Podcast Summary
Understanding Stars through Starquakes: Astroseismology reveals a star's internal structure and evolution through analysis of starquakes, which are harmless sound waves in stars
Stars, unlike Earth, do not have solid crusts for earthquakes to occur in the traditional sense. Instead, stars are gaseous fluids that experience constant up and down motions, leading to the creation of sound waves or "starquakes." Asteroseismology, the study of starquakes, allows scientists to learn about a star's internal structure and evolution by analyzing these waves. Unlike earthquakes on Earth, which can cause devastation, starquakes do not pose a threat to us since they dissipate quickly. Stars can be thought of as three-dimensional musical halls, constantly vibrating and producing sound waves that reveal valuable information about their interiors.
Discovering Stars' Internal Sounds and Structures: Stars produce internal sounds detected through brightness changes, seismographs help model interiors, frequencies reveal physics and composition, and each star has a unique 'symphony'.
Stars produce internal sound waves due to their up and down motions, and these waves can be detected through changes in the star's brightness. Seismographs help us measure these changes and model the star's interior structure. The frequencies of these sound waves are connected to the physics and chemical composition of the star. We cannot hear these sounds directly, but we can measure their frequencies and even convert them into music through a process called sonification. Each star has its unique symphony based on its size, mass, and age. This field allows blind people to become astronomers by shifting the global symphony into the audible range. The largest recorded quake not found on Earth refers to seismic activity within stars, and all planets may not have tectonic plates that shift like Earth's.
Planets have quakes too, but they're different: All planets, including gaseous ones, experience quakes. Their frequency and characteristics depend on their density and composition. Observing changes in brightness or gas variations can reveal seismic activity, even in ice giants. Studying these quakes helps us understand a planet's size, density, and mass.
All planets, including gaseous ones like Jupiter and Saturn, experience quakes, just like Earth. The frequency and characteristics of these quakes depend on the density and composition of each planet. For example, ice giants like Uranus and Neptune may have different quake experiences due to their icy compositions. While we cannot directly measure these quakes like we do on Earth, we can observe changes in brightness or gas variations to infer seismic activity. The largest recorded quakes can take months to occur in massive stars, unlike the seconds-long quakes we're familiar with on Earth. By studying these quakes, scientists can learn valuable information about a planet's size, density, and mass.
Learning from stellar oscillations in stars: Stellar oscillations, or starquakes, provide insights into a star's age, structure, and core properties. All types of stars exhibit these phenomena, not just dying or supermassive ones.
Starquakes, or stellar oscillations, are not the sudden and short-lived events we associate with earthquakes on Earth. Instead, they are long-lasting phenomena that can occur in various types of stars, not just dying or supermassive ones. These oscillations can provide valuable information about a star's age, structure, and core properties. Connie Aerts, an expert in asteroseismology, explained that we refer to these events as stellar oscillations in professional contexts. Unlike earthquakes, which can be destructive and require shelter, stellar oscillations would not pose a threat to us if they occurred on Earth. Instead, we would experience continuous, long-term changes in the planet's climate and tides. Dylan and Alejandro, two listeners, asked about what we can learn from these oscillations, specifically if we can determine a star's age and understand its core. Connie confirmed that, indeed, we can glean important insights from these events. She also mentioned that all types of stars, not just dying or supermassive ones, exhibit oscillations. Overall, the discussion highlighted the fascinating and complex nature of stellar physics and the ongoing discoveries that come from studying these phenomena.
New insights into star internal rotation from starquakes: Starquakes reveal stars rotate faster internally, challenging theories and extending star lifetimes
The analysis of starquakes has provided new insights into the internal rotation of stars, which was previously unknown. This discovery has challenged existing theories about how stars evolve and revealed that these theories need to be revised. The rotation of stars affects how their material is mixed, and this can significantly impact their life expectancy, particularly for massive stars. The measurement of internal rotation frequencies in over 2,000 stars has shown that their lives may be longer than previously estimated. The discovery of these frequency shifts in starquakes has opened up a new avenue of research in astrophysics.
Faster rotation leads to longer star lifespan: Stars with faster rotation bring more fuel into their cores, increasing their lifespan. The stirring effect of rotation does not speed up fusion but brings more fuel, and once fusion starts, stars can sustain it for a long time.
The rotation of a star plays a significant role in its lifespan. The faster a star rotates, the more hydrogen it brings into its nuclear reactor core, resulting in a longer life. This is because the increased rotation brings more fuel into the high-density and high-temperature areas where nuclear fusion occurs. Contrary to what one might expect, the stirring effect of rotation does not speed up the fusion reaction but instead brings more fuel into the core. Once nuclear burning is ongoing, the nuclear fusion in stars is stable, and these stars can sustain this process much better than we can. However, even a small change in the amount of fuel in the core, such as increasing it by 2%, can lead to a significant increase in the star's lifetime. Additionally, stars can experience "starquakes," which can be caused by various reasons, including tidal forces from binary star systems. These oscillations can be strong enough to cause noticeable changes in the star's shape.
Betelgeuse's dimming: A natural process for red giants: Betelgeuse's dimming is a natural process for red giants near the end of their life, providing astronomers with valuable data for studying the eventual supernova explosion and the creation of new elements in the universe.
Betelgeuse, a large and bright red giant star, experienced a significant dimming about a year ago, causing concern among stargazers. However, this is a normal behavior for such stars as they near the end of their life and expel material, making it difficult for astronomers to study their oscillations. The dimming does not indicate an imminent supernova explosion, but rather a natural process that can take some time. Astronomers view this as an exciting opportunity to gather more data about the star's behavior and the eventual supernova explosion, which will enrich the galaxy with essential elements. Despite the misconception that a star explosion is always a negative event, it is a necessary process for the creation of new elements and the continuous evolution of the universe.
Asteroseismology: Starquakes and Space Telescopes: Asteroseismology uses long-term data from space telescopes to study starquakes and their effects. Advanced telescopes offer groundbreaking discoveries but may not be ideal for asteroseismology due to data length requirements.
Asteroseismology, the study of starquakes and their effects on stars, relies heavily on long-term, continuous observations made by space telescopes like Kepler, TESS, and future missions like PLATO. These telescopes provide the necessary data for asteroseismologists to distinguish different frequencies of quakes and understand their significance. The James Webb Space Telescope, while an incredible instrument for observing the early universe in infrared, is not the best tool for asteroseismology due to its short-term observations and the priority given to extragalactic science. The field requires a trade-off between using the most advanced telescopes for groundbreaking discoveries and utilizing more accessible or less cutting-edge telescopes for specific tasks. The computational challenge lies in the need for extended data baselines to separate and analyze the various frequencies of quakes.
The Importance of Long-Term Observations in Astronomy: Long-term observations are crucial for understanding the oscillations and behaviors of stars and their planets, requiring dedicated missions like Kepler and PLATO.
The precision of measuring astronomical frequencies depends on the length of the observation time. For instance, if we measure something for 4 years, we cannot make meaningful conclusions about frequencies that occur on 2-year time scales because we would only have seen a fraction of a cycle. To accurately identify and study these frequencies, we need long-term data, which requires dedicated space missions like Kepler and future projects like PLATO. These missions are crucial for understanding the oscillations and behaviors of stars and their planets. Sunspots, solar flares, and coronal mass ejections (CMEs) are phenomena related to the sun's activity. While they can disturb the periodic oscillations of the sun, they do not pose a direct threat to Earth. The sun's gravity is not negatively affected by CMEs of significant size. The starquake that occurred in 2004, despite releasing a massive amount of energy, did not harm Earth due to its safe distance from our planet. In summary, the importance of long-term observations in astronomy cannot be overstated. The study of oscillations and behaviors of stars and their planets relies on accurate and extensive data, which can only be obtained through dedicated missions like Kepler and PLATO. Sunspots, solar flares, and CMEs are important aspects of the sun's activity, but they do not pose a direct threat to Earth.
Understanding Starquakes and Their Impact on Us: Starquakes are periodic phenomena that expand and contract stars while maintaining spherical symmetry, unlike disruptive coronal mass ejections. Our solar system is not binary due to statistical chances and the unique formation of our solar system.
Stars exhibit various types of oscillations, including starquakes, which are not dangerous to us despite causing disturbances to our electronics. Starquakes are a smooth, periodic phenomenon, unlike coronal mass ejections, which can be abrupt and disruptive. The largest energetic oscillations are radial oscillations, which expand and contract the star while maintaining spherical symmetry. Stars, in general, are variable, with some exhibiting more noticeable oscillations than others. As for why our solar system is not binary, half of stars with the mass of the sun are in binary systems, so it's a statistical even chance. The formation and evolution of our solar system may not have resulted in a binary companion.
The sun may have had a twin during its formation: Many stars, including those similar to the sun, have twins but only half survive and live as binary systems.
The sun may have had a twin during its formation, but only half of stars born with similar masses survive and live their lives together. This phenomenon, known as stellar multiplicity, is common among stars with masses 10 to 100 times greater than the sun. The fate of the sun's twin is unknown, but it could have led to intriguing sci-fi scenarios, such as a dramatic explosion or a long-lived binary system. During the StarTalk interview, astrophysicist Neil deGrasse Tyson discussed these concepts with Connie Walker, a visiting scholar in New York City. They also touched upon the significance of studying astrophysics and the importance of public engagement with scientific knowledge. Overall, the conversation highlighted the wonders of the universe and the importance of exploring the unknown.