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, black
Speaker 1: hole jets, giant molecular cloud and protoplanetary discs. Unveiling black
Speaker 1: hole jets. The study of relativistic jets originating from supermassive
Speaker 1: black holes is a crucial aspect of astrophysics, as these
Speaker 1: jets play a significant role in shaping their surrounding environments.
Speaker 1: An international team of researchers took a major step in
Speaker 1: this direction by utilizing multi wave length observations of active
Speaker 1: galactic nuclei to explore how black holes launched these powerful jets.
Speaker 1: Sixteen sources were observed with the event Horizon telescope during
Speaker 1: its first observational campaign in twenty seventeen, providing an unprecedented
Speaker 1: opportunity to study jets closer to the black holes than
Speaker 1: ever before. The Event Horizon telescope, an array of globally
Speaker 1: distributed radio telescopes achieves extreme angular resolution by combining signals
Speaker 1: from different locations, effectively forming a telescope the size of Earth.
Speaker 1: This level of detail allows scientists to investigate the mechanisms
Speaker 1: that accelerate and magnetize jets as they emerge from the
Speaker 1: immediate vicinity of supermassive black holes. The research team, led
Speaker 1: by scientists from the Max Planck Institute for Radio Astronomy
Speaker 1: in Bond, Germany in the Institute of Astrophism Physics of
Speaker 1: Andalusia in Grenada, Spain, recently published their findings in the
Speaker 1: journal Astronomy and Astrophysics. To test how well the current
Speaker 1: theoretical models described the evolution of jets in active galaxies,
Speaker 1: the researchers compared observations from the event Horizon telescope with
Speaker 1: past studies conducted using the Very Long Baseline Array in
Speaker 1: the Global Millimeter VLBIRA. These latter facilities operate on larger
Speaker 1: spatial scales, providing a more extensive view of the jets
Speaker 1: development over time. This comparative approach allowed scientists to trace
Speaker 1: how the jets evolved from their origins near the black
Speaker 1: hole to vast distances spanning multiple light years into interstellar space.
Speaker 1: The results revealed an intriguing trend. The brightness temperature of
Speaker 1: the jets, which measures the intensity of radiation emitted from
Speaker 1: a given region, generally increases as the jet plasma moves
Speaker 1: farther away from the black hole. This finding challenge has
Speaker 1: long held assumptions about how these jets behave. Traditionally, it
Speaker 1: was believed that jets follow a conical structure, with plasma
Speaker 1: moving at a constant velocity, while the strength of the
Speaker 1: magnetic field and the density of the jet plasma gradually
Speaker 1: decrease with distance from the black hole. However, the new
Speaker 1: observations suggest a more complex picture. Jets are often assumed
Speaker 1: to be smooth and conical, but the research indicates that
Speaker 1: this model may not accurately describe all cases. The internal
Speaker 1: structure of jets appears to be intricate, with some showing
Speaker 1: signs of acceleration. This could mean that either the plasma
Speaker 1: itself is gaining velocity, or that an observational effect caused
Speaker 1: by a bending jet makes it appear as if it
Speaker 1: is moving faster than it actually is. In some cases,
Speaker 1: when a jet shifts direction and aligns more closely with
Speaker 1: Earth's line of sight, it can create the illusion of
Speaker 1: an increase in speed. By examining a sample of sixteen
Speaker 1: active galactic nuclei instead of just individual sources, the researchers
Speaker 1: were able to minimize the influence of unique characteristics specific
Speaker 1: to any single jet. This broader approach provided a clearer
Speaker 1: picture of jet behavior, revealing that brightness tends to increase
Speaker 1: with distance from the black hole, a strong indication that
Speaker 1: acceleration is taking place. These findings suggest that the mechanisms
Speaker 1: behind jet evolution are more dynamic than previously thought. The
Speaker 1: importance of intermediate scale observations in this study was highlighted
Speaker 1: by Eduardo Ross from the Max Plank Institute for Radio Astronomy,
Speaker 1: who also serves as the European scheduler of the Global
Speaker 1: Millimeter vl. The Global Millimeter VLBIRA, which operates at a
Speaker 1: wavelength of three point five millimeters, provides critical information that
Speaker 1: bridges the gap between the highest resolutions of the event
Speaker 1: horizon telescope and the larger scale views of the very
Speaker 1: long baseline array. This was particularly evident in observations of
Speaker 1: the eight seven galaxy, which played a central role in
Speaker 1: the event Horizon Telescope's first major discoveries active galactic nuclei.
Speaker 1: The luminous centers of certain galaxies are powered by supermassive
Speaker 1: black holes, and some of these objects generate relativistic plasma
Speaker 1: jets that extend thousands of light years into intergalactic space.
Speaker 1: Understanding the physics behind these jets requires observations with extreme
Speaker 1: angular resolution, enabling astronomers to examine their origins in detail. Telescope,
Speaker 1: operated by a global network of scientists, provides this capability.
Speaker 1: In twenty seventeen, alongside its groundbreaking observations of the Milky Way,
Speaker 1: Sagittarius A and eight seven S black hole, the telescope
Speaker 1: also observed several active galactic nuclei to further investigate the
Speaker 1: behavior of jets. To assess the reliability of existing models
Speaker 1: describing jet evolution, the researchers compared the Event Horizon Telescope's
Speaker 1: data with previous studies that had mapped the same sources
Speaker 1: on larger spatial scales. This approach enabled them to trace
Speaker 1: jet development from their launch points near the black hole
Speaker 1: to the vast distances they reach an interstellar space. The
Speaker 1: results indicated that as the jet plasma moves farther from
Speaker 1: the black hole, its radiation power per solid angle, known
Speaker 1: as brightness temperature, tends to increase. This discovery contradicts the
Speaker 1: standard model of jets, which assumes a conical geometry and
Speaker 1: a constant velocity for the plasma. Instead, the new observations
Speaker 1: suggest that some jets exhibit acceleration, a phenomenon that may
Speaker 1: be linked to the role of magnetic fields, changes in
Speaker 1: jet structure, or interactions with the surrounding environment. The exact
Speaker 1: nature of this acceleration remains an open question, requiring further
Speaker 1: studies to fully understand the underlying mechanisms. Future research will
Speaker 1: focus on refining models of jet acceleration, the flow of
Speaker 1: energy within jets, and the role of magnetic fields and
Speaker 1: shaping their dynamics. The ongoing expansion of the Event Horizon
Speaker 1: telescope array will play a crucial role in these efforts,
Speaker 1: providing even more detailed observations of these fascinating cosmic structures.
Speaker 1: Jan Rotor, who led the study, emphasized that additional investigations
Speaker 1: are needed to fully grasp the physics of jet formation
Speaker 1: and evolution. J Antonsensis, director of the Max Planck Institute
Speaker 1: for radio astronomy, and a founding chair of the Event
Speaker 1: Horizon Telescope collaboration, highlighted the significance of these findings. The
Speaker 1: study demonstrates the importance of international partnerships, advanced observational techniques,
Speaker 1: and persistent scientific inquiry in advancing our understanding of the universe.
Speaker 1: With upcoming improvements in telescope technology and the next generation
Speaker 1: of observational networks, scientists will continue to explore the complexities
Speaker 1: of black holed jets, uncovering new insights into one of
Speaker 1: the most energetic and mysterious processes in astrophysics. Giant molecular
Speaker 1: cloud found in Milky Way. Astronomers using the Green Bank
Speaker 1: Telescope GBT have identified a massive new giant molecular cloud
Speaker 1: GMC within the Milky Way Galaxy, expanding our understanding of
Speaker 1: the interstellar medium and star formation. This newly discovered cloud
Speaker 1: MAINEM four section seven to zero point eight, extends nearly
Speaker 1: two hundred light years and holds an estimated mass of
Speaker 1: approximately one hundred and sixty thousand times that of the Sun.
Speaker 1: This finding provides valuable insight into the complex processes governing
Speaker 1: the flow of matter in our galaxy. In the birth
Speaker 1: of stars. Giant molecular clouds are vast reservoirs of interstellar
Speaker 1: gas and dust composed primarily of molecular hydrogen. These clouds
Speaker 1: are essential to the galactic ecosystem, serving as the primary
Speaker 1: sites for star formation. GMCs very widely in size, typically
Speaker 1: spanning between fifteen and six hundred light years, and represent
Speaker 1: the densest and coldest regions of the interstellar medium. Because
Speaker 1: they contain the raw material for star formation, studying their structure, movement,
Speaker 1: and composition is fundamental to understanding how galaxies evolve over time.
Speaker 1: The discovery of M four seven to zero point eight
Speaker 1: is particularly significant because of its location within the Milky Way.
Speaker 1: It resides at the midpoint of a dust lane in
Speaker 1: the Galactic Bar, approximately twenty three thousand light years from Earth.
Speaker 1: The dust lanes of the galactic bar play a crucial
Speaker 1: role in transporting material from the outer disk of the
Speaker 1: galaxy toward its center as gas flows inward, simulates in
Speaker 1: dense ring like structures where star formation activity is intensified.
Speaker 1: The presence of a previously unknown GMC in this region
Speaker 1: suggests that the process of material accretion toward the galactic
Speaker 1: center is more complex than previously thought. Observations of M
Speaker 1: four seven to zero point eight have revealed important structural
Speaker 1: characteristics that provide insight into its composition and activity. The
Speaker 1: cloud stretches roughly one hundred and ninety five light years
Speaker 1: in galactic longitude and extends about sixty five light years
Speaker 1: in galactic latitude. It maintains a cold dust temperature of
Speaker 1: around twenty kelvin, highlighting its relatively undisturbed state. This low
Speaker 1: temperature aligns with the typical properties of GMCs, as these
Speaker 1: clouds must remain cold to allow gravity to overcome thermal pressure,
Speaker 1: facilitating the collapse of gas into dense star forming regions.
Speaker 1: One of the most striking aspects of M four seven
Speaker 1: to zero point eight is its internal structure, which exhibits
Speaker 1: two primary components. The first, dubbed the nexus, corresponds to
Speaker 1: the region with the brightest carbon monoxide emissions. This suggests
Speaker 1: it may be the densest and most active part of
Speaker 1: the cloud where gas and dust are accumulating in large quantities.
Speaker 1: The second feature, melon as the filament, is an elongated,
Speaker 1: narrow structure extending from the nexus. Bisfilamentary shape is a
Speaker 1: common trait among star forming regions, as elongated gas streams
Speaker 1: can funnel material towards sites of future star birth. Further
Speaker 1: investigation of M four seven to zero point eight uncovered
Speaker 1: evidence of ongoing or potential star formation. Two specific regions,
Speaker 1: may not be not E were identified as possible sites
Speaker 1: of early stellar development. Not E in particular, exhibits a
Speaker 1: cometary like shape and dense structure, leading astronomers to hypothesize
Speaker 1: that it could be a free floating, evaporating gas globule.
Speaker 1: These types of structures form when intense radiation from nearby
Speaker 1: young stars erode surrounding gas, sculpting the cloud into intricate forms. However,
Speaker 1: additional observations are necessary to confirm this possibility and to
Speaker 1: determine whether these knots will eventually give rise to new stars.
Speaker 1: The observations also revealed an intriguing shell like structure within
Speaker 1: M four seven to zero point eight. This feature appears
Speaker 1: to have a brighter rim in ammonia emissions, with a
Speaker 1: central cavity, suggesting an area where gas has been displaced.
Speaker 1: Such shell like formations can arise from various astrophysical processes,
Speaker 1: including the expansion of shock waves from stellar winds or
Speaker 1: supernova explosions. If this structure is indeed a remnant of
Speaker 1: past energetic activity, it could provide clues about the history
Speaker 1: of the cloud and its role in the dynamic environment
Speaker 1: of the Milky Way's central regions. The detection of M
Speaker 1: four seven to zero point eight not only enriches the
Speaker 1: current catalog of known GMCs, but also enhances the broader
Speaker 1: understanding of how molecular clouds evolve and contribute to galactic structure.
Speaker 1: By analyzing the properties of this cloud, astronomers can refine
Speaker 1: existing models of interstellar matter flow and star formation within
Speaker 1: bart spiral galaxies like the Milky Way. Future studies will
Speaker 1: focus on further characterizing the physical and chemical condition within
Speaker 1: M four section seven to zero point eight, as well
Speaker 1: as searching for additional signs of active star forming regions.
Speaker 1: The discovery underscores the importance of advanced radio telescopes like
Speaker 1: the GBT in probing the unseen structures of our galaxy.
Speaker 1: These powerful instruments enable astronomers to detect and analyze cold
Speaker 1: molecular gas that would otherwise be invisible at optical wavelengths.
Speaker 1: As observational techniques continue to improve, new insights into the
Speaker 1: interstellar medium and the mechanisms that drive star formation will emerge,
Speaker 1: deepening our knowledge of the cosmic processes that shape galaxies
Speaker 1: across the universe. Small protoplanetary disks challenge previous theories. Many
Speaker 1: of the protoplanetary disks where new planets form are significantly
Speaker 1: smaller than previously believed. Using the Atacama Large millimeter slash
Speaker 1: submillimeter Array ALMA, scientists from the Liden Observatory in the
Speaker 1: Netherlands examine seventy three protoplanetary discs located in the Lupus
Speaker 1: star forming region. Their observations revealed that a substantial number
Speaker 1: of young stars are surrounded by relatively modest disks of
Speaker 1: gas and dust, with some measuring as little as one
Speaker 1: point two astronomical units in size. This research, which has
Speaker 1: been accepted for publication in Astronomy and Astrophysics, provides an
Speaker 1: important connection between observed protoplanetary discs and the characteristics of exoplanets.
Speaker 1: Over the past decade, astronomers have used powerful radio telescopes
Speaker 1: like ALMA to capture images of hundreds of protoplanetary discs
Speaker 1: surrounding young stars. Many of these discs extend well beyond
Speaker 1: the uns The orbit of Neptune when compared to the
Speaker 1: size of our Solar system. Additionally, many of them display
Speaker 1: gaps where giant planets are thought to be forming. However,
Speaker 1: new research conducted by pH dot d Candidate Osmar M.
Speaker 1: Geral Varado, postdoctoral researcher Marianna B. Sanchez an assistant professor
Speaker 1: Nancer Vander Merrill from the Leiden Observatory suggests that these
Speaker 1: large discs may not actually be representative of the typical
Speaker 1: protoplanetary disc. By utilizing Alma, the researchers conducted observations of
Speaker 1: all the known protoplanetary discs surrounding young stars in the
Speaker 1: Lupus Region, a star forming area situated approximately four hundred
Speaker 1: light years from Earth in the southern constellation of Lupus.
Speaker 1: Their findings indicate that two thirds of the seventy three
Speaker 1: discs studied are relatively small, with an average radius of
Speaker 1: just six astronomical units, roughly equivalent to the orbit of Jupiter.
Speaker 1: The smallest disk identified in the study measured only zero
Speaker 1: point six astronomical units in radius, making it even smaller
Speaker 1: than Earth's orbit around the Sun. These discoveries fundamentally change
Speaker 1: the existing understanding of what constitutes a typical protoplanetary disc.
Speaker 1: The brightest discs, which are the easiest to observe, tend
Speaker 1: to exhibit large scale gaps, while compact discs without such
Speaker 1: substructures are far more common. Most of the small discs
Speaker 1: were found around low mass stars with masses ranging between
Speaker 1: ten percent and fifty percent of the Sun's mass. This
Speaker 1: type of star is the most common in the universe.
Speaker 1: The observations also suggest that these compact discs may provide
Speaker 1: ideal conditions for the formation of super earths, since most
Speaker 1: of the dust in these systems is located close to
Speaker 1: the star, precisely where super earths are frequently found. Super
Speaker 1: Earths are rocky planets similar to Earth, but with masses
Speaker 1: that can reach up to ten times that of our planet.
Speaker 1: This could help explain why super earths are more commonly
Speaker 1: detected around low mass stars. The findings also suggest that
Speaker 1: the Solar System originated from a large protoplanetary disc that
Speaker 1: gave rise to massive gas planets like Jupiter and Saturn,
Speaker 1: but did not produce any super earths. Given that super
Speaker 1: earths are thought to be the most prevalent type of
Speaker 1: planet in the universe, this makes the solar system somewhat
Speaker 1: unusual compared to the broader population of planetary systems. The
Speaker 1: study provides a crucial missing link between the observed characteristics
Speaker 1: of protoplanetary disks and the properties of known exoplanets. The
Speaker 1: fact that the majority of small discs do not exhibit
Speaker 1: large gaps suggests that most stars do not host giant planets.
Speaker 1: This aligns with exoplanet observations of mature stars, reinforcing the
Speaker 1: connection between disc populations and planetary systems. Prior high resolution
Speaker 1: ALMA studies primarily focused on bright discs, which are often
Speaker 1: significantly larger. In contrast, smaller discs had generally been studied
Speaker 1: only in terms of their brightness, with their sizes remaining uncertain.
Speaker 1: Capturing high resolution images of these fainter discs posed a challenge,
Speaker 1: and it was previously unclear whether ALMA would be capable
Speaker 1: of resolving them. For this research, scientists utilized ALMA observations
Speaker 1: taken in twenty twenty three and twenty twenty four with
Speaker 1: the highest possible resolution of zero point zero three sis
Speaker 1: zero arcseconds. In addition, they incorporated archival data to compile
Speaker 1: the first ever complete high resolution survey of an entire
Speaker 1: star forming region. The results demonstrate that previous assumptions about
Speaker 1: the typical size and structure of protoplanetary discs were incorrect.
Speaker 1: Until now, studies have been heavily biased towards the brightest
Speaker 1: and largest discs. By expanding the scope to include discs
Speaker 1: of all sizes, a more comprehensive and accurate understanding of
Speaker 1: the early stages of planet formation has finally emerged. The
Speaker 1: FAM