GALAXY PORTRAIT. An array of radio telescopes allowed the closest look yet at the Milky Way’s center, which may appear as it does in this illustration. Yellow and red depict radio emissions from Sagittarius A*, which appears to be located off-center from the black hole that is thought to reside at the galaxy’s center. Full Story
Credit: S. Doeleman, M. Weiss/CXC, S. Noble, C. Gammie, NASA

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

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)