Podcasts > StarTalk Radio > Stars Talk to Neil – Reversing Earth’s Rotation

Stars Talk to Neil – Reversing Earth’s Rotation

By StarTalk Radio

Dive into an exploration of life, death, and the wonders of physics with the dynamic team of Chuck Nice, Gary O'Reilly, and Neil deGrasse Tyson, complemented by guest insights from Sway Calloway, J.B. Smoove, and Rob Reiner on the StarTalk Radio podcast. This episode invites listeners to ponder the scientific principles that govern everything from our final fate to the flights we take across the skies.

Neil deGrasse Tyson captivates with explanations ranging from the afterlife of atoms and the generation of lift by aircraft wings, to the possibility of rainbows existing beyond Earth. Whether discussing the transformation of human remains into energy that traverses the cosmos or breaking down the aerodynamics that allow airplanes to soar – each topic is presented with the flair and educational prowess that StarTalk listeners have come to appreciate. Meanwhile, the musings on extraterrestrial rainbows offer a perspective that marries science with poetic imagination, showcasing the endless allure of the cosmos.

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Stars Talk to Neil – Reversing Earth’s Rotation

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Stars Talk to Neil – Reversing Earth’s Rotation

1-Page Summary

What happens after we die, according to science

Neil deGrasse Tyson elucidates the scientific perspective on what transpires to our physical remains post-mortem. The transformation of our atoms and molecules is a key concept, with no true exit from the universe but a perpetual state of change. For those who choose cremation, the body's molecular energy is liberated into the atmosphere as heat and ultimately radiates as infrared photons into space at light speed. Alternatively, burial acts as sustenance for flora and fauna, completing the life cycle, as Tyson personally prefers. Biodegradable caskets with embedded seeds can further nurture the Earth through transformation into compost. Cremation results in the release of energy into the atmosphere, where it continues the cosmic energy cycle, despite the ashes retaining no energy after the process.

Physics of wings generating lift for flight

Neil deGrasse Tyson breaks down the physics behind lift generation by wings, guided by aerodynamics principles. The wings, structured with an upward angle, leverage the Bernoulli effect to create lift—the airflow over the wing travels faster compared to air beneath, generating lower pressure above the wing which translates to lift. Tyson employs a paper-and-breath experiment to demonstrate this. He also discusses the role of wing flaps, which extend during takeoff and landing to enhance lift in lower speeds. Additionally, the nose of an airplane tilts upward for takeoff, affirming that the wing's angle of attack is crucial for generating the necessary lift, exemplified by jets such as the Concorde.

Rainbows across the universe

Tyson spins a narrative about the beauty of rainbows, explaining their creation through the refraction and dispersion of sunlight in raindrops, revealing separate colors as light exits. He extends the concept, proposing that rainbows could form anywhere in the universe given Earth-like conditions, potentially in atmospheres with transparent liquids such as methane or ammonia. He also shares that from an aerial perspective, rainbows appear as full circles rather than the arches perceived from the ground, due to the viewer’s position relative to the raindrops.

1-Page Summary

Additional Materials

Clarifications

  • Atoms and molecules undergo transformation after death, whether through cremation or burial. During cremation, the body's molecular energy is released into the atmosphere as heat and infrared photons. Burial, on the other hand, allows the body to become sustenance for plants and animals, completing the cycle of life. This transformation process highlights the perpetual state of change in the universe post-mortem.
  • The Bernoulli effect in wing lift generation is a principle in aerodynamics where faster-moving air creates lower pressure. When air flows over an airplane wing, it moves faster over the curved upper surface, resulting in lower pressure compared to the slower-moving air beneath the wing. This pressure difference generates lift, allowing the aircraft to overcome gravity and achieve flight. The Bernoulli effect is a fundamental concept in understanding how wings generate lift during flight.
  • Wing flaps are movable surfaces on the trailing edge of aircraft wings that can be extended or retracted. When extended during takeoff and landing, wing flaps increase the wing's surface area, altering the airflow over the wing to generate more lift at lower speeds. This enhanced lift capability helps aircraft achieve safe takeoffs and landings by reducing the required speed for these critical flight phases. The adjustment of wing flaps is a crucial aerodynamic feature that improves an aircraft's performance during various stages of flight.
  • When sunlight enters a raindrop, it undergoes refraction, bending as it moves from air to water and back to air. This bending causes the different colors of light to separate due to their varying wavelengths, a process known as dispersion. The separated colors then reflect internally within the raindrop before exiting, creating the beautiful phenomenon we see as a rainbow.
  • Rainbows can form in atmospheres with methane or ammonia due to the refraction and dispersion of light in these transparent liquids, similar to how rainbows are created in raindrops on Earth. The conditions required for rainbow formation include sunlight interacting with these substances in a way that separates light into its component colors, resulting in a colorful arc or circle in the sky. This phenomenon is not limited to Earth's atmosphere but could potentially occur in other planetary atmospheres with suitable conditions for light refraction and dispersion. The presence of transparent liquids like methane or ammonia in the atmosphere can lead to the creation of rainbows under the right circumstances.

Counterarguments

  • While cremation releases energy, it also releases carbon dioxide and other pollutants, which can be environmentally harmful.
  • The concept of a life cycle completed by burial is a poetic interpretation; scientifically, it's a series of biochemical processes without inherent purpose or design.
  • Biodegradable caskets may not always decompose as intended due to varying soil conditions and other environmental factors.
  • The Bernoulli effect is one aspect of lift, but modern aerodynamics acknowledges that lift is also significantly generated by the deflection of air downwards by the wing, which is Newton's third law of motion in action.
  • The angle of attack is important, but there are limits to its effectiveness; too great an angle can lead to stalling, where lift is lost.
  • Rainbows require specific conditions to form, and while they could theoretically form in atmospheres with other transparent liquids, the exact appearance and formation process might differ due to the different refractive indices and physical properties of those liquids.
  • The full-circle appearance of rainbows from an aerial perspective is contingent on the presence of a sufficiently wide distribution of raindrops and the absence of obstructions, which may not always be the case.

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Stars Talk to Neil – Reversing Earth’s Rotation

What happens after we die, according to science

Neil deGrasse Tyson provides a scientific perspective on what happens to our physical form after death, emphasizing that nothing truly exits the universe but merely transforms.

Our atoms and molecules returning to the cosmos

Tyson explains that our atoms and molecules, which are not lost, transform after we die. For example, if you choose cremation, your body's molecules, which contain energy, will release that energy as they burn. This energy heats the air, which then enters the atmosphere. Eventually, it radiates infrared photons into space at the speed of light.

Being buried to nourish flora and fauna

Preferring to be buried himself, Tyson explains how being buried allows flora and fauna to dine upon his body. This natural process completes the circle of life. Tyson also references biodegradable caskets that come with seeds embedded. These caskets are meant to decompose, allowing the body to be consumed and transformed into compost, further nurturing the earth.

...

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What happens after we die, according to science

Additional Materials

Clarifications

  • Infrared photons are a type of electromagnetic radiation with longer wavelengths than visible light. When energy is released during cremation, it heats the air, causing the molecules to emit infrared photons. These photons travel at the speed of light, spreading out into space as a form of energy transfer. This process is part of the natural cycle of energy exchange in the universe.
  • During the burning process of cremation, the energy stored in the body's molecules is released as heat. This energy is a result of the chemical bonds within the molecules breaking down, leading to the liberation of heat energy. As the body burns, this released energy heats the surrounding air and contributes to the cremation process.
  • The cycle of energy in the cosmos describes ...

Counterarguments

  • The transformation of atoms and molecules after death is a physical process, but this does not address any metaphysical, spiritual, or religious beliefs about the afterlife, which are important to many people.
  • While cremation does release energy, it also releases carbon dioxide and other gases, which can contribute to pollution and climate change, raising environmental concerns.
  • The idea of burial nourishing flora and fauna is idealized; in modern cemeteries, embalming fluids and burial vaults can inhibit decomposition and prevent the body from returning to the ecosystem as efficiently.
  • Biodegradable caskets are a more eco-friendly option, but they may not be widely available or affordable for everyone, limiting their impact on nurturing the earth.
  • The energy released during cremation is indeed part o ...

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Stars Talk to Neil – Reversing Earth’s Rotation

Physics of wings generating lift for flight

Understanding the physics of how wings generate lift is crucial for realizing the marvel of flight. Neil deGrasse Tyson explains this phenomenon using principles of aerodynamics and examples of various aircraft.

Angle of the wing splitting and accelerating airflow

The wings of an airplane, such as the horizontally parked planes, are constructed with an inherent upward angle. Tyson explains that the creation of lift is a result of the Bernoulli effect, a principle where the airflow splitting at the wing's edge causes air traveling over the curved top to move faster than the air underneath.

Bernoulli effect

More specifically, as the air divides, encountering a wing, the path it takes over the curved upper surface is longer than the path underneath. This difference requires the air on top to travel faster to meet the slower moving air below at the trailing edge of the wing. According to the Bernoulli effect, the faster-moving air above the wing generates lower pressure than beneath the wing. Tyson demonstrates this with a simple paper-and-breath experiment: by blowing across the top of a paper strip, the faster air induces the bottom part to lift, showing how less pressure on top results in an upward force—lift.

Wing extending flaps during takeoff and landing

During the critical phases of takeoff and landing, when the airplane speeds are lower, extra lift is needed. Tyson notes that the wings extend their flaps during these stages to increase surface area and therefore, lift. He encourages observers to watch this transformation on an aircraft as it prepares ...

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Physics of wings generating lift for flight

Additional Materials

Clarifications

  • The Bernoulli effect explains how faster-moving air above a wing creates lower pressure, resulting in lift. This principle is crucial in understanding how wings generate lift for flight. It involves the airflow splitting at the wing's edge, causing the air above the wing to move faster than the air underneath. This difference in air speed creates a pressure differential that lifts the aircraft.
  • When air moves faster over the curved top of a wing, it covers a greater distance in the same time compared to the air underneath. This faster movement results in lower pressure above the wing according to the Bernoulli principle. The increased speed of the air molecules above the wing creates a region of lower pressure, which contributes to the lift force acting on the wing.
  • The shape and angle of a wing are crucial for generating ...

Counterarguments

  • The explanation of lift primarily through the Bernoulli effect is an oversimplification; lift is also significantly influenced by Newton's third law, where the downward deflection of air by the wing results in an upward reaction force.
  • The angle of attack is a more critical factor in lift generation than the upward angle of the wing's construction; wings can be designed with various shapes and still generate lift as long as the angle of attack is appropriate.
  • The role of wing flaps is not only to increase surface area but also to change the camber of the wing, which increases the wing's curvature and thus its ability to produce lift at lower speeds.
  • The statement that the shape of the wing is less critical than its function as a wing may be misleading, as the shape significantly affects the efficiency, stability, and performance of the wing in different flight conditions.
  • The nose tilting up during takeoff is not solely for generating lift; it is also to increase the angle of attack of the wings to a point where lift exceeds weight, allowing for takeoff.
  • The text does not ...

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Stars Talk to Neil – Reversing Earth’s Rotation

Rainbows across the universe

Neil deGrasse Tyson engages our curiosity by explaining the celestial phenomena of rainbows and how they could manifest beyond our planet.

Refraction and dispersion of sunlight through rain and other transparent liquids

Tyson illustrates that a rainbow’s creation is the result of sunlight being refracted, or bent, when it enters a raindrop, and the subsequent separation of colors as light leaves the raindrop. This is because different colors of light travel at varying speeds in the medium, causing them to spread apart and form the spectrum we see. Under the right conditions, with a wall of raindrops and the sun behind the observer at a proper angle, a rainbow becomes visible.

Further extending this captivating natural event beyond our own skies, Tyson speculates about the universality of rainbows. He suggests that anywhere in the universe, assuming the conditions mimic those on Earth—such as having rain or another transparent liquid in the sky—a rainbow can manifest. This includes the potential for rainbows to occur in ...

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Rainbows across the universe

Additional Materials

Clarifications

  • When sunlight enters a raindrop, it bends or refracts due to the change in speed as it moves from air to water. This bending causes the light to separate into different colors, a process known as dispersion. The different colors of light travel at varying speeds within the raindrop, leading to the formation of a rainbow with its distinct spectrum of colors. T ...

Counterarguments

...

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