NOVA has teamed up with Cook’s Illustrated to cook up a recipe for stars and black holes – a culinary “course” on how the most mysterious objects in the universe are created.
SCIENTIFIC NOTES:
* The relationship between information and energy comes from Landauer’s Principle, which connects the erasure of information and energy. But, more generally changes in information (e.g. recording information) are related to changes in energy. I will talk more about this in a future episode about the physics of memory, and why you will forget everything you ever knew! https://en.wikipedia.org/wiki/Landauer%27s_principle
* The numbers calculated in this video give a lower limit on the energy to record a particular amount of information, but to create a more permanent storage of information would require more energy.
* Retina display resolution, as it’s name implies, is similar to the eye’s resolution.
What makes a brain or machine conscious? Will robots become more conscious than we are? One theory, which can actually calculate consciousness, is beginning to provide some answers.
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Scientific notes:
Stellar mass black holes vs. supermassive black holes
* Stellar mass black holes form from the collapse of massive stars at the ends of their lives, so they have roughly the same mass as a star. Supermassive black holes are physically identical to their smaller counterparts, except they are 10 thousand to a billion times the size of the sun. However, their formation is more of a mystery. They may form from the merging of smaller black holes. http://astronomy.swin.edu.au/cosmos/S/Supermassive+Black+Hole
Supermassive black holes at the center of galaxies
* Almost every large galaxy has a supermassive black hole at its center, but researchers are not yet sure (https://jila.colorado.edu/research/astrophysics/black-holes-galaxies) why that’s the case, how they originate, and what their role is in the creation and evolution of galaxies.
Why are stars different colors?
* The color of a star depends on its temperature (http://www.atnf.csiro.au/outreach/education/senior/astrophysics/photometry_colour.html). The hotter a star, the higher energy its light will be. Higher energy/temperature corresponds with the blue end of the visible spectrum and lower energy/temperature corresponds with the red end.
How does dark matter make stars spin faster?
* In the 1960s, astronomers Vera Rubin and Kent Ford noticed that stars at the edges of galaxies were moving just as fast as stars at the center, which surprised them: it appeared that the force of gravity causing stars to orbit the center of the galaxy was not weakening over distance. Their observation implied that something else, distributed throughout the galaxy, was exerting a gravitation pull. We now know that that “something else,” now named dark matter, accounts for about 85% of the matter in the universe. (It existence was inferred in the 1930s, when the astronomer Fritz Zwicky(http://www2.astro.psu.edu/users/rbc/a1/week_10.html) noticed that galaxies in clusters were moving faster than they should.)
Size of the universe
* The universe is only 13.8 billion years old, but has a radius of about 46 billion light-years. If nothing can travel faster than the speed of light, how can that be? The expansion of the universe, driven by dark energy, is causing distances between objects to grow. Note that it is not moving those objects apart; rather, it is increasing the amount of space between them. https://phys.org/news/2015-10-big-universe.html
Cosmic webs
* Galaxies are not distributed randomly (http://skyserver.sdss.org/dr1/en/astro/structures/structures.asp) in space; instead, clusters of galaxies form web-like patterns. These webs consist of filaments, where dark matter and ordinary (baryonic) matter are concentrated, and voids, where galaxies are scarce. Researchers believe that these large-scale structures grew out of minor fluctuations in density at the beginning of the universe.
Composition of the early universe
* Moments after the Big Bang, the universe formed the nuclei for what would be come the universe’s hydrogen and helium atoms, with one helium nucleus for every 10 or 11 hydrogen (http://umich.edu/~gs265/bigbang.htm). When the first stars formed, there were no heavier elements — those elements formed inside stars.
String Theory Landscape
* The String Theory Landscape is a theory that the universe we live in is one of many universes. It attempts to explain how certain constants of nature seem “fine-tuned” for life, which contradicts the anthropic principle, or the notion that we humans hold a special place in the universe. https://www.scientificamerican.com/article/multiverse-the-case-for-parallel-universe/%0A
Disintegration of the universe
* In the future Degenerate Era of the universe, as space-time expands and stars burn up, all of the matter in stars will be consumed by black holes. But even black holes are not forever. Stephen Hawking theorized that black holes will slowly radiate away their mass in what is now called Hawking radiation until they too dissipate away. http://www.nytimes.com/books/first/a/adams-universe.html
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MEDIA CREDITS:
Music provided by APM
Sound effects: Freesound.org
Additional Animations:
– Galaxy within Universe: Edgeworx;
– Stars at center of Milky Way – NASA/NCSA University of Illinois Visualization by Frank Summers, Space Telescope Science Institute, Simulation by Martin White and Lars Hernquist, Harvard University
What if everything in the universe came to your doorstep…in a box?! What The Physics is BACK! Future episodes will explore the universe—but first, let’s unbox it.
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SCIENTIFIC NOTES:
Explosive young stars
* The average lifetime of a star is about 10 billion years, but the bigger the star, the shorter its life. One rare type of star, called a hypergiant, can be tens, hundreds, or even a thousand times the mass of our sun. These stars burn out and explode into supernovae in just a few million years. http://www.guide-to-the-universe.com/hypergiant-star.html
Black holes
* Black holes form from the collapse of a massive star at the end of its life, but this only happens in stars about three times as massive as the sun. http://burro.case.edu/Academics/Astr201/EndofSun.pdf
How big is the universe?
* Probably infinite. No one knows the size of the universe for sure, and we may never know, but the latest thinking is that it probably goes on forever. https://map.gsfc.nasa.gov/universe/uni_shape.html
Standard cosmological model
* According to the standard cosmological model, the universe started with a big bang, underwent rapid inflation within the first fraction of a second, and continues to expand, driven by a vacuum energy called dark energy. All of the structure we see in the universe has come from interactions between dark energy and dark matter (which accounts for about 85% of the universe’s matter). This model describes and predicts many phenomena in the universe but is not perfect. https://physics.aps.org/articles/v8/108
False vacuum model
* The false vacuum model is a real, albeit unlikely theory. All the fundamental forces of nature have corresponding fields (e.g., gravitational fields, magnetic fields, etc.), and we generally believe that the universe is at rest in a global minimum of the potentials of those fields. But if we are instead at rest in a local minimum, or a “false vacuum,” the universe could potentially be nudged, catastrophically, into a lower minimum.
Recycling stars into life
* Before the first stars, the universe was all hydrogen and helium. All heavier elements, including the building blocks of life, were forged in stars.
Dark matter and dark energy
* Only 5% of the universe is made up of matter we can see. The “missing mass” later dubbed dark matter was first noticed in the 1930s; dark energy was discovered in the 1990s. In both cases, their existence was inferred by their effect on objects they interact with. However, they are still not directly observable, so nobody knows yet what they are made of.
Leftover light from the Big Bang
* The theory of the Big Bang predicted the existence of cool radiation pervading the universe, left over from its beginning. In an accidental discovery, two New Jersey scientists discovered the cosmic microwave background, a nearly uniform bath of radiation throughout the universe at a temperature of about 3 Kelvin, or -454 degrees Fahrenheit.
Gravitational waves
* Albert Einstein predicted the existence of gravitational waves in his theory of general relativity in 1916. According to his theory, the acceleration of massive objects, like black holes, should send ripples through space-time at the speed of light. A century after his prediction, two merging black holes sent a ripple through space-time that was detected on Earth as a signal that stretched the 4-kilometer arms of a detector by less than 1/1,000 the width of a proton.
Cosmic dust
* Cosmic dust is cast off from stars at the end of their lives and hovers in galaxies as clouds. These clouds of dust absorb ultraviolet and visible light, obscuring much of what lies behind them. This makes it notoriously difficult to study things like the dusty center of our galaxy.
The observable universe
* The universe is 13.8 billion years old. Since the distance we can observe is limited by the time it takes light to travel to Earth, we can only ever observe a fraction of the universe: an expanding sphere around us that is now about 46 billion years in radius. However, the universe is much larger than what we can observe.
CREDITS:
Host, Writer, Producer: Greg Kestin
Animation & Compositing: Danielle Gustitus
Contributing Writers: Lissy Herman, HCSUCS
Filming, Writing, & Editing Contributions from:
Samia Bouzid and David Goodliffe
Creation of Sad Star Image: Drew Ganon
Special thanks:
Julia Cort
Lauren Aguirre
Ari Daniel
Anna Rothschild
Allison Eck
Fernando Becerra
And the entire NOVA team
