On June 3, the ninth day since NASA’s Phoenix Mars Lander arrived at the Red Planet, the craft’s optical microscope took this composite image, the highest resolution picture of dust and sand ever acquired on Mars. The dust, kicked up by the landing, sits on circular pieces of silicone that are 3 millimeters in diameter. The silicone provides a sticky surface for holding the sand-grain-sized particles examined by the microscope.
Credit: NASA/JPL-Caltech/University of Arizona

Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy. Using infrared images from NASA's Spitzer Space Telescope, scientists have discovered that the Milky Way's elegant spiral structure is dominated by just two arms. Previously, our galaxy was thought to possess four major arms. This artist's concept illustrates the new view of the Milky Way presented in St. Louis at the 212th American Astronomical Society meeting.
Credit: NASA/JPL-Caltech

TOPOLOGICAL HARMONY Familiar relationships between sets of musical notes, such as transposition between chords, directly translate into geometrical structures such as this Möbius strip — where each dot represents a class of equivalent two-note chords — or into more complex structures. MORE
Credit: Science

Astronomers have used the radio-emitting water molecules (illustrated here), or masers, at the heart of the galaxy NGC 4258 to find a more accurate value of the Hubble constant and shed new light on dark energy. Full story
Credit: Courtesy NRAO/AUI, Artist: John Kagaya

Artist's depiction of Mars Phoenix Lander on the planet's icy northern polar region
Credit: JPL/NASA, UA

Flocks of starlings flying over Rome. Physicists used computers to track the motion of single birds in flocks of up to 4,000 starlings. Read the full story.
Credit: STARFLAG Project/INFM-CNR

With computer tracking, physicists found that each starling in a flock adjusts its trajectory to those of its six or seven neighbors, no matter how close or far they are. The technique helps the flocks stay cohesive when attacked by a predator such as a peregrine falcon — although in that case a flock will often still break up into two. Read the full story.
Credit: STARFLAG Project/INFM-CNR

More flocks of starlings’ evening acrobatics — a behavior that may be explained by the need to help other starlings navigate home to their roosting sites after a day spent roaming for food. Read the full story.
Credit: STARFLAG Project/INFM-CNR

FEELING THE PULL To the casual observer, this pair of galaxies appears completely separate, yet these far-flung entities are in the very early stages of collision. They are already affecting each other’s gravitational field. The unfurling of the left galaxy’s outer spiral arm gives a hint of this early interaction.
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, A. Evans (Univ. of Virginia, Charlottesville/NRAO/Stony Brook University)

Arp 256 can be found in Cetus, the whale constellation, 350 million light-years away. The tidal pull between these two galaxies deformed their original spiral shapes and spurred the formation of myriad blue-star clusters. The two tails in the left galaxy consist of stars, dust and gas.
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, A. Evans (Univ. of Virginia, Charlottesville/NRAO/Stony Brook University)

Nestled in the Hercules constellation 450 million light-years away, this clash of spiral galaxies is one building block of the Great Wall of clusters and superclusters, one of the largest known structure in the universe.
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, A. Evans (Univ. of Virginia, Charlottesville/NRAO/Stony Brook University)

Arp 148, also known as “Mayall’s Object,” is 500 million light-years away in the Ursa Major constellation. The collision between two parent galaxies created a shock wave that first pulled matter in and then pushed it outward to form a ring. The protruding tail is evidence of the ongoing crash.
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, A. Evans (Univ. of Virginia, Charlottesville/NRAO/Stony Brook University)

About 100 million light-years away, near the Pisces constellation, this galaxy pair formed from two disks that are still merging. The collision that began 300 million years ago is halfway done; though the two disks have fused, their nuclei remain distinct. The rust colored streaks are a train of stars.
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, A. Evans (Univ. of Virginia, Charlottesville/NRAO/Stony Brook University)