Astronomy picture of the day - 2017 July 10 - Spiral Galaxy NGC 1512: The Nuclear Ring

Spiral Galaxy NGC 1512: The Nuclear Ring 
Image Credit: NASA, ESA, Hubble, LEGUS; Acknowledgement: Judy Schmidt

Explanation: What's happening around the center of this spiral galaxy? Seen in total, NGC 1512 appears to be a barred spiral galaxy -- a type of spiral that has a straight bar of stars across its center. This bar crosses an outer ring, though, a ring not seen as it surrounds the pictured region. Featured in this Hubble Space Telescope image is an inner ring -- one that itself surrounds the nucleus of the spiral. The two rings are connected not only by a bar of bright stars but by dark lanes of dust. Inside of this inner ring, dust continues to spiral right into the very center -- possibly the location of a large black hole. The rings are bright with newly formed stars which may have been triggered by the collision of NGC 1512 with its galactic neighbor, NGC 1510.

Now, it's time to say goodbye

                    CIAO, CIAO, CIAO...

Astronomy picture of the day - 2017 July 9 - Earth at Night

Earth at Night 
Image Credit : NASA, NOAA NGDC, Suomi-NPP, Earth Observatory,
Data and Processing: Chris Elvidge and Robert Simmon

Explanation: Can you find your favorite country or city? Surprisingly, on this world-wide nightscape, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts ofSouth America, Africa, Asia, and Australia. The featured composite was created from images that were collected during cloud-free periods in April and October 2012 by the Suomi-NPP satellite, from a polar orbit about 824 kilometers above the surface, using its Visible Infrared Imaging Radiometer Suite (VIIRS).

Astronomy picture of the day - 2017 July 8 - Hidden Galaxy IC 342

Hidden Galaxy IC 342 
Credit & Copyright: T. Rector (U. Alaska Anchorage), H. Schweiker, WIYN, NOAO, AURA, NSF

Explanation: Similar in size to large, bright spiral galaxies in our neighborhood, IC 342 is a mere 10 million light-years distant in the long-necked, northern constellation Camelopardalis. A sprawling island universe, IC 342 would otherwise be a prominent galaxy in our night sky, but it is hidden from clear view and only glimpsed through the veil of stars, gas and dust clouds along the plane of our own Milky Way galaxy. Even though IC 342's light is dimmed by intervening cosmic clouds, this sharp telescopic image traces the galaxy's own obscuring dust, blue star clusters, and glowing pink star forming regions along spiral arms that wind far from the galaxy's core. IC 342 may have undergone a recent burst of star formation activity and is close enough to have gravitationally influenced the evolution of the local group of galaxies and the Milky Way.

Astronomy picture of the day - 2017 July 7 - A View Toward M106

A View Toward M106 
Image Credit & Copyright: Peter Feltoti

Explanation: Big, bright, beautiful spiral, Messier 106 dominates this cosmic vista. The two degree wide telescopic field of view looks toward the well-trained constellation Canes Venatici, near the handle of the Big Dipper. Also known as NGC 4258, M106 is about 80,000 light-years across and 23.5 million light-years away, the largest member of the Canes II galaxy group. For a far away galaxy, the distance to M106 is well-known in part because it can bedirectly measured by tracking this galaxy's remarkable maser, or microwave laser emission. Very rare but naturally occuring, the maser emission is produced by water molecules in molecular clouds orbiting its active galactic nucleus. Another prominent spiral galaxy on the scene, viewed nearly edge-on, is NGC 4217 below and right of M106. The distance to NGC 4217 is much less well-known, estimated to be about 60 million light-years.

Imagens - Monumentos de Portugal - Convento de Cristo - Tomar

É um convento fortificado construído ao longo de cinco séculos e que, por isso, resultou num intrincado complexo de edifícios de vários estilos e idades. A construção original remonta aos Templários, que aqui mantiveram a sede em Portugal dos Cavaleiros da Ordem de Cristo. O Infante D. Henrique foi um dos grão-mestres mais famosos da Ordem, que custeou as suas explorações marítimas. O Convento de Cristo foi também o local onde se formou a União Ibérica, em 1581, quando Filipe II de Espanha se tornou também reconhecido como Filipe I de Portugal.

Astronomy picture of the day - 2017 July 6 - Atlas, Daphnis, and Pan

Atlas, Daphnis, and Pan 
Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Atlas, Daphnis, and Pan are small, inner, ring moons of Saturn, shown at the same scale in this montage of images from the still Saturn-orbiting Cassini spacecraft. In fact, Daphnis was discovered in Cassini images from 2005. Atlas and Pan were first sighted in images from the Voyager 1 and 2 spacecraft. Flying saucer-shaped Atlas orbits near the outer edge of Saturn's bright A Ring while Daphnis orbits inside the A Ring's narrow Keeler Gap and Pan within the A Ring's larger Encke Gap. The curious equatorial ridges of the small ring moons could be built up by the accumulation of ring material over time. Even diminutive Daphnis makes waves in the ring material as it glides along the edge of the Keeler Gap.

Astronomy picture of the day - 2017 July 5 - Aphelion Sunrise

Aphelion Sunrise 
Image Credit & Copyright: Stephen Mudge

Explanation: On July 3rd, planet Earth reached aphelion, the farthest point in its elliptical orbit around the Sun. Each year, this day of the most distant Sun happens to occur during winter in the southern hemisphere. That's where this aphelion sunrise from 2015 was captured in a time series composite against the skyline of Brisbane, Australia. Of course, seasons for our fair planet are not determined by distance to the Sun, but by the tilt of Earth's rotational axis with respect to the ecliptic, the plane of its orbit. Fondly known as the obliquity of the ecliptic, the angle of the tilt is about 23.4 degrees from perpendicular to the orbital plane. So the most distant sunrise occurs during northern summer, when the planet's north pole is tilted toward the Sun and the north enjoys longer, warmer days.

Astronomy picture of the day - 2017 July 4 - Celestial Fireworks: Into Star Cluster Westerlund 2

Celestial Fireworks: Into Star Cluster Westerlund 2 
Visualization Credit: NASA, ESA, Hubble, J. Anderson et al. (STScI); Acknowledgment: The Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), the Westerlund 2 Science Team, and the ESO

Explanation: What if you could go right into a cluster where stars are forming? A one-minute, time-lapse, video visualization of just this has been made with 3D computer modeling of the region surrounding the star cluster Westerlund 2, based on images from the Hubble Space Telescope in visible and infrared light. Westerlund 2 spans about 10 light years across and lies about 20,000 light years distant toward the constellation of the Ship's Keel (Carina). As theillustrative animation begins, the greater Gum 29 nebula fills the screen, with the young cluster of bright stars visible in the center. Stars zip past you as you approach the cluster. Soon your imaginary ship pivots and you pass over light-year long pillars of interstellar gas and dust. Strong winds and radiation from massive young stars destroy all but the densest nearby dust clumps, leaving these pillars in their shadows -- many pointing back toward the cluster center. Last, you pass into the top of the star cluster and survey hundreds of the most massive stars known.

Astronomy picture of the day - 2017 July 3 - Mountains of Dust in the Carina Nebula

Mountains of Dust in the Carina Nebula 
Image Credit: NASA, ESA, and M. Livio (STScI)

Explanation: It's stars versus dust in the Carina Nebula and the stars are winning. More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dusty stellar nurseries in which they formed. Located in the Carina Nebula and known informally as Mystic Mountain, these pillar's appearance is dominated by the dark dust even though it is composed mostly of clear hydrogen gas. Dust pillars such as these are actually much thinner than air and only appear as mountains due to relatively small amounts of opaque interstellar dust. About 7,500 light-years distant, the featured image was taken with the Hubble Space Telescope and highlights an interior region of Carina which spans about three light years. Within a few million years, the stars will likely win out completely and the entire dust mountain will evaporate.