Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomy podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky. This week in Astronomy, NASA's
Speaker 1: SPHEREx tracking objects through sound and blazing light from cosmic darkness.
Speaker 1: NASA's SPHEREx begins mapping the invisible universe. NASA's SPHEREx mission
Speaker 1: has officially begun its groundbreaking scientific observations, initiating an ambitious
Speaker 1: effort to map the entire sky in unprecedented detail. Launched
Speaker 1: on March eleventh, the spacecraft spent the first six weeks
Speaker 1: in space undergoing a series of checkouts, calibrations, and system verifications.
Speaker 1: These preparations ensured that SPHEREx, a space based observatory designed
Speaker 1: to observe an infrared light invisible to the human eye,
Speaker 1: would be ready to fulfill its mission to scan the
Speaker 1: cosmos in one hundred and two different infrared wavelengths, producing
Speaker 1: a comprehensive three D map of hundreds of millions of
Speaker 1: galaxies and providing new insights into the origins of the universe,
Speaker 1: the structure of galaxies, and the chemical building blocks of
Speaker 1: life in the Milky Way. As of May first, SPHEREx
Speaker 1: has entered its phase of regular science operations. Over the
Speaker 1: next two years, it is scheduled to take approximately three thousand,
Speaker 1: six hundred images each day, culminating in a vast, digitally
Speaker 1: woven mosaic of the entire sky. This ambitious project will
Speaker 1: produce four complete sky maps during its primary mission, capturing
Speaker 1: cosmic features and structures in exquisite detail. SPHEREx orbits Earth
Speaker 1: about fourteen and a half times a day in a
Speaker 1: polar orara, traveling from north to south and passing over
Speaker 1: both poles. This configuration allows it to systematically cover circular
Speaker 1: strips of the sky each day, and as Earth journeys
Speaker 1: around the Sun, Spherex's vantage point gradually shifts, enabling it
Speaker 1: to view the universe in every direction. Over the course
Speaker 1: of six months. The observatory gathers data using six infrared
Speaker 1: detectors that capture different wavelengths simultaneously, producing what are known
Speaker 1: as exposures. About six hundred per day. Each exposure consists
Speaker 1: of six unique images, and together they represent a spectrum
Speaker 1: of invisible light that holds critical information about the distant
Speaker 1: objects being observed. Instead of traditional thrusters, SPHEREx adjusts its
Speaker 1: orientation using internal reaction wheels, allowing it to shift its
Speaker 1: entire body between exposures with precision and efficiency. One of
Speaker 1: the most striking features of SPHEREx is its ability to
Speaker 1: observe the sky in one one hundred and two colors
Speaker 1: of infrared light, a feat that has never been accomplished before.
Speaker 1: Unlike visible light, infrared light can pass through cosmic dust
Speaker 1: and reveal phenomena that would otherwise remain hidden. This capability
Speaker 1: allows SPHEREx to see into dusty regions of space, like
Speaker 1: the dense interstellar clouds where stars and planetary systems form.
Speaker 1: A striking early image from the telescope, taken at a
Speaker 1: wavelength of three point twenty nine microns, reveals a dusty
Speaker 1: cloud composed of molecules akin to soot or smoke, structures
Speaker 1: that are both visually stunning and scientifically valuable. Spherrex uses
Speaker 1: a method called spectroscopy to analyze the light it collects.
Speaker 1: This technique splits light into its component wavelengths, similar to
Speaker 1: how a prism creates a rainbow. With spectroscopy, scientists can
Speaker 1: determine how far away a galaxy is, allowing them to
Speaker 1: assemble a three dimensional cosmic map instead of a flat,
Speaker 1: tutementional one. This depth of information helps researchers trace the
Speaker 1: expansion history of the universe and uncover the distribution of
Speaker 1: matter on the largest scales. One of the mission's most
Speaker 1: compelling goals is to shed light on cosmic inflation, or
Speaker 1: rapid expansion, that occurred in the first fraction of a
Speaker 1: second after the Big Bang. During this phase, the universe
Speaker 1: expanded faster than the speed of light, going from subatomic
Speaker 1: to cosmological scales in an instant. This dramatic event left
Speaker 1: subtle imprints in the distribution of galaxies, and Spherrex's vast
Speaker 1: sky maps are expected to reveal patterns that will help
Speaker 1: scientists decode this primordial mystery. By observing the largest scales
Speaker 1: of the modern universe, scientists hope to infer what happened
Speaker 1: at the smallest scales during its earliest moments. A poetic
Speaker 1: symmetry between the ancient and the vast beyond exploring the
Speaker 1: origins of the cosmos. Spherrex also investigates the ingredients for
Speaker 1: life within than our own galaxy by analyzing the light
Speaker 1: from interstellar clouds. The mission aims to identify water and
Speaker 1: other essential compounds across a wide range of environments in
Speaker 1: the Milky Way. It is believed that the water found
Speaker 1: on Earth may have originated as frozen molecules on cosmic
Speaker 1: dust grains in the same interstellar cloud that birth the
Speaker 1: Sun's SPHEREx will perform over nine million such observations, allowing
Speaker 1: scientists to study how the chemistry of these materials changes
Speaker 1: with varying conditions, and leading to a better understanding of
Speaker 1: the origins of planetary systems and life friendly environments. SPHEREx
Speaker 1: does not operate in isolation. It is part of a
Speaker 1: broader strategy by NASA to understand the universe, complementing missions
Speaker 1: like the upcoming Nancy Grace Roman Space Telescope. Together, these
Speaker 1: observatories form a coordinated campaign to address some of the
Speaker 1: deepest questions in astrophysics, from the fundamental forces that shape
Speaker 1: the universe to the process is that foster life. In
Speaker 1: its many corners, the mission represents more than a technological milestone.
Speaker 1: It's a fulfillment of over a decade of dedication from
Speaker 1: teams across NASA, academia, and industry. The instrument has performed
Speaker 1: exactly as hoped, meeting expectations with precision and opening the
Speaker 1: door to discoveries both anticipated and unforeseen. Scientists and engineers
Speaker 1: who have long worked toward this goal now watches SPHERICX
Speaker 1: begins to deliver on its promise to illuminate the hidden universe,
Speaker 1: transform our cosmic perspective, and perhaps uncover answers to some
Speaker 1: of the most profound questions about where we come from,
Speaker 1: what we are made of, and how the universe came
Speaker 1: to be. As it is tracking space objects through sound,
Speaker 1: space debris and meteoroids are constantly making their way toward Earth,
Speaker 1: creating a persistent and increasingly significant hazard as they streak
Speaker 1: through the atmosphere at high speeds. Among the tools scientists
Speaker 1: used to monitor these high velocity entries are infrasound sensors,
Speaker 1: special instruments that detect extremely low frequency sounds that human
Speaker 1: errs cannot hear. These sensors have become vital in detecting
Speaker 1: the acoustic signatures of bolides, which are meteoroids that explode
Speaker 1: or fragment dramatically in the sky, releasing large amounts of
Speaker 1: energy that ripple through the atmosphere as infrasound waves. However,
Speaker 1: tracking these events accurately involves more than just picking up
Speaker 1: their sound. A new study has demonstrated the importance of
Speaker 1: factoring in the object's trajectory, especially when it enters Earth's
Speaker 1: atmosphere at a shallow angle. Each year, Earth collects a
Speaker 1: surprising amount of material from space. Thousands of metric tons
Speaker 1: of space dost drift down from the Cosmos, and around
Speaker 1: fifty tons of meteorites crash into the surface annually. Since
Speaker 1: the beginning of the space Age, humanity has added to
Speaker 1: this influx with its own debris space jump, including rocket remnants,
Speaker 1: lost astronaut tools, and decommissioned satellites, hovers in low Earth
Speaker 1: orbit at astonishing speeds, often reaching up to eighteen thousand
Speaker 1: miles per hour. Occasionally, some of these objects return to
Speaker 1: Earth their fiery descent, creating a risk not only to
Speaker 1: technology and infrastructure, but also to human life. However small
Speaker 1: a chance may be when any space object re enters
Speaker 1: the atmosphere, whether a natural meteoroid or a piece of
Speaker 1: artificial debris. Scientists rush to track its trajectory. They need
Speaker 1: to determine not only when and where it will land,
Speaker 1: but also how it will travel through the atmosphere. Some
Speaker 1: may plunge directly downward, while others streak across the sky
Speaker 1: at shallow angles, skimming the atmosphere before coming to rest.
Speaker 1: Understanding this path is crucial for accurate predictions and potentially
Speaker 1: for issuing alerts or planning responses in the rare event
Speaker 1: of a dangerous impact. This challenge has drawn attention from
Speaker 1: researchers like Elizabeth Silber at Sandy and National Laboratories, who
Speaker 1: is presenting our findings at the European Geoscience's Union General Assembly.
Speaker 1: She focuses on how infrasound sensors detect bulllides and how
Speaker 1: their readings are influenced by the angle at which these
Speaker 1: objects enter the atmosphere. Bulllides are not static events. They
Speaker 1: are dynamic, fast moving phenomena. As they barrel through the sky,
Speaker 1: they generate infrasound along their flight path rather than from
Speaker 1: a single stationary point. This creates a sonic footprint more
Speaker 1: like a sweeping boom than a single explosion. In cases
Speaker 1: where the bullid enters steeply at angles greater than sixty degrees,
Speaker 1: the analysis of infrasound signals can reliably reconstruct the trajectory,
Speaker 1: but when these objects enter more horizontally, the signals become
Speaker 1: more complex and harder to interpret. The sound travels across
Speaker 1: longer distances and is picked up from multiple directions by
Speaker 1: different infrasound stations, increasing the uncertainty and determining exactly where
Speaker 1: the object was and where it might land. To dig
Speaker 1: deeper into this problem, Silber used data from a global
Speaker 1: network of infrasound sensors operated by the Comprehensive Test Ban
Speaker 1: Treaty Organization. Although this network is primarily designed to detect
Speaker 1: illicit nuclear tests, it also captures many other loud atmospheric events,
Speaker 1: from lightning to rocket launches. By focusing on bull eyed events,
Speaker 1: Silber was able to isolate the geometric elements of the
Speaker 1: infrasound data, specifically how the movement of the object affected
Speaker 1: the sound's propagation. Her finding stress that trajectory must be
Speaker 1: accounted for if scientists are to interpret the signals correctly,
Speaker 1: particularly for objects with flatter paths. This research underscores a
Speaker 1: larger point about planetary defense and the management of space
Speaker 1: debris Infrasound sensors are an essential part of the global
Speaker 1: toolkit for tracking threats from aboff. However, their effectiveness depends
Speaker 1: on how well we understand and interpret the data they collect.
Speaker 1: If the direction and speed of an incoming object are
Speaker 1: not accurately reconstructed, it becomes much harder to predict its
Speaker 1: landing site or assess the risks. In short, knowing that
Speaker 1: something is coming is not enough. Scientists need to know
Speaker 1: how it's moving in order to respond effectively. This work
Speaker 1: not only advances our ability to monitor meteoroids, but also
Speaker 1: has important implications for the safe management of space junk
Speaker 1: as our skies become increasingly crowded. Blazing light from cosmic darkness.
Speaker 1: Some of the brightest sources of light in the universe
Speaker 1: have their origins in some of the darkest places imaginable,
Speaker 1: the regions surrounding supermassive black holes at the centers of galaxies.
Speaker 1: These brilliant cosmic beacons, which we cannot see with the
Speaker 1: naked eye, emit immense amounts of energy across the electromagnetic spectrum. Satellites,
Speaker 1: particularly NASA's Fermi Gamma Ray Space Telescope have revealed the
Speaker 1: astonishing number and variety of these luminous powerhouses since it
Speaker 1: began its mission in two thousand and eight. Despite their
Speaker 1: association with darkness, black holes helped create some of the
Speaker 1: most powerful light shows in the universe. Fermi's Large Area
Speaker 1: Telescope LAT has cataloged thousands of high energy sources in
Speaker 1: just a single year of observation. Data show hundreds of
Speaker 1: objects flaring and fading in gamma rays, captured in an
Speaker 1: animation where each object's brightness is indicated by the size
Speaker 1: of a glowing magenta circle. The Sun's path is tracked
Speaker 1: two represented by a yellow circle, tracing its annual motion
Speaker 1: across the sky. Over ninety percent of these flashing gamma
Speaker 1: ray sources are what astronomers call blazers, a specific type
Speaker 1: of galaxy powered by supermassive black holes. Supermassive black holes
Speaker 1: are not rare. They lurk at the center of nearly
Speaker 1: every large galaxy, including our own Milky Way. These giants
Speaker 1: range in mass from hundreds of thousands to billions of
Speaker 1: times that of our Sun. While black holes themselves do
Speaker 1: not emit light, they are, after all defined by their
Speaker 1: ability to trap even light what surrounds them. In active
Speaker 1: galaxies can shine intensely. In galaxies with active galactic nuclei
Speaker 1: agn the black hole is surrounded by a dense, swirling
Speaker 1: cloud of gas and dust. As this material spirals inward,
Speaker 1: pulled by gravity, it forms a hot accretion disc. The
Speaker 1: friction and extreme gravitational forces that work heat the disk
Speaker 1: to incredible temperatures, causing it to emit radiation across a
Speaker 1: wide range of wavelengths, from radio waves to X rays
Speaker 1: and gamma rays. This radiation is not the end of
Speaker 1: the story. In about one in ten active galaxies, jets
Speaker 1: of particles are also formed and blasted outward from the
Speaker 1: region near the black hole. These jets travel at speeds
Speaker 1: approaching that of light and extend far beyond the galaxy itself.
Speaker 1: Scientists continue to investigate how black holes, with their overwhelming
Speaker 1: gravity that pulls everything inward, are able to power such
Speaker 1: outward moving high energy jets. The process remains one of
Speaker 1: the more mysterious aspects of black hole physics. The appearance
Speaker 1: and classification of these active galaxies depend heavily on their
Speaker 1: orientation relative to Earth. When we see the jets side on,
Speaker 1: we might classify the galaxy as a radio galaxy since
Speaker 1: the side view reveals strong emissions at radio wavelengths, but
Speaker 1: when the jet is aimed almost directly at us, we
Speaker 1: see a blazer, a galaxy that appears especially bright and
Speaker 1: variable due to the relativistic beaming of light coming from
Speaker 1: its jet. These are the most commonly detected gamma ray
Speaker 1: so in the sky by Fermi. Gamma rays, the most
Speaker 1: energetic form of light, are crucial for astronomers trying to
Speaker 1: understand high energy processes in the universe. They offer insight
Speaker 1: into how particles are accelerated in these extreme environments and
Speaker 1: how they interact with magnetic fields and surrounding material. Since
Speaker 1: two thousand and eight, FERMI has identified thousands of gamma
Speaker 1: ray sources, with blazers making up more than half. Each
Speaker 1: detection adds to the growing picture of the high energy
Speaker 1: universe and the role that AGN play in it. Understanding
Speaker 1: AGN is more than just studying interesting cosmic phenomena. Many
Speaker 1: of these active galaxies formed early in the history of
Speaker 1: the universe. Because of their immense power, they likely played
Speaker 1: a significant role in shaping their environments, influencing the formation
Speaker 1: of galaxies and the evolution of cosmic structures. By studying
Speaker 1: agn scientists hope to uncover the mechanisms that helped shape
Speaker 1: the universe as we know it today. The story of
Speaker 1: the brightest lights in the cosmos is in fact a
Speaker 1: story about how darkness supermassive black holes can generate energy
Speaker 1: on unimaginable scales, revealing the dynamic and ever evolving nature
Speaker 1: of the universe to a