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The Road Less Traveled

@alrendriablaze / alrendriablaze.tumblr.com

Fandoms, Geeky, Alternative, Eclectic, Collector, Writer, Level 40+, 18+ Content, She/Her/He/Him. "Can't sleep so might as well hammer." "It's never only a dream." "Love is a dagger." "After the night when I wake up, I'll see what tomorrow brings."
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Our Weird and Wonderful Galaxy of Black Holes

Black holes are hard to find. Like, really hard to find. They are objects with such strong gravity that light can’t escape them, so we have to rely on clues from their surroundings to find them.

When a star weighing more than 20 times the Sun runs out of fuel, it collapses into a black hole. Scientists estimate that there are tens of millions of these black holes dotted around the Milky Way, but so far we’ve only identified a few dozen. Most of those are found with a star, each circling around the other. Another name for this kind of pair is a binary system.That’s because under the right circumstances material from the star can interact with the black hole, revealing its presence. 

The visualization above shows several of these binary systems found in our Milky Way and its neighboring galaxy. with their relative sizes and orbits to scale. The video even shows each system tilted the way we see it here from our vantage point on Earth. Of course, as our scientists gather more data about these black holes, our understanding of them may change.   

If the star and black hole orbit close enough, the black hole can pull material off of its stellar companion! As the material swirls toward the black hole, it forms a flat ring called an accretion disk. The disk gets very hot and can flare, causing bright bursts of light.

V404 Cygni, depicted above, is a binary system where a star slightly smaller than the Sun orbits a black hole 10 times its mass in just 6.5 days. The black hole distorts the shape of the star and pulls material from its surface. In 2015, V404 Cygni came out of a 25-year slumber, erupting in X-rays that were initially detected by our Swift satellite. In fact, V404 Cygni erupts every couple of decades, perhaps driven by a build-up of material in the outer parts of the accretion disk that eventually rush in. 

In other cases, the black hole’s companion is a giant star with a strong stellar wind. This is like our Sun’s solar wind, but even more powerful. As material rushes out from the companion star, some of it is captured by the black hole’s gravity, forming an accretion disk.

A famous example of a black hole powered by the wind of its companion is Cygnus X-1. In fact, it was the first object to be widely accepted as a black hole! Recent observations estimate that the black hole’s mass could be as much as 20 times that of our Sun. And its stellar companion is no slouch, either. It weighs in at about 40 times the Sun.

We know our galaxy is peppered with black holes of many sizes with an array of stellar partners, but we've only found a small fraction of them so far. Scientists will keep studying the skies to add to our black hole menagerie.

Curious to learn more about black holes? Follow NASA Universe on Twitter and Facebook to keep up with the latest from our scientists and telescopes.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

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You Are Made of Stardust

Though the billions of people on Earth may come from different areas, we share a common heritage: we are all made of stardust! From the carbon in our DNA to the calcium in our bones, nearly all of the elements in our bodies were forged in the fiery hearts and death throes of stars.

The building blocks for humans, and even our planet, wouldn’t exist if it weren’t for stars. If we could rewind the universe back almost to the very beginning, we would just see a sea of hydrogen, helium, and a tiny bit of lithium.

The first generation of stars formed from this material. There’s so much heat and pressure in a star’s core that they can fuse atoms together, forming new elements. Our DNA is made up of carbon, hydrogen, oxygen, nitrogen, and phosphorus. All those elements (except hydrogen, which has existed since shortly after the big bang) are made by stars and released into the cosmos when the stars die.

Each star comes with a limited fuel supply. When a medium-mass star runs out of fuel, it will swell up and shrug off its outer layers. Only a small, hot core called a white dwarf is left behind. The star’s cast-off debris includes elements like carbon and nitrogen. It expands out into the cosmos, possibly destined to be recycled into later generations of stars and planets. New life may be born from the ashes of stars.

Massive stars are doomed to a more violent fate. For most of their lives, stars are balanced between the outward pressure created by nuclear fusion and the inward pull of gravity. When a massive star runs out of fuel and its nuclear processes die down, it completely throws the star out of balance. The result? An explosion!

Supernova explosions create such intense conditions that even more elements can form. The oxygen we breathe and essential minerals like magnesium and potassium are flung into space by these supernovas.

Supernovas can also occur another way in binary, or double-star, systems. When a white dwarf steals material from its companion, it can throw everything off balance too and lead to another kind of cataclysmic supernova. Our Nancy Grace Roman Space Telescope will study these stellar explosions to figure out what’s speeding up the universe’s expansion

This kind of explosion creates calcium – the mineral we need most in our bodies – and trace minerals that we only need a little of, like zinc and manganese. It also produces iron, which is found in our blood and also makes up the bulk of our planet’s mass!

A supernova will either leave behind a black hole or a neutron star – the superdense core of an exploded star. When two neutron stars collide, it showers the cosmos in elements like silver, gold, iodine, uranium, and plutonium.

Some elements only come from stars indirectly. Cosmic rays are nuclei (the central parts of atoms) that have been boosted to high speed by the most energetic events in the universe. When they collide with atoms, the impact can break them apart, forming simpler elements. That’s how we get boron and beryllium – from breaking star-made atoms into smaller ones.

Half a dozen other elements are created by radioactive decay. Some elements are radioactive, which means their nuclei are unstable. They naturally break down to form simpler elements by emitting radiation and particles. That’s how we get elements like radium. The rest are made by humans in labs by slamming atoms of lighter elements together at super high speeds to form heavier ones. We can fuse together elements made by stars to create exotic, short-lived elements like seaborgium and einsteinium.

From some of the most cataclysmic events in the cosmos comes all of the beauty we see here on Earth. Life, and even our planet, wouldn’t have formed without them! But we still have lots of questions about these stellar factories. 

In 2006, our Stardust spacecraft returned to Earth containing tiny particles of interstellar dust that originated in distant stars, light-years away – the first star dust to ever be collected from space and returned for study. You can help us identify and study the composition of these tiny, elusive particles through our Stardust@Home Citizen Science project.

Our upcoming Roman Space Telescope will help us learn more about how elements were created and distributed throughout galaxies, all while exploring many other cosmic questions. Learn more about the exciting science this mission will investigate on Twitter and Facebook.

Make sure to follow us on Tumblr for your regular dose of space!

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UGC 1810: Wildly Interacting Galaxy from Hubble : What’s happening to this spiral galaxy? Although details remain uncertain, it surely has to do with an ongoing battle with its smaller galactic neighbor. The featured galaxy is labelled UGC 1810 by itself, but together with its collisional partner is known as Arp 273. The overall shape of UGC 1810 – in particular its blue outer ring – is likely a result of wild and violent gravitational interactions. This ring’s blue color is caused by massive stars that are blue hot and have formed only in the past few million years. The inner galaxy appears older, redder, and threaded with cool filamentary dust. A few bright stars appear well in the foreground, unrelated to UGC 1810, while several galaxies are visible well in the background. Arp 273 lies about 300 million light years away toward the constellation of Andromeda. Quite likely, UGC 1810 will devour its galactic sidekick over the next billion years and settle into a classic spiral form. via NASA

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