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James Joyce's tome 'Finnegans Wake' famously breaks the rules of normal prose through its unusual, dreamlike stream of consciousness, and new work in chaos theory takes a closer look at how Joyce's challenging novel stands out mathematically. Researchers compared the distribution of punctuation marks in various experimental novels to determine the underlying order of 'Finnegans Wake' and by statistically analyzing the texts, researchers found the tome exhibits an unusual but statistically identifiable structure. The wide singularity spectrum was perfectly symmetrical, meaning sentence length variability follows an orderly curve.

Our understanding of Venus' water history and the potential that it was once habitable in the past is being challenged by recent observations.

Citizen science is such a great concept. Using the combined computing power of a gazillion (exaggeration) desktop and laptops to churn through data is an excellent and efficient way of analysing volumes of data. This has been shown yet again as a star has been identified to be hurtling out to intergalactic space! Most stars in the Milky Way are not travelling fast enough to be able to escape its immense gravity but the suspected brown dwarf is travelling at 1.5 million km/h, fast enough to escape. 

The concept of using members of the public to support scientific endeavours dates back further than you might think. One of the earliest examples can be seen in the 19th century when the Christmas Bird Count was launched by the Audubon Society in 1900. It encouraged members of the public to track bird populations. When it comes to space science projects like SETI@Home are among those that spring to mind. 

A home PC running SETI at Home helping to churn through observational data Credit: SETI@home

Another citizen science project ‘Planet 9’ was launched by Backyard Worlds and to date, it has 82,690 volunteers signed up. The goal is to hunt for possible distant planets in our Solar System or previously unidentified brown dwarfs in our solar neighbourhood. It takes images from NASA’s Wide-field Infrared Survey Explorer (WISE) and shares them with its volunteers who then study them for objects that are moving. 

While hunting for objects worthy of study, a team of volunteers; Martin Kabatnik, Thomas P.Bickle and Dan Caselden identified a fast moving object which became known by the catchy title CWISE J124909.08+362116.0. Observations were scheduled after its discovery by several ground based instruments that showed it was moving so fast that it will eventually escape the gravitational pull of the Milky Way, heading out to intergalactic space. It’s the first object with a mass smaller than or similar to that of a star that has been seen travelling at such eye watering speeds – 1.5 milllion km/h! To mark the citizen scientists contribution they are named as co-authors to the study which has recently been published in the Astrophysical Journal Letters. 

Artist’s concept of the Wide-field Infrared Survey Explorer as its orbit around Earth. Credit: NASA/JPL

Quite what CWISE J1249 is remains a little bit of a mystery at the moment. It has a low mass suggesting either a low mass star or possibly a gas giant planet or maybe something in between known as a brown dwarf. It has also been found to have less iron and other metals in the core than other stars and brown dwarfs. The composition suggests it may be quite old and perhaps one of the first generations of stars from the Milky Way. If it is a brown dwarf then in itself it is not particularly rare. ‘Planet 9’ has discovered more than 4,000 of them alone but none are travelling at such a great speed that they will escape the Galaxy. 

It’s not just the nature of the object that is perplexing astronomers, its high speed to has been the subject of much debate. One theory suggests it could have been a part of a binary system with a white dwarf. The white dwarf would slowly accrete material from its companion leading to an explosion when the material reaches a critical point. This event may have provided the energy to accelerate the object out of the system and beyond.  Alternatively it may have been a part of a cluster which was ejected through gravitational interactions. 

Source : NASA Citizen Scientists Spot Object Moving 1 Million Miles Per Hour

The post Citizen Scientists Find a Star Escaping the Milky Way appeared first on Universe Today.

The latest research on caffeine reveals why coffee and decaf can be so good for your health, but energy drinks can be lethal

Empty space is nothing but. According to the weird rules of quantum mechanics, it’s actually filled with an endless amount of energy, known appropriately enough as vacuum energy.

Quantum mechanics is super weird. One of the lessons of the quantum is that particles, like electrons and photons and neutrinos and whatnot, aren’t what they seem to be. Instead, each of the particles that we see in nature is actually just a piece of a much larger, grander entity. These grander entitles are known as quantum fields, and the fields soak every bit of space and time, all throughout the universe.

There is a quantum field for every kind of particle: one field for the electrons, one for the photons, and so on. These fields are invisible to us, but they make up the fundamental building blocks of existence. They are constantly vibrating and buzzing. When the fields vibrate with enough energy, particles appear. When the fields die down, the particles disappear. (Another way to look at this is to say what we call a “particle” is really a localized vibration of a quantum field). When two particles interact, it’s really just two pieces of quantum fields interacting with each other.

So if you think about all the particles that make up your body, all the electrons and protons and neutrons, those particles are just local vibrations of entities that span the entire cosmos. Neat.

These quantum fields are always vibrating, even when those vibrations aren’t strong enough to produce a particle. If you take a box and empty out all of the stuff – all the electrons, all the photons, all the neutrinos, all the everything – the box is still filled with these quantum fields. Since those fields vibrate even in isolation, that means that the box is filled with invisible vacuum energy, also know as zero-point energy – the energy of these fundamental vibrations.

This means that the vacuum of the universe is really made of something. There’s no such thing as a true vacuum; wherever you go, there are always vibrating quantum fields.

We know that the vacuum energy – this incessant boiling and vibrating of the quantum fields – interacts with the everyday world. For example, electrons inside of atoms occasionally move to more distant orbits away from the nucleus. There’s no reason for the electrons to make their way back down, until they get jostled by the quantum fields, prompting them to fall back into their normal orbital place.

I know this all sounds weird and new-agey, but it’s a real thing. Everywhere you go in the universe, there’s always something.

The post The Secrets Hiding in the Vacuum appeared first on Universe Today.

Computer code dating back to the 1960s is still vital to banks, airlines and governments, but programmers familiar with the language are in short supply. Now AI models are being trained to fill the skills gap

In 2021, the Listener Letter fracas erupted in New Zealand when seven professors at Auckland University argued that the indigenous “way of knowing,”  Mātauranga Māori (MM), while valuable in anthropology and sociology classes, should not be taught, as the government planned, as coequal with modern science.  The seven signers were right: while MM does contain some empirical knowledge obtained by trial and error, it’s also a mixture of that empiricism with religion, spirituality, morality, teleology, legends from word of mouth, and guidelines for proper behavior. That stuff doesn’t belong in science class, but they keep trying to sneak it in anyway.

Nevertheless, because the entire country has been captured by a woke mentality that holds the indigenous people as sacred, and their legends as sacrosanct, the signers of the Listener letter were demonized, threatened, and had some of their jobs downgraded. Further the Royal Society of New Zealand investigated the two members who signed the letter. (They were eventually exculpated.)

Since then, the drive to make MM coequal to science, and replace modern knowledge with Māori legends and tales, continues, even under a new and more conservative government.  And many people were “offended” by the letter; that is, they claimed it was hurtful to the indigenous people and damaged higher education. As I wrote on July 10, the Vice-Chancellor of Auckland University, Dawn Freshwater, issued a statement that said this in part:

A letter in this week’s issue of The Listener magazine from seven of our academic staff on the subject of whether mātauranga Māori can be called science has caused considerable hurt and dismay among our staff, students and alumni.

While the academics are free to express their views, I want to make it clear that they do not represent the views of the University of Auckland.

The University has deep respect for mātauranga Māori as a distinctive and valuable knowledge system. We believe that mātauranga Māori and Western empirical science are not at odds and do not need to compete. They are complementary and have much to learn from each other.

This view is at the heart of our new strategy and vision, Taumata Teitei, and the Waipapa Toitū framework, and is part of our wider commitment to Te Tiriti [the 1840 Treaty of Waitangi] and te ao [Māori] principles.

But the braver academics continued to beef, and so Vice-Chancellor Freshwater, the top official of Auckland Uni, promised in both August and December of 2021 that she would commission a series of academic debates and symposia on MM versus modern science. Her promises included these statements:

We will be setting up a series of VC lectures, panels and debating sessions, both within the University and externally, to address this and other topics. Universities like ours have an important thought-leadership role to play on these issues, which we embrace, while recognising that we need to foster an environment within which such debates can take place positively, respectfully and constructively.

. . . . I am calling for a return to a more respectful, open-minded, fact-based exchange of views on the relationship between mātauranga Māori and science, and I am committing the University to action on this.

In the first quarter of 2022 we will be holding a symposium in which the different viewpoints on this issue can be discussed and debated calmly, constructively and respectfully. I envisage a high-quality intellectual discourse with representation from all viewpoints: mātauranga Māori, science, the humanities, Pacific knowledge systems and others.

To give a short summary, these promises amounted to what comes out of the south end of a wildebeest facing north.

The debates and symposia never materialized, and I predicted as much.  Yes, there were at least three symposia, but they were purely rah-rah affairs boosting MM and indigenous knowledge, devoid of any dissenting views or debate, much less robust intellectual debate. Dean Freshwater simply brushed the issue under the rug in favor of further burnishing Auckland Uni’s worship of MM.

In light of this, I wrote Dean Freshwater in July of this year—THREE YEARS after she’d made her unfulfilled promise—asking her when the debates would happen between advocates of MM and advocates of modern science. I could do this because I’m not a Kiwi and won’t suffer professionally simply by asking this question. You can see my letter to VC Freshwater here.

I received no response from Freshwater, but she delegated her chief of staff to respond to me, and I got this email on August 7.

Dear Dr Coyne,

I write in response to your 06 July message to Vice-Chancellor Dawn Freshwater in reference to Mātauranga Māori and science at the University of Auckland. As it happens, the University began holding an annual symposium on Mātauranga Māori in 2022, and our third event is scheduled for 11 September of this year. This symposium is open to the University community and focusses on different aspects of Māori knowledge systems (mātauranga). Our two events to date have each provided an opportunity for robust engagement. In addition, during this same period the University’s Pro Vice-Chancellor Māori, Te Kawehau Hoskins, and Prof Alison Jones have led open discussions on a range of topics relating to Mātauranga and its relation to science, in every Faculty and a number of service divisions across the University. Please know that the Vice-Chancellor’s position on this has not changed: respectful, open-minded, fact-based exchange of views—as enabled by the kinds of activities mentioned above—are essential within research universities such as ours. Thank you for your continued interest in this important topic. Cordially, Brian

Brian C. Ten Eyck, EdD
Poumatua Kaimahi | Chief of Staff
Tari o te Ihorangi | Office of the Vice Chancellor
Waipapa Taumata Rau | University of Auckland

This letter is a masterpiece of disingenous rhetoric. Check out the link to the “annual symposium” in Ten Eyck’s letter. Do you see any dissent or pushback in the summary below? Neither did I.

The University of Auckland, Waipapa Taumata Rau, is hosting its first Mātauranga Māori Symposium, exploring Te Ao Toi (Māori arts) and creative expression, with a diverse range of experts.

The symposium, set to occur annually with a focus on looking at different aspects of Mātauranga Māori, or Indigenous knowledge, will take place on Thursday 24 November and be held at Waipapa Marae at the University’s City Campus.

It will feature speakers who are experts in their respective fields, ranging from: Indigenous art history and architecture; moko signatures and iwi histories and traditions to whakairo (carving), weaving, multimedia installation, visual arts, photography, and the revival of Māori aute.

Speakers will include Waipapa Taumata Rau’s Associate Professor Ngarino Ellis, Te Ahukaramū Charles Royal, Bernard Makoare, Maureen Lander MNZM, Rongomai Grbic-Hoskins, Makareta Janke and Nikau Hindin.

Pro Vice-Chancellor Māori Te Kawehau Hoskins says the University is looking forward to opening this space to celebrate, share and engage with Mātauranga.

Several anonymous viewers of this symposium told me that there was no debate at all; one of them wrote me this:

This response is disingenuous. There have been presentations on MM but no opportunity to present different viewpoints. In other words, there has been no symposium fitting the description of the one promised by the VC in August 2021.

I’m told that there was a single pushback question from the floor, but it was largely sidestepped.

In other words, Vice Chancellor Freshwater lied when she promised a civil but robust debate on science vs. MM. My guess is that she knew when she made this promise that the debate would never take place. The University and VC Freshwater’s behavior are shameful.

And I’m pretty sure these debates never will happen. The entire curriculum of Auckland University, including its science offerings, is being captured by concepts from MM (more to come later), a capture heavily watering down the amount of science Auckland students will learn and giving them, instead, a big dose of postmodern philosophy of science. I’ll give one example of a “science” course, lacking any science, in a later post.

At any rate, the whole country is also subject to this ideological capture, despite the “progressive” Prime Minister Jacinda Ardern being replaced by the more moderate Christopher Luxon.  The whole science curriculum of the country, from primary school through university, is in dire straits, accompanied by layoffs of faculty and staff.

Since I’m the only person outside of New Zealand to call the country repeatedly to account, and to point out the dissimulation of Vice-Chancellor Freshwater, my cry in the wilderness is made in hopes that things will change. But they won’t, for so long as the indigenous people are seen as sacred and their way of knowing immune from criticism or debate, the country’s educational system will be swirling down the drain.

************

To show you how much rancor this issue creates, here’s a comment I got from a Kiwi on this post (the address is clearly fake). Needless to say, I didn’t allow it to go through, but now seems an appropriate time to show it (“Aotearoa” is the Māori word for “New Zealand”):

fuckjerrycoyne
jerrycoynedefendsepsteinpedos@gmail.com

kiwi here. please none of you ever come to aotearoa, you racist fucks. kill yourselves, instead.

Though I’ve been busy with a number of physics and writing tasks, I’ve been beefing up the “Reader Resources” section of this website, devoted to extending the experience of readers of my book. [BTW, the audiobook is due out at the end of September.]

The book has many endnotes (available separately here, in case [like me] you hate paging back and forth between the text and the endnotes, and would like to have the endnotes more easily available on a separate screen.) A number of these endnotes have asterisks, and for those endnotes I promised to provide more information here on this website. Well, that information is going up, step by step.

For example:

In Chapters 1-3, I’ve added information to endnotes that cover a wide range of topics, some historical, some about basic physics, and some on quite advanced subjects (such as how to precisely define the relativity principle [note 1 of chapter 2] and on the cosmic microwave background interplays with the relativity principle [note 1 of chapter 3]).

If any of these topics interest you, click on the relevant chapter heading to go to the webpage that has the added information; or go to the Reader Resources page that has all the chapters. Again, comments are welcome!

• Chapter 1 Overture 1
  • Note 2: On Einstein Quotations
• Part I: Motion
  • Note 2: How to Measure Earth’s Shape and Size
• Chapter 2 Relativity: The Greatest Illusion 15
  • Note 1: Isolated Bubbles
  • Note 2: Earth’s Rotation
  • Note 8: Planes’ Relative Speeds
• Chapter 3 Coasting: Easier Than It Appears 29
  • Note 1: Relativity and the Cosmic Microwave Background
  • Note 3: The Sun and the Earth

. I’m hoping that readers of this blog and of the book will enjoy this new material, and will also let me know if they have questions, corrections, or suggestions as to how I could improve the material further.

Scientists have found significant concentrations of a type of PFAS chemical in the air deep in the Amazon rainforest, suggesting it travelled over 100 kilometres from an industrial hub

Solar power is on the upswing. In 2023, 407–446 GW of solar power was installed globally, bringing the total to 1.6 TWdc. To put this into perspective, this was 55% of new power capacity added to energy production. For the first time, a renewable energy source contributed the most to new capacity. In 2024 so far solar is 75% of new capacity. In the US this was 60% of new power generation (capacity is the potential to make energy at any given time, while generation or production is the actual energy produced). In 2023 solar made up 5.5% of world energy production.

The reason for the increase in solar is that it’s the cheapest form of new energy. According to the International Energy Agency (IEA), solar electricity costs $30–60/MWh in Europe and the US, and $20–40/MWh in China and India. Solar is also the safest, with the fewest numbers of deaths per TWh produced (0.02, compared to the worst, 32.72 for brown coal). Because solar is clean and environmentally friendly, making solar cheaper and more efficient will only enhance its advantages. As is often discussed here, there are other considerations to the overall strategy of energy production, such as intermittency, grid storage, and grid upgrades, but we are not close, at least globally, to running into significant issues. We can take solar from the current 5.5% to at least 30% without too much issue, and can push higher with some infrastructure investment.

Along the lines of making solar power better and cheaper – let’s talk about Luminescent Solar Concentrators (LSCs). If we want to make solar power more efficient there are a few approaches. We could make the conversion of photons to electrons (the photovoltaic effect) more efficient. Right now commercial silicon solar panels have an efficiency of 22-24%, which is pretty good. The theoretical limit of silicon is about 29%, and newer materials, like perovskite, have an even higher potential efficiency.

Another approach is to have some kind of layered solar panel, where each layer may have efficiencies in the 20% range but the different layers have different peak efficiencies in terms of wavelength (color) of light, and there are multiple chances for each photon to be absorbed and converted into energy. Yet another approach is a solar collector – bringing more photons to the photovoltaic cell. Mirrors, for example, are an efficient way of redirecting light to a photovoltaic cell.

LSCs are a method of solar concentration. They use luminescent material to absorb light and then re-emit that light (luminesce). This has several advantages. First, LSCs are efficient at collective diffuse light. Solar panels work best with direct light, and the more direct the better. This is why there is a huge advantage to orienting a panel toward the sun, and for large installations even following the sun with movable panels. But LSCs don’t care – they can collect diffuse or scattered light from any direction with equal efficiency. They can then re-emit that light at a specific wavelength (color), and that light can be directed through a process called total internal reflection. This is like a fiber optic cable, where all light that hits the interface at the surface of the cable is reflected internally, so it travels down the cable and never leaves it.

What this means is that you can have a system of LSCs that are arranged to gather diffuse or direct light from any direction. These LSCs then give off light which travels down a fiber to a photovoltaic where the light is made into electricity. The LSCs are semi-transparent and can be of different colors. If you are thinking of a frond of leaf-like LSCs, then you are on the right track. LSCs are like leaves, and they can be arranged just like leaves, connecting to central fibers and brining energy to the photovoltaic device. In fact, trees have evolved to have a very efficient arrangement of leaves. They absorb light, but also scatter light so that it can be collected by other leaves.

LSCs can already be cost effective, compared to solar panels. They are cheaper to make – mostly just glass or plastic with a luminescent covering. PVs, by contrast, are relatively expensive for the same surface area. So it is more cost effective to have cheap LSCs covering a wide area and bringing light to the more expensive PVs. They also avoid the need for expensive tracking systems. Further, they can be made to be more modular, easier to upgrade and replace. The cost competitiveness improved further with larger area covered, and greater variability in light intensity and scattering.

LSCs are still on the steep part of the technology curve. A recent study presents ways to make them even more efficient, by reducing the size of each LSC and bunching them in a leaf-like structure. The hope is that this approach will make LSCs more scalable, cost effective, and efficient. There already is an LSC industry, but it is small compared to the PV industry. We may, however, be getting close to a shift.

It’s possible that in the future we will not have large fields of solar panels tracking the sun and collecting energy, but fields of artificial trees covered with leaf-like LSCs collecting sunlight and directing it down to their trunks where PVs turn the photons into energy.

The post Luminescent Solar Concentrators for Solar Power first appeared on NeuroLogica Blog.

The use of cocaine only took off in Europe during the 19th century, after the drug was chemically isolated from coca leaves, but new evidence suggests much earlier use

Cost is a major driving factor in the development of space exploration missions. Any new technology or trick that could lower the cost of a mission makes it much more appealing for mission planners. Therefore, much of NASA’s research goes into those technologies that enable cheaper missions. For example, a few years ago, NASA’s Institute for Advanced Concepts (NIAC) supported a project by Michael VanWoerkom of ExoTerra Resource to develop a lander mission that could support a sample return from Europa. Let’s examine what made that mission different from other Europa mission architectures.

The Nano Icy Moons Propellant Harvester (NIMPH) mission relies on three main advancements for one significant result: a 10x reduction in the overall mission cost. That reduced cost comes mainly from a single fact—the mission’s weight has dropped below the threshold where it can be launched by an Atlas V rather than the SLS, as similar missions would require.

The mission cost estimated for an SLS-launched Europa lander was around $5 billion, making it prohibitively expensive for NASA or any other agency without significant sacrifices to other missions. ExoTerra estimates that, by using several weight-reducing technologies, they could bring the mission price tag down to $500 million—a much more reasonable sum to garner support from one of the government space programs.

Video describing the mission concept.
Credit – NASA 360 YouTube Channel

Three different technologies would enable this weight and cost to drop. First would be the solar electric propulsion (SEP) system initially designed for use on DART. The second would be a micro in-situ resource utilization (µISRU) system, and the third would be a power-beaming system between the lander and an orbiter.

Let’s first look at the overall mission architecture to understand how each contributes. In NIMPH, a combined orbiter lander will use an Atlas V rocket to get into Earth orbit. Then, a solar electric propulsion system (SEP) was initially designed for use on the DART asteroid redirect test. Although it was not used during the DART mission, the NEXT ion thruster was part of the spacecraft that launched, and, despite suffering from some technical challenges, it could have allowed the spacecraft to reach its destination. A similar, lightweight SEP system could get NIMPH to the Jupiter system, but it could also get the sample back to Earth after the lander collected it.

Just how the lander can get that sample back off the icy moon is the focus of the next major technological step – the µISRU system. NIMPH’s architecture would require using the local ice as a propellant. A lander would literally sublimate the ice under its feet, suck up the resultant water vapor, electrolyze it to split it into oxygen and hydrogen, and then liquefy it to store it for use in getting a 1 kg ice core sample back into orbit.

Fraser discusses the missions planned for Jupiter’s system in the near future.

To do all of this requires power, though, and a lander with a radioisotope thermal generator or similar commonly used power generation system would be prohibitively heavy. So, why not utilize the massive solar array required for the SEP system and beam some of that power down to the lander? That is the concept behind the power beaming system, estimated to produce around 2 kW of power in the Jovian system, about 1.8  kW of which could be beamed directly to a lander. 

After the core has been collected and safely launched back into space using a specially designed LOx-LH2 engine that uses the water collected by the µISRU system, the lander meets up with the orbiter. The SEP system kicks back on and delivers the lander back to Earth orbit, where it once again detaches and rides back to Earth’s surface inside a standard reentry module.

There are some nuances to this entire mission architecture. For example, the SEP system wouldn’t work at full capacity in the Jovian system, so a much smaller LOx / Methane propulsion system is needed to maneuver the orbiter into position. Additionally, the lander would likely have to leave its legs embedded in the Europan ice, as the sublimation process it uses to collect fuel would likely embed them in place. 

Budgetary constraints are always a consideration in deep space exploration, as Fraser discusses in this video.

Plenty of development work on all these systems must be completed before any such mission is ready for launch. And most likely, some of the need for the scientific understanding would be met by the Europa Clipper mission set to launch later this year for $4.25 billion – not far off the 10x times expense that was the original impetus for the more capable NIMPH mission design. And while NIMPH did receive a Phase II NIAC grant, it hasn’t been selected for further development as far as we have found. So, as of now, this novel combination of mass-saving technologies will not be delivering an icy Europan sample any time soon – but maybe someday it will.

Learn More:
ExoTerra Resource / Michael VanWoerkom – Nano Icy Moons Propellant Harvester Final Report
UT – Europa Might Not Be Able to Support Life in its Oceans
UT – We Might Find Life Just Under the Surface on Europa
UT – Europa Clipper Could Help Discover if Jupiter’s Moon is Habitable

Lead Image:
Depiction of the NIMPH mission architecture.
Credit – Michael VanWoerkom

The post A Europan Lander Could Return an Ice Core For A Fraction of the Cost of Europa Clipper appeared first on Universe Today.

A dog's mouth is likely less 'dirty' than a meth mouth.

The post Licking first appeared on Science-Based Medicine.

An analysis of daily carbon dioxide emissions since 1970 has revealed increasingly large spikes that appear to be caused by growing energy use during extreme weather events

If I were to summarize how and why I do what I do, I might put it this way.

Meanwhile, in Dobrzyn, Hili is having trouble being a clairvoyant:

Hili: I do not see the future.
A: It’s not visible from here.

Hili: Nie widzę przyszłości.
Ja: Stąd jej nie widać.

How common are Earth-like exoplanets—also called exo-Earths—and which exoplanetary systems should we target to find them? This is what a recently submitted study hopes to address as a team of researchers investigated potential targets for the planned Habitable Worlds Observatory (HWO), which was recommended during the Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020) and is slated to launch in the 2040s. Most notably, HWO will use the direct imaging method to identify exo-Earths, and this study holds the potential to create a more scientifically cost-effective approach for identifying and studying exoplanets.

Here, Universe Today discusses this incredible research with Dr. Stephen Kane, who is a Professor of Planetary Astrophysics at UC Riverside and lead author of the study, regarding the motivation behind the study, significant results, potential system candidates for identifying exo-Earths, the significance of using the direct imaging method, and how this research could influence the 2030 decadal survey. Therefore, what was the motivation behind the study?

“The Habitable Worlds Observatory (HWO) is a direct imaging mission that was the top-ranked priority from the last Astrophysics decadal survey,” Dr. Kane tells Universe Today. “Part of the current effort is to select the most suitable stars that will be the target of HWO observations. There is presently a list of 164 stars on the HWO target list that the community is working with. Since some of the HWO targets are known to already have planets, I conducted a dynamical analysis of those systems to determine if a terrestrial planet in the Habitable Zone (HZ) could maintain a stable orbit.”

Out of those 164 stars in the study, 30 host a total of 70 known planets: 11 systems with 1 planet, 7 systems with 2 planets, 6 systems with 3 planets, 4 systems with 4 planets, 1 system with 5 planets, and 1 system with 6 planets. The system with 5 planets is HD 75732, more commonly known as 55 Cancri, and is located approximately 41 light-years from Earth. The five planets range in size between 8 Earth masses (planet e) and approximately 3 Jupiter masses (planet d), with the orbit of planet f at least partially traversing the HZ throughout its approximate 260-day orbit. The system with 6 planets is HD 219134, also called Gliese 892, and is located approximately 21 light-years from Earth. The six planets range in size between approximately 4.37 Earth masses (planet c) to more than 98 Earth masses (planet h), with the orbit of planet g hypothesized to partially traverse the HZ during its orbit based on a 2015 study and 2021 study.

For the study, the researchers used a series of computer models to calculate the plausible size of each star’s habitable zone, referred to as a dynamically viable habitable zone (DVHZ). The team then inserted a terrestrial planet into the habitable zone to ascertain if it could maintain a stable orbit for the 10,000,000-year duration of the computer model based on the current planetary population in each system, also known as system architecture. Therefore, what were the most significant results from the study and what follow-up studies are in the works?

“We investigated 30 stars on the HWO target list and found that 11 of those have a HZ that is severely impacted by the presence of a giant planet in the system,” Dr. Kane tells Universe Today. “This shows that there needs to be a much more thorough analysis of the remaining HWO target stars to determine if they might have similar dynamical problems. We are already planning a detailed radial velocity study of those stars to search for additional planets.”

Regarding which exoplanetary systems are the most promising candidates for identifying exo-Earths, Dr. Kane tells Universe Today, “Actually, what we do in our study is identify the LEAST promising targets by ruling out the presence of Earth mass planets in the HZ of those systems. Amongst those systems is the bright star pi Mensae, which hosts a giant planet whose orbit sends it regularly crashing through the HZ, ensuring that no habitable planets can exist there.”

Identifying and studying exoplanets is conducted through a variety of detection methods, including transit, radial velocity, gravitational microlensing, timing, and direct imaging. For the transit method, astronomers collect data on the dip in starlight that occurs when an exoplanet passes in front of it. For the radial velocity method, astronomers detect tiny wobbles that a star exhibits as it tugs on an exoplanet orbiting it. For the gravitational microlensing method, astronomers use a star’s gravitational field as a lens when it is almost exactly alignment with a distant star, magnifying the distant star within the front star’s gravitational field. When this happens, the gravitational field of a present exoplanet in the front star influences the front star’s gravitational field.

For the timing method, also called the transit-timing variation method, astronomers used data from an exoplanet that was detected using the transit method to try and find other planets within the system by detecting changes in the timing of the first planet caused by another planet. For the direct imaging method, astronomers used a coronagraph to block the brightness of a star, revealing exoplanets that would have otherwise been lost in the star’s glare.

Of the 5,743 exoplanets confirmed by NASA, 74.5 percent are from the transit method, 19 percent are from the radial velocity method, 3.9 percent are from microlensing, 1.4 percent are from the direct imaging method, 0.52 percent are from the transit-timing variation method, with the remaining from other methods, including eclipse timing variations, orbital brightness modulation, pulsar timing, astrometry, pulsating timing variations, and disk kinematics. With the planned Habitable Worlds Observatory, astronomers plan to use the direct imaging method, despite it achieving one of the lowest numbers of detected exoplanets. Therefore, why was the direct imaging method chosen for the HWO mission, and is the direct imaging the most viable method for identifying exo-Earths? If not, what method(s) would work best?

“We currently primarily use indirect methods to detect and characterize exoplanets,” Dr. Kane tells Universe Today. “Though these methods can be used to infer planetary properties such as mass, radius, and some atmospheric composition, this can only be achieved for a very limited number of planets. Direct imaging provides much more additional information, such as detailed atmospheric composition, and may even be used to infer surface topography and rotation rate.”

As noted, HWO was recommended during the Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020), the latter of which is sponsored by the National Research Council of the National Academy of Sciences and is a report conducted approximately every 10 years to ascertain the current state of the field of astronomy and astrophysics and the direction of research for the following 10 years. Along with pursuing further research on black holes, neutron stars, and galaxy evolution, Astro2020 also emphasized the search for habitable exoplanets and extraterrestrial life, and HWO was born from previous proposed missions known as the Habitable Exoplanet Observatory (HabEx) and Large Ultraviolet Optical Infrared Surveyor (LUVOIR). Therefore, with HWO being recommended by the 2020 decadal survey, how could the results from this study influence HWO being discussed in the 2030 decadal survey?

“Our results refine the HWO target list and so strengthen the science output of the mission,” Dr. Kane tells Universe Today. “The elimination of nearby bright targets may mean that HWO will need to shift to fainter, farther targets which, in turn, may require a larger telescope to achieve the same goals. HWO is an exciting mission and will provide incredible insights into the prevalence of habitable planets. As we learn more about the nearest planetary systems, we will greatly increase the odds of the success for HWO.”

How will HWO help discover Earth-like exoplanets in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Earth-like exoplanets might be in short supply for the Habitable Worlds Observatory appeared first on Universe Today.

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