Daily Archives: December 16, 2023

The biography of our home galaxy may be due for some revisions. Thats because a bar-shaped collection of stars at the center of the Milky Way appears to be much younger than expected.

The bar is a prominent feature of our galaxy (SN: 6/25/21). It spans thousands of light-years and links the galaxys spiraling arms of stars, making them resemble streams of water coming from a spinning lawn sprinkler. In computer simulations of the Milky Ways evolution, the bar tends to form early in the galaxys roughly 13-billion-year lifetime. But the ages and locations of metal-rich stars suggest the bar finished forming just a few billion years ago, researchers report. The study, submitted November 28 to arXiv.org, is in press at Astronomy & Astrophysics Letters.

These metal-rich stars are basically like fossil records of ancient stars that are telling the story of our home galaxy, says Samir Nepal, an astrophysicist at the Leibniz Institute for Astrophysics Potsdam in Germany.

Stars with large proportions of metal elements are built from the remnants of stars that have since exploded, ejecting the metals they forged from lighter elements. Those spewed metals enrich the materials in the core of galaxies like the Milky Way, which is why a new generation of metal-rich stars can form only deep inside galaxies. The spinning bar at the center of the Milky Way then scattered some of those stars throughout our galaxy.

Using data from the European Space Agencys Gaia space telescope, Nepal and colleagues reconstructed the development of the Milky Way bar through its influence on the distribution of metal-rich stars (SN: 5/9/18). They inferred the bars history, just as you might deduce where the batters stand in a baseball game by looking at the flight of the balls they hit, even if you cant see home plate.

In tracking the ages of the metal-rich stars, the researchers identified a burst of star formation in the central part of the galaxy that petered out about 3 billion years ago. The downturn seems to mark the end of the Milky Way bars developmental phase, the researchers report. After that burst, they say, the inflow of new material into the bar probably dropped off substantially. That suggests the bar we see today is a stable feature thats about 10 billion years younger than the galaxy as a whole.

The new insights about the metal-rich stars are like the tip of the iceberg of data coming from the Gaia telescope, says astrophysicist Cristina Chiappini, also with the Leibniz Institute for Astrophysics Potsdam. Assuming the revised age estimate of the bar is confirmed, future models of the galaxys evolution will have to account for why the bar developed so late.

The study has broader implications than correcting the history of our galaxy, says Ortwin Gerhard, an astrophysicist at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who was not involved in the research. The possibility of detailed observations of the motions and chemical abundances of stars in the Milky Way, particularly based on [data] from the Gaia satellite, he says, means we can expect to learn about the evolution of bars [in other galaxies] generally by studying the bar in the Milky Way.

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A bar of stars at the center of the Milky Way looks surprisingly young - Science News Magazine

This post is part of a series advertising the newly-formed Rainbow Village. The Rainbow Village is a gathering space centered in supporting, celebrating, and building community with people of color at AAS meetings. The space is designed for folks to connect with each other, share and celebrate milestones at the AAS meeting, and grow together through exploratory (salon-style) discussions. For a broader overview of the Rainbow Village and the organizations working to create this space, see our introduction post. Today we interview astrochemist Ashley Walker, Black in Astro (BiA) President and PhD student at Howard University.

This interview has been edited for clarity.

Astrobites has had a longstanding relationship with Black in Astro, but could you quickly describe Black in Astro and its mission for some of our newer readers?

Black in Astro was created from love. It was created from compassion for Black people, for Black people all over the diaspora, and our mission is to continuously support Black people, whether youre in astronomy, whether youre no longer in the field, whether you want to be in the field, whether youre an aerospace engineer, an artist. Its just something that is for the culture, and for everyone. Our goal is to primarily support all our people, all the Black people and our allies around the world.

Black in Astro is a constant fixture at AAS meetings. You run your own sessions, you run your own social events, how do the AAS meetings help you achieve your goals as an organization?

The AAS has been extremely supportive in our mission. I will say, its really exciting to be back in a Black city for the first time in 20 years. Its fantastic to go back and also see how they support other people of color, how we have the CSMA, and how theyre helping them get ready with booths and making sure that everyone knows each other. And from what Ive seen, its a jam packed session full of a lot of early career things this year. So Im really excited to see how thats gonna go.

Black in Astro is partnering with AAS CSMA (the Committee on the Status of Minorities in Astronomy), LUMA (the League of Underrepresented Minoritized Astronomers), and VanguardSTEM for the Rainbow Village. Could you talk a little bit about that partnership and whats exciting and what youll be doing at the Rainbow Village?

To come together and work on the Rainbow Village has been just a joy to see. What can you expect from the Rainbow Village? You can definitely expect mentorship, you can expect community, you can expect fun, maybe some dancing (hint, hint!). You can definitely expect togetherness when it comes to Black and Brown people and our allies. Were still getting everything fleshed out. At the current moment, however, were excited to see the hype around the Rainbow Village.

Just before we go, are there any last plugs youd like to make for Black in Astro events? Anything else people should be looking for? Where can they keep up with you?

You can find me on all my social media handles (@that_astro_chic). Ill be at AGU this upcoming December in a few weeks, giving a talk based on some of the work Ive done with Black astronomers over the course of my time being an astronomer. And Black in Astro has a dinner that we are having (registration link here), which is hosted by the University of Michigan. Caprice [Phillips, BiA Vice President] has been graciously working on this for such a long time. Im so proud of her for this one. Theres also a session for HBCUs in astronomy that I will also be running at AAS!

A previous version of this article neglected to mention that the Rainbow Village is a collaboration between AAS CSMA, LUMA, BiA, and VanguardSTEM.

Astrobite written by Yoni Brande

Astrobite edited by Keighley Rockliffe

Featured image credit: Black in Astro

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The Rainbow Village at AAS: Ashley Walker and Black in Astro - Astrobites

By Amelia Heymann

Nick Driver came to VCU in 2011 as a freshman majoring in music, but then he was star-struck. An astronomy class taught by Bob Gowdy changed Drivers life, not just his major.

Now a dozen years later, Driver is graduating with his third degree from Virginia Commonwealth University, a doctorate innanosciencein theDepartment of Physicsthat builds on his masters (for whichGowdywas his program advisor) and his undergraduate degree.

It also builds on a fascination dating to his childhood. Driver recalls staying up until 4 a.m. with his mother, gazing at meteor showers and other astronomical wonders through their telescope.

I loved that stuff for a long time, but never thought I was going to do it professionally and physics, he said.

NASA has been an ongoing beneficiary of Drivers talent, which he attributes to VCUs hands-on teaching and experimentally focused approach in the nano program. But beyond the specialized scientific and engineering knowledge he has gained at VCU, communication skills have been a major part of his education.

I could say a whole bunch of, like, specific fancy science stuff, but its better to just be able to talk to people, he said.

During his time in the graduate program, Driver has had three internships at the NASA Goddard Space Flight Center first an in-person internship, followed by two remote internships. Now he is working part time with a group creating nanosensor platforms and quantum dot spectrometers.

Drivers NASA experience stems from a partnership program among universities and the space agency called theCenter for Research and Exploration in Space Science & Technology II.CRESSTII brings students from universities across the Southeast to collaborate on research and instrument development at Goddard.

For all his hard work, he has not only successfully completed his thesis work, but also worked with us on the side while doing classes or taking on other responsibilities, saidMahmooda Sultana, Ph.D., an instrument scientist in the Planetary Environments Lab atGoddard and the principal investigator of the two projects.

Sultana has worked with Driver since his first summer internship, where he made a strong impression. She was excited he wanted to continue working with her team part time.

Currently, Driver is helping develop remote sensing technology. One of the two projects he worked on as an intern with Sultana is a multifunctional nanosensor platform, which consists of multiple sensors on a small chip. Driver said the platform is a way to sense gases, temperature, pressure and other conditions in space environments such as on the International Space Station or on the moon. Nanotechnology is at the heart of these miniaturized in situ chemical analysis instruments.

Driver has been helping the team with data analytics to help improve their data analysis algorithm. Sultana, who is team leader and principal investigator for the projects Driver is supporting, said some of the data analysis algorithms used to take a long time due to a large data set, but Driver has improved the protocol for analysis and shortened the processing time.

He is able to bring in some of his expertise that he has developed in grad school and contribute to both of my projects, Sultana said.

Drivers team has also been working on quantum dot spectrometers, which are nanometer-sized crystals of semiconductors that selectively absorb and emit light. These are often used in TVs and traffic lights, and NASA is developing a special type of spectrometer to investigate the atmosphere of other planetary bodies.

Driver hopes a full-time opportunity at NASA will develop after graduation. And while his current team is small, he loves working in such an intimate group and developing strong friendships.

Its rare to end up working with people that are close-knit like that, because in science, especially NASA, you think about those flagship missions. There could be hundreds of people working to send a rocket up, Driver said. But we get to be kind of these small groups of people just working on one thing every day.

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Class of 2023: Nick Driver changed his tune and, with three VCU degrees, is now shooting for the stars - VCU News

Researchers are looking for an explanation for a problem called the Hubble tension. This is a problem that leaves the question: what is the expansion rate of the Universe? No answer.

The Universe is expanding rapidly. When we observe very distant galaxies we realise that they move away from us quickly. The first person to realise this was astronomer Edwin Hubble in the 1920s. Hubble introduced with observations that the Universe was expanding.

Decades of observations confirmed what Hubble had observed. In the 1990s, the Hubble telescope - named because of the astronomer - was launched with the main objective of answering the question: what is the rate of expansion of the Universe? Or how much is it expanding?

This is a question that to this day brings discussions within the field of Astronomy.This is because each measure gives a slightly different result that can have different consequences. A new study argues that these results differ because we are inside a void in the Universe with low density of galaxies.

The first observation that galaxies further away from us move away more quickly came with the work of Edwin Hubble. This meant that not only was the Universe expanding but also expanding in an accelerated way. A discovery for astronomers of the time who were still dealing with the fact that other galaxies existed.

The rate of expansion of the Universe took the name of Hubble constant, it measures the rate in units of km/s per megaparsec.

The first estimate of the Hubble constant was made by Edwin Hubble himself, who reached a value of 500 km/s per megaparsec. Nowadays, the value is close to 70 km/s per megaparsec despite the divergences of different observation tools.

Before the question of how much the Universe expands, it is more common to ask ourselves why it expands. And that's on the back of a concept called dark energy. Dark energy would be a component of the Universe that has the effect of the expansion we observe.

What dark energy is still remains a mystery. To this day we can only observe the effects it causes and the way it acts against the gravitational interaction that dominates at smaller scales. Many physicists and astronomers seek to answer the question of what dark energy is.

It is important to note that dark energy and dark matter are two different components and are not related in principle. While one acts on smaller scales through gravitational interaction (dark matter) the other has an action on cosmological scales and an opposite effect to that of gravitational interaction (dark energy).

The idea of measuring the Hubble constant seems to be simple: just calculate how far away the galaxies are and measure. However, the reality is a little more complicated. There are different methods to calculate the speed and distance of galaxies from the use of supernovae luminosity to the use of redshift and cosmic background radiation.

All measurements should give equal values but that's not what happens so the question that arises is: which measure is correct and why do the others fail?

In addition, some measures show that the Universe seems to be expanding faster closer to us, which is not true. This raises a problem called the Hubble voltage problem or the Hubble voltage crisis.

A group of researchers from the University of Bonn in Germany proposed an interesting idea to explain Hubble's tension. The group argues that errors in measurements are associated with our position in the Universe because we are in a low density region, in other words, we are more alone than we thought.

The research used observations of groups of galaxies located 600 million light-years from us. These galaxies are moving away faster than expected by the cosmological model, meaning that something else would be pulling them.

The cosmic network of the Universe looks like a spider web where galaxies tend to be attracted to regions with other galaxies through gravitational interaction. This forms a network with filaments with a high density of galaxies and voids with very low density.

The idea of the work is that we are located close to one of these voids and when we look at groups close to us we are seeing them being attracted by these filaments. This would cause the gravitational interaction to pull these galaxies into the filaments moving them away from us who are out of reach.

The study argues that the next observations should be made with this possibility in mind. Add the effect that nearby galaxies are being pulled by other galaxies and this affects the result.

In addition, the group also argues in favor of MOND that it is a modified theory of gravity and that it should be considered in future analyses as well.

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Are we in a hole in the universe? The possible explanation of a problem in astronomy - Yourweather.co.uk

In 1960, Dr. Frank Drake led the first Search for Extraterrestrial Intelligence (SETI) experiment at the National Radio Astronomy Observatory in Green Bank, West Virginia. In the more than sixty years that have since passed, astronomers have conducted multiple surveys in search of technological activity (aka. technosignatures). To date, Breakthrough Listen is the most ambitious SETI experiment, combining data from the Robert C. Byrd Green Bank Telescope, the Parkes Murriyang Telescope, the Automated Planet Finder, and the MeerKAT Radio Telescope and advanced analytics.

The program includes a survey of the one million closest stars to Earth, the center of our galaxy and the entire galactic plane, and the 100 closest galaxies to ours. In a recent paper, members of Breakthrough Listen presented the results of their radio technosignature search of the centers of 97 nearby galaxies observed by the Robert C. Byrd Green Bank Telescope. This search was one of the largest and broadest searches for radio evidence of extraterrestrial intelligence ever undertaken, surveying trillions of stars at four frequency bands. Unfortunately, no compelling candidates were found.

The team was led by Carmen Choza, an Assistant Researcher with the SETI Institute and a Berkeley SETI Research Center Intern with Breakthrough Listen. She was joined by colleagues from Breakthrough Listen and the SETI Institute and researchers from the Institute of Space Sciences and Astronomy at the University of Malta, the International Centre for Radio Astronomy Research (ICRAR) at Curtin University, and the Green Bank Observatory (GBO). The paper that details their findings, The Breakthrough Listen Search for Intelligent Life: Technosignature Search of 97 Nearby Galaxies, recently appeared in The Astronomical Journal.

As they indicate in their study, the experiment by Choza and her colleagues consisted of a narrowband Doppler drift search at four frequencies (1.1-2.7 GHz and 4.0-11.2 GHz) of 97 galaxy centers. These galaxies were part of a previous Breakthrough Listen survey (conducted in 2017) of 123 nearby galaxies that represented a complete sample of morphological types (i.e., spirals, ellipticals, dwarf spherioidals, and irregulars). This approach breaks with most traditional SETI surveys, in that it did not focus on individual stars or setllar clusters. As Choza told Universe Today via email:

When searching for life out there in the Universe, we expect that it would form on planets like it did on ours. Many previous studies have focused on one star at a time, often stars that have known planets around them. The stellar densities we can target by aiming for the galaxy centers means we can search millions of stars, and potentially millions of stellar systems with planets, for the chance at finding a signal.

Galaxies allow us to cast an immense net, with the catch that the signal would need to be more powerful than any signal current human technology could generate. Therefore, targeting galaxies allows us to search for civilizations far more technologically advanced than humankind. Although civilizations capable of producing such a signal might be vanishingly rare, a successful detection would be profoundly hearteningit would mean there is a definitive chance for humankind to gain far greater levels of technology than it now possesses without collapsing.

All data for this experiment was gathered by the 100-meter Green Bank Telescope (GBT) located at the GBO in West Virginia. The team selected the GBT because its backend allows for the storage and analysis of greater volumes of SETI data than was ever before possible. Morever, GBT observations employ a cadence strategy, where targets in the sample are observed for five minutes, and then an offset location is observed several beamwidths from the target. This pattern is repeated three times with three separate offset locations (each of which is observed for 5 minutes), resulting in a 30-minute ABACAD cadence.

Each cadence was then analyzed using the turboSETI pipelines to search for linearly-chirped narrowband Doppler-drifting signals. This search targets narrowband, drifting technosignatures; that is, signals a few Hz wide that show frequency drift, indicating that the transmitter is accelerating relative to the Earth, said Choza. If it drifts, its from elsewhere, whether that means satellites in orbit, Voyager sailing through space far away, or a transmitter on a distant planet. We choose a drift rate of -4 Hz/s to 4 Hz/s to search a range of accelerations one might expect from transmitters located on real exoplanets.

Moreover, the team established constraints on the data to too look for possible transmitters with the equivalent isotropic radiated power of 1026 W or 10,000 zetawatts (ZW)! As Choza explained, this power level was chosen because it corresponds to the theoretical power consumption of a civilization capable of harnessing all the energy of its star system i.e., a Type II Civilization on the Kardashev Scale:

With a well-characterized instrument like the Green Bank Telescope and some assumptions about the signals were searching for, we can calculate the minimum power an isotropic signal that is, a signal broadcasting out in all directions into the universe would have to transmit with in order for us to be able to detect it. For the furthest galaxies in our sample, our search could detect a hypothetical beacon transmitting with power on the order of 1026 Watts similar to the full power output of the Sun. A Kardashev Type II civilization, theorized to be able to capture the full power resources of a host star, could theoretically construct a beacon of sufficient scale to communicate across intergalactic distances.

In the end, the team obtained 1,519 candidate signals that were not attributable to radio frequency interference. Upon algorithmic processing, correlation of signal characteristics with known RFI populations, and extensive visual inspection, they found no compelling evidence of technosignatures. However, this latest survey was groundbreaking in many ways and will have significant implications for SETI research going forward. As Choza explained, its important to maximize the field of view when searching for rare signals and to rigorously account for foreground and background sources:

This survey represents a landmark in the completion of the Breakthrough Listen missions original search goals, and complements searches of nearby individual stars for lower-power transmitters, given that we dont know how numerous or bright extraterrestrial transmitters might be, it also serves as an inflection point in the development of new search methods to improve and re-analyze previous searches. We place the deepest constraints to date on the presence of technosignatures in nearby galaxies.

This paper is the culmination of a years worth of effort and the contributions of many authors to improving Breakthrough Listen methods and driving technosignature science forward towards ever-deeper constraints and ever-greater numbers of star systems. The program has been an amazing way to get young people involved in science, myself included, and some of the most exciting papers coming out of the collaboration are spearheaded by graduate students, postbacs, or interns!

These results could also help inform future searches by Breakthrough Listen, including the planned observations of our own galactic center, a sample of nearly two thousand nearby stars, and another sample of galaxies observable from the Southern hemisphere using the Parkes Murriyang Telescope.

Further Reading: arXiv

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Breakthrough Listen Scans Entire Galaxies for Signals From Extremely Advanced Civilizations - Universe Today

MAUNA KEA: Shane Palacat-Nelsen's voice drops to a reverent tone as he tells the story of the snow goddess Poliahu who Native Hawaiians believe inhabits the summit of Mauna Kea , the highest point in Hawaii . The tale, repeated in Hawaiian families over generations, speaks of a chief who yearned to court Poliahu but was stopped by her attendants guarding the sacred mountain top - the abode of the gods, cradle of creation and gateway to the divine. Today, this sublime summit on Hawaii's Big Island is also treasured by astronomers as a portal to finding answers to the universe's many mysteries, creating varied - and sometimes incompatible - views on what's best for Mauna Kea's future. The legendary chief eventually gained access to the summit on one condition: He was to step only on the same set of footprints left by the attendant escorting him up and down, said Palacat-Nelsen. He says it's a metaphor for why Mauna Kea must be protected from further human intrusion, pollution, and erosion. "You do not go up the sacred mountain unless you are called. You do not go up without a purpose." Mauna Kea is a dormant 14,000-foot shield volcano . In Native Hawaiian lore, it is the first-born son of the sky father and earth mother. The mountain's dry atmosphere and limited light pollution make for a perfect location to study the skies - one of just a handful on the planet. Over the past 50 years, astronomers have mounted a dozen giant telescopes on the summit, with several yielding exalted discoveries, like proving the Milky Way has a supermassive black hole at its center. That particular research led to a Nobel Prize in Physics in 2020. The proliferation of observatories has troubled many Native Hawaiians, who have pushed back. In their view, such construction is polluting the sacred mountain top, eroding the environment and depleting natural resources. In 2019, thousands came out to protest a proposed $2.65-billion Thirty Meter Telescope project near the summit. This protest catalyzed the passage of a new state law transferring jurisdiction of the mountain to a new stewardship authority comprising scientists and Native Hawaiian cultural practitioners. No side wants to reduce this debate to a culture-versus-science conflict because Hawaiian spirituality embraces science, or studying the physical world, and many astronomers respect Hawaiian culture. Some observatory staff and cultural practitioners are taking small, tentative steps toward new dialogue, but overcoming the cavernous divide will involve difficult conversations and understanding different perspectives. Mauna Kea, translated literally as "white mountain," has the same progenitors - Wakea and Papahanaumoku - as the Hawaiian people, according to stories, prayers and chants. After volcanic eruptions sent lava bubbling up from the ocean floor, it took more than a million years to form, growing into the tallest mountain on Earth when measured from its base in the Pacific Ocean. The summit soars 13,796 feet (4,205 meters) above sea level, evoking an ethereal feeling as fluffy clouds swaddle its cinder cones and blanket its reddish, almost Mars-like soil. On a clear day, Mauna Loa, one of the world's most active volcanoes, is visible. Climbing Mauna Kea is like peeling the layers of an onion, says Kealoha Pisciotta, a cultural practitioner and longtime activist. The sacred mountain's slopes are dotted with ceremonial platforms, ancestral burial sites and Hawaii's lone alpine lake, whose waters are believed to possess healing properties. "The higher you go, the closer your heart is to the heavens," she says. "(The gods) can see you, feel you, hear you. The protocol is silence because we don't need to be speaking in akua's (creator's) house. We need to be listening." Building and bulldozing on or near the summit threatens the people's sacred connection to the land, Pisciotta said. In her spiritual practice, she considers the mountain and all aspects of creation such as fish, coral, trees and animals to be like older siblings. "When they diminish our ancestors and our elder siblings, they diminish us, our life force and our existence. And that's the reason people are saying no," she said, referring to adding more telescopes. Palacat-Nelsen, who served on the working group that laid the foundation for the new authority, says to protect the mountain and preserve the summit's sacredness, people must step out of their silos with open hearts and minds, ready to have uncomfortable conversations. John O'Meara, who moved to Hawaii to become the chief scientist at Keck shortly before the 2019 protest, is now a key player in that dialogue. He's learning about the strong connection many Native Hawaiians have to Mauna Kea. O'Meara is fascinated by the similarities between spirituality and astronomy. "We are fundamentally asking the same questions, which are: Where are we? Where did we come from? And where are we going? There is a deep connection to the universe...which is the thing that we should be focusing on," he said. Doug Simons, director of the University of Hawaii's Institute for Astronomy, points to the opening lines of the Kumulipo, a centuries-old Hawaiian creation chant, which describes a scene strikingly similar to what astronomers believe existed during the Big Bang. "When fundamental space altered through heat/When the cosmos altered, turning inside out," begins the chant, according to a translation by Larry Kimura, a Hawaiian language expert. It continues a few lines later: "Then began the slime that established a physical space/The source of impenetrable darkness, so profound/The source of fathomless power, reincarnating itself." The chant continues for 2,000 more lines, detailing the birth of coral, seaweed, fish, trees and, eventually, people. The Kumulipo's description of a dark, eternal form of energy from which everything emerges sounds to Simons like dark energy, which astronomers believe predated the universe. Scientists can observe dark energy, which is causing the universe to expand at an accelerated rate, by studying dark matter - invisible to the naked eye, but detectable through the study of distortions in galaxy shapes. Mauna Kea's telescopes are at the forefront of discoveries about this dark energy thanks to their "exquisite image quality," Simons said. Lanakila Mangauil, a Native Hawaiian spiritual practitioner, was around 9 when he first stepped on the mountain for snow play at the lower elevations. His family never went to the summit. "One of the important spiritual practices on Mauna Kea is our absence," he said. "We stay off it because it is sacred." When he first ascended the mountain for ceremony, he was a high school senior and climbed with two of his friends. They stopped at altars, prayed near the upper cinder cones, offered chants and dance. Mangauil does not like to use the word "religion" to describe his spiritual practice. Hawaiians don't have a central religion, he said, but spiritual practices born of different communities, families and environments. "Our spiritual practice is not faith-based, it is knowledge-based," he said. "Our gods and goddesses are scientific observations." For example, to understand the deities of Mauna Kea is to understand the mountain's environment and climate, Mangauil said. Poliahu is the snow goddess, sister of Pele, the goddess of volcanoes and denizen of neighboring Mauna Loa. Lilinoe is the goddess of fine mist. Waiau presides over the mountain's subterranean reservoirs. Lake Waiau, associated with the god Kane, is where some Native Hawaiians bury their children's umbilical cords. Its water is collected and used for healing and ceremonies. The summer solstice is an important ritual Mangauil observes on Mauna Kea as is a Makahiki ceremony in the fall, which marks the start of the Hawaiian new year. This is also a political and cultural issue for younger Hawaiians like Mangauil who considers himself a product of the Hawaiian Renaissance. Prior generations lost their language as well as culture and religious practices after the US-backed overthrow of the monarchy in 1893. "We are reestablishing our spiritual relationship with the land, which was disrupted by colonization." Not all Native Hawaiians hold Mauna Kea sacred in a religious sense, including Makana Silva, an astronomer who grew up on Oahu and was raised Catholic. He is now a post-doctoral fellow at the Los Alamos National Laboratory in New Mexico studying black holes and gravitational waves, and visited Mauna Kea's summit for the first time three years ago. Despite his personal religious beliefs, he is certain that the mountain contains what Hawaiians call "mana" - the spiritual life force that permeates the universe. Silva described a moment when he and his friend stood by Lake Waiau "in peace, silence and awe." He believes astronomy on the mountain should thrive so there is a place for Hawaiians to perpetuate their legacy of innovation. "We have a responsibility to future generations to leave behind these new inventions so they can go places you and I have never been able to dream of," Silva said. The future of astronomy on the mountain will in large part be decided by the Mauna Kea Stewardship and Oversight Authority, which is taking over managing the mountain from the University of Hawaii. It will determine whether to renew the university's 65-year lease for the summit lands, which is due to expire in 2033, and subleases for lands used by all the mountain's telescopes. Simons is concerned about the consequences if the leases aren't renewed in time. The existing master lease says the telescopes must be dismantled and the land under them restored to their original states by 2033 if the lease is not renewed. "The potential loss of Mauna Kea astronomy...would be catastrophic," Simons said, adding that this would mean a tremendous loss of knowledge and opportunities for Hawaii's budding astronomers. Palacat-Nelsen doesn't believe astronomy on the summit will end any time soon. But he does see the lease being renewed at a much higher price than the $1 a year the University of Hawaii pays now. "You have to pay the best price for the best view," he said. He holds out hope for better understanding between the two communities. He recently invited a handful of Keck astronomers and officials to his family's "heiau" or place of worship on Big Island. Rich Matsuda, Keck's interim director and an engineer, was part of that group. He said the experience shed light on the extensive preparation required to enter a sacred space, such as leaving one's everyday troubles and anxieties outside, which can be challenging. He has since followed similar protocols when traveling to the summit and believes they could be shared more broadly with other telescope workers. Palacat-Nelsen said such efforts by observatories give him hope that people will become more mindful of their footprints on Mauna Kea, like the legendary chief who visited the snow goddess. Palacat-Nelsen is grateful to his ancestors for preserving and maintaining Mauna Kea so current generations have the opportunity to experience the divine. He wonders if he can do that for posterity. "Can they speak about me in that way 200 years from now?" he asks. "I hope."

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A volcano on Hawaii's Big Island is sacred to spiritual practitioners and treasured by astronomers - IndiaTimes

In June, scientists presented compelling evidence that they discovered a massive "hum" of low-frequency gravitational wavesrippling through the universe.

Similar to the ripple effect that occurs when a stone is thrown into the water, a similar phenomenon happens in space. Instead of creating waves that can be seen by the human eye or optical telescopes, the shockwaves that are produced from gravitational energy merging are called gravitational waves.

Physicist Albert Einstein first theorized about the existence of gravitational waves in 1916. But it wasn't until 2015, when the Laser Interferometry Gravitational-Wave Observatory (LIGO) made its first detection of gravitational waves in the universe, that scientists were able to confirm their existence. Since then, the discovery of gravitational waves have allowed scientists to peer inside neutron stars and discover the wobbliest black hole ever detected.

In June, the researchers posited that the massive hum they found was coming from the merging of two supermassive black holes, a type of explosive collision almost too big and too powerful to imagine. But as Salon reported at the time, that wasnt the only candidate as a source.

"We found the choir, but we don't know who's singing in it the pop stars are the supermassive black holes, they're the ones that are the most obvious candidates," NANOGrav scientist Chiara Mingarelli told Salon in June. "However, there are other potential sources of gravitational waves, like quantum fluctuations in the early universe that were driven to the size of the whole universe by inflation."

"We found the choir, but we don't know who's singing in it."

The mission to figure out the source is an international one, as scientists gather data and put it together in an attempt to construct an atlas of this background hum. In an email to Salon, Kai Schmitz, a cosmologist who is part of the international search, said scientists have been sharpening their tools and analyses further. While they dont expect a next round of data sets to be available for another few months and / or years, "primordial gravitational waves from inflation" remains a viable option as a source, Schmitz said.

Taking a step back, Schmitz explained that the possibility that the hum is coming from the merging of two supermassive black holes got the most attention because its the most realistic option. We know that supermassive black holes exist, he said. Most galaxies have supermassive black holes at their center.

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So, it's easy to imagine that when two galaxies merge, each with a supermassive black hole at its center, we ultimately end up with one big galaxy that hosts a pair of supermassive black holes at its center, he said, adding that a possibility like primordial gravitational waves from inflation is more speculative.

Whenever we speculate about gravitational waves from the Big Bang, we need to assume new physics [for example] new interactions, new particles, new forces that go beyond the Standard Model of particle physics, he said. One such scenario of new physics is cosmic inflation, which denotes a stage of exponentially fast expansion in the early Universe.

In other words, the theory of cosmic inflation suggests that right before the Big Bang, a faster-than-light expansion of the universe occurred in the fraction of a second. The rapid expansion occurred due to an unknown source of energy and could be the cause behind the Big Bang.

Whenever we speculate about gravitational waves from the Big Bang, we need to assume new physics."

Recall that gravitational waves are exactly that: ripples in spacetime, perturbations of the fabric of space and time, that stretch and squeeze distances between objects floating through spacetime,Schmitz said. So, the primordial quantum mechanical vacuum fluctuations of the spacetime that are stretched to cosmological sizes during inflation continue to propagate through the Universe in the form of drum roll gravitational waves.

Basically, these waves could be the sounds of the universe forever growing and reproducing. According to the cosmic inflation theory, the universe is eternal, leading to the speculative theory of pocket universes, which would mean that the universe is forever growing and reproducing. Our universe is just one pocket in this.

Another possible explanation is that the hum is also coming from cosmic strings, which are remnants from the early universe when it cooled down quickly and left cracks that are floating around in space. This could mean that we live in a cyclic ekpyrotic model, in which there is no beginning or end of the universe.

However, in order for theorists to find evidence for this theyre going to have to work extra hard.

The standard picture of simple vacuum fluctuations of the spacetime metric will result in a signal that's too weak, Schmitz said. Instead, more complicated processes need to be at work during inflation in order to source a sufficiently strong gravitational-wave signal.

But that doesnt mean its not possible. And Schmitz has some ideas on how to proceed.

Primordial gravitational waves from inflation may lead to an appreciable contribution to the energy density of dark radiation in the early Universe, which is a prediction that can be tested in future observations of the cosmic microwave background and measurements related to Big Bang nucleosynthesis, he said. In other words, the more we study that massive explosions that set our universe in motion, the better we can understand how it came humming along.

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Astronomers search for sources of mind-bending gravitational hum permeating the universe - Salon