Accurate

Today's Moon Phase!

Keep track of the Moon on MoonGiant as it does it's monthly dance around the Earth

Tonight’s a New Moon!

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Goddamn

We learned about the Uyuni Salt Flat in Marine Bio this year but the teacher never showed ANYTHING like this!!! I already thought that the band was beautiful, this just makes it 10 times more so. Welp, I know what to put next on my dream vacay list.

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Night Sky Reflections from the Worlds Largest Mirror : What’s being reflected in the world’s largest mirror? Stars, galaxies, and a planet. Many of these stars are confined to the grand arch that runs across the image, an arch that is the central plane of our home Milky Way Galaxy. Inside the arch is another galaxy – the neighboring Large Magellanic Cloud (LMC). Stars that are individually visible include Antares on the far left and Sirius on the far right. The planet Jupiter shines brightly just below Antares. The featured picture is composed of 15 vertical frames taken consecutively over ten minutes from the Uyuni Salt Flat in Bolivia. Uyuni Salt Flat (Salar de Uyuni) is the largest salt flat on Earth and is so large and so extraordinarily flat that, after a rain, it can become the world’s largest mirror – spanning 130 kilometers. This expansive mirror was captured in early April reflecting each of the galaxies, stars, and planet mentioned above. via NASA

Best Star Wars movie can’t deny it

Prequels and sequels eat your heart out

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The Empire Strikes Back opened in theaters on this day in 1980.

I love supermassive black holes!!!

Expect this in the chapter about black holes lol

The relationship between SBHs and their host galaxies are so cool!

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AAS NOVA

A Young Population of Hidden Jets

By Susanna Kohler

Looking for a fireworks show this 4th of July? Try checking out the distant universe, where powerful jets flung from supermassive black holes slam into their surroundings, lighting up the sky.

Though these jets are hidden behind shrouds of gas and dust, a new study has now revealed some of these young powerhouses.

A Galaxy–Black-Hole Connection

In the turbulent centers of active galaxies (active galactic nuclei, or AGN), gas and dust rains onto supermassive black holes of millions to billions of solar masses, triggering dramatic jets that plow into the surrounding matter and light up across the electromagnetic spectrum.

The growth of a supermassive black hole is thought to be closely tied to the evolution of its host galaxy, and feedback like these jets may provide that link. As the jets collide with the gas and dust surrounding the galaxy’s nucleus, they can trigger a range of effects — from shock waves that drive star formation, to gas removal that quenches star formation.

To better understand the connections between supermassive black holes and their host galaxies, we’d especially like to observe AGN at a time known as Cosmic Noon. This period occurred around 10 billion years ago and marks a time when star formation and supermassive black hole growth was at its strongest.

The Hidden World of Cosmic Noon

But there’s a catch: around Cosmic Noon, galaxies were heavily shrouded in thick gas and dust. This obscuring material makes it difficult for us to observe these systems in short wavelengths like optical and X-ray. Instead, we have to get creative by searching for our targets at other wavelengths.

Since AGN emission is absorbed by the surrounding dust and re-radiated in infrared, we can use infrared brightness to find obscured but luminous sources. To differentiate between hidden clumps of star formation and hidden AGN, we also look for a compact radio source — a signature that points to a jet emitted from a central black hole.

A team of scientists led by Pallavi Patil (University of Virginia and the National Radio Astronomy Observatory) has now gone on the hunt for these hidden sources at Cosmic Noon.

Newly-Triggered Jets Caught in the Act

Patil and collaborators observed a sample of 155 infrared-selected sources, following up with high-resolution imaging from the Jansky Very Large Array to identify compact radio sources. From their observations and modeling of the jets, the authors estimate these sources’ properties.

The authors find bright luminosities, small sizes, and high jet pressures — all of which suggest that we’ve caught newly-triggered jets in a short-lived, unique phase of AGN evolution where the jets are still embedded in the dense gas reservoirs of their hosts. The jets are expanding slowly because they have to work hard to push through the thick clouds of surrounding material. Over time, the jets will likely expand to larger scales and clear out the surrounding matter, causing the sources to evolve into more classical looking radio galaxies.

What’s next? The authors are currently working on a companion study to further explore the shapes of the jets and their immediate environments. These young, hidden sources will provide valuable insight into how supermassive black holes evolve alongside their host galaxies.

Citation “High-resolution VLA Imaging of Obscured Quasars: Young Radio Jets Caught in a Dense ISM,” Pallavi Patil et al 2020 ApJ 896 18. doi:10.3847/1538-4357/ab9011

TOP IMAGE….Artist’s impression of a galaxy forming stars, as powerful jets that are flung from its central black hole collide with the surrounding matter. [ESO/M. Kornmesser]

CENTRE IMAGE….This composite image of Centaurus A shows an example of large-scale jets launched from an AGN, which can eventually extend far beyond the galaxy, as seen here. [ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)]

LOWER IMAGE….The redshift distribution of the authors’ sample, based on spectroscopic redshifts of 71 sources. The sources span the period of peak star formation and black hole fueling around Cosmic Noon. [Patil et al. 2020]

BOTTOM IMAGE….The JVLA 10 GHz radio continuum observations for four sources in the authors’ sample. The cyan plus symbol marks the infrared-obtained source position. The color bars indicate flux in mJy/beam. [Adapted from Patil et al. 2020]

I kinda wanna print this and put it on my wall

goddamn space is too pretty

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AE Aurigae

That’s gorgeous! 

This picture right here is why I hate light pollution

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The Galaxy Above : Have you contemplated your home galaxy lately? If your sky looked like this, perhaps you’d contemplate it more often! The featured picture is actually a composite of two images taken last month from the same location in south Brazil and with the same camera – but a few hours apart. The person in the image – also the astrophotographer – has much to see in the Milky Way Galaxy above. The central band of our home Galaxy stretches diagonally up from the lower left. This band is dotted with spectacular sights including dark nebular filaments, bright blue stars, and red nebulas. Millions of fainter and redder stars fill in the deep Galactic background. To the lower right of the Milky Way are the colorful gas and dust clouds of Rho Ophiuchus, featuring the bright orange star Antares. On this night, just above and to the right of Antares was a bright planet Jupiter. The sky is so old and so familiar that humanity has formulated many stories about it, some of which inspired this very picture. via NASA

THE LIFE OF A STAR: THE END (BUT NOT REALLY)

In our last chapter, we discussed the main-sequence stage of a star. In this chapter, we'll be discussing when the main-sequence stage ends, and what happens when it does.

        In order to live, stars are required to maintain a hydrostatic equilibrium - which is the balance between the gravitational force and the gas pressure produced from nuclear fusion within the core. If gravity were to be stronger than this pressure, the star would collapse. Likewise, if the pressure were to be stronger than gravity, the star would explode. It's the balance - the equilibrium - between these two forces which keeps a star stable. Stars contain hydrogen - their primary fuel for fusion - in their core, shell, and envelope. The heat and density in the core is the only area in a main-sequence star that has enough pressure to undergo fusion. However, what happens once hydrogen runs out in the core is where things start to get ... explosive.

        For this, we'll be having two discussions: what happens in low-mass stars, versus what happens in high-mass stars.

                                                                      ~ Low-Mass Stars ~

        Low-mass stars are classified as those less than 1.4 times the mass of the sun (NASA). While low-mass stars last a lot longer than their higher-mass counterparts, these stars will eventually have fused all of the hydrogens in their core. Because the core doesn't have enough pressure to fuse helium (as it takes more pressure and heat to fuse heavier elements than less), gas pressure stops and gravity causes the core to contract. This converts gravitational potential energy into thermal energy, which heats up the hydrogen shell until it is hot enough to begin fusing. It also produces extra energy, which overcomes gravity in small amounts and causes the star to swell up a bit. As it expands, the pressure lessens and it cools. The increased energy also causes an increase in luminosity. This is what is now called a Red Giant star (ATNF). 

        Red Giants grow a lot, averagely reaching sizes of 100 million to 1 billion kilometers in diameter, which is 100-1,000 times larger than the sun. The growth of the star causes energy to be more spread out, and so cools it down to only around 3,000 degrees Celsius (still though, pretty hot). Because energy correlates with heat, and the red part of the electromagnetic spectrum is less energized, the stars glow a reddish color. Hence, the name Red Giant. Due to the current size of the sun, we can conclude that it will eventually become a Red Giant. This could be a big problem (literally), as the sun will grow so large that it will either consume Earth or become so close that it would be too hot to live. However, this won't be happening for around 5 billion years, so there's nothing immediately to worry about (Space.com).

        As more hydrogen is fused within the shell of the Red Giant, the produced helium falls down into the core. The increased mass leads to increased pressure, which leads to increased heat. Once the temperature in the core reaches 100 K (at which point the helium produced has enough energy to overcome repulsive forces), helium begins to fuse. This process is called the Triple Alpha Process (as the helium being fused are actually alpha particles, helium-4 nuclei), where three of the helium particles combine to form carbon-12, and sometimes a fourth fuses along to form oxygen-16. Both processes release a gamma-ray photon. In low-mass stars, the Triple Alpha Process spreads so quickly that the entire helium ore is fusing in mere minutes or hours. This is, accurately called, the Helium Flash. 

        After millions of years, the helium in the core will run out. Now the core is made entirely of the products of helium fusion: carbon and oxygen nuclei. As the fusion stops, gas pressure shrinks, and gravity causes the star to contract yet again. The temperature needed to fuse carbon and oxygen is even higher, as heavier elements require more energy to fuse (because, with more protons, there's more Coulombic Repulsion). However, this temperature cannot be reached, because the gravity acting on the core is not strong enough to create enough heat. The core can burn no longer.

        The helium shell of the star begins to fuse, as gravity IS strong enough to do that. The extra energy and gas pressure created causes the star to expand even more so now. The helium shell is not dense enough to cause one single helium flash, so small flashes occur every 10,000-100,000 years (due to the energy released, this is called a thermal pulse). Radiation pressure blows away most of the outer layer of the star, which gravity is not strong enough to contain. The carbon-rich molecules form a cloud of dust which expands and cools, re-emitting light from the star at a longer wavelength (ATNF).

        But what happens after the shell is fused? We'll get back to that in Chapter 7, where we'll discuss White Dwarfs and Planetary Nebulae.

        It's also important to note that not every low-mass star needs to become a Red Giant. Stars that are smaller than half the mass of the Sun (like, Red Dwarfs) are fully convective, meaning that the surface, envelope, shell, and core of star materials all mix. Because of this mixing, there is no helium buildup in the core. This means that there is not enough pressure to fuse the helium in fully convective stars, and so they skip the contraction and expansion phases of Red Giant Stars. Instead, with no gas pressure to counteract gravity, the star collapses in on itself and forms a White Dwarf (Cosmos).

                                                                     ~ High-Mass Stars ~

         High-mass stars are classified as those more than 1.4 times the mass of the sun (NASA). High-Mass Stars, as opposed to their Low-Mass counterparts, use up their hydrogen fast, and as such have much shorter lives. Just like Low-Mass Stars, they'll eventually run out of hydrogen in both their core and their shell, and this will cause the star to contract. Their density and pressure will become so strong that the core becomes extremely hot, and helium fusion starts quickly (there is no helium flash because the process of fusion will begin slowly, rather than in "a flash"). The release of energy will cause it to expand and cool into a Red Supergiant, and will also begin the fusion of the helium shell. 

        Once all of the helium is gone, leaving carbon and oxygen nuclei, the star contracts yet again. The mass (and the gravity squeezing it into a very small space with a very large density) of a high-mass star will be enough to generate the temperatures needed for carbon fusion. This produces sodium, neon, and magnesium. The neon can also fuse with helium (whose nuclei is released in the neon fusion) to create magnesium. Once the core runs out of neon, oxygen fuses. This process keeps going, creating heavier and heavier elements, until it stops at iron. At this point, the supergiant star resembles an onion. It is layered: with the heavier elements being deeper within the star, and the lighter elements closer to the surface (ATNF).

        But what happens after the star finally gets to iron? We'll get back to that in Chapters 8, 9, and 10 - where we'll discuss Supernovae, Neutron Stars, and Black Holes.

        We’re nearing the end of our star’s life, and now it’s time to look into the many ways it can go out.

        If our first five chapters were all about life, these next five will be all about death.

First -  Chapter 1: An Introduction

Previous -  Chapter 5: A Day in the Life

Next - Chapter 7: What Goes Around, Comes Around

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INTRODUCTION TO THE LIFE OF A STAR

The yellow dwarf of our Sun is around 4.5 billion years old (NASA).

   This is nothing compared to other stars, the oldest we know of was created 13.2 billion years ago (DISCOVERY OF THE 1523-0901).  Shortly before that, it is theorized the universe was a dense ball of super hot subatomic particles, until it wasn't. 

     For some reason, possibly the amounts of pressure or even the mysterious dark energy, the universe exploded into what it is today, forming crucial atoms and molecules, and continues to expand. These molecules formed clumps and clouds of gas, which eventually collapsed by gravity and created the very first stars. 

    Stars, particularly our Sun, are very important to life and affect the void of space to a great magnitude. They can tell us so much about the early universe, form elements from their deaths, and even create black holes. But how did this come to be?

     By definition, they are "huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores." (National Geographic) And there are TONS of them. There are stars everywhere we look. In fact, Astrophysicists aren't even sure how many stars there actually ARE in the universe (Space)! That's because they're not sure if the universe is infinite - in which the number of stars would also be infinite. Even so, we may not be able to detect them all, even if the number is finite.

     But they're so much more than a definition or a number. Stars aren't just objects: they're histories. Stars have a life, they are born, fuel themselves on nuclear fusion, and when they can no longer -  there are many ways their deaths can go (in brutal, yet tantalizing ways). They form solar systems, galaxies, galaxy clusters, and might just be the life-blood of the universe. Their light acts as beacons to scientists. Stars are so crucial to us, their deaths through Supernovas form most of the elements on the Periodic Table of the Elements.

    As the brilliant cosmologist, Carl Sagan, once said: "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. We are made of star-stuff."

    And if we're made of this stuff, shouldn't we at least try to understand what it actually does?

Next - Chapter 2: Classification

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So I actually did the calculations and the surface area of Jupiter could probably fit around 11,474,491,000,000 football fields.

Okay so I googled it and the radius of Jupiter is 43,441 miles. However, I’m going to convert that into meters, which’ll make that radius a cool 69,911,513 m. Next up I’ll plug that into the surface area of a sphere formula (A= 4πr^2) which will get us approximately 6.14 x 10^16 m^2 (or roughly 61,400,000,000,000,000 m^2).

Next, I found the area of one football field to be around 5,351 m^2. Dividing the surface area of Jupiter by the surface area of one football field, we can find out how many football fields will fit onto the surface of Jupiter. And that is 1.1474491 x 10^13. Calculating that, that will be 11,474,491,000,000 football fields (11 trillion or so). Oh boy.

For comparison’s sake, the universe is estimated to have AT MOST 2 trillion galaxies! Which means that Jupiter likely could fit more football fields than the universe has galaxies. Another example, there are an estimated billion trillion stars in the observable universe. Jupiter’s football fields account for half of the stars in our observable universe.

I actually tried to find out how many football fields were in the U.S. for comparison but I still can’t find a statistic. 

But also that’s pretty hilarious xD

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No WaY

Aw, now that’s a smart kitty

Also - what’s the meaning of life and death - good question. Cat please explain lol

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Upvote me so that I can post on r/science too.