What did the first quasars look like? The nearest quasars
are now known to be supermassive black holes in the centers of galaxies. Gas and dust that falls toward a quasar glows brightly,
sometimes outglowing the entire home galaxy. The quasars that formed in the first billion years of the universe are more mysterious,
though, with even the nature of the surrounding gas still unknown. Above, an artist's impression shows a primordial quasar
as it might have been, surrounded by sheets of gas, dust, stars, and early star clusters. Exacting observations of three distant
quasars now indicate emission of very specific colors of the element iron. These Hubble Space Telescope observations, which
bolster recent results from the WMAP mission, indicate that a whole complete cycle of stars was born, created this iron, and
died within the first few hundred million years of the universe.
Stars seem to arc through southern skies in this surrealistic time
exposure -- recorded before moonrise from the Gemini South Observatory, Cerro Pachon, Chile, Planet Earth. During the one
hour 40 minute exposure camera and tripod were fixed, so the concentric star trails are a reflection of Earth's daily rotation
about its axis. The view looks to the south and includes the Gemini telescope enclosure in the foreground. At the apparent
center of the curving trails, the South Celestial Pole lies just off the upper left edge. Two faint, wide streaks track the
Magellanic Clouds, satellites of the Milky Way Galaxy, while a meteor flashes throught the scene just left of the observatory.
Where does dust collect in galaxies? To help find out, a team of
researchers took the most detailed image ever of gas clouds and dust in the neighboring Large Magellanic Cloud (LMC) galaxy.
The composite image, shown above, was taken by the Spitzer Space Telescope in infrared light, which highlights the natural
glow of the warm materials returned to the interstellar medium by stars. The above mosaic combines 300,000 individual pointings
to create a composite 1,000-times sharper than any previous LMC image. Visible are vast clouds of gas and dust, showing in
graphic detail that dust prefers regions near young stars (red-tinted bright clouds), scattered unevenly between the stars
(green-tinted clouds), and in shells around old stars (small red dots). Also visible are huge caverns cleared away by the
energetic outflows of massive former stars. The faint blue (false-color) glow across the bottom is the combined light from
the old stars in the central bar of the LMC. The LMC is a satellite galaxy to our own Milky Way Galaxy, spans about 70,000
light years, and lies about 160,000 light years away toward the southern constellation of the Swordfish (Dorado).
One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark,
molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s.
The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis.
The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow
to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's
base are young stars just in the process of forming. Light takes about 1500 years to reach us from the Horsehead Nebula. The
above image was taken with the 0.9-meter telescope at Kitt Peak National Observatory.