Brown Dwarf: Star aspirant

The international astronomical Union defines Brown dwarfs as balls of gas in space that are too small to be bona fide hydrogen burning stars, but large enough to burn deuterium which anything bigger than about 13 times. The mass of Jupiter can do because of this brown dwarfs are often called failed stars or super Jupiter’s however, there’s a major problem with this deuterium burning based definition. It doesn’t make any scientific sense first. Unlike how hydrogen Fusion is huge. Since it means you can shine brightly for millions or billions of years burning deuterium doesn’t power or effect an astronomical object in any particularly meaningful way, which is probably why you haven’t heard much about it. I mean, look at this density versus Mass plot hydrogen burning is a cut-off that clearly distinguishes stars from non hydrogen burning things. And then there’s this other cut off between gas giants and rocky planets, but deuterium burning doesn’t appear distinguishing at all. So it may seem like there’s no real distinction between things that are slightly too small to be Stars, which we call Brown Dwarfs. And gas giant planets that they’re all really the same kind of object. However, just because deuterium isn’t a good cut off doesn’t mean there aren’t other options. So let’s briefly list the features that do scientifically distinguish brown dwarf like objects from gas giant like objects and the caveat here some of these statements are still being debated within the astronomical Community, but for each one, there are at least some researchers arguing in favor of it one movement Brown dwarfs whether above or below the deuterium limit and stars appear to

Located and move in similar ways in loose clusters with other similar objects moving with roughly the same relative speeds planets on the other hand of move around stars or brown dwarfs in orbits and are much closer to the nearest star to formation Brown dwarfs and stars appear to follow the same distribution of masses suggesting. They form the same way, the gravitational collapse of a cloud of gas and dust planets appear to follow a different distribution of masses suggesting they form in their own way by accreting from the protocol. Planetary disc of gas and dust left over around a star or brown dwarf after it forms three metallicity the dust and gas left over from Star formation has higher concentrations of metal to the atmospheres of Giant Gas planets have elevated levels of metal Brown dwarfs on the other hand have around the same amount of metal as stars for the size of orbits protoplanetary disks around Stars typically don’t extend much farther than a few hundred times the distance between the Earth and the Sun so that’s about as far out as you

Planets, however, Brown dwarfs often orbit stars or other Brown dwarfs at significantly greater distances five mass ratio protoplanetary disks are pretty much never more than ten percent of the mass of their parent star. So a planet to Star Mass ratio is almost always less than 1 to 10. However, Brown dwarfs and stars regularly orbit in pairs with mass ratios much closer to one to one basically a lot of evidence points to two separate populations of objects things that form from gravitational. Occasionally collapsing clouds of gas and things that form from The Leftovers it appears in unfortunate coincidence that the overlap in these two populations is roughly at the mass where a deuterium burning becomes possible. I mean if we didn’t have any other good way to distinguish between brown dwarfs and planets sure deuterium burning might be a reasonable rule of thumb. It’s also possible as some researchers contend that there is no real clear way of distinguishing between brown dwarfs and giant planets and that they really do just exists on a spectrum but either way deuterium is more

A distraction so among those who think that the evidence suggests Brown dwarfs are different from giant planets what supposedly distinguishes them is how they formed their consequent behavior and their composition the claim is this planet. So no matter how big appeared to be the leftovers of star formation and brown dwarfs no matter how small appear to be failed Stars. They started off the same way Stars Dubai gravitationally collapsing from a cloud of dust but failed to capture enough Mass to burn hydrogen in the end. It doesn’t matter how badly Lee they failed that is it doesn’t matter if they also can’t burn deuterium what matters is that they aspired to be stars and fell short

Alien:Other-worldly, a game of Probability and Statistics

When we think of looking for extraterrestrial life, we tend to focus on earth like planets that is planets with conditions that are similar to our own life exists on Earth the logic goes so Earth-like conditions are probably a good bet to find more life and yet there are hundreds of billions of galaxies in the observable universe each with billions. If not trillions of stars and most stars have planets orbiting them. That’s roughly a million billion billion planets the enormity of this number means it’s probably safe to assume that there are Many many other planets with life even intelligent life and this together with some basic physics and fancy statistics implies. It’s more likely that species of intelligent extraterrestrials will live on habitable planets. Unlike Earth and will be unlike humans more precisely. They’ll be bigger than us and live in smaller groups on smaller planets. Now, I know it sounds crazy that with only one data point us. We can make any predictions at all about aliens. We don’t even know exist, but we can here’s how a basic Result in statistics is that there’s a big difference between the properties of a typical individual and the properties of an individual in a typical group the majority of humans for example live in countries with a population of at least a hundred and eighty million people, but the majority of countries have populations of less than six million and the majority of religious humans are members of religions with more than a billion followers while the majority of religions have fewer than a million followers and the majority of people who follow the English Premier League are fans of teams with hundreds of millions of fans like Manchester.

While most teams have just a few million fans each it doesn’t matter how many individuals you have or how you make the group’s they can be religions or fans of sports teams or the ingredients of this trail mix it is a mathematical facts that the group that the median individual belongs to will be at least as big as the medium group or simply put any time groups are not all the same size most individuals will be members of groups that are bigger than most of the other groups the takeaway is that an individual should expect to be a member of a large group not An ordinary one, if you don’t know what group you fall into like, I don’t know what my blood type is. The most likely curves to be in are the biggest ones. I’m probably owe or a positive and when it comes to intelligent life-forms, we humans don’t know what kind of goofy falling into so statistics tells us that we as individuals should expect to be members of a large group of intelligent beings. That is we should expect that our species has a higher population than most other species and just knowing that we probably have a high population tells us a lot for example individual living

Things require space to live. I mean the countries with the biggest populations tend to have large land areas. So Earth with its high population is probably bigger than most other planets with intelligent life. Similarly smaller living creatures need less space and energy per creature and accordingly tend to have higher population densities. That’s why there are way more ants on Earth than elephants so humans with our high population are probably physically smaller than most other species of intelligent life. In fact, we should expect to be abnormal among intelligent aliens when it comes to Anything that influences overall population size, like easily available energy makes it easier to maintain higher populations. So we should expect our son to be someone hotter and brighter and closer than the stars of most intelligent alien species and we should expect our atmosphere to be more transparent to Our Stars light and so on if all this sounds a bit on the specific well with just a few more simple and reasonable assumptions based on basic physics, we can be more precise researchers have predicted that the population of most intelligent alien species should be below 20 million individuals the majority of planets with intelligent.

Life should have less than 80% Committees of the earth and the individuals of most intelligent alien species should be at least as massive as polar bears. So instead of looking for nearby intelligent extraterrestrials on earth like planets the intelligent approach might be to look for habitable planets slightly smaller darker and hazier than our own in short. We should expect to be the Manchester United at the universe searching for AFC Wimbledon

Angular Momentum

Physics at its most basic is just a description of the motion of the stuff in our universe this planet goes this way that rocket goes that way except that some in fact many objects move without moving or more precisely. They move without going anywhere. I’m talking objects that spin revolve rotate pirouette orbit Circle gyrate World twirl cartwheel and so on like a planet around a star an electron in an atom or even our solar system going around the gravitational center of the Milky Way from up close. They’re certainly moving but in the grand Scheme of things that motion doesn’t take them anywhere we can still talk about it though. Just like momentum is a concept that describes how much oomph in object has when it moves in a straight line angular momentum is a way to account for how much employee objects have when they’re going in circles figuratively or literally and angular momentum is simple in theory pick a point. Any point pretend your object is moving in a circle around that point figure out how fast the object is moving along the circle never mind that it probably isn’t moving exactly along the circle and that the circle might have to change size over time to follow. The object but anyway, then multiply that speed times the size of the circle and the objects mass and there you have it angular momentum. For example, a 2 kilogram 60 centimeter diameter bicycle wheel going 20 kilometers per hour would have an angular momentum about 70 kilogram meters squared per second. Is that useful to know the reason we care about angular momentum is that if you take a bunch of objects that are interacting electromagnetically or gravitationally or whatever and Adam all of their angular momentum into one number than that total value won’t change over time unless

The objects from outside coming in messed things up. So as another example the Earth which is 150 million kilometers from the Sun orbits at 30 km/s and has a mass of six times ten to the 24th kilograms has an angular momentum of 2.7 times 10 to the 40th kilogram meters squared per second. That’s 4,000 quintillion quintillion, bicycle wheels and this angular momentum stays roughly constant over the course of the Earth’s orbit year. In and year out, but what’s amazing is that even if the sun and the rest of the solar system were to suddenly disappear the Earth would still have that same angular momentum about the point where the sun was without the Sun’s gravity the Earth. Would of course now move in a straight line requiring an ever-larger imaginary Circle as it got farther from the point where the sun used to be but as the Earth continued through space, it’s 30 kilometer per second velocity would also point less and less along the circle. So when you calculate the angular momentum the decrease in velocity would not on cancel out.

Increasing the size of so you’d always get the same answer 2.7 times 10 to the 40th kilogram meters squared per second. So even when nothing is rotating at all angular momentum is still conserved and that’s the beauty of all of physics law, It works even when you try to break it

Twin Paradox

Did you know that you could be older than your twin like years older according to Einstein’s theory of special relativity? It’s possible because time can take faster or slower depending on how you’re moving. What yeah, we’ll get back to that. But first we’re going to learn all of special relativity. Don’t worry. There are only two postulates one is that the laws of physics are the same for everyone’s perspective or frame of reference while in uniform motion so that It means that on a plane cruising at 800 kilometers per hour an object. You dropped will fall straight down just as it would if you’re stationary on the runway same physics in those two frames otherwise plane rides would get real weird. The crazy implication of this postulate is that there’s no experiment you could do to tell that you’re moving even at 800 kilometers per hour even at a

Million kilometers per hour because you can only tell you’re moving relative to something else like the clouds outside your window. The second postulate is that the vacuum speed of light is the same for all observers 300,000 kilometers per second. Let’s just pause on that for a sec. Do you know how freaky this is? It seems that if you’re flying toward me in a spaceship going close to the speed of light and you shine a laser at me. You’ll still measure that light to be going at 300,000 kilometers per second and I’ll measure the light to be going at 300,000 kilometers per second as well. So those are the only two postulates of special relativity. The speed of light is a constant and the laws of physics are the same in every inertial reference frame inertial meaning not moving or moving at a constant velocity. Basically, you’re not accelerating and when you do accelerate like when you experience turbulence,

Or during takeoff. When you pushed back into your seat. You can tell you’re moving and special relativity no longer applies. So it’s from just these two postulates that we derive an entire physical Theory and get crazy things like length contraction and time dilation and other weird quirks of physics that are real one. Such Quark is that time can take a different rates depending on how you’re moving we call this time dilation. It’s weird but it’s real. Why does it happen? Consider two frames one is you Stationary on Earth and one is your twin zooming by in a rocket. You have identical clocks. Let’s look at yours first. Each time light makes a round trip in your clock. You count by one your twin will measure the same rate on her own clock now things get weird when you watch her clock because of her sideways motion. You see that her light has to travel a longer distance for one tick. And since the speed of light is the same for all observers her round trip takes must take more time. So time actually take slower on her moving rocket according to you. Me and this is a real phenomenon. It’s not some weird Mind Trick. We don’t usually notice this though because time dilation is quite insignificant until you’re moving close to the speed of light. So now from your twins perspective you are moving there for your clock must be running slower according to your twin and because the laws of physics are the same in both of these frames yours and hers each frame is equally correct in saying the others clock is running slower. This is where the Paradox starts imagine you and your twin start.

On Earth you stay here, but your twin zooms off in a spaceship at half the speed of light turns around and comes back the whole trip takes 30 years, but you see your twins clock tick slower. So due to time dilation during the journey. She only aged 26 years four years less than you now. Here’s the Crux of the problem from your twins perspective. She was stationary and you on Earth moved away and came back. You’re the one moving at half the speed of light so your twin should see Or clock going slower and should think you are only 26 years older by the end of the trip. So yeah, that’s not possible when your twin gets back. She’s either younger or she’s older. She can’t be in a superposition of both this isn’t Quantum. So how do we solve this Paradox? Well, the answer lies in the details when your twin turns around she has to accelerate.

Which means she’s no longer in an inertial reference frame while she accelerates and so special relativity no longer applies to her. It’s not as simple as saying your twin sees you make a round trip and you see your twin make a round trip. It’s not a symmetric problem like that because when your twin accelerates we can tell the difference between the physics that might happen in those two frames see will feel the acceleration during the turn around and you will not so when she gets back she will agree with you that you are 30 and she is 26 One last question what’s happening? The clocks During the period of acceleration we still get time dilation, but we have to use a different set of rules from general relativity general relativity states that clocks run slower and accelerated reference frames. So while your twin is turning around her clock runs slower and she sees the same thing. She sees your clock running faster than hers. So you’re aging quicker. It’s during this period of acceleration that you become the older twin. Now this phenomenon of time dilation in an accelerated reference frame is related to time dilation in a gravitational field general relativity says that clocks run slower in gravitational fields. As you may have seen occur in the movie Interstellar, you can get time dilation and other strange things occurring during different forms of motion special relativity and the twin paradox are just the tip of the iceberg.

Antimatter

Pretty much everything in the universe is made out of matter the Earth, you and me stars Interstellar dust all matter by which we mean that these things are made out of electrons and quarks and very occasionally other rarer matter particles, like muons towns and neutrinos. All of these particles are at their fundamental level excitations in everywhere permeating Quantum Fields, but as the famous quote goes for every particle, There is an equal and opposite antiparticle . In the everywhere permeating Quantum field that has all of the exact same properties as that particle except opposite charge and since these anti particles are opposite excitations of the quantum field when a particle and antiparticle meet they annihilate and destroy each other which is pretty much exactly like how the equation x squares equals 4 has two solutions 2 and minus 2 with the same value but opposite sign and when they meet they annihilate. Every fundamental particle has an antiparticle. There are anti quarks antineutrino. Has anti muons and a towns and of course antielectrons though, we call them positrons since antimatter particles are essentially identical to regular matter other than the opposite charge thing. They can combine together in essentially identical ways to form antiprotons anti-atoms anti molecules and in principle anything from anti ants to antimatter horns. We can also make their really cool positronium.

It’s like hydrogen except instead of an electron orbiting a proton. It’s an electron orbiting a positron until they annihilate each other in under a nanosecond because every particle of antimatter annihilates with regular matter upon meeting. It’s really hard to make anything big out of antimatter at this point. We’re still only able to make and contain a few hundred antihydrogen atoms at one time and when a particle and antiparticle annihilate, the energy has to go somewhere which is why matter-antimatter Annihilation is have been proposed as But naturally occurring antimatter is hard to come by. So unlike a uranium fission bomb which allows us to release the bottled energy of the supernovas that forged the uranium in the first place. You’d have to put all the energy into an antimatter bomb yourself by making antimatter, which you do by agitating empty space into pairs of matter and antimatter excitations kind of like hitting zero with a hammer to get out 2 and minus 2, except instead of a hammer you use a particle accelerator or high energy photons of light photons. Incidentally have zero charge and so are their own antiparticles in the same way that zero is equal to negative zero. In fact, mathematics has always been closely tied to antimatter the mathematics of relativistic quantum mechanics predicted the existence of antimatter for years before any had ever been discovered the fact that there’s so little antimatter around in the universe to discover is both an obvious thing because if it were around it would have destroyed us a good thing because it can’t destroy us and a puzzling thing if matter and antimatter are basically identical mirror

Images of one another why did the Big Bang produced so much more matter than antimatter? No one knows but to physicists the answer matters..

The Origin of Quantum Mechanics

Where did Quantum Theory come from it started not as a crazy idea, but with a light bulb in the early 1890’s the German Bureau of Standards asked Max Planck how to make light bulbs more efficient so that they would give out the maximum light for the least electrical power. The first task Plank faced was to predict how much light a hot filament gives off.

He knew that light consists of electromagnetic waves with different colors of light carried by different frequency waves. The problem was to ensures that as much light as possible was given off by visible waves rather than ultraviolet or infrared. He tried to work out how much light of each color a hot object emits that his predictions based on electromagnetic Theory kept disagreeing with experiments instead in what he later called an act of Despair. He threw the existing Theory out the window and work backwards from experimental measurements the data pointed him to a new rule of physics. Light waves carry energy only in packets with high-frequency light consisting of large packets of energy and low frequency light consisting of small packets of energy the idea that light comes in packets or quanta may sound crazy and it was at the time but Einstein soon related it to a much more familiar problem sharing. If you want to make a kid happy give them a cookie, but if there are two kids and you only have one cookie.

Learning be able to cheer them up half as much and if there are four or eight or sixteen hundred thousand, you’re not going to make them very happy at all. If they have to share one cookie between them. In fact, if you have a room with infinitely many kids but not infinitely many cookies. If you share the cookies evenly each kid will only get an infinitesimally small crumb and none of them will be cheered up and they’ll still eat all your cookies the difference between lightweight And kids is that you can’t actually have infinitely many kids in a room, but because light waves come in all sizes, you can have arbitrarily small light waves so you can fit infinitely many into a room and then the light waves would consume all your cookies. I mean energy, in fact, all these infinitesimally waves together would have an infinite capacity to absorb energy and they’d suck all the heat out of anything you put in the room instantly freezing.

Tea in your cup or the Sun or even a supernova. Luckily. The universe doesn’t work that way because as Plank guest the tiny high frequency waves can only carry away energy and huge packets there like fussy kids who will only accept exactly 37 cookies or a hundred and sixty-two thousand cookies no more and no less because they’re so picky The High Frequency waves lose out and most of the energy is carried away in lower frequency packets that are willing to take an equal share this common average energy that the packets carry is in fact what we mean by temperature so a higher temperature just means higher average energy and thus by Planck’s rule a higher frequency of light emitted. That’s why as an object gets hotter. It glows first infrared then red yellow white hotter and hotter towards blue violet ultraviolet and so on.

Specifically Planck’s quantum theory of fussy light tells us that light bulb filaments should be heated to a temperature of about 3200 Kelvin to ensure that most of the energy is emitted as visible waves much hotter and we’d start tanning from the ultraviolet light actually quantum physics has been staring Us in the face since long before light bulbs and tanning beds. Human beings have been gazing into Fires for millennia. And with the color of the Flames spelling out Quantum all along

Soft Hair theory

Black holes. They’re weird.And a recent paper about them seems to me to be the strangest, one yet black holes might be covered in hair. So I hope you’re ready for me to get excited about space stuff. Let’s get started. So iconic theoretical physicist. Stephen Hawking may have passed away in 2018, but papers. He wrote are still coming out after his death his latest paper released in October argues that black holes might be covered in hair. What does he mean by that? We’re going to get there by the end of this blog. But first we’re going to understand what the actually a black hole is ?, I am doing a cool weird demo that shows us intuitively why you cannot escape a black hole according to Einstein’s theory of relativity. The gravity of any Given object is proportional to its density. So if an object is dense enough, then nothing that gets too close can ever escape no matter what nothing not even light can escape from an ultra dense object. So we would call that a black

You might assume that gravity is a pulling force and you’d be in good company, Sir Isaac Newton thought the same thing back in the 1600’s you noticed that when things move they tend to move straight unless a force acts on them and curves their path, of course like wind or Kick from Sir Isaac Newton, Newton been noticed that gravity also curves the path of things downwards. So he concluded that gravity must be a force Einstein thought differently. He noticed thing with an elevator. There was a moment. He realized an elevator out in space accelerating up would act the same as gravity here on Earth. Basically, there was a problem with our theory of gravity as a force. So what is gravity then? ,well Einstein wondered what if gravity Isn’t a force but the curved trajectory of a ball flying through the air is actually straight. I’m going to have to apologize in advance because the demo I’m going to show you broke my brain just a little bit pretend you live near the equator and you start walking East trying to walk a straight as possible on your initial path. You might think that you’d keep walking parallel to the equator and never hit it right? Well try testing this on a globe try it like this line up the edge of a piece of paper. So it’s parallel with a latitude line and then keep pushing it down straight to simulate. It’s your straight path and it will actually end up intersecting with the equator. What in fact if you draw the latitude line you started on on your paper and then flatten out the paper that path would look curved as well. So your path actually curves because while you may be walking straight the Earth you’re walking on is not flat no matter what all of the articles and theories in the sidebar may tell you that’s what Einstein proposed the gravity is not a force, but an object Curves in a gravitational field for the exact same reason that you’re straight walking path.

Straight gravity is what happens when you’re moving straight on a non flat thing only in the case of gravity that non-flat thing isn’t the globe. It’s space itself and time. That’s right. The fabric of the universe space-time is curved by large masses just like the earth’s surface is curved. So let’s bring it back to black holes. See they’re inescapable as an object gets denser and denser this stuff moving near it will take curvier and curvier paths and then when You get 2 black hole level dense. The path an object takes gets so curved it’ll never ever lead back out of the black hole. And then it’s Gone Forever Without a Trace. Not even a thank you note rude, except it’s not quite sure that object is completely gone. And that’s where the hair comes in now, unfortunately while a big dents fuzzy black space office sounds adorable. Stephen Hawking was only using hair as a metaphor for the stuff that gets left behind when objects fall into a black hole. Why call it hair? Well, imagine everything in space is a bunch of Guess Who characters it easy to tell them apart because either own distinguishing features and unique peer Styles black holes on the other hand only had a few decision character.

Maybe we’ll get some of a mass electric charge and angular momentum that’s always fun. If spin has other than that, they’re almost totally nondescript involves up when unique distinguishing objects, like stars stuff or Matthew McConaughey fall into a black hole and disappear leaving behind a slightly more massive, but still perfectly bald black hole everything unique about those objects is seemingly gone disappeared tooth almost as if black holes are sucking personality out of the universe depriving us of Matthew McConaughey’s beautiful lungs. But here’s the thing one of the fundamental ideas of quantum mechanics is that information cannot be destroyed it can Be changed into different forms, but it cannot be destroyed. So if black holes really are destroying distinctive information then. Are violating the fundamental laws of physics as we know them the theory of black holes has a built-in contradiction. It’s known as the black hole information Paradox. So to try and resolve this Paradox in that 2018 paper Hawking and his co-authors proposed that black holes don’t actually destroy the information of distinctive stuff that falls into them. But instead they proposed a process where the information sticks around in the universe as photons on the boundary of the black hole known as its Event Horizon. Basically as Matthew McConaughey’s falling into the black hole. He’s also depositing really low energy particles onto the black hole’s Event Horizon leaving behind a fuzzy edge of hair on a black hole. The word soft is used to describe the low energy particles to distinguish them from hard particles, which just have more energy hence a theory of black holes with soft hair. How can his collaborators think that these soft hair photons may be where the universe preserves its information from the stuff that falls into a black hole. So the information is not destroyed. It just hangs out there on the edge and that is roughly how Hawking his collaborators think that the existence of these soft hairs could solve the information paradox.

There’s of course a lot of Mass to which you are. Welcome to treat yourself to its tax season. You deserve a break kind of just to be clear. These questions are far from answered most of the research around black holes is theoretical remember We’ve only indirectly observed their existence but while theories like this the soft hair theories could help solve the information Paradox, they’re not the final say and that’s how science is done in bits and pieces that add to science as we know it and sometimes don’t I think Stephen Hawking would be honored to know that people like you are with his theories. I’m honored to be able to help keep his scholarship alive after his passing

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