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According to the most widely accepted scientific theory, our Solar System formed from a nebula of dust and gas roughly 4.56 billion years ago (aka. Nebula Theory). It began when the nebula experienced gravitational collapse at the center, fusing material under tremendous pressure to create the Sun. Over time, the remaining material fell into an extended disk around the Sun, gradually accreting to form planetesimals that grew larger with time. These planetesimals eventually experienced hydrostatic equilibrium, collapsing into spherical bodies to create Earth and its companions.

Based on modern observations and simulations, researchers have been trying to understand what conditions were like when these planetesimals formed. In a new study, geologists from the California Institute of Technology (Caltech) combined meteorite data with thermodynamic modeling to better understand what went into these bodies from which Earth and the other inner planets formed. According to their results, the earliest planetesimals have formed in the presence of water, which is inconsistent with current astrophysical models of the early Solar System.

The research was conducted in the laboratory of Paul Asimow, the Eleanor and John R. McMillan Professor of Geology and Geochemistry at Caltech. The team was led by assistant professor Damanveer Grewal, the leader of the CosmoGeo Lab at Arizona State University (ASU) and a former postdoctoral scholar with the Division of Geological and Planetary Sciences at Caltech. Grewal and Asimow were joined by planetary scientists from the Massachusetts Institute of Technology (MIT), the University of California Los Angeles (UCLA), and Rice University.

Sample from a rare meteorite family revealing that its parent planetesimal had a layered structure with a molten core and solid crust (similar to Earth). Credit: Carl Agee, Institute of Meteoritics UNM/MIT

Grewal and his colleagues specialize in studying the chemical signatures of iron meteorites to gather information about the early Solar System. These meteorites are remnants of the metallic cores of the first planetesimals that did not accrete to form a planet and continue to orbit within our Solar System today. Over many eons, some of these objects fell into Earth’s gravity well and ultimately crashed to the surface. The chemical composition of these meteorites is of particular interest since it reveals a great deal about the environments in which they formed.

For one thing, the composition of planetesimals can reveal whether they (and Earth) formed closer to or farther away from the Sun. If the former scenario were the case, cooler conditions would have allowed Earth to retain water ice as a building block. If the latter is correct, Earth would have formed dry and obtained its water by some other means later on, which is what current astrophysical models suggest. According to these models, water was delivered to the inner Solar System via comets and asteroids billions of years ago, a period known as the Late Heavy Bombardment.

While water is no longer present in these meteorites, scientists can infer its existence from the presence of other elements. These include iron oxide (FeO), which occurs when iron is oxidization by exposure to water. A sufficient excess of water will drive the process further, creating ferric oxide (Fe2O3) and ferric oxyhydroxide, or FeO(OH) – the ingredients of rust. While the earliest planetesimals would have lost all traces of iron oxide long ago, Grewal and his team were able to determine how much was present by examining the metallic nickel, cobalt, and iron contents of these meteorites.

These three elements should be present in roughly equal ratios relative to other materials in the meteorite, which means that any “missing” iron would have been depleted through oxidation. As Asimow explained in a Caltech news release:

“Iron meteorites have been somewhat neglected by the planet-formation community, but they constitute rich stores of information about the earliest period of Solar System history, once you work out how to read the signals. The difference between what we measured in the inner solar system meteorites and what we expected implies an oxygen activity about 10,000 times higher.”

Artist concept of Earth during the Late Heavy Bombardment period. Credit: NASA’s Goddard Space Flight Center.

The team’s results indicate that meteorites believed to have originated in the inner Solar System had roughly the same amount of missing iron as meteorites from the outer Solar System. This suggests that both groups formed in a part of the Solar System where conditions were cool enough for water. It further implies that planets accreted water from the beginning, which could have profound implications for theories of how life emerged on Earth. “If water was present in the early building blocks of our planet, other important elements like carbon and nitrogen were likely present as well,” said Grewal. “The ingredients for life may have been present in the seeds of rocky planets right from the start.”

This represents a significant challenge for our current models for how the Solar System formed and evolved, which could indicate that conditions in the early inner Solar System were much cooler than previously thought. The results could also mean that Earth and its fellow rocky planets formed farther from the Sun and gradually migrated to their current orbits. However, as Asimow acknowledged, there is a degree of uncertainty when it comes to the study of ancient planetesimals, which means the results may not contradict current astrophysical models:

“However, the method only detects water that was used up in oxidizing iron. It is not sensitive to excess water that might go on to form the ocean. So, the conclusions of this study are consistent with Earth accretion models that call for late addition of even more water-rich material.”

Their study, titled “Accretion of the earliest inner Solar System planetesimals beyond the water snowline,” recently appeared in Nature Astronomy. Their research was made possible thanks in part to funding provided by NASA and through a Barr Foundation Postdoctoral Fellowship.

Further Reading: Caltech, Nature Astronomy

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We think of magnetic fields as a part of planets and stars. The Earth and Sun have relatively strong magnetic fields, as do more exotic objects such as neutron stars and the accretion disks of black holes. But magnetic field lines also run throughout galaxies, and even between the vast voids of intergalactic space. Magnetic fields are quite literally everywhere, and we aren’t entirely sure why. One idea is that faint magnetic fields formed during the earliest moments of the Universe. If that’s the case, we might be able to prove it through the distribution of dark matter.

The idea of mapping primordial magnetic fields with dark matter is a bit subtle. As far as we know, dark matter only interacts with regular matter gravitationally. It doesn’t interact with magnetic fields, so the mere presence of a magnetic field shouldn’t affect dark matter in any way. But magnetic fields do interact with charged regular matter such as electrons, and those electrons interact with dark matter gravitationally.

So the idea is that intergalactic magnetic fields would tend to cluster electrons and ionized intergalactic hydrogen along their field lines, making those regions of the intergalactic voids just slightly denser than the rest of the void. This would cause dark matter to cluster a bit along the field lines as well. The gravitational effect would be extremely tiny, but over the entire history of the Universe, it would add up. So if primordial magnetic fields did form in the early Universe, tendrils of dark matter should be present along the same lines.

Artist rendering of the dark matter halo surrounding our galaxy. Credit: ESO/L. Calçada

In a recent work in Physical Review Letters the authors argue that this effect would produce minihalos of dark matter. Just as galaxies are surrounded by a halo of dark matter due to gravitational clustering, faint halos of dark matter should exist around primordial magnetic field lines to do the gravitational tug of ionized matter along the field lines.

What’s interesting about this idea is that over time the charged ions and electrons would interact with the primordial magnetic fields and tend to cancel them out. The ions and electrons could even merge to create neutral hydrogen, so in the modern Universe, there would be no trace of these early magnetic fields in regular matter. But the microhalos of dark matter would still exist, and they could be seen through the gravitational lensing of distant light sources. These tendrils of dark matter could be the only evidence remaining of the earliest magnetic fields in the cosmos.

This study is purely theoretical, and current telescopes aren’t sensitive enough to measure the gravitational lensing effect of microhalos. But it’s interesting to see how dark matter can carry the history of the Universe in its structure, even for things that have long faded from view.

Reference: Ralegankar, Pranjal. “Dark Matter Minihalos from Primordial Magnetic Fields.” Physical Review Letters 131 (2023): 231002.

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There can’t be many ideas that beat the crazy yet ingenious idea of a rocket engine that actually uses part of the fuselage for fuel! Typically a rocket will utilise multiple stages so that excess weight can be jetisoned allowing the rocket to be as efficient as possible. Now a team in Scotland is working on a rocket engine that actually consumes part of its body to use as fuel, reducing weight and providing even more thrust so that greater payloads can be used. 

Rockets go back thousands of years from the earliest rocket propelled arrows used by the Mongolian empire to the mighty Saturn V rocket that took Apollo astronauts to the Moon, the principle has remained largely the same. Take a fuel, cram it inside a container of some sort, ignite it in some way and you can use it to propel something forwards or upwards… or actually backwards too now I think about it. 

The Apollo 10 Saturn V during rollout. Credit: NASA

Things are changing though. A team from the James Watt School of Engineering at University of Glasgow and led by Professor Patrick Harkness have developed the self-eating rocket engine! When the ‘autophage’ (from the latin for self-eating) fires it consumes part of its own body for fuel. 

It’s really quite an ingenious concept, essentially some fuel is stored up inside the rocket chamber itself. As the engine fires, some of the heat melts through the plastic of its own fuselage and as the plastic melts, it is fed into the chamber as fuel to suplement the usual liquid propellant. 

Using the rocket chamber itself as fuel means less fuel has to be carried and the mass saving can be used up by more massive payloads. There are further benefits too, as the rocket chamber is used in the combustion it will reduce the chances of space debris. 

The idea is not a new one though since the idea of a self-eating rocket was first discussed just over 80 years ago. The team from Glasgow have taken the concept a step further though by building one! The container was made out of polyethylene plastic which would burn as suplementary fuel along side the regular liquid propellant, a mix of gaseous oxygen and liquid propane. 

They succesfully fired the engine that they have called Ouroborous-3 which produced 100 newtons of thrust. The thrust was stable even through the autophage stage when the plastic case was providing a fifth of the total propellant used.  

Previous rocket tech used a solid propellant, for example the solid boosters on the side of the space shuttle and once this stuff was lit, whether you liked it or not, you were going in to space. This new design is controllable, indeed the team demonstrated how it was capable of being restarted, throttled and pulsed in an on/off pattern, all of which are necessary for an efficient rocket enginge. 

Source : Self-Eating Rocket Could Help UK Take a Big Bite of Space Industry

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When scientists detected phosphine in Venus’ atmosphere in 2020, it triggered renewed, animated discussions about Venus and its potential habitability. It would be weird if the detection didn’t generate interest since phosphine is a potential biomarker. So people were understandably curious. Unfortunately, further study couldn’t confirm its presence.

But even without phosphine, Venus’ atmosphere is full of chemical intrigue that hints at biological processes. Is it time to send an astrobiology mission to our hellish sister planet?

While the phosphine discussion petered out pretty quickly, there are other, more long-lived indications that Venus’ atmosphere contains chemical anomalies, some of which might relate to life. Some of the atmospheric gases appear to be out of thermodynamic equilibrium, for example. Adding to the complexity, scientists aren’t certain what the composition of large particles in the lower atmosphere is.

The authors of a new paper illustrate why Venus captures our chemical curiosity and suggest that it’s time for an astrobiological mission to satisfy it.

The paper is “Astrobiological Potential of Venus Atmosphere Chemical Anomalies and Other Unexplained Cloud Properties.” It hasn’t been peer-reviewed and published yet, but it’s available on the preprint server arxiv.org. The lead author is Janusz Petkowski, an astrobiology researcher in the Department of Earth, Atmospheric and Planetary Sciences at MIT.

“Scientists have been speculating on Venus as a habitable world for over half a century,” the authors write, “based on the Earth-like temperature and pressure in Venus’ clouds at 48–60 km above the surface.”

Most space-interested people know that Venus’ atmosphere is extremely dense ant hot. We also know that it’s dominated by carbon dioxide, that its other main component is nitrogen, and that it supports dense clouds of sulfuric acid. Other chemicals are present in only tiny, trace amounts.

There’s not much else to Venus’ atmosphere beyond CO2 and a small component of nitrogen. The trace elements add up to less than one percent of the atmosphere. Image Credit: By Junkcharts – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31595105

The atmospheric region between 48 to 60 km above the surface is particularly interesting. At that altitude, both the pressure and the temperature approach near Earth-like levels. Between about 52.5 km and 54 km, the temperature is between 20 °C and 37 °C.) At about 49.5 km above the surface, the pressure is the same as at Earth’s sea level. There’s no way that liquid water could be present on Venus’ surface, but in the atmosphere it’s possible.

That’s the backdrop for considering Venus’ potential habitability.

But there are ample chemical considerations, too, and in their paper, the authors outline one long-standing mystery in the planet’s atmosphere.

“In this paper, we review and summarize Venus’ long-lasting, unexplained atmospheric observations,
which have been acquired over the span of the last half-century,” they write.

A lot of the mystery around Venus concerns the so-called “unknown absorber(s).” As far back as the 1920s, ultraviolet observations showed unusual high-contrast features that move in conjunction with Venus’ upper cloud deck’s four-day rotation. Something is absorbing the UV light. “Much effort has gone into attempting to identify the substance(s) responsible for the absorption between 320–400 nm, but no proposed candidate satisfies all of the observational constraints, leading to the oft-used descriptive term ‘unknown UV absorber,'” the authors write.

Researchers have made a prolonged effort to understand what the absorber or absorbers might be, and some have made progress. Research has shown that sulphur allotropes and sulphur compounds could be responsible, and researchers have uncovered new pathways for their formation in Venus’ atmosphere. But these pathways are the result of simulations, not exploration. Not everyone agrees with these findings. There’s no consensus.

“Despite decades of effort and observations by two orbiting spacecraft in the 21st century (Venus Express
by ESA and Akatsuki by JAXA), none of the proposed candidate molecules have been found to entirely fit
the observational data,” the authors explain. The candidates either don’t match the profile well, or they’re not abundant enough. Some of the proposed candidates aren’t stable, either.

But it’s critical that we figure out what it is. “The unknown absorber is remarkably efficient, capturing more than 50% of the solar energy reaching Venus, with consequent effects on atmospheric structure and dynamics,” write the authors. Though the mystery persists, it’s a huge missing piece that stymies our efforts to understand the planet.

Some researchers propose that the UV absorber is a sign of cloud-based biological activity. “The spectral characteristics of the Venus clouds, including the strong UV absorption, are consistent with the spectrum of certain types of terrestrial bacteria,” the authors explain.

A composite image of the planet Venus as seen by the Japanese probe Akatsuki. The clouds of Venus could have environmental conditions conducive to microbial life. Credit: JAXA/Institute of Space and Astronautical Science

Another of the mysteries concerns lower clouds. A subset of cloud particles larger than 7 µm is unknown. Adding to the mystery is that some of them aren’t round. We know this from NASA’s Pioneer Venus mission. Since the particles, called Mode 3 particles, are non-spherical, they can’t be liquid droplets. “The nature and composition of the Mode 3 particles is debated with data presently in hand,” the authors write, making it clear that we need more data from a modern mission.

Some have proposed that the particles could be sulfuric acid, but the authors say data rules that out. If they’re not sulfuric acid, that works in favour of the idea that life could persist in the clouds. “This result could indicate unknown chemistry and is intriguing with regard to the possible presence of ‘life as we know it,’ which cannot withstand a concentrated sulfuric acid environment,” the authors explain.

It should be noted, however, that not all scientists agree that the large particles even exist and that calibration errors could be responsible for their detection instead.

The authors outline other reasons why only a biological mission to Venus can solve these mysteries. In-situ measurements from the Venera program and the VeGa balloons suggested that the atmosphere hosted non-volatile compounds necessary for life. Life as we know it requires metals, including iron. Venera found iron, while VeGa didn’t. More mystery waiting to be solved.

There are other unexplained components in Venus’ atmosphere. There are trace gases with abundance profiles that scientists can’t explain. Venera and Pioneer also found oxygen there. Nobody knows where it came from, and it’s a subject of frequent discussion. Other chemical detections add to the mystery and complexity.

The maddening thing about studying Venus from afar is that many of the observations could be explained by either biotic or abiotic processes. That’s why we need a biological mission.

NASA’s upcoming DAVINCI mission will send an orbiter and an atmospheric probe to Venus sometime in the 2030s. Image Credit: NASA

“The habitability of the Venusian clouds should also be explored by new in situ missions,” the author explains. Lots of scientists agree with them, including renowned planetary scientist Sara Seager. In fact, Seager goes even further, suggesting that a sample-return mission is needed.

There are missions to Venus coming in the future. NASA’s VERITAS mission and DAVINCI mission will both head to Venus, but not for several more years. DAVINCI will send a probe into Venus’s atmosphere for in situ observations, while VERITAS will map the surface in more detail.

In the meantime, the data we have is all the data scientists have to work with. While scientists are resourceful and determined, that’s not enough.

Only a mission to Venus that’s solely focused on biology and chemistry can solve the planet’s mysteries.

The post There are Mysteries at Venus. It’s Time for an Astrobiology Mission appeared first on Universe Today.

The fasted object ever made by humans has completed another milestone. The Parker Solar Probe recently celebrated the new year by completing its 18th flyby of the Sun.

After launching in 2018, Parker has spent the last five years zooming in close to the Sun and then back out again. We’ve reported on its achievements at various points in its journey, such as taking pictures of Venus or finding comets. And it still has almost two years to go on its planned seven-year mission. 

Over those seven years, mission planners have designed 24 perihelion events where the prove passes as closely as possible to the Sun. Each time, the instruments on the probe are taking as much data as possible. Those instruments had better be quick, as the probe is literally the fastest thing ever.

Fraser discusses the Parker Solar Probe.

Or ever made by humans, at least. On its 18th perihelion event at 7:56 PM on December 28th, 2023, Parker matched its previous fastest-ever speed of 635,226 kph (394,736 mph). That doesn’t leave much time for the instruments to collect much data, though the overall solar encounter lasted from December 24th through January 2nd. It passed as close as 7.26 million kilometers (4.51 million miles) from the surface of the Sun on this flyby. That is by far the closest any probe has even gotten to our Sun – intentionally, at least.

There are currently eight more planned solar encounters ahead for the mission, designed to end in December 2025 after its 26th flyby. Later this year, it will also complete its last flyby of Venus to gain even more speed as it travels. 

Data from the 18th flyby isn’t yet available for scientists to pour over, but the spacecraft did check in with a “hello” signal on January 5th, a few days after the planned flyby. Hopefully, that means it’s alive and well and will continue its orbit around the Sun, looking to provide even more insight into the details of heliophysics at an even more significant speed.

Video from the Applied Physics Laboratory describes Parker’s 16th encounter last year.
Credit – John Hopkins Applied Physics Laboratory

Learn More:
NASA – NASA’s Parker Solar Probe Completes 18th Close Approach to the Sun
UT – Wow. Parker Solar Probe Took a Picture of the Surface of Venus
UT – Parker Solar Probe Flies Through the Sun’s Outer Atmosphere for the First Time
UT – Parker Solar Probe Captured Images of Venus on its way to the Sun

Lead Image:
Artist’s depiction of the Parker Solar Probe
Credit – NASA

The post Parker Solar Probe Skims the Sun on its 18th Flyby appeared first on Universe Today.

Before planets form around a young star, the protosolar disk is populated with innumerable planetesimals. Over time, these planetesimals combine to form planets, and the core accretion theory explains how that happens. But before there are planets, the disk full of planetesimals is a messy place.

The history of rocky objects smashing into each other is written in the craters scarring the surfaces of the planets and moons. But that’s the macro scale of the history. There’s more to planetesimals than their eventual accretion into planets.

New research shows that these small bodies are subject to headwinds made of gas and particles in the protosolar disk that can strike them and throw rocky debris out into space. This is a new wrinkle in our understanding of how rocky planets form.

(A note on terminology: a protosolar disk is the disk of gas and dust that exists while the star at the center is forming. A protoplanetary disk is the same disk after the star has formed but while planets are still forming.)

The study is “Wind erosion and transport on planetesimals.” It’s published in the journal Icarus, and the lead author is Alice Quillen, Professor of Astronomy and Astrophysics at the University of Rochester.

The new study concerns planetesimals between 10 and 100 km in diameter embedded in the protosolar nebula. In these nebulae, the stars are not really stars yet. They’re young stellar objects that don’t undergo any nuclear fusion. So it’s not stellar winds that strike them; it’s the headwinds in the nebula itself. Those headwinds are made of the gas and dust in the disk and arise from the difference in velocity between the material in the disk and the planetesimal. Temperature and pressure differences in different regions of the protosolar disk also contribute.

A protosolar disk is a disk of material around a young stellar object that isn’t yet a star. It’s called a protoplanetary disk once the star has formed and begun fusion. Planetesimals are the building blocks of planets and are present in both stages of a disk’s evolution. Image Credit: NASA/JPL

“We consider the possibility that aeolian (windblown) processes occur on small, 1 to 100 km diameter, planetesimals when they were embedded in the protosolar nebula,” the authors write.

Planetesimals form via cohesion. As small particles collide with each other in the protosolar nebula, they stick together. But a young nebula is a chaotic, messy place. There are collisions which can either add more material to the planetesimals or remove material. Particles and gas can exchange angular momentum, and there’s also gas pressure. There’s a lot going on during this stage, which can last several million years.

Over time, enough particles stick together that a planetesimal takes shape.

But there’s gas pressure in the young disk, and as a planetesimal moves through it, it experiences it as a headwind full of particles. That headwind is strong enough to overcome the planetesimal’s surface cohesion.

“Aeolian (wind-driven) particle transport has occurred on many bodies in the Solar system, including Earth, Mars, Venus, Triton, Titan, Pluto, Io, and comet 67P/ChuryumovGerasimenko,” the authors write. “The ubiquity of aeolian processes in the Solar system suggests that planetesimal surfaces can be modified by protostellar-disk headwinds and the particles within them.”

According to the authors, the headwind in a protostellar disk is powerful enough to loft cm and smaller-sized particles off of planetesimals. This can happen on a planetesimal with a 10 km diameter in the inner Solar System.

Beyond that, in the outer Solar System, something different happens. Particles in the headwinds strike the planetesimals and remove micron-sized particles from the surface. These particles can be thrown into space or distributed back onto the surface of the planetesimal.

For planetesimals below about 6 km in diameter, erosion from particles in the headwind creates mass loss rather than accretion. Factors like wind velocity, headwind particle size, and material size affect the overall process.

The authors point to Arrokoth, a well-known Kuiper Belt Object, as an example. It’s a trans-Neptunian object that probably formed in the outer Solar System. It was likely created when two objects collided at a relatively low velocity. “Amongst Arrokoth’s most striking features are the smooth and undulating terrain present on its larger lobe (or head), also called Wenu,” the authors write.

Arrokoth is not only a trans-Neptunian object; it’s a Jupiter family comet. These comets began as Kuiper Belt Objects but were pulled into the inner Solar System by the gravity of the large gas giants. While other Jupiter family comets have cliffs, perched boulders, and chasms on their surfaces, Arrokoth’s surface is strangely smooth in comparison. Evidence shows that Arrokoth formed when the disk around the young stellar object that would become the Sun was optically thick. So its surface was unaffected by the luminosity coming from the young Sun. That indicates that another process shaped its surface.

“Winds from a protostellar disk could account for Kuiper Belt Object (486958) Arrokoth’s smooth undulating terrain,” they write, but only when there were a lot of particles and only when their velocity was low.

This composite image of the Kuiper Belt object 2014 MU69 (Arrokoth) came from data obtained by NASA’s New Horizons spacecraft as it flew by the object on Jan. 1, 2019. The authors of the new paper say that the headwind in the protosolar nebula could be responsible for Arrokoth’s smooth, undulating terrain. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute//Roman Tkachenko

This research is extremely detailed. But overall, it shows that aeolian processes can alter the surfaces of planetesimals and play a role in the planet formation process. There are many variables involved, like headwind velocity, gas pressure, particle size, and planetesimal velocity. Sometimes, the particles are removed from the planetesimal; sometimes, they splash back onto the surface.

The main variable is distance from the protostar. It plays a big role in the process. “The erosion or accretion rates are higher in the inner solar system where the density of the disk is higher,” the authors write.

“Interactions between particle-rich headwinds and planetesimals are likely to cause a variety of interesting phenomena which could be the focus of future studies,” the authors conclude.

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There are many different ways to get to Mars, but there are always tradeoffs. Chemical propulsion, proven the most popular, can quickly get a spacecraft to the red planet. But they come at a high cost of bringing their fuel, thereby increasing the mission’s overall cost. Alternative propulsion technologies have been gaining traction in several deep space applications. Now, a team of scientists from Spain has preliminary studied what it would take to send a probe to Mars using entirely electric propulsion once it leaves Earth.

Electric propulsion systems have several advantages over chemical rockets. While they will never be able to be scaled up enough to lift anything heavy into orbit, once in space, they are extraordinarily efficient at moving payloads where they need to go. While a typical chemical rocket requires 70-90% of its launch mass to be used as fuel, an electric propulsion system can get by with just 10-40% of its launch mass as fuel.

The tradeoff to be made is in thrust. Electric propulsion systems typically have a thrust at least four orders of magnitude smaller than that created by chemical rockets. Meanwhile, in space, its significant impact is that electric propulsion systems are much slower. But that might not be as much of a concern for uncrewed missions.

Fraser describes the underlying mechanics of an ion engine.

So far, no one has spent the time to consider just how much difference there would be between a Mars mission driven by electric rather than chemical propulsion. The closest study was one drawn up for a visit to Mars’ moons – Phobos and Deimos – that relied entirely on electric propulsion. In that study, the researchers found that the chemical propulsion option would require 2.5 times as much mass as the electric propulsion option. That would significantly decrease the overall cost of the mission.

In this new study, the researchers focused on a trajectory that would place a 2000 kg spacecraft into a polar orbit around Mars between 300 km and 1000 km. The 2000 kg weight limit was selected as a package that could contain equivalent scientific packages to the ExoMars orbiter that ESA worked on.

With those mission constraints, the researchers considered several different types of electric propulsion systems. They came up with an additional requirement – it must operate at the upper thrust range of many electric propulsion systems. A thrust of .1 N is the minimum required to enter into orbit around Mars successfully.

Electric Drives can be used for some pretty incredible thing, as described in this video with Dr. Sonny White.

This constraint led to the selection of the BHT-6000 as the mission’s primary propulsion system. It’s a Hall Effect thruster that operates with between 2 and 6kW of power and can use relatively common electrical propulsion propellants such as Xenon and Krypton. With this selection of propulsion, it was time to get to every astrodynamist’s favorite activity – modeling.

The researchers used a multi-body model to map out the gravitational impact of their selected trajectory. Then, they ran simulations of a mission with a standard chemical propellant and the BHT-6000. What they found seemed in line with general expectations of the advantages of electric propulsion.

In terms of speed, the chemical rocket was faster, but not egregiously so. A chemical rocket could make the journey in a little under a year, while a BHT-6000-powered mission would take approximately 3.2 years from launch. However, the weight of the chemical propulsion system would be 2.4 times that of the electric propulsion system. Even at a relatively conservative launch cost of $10,000 / kg, that would put the cost saving of an electric propulsion system at almost $30 million over the chemical alternative. All at the cost of a few more years of travel time to get the mission on station.

That is a tradeoff many space exploration agencies would gladly pay due to constrained budgets. But, so far, this is only a model as there is no planned deep space mission that would use this electric propulsion method as its primary propulsion system, though a few deep space missions, such as Hayabusa-2, already have. As the technology advances, though, it’s becoming more and more likely that future deep space missions, especially unmanned ones, will go to Mars.

Learn More:
Casanova-Álvarez, Navarro-Medina, & Tommasin – Feasibility study of a Solar Electric Propulsion mission to Mars
UT – The Most Powerful Ion Engine Ever Built Passes the Test
UT – Magnetic Fusion Plasma Engines Could Carry us Across the Solar System and Into Interstellar Space
UT – NASA Selects Aerojet Rocketdyne to Develop Solar Electric Propulsion for Deep Space Missions

Lead Image:
Artist’s impression of a solar electric propulsion system
Credit – NASA

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Based on satellite imagery, geologists have determined major cities on the U.S. Atlantic coast are sinking, some areas as much as 2 to 5 millimeters (.08-0.2 inches) per year. Called subsidence, this sinking of land is happening at a faster rate than was estimated just a year ago. In a new paper published in the Proceedings of the National Academies of Sciences, researchers say their analysis has far-reaching implications for community and infrastructure resilience planning, particularly for roadways, airport runways, building foundations, rail lines, and pipelines.

These coastal areas, which include population centers such as New York City, Baltimore, Virginia Beach and Norfolk, are also vulnerable to weather and storm issues. The land subsidence problem exacerbates any problems caused by increasingly intense storms due to climate change.

“Continuous unmitigated subsidence on the U.S. East Coast should cause concern,” said lead author Leonard Ohenhen, a graduate student working with Associate Professor Manoochehr Shirzaei at Virginia Tech’s Earth Observation and Innovation Lab, in a press release from Virginia Tech. “This is particularly in areas with a high population and property density and a historical complacency toward infrastructure maintenance.”

The research team, from Virginia Tech and the U.S. Geological Survey, used satellite imagery and radar data to create digital terrain maps that show exactly where the land subsidence presents the most risks to vital infrastructure. They used data from multiple years, which showed a large area of the East Coast is sinking at least 2 mm (.08 inches) per year, with several areas along the mid-Atlantic coast  — up to 3,700 square kilometers, or more than 1,400 square miles — is sinking more than 5 mm (0.2 inches) per year. Adding complexity to the issue is that the current rate of global sea level rise is estimated to be about 4 mm per year.

A map of primary, secondary, and interstate roads on Hampton Roads, Norfolk, and Virginia Beach, Virginia (top panel); and John F. Kennedy International Airport, New York (bottom panel). The yellow, orange and red areas on these maps denote areas of sinking. Images by Leonard Ohenhen/ Virginia Tech.

“We measured subsidence rates of 2 mm per year affecting more than 2 million people and 800,000 properties on the East Coast,” Shirzaei said. “We know to some extent that the land is sinking. Through this study, we highlight that sinking of the land is not an intangible threat. It affects you and I and everyone, it may be gradual, but the impacts are real.”

In their paper, “Slowly but surely: Exposure of communities and infrastructure to subsidence on the US east coast,” the team wrote that they evaluated the subsidence-hazard exposure to population, assets, and infrastructure systems/facilities along the US east coast: “Here, we show that 2,000 to 74,000?square km land area, 1.2 to 14 million people, 476,000 to 6.3 million properties, and greater than 50% of infrastructures in major cities … are exposed to [these] subsidence rates.”

“Here, the problem is not just that the land is sinking. The problem is that the hotspots of sinking land intersect directly with population and infrastructure hubs,” said Ohenhen. “For example, significant areas of critical infrastructure in New York, including JFK and LaGuardia airports and its runways, along with the railway systems, are affected by subsidence rates exceeding 2 mm per year. The effects of these right now and into the future are potential damage to infrastructure and increased flood risks.”

“This information is needed. No one else is providing it,” said Patrick Barnard, a research geologist with the USGS and co-author of the study. “Shirzaei and his Virginia Tech team stepped into that niche with his technical expertise and is providing something extremely valuable.”

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Way back when the cosmos was only five billion years old, a powerful explosion happened in a group of young galaxies halfway across the Universe. It sent out a blast of radiation from one member of that distant galaxy group.

On June 10, 2022, the Square Kilometer Array pathfinder telescope in Australia picked up a fast radio burst (FRB) emanating from the site. The Very Large Telescope in Chile confirmed its distance. Now, Hubble Space Telescope provides a look at the specific galaxy where the FRB originated. It’s kinda weird.

Hubble’s view suggests that the event, called FRB 20220610A, happened in a galaxy-rich part of the Universe. That’s pretty unexpected since most FRBs happen in isolated galaxies, not necessarily in clusters. That alone makes this event a “weirdo” outlier in the annals of fast radio burst detections.

“It required Hubble’s keen sharpness and sensitivity to pinpoint exactly where the FRB came from,” said astronomer Alexa Gordon of Northwestern University in Evanston, Illinois. “Without Hubble’s imaging, it would still remain a mystery as to whether this was originating from one monolithic galaxy or some type of interacting system. It’s these types of environments – these weird ones – that are driving us toward better understanding the mystery of FRBs.”

Fast Radio Bursts Pose a Puzzling Mystery

A fast radio burst is just what it sounds like: a huge blast of radio waves, accompanied by a visible-light component. FRBs can outshine a galaxy for a very short time, which catches astronomers’ attention. They’ve been observed for decades and the first one was discovered in 2007. Astronomers still aren’t sure exactly what sets them off. “We are ultimately trying to answer the questions: What causes them? What are their progenitors and what are their origins? The Hubble observations provide a spectacular view of the surprising types of environments that give rise to these mysterious events,” said co-investigator Wen-fai Fong, also of Northwestern University.

Of course, there are a lot of theories about the origins of these events. Black holes or neutron stars may play a role in creating these outbursts. An FRB may get stirred up in an intense neutron star called a magnetar. These objects exist in various “flavors”, so their FRBs might also have different aspects.

An artist’s impression of the ultra-long period magnetar—a rare type of star with extremely strong magnetic fields that can produce powerful bursts of energy. Credit: ICRAR

Magnetars have incredibly strong, twisted magnetic fields (hence the name magnetar). Sometimes those magnetic fields get so twisted that they break and reconnect. This happens on other stars and on the Sun, although not at the same intensity as a magnetar. The whole process, from snap to reconnection releases a tremendous amount of energy. On a magnetar, the “snap” could be what generates the flash of light and release of radio waves that characterize a FRB. The heat released would vaporize any nearby material, such as gas and dust.

Solving the Mystery of FRB Origins

If a magnetar isn’t involved in every FRB, maybe black collisions play a role. Or, it’s possible that some interaction between a black hole and a massive object orbiting around it could cause one of these explosions. The merger of neutron stars could do it, too. At least, those are two other theories to explain these blasts. Some astronomers also suggest that very energetic and huge supernova explosions might be enough to create an FRB. And, there are a variety of other ideas, involving black holes, pulsars, and dark matter.

To get to the root cause of FRBs, astronomers need to observe more of them at high resolution. As it is now, when the signals from one hit Earth, radio telescopes gather the first data. Then, once astronomers figure out the location, they send information to various ground-based and orbiting telescopes. Those observatories can then focus on the other wavelengths of light coming from the explosion. Hubble Space Telescope plays a crucial role in delivering the sharpest possible images of the distant regions of space where FRBs occur. “We just need to keep finding more of these FRBs, both nearby and far away, and in all these different types of environments,” said Gordon.

In addition, astronomers want to know what are most likely environments for FRBs. Are most of them confined to individual, isolated galaxies? Or, can they occur in the galaxy cluster neighborhood? Also, since these events seem to occur at great distances, that means they happened early in cosmic history. The most distant one so far sent its light across 8 billion light-years to reach us. What happened in their galaxies in those early epochs to spur on the incredible blasts of energy released? These and other questions await further observations of FRBs.

For More Information

Hubble Finds Weird Home of Farthest Fast Radio Burst
A Fast Radio Burst in a Compact Galaxy Group at z~1

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Any astronomical instrument dubbed “Lobster Eyes” is bound to grab attention. It’s actually unlike scientists to give anything creative names, take the big red coloured storm on Jupiter which resembles a spot…aka the Great Red Spot! Lobster Eyes is the name adtoped by the X-ray telescope that just been launched from China and will scan the sky looking for X-rays coming from high-energy transients. 

The instrument, which is more properly called the Einstein Probe, is a collaboration between The Chinese Academy of Sciences (CAS), the European Space Agency (ESA) and the Max Planck Institute for Extraterrestrial Physics (MPE). It was launched on 9 January at 07:03 on a Chang Zheng 2C rocket from China. Having launched succesfully, it reached its orbit at an altitude of 600 kilometres, circling the Earth once every 96 minutes. Its orbital parameters mean it can observe the entire night sky in only three orbits. Now it has settle into its orbit, it has begun preparing its mission to scour the skies for x-ray bursts from neutron stars and black holes. 

In order for the probe to deliver on the required efficiency, it is home to two instruments, the Wide-field X-ray Telescope (WXT) and the Follow-up X-ray Telescope (FXT). Together they afford a wide field and sensitive view of the sky in X-rays. The optical design of the WXT is unique, loosely resembling a mult-segment mirror telescope. It is a modular configuration with thousands of square fibre optics that collect and channel light onto the detectors. It is for this reason it got the nickname ‘Lobster Eyes’.  In one image, it can obeserve nearly one-tenth of the sky in a single capture. As soon as a new X-ray source is detected by the WXT, then FXT fires up and captures a more detailed, sensitive view of the object. 

ESA have been a key partner in the project and played a major part in its development. They supported the testing and callibration of the detectors and optics of WXT, along with MPE they developed the mirror assembly of one of the FXT telescopes and provided the system to deflect unwanted electrons away from the detectors. As the mission progresses, they will also use ESA ground stations to collect the data, and in return for all this, ESA will get 10% of the data. 

Now the probe has been succesfully deployed it is tuning in to X-ray radiation. X-rays are among the more energetic types of radiation and studying them helps us to understand more about the energetic processes in the Universe. Such events might include neutron star collisions, supernovae and numerous black hole events. 

This X-ray image of Cygnus X-1 was taken by a balloon-borne telescope, the High Energy Replicated Optics (HERO) project. NASA image.

It will be a few months yet before data starts to flow back from Lobster Eyes since it has to first go through a callibration phase that is expected to last around six months. On completion, the probe is expected to spend at least three years watching the sky, waiting for X-ray events to help develop our understanding of the cosmos. 

Source : Einstein Probe lifts off on a mission to monitor the X-ray sky

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When we look at the Moon, either through a pair of binoculars, a telescope, or past footage from the Apollo missions, we see a landscape that’s riddled with what appear to be massive sinkholes. But these “sinkholes” aren’t just on the Moon, as they are evident on nearly every planetary body throughout the solar system, from planets, to other moons, to asteroids. They are called impact craters and can range in size from cities to small countries.

Impact craters are caused by rocks ranging in size from dust particles to a few kilometers in diameter that collide with a planetary body’s surface at incredible speeds. The result is not only a giant hole in the ground, but the impact also shoots out material from beneath the surface, splattering it in all directions, known as a ray system or ejecta. Some craters are so big that scientists refer to them as giant impacts. But why are impact craters so important to study?

“Collisions are a pervasive physical process during planet formation and evolution,” Dr. Sarah T. Stewart, who is a Professor of Earth and Planetary Sciences at UC Davis, tells Universe Today. “While the frequency of collisions is low today compared to the main stages of planet growth, they provide key insights into planetary dynamics, subsurface composition, and internal structure. Collisions also shaped the evolution of life on Earth, which in some cases is well documented such as the Chixculub crater event and its influence on the demise of the dinosaurs. In other cases, such as the roles of collisions in the origin of life, it is less well understood but an active area of research.”

Also known as the Chixculub impact event, this event is hypothesized to be a massive impact that occurred on Earth approximately 65 million years ago when an asteroid 10-kilometers (6-miles) in diameter struck just off the northern coast of the Yucatán Peninsula in Mexico. Researchers estimate the resulting blast was equivalent to approximately 100 million megatons while producing a core greater than 5,500 degrees Celsius (10,000 degrees Fahrenheit) and a crater spanning 180 kilometers (110 miles) in diameter and 20 kilometers (12 miles) deep.

Aside from the extreme heat and massive shock waves, the impact also produced sulfuric acid rain from debris raining down onto the planet, loss of ozone, and a massive dust cloud that blocked sunlight, resulting in the extinction of 75 percent of all life on the Earth. But despite the devastating consequences that the Chixculub impact event had for life on Earth, what can studying giant impacts and impact cratering teach us about finding life on other worlds?

“Our views on the relationship between life and impacts have changed dramatically over the past two decades,” Dr. Stewart tells Universe Today. “When I was a student, I was taught that impacts would sterilize a planet’s surface and inhibit the rise of life. Today, the origin of life community is calling upon impacts to provide chemical and thermal perturbations that would aid pre-biotic chemistry. Since collisions are so common during planet formation, the view has shifted to increase the role of collisions and possible frequency of life as we know it.”

The reason why the massive crater from the Chixculub impact event is so well-hidden is due to the planetary surface processes that shape our planet, most notably from erosion, weathering, volcanism, and plate tectonics. These processes have also essentially erased up to millions of other impact craters that have occurred throughout the Earth’s approximate 4.6-billion-year history. This is in stark contrast to our Moon and thousands of other planetary bodies throughout the solar system, including planets, moons, and asteroids, which still have craters that could have been produced billions of years ago.

While these processes have erased nearly all impact craters across the globe, one of the most well-preserved impact craters in the world is Meteor Crater, which is located approximately 60 kilometers (37 miles) east of Flagstaff, Arizona. This crater was created approximately 50,000 years ago by an object hypothesized to be 50 meters (150 feet) in diameter, resulting in the crater we see today, which is just under 1.2 kilometers (0.7 miles) in diameter. Therefore, along with all these unique aspects, what are some exciting reasons for both how and why upcoming students should study impact craters?

“Impact craters are always an interesting target for robotic (and human) exploration of other bodies because they provide access to subsurface materials,” Dr. Stewart tells Universe Today. “Scientists are still trying to understand how the biggest craters form and how to interpret variations that must be related to the interior properties. Humans are now doing exciting experiments related to planetary defense — like the DART mission. Planetary protection requires understanding many of the same physical processes as during natural impact events.”

Dr. Stewart tells Universe Today, “Impact craters are beautiful, complex, and intriguing planetary features” while encouraging college students to check out Planetary Impacts Community Wiki, which is a science resource for all things impact-related, including online tools, datasets, news, and much more.

What new discoveries will scientists make about impact craters in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

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About 16,000 light-years away, a massive star experienced an unusual dimming event. This can happen in binary stars when one star passes in front of the other. It can also be due to intrinsic reasons like innate variability. But this star dimmed by as much as one-third, a huge amount.

What happened?

The star is named RW Cephei. It’s one of the largest stars we know of. Its radius is almost 1,000 times as large as the Sun’s. Put another way, it’s almost as large as Jupiter’s orbit.

Many stars, maybe all of them, exhibit some variability in their luminosity, though it’s often very small. RW Cephei is considered a semiregular variable star, which means its variation is definite on occasion but is otherwise irregular. But this dimming episode was too pronounced to be attributed to intrinsic variability, and RW Cephei has no binary companion.

Astronomers working with Georgia State University’s CHARA Array spotted the dimming event last year. CHARA is an array of six 1-metre telescopes that work in conjunction as an interferometer. The team behind the new research presented their findings at the 243 AAS Conference, and it’s also published in The Astronomical Journal. Its title is “The Great Dimming of the Hypergiant Star RW Cephei: CHARA Array Images and Spectral Analysis.” The lead author is Narsireddy Anugu, an astronomer and optical systems scientist at the CHARA Array.

CHARA consists of six one-meter telescopes and related facilities. Image Credit: CHARA/GSU

“We made our first CHARA observations in December 2022, just before the winter weather closure, but the results were so remarkable we decided to pursue additional observations once the star was accessible again,” said Anugu.  Anugu led an international team of scientists in a quest to make the first close-up pictures of RW Cephei to determine the source of the fading.

Astronomers Wolfgang Vollmann and Costantino Sigismondi announced in 2022 that RW Cephei had faded dramatically over the previous few years. The pair reported their findings in The Astronomers Telegram. “The star is significantly dimming instead of rebrightening,” the pair wrote. “This phenomenon undergoing on RW Cep might be similar to the one that occurred on the red supergiant Betelgeuse at the end of 2019.”

Astronomers figured out that Betelgeuse’s dimming was likely caused by an ejection of gas that cooled into dust and blocked some of the star’s light. Could a similar mechanism be behind RW Cephei’s dimming? Maybe, but Betelgeuse didn’t dim by one-third, whereas RW Cephei did.

CHARA stands for Center for High Angular Resolution Astronomy. The high angular resolution allowed astronomers to get a pretty detailed look at the star, even though it’s about 16,000 light-years away. RW Cephei is also a huge hypergiant, which helps. CHARA can see things smaller than a human on the Moon.

CHARA Array false-color images of RW Cephei from December 2022 (left) and Jul 2023 (right). The patchy appearance results from dust created by a huge ejection from the star. The star is huge, but it is so far away that it appears about one million times smaller than the full moon in the sky. By July 2023, the star was brightening again. Image Credit: CHARA/Anugu et al. 2023

CHARA images showed that the star wasn’t round, a very unusual finding. But scientists couldn’t be sure if that was correct. They used specialized computer programs to refine the image.

“The spacing of the CHARA telescopes induces a level of uncertainty in the exact details of the pictures, so we need intelligent algorithms to recover the whole image,” said Fabien Baron. Baron is a co-author of the paper and also wrote the computer algorithms.

These two images from the research show RW Cephei in two separate bands. The H band is on the left, and the K band is on the right. The images show an asymmetry between the star’s brighter left-hand side and the dimmer right-hand side. Image Credit: Anugu et al. 2023

The images show that the star’s surface is undergoing convulsions, altering its round appearance. There are also brighter and darker patches on its surface, and its overall appearance changed during the ten-month period of observations that covered its dimming and re-brightening. “The most striking features in the reconstructed images are the large variations in brightness across the visible hemisphere of the star,” the researchers write in their paper.

Another of the study’s co-authors, Katherine Shepard of the Apache Point Observatory in New Mexico, decided to try a different tactic. She used a camera to record both visual and infrared light coming from RW Cephei. Her observations showed that the dimming was much more pronounced in visible light than in infrared.

Those observations were a telltale sign that dust was blocking the light. The researchers concluded that the same thing that happened to Betelgeuse happened to RW Cephei. The star shed some of its gas in a massive outburst, and the gas cooled into dust that blocked one-third of the star’s visible light.

“The Great Dimming of RW Cep may be the latest in a series of mass ejections over the last century.”

From “The Great Dimming of the Hypergiant Star RW Cephei: CHARA Array Images and Spectral Analysis.”

Both Betelgeuse’s dimming and RW Cephei’s dimming are due to mass loss.

This comparison image shows the star Betelgeuse before and after its unprecedented dimming. The observations, taken with the SPHERE instrument on the ESO’s Very Large Telescope in January and December 2019, show how much the star has faded and how its apparent shape has changed. Image Credit: ESO/VLT/SPHERE

Aging stars lose mass as they burn their nuclear fuel. This weakens their gravity, and the aging star is unable to hold onto all of the material in its outer layers. Though there are many unanswered questions about the details of the process, both Betelgeuse and RW Cephei show that mass loss can occur in periodic violent outbursts. These outbursts then block the star’s light for a period of time before being dissipated. As the dust dissipates, the star begins to return to its normal brightness.

“The Great Dimming of RW Cep may be the latest in a series of mass ejections over the last century,” the authors write in their paper. “Thus, the current fading may be the latest of continuing mass ejection and dust formation episodes, and the newly formed dust now partially obscures the visible hemisphere.”

“We suggest that the maximum light time may have corresponded to a particularly energetic convective upwelling of hot gas that launched a surface mass ejection event,” the authors explain. “This gas is now cooling to the point of dust formation, and the part of the ejected cloud seen in projection against the photosphere causes the darker appearance of the western side of the star.”

The researchers also point out that the duration of these dimming events is related to the size of the star and the dust cloud it ejects. Betelgeuse is smaller than RW Cephei, and its event lasted about one year, while RW Cephei’s event may last several years. Even more massive stars like Canis Majoris, with a radius over 14 times that of the Sun, could experience episodes that last decades.

RW Cephei’s current eruption is likely one of several massive eruptions the star has experienced in the last century. Similar mass loss events will probably plague the star as it evolves toward its demise.

“This one was special because the cloud was ejected in the direction of Earth,” said CHARA Director Douglas Gies, “so we were in the right place to witness the full effects of the cataclysm.

The post A Giant Star is Fading Away. But First, it Had an Enormous Eruption appeared first on Universe Today.

The most evocative astronomy images take us across space and time to stars and galaxies billions of light-years away. Nestled at the center of this one, taken by the Hubble Space Telescope, is a collection of three galaxies. They’re not all that close together, although they appear to be in this image. What’s fascinating about this image is that it’s a fine example of an Einstein gravitational ring—and its discovery was enabled by members of the public!

Let’s examine this image in more detail. Start with the central point source of light. It’s a foreground galaxy called SDSS J020941.27+001558.4 that lies nearly three billion light-years away. It’s likely home to millions or billions of stars, planets, nebulae, and other objects. There’s another galaxy, called SDSS J020941.23+001600.7, that appears just above the central one—and it, too, is home to millions of stars.

A cropped version of the release image. The central point is the galaxy gravitationally lensing the background object. Courtesy NASA/ESA/STScI.

Both of these galaxies look like they’re surrounded by a reddish ring of light. Believe it or not, that’s also a galaxy. But, what we see is its distorted image. It’s very distant and we see it as it was when the Universe was only 2.6 billion years old.

Warping a Galaxy into an Einstein Ring

So, the distant lensed galaxy—HerS J020941.1+001557—isn’t ring-shaped. It just appears that way due to a fantastic confluence of gravitational effects. The galaxy lies almost directly behind the closer one (the central point of light). As the distant galaxy’s light travels across space, it moves through the gravitational field of the intervening galaxy. That “bends” the light and distorts the appearance of the galaxy into the ring shape we see here. It’s called an “Einstein Ring” because the gravitational field of the galaxy (or in some cases an intervening galaxy cluster) creates a “lens” that distorts the light.

An almost perfect Einstein Ring as seen by Hubble Space Telescope. The background galaxy and foreground lensing galaxy are in an almost exact line with each other.

Einstein’s theory of general relativity predicts that strong gravitational fields affect light as it passes through (or nearby). If all the pieces are in a perfect line with each other (that is, the background galaxy, the gravitational source, and Earth) then you get a perfect ring shape. Even a small deviation from a perfect lineup will result in a gravitational arc or partial ring. That’s what we see here.

Finding Einstein Rings Via Space Warps

While Einstein rings are relatively rare, examples of gravitational lensing exist across the Universe. As it turns out, lensed images of distant galaxies and quasars provide interesting science. Just as an example, the amount of lensing that distorts a distant object’s image tells astronomers a lot about the lensing galaxy or galaxy cluster. Once they have that information, researchers can use it to “reconstruct” the background galaxy and learn more about its stars. Lensing offers a way to see ancient galaxies, and can even track such things as supernova explosions in those distant objects. Scientists use lensed objects to learn more about dark matter and its properties, and even to estimate the expansion rate of the Universe.

Hubble and other telescopes have taken many images of these cosmic lineups, more than there’s time to examine fully. A group of astronomers gathered up images from the Subaru Telescope’s “Hyper Suprim-Cam” (HSC) instrument and put them into a database. Those images are part of a huge survey of the sky that HSC performed. And, scientists estimated that there could be hundreds of lenses captured in HSC’s images. They decided to make them available via Zooniverse, a citizen-science portal. Then, they invited members of the public to sort through the images as part of a project called Space Warps. The goal was to look for lenses. In particular, they wanted to find Einstein Rings.

An example of a gravitational lens found in HCS data. Courtesy Space Warps.

In January 2014, citizen scientists on the Spacewarps site identified this lens in the HSC data. It was the result of many hours of gravitational lens classifications performed on the HSC data. They were one of four groups that found this lens, and it was also identified in images from the Canada-France-Hawai’i Telescope, the Herschel telescope, and the Planck probe. Since that time, the lens has been studied by many other telescopes, including Hubble.

Using Lenses to Probe the Universe

Gravitational lenses like this one provide a unique way to study early epochs of cosmic time. The careful study of warped galaxies and quasars gives insight into what they looked like when the Universe was very young. We can follow their formation, the creation (and deaths) of their stars, and how smaller galaxies combined to form larger ones. Lensed images of active galactic nuclei might also give some serious hints as to the formation of central supermassive black holes in early history.

Think of gravitational lenses as a way to probe dim and distant areas of the Universe. They’re almost like time machines, giving us a clearer look at ancient cosmic events and processes. Some of these lenses are not as dramatic as this one, but even the weaker ones show us glimpses of more distant objects and provide insight into the gravitational structures that create them.

For More Information

So Near, or So Far?
Searching for Strong Gravitational Lenses in the Hyper Suprime-Cam (HSC) Survey

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