment identified several other gaps, prompting them to recommend that methods that enable functional vision become a specific and new requirement for system designers. They also recommended that the design process for lighting, windows, and visors become integrated. Lastly, they recommended that various physical and virtual simulation techniques be developed to address specific requirements. This means virtual reality programs that simulate what it is like to walk around the LSP during lunar day and night, followed by “dress rehearsal” missions in analog environments (or both combined!).

Astronauts operating around the Lunar South Pole. Credit: NASA

As Chappell summarized, the simulations will likely focus on different aspects of the mission elements to gauge the effectiveness of their designs:

“Some would address the blinding effects of sunlight at the LSP (not easily achieved through virtual approaches) to evaluate [the] performance of helmet shields and artificial lighting in the context of the environment and adaptation times. Other simulations would add terrain features to identify the threats in simple (e.g., walking, collection of samples) and complex (e.g., maintenance and operation of equipment) tasks. Since different facilities have different strengths, they also have different weaknesses. These strengths and limitations must be characterized to enable verification of technical solutions and crew training.”

This latest series of recommendations reminds us that NASA is committed to achieving a regular human presence on the Moon by the end of this decade. As that day draws nearer, the need for more in-depth preparation and planning becomes apparent. By the time astronauts are making regular trips to the Moon (according to NASA, once a year after 2028), they will need the best training and equipment we can muster.

Further Reading: NASA

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Neutron Stars With Less Mass Than A White Dwarf Might Exist, and LIGO and Virgo Could Find Them

Most of the neutron stars we know of have a mass between 1.4 and 2.0 Suns. The upper limit makes sense, since, beyond about two solar masses, a neutron star would collapse to become a black hole. The lower limit also makes sense given the mass of white dwarfs. While neutron stars defy gravitational collapse thanks to the pressure between neutrons, white dwarfs defy gravity thanks to electron pressure. As first discovered by Subrahmanyan Chandrasekhar in 1930, white dwarfs can only support themselves up to what is now known as the Chandrasekhar Limit, or 1.4 solar masses. So it’s easy to assume that a neutron star must have at least that much mass. Otherwise, collapse would stop at a white dwarf. But that isn’t necessarily true.

It is true that under simple hydrostatic collapse, anything under 1.4 solar masses would remain a white dwarf. But larger stars don’t simply run out of fuel and collapse. They undergo cataclysmic explosions as a supernova. If such an explosion were to squeeze the central core rapidly, you might have a core of neutron matter with less than 1.4 solar masses. The question is whether it could be stable as a small neutron star. That depends on how neutron matter holds together, which is described by its equation of state.

Neutron star matter is governed by the Tolman–Oppenheimer–Volkoff, which is a complex relativistic equation based on certain assumed parameters. Using the best data we currently have, the TOV equation of state puts an upper mass limit for a neutron star at 2.17 solar masses and a lower mass limit around 1.1 solar masses. If you tweak the parameters to the most extreme values allowed by observation, the lower limit can drop to 0.4 solar masses. If we can observe low-mass neutron stars, it would further constrain the TOV parameters and improve our understanding of neutron stars. This is the focus of a new study on the arXiv.

Previous searches for low-mass neutron stars. Credit: Kacanja & Nitz

The study looks at data from the third observing run of the Virgo and Advanced LIGO gravitational wave observatories. While most of the observed events are the mergers of stellar-mass black holes, the observatories can also capture mergers between two neutron stars or a neutron star and a black hole companion. The signal strength of these smaller mergers is so close to the noise level of the gravitational wave detectors that you need to have an idea of the type of signal you’re looking for to find it. For neutron star mergers, this is complicated by the fact that neutron stars are sensitive to tidal deformations. These deformations would shift the “chirp” of the merger signal, and the smaller the neutron star, the greater the deformation.

So the team simulated how sub-white-dwarf mass neutron stars would tidally deform as they merge, then calculated how that would affect the observed gravitational chirp. They then looked for these kinds of chirps in the data of the third observation run. While the team found no evidence for small-mass neutron stars, they were able to place an upper limit on the hypothetical rate of such mergers. Essentially, they found that there can be no more than 2,000 observable mergers involving a neutron star up to 70% of the Sun’s mass. While that might not seem like much of a limit, it’s important to remember that we are still in the early stages of gravitational wave astronomy. In the coming decades, we will have more sensitive gravitational telescopes, which will either discover small neutron stars or prove that they can’t exist.

Reference: Kacanja, Keisi, and Alexander H. Nitz. “A Search for Low-Mass Neutron Stars in the Third Observing Run of Advanced LIGO and Virgo.” arXiv preprint arXiv:2412.05369 (2024).

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Webb Observes Protoplanetary Disks that Contradict Models of Planet Formation

The James Webb Space Telescope (JWST) was specifically intended to address some of the greatest unresolved questions in cosmology. These include all of the major questions scientists have been pondering since the Hubble Space Telescope (HST) took its deepest views of the Universe: the Hubble Tension, how the first stars and galaxies came together, how planetary systems formed, and when the first black holes appeared. In particular, Hubble spotted something very interesting in 2003 when observing a star almost as old as the Universe itself.

Orbiting this ancient star was a massive planet whose very existence contradicted accepted models of planet formation since stars in the early Universe did not have time to produce enough heavy elements for planets to form. Thanks to recent observations by the JWST, an international team of scientists announced that they may have solved this conundrum. By observing stars in the Small Magellanic Cloud (LMC), which lacks large amounts of heavy elements, they found stars with planet-forming disks that are longer-lived than those seen around young stars in our Milky Way galaxy.

The study was led by Guido De Marchi, an astronomer at the European Space Research and Technology Centre (ESTEC) in Noordwijk, Netherlands. He was joined by researchers from the INAF Osservatorio Astronomico di Roma, the Space Telescope Science Institute (STScI), Gemini Observatory/NSF NOIRLab, the UK Astronomy Technology Centre (UK ATC), the Institute for Astronomy at the University of Edinburgh, the Leiden Observatory, the European Space Agency (ESA), NASA’s Ames Research Center, and NASA’s Jet Propulsion Laboratory. The paper detailing their findings appeared on December 16th in The Astrophysical Journal.

James Webb Space Telescope image of NGC 346, a massive star cluster in the Small Magellanic Cloud. Credit: NASA/ESA/CSA/STScI/Olivia C. Jones (UK ATC)/Guido De Marchi (ESTEC)/Margaret Meixner (USRA)

According to accepted cosmological models, the first stars in the Universe (Population III stars) formed 13.7 billion years ago, just a few hundred million years after the Big Bang. These stars were very hot, bright, massive, short-lived, and composed of hydrogen and helium, with very little in the way of heavy elements. These elements were gradually forged in the interiors of Population III stars, which distributed them throughout the Universe once they exploded in a supernova and blew off their outer layers to form star-forming nebulae.

These nebulae and their traces of heavier elements would form the next generation of stars (Population II). After these stars formed from gas and dust in the nebula that underwent gravitational collapse, the remaining material fell around the new stars to form protoplanetary disks. As a result, subsequent populations of stars contained higher concentrations of metals (aka. metallicity). The presence of these heavy elements, ranging from carbon and oxygen to silica and iron, led to the formation of the first planets.

As such, Hubble‘s discovery of a massive planet (2.5 times the mass of Jupiter) around a star that existed just 1 billion years after the Big Bang baffled scientists since early stars contained only tiny amounts of heavier elements. This implied that planet formation began when the Universe was very young, and some planets had time to become particularly massive. Elena Sabbi, the chief scientist for the Gemini Observatory at the National Science Foundation’s NOIRLab, explained in a NASA press release:

“Current models predict that with so few heavier elements, the disks around stars have a short lifetime, so short in fact that planets cannot grow big. But Hubble did see those planets, so what if the models were not correct and disks could live longer?”

James Webb Space Telescope image of NGC 346, a massive star cluster in the Small Magellanic Cloud. Credit: NASA/ESA/CSA/STScI/Olivia C. Jones (UK ATC)/Guido De Marchi (ESTEC)/Margaret Meixner (USRA)

To test this theory, the team used Webb to observe the massive, star-forming cluster NGC 346 in the Small Magellanic Cloud, a dwarf galaxy and one of the Milky Way’s closest neighbors. This star cluster is also known to have relatively low amounts of heavier elements and served as a nearby proxy for stellar environments during the early Universe. Earlier observations of NGC 346 by Hubble revealed that many young stars in the cluster (~20 to 30 million years old) appeared to still have protoplanetary disks around them. This was also surprising since such disks were believed to dissipate after 2 to 3 million years.

Thanks to Webb’s high-resolution and sophisticated spectrometers, scientists now have the first-ever spectra of young Sun-like stars and their environments in a nearby galaxy. As study leader Guido De Marchi of the European Space Research and Technology Centre in Noordwijk put it:

“The Hubble findings were controversial, going against not only empirical evidence in our galaxy but also against the current models. This was intriguing, but without a way to obtain spectra of those stars, we could not really establish whether we were witnessing genuine accretion and the presence of disks, or just some artificial effects.”

“We see that these stars are indeed surrounded by disks and are still in the process of gobbling material, even at the relatively old age of 20 or 30 million years. This also implies that planets have more time to form and grow around these stars than in nearby star-forming regions in our own galaxy.”

Side-by-side comparison shows a Hubble image of the massive star cluster NGC 346 (left) versus a Webb image of the same cluster (right). Credit: NASA/ESA/CSA/STScI/Olivia C. Jones (UK ATC)/Guido De Marchi (ESTEC)/Margaret Meixner (USRA)/Antonella Nota (ESA)

These findings naturally raise the question of how disks with few heavy elements (the very building blocks of planets) could endure for so long. The researchers suggested two distinct mechanisms that could explain these observations, alone or in combination. One possibility is that a star’s radiation pressure may only be effective if elements heavier than hydrogen and helium are present in sufficient quantities in the disk. However, the NGC 346 cluster only has about ten percent of the heavier elements in our Sun, so it may take longer for a star in this cluster to disperse its disk.

The second possibility is that where heavier elements are scarce, a Sun-like star would need to form from a larger cloud of gas. This would also produce a larger and more massive protoplanetary disk, which would take longer for stellar radiation to blow away. Said Sabbi:

“With more matter around the stars, the accretion lasts for a longer time. The disks take ten times longer to disappear. This has implications for how you form a planet, and the type of system architecture that you can have in these different environments. This is so exciting.”

“With Webb, we have a really strong confirmation of what we saw with Hubble, and we must rethink how we model planet formation and early evolution in the young universe,” added Marchi.

Like many of Webb’s observations, these findings are a fitting reminder of what the next-generation space telescope was designed to do. In addition to confirming the Hubble Tension, the JWST observed more galaxies (and bigger ones!) in the early Universe than models predicted. It also observed that the seeds of Supermassive Black Holes (SMBH) were more massive than expected. In this respect, the JWST is doing its job by causing astronomers to rethink theories that have been accepted for decades. From this, new theories and discoveries will follow that could upend what we think we know about the cosmos.

Further Reading: NASA, The Astrophysical Journal

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James Webb’s Big Year for Cosmology

The James Webb Space Telescope was designed and built to study the early universe, and hopefully revolutionary our understanding of cosmology. Two years after its launch, it’s doing just that.

One of the first things that astronomers noticed with the James Webb was galaxies that were brighter and larger than our models of galaxy formation suggested they should be. They were like seeing teenagers in a kindergarten classroom, challenging our assumptions of cosmology. But while there were some breathless claims that the Big Bang was broken, those statements were a little overblown.

But still, big, bright, mature galaxies in the early universe are forcing us to reconsider how galaxy formation is supposed to proceed. Whatever nature is telling us through the James Webb, it seems to be that galaxies form far faster than we thought before.

Related to that, for several years cosmologists have recognized a certain tension in their measurements of the present-day expansion rate of the universe, called the Hubble rate. Appropriately called the Hubble tension, the difference comes when comparing measurements of the distant, early universe with measurements of the later, nearby universe.

There’s definitely something funky going on here, but cosmologists can’t figure out exactly what. It might have something to do with our measurements of the deep universe, or it might be because of our lack of understanding of dark matter and dark energy. Either way, the James Webb didn’t help anything by confirming that the tension is very, very real.

No matter what comes out of the Hubble tension problem, the James Webb is delivering spectacular results in other areas. One of its primary missions was to find evidence for Population III stars, the first generation of stars to appear in the universe. There are no such stars left in the modern-day cosmos, as they all apparently died off billions of years ago. So our only hope to detect them is to use super-telescopes like the James Webb.

This year a team reported the first tentative detections of a galaxy in the young universe that just might contain Population III stars. The detection is not confirmed, but hopefully upcoming observation campaigns will tell us if we’re on the right track.

No matter what, we know we have a lot left to learn about the universe, and that the James Webb will continue delivering results – and hopefully a few surprises – for years to come.

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