A Via Láctea: abril 2008

* Aglow *

Aglow
Resembling a swirling witch's cauldron of glowing vapors, the black hole-powered core of the Circinus Galaxy lies 13 million light-years away from our own.

This galaxy, designated a type 2 Seyfert, is a class of mostly spiral galaxies that have compact centers and are believed to contain massive black holes. Seyfert galaxies are themselves part of a larger class of objects called Active Galactic Nuclei or AGN. AGN have the ability to remove gas from the centers of their galaxies by blowing it out into space at phenomenal speeds.

In the center of the galaxy and within the inner starburst ring is a V-shaped structure of gas. The structure appears whitish-pink in this composite image, made up of four filters. Two filters capture the narrow lines from atomic transitions in oxygen and hydrogen; two wider filters detect green and near-infrared light. In the narrow-band filters, the V-shaped structure is very pronounced. This region, which is the projection of a three- dimensional cone extending from the nucleus to the galaxy's halo, contains gas that has been heated by radiation emitted by the accreting black hole. A "counter-cone," believed to be present, is obscured from view by dust in the galaxy's disk. Ultraviolet radiation emerging from the central source excites nearby gas causing it to glow. The excited gas is beamed into the oppositely directed cones like two giant searchlights.

Located near the plane of our own Milky Way Galaxy, the Circinus galaxy is partially hidden by intervening dust along our line of sight. As a result, the galaxy went unnoticed until about 25 years ago.

Image Credit: Credits: NASA, Andrew S. Wilson (University of Maryland); Patrick L. Shopbell (Caltech); Chris Simpson (Subaru Telescope); Thaisa Storchi-Bergmann and F. K. B. Barbosa (UFRGS, Brazil); and Martin J. Ward (University of Leicester, U.K.)

* The 'Terrible Twos' *

The 'Terrible Twos'
Young stars, like toddlers, want to start showing their independence. This Spitzer view shows a stellar version of the "terrible twos" -- the stars are beginning to move away from their formative cloud, seen in red and green. Jets can be seen coming off the young stars as they make their way into the cosmos.

Located 1,000 light-years from Earth in the constellation Perseus, the reflection nebula NGC 1333 epitomizes the beautiful chaos of a dense group of stars being born.

Credit: NASA/JPL-Caltech/R. A. Gutermuth (Harvard-Smithsonian CfA)

* Big Blue Marble *

Big Blue Marble
NASA's mission has always been to explore, to discover and to understand the world in which we live from the unique vantage point of space, and to share our newly gained perspectives with the public. That spirit of sharing remains true today as NASA operates 18 of the most advanced Earth-observing satellites ever built, helping scientists make some of the most detailed observations ever made of our world.
Image Credit: NASA

* Rhea's Rings *

Rhea's Rings
This artist's concept depicts the ring of debris that may orbit Saturn's second-largest moon, Rhea. The suggested disk of solid material is exaggerated in density here for clarity.
Due to a decrease in the number of electrons detected by NASA's Cassini spacecraft on either side of the moon, scientists suggest that rings are the likeliest cause of these electrons being blocked before they reach Cassini.
Image Credit: NASA/JPL/JHUAPL
Rea's Rings
Este conceito do artista mostra o anel de detritos que orbitam Saturno a maio de segunda maior lua, Rea. O disco de material sólido sugerido é exagerado na densidade aqui para maior clareza.
Devido a uma diminuição do número de elétrons detectados pela sonda Cassini, da NASA, em ambos os lados da lua, os cientistas sugerem que os anéis são probabilidade de causar esses elétrons sendo bloqueado antes de chegar Cassini.
Imagem Crédito: NASA / JPL / JHUAPL