Nine smallest, faintest, most compact Galaxies

The NASA/ESA Hubble Space Telescope and NASA's Spitzer Space Telescope discovered nine of the smallest, faintest, most compact galaxies ever sighted in the distant Universe. Each of these Galaxies hosts millions of stars and is a hundred to a thousand times smaller than the Milky Way.

One of the conventional models for galaxy evolution predicts that small galaxies in the early Universe evolved into the massive galaxies of today by coalescing. Nine Lego-like 'building block' galaxies initially detected by Hubble likely contributed to the construction of the Universe as we know it. “These are among the lowest mass galaxies ever directly observed in the early Universe” says Nor Pirzkal at STScI.

Hubble detected sapphire-blue stars residing within the galaxies. The youthful stars are just a few million years old and are in the process of turning light elements created shortly after the Big Bang (hydrogen and helium) into heavier elements. The stars have probably not yet begun to pollute the surrounding space with elemental products forged within their cores.

The galaxies were first identified by James Rhoads of Arizona State University, USA, and Chun Xu of the Shanghai Institute of Technical Physics, China. Three of the galaxies appear to be slightly disrupted – rather than being round they appear stretched. This is a sign that they may be interacting and merging with neighbouring galaxies to form larger, cohesive structures.

THE SKY ON GOOGLE EARTH!!!!

Finally!!!!! Google launched Sky in Google Earth 4.2. The sky button and related search bar help navigate the sky. This is an awesome tool for Astronomy lovers. All data integrated on one platform. Travel to any star, constellation, galaxy you wish. Users can navigate in various directions on a galaxy.

Download the free version from http://earth.google.com/sky/index.html

The Facts Of the Universe

History.com has this amazing Did You Know section with simple facts about the universe, and awesome footage from NASA.

Journey To A Distant Nebula

A Nebula is a diffuse mass of interstellar dust or gas or both, visible as luminous patches or areas of darkness depending on the way the mass absorbs or reflects incident radiation. Originally, the word "nebula" referred to almost any extended astronomical object (other than planets and comets). The etymological root of "nebula" means "cloud". We sometimes use the word "nebula" to refer to galaxies, various types of star clusters and various kinds of interstellar dust/gas clouds. More strictly speaking, the word "nebula" should be reserved for gas and dust clouds and not for groups of stars.

Mercury's Soft Center

By tracking a subtle wobbling of the planet Mercury as it spins about its axis, researchers using a trio of ground-based telescopes have found strong evidence that the planet has a molten core.

Careful measurements of Mercury's spin--to an accuracy of one in 100,000--reveal that the planet's interior is decoupled from its exterior, providing strong evidence of a molten core.

Astronomer Jean-Luc Margot of Cornell University, Stan Peale of the University of California, Santa Barbara, Ray Jurgens and Martin Slade of the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., and Igor Holin of the Space Research Institute in Russia report their findings in the cover story of the May 4, 2007, journal Science.

While most models for the formation of Mercury suggest the planet has an iron-rich core, many predict that the core is solid after billions of years of cooling. Others predict that small amounts of sulfur and other trace elements mixed with the iron have lowered the core's freezing point, keeping the planet's outer core from completely solidifying over that time.

While peering into the deepest interior of a planet--even our own--is difficult even with on-site technology, the ground-based telescope data collected by Margot and his colleagues provided evidence that strongly supports the latter scenario, suggesting the core is at least partially molten and may contain at least small amounts of sulfur.

The researchers used National Science Foundation's (NSF) Arecibo Observatory in Puerto Rico, part of NSF's National Astronomy and Ionosphere Center, NSF's Robert C. Byrd Green Bank Telescope in W. Va., and the NASA/JPL 70-meter antenna at Goldstone, Calif., to beam radar signals to the planet and then carefully analyze the echoes that returned.

To obtain their measurements, the astronomers compared the properties of the return signal as it struck the distributed telescope locations on Earth's surface. The amplitude of the wobbling was twice what the researchers expected for a solid planet, but on par with an object that has a solid exterior and liquid core.