Surprising predictions part 4

 Star-Crossed Lovers: The Story of How Stars are Formed

The real tragedy of Romeo and Juliet, the star-crossed lovers of Shakespeare’s play, is that they couldn’t have met under different circumstances. The stars didn’t allow it. In Shakespeare’s time, it was believed that the stars controlled many aspects of our lives. If two people were destined to be together but born under different star signs, then the chances were slim that their romance would flourish... if it even began at all! Find out more about the fascinating tale of Romeo and Juliet and other star-crossed lovers in this infographic by WebFX.

What is a star?

A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Other stars are visible from Earth only at night, when they appear as bright points in the sky.Stars are born when dense clouds of gas and dust collapse under their own gravity. Most stars live for billions of years and eventually die, shedding their outer layers and leaving behind a compact core of helium and other elements. These may become white dwarfs, neutron stars or black holes. There may be 50 billion trillion such objects in the Milky Way galaxy alone. Astronomers often group them into constellations and identify them by name—those known as stars with many lesser lights known as planets. Yet these stars have nothing in common with the stars we see twinkling above us at night. They were born long ago and so far away that their light has taken millions of years to reach our eyes. They cannot shine without being near a huge source of energy like the sun, because nuclear fusion takes place in their cores and provides energy. The ones you can see in the sky after sunset or before sunrise are called variable stars, which means that they change brightness over time. 

The most commonly used constellation to find a certain star is Orion's Belt. The three brightest stars form a straight line across the belt of Orion's costume and make it easy to locate this constellation

Life Cycle of a Star

A star is born when a huge cloud of dust and gas collapses under its own gravity. As it contracts, the core of the star gets hotter and hotter until nuclear fusion starts and the star lights up. Once fusion starts, the star's main source of energy is hydrogen. It fuses this hydrogen into helium, producing light and heat. This heat stops the contraction, and the star becomes stable. Over time, as more and more hydrogen is used up, the core of the star gets hotter and hotter until it starts to fuse heavier elements like carbon and oxygen. This fusion produces even more light and heat, but also makes the star expand. Finally, when all the fuel in a star's core has been used up, it can no longer produce enough pressure to support itself. All that's left is a glowing ball of gas called a white dwarf. But there are two other types of stars out there - red giants and supergiants - that still have plenty of fuel left to burn. These stars will eventually blow off their outer layers, creating beautiful planetary nebulae or supernovas. After the outer layers have been blown away, what remains is either a neutron star or black hole at the center. Neutron stars pack an incredible amount of mass into a very small space. Even though they're only about 12 miles across, they can be incredibly heavy! They might weigh as much as our sun! Black holes are formed when an extremely massive star dies. When it runs out of fuel and blows off its outer layers, the remaining material collapses in on itself, forming an infinitely dense point with virtually no surface area whatsoever. Eventually, after eons pass, new clouds of dust and gas start to collapse again under their own gravity, making room for new generations of stars to form. And so the cycle begins anew. In some places, such as the Orion Nebula, you can see a whole cluster of young s TVtars beginning to shine and twinkle together in their first tentative steps toward adulthood. You'll find hundreds of these young stars in places like the Orion Nebula, along with protoplanetary disks full of raw materials, which give birth to new solar systems. Some stars live fast and die young; others last billions of years. Our own Sun probably won't last another 10 billion years before running out of fuel and dying too. Then it will turn into a Red Giant, puffing off its outer layers, before finally becoming a White Dwarf that shines for eternity as a reminder of how far we've come together. In some ways, looking up at the night sky always fills me with awe. I can barely comprehend how vast and complex everything is, but my mind boggles just trying to imagine the lives of all those countless beings throughout space and time. 

For most people, stargazing may be something you do on weekends or vacations. For me, it's part of my life because I'm a doctor working in astrophysics who studies celestial bodies every day. One of the reasons why I love studying stars is that it's a lot like studying human health. Just as doctors study various treatments and their effect on the body, astronomers study different kinds of stars and the effect their different lifespans have had on them. We can learn from both stars and patients to better understand ourselves. This is true in more than one way. For example, stars and humans are alike in that they undergo the same four stages of their lifecycle. 

1) The Birth of a Star or a Human: When you were born, you were hot and unstable like a newborn star. Luckily for you, your parents and family helped to keep you warm, safe, and healthy as you grew up. This is similar to how the supermassive stars at the center of galaxies grow. 2) Getting Older (Becoming More Mature): No matter if you're a person or a star, getting older means becoming more stable (less hot). Like stars going through core fusion as they get older, children need the stability of their home environment for physical and emotional growth.

Basic Components of a Star

Stars are massive balls of gas that fuse hydrogen atoms together to create helium. This process, known as nuclear fusion, releases energy that lights up the star and keeps it from collapsing in on itself. A star's lifetime is determined by how much fuel it has to burn; the more massive a star, the shorter its life. Once a star has used up all its fuel, it can either collapse in on itself or explode in a supernova. In the latter case, the star's death throes produce heavy elements such as iron, gold and uranium that get scattered into space. These heavy elements eventually coalesce into new stars and planets. So really, you could say that every atom in your body came from a distant exploding star! But we won't go too deep into the science... 

The most common type of star is a red dwarf. It typically ranges between one tenth and one third the size of our sun, but some might be even smaller than that. Red dwarfs don't last very long (only about six trillion years) but they will often exist for trillions of years before they finally die out. White dwarfs are also relatively small stars that have shrunken down over time due to gravity. They do not give off any light so astronomers only know they're there based on their gravitational pull. They're called white dwarfs because after a while, their outer layers cool and turn white with old age. Giant stars make up about 10% of all stars in the universe and are bright blue or white because they emit intense ultraviolet radiation like our sun does at its surface. However, giant stars do not live as long as red dwarfs since they use up their fuel quickly. Our own sun belongs to this category and will likely run out of hydrogen in 5 billion years time. When that happens, the sun will become a red giant, expand in size and engulf Mercury and Venus. Earth will be spared because it orbits far enough away from the sun. Eventually, the core of the sun collapses to form a neutron star or black hole which then starts spitting out matter leftovers as stellar winds which sweep up everything within reach including other nearby solar systems. Black holes have infinite density - one teaspoon would weigh billions of tons - so anything unlucky enough to fall inside never comes back out again. Astronomers can see the effects of black holes when looking at galaxies or clusters of galaxies through telescopes. You'll notice large distortions in images from what should normally be round shapes if you find yourself looking at an area near a black hole. In the center of a black hole, things are compressed and they move faster. This movement causes heat and friction which generates light, in particular X-rays. Near the event horizon, where objects can no longer escape the force of gravity, these X-rays are brighter and stronger. Matter that gets sucked up by a black hole usually falls right in or is torn apart as it approaches. And although many people think that black holes suck things up, they actually expel jets of high speed particles that shoot outward at nearly the speed of light. As they collide with other matter near them, these jets release energy in various forms from visible to infrared to gamma rays as well as strong magnetic fields.

The hot gases within stars provide the pressure needed to keep stars from collapsing in on themselves.

Stellar Interiors

Stars are massive balls of gas that produce their own heat and light. They're made mostly of hydrogen and helium, with a small amount of other elements like carbon, nitrogen, and oxygen. A star's interior is incredibly hot and under a lot of pressure. This pressure squeezes the star's gases together, causing them to fuse together and create new elements. This process releases a ton of energy, which is what makes stars shine so bright. These reactions also give off different types of radiation, including x-rays and gamma rays. 

The death of a star happens when it runs out of fuel for fusion in its core or when an outside force acts on it (like gravity from another nearby object). When this happens, the internal pressure starts to decrease, causing the outer layers to puff up like a balloon. 

This creates something called a planetary nebula that consists mainly of hydrogen gas. Eventually these nebulae will cool down into either white dwarfs or neutron stars. White dwarfs are dense cores of dead stars and neutron stars are usually left behind after supernovas. If they have enough mass, they can form black holes as well. 

Black holes may not be able to be seen because they only emit radiation in the form of x-rays and gamma rays but if you were close enough you would see the effects of a black hole on everything around it. Gravity from a black hole bends space time around itself making things closer to it move faster than things farther away from it. 

For example, if you were looking at two astronauts who were moving away from each other but going at the same speed, one astronaut would appear to be moving slower than the other because he’s farther away! We don't know exactly how big black holes get because we've never been able to actually observe one, but some scientists think they could get about 10 times bigger than our solar system. Other astronomers think they could get much bigger than even that - maybe even infinite in size. And there might be many more of them than we originally thought. In fact, recent research suggests there could be about 100 million black holes just within our Milky Way galaxy alone! It's still unclear whether black holes can actually collide with each other and what would happen if they did.

Stellar Atmospheres

Stars are massive balls of gas that produce their own light and heat. They're held together by their own gravity, and they're incredibly hot inside. That's because they're constantly converting hydrogen into helium in their cores through nuclear fusion. This process releases a ton of energy, which makes the star's core really hot. As the hydrogen is used up, the star starts to cool down and its outer layers expand. This causes the star to become less bright and eventually die. When it finally runs out of fuel and collapses, all the leftover material is crushed to an infinitely small point with an enormous amount of gravity. At this point, there's no more outward pressure from gases pushing against each other so everything falls inward on itself, creating a supernova explosion. After this type of explosion takes place (called Type II), the remaining material can collapse again or end up in one of two different forms: either a neutron star or black hole depending on how much mass was left over after the explosion. Neutron stars are made mostly of neutrons but can also have some protons, electrons, and even some atomic nuclei mixed in. Black holes form when all the matter has been squeezed into a tiny space. These things have such intense gravitational forces that not even light can escape them! You see, as the star gets smaller and smaller due to gravity pulling everything towards the center, it ends up being denser than anything we know of here on Earth--a few ounces would weigh as much as a mountain here! These objects still release light from their surfaces but you'll never be able to see them because you'll never be able to get close enough without being pulled in yourself. In fact, astronomers can't tell if a galaxy contains a black hole until they measure the speeds at which nearby stars orbit around it. For example, our Milky Way has at least four million black holes! 

You might think that once a star dies and becomes a black hole, then it doesn't change anymore. But you'd be wrong because black holes slowly lose mass over time due to what's called Hawking radiation. So don't worry about these cosmic giants ever running out of fuel like our sun will someday; most will just keep getting smaller until they evaporate away completely! A white dwarf is a dead star that has reached the end of its life cycle and collapsed under its own weight. It typically consists of carbon and oxygen atoms that were originally present in larger amounts during the last stages of evolution. This may sound strange, but white dwarfs are actually hotter than our Sun, with surface temperatures reaching 100,000 degrees Celsius. One theory suggests that when these stars reach 1.4 solar masses (the Chandrasekhar limit) they may turn into neutron stars instead--so every little bit counts!

Stellar Surfaces

Stars are giant balls of gas that shine brightly in the night sky. They come in all different sizes, colors, and temperatures. The surface of a star is where all the action happens. It's incredibly hot and full of nuclear fusion reactions. These reactions produce the light and energy that we see and feel when we look at a star. There are two types of reactions going on inside stars. One type produces helium atoms while the other produces heavier elements like carbon, oxygen, and iron. All these reactions release heat so a star needs to be cool enough to keep them going (without getting too hot). That's why there is a zone around stars called the stellar atmosphere. The best way to measure this distance from us is by using an astronomical unit (AU). 1 AU = about 93 million miles or 150 million kilometers. For example, the Sun is only about 93 million miles away from Earth. 

A lot of people think that if you got close enough to a star it would boil you alive but actually it wouldn't because the outer layers are cooler than we might think. But if you went any closer than what astronomers call the surface then you'd get burned up! 

Did you know that each time nuclear fusion occurs in a star it creates more neutrons? These neutrons collide with nearby nuclei and can form new elements like gold! 

Stars create all sorts of heavy metals and gases but they also give off beautiful light for hundreds or thousands of years before they die out - just like our Sun will someday do. Some stars last longer than others depending on their size, color, and temperature. Our Sun will probably last another 5 billion years or so until it dies out and turns into a white dwarf. We don't know yet how long it takes for the death of one star to lead to the birth of another.

Extra Solar Planets (Exoplanets)

Most stars form in binary systems, meaning that two stars orbit each other. As these stars gravitationally interact, they can often end up coalescing into a single star. This process is thought to be how our Sun formed. Once a star forms, it can then go on to form planets. These planets, called exoplanets, are often very different from the planets in our Solar System. For example, some exoplanets are made mostly of gas, while others are made of rock. Some exoplanets orbit their star so closely that they only take a few days to complete one orbit, while others take hundreds or even thousands of years. Despite their differences, all exoplanets have one thing in common: they were all formed by the same process that creates stars. Like a solar system’s formation and evolution, exoplanet’s formation and evolution also depend on many factors including: mass of both stars; presence of nearby interstellar clouds; interstellar medium; and the distance between both planets. 

Some speculate that any life outside Earth may actually exist around an entirely different type of sun than ours. One day we may be able to find out! 

In addition, Scientists have been looking for ways to communicate with Aliens in distant planets; they are working on a project called Active SETI, which is basically broadcasting a call for ETs (extraterrestrial beings) in several radio frequencies within deep space, hoping it reaches out there; researchers claim that at least three signals have already reached more than 25,000 light years away from earth. This is certainly something interesting, but so far no response was received from them yet (if you know what I mean). We hope and pray something like that happens some time in our lifetime as well...

A Brief History of Astronomy

Humans have been looking up at the stars for centuries, wondering what they are and how they came to be. Early astronomers believed that the stars were created by gods or were eternal objects. However, as we learned more about the universe, we realized that stars are huge balls of gas that produce their own light and heat.Stars are formed when hydrogen and helium atoms combine under immense pressure and heat. Over time, these atoms fuse together to create heavier elements like carbon and oxygen. As the star grows, it produces more and more energy, eventually leading to a supernova explosion. The vast majority of the matter from this explosion gets pushed out into space and forms new stars. Scientists believe that there is enough gas in space to create trillions upon trillions of new stars each year. 

A lot has changed since people first started exploring the heavens but one thing remains true: We’ll never stop gazing up at those twinkling lights in the sky with wonderment! 

Star formation begins when clouds of gas, dust and plasma collapse under their own gravity. This compression creates an extremely dense core that ignites nuclear fusion. As more and more atoms fuse together, they release energy in different forms such as heat, light and sound waves. Some stars produce solar flares, while others throw out matter through a stellar wind or a giant explosion known as a supernova. Once it runs out of fuel for fusion reactions, a star's life is over.

Let There Be Light!: When hydrogen fuses into helium under immense pressure and heat in its core, it releases light in different wavelengths and colors based on what elements are present. Blue stars create helium and tend to be smaller than yellow stars like our sun, which create carbon when they burn hydrogen.

Other Galaxies

It is truly a remarkable feat that our tiny planet Earth is home to some of the most complex and beautiful life forms in the known universe. We are not alone in this great expanse, however. There are an estimated 100 billion galaxies in the observable universe, each containing billions or even trillions of stars. So, how are stars formed?