Woah :o

I’m so hype for this telescope though

They say it might be able to see back to when the first stars were born - how exciting!

Eat shit Hubble telescope

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The launch of the James Webb Telescope – the successor of the Hubble Telescope – has been delayed until 2021 but damn it’s going to be awesome.

Woah :o

So, basically, like the Mission Space ride at Epcot (that one is my favoriteeeee)?

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Testing and Training on the Boeing Starliner : NASA astronaut Mike Fincke works through a check list inside a mockup of Boeing’s CST-100 Starliner during a simulation at NASA’s Johnson Space Center on Aug. 21, 2019. (via NASA)

THE LIFE OF A STAR: A STAR IS BORN

All you need to make a star is dust, gravity, and time.

        Stars form from nebulae's molecular clouds - which are "clumpy, with regions containing a wide range of densities—from a few tens of molecules (mostly hydrogen) per cubic centimetre to more than one million." Stars are only made in the densest regions - cloud cores - and larger cloud cores create more massive stars. Stars also form in associations in these cores. Cores with higher percentages of mass used only for star formation will have more stars bound together, while lower percentages will have stars drifting apart. 

        These cloud cores rotate very slowly and its mass is highly concentrated in its center - while also spinning and flattening into a disk (Britannica: Star Formation). This concentration is caused by gravity. As the mass of the clump increases - it is very cold and close to absolute zero, which increases density and causes atoms to bind together into molecules such as CO and H2 - it's gravity increases and at a certain point, it will collapse under it (Uoregon). The pressure, spinning, and compressing create kinetic energy which continues to heat the gas and increase density.

        Finally, there's the last ingredient: time. The process of these molecular clouds clumping, spinning, concentrating, and collapsing takes quite a while. From start (the cloud core-forming) to finish (the birth of a main-sequence star) - the average time is at about a cool 10 million years (yikes). Of course, this differs with density and mass, but this is the time for a typical solar-type star (StackExchange).

        The next stage in a star's life - after the nebulae - is a protostar.

        After one clump separates from the cloud core, it develops its own identity and gravity, and loose gas falls into the center. This releases more kinetic energy and heats the gas, as well as the pressure. This clump will collapse under gravity, grow in density in the center. and trap infrared light inside (causing it to become opaque) (Uoregon).

        A protostar looks like a normal star - emitting light - but it's just a baby star. Protostars' cores are not hot enough to undergo nuclear fusion and the light they emit (instead of coming from the release of photons after the fusion of atoms) comes from the heat of the protostar as it contracts under gravity. By the time this is formed, the spinning and gravity have flattened the dust and gas into a protostellar disk. The rotation also generates a magnetic field - which generates a protostellar wind - and sometimes even streams or jets of gas into space (LCO).    

        This protostar, which is not much bigger than Jupiter, continues to grow by taking in more dust and gas. The light emitted absorbs dust and is remitted over and over again, resulting in a shift to longer wavelengths and causing the protostar to emit infrared light. The growth of the star is halted as jets of material stream out from the poles - the cause of this has been unidentified, although theories suggest that strong magnetic fields and rotation "act as whirling rotary blades to fling out the nearby gas." (Britannica: Star Formation)

        The "infall" of stars stops by pressure, and the protostar becomes more stable. Eventually, the temperature grows so hot (a few million kelvins) that thermonuclear fusion begins - usually in the form of deuterium (a heavier form of hydrogen), lithium, beryllium, and boron - which radiates light and energy. This starts the pre-main-sequence star phase - also called T Tauri stars - which includes lots of surface activity in the form of flares, stellar winds, opaque circumstellar disks, and stellar jets. In this phase, the star begins to contract - it can lose almost 50% of its mass - and the more massive the star, the shorter the T Tauri phase (Uoregon).

        Eventually, when the star's core becomes hot enough (in some cases, we'll touch on this later), it will begin to fuse hydrogen. This will produce "an outward pressure that balances with the inward pressure caused by gravity, stabilizing the star." (Space.com)

        This will either create an average-sized star or a massive star.

        Nuclear fusion marks the beginning of the main sequence star. A star is born.

        But it isn't always.

        Now that we've discussed the transition from nebulae to main-sequence star, we'll be talking about what happens when hydrogen fusion doesn't occur. Those are called Brown Dwarfs.

        Brown Dwarfs are those stars that form much too small - less than 0.08 the sun's mass - and as a result, they cannot undergo hydrogen fusion (Space.com).

        Brown Dwarfs, are, bigger than planets. They are roughly between the size of Jupiter and our sun. Like protostars, brown dwarfs start by fusing deuterium, and their cores contract and increase in heat as they do so. Brown Dwarfs, however, cannot contract to the size required to heat the core enough to fuse hydrogen. Their cores are dense enough to hold themselves up with pressure. They are much colder compared to main-sequence stars, ranging from 2,800 K to 300 K (the sun is 5,800 K). They are called "Brown Dwarfs" because objects below 2,200 often cold too much and develop minerals in their atmosphere, turning a brown-red color (Britannica: Brown Dwarf).

        Once Brown Dwarfs have fused all of their deuterium, they glow infrared, and the force of gravity overcomes internal pressure (the internal force of nuclear fusion used to keep it stable) as it slowly collapses. They eventually cool down and become dark balls of gas - black dwarfs (NRAO).

        Now that we've covered how stars form - and what happens in certain cases where they are not - we'll be moving to the actual life of a star. Before we talk about the end of a star's life (arguably - my favorite part) we need to discuss main-sequence, cycles, mass, heat, pressure, structure, and more. This is to understand how a star died the way it did.

        Because - when it comes to the menu of star death - stars have a few options to choose from.

First -  Chapter 1: An Introduction

Previous -  Chapter 3: Star Nurseries

Next -  Chapter 5: A Day in the Life

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Max Planck, you absolute boss

Btw there’s always something left in physics to discover. Going from nothing left to discover to quantum theory is a huge leap though, because quantum has PLENTY to figure out.

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Oof

Okay I know that I love black holes but buddy why don’t you not come here?

I wonder if falling into a black hole would hurt? If I could choose any way to go out, it’d probably be by black holes. Might as well be killed by the love of my life.

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OJ287 is one of the largest black holes in the known universe. If it were placed at the center of our solar system, its event horizon would swallow nearly everything is our Sun’s sphere of influence. All the planets, the asteroid belt, and (obviously) us. This beast is an estimated 18 billion solar masses and drifts through the cosmos some.

Image credit: Jaime Trosper/FQTQ

Aw heck yeah let’s go

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List of extrasolar candidates for liquid water

The following list contains candidates from the list of confirmed objects that meet the following criteria:

Confirmed object orbiting within a circumstellar habitable zone of Earth mass or greater (because smaller objects may not have the gravitational means to retain water) but not a star

Has been studied for more than a year

Confirmed surface with strong evidence for it being either solid or liquid

Water vapour detected in its atmosphere

Gravitational, radio or differentation models that predict a wet stratum

55 Cancri f

With a mass half that of Saturn, 55 Cancri f is likely to be a gas giant with no solid surface. It orbits in the so-called “habitable zone,” which means that liquid water could exist on the surface of a possible moon. ]

Proxima Centauri b

Proxima Centauri b is an exoplanet orbiting in the habitable zone of the red dwarfstar Proxima Centauri, which is the closest star to the Sun and part of a triple star system. It is located about 4.2 light-years from Earth in the constellation of Centaurus, making it the closest known exoplanet to the Solar System.

Gliese 581c

Gliese 581c gained interest from astronomers because it was reported to be the first potentially Earth-like planet in the habitable zone of its star, with a temperature right for liquid water on its surface, and by extension, potentially capable of supporting extremophile forms of Earth-like life.

Gliese 667 Cc

Gliese 667 Cc is an exoplanet orbiting within the habitable zone of the red dwarf star Gliese 667 C, which is a member of the Gliese 667 triple star system, approximately 23.62 light-years away in the constellation of Scorpius.

Gliese 1214 b

Gliese 1214 b is an exoplanet that orbits the star Gliese 1214, and was discovered in December 2009. Its parent star is 48 light-years from the Sun, in the constellation Ophiuchus. As of 2017, GJ 1214 b is the most likely known candidate for being an ocean planet. For that reason, scientists have nicknamed the planet “the waterworld”.

HD 85512 b

HD 85512 b is an exoplanet orbiting HD 85512, a K-type main-sequence star approximately 36 light-years from Earth in the constellation of Vela.

Due to its mass of at least 3.6 times the mass of Earth, HD 85512 b is classified as a rocky Earth-size exoplanet (<5M⊕) and is one of the smallest exoplanets discovered to be just outside the inner edge of the habitable zone.

MOA-2007-BLG-192Lb

MOA-2007-BLG-192Lb, occasionally shortened to MOA-192 b, is an extrasolar planet approximately 3,000 light-years away in the constellation of Sagittarius. The planet was discovered orbiting the brown dwarf or low-mass star MOA-2007-BLG-192L. At a mass of approximately 3.3 times Earth, it is one of the lowest-mass extrasolar planets at the time of discovery. It was found when it caused a gravitational microlensing event on May 24, 2007, which was detected as part of the MOA-II microlensing survey at the Mount John University Observatory in New Zealand.

Kepler-22b

Kepler-22b, also known by its Kepler object of interest designation KOI-087.01, is an extrasolar planet orbiting within the habitable zone of the Sun-like star Kepler-22. It is located about 587 light-years (180 pc) from Earth in the constellation of Cygnus. source

THE LIFE OF A STAR: CLASSIFICATION

In order to understand the life of a star, we must understand star classification.

        And there are SO many different ways to classify a star.

        In star classification, understanding the relationship between color and temperature is crucial. The greater the temperature of the star, the bluer they are (at their hottest, around 50,000 degrees Celcius), while red stars are cooler (at their coolest, around 3,000 degrees Celcius). This occurs on a wide range (fun fact: stars only come in red, orange, yellow, white, and blue, because stars are approximately something called a "black body"). For example, our Sun is a yellow star with a surface temperature of 5,500 degrees Celcius (The Life of a Star).

        But why is this so? In order to understand that, I'm going to tell you about how stars live at all. This is what will determine the entire life of a star - something we'll be focusing on throughout this series. Two words: nuclear fusion.

        Nuclear fusion is "a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy." (Wikipedia) And this is where nuclear fusion gets REALLY important to stars. Throughout their lives, stars undergo nuclear fusion in their core. This is mostly in the form of fusing two or more hydrogen atoms into one or more helium atoms. This releases energy in the form of light (the pressure of nuclear fusion in the core also prevents the star from collapsing under the weight of gravity, something we'll get to later). The energy transports to the surface of the star and then radiates at an "effective temperature." (Britannica) 

        Stars are different colors due to differing amounts of energy. This is best explained by Einstein's e=mc2 or the mass-energy equivalence. In other words, the more mass something has, the more energy, and vice versa. Stars with greater mass undergo more nuclear fusion - and as such - emit more energy/temperature. And so, the bigger the star, the greater the temperature, the bluer the star; and the smaller the star, the lower the temperature, the redder the star (Universe Today). Another way to think about this is this: the hotter something is, the shorter frequency of energy it emits. Blue light has a shorter frequency than red light, and so, higher energy/temperature stars are bluer.

        Another important classification of a star is its luminosity (or the brightness, or the magnitude of the star). (The Life of a Star)

        The most famous diagram classifying stars is the Herzsprung Russell Diagram, shown in this article's picture. The x-axis of the diagram shows surface temperature, hottest left, and coolest right. The y-axis shows brightness, brighter higher, and dimmer lower. There are main groups on the diagram. 

        Most stars fall in a long band stretching diagonally, starting in the upper left corner and ending in the right lower corner, this is called the main sequence. The main sequence shows stars which mostly use their life going through nuclear fusion. This process takes up most of a star's life. Most stars which are hotter and more luminous fall in the upper left corner of the main sequence and are blue in color. Most stars that have lower-masses are cooler, and redder falls in the lower right. Yellow stars like our Sun fall in the middle. 

         The group located in the lower-left corner are smaller, fainter, and bluer (hotter) and are called White Dwarfs. These stars are a result of a star like our Sun one day running out of Hydrogen.

          The group located right above the righter's main sequence is larger, cooler, brighter, and a more orange-red or red, are called Red Giants. They are also part of the dying process of a star like our sun. Above them in the upper right corner are Red Super Giants, massive, bright, cooler, and much more luminous. To the left of the Red Super Giants are similar stars which are just hotter and bluer and are called the Blue Super Giants.

        That explains the most famous star classifying diagram. The important thing to remember is the data on the chart is not what a star will be like it's whole life. A star's position on the chart will change like our Sun will one day do.

        In a ThoughtCo. article on the Hertzsprung Russell Diagram, Carolyn Collins Petersen wrote: "One thing to keep in mind is that the H-R diagram is not an evolutionary chart. At its heart, the diagram is simply a chart of stellar characteristics at a given time in their lives (and when we observed them). It can show us what stellar type a star can become, but it doesn't necessarily predict the changes in a star." ( The Hertzsprung-Russell Diagram and the Lives of Stars)

        And this will continue to be important in the next chapters. Stars don't just stay in the same position their entire lives: they change in their color, luminosity, and temperature. In this series, we'll be tracking how stars form, live and die - all dependent on these three factors - and nuclear fusion - again - super important :)

Previous -  Chapter 1: An Introduction

Next -  Chapter 3: Star Nurseries

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I love Schrodinger’s Cat memes

I might write something on quantum mechanics in the future, so I’ll probably dedicate an entire chapter to this cat. Maybe with a week’s worth of SC memes? Who knows!

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Erwin doesn’t like that.

This basically sums it up.

Well, it doesn’t show the other things stars can be after their deaths. But it was a nice video :)

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Lookin’ Good!

I’ve been wanting to be an Astronaut for Halloween but sadly I live in Florida and the heat might suffocate me in a full suit! Perhaps a nice NASA shirt and hat and maybe a fake ID badge and I can go as a scientist :D

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Artemis Generation Spacesuit Event : Amy Ross, a spacesuit engineer at Johnson Space Center, NASA Administrator Jim Bridenstine, watch as Kristine Davis and Dustin Gohmert wear prototype spacesuits. (via NASA)