Podcast Summary
Beyond planets: Understanding brown dwarfs: Brown dwarfs, larger than planets but smaller than stars, exist in the solar system and are an important area of study in astronomy.
Our sun is indeed the only star in our solar system, but there are objects, such as brown dwarfs, that are larger than planets but smaller than stars, which exist in the netherworld between planets and stars. Jackie Faraday, an expert in this field, clarified this misconception when a listener asked about the size of the sun compared to other stars in our solar system. Additionally, during the conversation, Jackie was asked about her beliefs regarding zodiac signs. She acknowledged that it was a twofold question, with one part being a genuine interest in the cosmos and the other being a personal interest in her. Furthermore, the discussion highlighted the importance of the American Museum of Natural History as an intellectual center for research in the field of astronomy and astrophysics. The museum's Brown Dwarfs New York City Research Group, led by Jackie, has even created a logo inspired by the New York City subway symbol. The episode showcased the expertise of Jackie Faraday and the collaborative nature of scientific research, with Neil deGrasse Tyson acting as a facilitator and providing insightful comments. Overall, the conversation emphasized the ongoing exploration and discovery in the field of astronomy and the importance of asking questions to deepen our understanding of the universe.
The Outer Solar System's Massive and Eccentric Bodies: The Kuiper Belt hosts many celestial leftovers, while theories propose a massive outer body, Nemesis, and massive stars like Eta Carina challenge our understanding of stellar systems.
Our solar system is not alone in harboring massive and eccentric celestial bodies. The Kuiper Belt, located at the outer edge of the solar system, is home to many leftover objects from the solar system's formation. While there are theories suggesting the existence of an object with an eccentric orbit beyond the Kuiper Belt, known as Nemesis, no definitive evidence has been found. However, the existence of massive stars, like Eta Carina, which is a binary star system with a combined mass of up to 100 times that of our sun, is well-established. These stars, which can have eccentric and unstable orbits, challenge our understanding of stellar systems and add to the richness and complexity of the universe.
Exploring Carina and Eta Carinae, Differences between Luminous Blue Variables and Wolf-Rayet Stars, and Zodiac Signs: Carina's Eta Carinae, once a bright star, underwent explosions, forming a nebula. Luminous blue variables and Wolf-Rayet stars differ in characteristics. Zodiac signs have astronomical significance in eclipses' paths, but astrological interpretations lack scientific basis. Exoplanet study requires advanced tools to uncover their nature and composition.
The night sky is full of fascinating celestial bodies, from constellations and their mythological tales to stars with unique properties and even potential black hole candidates. During the discussion, we explored the constellation Carina and its brightest star, Eta Carinae. This star, once one of the brightest in the night sky, underwent massive explosions, creating a stunning nebula. We also learned about the differences between luminous blue variables and Wolf-Rayet stars, two categories of stars that have distinct characteristics. Additionally, we touched upon the topic of zodiac signs, acknowledging the astronomical significance of the eclipses' paths, but expressing a lack of belief in astrological interpretations. Regarding the understanding of exoplanets, the need for advanced tools and resources is crucial to unravel their nature and composition.
Classifying Celestial Bodies: Planets vs. Brown Dwarfs: Brown dwarfs, despite similarities to planets, are classified differently due to their location and mass. They're 'failed stars' that cool instead of fusing fuel, and the boundary between them and stars is around 75 Jupiters in mass but depends on metallicity.
The classification of celestial bodies, specifically between planets and stars, can be subjective and depends on their location. The expert in the discussion focuses on studying "orphan" objects, those without a host star, which are referred to as brown dwarfs when they have similar mass and temperature as planets orbiting stars. The controversy lies in the fact that these objects, despite their similarities, are classified differently based on their location. Brown dwarfs are formed from the same molecular clouds as stars but fail to reach the mass required for nuclear fusion. They exist as "failed stars," cooling through their lives instead of maintaining a nuclear engine. The boundary between a brown dwarf and a star is around 75 Jupiters in mass, but this is dependent on metallicity. This discussion highlights the complexities and nuances in the classification of celestial bodies and the role location plays in their identification.
The formation of stars and their accompanying disks can lead to rogue planets or rogue worlds: New stars form from molecular clouds and come with disks of material. Some fragments may become rogue planets or rogue worlds, which can be ejected from their solar systems or join another star.
The universe between stars and planets is filled with dynamic and complex phenomena. Jackie Faherty, an astrophysicist at the American Museum of Natural History, explained that molecular clouds can break apart to form stars, and each new star comes with a disk of material that can also fragment into smaller objects. These formation mechanisms provide crucial information about the nature of these celestial bodies. Some of these objects may become rogue planets or rogue worlds, which can be ejected from their solar systems or join another star. The discovery of interstellar objects like Oumuamua, an asteroid that passed through our solar system, highlights the possibility of these wandering celestial bodies. Despite the vast emptiness of space, these discoveries show that there is a rich and intriguing world between stars and planets.
Stellar flybys impact on planetary systems: Stellar flybys can significantly alter planetary systems, as shown by Oumuamua's possible encounter with another star before entering our solar system. The next stellar flyby, in a million years, may impact our Oort cloud but is not expected to be catastrophic.
Stellar flybys, the interactions between stars as they pass by each other, can have significant impacts on planetary systems. The discussion revolved around Oumuamua, an interstellar object that passed through our solar system in 2017. Its hyperbolic velocity indicated it came from outside our solar system, and its trajectory suggested it might have had a close encounter with another star before encountering ours. This encounter could have altered Oumuamua's course slightly. The researchers are investigating if we were its first encounter after it departed from its home star system. Stellar flybys can change the structure of planetary systems, including our own, which is an exciting new area of study in astronomy. In about a million years, our solar system will experience a stellar flyby by a star smaller than the Sun, which will pass within our Oort cloud. The impact on the Oort cloud, the outer region of our solar system containing trillions of comets, is uncertain but not expected to be catastrophic.
Exploring the Oort Cloud and the Approaching Star: The Oort cloud's role in our solar system's dynamics and the potential encounter with a nearby star offer exciting possibilities for scientific discovery and exploration.
The Oort cloud, an icy body at the outermost edge of our solar system, stretches a third of the way to the nearest star. This means that the Oort cloud, which holds icy bodies that occasionally come close to the sun, plays a significant role in our solar system's dynamics. The stars we observe in our night sky, such as Gleeson 780780, are selected for their fast movement in our field of view, making them appear closer. The upcoming encounter with this star, which is heading towards our solar system, could potentially lead to exciting discoveries, such as new Oort cloud intersections and possible exploration missions. Moreover, the discussion touched upon the idea that Jupiter, the largest planet in our solar system, might have once been a failed star. While this theory is still a topic of debate among scientists, it highlights the intriguing nature of celestial bodies and their complex origins. As we continue to explore the vastness of space, it's essential to remember that our understanding of the universe is constantly evolving. Our fascination with the stars, planets, and other celestial bodies not only drives scientific discovery but also fuels our collective imagination.
Jupiter: Overachieving Planet and Solar System Protector: Jupiter, the largest planet, is not a failed star but an overachieving planet, generating more energy than it receives, protecting Earth from asteroids, and maintaining its planetary status.
Jupiter, despite being the largest planet in our solar system and not having ignited its core to become a star, should not be considered a failed star but rather an overachieving planet. Jupiter protects Earth by shielding us from asteroids and comets, acting as the "bouncer" of the solar system. Although Jupiter has more than three times the mass needed to enter the brown dwarf regime, it is still emitting more energy than it receives from the sun. This means Jupiter is a net energy generator in the solar system. If Jupiter had ten times its current mass, it would begin to enter the brown dwarf regime and become a star. However, Jupiter's current mass keeps it in the planet category, and its protective role makes it an essential part of our solar system.
The beautiful HR 8799 planetary system and its multiple directly imaged planets: The HR 8799 system, known for its aesthetic appeal and scientific significance, has multiple planets discovered using advanced imaging techniques. Theoretically, massive planets could transform into stars, but it's highly unlikely for Earth-like planets.
The HR 8799 planetary system, also known as the "Brad Pitt of planetary systems," is particularly beautiful and worth studying due to its multiple directly imaged planets. This system, located in the constellation Pegasus, is popular among astronomers for its visual appeal and scientific significance. The system's planets were discovered using specialized cameras such as coronagraphs and adaptive optics systems. It is possible for multiple formation mechanisms, such as gravitational fragmentation and accretion, to occur simultaneously and result in the formation of various objects, including stars and planets, within a single system. During a lightning round segment, a 7th grade science teacher asked questions on behalf of her students about the number of stars in the universe and the possibility of turning a planet into a star. The answers provided were that the number of stars in the universe is estimated to be beyond comprehension, and that while it is theoretically possible for a massive planet to undergo a process called "core collapse" and transform into a star, it is highly unlikely for a terrestrial planet like Earth to do so.
Estimating the number of stars in the observable universe: Astronomers estimate there could be 100 sextillion to 200 sextillion stars in the observable universe, a number too large for the human mind to fully grasp.
The universe is vast beyond comprehension. During the discussion, it was estimated that there could be anywhere from 100 sextillion to 200 sextillion stars in the observable universe. This is a number so large that it's hard for the human mind to grasp. To put it into perspective, a sextillion is a number with 21 zeros. Astronomers use various techniques to study different celestial bodies, such as directly imaging the atmospheres of brown dwarfs using infrared instruments. The study of the universe and its mysteries is a fascinating field, and astronomers play a crucial role in unlocking its secrets.
Understanding Brown Dwarfs: Beyond Solid Surfaces: Brown dwarfs, though larger than planets, lack solid surfaces and are studied through their atmospheres. They serve as key objects for understanding planetary atmospheres, particularly hot Jupiters, but their solid cores remain a mystery.
Brown dwarfs, despite being larger than planets, do not have solid surfaces that we can stand on like Jupiter or Saturn. Instead, they are considered "souped up" gas giants, and their study relies on the detection of their atmospheres through methods like the transit method, where the light passing through the host star is analyzed for any changes. Brown dwarfs serve as the ground truth for studying the atmospheres of transiting planets, particularly hot Jupiters. However, the existence of a solid core within a brown dwarf is still unknown. Overall, the study of brown dwarfs is complex and ongoing, with many questions still unanswered.