Space is big! Science is cool! Let’s talk about it.
WHAT IS A SUPERNOVA?
Stars are kind of like people. They are born, live their entire lives, and then die. Except, that’s an oversimplification. Stars are giants. But they’re also giant chemical reactions.
Just like a fire, though, stars will eventually burn through their fuel supply. The difference is that when a fire exhausts its fuel, it doesn’t blow up into something multiple of its original size, nor does it collapse back on itself to form super-dense matter.
When a star “burns out,” many things can happen. But the main one is that the forces that balance out this giant object fall into an imbalance. Here’s how NASA explains it:
“Massive stars burn huge amounts of nuclear fuel at their cores or centers. This produces tons of energy, so the center gets very hot. Heat generates pressure, and the pressure created by a star’s nuclear burning also keeps that star from collapsing.
A star is in the balance between two opposite forces. The star’s gravity tries to squeeze the lead into the smallest, tightest ball possible. But the nuclear fuel burning in the star’s core creates strong outward pressure. This outward push resists the inward squeeze of gravity.
When a massive star runs out of fuel, it cools off. This causes the pressure to drop. Gravity wins out, and the star suddenly collapses. Imagine something one million times the mass of Earth collapsing in 15 seconds! The collapse happens so quickly that it creates enormous shock waves that cause the outer part of the star to explode!”
That resulting explosion is a supernova.
This composite image was assembled from 24 individual exposures taken with the NASA Hubble Space TelescopeÕs Wide Field and Planetary Camera 2 in October 1999, January 2000, and December 2000. It is one of the largest images taken by Hubble and is the highest-resolution image ever made of the entire Crab Nebula.
All that energy exploding out does a few things. It scatters the fundamental building blocks of the universe that form the core of most stars: hydrogen, helium, and carbon. The resulting cloud of debris forms a nebula.
Thus, a supernova is a part of the circle of divine life.
But, that compression from the collapse of a star also causes the core to become super dense. The resulting star core is called a white dwarf. Typically the size of Earth, a white dwarf has the same mass as a star in a much smaller package, making it incredibly dense. It does not give off light thanks to fusion, like most stars. Instead, it gives off thermal radiation that can be visible to scientists.
If the star is big enough, this super-dense core can become a black hole. Which is an entirely different post for another time.
DO THEY HAPPEN OFTEN?
Yes and no. With billions of stars across countless galaxies in our universe, there is a high probability of a star going supernova somewhere. It’s just a question of whether we can see it.
They are some of the brightest objects humans have ever observed in the night sky and are often seen in other galaxies. But supernovas are difficult to see in our own Milky Way galaxy because dust blocks our view. In 1604, Johannes Kepler discovered the last observed supernova in the Milky Way. NASA’s Chandra telescope discovered the remains of a more recent supernova. It exploded in the Milky Way more than a hundred years ago.
One of the most famous supernovae to be observed by humans was the formation of the Crab Nebula. In 1054, Chinese astronomers observed an explosion in the sky. This supernova, dubbed SN 1054, was visible for two years before fading into what we now know as the Crab Nebula.
Other cultures in Asia recorded the fantastic night explosion, but it was hundreds of years later before the work of pioneering scientists like Edwin Hubble linked the early Chinese texts to the astronomical event they observed.
In all, eight supernovae in the Milky Way have been identified thanks to written testimony through the years.
This NASA's Chandra X-ray Observatory image shows glowing material in the Cassiopeia A supernova remnant. The explosions of giant stars seed the cosmos with new chemical elements, providing the raw materials for future stars and planets.
WHAT'S LEFT BEHIND
Supernova explosions are dramatic, but the leftovers are just as interesting from a scientific point of view. These supernova remnants — including the Crab Nebula — contain information about the original system that exploded. They are also hotbeds of activity, containing powerful magnetic fields and hot plasma that can create shock waves in the surrounding material. As a result, supernova remnants are extremely important for understanding the life cycle of stars and physical processes in extreme environments.
With Type Ia supernovas, the exploding stars are completely destroyed. In the case of core-collapse supernovas, however, the remnant also harbors the neutron star or black hole created from the core of the dead star. For example, the Crab Nebula harbors a pulsar, a spinning neutron star that interacts with materials in the supernova remnant. In particular, it creates a disk of hot matter around it and a powerful jet shooting away, which heats up matter around it.
Although stars are inanimate objects, we tend to describe their stages of evolution as if they were alive. Just like us, they are born, live, and then die. Of course, their lifetimes are much longer than ours and they can ‘live’ for billions of years. And during their lives, stars produce monumental amounts of energy through nuclear processes in their interior, giving them their characteristic shine. So let’s start at the beginning. Where do stars come from? A Giant Gas Cloud A star begins life as a giant cloud of gas which is generally an accumulation of dust, gas, and plasma. Stars form inside relatively dense concentrations of interstellar gas and dust known as molecular clouds. At these temperatures, gases become molecular meaning that atoms bind together. CO and H2 are the most common molecules in interstellar gas clouds. Pillars of Creation. An interstellar cloud of gas and dust in the Eagle Nebula, known for its complexity and beauty. A Protostar Is a Baby Star A protostar look
The metaphor, analogy, theory, or reality of brains as computers? A computer is a programmable device, whether it be electrical, analogue, or quantum. Due to his dualist belief that the mind programmes the brain, Wilder Penfield said that the brain functions just like a computer. If this kind of dualism is disregarded, specifying what a brain "programme" might entail and who is authorised to "programme" the brain will be necessary in order to identify the brain to a computer. This is a metaphor if the brain "programmes" itself while it learns. This is a metaphor if evolution "programmes" the brain. In fact, the brain-computer metaphor is frequently used in the literature on neuroscience rather than as an analogy, or explicit comparison, by importing computer-related terms into discussions of the brain. For example, we claim that brains compute the locations of sounds, and we speculate about how perceptual algorithms are implemented in the brain.
Have you ever picked up your phone to aimlessly browse social media, only to find yourself sucked into a vortex of terrifying information that captures your attention but destroys your nerves? There’s a word for that: “doomscrolling.” Droomscrolling— It's not good. It’s called “doomscrolling” (or “doomsurfing”) — a portmanteau that Merriam-Webster defines as “referring to the tendency to continue to surf or scroll through bad news, even though that news is saddening, disheartening or depressing”. It's 11:37pm and the pattern shows no signs of shifting. At 1:12am, it’s more of the same. Thumb down, thumb up. Twitter, Instagram, and—if you’re feeling particularly wrought/masochistic—Facebook. Ever since the COVID-19 pandemic left a great many people locked down in their homes in early March, the evening ritual has been codifying: Each night ends the way the day began, with an endless scroll through social media in a desperate search for clarity.
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