unknownskywalker:

W5 Region, Constellation Cassiopeia

Stars young and old glitter in this Spitzer Space Telescope infrared view of the W5 star-forming region. The view takes in an area of the sky equivalent to four full moons, 6,500 light-years from Earth, in one of our Milky Way’s most picturesque stellar nurseries.

• Source: NASA MSFC - Flickr

fuckyeahspace:

Astronomers can predict—with what’s thought to be great accuracy—the large-scale structure of the universe. The prediction, shown above, is made using the observable universe as a model and by factoring in things like expansion, chaos and dark forces. The purple in this picture is dark matter; the yellow is ‘normal’ matter (i.e., stars/galaxies/planets, etc.).

Source: Virgo Consortium [1,2], George Smoot via TED.

To add a bit of clarity to George Smoot’s talk:

1. The Earth is not at the center of the universe and neither is the Milky Way. He is unclear here, but he’s speaking of the observable universe.
2. His talk is not about the shape of the universe and the universe is not spherical. He is, again, speaking of the observable universe. The shape of the universe is an unanswered question in theoretical cosmology that I will never discuss here because it’s way too complicated to be understood by anyone, really, including theoretical cosmologists.

(via itsfullofstars)

unknownskywalker:

Infant stars in Serpens

Infant stars are glowing gloriously in this infrared image of the Serpens star-forming region, captured by NASA’s Spitzer Space Telescope. The Serpens star-forming region is located approximately 848 light-years away in the Serpens constellation.

The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it. A dusty disk of cosmic debris, or “protoplanetary disk,” that may eventually form planets, surrounds the infant stars.

Wisps of green throughout the image indicate the presence of carbon rich molecules called, Polycyclic Aromatic Hydrocarbons (PAHs). On Earth, PAHs can be found on charred barbecue grills and in automobile exhaust. Blue specks sprinkled throughout the image are background stars in our Milky Way Galaxy.

• Source: Spitzer Space Telescope via NASA MSFC - Flickr

Drifting through the one-horned constellation Monoceros, these dusty streamers and new born stars are part of the active Monoceros R2 star-forming region, embedded in a giant molecular cloud. The cosmic scene was recorded by the VISTA survey telescope in near-infrared light. Visible light images show dusty NGC 2170, seen here just right of center, as a complex of bluish reflection nebulae. But this penetrating near-infrared view reveals telltale signs of ongoing star formation and massive young stars otherwise hidden by the dust. Energetic winds and radiation from the hot young stars reshape the natal interstellar clouds. Close on the sky to the star-forming Orion Nebula, the Monoceros R2 region is almost twice as far away, about 2700 light-years distant. At that distance, this vista spans about 80 light-years.

Source: APOD

unknownskywalker:

Submillimeter Galaxies

Astronomers using submillimeter wavelength telescopes discovered, about a dozen years ago, the existence of a new class of very distant galaxies that their light has been traveling towards us for over ten billion years. Although today they are old, we see them as they were only a few billion years after they formed, when they and the universe were relatively young.

These galaxies were undetected in the visible but emit strongly at submillimeter wavelengths because they have an abundance of warm dust. What heats the dust is still controversial - probably either massive star formation, or an active black hole at the galactic nucleus, or perhaps both.

Our Milky Way galaxy, or at least the region where the sun resides, probably formed between seven and ten billion years ago, and so understanding these remote systems can also help us understand our own origins.

Now, astronomers from the Harvard-Smithsonian Center for Astrophysics used the Submillimeter Array (SMA) to probe the emission in two of these puzzling, luminous galaxies. The spatial resolution of the SMA allowed the team to measure the substructure of the bright cores for the first time. That structure holds the key to understanding the physical processes at work.

The luminous nuclei are most probably the result of bursts of star formation caused by a recent collision with another galaxy. Two alternative explanations that had been popular, gas-rich discs that feed active star formation or active black hole nuclei, are both less likely than interaction scenario. The SMA results and the new study’s conclusions mark an important advance in deciphering the nature of galaxies in the early universe.

Image: A pair of colliding galaxies as seen in the infrared and optical in a rare, short-lived phase of their evolution just before they merge into a single, larger galaxy.

• Source: Harvard-Smithsonian Center for Astrophysics

unknownskywalker:

What lies beneath? Magnetar enigma deepens

Observations with several NASA telescopes including Chandra, Swift, RXTE, XMM-Newton and Fermi showed that a slowly rotating neutron star with an ordinary surface magnetic field, designated SGR 0418+5729, exhibits persistent bursts of X-rays and gamma rays. The neutron star also exhibits persistent X-ray emission with regular pulsations that indicate that the star has a rotational period of 9.1 seconds. This behavior is similar to a class of neutron stars called magnetars.

This discovery may indicate the presence of an internal magnetic field much more intense than the surface magnetic field, with implications for how the most powerful magnets in the cosmos evolve.

As neutron stars rotate, the radiation of low frequency electromagnetic waves or winds of high-energy particles carry energy away from the star, causing the rotation rate of the star to gradually decrease. But after careful monitoring SGR 0418 revealed no detectable decrease in its rotation rate. This implies that the radiation of low frequency waves must be weak, and hence the surface magnetic field must be much weaker than normal.

But this raises another question: where does the energy come from to power bursts and the persistent X-ray emission from the source?

The generally accepted answer for magnetars is that the energy to power the X- and gamma-ray emission comes from an internal magnetic field that has been twisted and amplified in the turbulent interior of the neutron star, as depicted in the illustration above. Theoretical studies indicate that if the internal field becomes about ten or more times stronger than the surface field, the decay or untwisting of the field can lead to the production of steady and bursting X-ray emission through the heating of the neutron star crust or the acceleration of particles.

A crucial question is how large an imbalance can be maintained between the surface and interior fields. SGR 0418 represents an important test case. The observations already imply an imbalance of between 50 and 100. If further observations by Chandra push the surface magnetic field limit lower, then theorists may have to dig deeper for an explanation of this enigmatic object.

• Source: Chandra X-Ray Observatory

Comet Hartley 2 passing by the double star cluster in Perseus and the Heart Nebula.

Source:  APOD