Neutron Stars – The Most Extreme Things || What If Our Sun Became a Neutron Star?

Neutron Stars – The Most Extreme Things that are not Black Holes 

Neutron stars are one of the most extreme and violent things in the universe. Giant atomic nuclei, only a few kilometers in diameter, but as massive as stars. And they owe their existence to the death of something majestic. Stars exist because of a fragile balance. The mass of millions of billions of trillions of tons of hot plasma are being pulled inwards by gravity, and squeeze material together with so much force that nuclei fuse Hydrogen fuses into helium. This releases energy which pushes against gravity and tries to escape. As long as this balance exists, stars are pretty stable. Eventually, the hydrogen will be exhausted. Medium stars, like our Sun, go through a giant phase, where they burn helium into carbon and oxygen before they eventually turn into white dwarfs. But in stars many times the mass of our Sun, things get interesting when the helium is exhausted. For a moment, the balance of pressure and radiation tips, and gravity wins, squeezing the star tighter than before. The core burns hotter and faster, while the outer layers of the star swell by hundreds of times, fusing heavier and heavier elements. Carbon burns to neon in centuries, neon to oxygen in a year, oxygen to silicon in months, and silicon to iron in a day. And then… …death. Iron is nuclear ash. It has no energy to give and cannot be fused. The fusion suddenly stops, and the balance ends. Without the outward pressure from fusion, the core is crushed by the enormous weight of the star above it. What happens now is awesome and scary. Particles, like electrons and protons, really don’t want to be near each other. But the pressure of the collapsing star is so great that electrons and protons fuse into neutrons, which then get squeezed together as tightly as in atomic nuclei. An iron ball, the size of the Earth, is squeezed into a ball of pure nuclear matter, the size of a city. But not just the core; The whole star implodes, gravity pulling the outer layers in at 25% the speed of light. This implosion bounces off the iron core, producing a shock wave that explodes outwards and catapults the rest of the star into space. This is what we call a supernova explosion, and it will outshine entire galaxies. What remains of the star is now a neutron star. Its mass is around a million times the mass of the Earth but compressed to an object about 25 kilometers wide. It’s so dense that the mass of all living humans would fit into one cubic centimeter of neutron star matter. That’s roughly a billion tons in a space the size of a sugar cube. Put another way, that’s Mount Everest in a cup of coffee. From the outside, a neutron star is unbelievably extreme. Its gravity is the strongest, outside black holes, and, if it were any denser, it would become one. Light is bent around it, meaning you can see the front and parts of the back. 

Their surfaces reach 1,000,000 degrees Celsius, compared to a measly 6,000 degrees for our Sun. Okay, let’s look inside a neutron star. Although these giant atomic nuclei are stars, in many ways, they’re also like planets, with solid crusts over a liquid core. The crust is extremely hard. The outermost layers are made of iron left over from the supernova, squeezed together in a crystal lattice, with a sea of electrons flowing through them. Going deeper, gravity squeezes nuclei closer together. We find fewer and fewer protons, as most merge to neutrons. Until we reach the base of the crust. Here, nuclei are squeezed together so hard that they start to touch. Protons and neutrons rearrange, making long cylinders or sheets, enormous nuclei with millions of protons and neutrons shaped like spaghetti and lasagna, which physicists call nuclear pasta. Nuclear pasta is so dense that it may be the strongest material in the universe, basically unbreakable. Lumps of pasta inside a neutron star can even make mountains at most a few centimeters high, but many times as massive as the Himalayas. Eventually, beneath the pasta, we reach the core. We’re not really sure what the properties of matter are when they’re squeezed this hard. Protons and neutrons might dissolve into an ocean of quarks, a so-called quark-gluon plasma. Some of those quarks might turn into strange quarks, making a sort of strange matter, with properties so extreme, that we made a whole video about it. Or, maybe they just stay protons and neutrons. No one knows for sure, and that’s why we do science. That’s all pretty heavy stuff, literally, so let’s go back out into space. When neutron stars first collapse, they begin to spin very, very fast, like a ballerina pulling her arms in. Neutron stars are celestial ballerinas, spinning many times per second. This creates pulses because their magnetic field creates a beam of radio waves, which passes every time they spin. These radio pulsars are the best-known type of neutron star. About 2,000 are known of in the Milky Way. These magnetic fields are the strongest in the universe, a quadrillion times stronger than Earth’s after they’re born. They’re called magnetars until they calm down a little. But the absolute best kind of neutron stars are friends with other neutron stars. 

  

By radiating away energy as gravitational waves, ripples in spacetime, their orbits can decay, and they can crash into and kill each other in a kilo nova explosion that spews out a lot of their guts. When they do, the conditions become so extreme that, for a moment, heavy nuclei are made again. It’s not fusion putting nuclei together this time, but heavy neutron-rich matter falling apart and reassembling. Only very recently, we’ve learned that this is probably the origin of most of the heavy elements in the universe, like gold, uranium, and platinum, and dozens more. So there now two neutron stars collapse and become a black hole, dying yet again. Not only do stars have to die to create elements, they have to die twice. Over millions of years, these atoms will mix back into the galaxy, but some of them end up in a cloud, which gravity pulls together to form stars and planets, repeating the cycle. Our solar system is one example, and the remains of those neutron stars that came before us are all around us. Our entire technological modern world was built out of the elements neutron stars made in eons past, sending these atoms on a thirteen-billion-year journey to come together and make us and our world. And that’s pretty cool. Until then, we can look at them on paper. The 12,020 Human Space Era Calendar has arrived. You can order it now until we sell out, and then never again. Visit the cloudy cities of Venus, Dyson swarm assembly on Mercury, and cross the borders of our Solar System. Shipping from the US, and from Europe for the first time, but we deliver to every country all over the world. You could also get a plushie or hoodie or poster. We have some sweet deals for you. Get it for Christmas for your friends, families, and kids, or to distract yourself from the fact that there are 100 billion billion Earth-like planets in the habitable zone of Sun-like stars in the observable universe… …and you will never visit any of them.

What If Our Sun Became a Neutron Star?

 

Stars with a much larger mass than our Sun burn out after just a few million years; in a gigantic explosion known as a supernova. Moving at the speed of light, millions of tons of plasma, neutrinos and a whole lot of light are ejected from this explosion. But there's something left behind. A neutron star is one of the strangest things in our universe. Its dimensions are pretty crazy but bear with us. The star is only 20km (13 miles)across. That's smaller than most cities! Not only that but the sheer density of this relatively tiny star is also bizarre. A single cubic centimeter of a neutron star weighs 400 million tons. But what exactly does that mean? To put it in perspective imagine every single vehicle in the United States being crushed up into just a single sugar cube. Now imagine millions of those coming together, and that's a neutron star. With dimensions like this, there would be some pretty significant implications for us if our Sun was suddenly replaced by one. Let's get this straight. 

Our Sun will never become a neutron star. Why? Because neutron stars are born from suns that are 10-20 times the size of ours. In 5 billion years, our Sun will become a red giant and then eventually a cold white dwarf which is similar to a neutron star, just much larger and much less dense. A neutron star replacing our Sun would be pretty dangerous, to say the least. A neutron star's gravitational force would be 2 billion times stronger than Earth's. This means that pretty quickly, every single planet in our solar system would be pulled towards the star and be destroyed. And it wouldn't stop there. A neutron star rotates incredibly fast, whereas our Sun rotates once every 27 days or so. A neutron star rotates over 700 times every second! This means the star would be whirling throughout space at one-fifth of the speed of light. After thousands of years, many neutron stars begin to slow down and fizzle out. But that doesn't always happen. Sometimes a neutron star meets another star. The neutron star will begin to orbit the fully formed sun and will start to feed off its atmosphere until it eventually collapses in on itself and becomes a black hole. If you happened to be in another galaxy at the time, you'd see the neutron star as a flashing light, also known as a pulsar. Discovered in 1967 by astrophysicist Jocelyn Bell, pulsars are caused by a neutron star's magnetic field. Which, no surprise, is incredibly strong. But let's hope this neutron star isn't a magnetar. What's a magnetar you ask? It's an even stronger and rarer type of neutron star. A neutron star's magnetic field may be incredibly strong, but, a magnetar's magnetic field is 1,000 times more powerful. Yeah, we weren't kidding about these numbers being a little ridiculous. The crust of this star is under a massive amount of strain. If it happens to move at all, it creates a starquake. 

Yes, this may be a super cool sounding word but don't let that fool you. These things are scary. The crust of the star would erupt in a massive explosion, causing its magnetic field to react. This would create a massive solar storm that travels across the entire galaxy. And it wouldn't just be any solar storm. It would be trillions of times stronger than anything the Sun could produce. And what would happen if Earth got hit by this massive solar storm?

Thanks for reading: Neutron Stars – The Most Extreme Things || What If Our Sun Became a Neutron Star?, Sorry, my English is bad:)