A Spider in Space

TaranutlaSeveral million young stars are vying for our attention in this image of a stellar breeding ground in 30 Doradus, located in the heart of the Tarantula Nebula. Early astronomers nicknamed the nebula because its glowing filaments resemble spider legs.

30 Doradus is the brightest star-forming region visible in the Large Magellanic Cloud, a small, satellite galaxy of our Milky Way. It’s home to the most massive stars yet found.

This composite image is one of the largest mosaics ever assembled from Hubble photos and includes multiple observations taken by Hubble‘s Wide Field Camera 3 and Advanced Camera for Surveys. The Hubble images were combined with ground-based data taken with the European Southern Observatory’s 2.2-meter telescope in La Silla, Chile.

Image Credit: NASA / ESA / ESO

Ten Years Ago

Huygens_descentThese images of Saturn’s moon Titan were taken on 14 January, 2005 by the Huygens probe at four different altitudes. The images are flattened (Mercator) projections of the view from the descent imager/spectral radiometer on the probe as it landed on Titan’s surface.

Ten years ago, Huygens parachuted into the haze of the alien moon toward an uncertain fate. After a gentle descent lasting more than two hours, it landed with a thud on a frigid floodplain surrounded by icy cobblestones. This was the first landing on a moon in the outer solar system, Titan, the largest moon of Saturn.

Image Credit: ESA / NASA

The Galactic Core

galactic coreWhen we look inward toward the center of the Milky Way, the galactic core is obscured in visible light by intervening dust clouds, but infrared light penetrates the dust. This composite false-color infrared image of the center of our galaxy reveals a new population of massive stars and new details in complex structures in the hot ionized gas swirling around the central 300 light-years.It combines the sharp imaging of the Hubble Space Telescope‘s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) with color imagery from a previous Spitzer Space Telescope survey done with its Infrared Astronomy Camera (IRAC).

In this new data astronomers now see that the massive stars are not confined to one of the three known clusters of massive stars in the Galactic Center, known as the Central cluster, the Arches cluster, and the Quintuplet cluster. These three clusters are easily seen as tight concentrations of bright, massive stars in the image. The unattached stars may have formed in isolation, or they may have originated in clusters that have been disrupted by strong gravitational tidal forces.

The winds and radiation from these stars form the complex structures seen in the core, and in some cases, they may be triggering new generations of stars. IN the upper left large arcs of ionized gas form linear filaments suggesting the influence of locally strong magnetic fields.

The lower left region shows pillars of gas sculpted by winds from hot massive stars in the Quintuplet cluster.

Near the center of the image ionized gas surrounding the supermassive black hole at the center of the galaxy is confined to a bright spiral embedded in a circum-nuclear dusty donut-shaped torus.

Image Credit: NASA / ESA

On Edge

The beautiful side of IC 335This Hubble Space Telescope image shows the galaxy IC 335 in front of a backdrop of distant galaxies. The disk of IC 335 appears edge-on from the vantage point of Earth. This makes it difficult for astronomers to classify it because most of the characteristics of a galaxy’s morphology, the arms of a spiral or the bar across the center, are only visible on its face. It’s possible that the 45,000 light-year-long galaxy could be classified as an S0 type.

Such lenticular galaxies have structure that fall between those of true spiral and of elliptical galaxies. They have a thin stellar disk and a bulge, like spiral galaxies, but unlike typical spiral galaxies, they have used up most of the interstellar medium. Only a few new stars can be created out of the material that is left and the star formation rate is very low. Hence, the population of stars in S0 galaxies consists mainly of aging stars, very similar to the star population in elliptical galaxies. Since S0 galaxies have ill-defined spiral arms, they are easily mistaken for elliptical galaxies if they are seen edge-on. Also, S0 and elliptical class galaxies share some common characteristics, like typical sizes and spectral features.

Both classes of galaxies are evolving passively. However, while elliptical galaxies may be passively evolving when we observe them, they have usually had violent interactions with other galaxies in their past.  On the other hand,  S0 galaxies are either aging and fading spiral galaxies which never had any interactions with other galaxies or they are the aging result of a single merger between two spiral galaxies in the past.

Image Credit: ESA / NASA

Comet Cliffs

cometcliffs_rosetta_960These high cliffs occur on the surface of a comet. They were discovered to be part of the dark nucleus of Comet Churyumov–Gerasimenko by Rosetta, the ESA spacecraft orbiting the comet since early August. These ragged cliffs were imaged by the spacecraft about two weeks ago. Although towering about one kilometer high, the low surface gravity of Comet CG would likely make a jump from the cliffs survivable. At the foot of the cliffs is relatively smooth terrain dotted with boulders as large as 20 meters across.

Image Credit: ESA