Astronomy Picture of the Day: 12/04/13 - RCW120

Located approximately 4,300 light-years from Earth in the constellation of Scorpius, RCW120 (also known as Sh 2-3 or Gun 58) is an emission nebula that, to some, heavily resembles a glowing emerald in the sky.

As you can see, this is a region full of hot gas and dust, which are illuminated by the light of "O" type stars (the most massive stars currently known to exist). The ring of dust shown in this picture would not be visible like this to human eyes, but it can be seen here because it was taken in infrared by Spitzer"s infrared detectors. In the center of the ring lies several more massive "O" type stars. The stars in question tirelessly work to bombard the surrounding gas with ultraviolet radiation, thus causing the material to become ionized.

The "galactic bubble" is thought to contain the mass of at least 8 suns. Astronomers think that embedded inside of it, there lies an embryonic star currently in the process of growing. Depending on how it evolves in the coming years, it might grow to become one of the biggest and brightest stars in the galaxy. (It shouldn"t be too hard, as there is an additional 2,000 solar masses worth of gas and dust for the baby star to feed on to grow!)

This image is a three-color composite showing images of the nebula taken in infrared by two instruments on-board the Spitzer Space Telescope. RCW 120 can be found ever so slightly above the flat plane of the Milky Way.

Sources & Further Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-120413-rcw120/

Image Credit: ESA/PACS/SPIRE/HOBYS Consortia

Astronomy Picture of the Day: 11/20/13 - The Cartwheel Galaxy

There is no doubt that this is one of the most stunningly beautiful galaxies in the observable universe. This, ladies and gentlemen, is a lenticular galaxy named the "cartwheel galaxy" (which tends to look more like a Ferris wheel to my eyes, but whatever). It"s located about 400 million light-years away from Earth in the constellation of Sculptor.

This image is a false-colored composite, put together using 4 separate images taken of the region at various wavelengths. Infrared data was collected by the Spitzer Space Telescope (seen in red), ultraviolet data came from the now-defunct "Galaxy Evolution Explorer" [GALEX] (pictured in blue), x-ray information was derived from the Chandra X-ray Observatory (purple) and visible light data was gathered by the Hubble Space Telescope. The galaxy likely gets its rather unique shape from a collision with a smaller galaxy that took place several hundreds of millions of years ago.

Prior to the collision, the galaxy was probably a spiral galaxy. After the collision took place, the galaxy underwent ferocious cycles of star formation. As you can see, the outer bounds of the galaxy"s rim has several hundreds of thousands of low-mass blue stars that live short lives, before exploding as beautiful supernovae blasts -- leaving behind dense stellar cores, called neutron stars (other times, stellar-mass black holes are created).

The diameter of the galaxy is about 50,000 light-years larger than our home galaxy, the Milky Way. This particular galaxy emits a large amount of infrared energy and x-ray radiation, likely due to the unusually high number of black holes located there. Many of which have a neighboring companion star, which they cannibalize on - releasing x-rays as a result. The "spokes" connecting the outer rim of the galaxy to the central core are non-thermal radio and optical spokes.

Sources & Further Reading: http://www.fromquarkstoquasars.com/astronomy-picture-of-the-day-112013-the-cartwheel-galaxy/

Image Credit: Composite: NASA/JPL/Caltech/P.Appleton et al. X-ray: NASA/CXC/A.Wolter & G.Trinchieri et al.