metallic / iridescent bugs for @rileyram12
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A researcher was walking through a city market when he came upon a piece of dinosaur tail, encased in amber and preserved for millions of years in all its feathery glory.
Our curator of dinosaurs says it could help settle a debate over how feathers evolved in the first place.
Black holes are hard to find. Like, really hard to find. They are objects with such strong gravity that light canât 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 weâve 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.Thatâs because under the right circumstances material from the star can interact with the black hole, revealing its presence.Â
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.  Â
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.Â
In other cases, the black holeâs companion is a giant star with a strong stellar wind. This is like our Sunâs solar wind, but even more powerful. As material rushes out from the companion star, some of it is captured by the black holeâs 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 holeâs 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
Short-eared dogs or jungle dogs (Atelocynus microtis) are a unique and elusive canid species endemic to the Amazonian basin. Since short-eared dogs favor undisturbed habitats, wild sightings are rare. What is known about the species is due mostly to a semi-wild animal named Oso (bottom photo) who was the subject of a ten-year study. The species is threatened by feral dogs, habitat destruction, and diseases like rabies and distemper. (x x x x)
Oh hey. We also did a digital zine, itâs called âRaptorsâ and features artwork from Julio Lacerda, Nathan Rogers, Fabrizio De Rossi, Joschua KnĂźppe, Midiaou Diallo, and Oliver Demuth.
All proceeds go to feeding our writer Pete Buchholz, who has written thousands of words for this, so go get yourself a copy now!
Ayanami Rei by wlop