Space Photos This Week: Moon Mash-up, Saturn Aurora, More

A Light in the Darkness

Image courtesy NASA/JPL-Caltech/L. Pagani (Observatoire de Paris/CNRS)

Starlight bounces off a normally dark, interstellar core cloud (center) inside a larger cloud called L183 in a short-infrared-wavelength Spitzer Space Telescope image released on September 24.

At long infrared wavelengths, the core appears dark (right). (The image at left is a composite of the other two pictures.)

The luminosity of such cores at certain wavelengths—a new phenomenon called coreshine—surprised scientists, who had thought the dust particles in these star- and planet-forming regions aren't big enough to reflect light. The presence of bigger grains in a core cloud, Spitzer scientists say, suggests the cloud is relatively old and that it hosts faster-forming planets.

Published September 30, 2010

Pinhole Portrait

Image courtesy ESO/R. Fosbury/T. Trygg/D. Rabanus

The sun crosses the sky roughly 180 times in an extremely long-exposure "solargraph" released by the Chile-based European Southern Observatory (ESO) on September 22.

The photograph was made between mid-December 2009 and mid-June 2010 with a pinhole camera—in this case a punctured black-plastic film canister, aluminum foil, and black-and-white film.

The resulting picture highlights the clear skies that make the ESO's high-desert Chajnantor site so attractive to astronomers. The scant spots of darkness in the solar trails show how uncommon clouds are above the future site of the Atacama Large Millimeter/submillimeter Array (ALMA).

Published September 30, 2010

Alien's-Eye View

Image courtesy NASA/Goddard/Marc Kuchner and Christopher Stark

NASA supercomputer simulations released September 23 suggest what our solar system may look like to an alien using infrared technology now—and millions of years ago.

Today (top left), for example, the gravity of the gas giant Neptune creates gaps by tugging at the icy dust and debris of the Kuiper belt, which orbits just beyond the planets. Long ago, though, infrared images would have showed a brighter Kuiper, due to the presence of more debris—and more collisions—the model suggests.

Published September 30, 2010

Mooned?

Image courtesy NASA/JPL/Space Science Institute

Two of Saturn's moons appear to form a conjoined world in an image from NASA's Cassini orbiter released September 24.

The double-moon effect is aided by the matching reflectivity of Dione (top), which is closer to the camera, and Rhea, which is farther away but slightly larger than Dione. The strategic alignment of a large, faint crater at the "bottom" edge of Dione completes the astronomical illusion.

(Also see "Saturn Moon Loses Its Rings, Gains a Mystery.")

Published September 30, 2010