Techies 25

Bubbles Within Bubbles

This infrared image shows a striking example of what is called a hierarchical bubble structure, in which one giant bubble, carved into the dust of space by massive stars, has triggered the formation of smaller bubbles. The large bubble takes up the central region of the picture while the two spawned bubbles, which can be seen in yellow, are located within its rim.

NASA's Spitzer Space Telescope took this image in infrared light. The multiple bubble family was found by volunteers participating in the Milky Way Project (see www.milkywayproject.org). This citizen science project, a part of the Zooniverse group, allows anybody with a computer and an Internet connection to help astronomers sift through Spitzer images in search of bubbles blown into the fabric of our Milky Way galaxy.

The bubbles are formed by radiation and winds from massive stars, which carve out holes within surrounding dust clouds. As the material is swept away, it is thought to sometimes trigger the formation of new massive stars, which in turn, blow their own bubbles. The images in the Milky Way project are from Spitzer's Galactic Legacy Infrared Mid-Plane Survey Extraordinaire, or Glimpse, project, which is mapping the plane of our galaxy from all directions. As of June 2013, 130 degrees of the sky have been released. The full 360-degree view, which includes the outer reaches of our galaxy located away from its center, is expected soon.

How big is our Sun compared to other stars? In a dramatic and popular video featured on YouTube, the relative sizes of planets and stars are shown from smallest to largest. The above video starts with Earth's Moon and progresses through increasingly larger planets in our Solar System. Next, the Sun is shown along as compared to many of the brighter stars in our neighborhood of the Milky Way Galaxy. Finally, some of the largest stars known spin into view. Note that the true sizes of most stars outside of the Sun and Betelgeuse are not known by direct observation, but rather inferred by measurements of their perceived brightness, temperature, and distance.

NGC 6903: The Butterfly Nebula

Image Credit: +NASA, +European Space Agency, ESA, and the Hubble SM4 ERO Team
http://apod.nasa.gov/apod/ap130607.html

The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. This sharp and colorful close-up of the dying star's nebula was recorded in 2009 by the Hubble Space Telescope's Wide Field Camera 3, installed during the final shuttle servicing mission. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. Molecular hydrogen has been detected in the hot star's dusty cosmic shroud. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius).