Podcast Summary
Misconception about the Big Bang and Black Holes: The Big Bang is the origin of the universe, not a destructive event. Black holes, which form from massive stars, merge during galaxy collisions and do not get destroyed as suggested in the question.
The Big Bang is the origin of the universe, not the destruction of supermassive black holes. Black holes, which are the remnants of massive stars, exist at the centers of most galaxies. When galaxies collide, their black holes merge, forming a new supermassive black hole. Black holes do evaporate over extremely long timescales due to quantum effects, but they are not destroyed in the way that the question suggests. This misconception likely arises from the poetic language often used to describe black holes and their destructive potential. The StarTalk team encourages listeners to ask their cosmic questions and engage in scientific discussions.
The Universe's Age: From 10 Billion to 13.75 Billion Years: The scientific process, driven by the Hubble constant, refined the universe's age from early estimates to the currently accepted value of approximately 13.75 billion years. Black holes, despite their immense mass, are not affected by the existence or creation of other universes.
The universe's age has been refined significantly over time, from estimates as low as 10 billion years to the currently accepted age of approximately 13.75 billion years. This progress was driven by the Hubble constant, a measurement of the universe's expansion rate, which was the subject of much debate and research. The discovery of this constant by Edwin Hubble in the 1920s helped establish the modern understanding of the universe's age. Despite early uncertainties, the scientific process, which values facts over personal biases, ultimately led to a more accurate determination of the universe's age. Additionally, black holes, despite their immense gravity and mass, are not affected by the existence or creation of other universes, as there is currently no known force capable of destroying them.
Discovering the origins of heavy elements and planets' weights: Through scientific inquiry, our understanding of the universe and its elements has evolved, leading to discoveries like heavy elements originating from supernovae and the difference between a planet's weight and mass.
Our understanding of the universe and its elements has evolved over time. For instance, the discovery that heavy elements like gold on Earth originated from supernovae was not known when Neil deGrasse Tyson was a kid in chemistry class. Instead, the answer was that elements found in the ground were where they came from. However, with the advancement of astrophysics, we now know that these elements are formed in the crucibles of high-mass stars and scattered into the galaxy upon their explosion. This discovery was a significant one, earning a Nobel Prize. Another question touched on the measurement of a planet's weight, which is not the same as mass. The Earth, for example, is in free fall towards the sun and is weightless in that sense. Therefore, when measuring a planet's weight, we actually mean its mass. These examples illustrate the importance of ongoing scientific inquiry and the evolution of our knowledge.
Understanding Weightlessness and Mass in Space: Objects in space are weightless due to being in free fall, but they still have significant mass, such as Earth's 6 sextillion tons.
Everything in the universe, including the Earth, is weightless in the sense of having no net force acting upon it when in free fall or orbit around a larger mass. However, this doesn't mean Earth or any other object has no mass. The Earth's mass was first measured by Henry Cavendish, a British scientist, and it's a hefty number, coming in at 6 sextillion tons. Despite its mass, Earth isn't in danger from asteroid impacts because the relative size difference makes the impact minimal. So, the weightlessness of objects in space and their actual mass are related concepts. The weight loss analogy is a useful way to understand this - when you're on a weight loss program, you're trying to reduce the mass (or number of atoms) in your body. Similarly, in space, objects are weightless because they're in free fall, but they still have mass.
Principle of Conservation of Angular Momentum: The total angular momentum in a closed system remains constant, causing systems under gravity to spin faster as they collapse.
Everything in the universe, including planets, solar systems, and galaxies, spins due to the conservation of angular momentum. This principle states that the total amount of angular momentum in a closed system remains constant. When a system collapses under the influence of gravity, any initial motion increases, causing the system to spin faster. This explains why kids can make spaghetti flap in their faces as they suck on it, and why everything in the universe, from galaxies to subatomic particles, exhibits some form of spin. This major principle in physics is essential for understanding various phenomena in the cosmos.
Discovery of Multi-Star Systems with Stable Planets: Contrary to initial beliefs, multi-star systems with stable planets exist, challenging our understanding of celestial mechanics and expanding the potential for habitable worlds
The universe is home to a vast array of multi-star systems, including some with as many as four suns. Contrary to initial assumptions, these systems are not unstable, and planets can potentially orbit around them stably. The existence of these systems was first discovered when astronomers realized that many stars in the night sky appeared closer than they should be based on random distribution. Through statistical analysis, it was determined that these close groupings were indeed real, leading to the discovery of double, triple, and even quadruple star systems. While planets cannot orbit directly among these stars due to instability, they can potentially orbit within the stable regions of these systems, much like planets in our solar system orbit the sun. This discovery challenges our understanding of celestial mechanics and opens up new possibilities for the existence of habitable planets in multi-star systems.
Light's Mass and Gravity: Light, which carries energy, has a mass equivalent, causing it to be affected by gravity. Even light is subject to the laws of gravity and can be bent by massive objects like black holes.
Mass and energy are interconnected, and light, which has energy, has a mass equivalent to that energy. Therefore, a mass, such as a black hole, has a gravitational field that can pull light into it. This was demonstrated during a total solar eclipse when the bending of starlight as it passed by the Sun was measured, confirming Einstein's theory of relativity. Gravity doesn't actually curve light, but rather curves the fabric of space-time, and light follows this curvature. This means that even light is subject to the laws of gravity and can be affected by massive objects like black holes. Additionally, there are possibilities of life existing on planets that are not orbiting stars, called planetary vagabonds, which could have internal heat sources and harbor life.
Gravity warps space, causing light to follow curved paths: Gravity warps space, making it essential for understanding phenomena like black holes, and drives scientists to explore the unknown despite potential dangers.
Both gravity and space play crucial roles in shaping the paths of objects, including light. Gravity doesn't curve the path of light; instead, it warps space, causing light to follow a curved path. This concept can be compared to NASCAR racing, where a banked track allows drivers to maintain a straight course while making turns. In the universe, this concept is essential for understanding phenomena like black holes, which distort space around them, making it impossible for objects, including probes, to escape their grasp. Yet, despite the dangers, the quest for knowledge drives scientists to explore the unknown, including the possibility of sending probes into black holes when the opportunity arises.
Understanding Black Holes and Dark Matter: Black holes are cosmic entities that impact nearby stars and emit intense energy, while dark matter is a mysterious substance scattered throughout the galaxy that interacts little with regular matter and is not found in solid structures or inside individuals.
Black holes are powerful cosmic entities that can significantly impact nearby stars and emit intense energy. They are detected through the material descending into them and the radiation produced. If we were to encounter one, we could potentially gain valuable knowledge about its gravitational and radiation fields. However, we currently have no plans to probe a black hole due to our limited understanding of our own solar system and the potential dangers involved. As for dark matter, it is a mysterious substance that interacts very little with regular matter and is scattered throughout the galaxy in large quantities. It does not form solid planets or other localized structures, making it difficult to find meaningful amounts of it in any one place. Contrary to popular belief, it is not in your bedroom or inside of you, and the universe's expansion does not directly affect individual beings.
The universe expands, but we don't: Molecular forces keep us together in the expanding universe, but our solar system and galaxy change as we age, with dark energy present in cosmic vacuums. Keep learning and appreciating the wonders of the universe.
Despite the universe's expansion, we and our galaxy do not expand with it. The molecular forces that keep us together are stronger than the force of the universe's expansion. However, as we hit middle age, our solar system and galaxy begin to experience changes. This discussion also touched upon the presence of dark energy in vacuums throughout the cosmos. Leanne Lord, a guest on StarTalk Radio, shared these insights with host Neil deGrasse Tyson, emphasizing the importance of continuing to learn and appreciate the wonders of the universe. As Leanne follows Neil on Twitter, she encourages listeners to do the same for an ongoing source of knowledge and laughter. Remember, we are just a small part of the vast cosmos, but understanding it can bring us great joy. Keep looking up!