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Niki Giannandrea
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Matter of Scale

One of the fascinating things about black holes is their scale. In principle, black holes are determined by density. If matter reaches a critical density, then it will collapse under its own weight. It’s a collapse nothing can prevent, not even the strongest repulsive forces in the nucleus of an atom.

When talking about black holes we can imagine the Sun collapsing to the size of a city, or the Earth squeezed to the size of a marble, but neither the Earth or Sun are massive enough for that to happen. Black holes occur when more massive stars explode as supernovae, or when the centers of proto-galaxies collapse into supermassive black holes.

But as strange as they are, we know black holes exist. We see evidence of them throughout the universe. But sometimes it’s fun just to sit back and take in the tremendous matters of scale that black holes represent, as seen by the video below.
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I have been selected as one of the winners of an Astrophotography Contest by the NEW International Astronomy magazine First Light Magazine. This is my winning entry, congratulations to the other winners and thanks to all at First Light!!
https://www.facebook.com/FirstLightMagazine/photos/a.1497961847137789.1073741828.1441542406113067/1516421208625186/?type=1&theater
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How HIV Destroys Immune Cells.

HIV leads to AIDS primarily because the virus destroys essential immune cells called CD4 T cells, but precisely how these cells are killed has not been clear. Two papers published simultaneously today (December 19) in Nature and Science reveal the molecular mechanisms that cause the death of most CD4 T cells in lymphoid tissues, the main reservoir for such cells, during infection.

http://goo.gl/aFiHBv

Video: This 3D medical animation shows the function of white blood cells in normal immunity. It also portrays how the human immunodeficiency virus (HIV) affects the immune system and causes acquired immunodeficiency syndrome (AIDS). Common types of antiretroviral medications used to treat HIV and AIDS are also shown.
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Stars and Dust Pillars in NGC 7822 from WISE
Image Credit: WISE, IRSA, +NASA; Processing & Copyright : Francesco Antonucci
http://apod.nasa.gov/apod/ap141201.html

Hot, young stars and cosmic pillars of gas and dust seem to crowd into NGC 7822. At the edge of a giant molecular cloud toward the northern constellation Cepheus, this glowing star forming region lies about 3,000 light-years away. Within the nebula, bright edges and complex dust sculptures dominate this detailed skyscape taken in infrared light by NASA's Wide Field Infrared Survey Explorer (WISE) satellite. The atomic emission by the cluster's gas is powered by energetic radiation from the hot stars, whose powerful winds and light also sculpt and erode the denser pillar shapes. Stars could still be forming inside the pillars by gravitational collapse, but as the pillars are eroded away, any forming stars will ultimately be cut off from their reservoir of star stuff. This field spans around 40 light-years at the estimated distance of NGC 7822.
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Earth's Greatest Hits: 20 Years of #asteroids that broke up in our atmosphere: http://go.nasa.gov/1wzbyHN
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A Sagittarius Starscape
Image Credit & Copyright: Terry Hancock (Down Under Observatory)
http://apod.nasa.gov/apod/ap140905.html

This rich starscape spans nearly 7 degrees on the sky, toward the Sagittarius spiral arm and the center of our Milky Way galaxy. A telescopic mosaic, it features well-known bright nebulae and star clusters cataloged by 18th century cosmic tourist Charles Messier. Still popular stops for skygazers M16, the Eagle (far right), and M17, the Swan (near center) nebulae are the brightest star-forming emission regions. With wingspans of 100 light-years or so, they shine with the telltale reddish glow of hydrogen atoms from over 5,000 light-years away. Colorful open star cluster M25 near the upper left edge of the scene is closer, a mere 2,000 light-years distant and about 20 light-years across. M24, also known as the Sagittarius Star Cloud, crowds in just left of center along the bottom of the frame, fainter and more distant Milky Way stars seen through a narrow window in obscuring fields of interstellar dust.
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M6: The Butterfly Cluster
Image Credit & Copyright: Marco Lorenzi
http://apod.nasa.gov/apod/ap140903.html

To some, the outline of the open cluster of stars M6 resembles a butterfly. M6, also known as NGC 6405, spans about 20 light-years and lies about 2,000 light years distant. M6, pictured above, can best be seen in a dark sky with binoculars towards the constellation of the Scorpion (Scorpius), coving about as much of the sky as the full moon. Like other open clusters, M6 is composed predominantly of young blue stars, although the brightest star is nearly orange. M6 is estimated to be about 100 million years old. Determining the distance to clusters like M6 helps astronomers calibrate the distance scale of the universe.
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