Stars

This is about how stars die. Stars die when their nuclear fuel runs out. So if you want to know all about star deaths, this is the article for you. Let’s get started! How Stars Die Throughout all human history, we gaze up at a beautiful canvas of thousands of stars.  In fact, these are a mere fraction of the stars in just our Milky Way galaxy alone.  Mythologies, artwork, games, and everything else include stars. But, have you ever wondered, “how do stars die?”  Actually, we only need to understand two simple things to learn about star death. Nuclear Energy – Pushing Out Deep inside every star, scorching heat and crushing density make for a seriously wild place. Even atomic particles do some funny things under such conditions. For instance, hydrogen atoms zip around so wildly, they smash into each other and combine to form heavier helium atoms. But, with all of this newly-gained extra energy, atoms feel unstable. And, they don’t like that.  Therefore, atoms now release extra energy to become stable once again. Finally, this released energy pushes outward from the star. Gravity – Pulling In Everything in our universe has mass.  In other words, everything is made of stuff.  Plus, the more stuff something is made of, the more gravity it has, or the more it can pull everything else in towards itself. For instance, gravity is why we have our Moon.  Earth’s large mass gives our planet strong gravity, which keeps the much less massive Moon locked in orbit. However, stars are on a whole new level. In fact, our Sun makes up over 99% of our entire solar system’s mass.  Seriously, think about that again. All planets, comets, asteroids, and everything else only make up less than one percent of the solar system.  The rest is our gigantic Sun.  Not to mention, our Sun is considered a rather average and unimpressively sized star. Because of this, stars have truly unimaginable gravity. They are able to hold large planets and even other stars in orbit with their powerful gravity.  Stars’ gravity is even strong enough to crash in, completely crushing itself. Then, why don’t all stars crush themselves instantly? Stars – a Perfect Balance As mentioned above, nuclear energy constantly pushes outward from a star. However, the stars’ powerful gravity is constantly trying to crush inward on itself. Ultimately, this inward-outward balance of gravity and energy is how all stars stay alive.  In fact, some stars will successfully hold this delicate balance for billions or even trillions of years. Even our Sun will keep itself balanced for another 5 billion years. But, eventually, atoms will no longer smash together to release nuclear energy.  Finally, stars will run out of nuclear fuel. In other words, they no longer push outward. However, gravity’s strong pull never stops.  Ultimately, without nuclear energy pushing out, nothing balances gravity anymore, and the star will come crashing in on itself. So now, the star dies. Several things may happen next, depending on various factors, like a star’s size. While we will not get into these in this article, they include: Turning into a black hole Becoming a neutron star Shrinking into a white dwarf star So How Do Stars Die? All stars have a truly poetic balance of pushing in and pushing out. Their strong nuclear energy pushes outward. Their own powerful gravity pushes inward. But, while stars maintain this balance for billions or trillions of years, it eventually stops. Ultimately, nuclear fuel runs out.  Finally, without anything stopping it, the star’s own gravity crashes in, crushing the star to death.

This is about that humans are made out of stars. It’s all from collapsing stars. So if you want to learn how it comes that humans are made of star stuff, then you’re in the right place. Let’s get right into it! All Humans Are Made Out of Stars The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. Carl Sagan Carl Sagan was, as always, correct. We, humans, are all made from stars.  That may sound like a pop music lyric or something a hippie would say, but it’s absolutely true.  Here’s the logic: #1 Star Fuel Stars’ (like our sun) run on fuel, just like our cars run on gasoline.  Star fuel is made by combining atoms. The extremely hot temperatures inside of a star make atoms move around very wildly and quickly.  The atoms move so quickly that they smash into each other and combine to form heavier elements. This process is called nuclear fusion.  Hydrogen atoms combine to form Helium atoms, Helium atoms combine to form Lithium, and so on.  Now, when our cars run out of gas, they simply stop moving. But, when a star runs out of fuel, it can no longer fight its own powerful gravity and collapse on itself.  The star’s outer shell collapses in on its core, and it explodes violently. We call this a Supernova. #2 Spread Out When this explosion happens, most of the elements that the star has created are blown out into the atmosphere.  All of these random elements spread out aimlessly in all directions and become things like planets, or galaxies, or … people. You see, since the very beginning of the universe, stars have been continually born, died, and reborn again. This endless cycle is what created everything we know in our universe.  And, since stars have been around for over 13 billion years, compared to humans’ 200 thousand year existence, they are like our ancestors. The next time you gaze up into the night sky, just think, one of those stars you see might have produced the elements that your body is made of.  You are, indeed, made of star-stuff.

This is whether all stars are born in pairs. If so, where’s the Sun’s twin? So if you want to know all about the theory that all stars have a twin star, then you’re in the right place. Without further ado, let’s do this! How Stars Are Born Every star forms deep in a molecular cloud.  Basically, areas of the cloud begin collecting more and more mass, causing incredibly dense lumps.  Ultimately, overpowered by its own newfound mass, gravity, and density, it collapses, and nuclear fusion ignites.  Now, stars, like our own Sun, are born! Are All Stars Born With a Twin? UC Berkley and Harvard evidence paints an unexpected new storyline in star birth.  Fully understanding stellar birth proves difficult, as only radio telescopes can see through thick molecular clouds.  Astronomers did just that, using the Very Large Array (VLA) to gaze deep into a molecular cloud in Perseus.  Using the resulting data, the team examined infant stars inside, like eggs. Surprisingly, the astronomers found that essentially all binary stars were only a few hundred thousand years old (the equivalent of an infant newborn in human terms).  Plus, most older stars were single.  Finally, older stars still in binary systems were found extremely close together. Great, what does this mean? Indeed, this indicates that nearly all stars are born with a twin, only to be separated at very early ages, hence the single elders.  Furthermore, this shows that older, more developed stars that remain binary pairs likely result from being pushed close together, permanently locked in one another’s gravity. If All Stars Are Born in Pairs, Where’s the Sun’s Twin? Naturally, this raises the question, “where is our twin, then?”  Our Sun likely had a twin sister, separated soon after the twins’ birth.  Now, our sibling is likely somewhere else entirely in our Milky Way galaxy. Occasionally, we experience such large-scale, almost poetic gestures from the universe.  Almost similar to emotional or biological experiences felt at our human level. But, these universal vulnerabilities remind we are interconnected with Nature.

These are 10 fascinating facts about Polaris, the so-called North Star. From that Polaris won’t be the North Star forever to that it’s 2,500 times brighter than the Sun. So if you want to learn 10 fascinating facts about Polaris, then you’re in the right place. Let’s dig right in! About 10 Polaris Facts Similar to Hollywood, the night sky is loaded with stars. And, some stars are more famous than others.  Polaris, known formally as Alpha Ursae Minoris, is possibly the most famous star.  Now, you may know this star more commonly as the “north star.” But, you may not know all of the interesting facts this bright hydrogen factory has to offer. #1 Polaris Really Is the North Star Our Earth spins on an axis. And, Earth’s north axis points out, 2.5-quadrillion-miles away to Polaris.  Because of this, Polaris always stays fixed directly to the North of our night sky.  Actually, Polaris has been our north star, or “pole star,” for thousands of years. #2 Polaris Won’t Always Be the North Star Spin a toy top, and you will notice that it spins in a wobbling cone-like shape.  Earth spins in a similar shape along its axis. But, Earth is huge!  Due to its massive size, it takes nearly 26,000 years to complete one axis spin. So, Polaris is currently on a 26,000-year reign of the north star title. #3 Winner of Best and Brightest Polaris is the brightest star in the constellation Ursa Minor, Latin for “lesser bear.”  You might recognize Ursa Minor more easily as the little dipper.  However, the little dipper, while quite recognizable, is not a true constellation. We call these almost-constellations asterisms. #4 The THREE North Stars? Polaris is not simply a single star. Rather, it is a complex system containing three stars.  Polaris A (alpha), circled by two smaller, dimmer companions locked in the massive star’s gravity, is the brightest by far. #5 Separated Siblings The Polaris system (mentioned above in #7) contains three stars, Polaris A, Polaris Ab, and Polaris B.  Now, when we hear “system,” we naturally think of close-knit objects. However, space is vast.  Actually, Polaris A’s closest neighbor, Polaris Ab sits 2-billion-miles away. And, the third star, Polaris B orbits 240-billion-miles away. #6 Wait, the FIVE North Stars!? As mentioned in #7, our north star, Polaris, is actually a three-star system.  However, recent observations indicate that two more distant stars may be part of the Polaris system’s gravity.  And, if confirmed, we technically have not one but five north stars. #7 Before Google Maps, There Was Polaris Earth’s axis has been pointed directly at Polaris for around 2,000 years.  Although only seen from the northern hemisphere, the star has been a universal guide for centuries.  Past civilizations have relied on- and survived because of its precise location. Thanks, Polaris! #8 There Is No “South Star” Coincidentally, Earth is currently pointed directly at Polaris. Now, Earth, of course, does have a southern side to its axis.  However, there are currently no stars in its crosshairs. But, one star, known as Sigma Octans, lies one degree from such a location. So, it is likely that in the future, a south star will emerge. #9 Far Brighter Than Our Sun Even at a staggering 433 light-years, Polaris shines bright in our sky at magnitude 1.97. Actually, the north star is 2,500 times brighter than our own star, the Sun.  If Polaris were our solar system’s star, the radiation and brightness would be so intense that most complex life could not exist.  Fortunately, its drastic distance makes it a brilliant compass, not a lethal weapon. #10 The Closest Cepheid Variable to Earth Cepheid variable stars pulsate at fixed rates. And, as they pulsate, their diameter changes, often by millions of miles.  And, even at its extreme cosmic distance of 433 light-years, Polaris is currently the closest cepheid variable to Earth.  Plus, this star type is commonly used to calculate distances by observing their change in brightness accurately. So once again, Polaris serves as a fantastic space navigator! FAQ – Polaris’ Location as Seen From Earth We’ve received several questions/comments pertaining to Polaris’ location, as seen from Earth.  Primarily, people wonder why Polaris is the “North Star,” yet, it tends to appear mid-sky, as opposed to directly above.This is a fantastic question.  I, personally, long-pondered the very same thing. You see, Polaris is precisely aligned with the northern point of Earth’s axis.  Plus, Earth’s axis is not always directly “north” from where you are. This is very important to keep in mind.  From the North Pole, Polaris would appear at a neck-straining 90º, because Earth’s axis points directly above.  However, from lower longitudes, like the US, you are at different angles in relation to Earth’s axis. So, Polaris will actually appear at more mid-sky altitudes, usually between 30-40º. When we are not directly aligned from the North Pole, Earth itself obstructs our view of Polaris. As shown in the diagram below, being at latitudes closer to the equator allow more shallow-angled views of the north star. Polaris is over 2.5 quadrillion miles away, so moving mere thousands of miles on Earth should not make a difference, right? But, actually, it makes a tremendous difference. Geometry does not change, nor care where we are. Overall, viewing the north star from lower longitudes will always cause it to appear lower in the sky.