This natural color composite photo of Saturn was taken by NASA’s Cassini spacecraft. (NASA)

A baby Adélie penguin nuzzles up to its mother inside one of three bird colonies on Ross Island near Antarctica. (Penguinscience.com)

This is Robonaut 2-R2, the first dexterous humanoid robot in space, in an image taken inside the International Space Station.  NASA astronaut Kevin Ford’s reflection can be seen on R2′s helmet visor. (NASA)

Lava from a lava pond, below the peak, flows on the north side of Hawaii’s Kilauea volcano. (USGS)

Photo illustration of the magnificent spiral galaxy M106, assembled using data from the Hubble Space Telescope. (NASA)

This photograph, taken through a microscope, is of a brown fat cell (brown adipocyte) taken from a muscle stem cell. (Alessandra Pasut, Ottawa Hospital Research Institute)

Technicians prepare NASA’s Landsat Data Continuity Mission (LDCM) satellite for its scheduled launch on Monday, Feb. 11 at 1800 UTC. (NASA)

Sockeye salmon migrate from salt water to fresh water in British Columbia’s Fraser River, changing from their silvery ocean colors to red in fresh water. (Tom Quinn, University of Washington)

The Orion nebula is showcased in this sweeping image from NASA’s Wide-field Infrared Survey Explorer (WISE). (NASA)

An Atlas V rocket carrying NASA’s Tracking and Data Relay Satellite-K (TDRS-K) streaks past a building at the Kennedy Space Center in Florida. (NASA)

Artist’s concept of a new view of the Milky Way. Scientists have discovered the Milky Way’s elegant spiral structure is dominated by two arms wrapping off the ends of a central bar of stars. Our galaxy was previously thought to possess four major arms. (NASA)

Native to Madagascar, this is an indri, one of the largest living lemurs in the world. (Meredith Barrett)

This is a Spallation Neutron Source cavity assembly in the clean room the Thomas Jefferson National Accelerator Facility in Virginia. It’s a piece of a particle accelerator scientists use to provide the most intense pulsed neutron beams in the world. (Jefferson Lab)

NASA will use this spacecraft, seen here with its solar panels deployed  in a clean room at Lockheed Martin in Sunnyvale, California, for its Interface Region Imaging Spectrograph (IRIS) mission scheduled for launch this April. (Lockheed Martin)

Immune system cells, called macrophages, normally engulf and kill intruding bacteria but sometimes the microbes, shown in red, find a way to escape into the interior of the cell where it can multiply and invade other cells. (Miao lab, UNC School of Medicine)

A large male purple marsh crab (Sesarma reticulatum) clips cordgrass with its claws. These crabs are nocturnal and typically live in burrows during the day to stay moist and avoid predators. (Tyler Coverdale)

This is a single five-minute exposure taken recently in Buenos Aires on an Argentinian summer night. It shows not only Earth clouds but starry clouds, the pinkish glow of the Carina Nebula and Small Magellanic Clouds. The line arcing from the center of the right side to the lower left is the orbiting International Space Station. (Photo & Copyright: Luis Argerich)

Before workers with NASA’s US Antarctic Program are sent into the field, they must first undergo training to endure the harsh Antarctic conditions. Here’s a look at their training camp site, set up on the Ross Ice Shelf ,the largest ice shelf of Antarctica. ( NASA)

Found in the waters surrounding the Philippines, a moray eel poses for a photo. (M. J. Costello)

Astronauts on the International Space Station recently used a digital camera to capture several hundred photographs of the Aurora Australis, or the “southern lights.”  (Photo: NASA)

A research team from the University at Buffalo in New York, studying glaciers at Ayr Lake on Baffin Island, Canada, found the island’s glaciers reacted rapidly to past climate change, providing what they say is a rare glimpse into glacier sensitivity to climate events. (Photo: Jason Briner via NSF)

The lava lake in the Halemaʻumaʻu crater of Hawaii’s Kīlauea volcano spits and sputters with occasional bursts of volcanic material. (Photo: USGS)

Two galaxies becoming one. This is a Hubble telescope photo of NGC 2623, two galaxies in the final stages of a titanic galaxy merger, located some 300 million light-years away. (Photo: NASA)

NASA’s Small Multi-Purpose Research Facility ( SMiRF ) evaluates the performance of thermal protection systems required to provide long-term storage and transfer of cryogenic propellants in space. Recent testing was done over a range of temperatures as low as -253°C and tank pressures from 20-80 psia (pounds per square inch absolute). (Photo: NASA & Bridget R. Caswell (Wyle Information Systems, LLC))

The Soyuz rocket carrying ISS Expedition 33 crew members launches to the International Space Station from the Baikonur Cosmodrome in Kazakhstan, on Tuesday, Oct. 23, 2012. (Photo: NASA)

Paragorga arborea, also known as bubblegum coral, is an abundant coral species that can grow massive colonies, and has been found at polar, subpolar, and subtropical regions of all of the world’s oceans. It can reach up to eight meters in height and live up to 100 years.  (Photo: NOAA/MBARI)

A look at the center of our galaxy. Using a massive nine-gigapixel image, (from the VISTA infrared survey telescope at ESO’s Paranal Observatory in Chile) an international team of astronomers has created a catalog of more than 84 million stars located in the central parts of the Milky Way. The image is so large that, if printed with the resolution of a typical book, it would be 9 meters long and 7 meters tall. (Photo: ESO/VVV Consortium/Ignacio Toledo)

This is a robot at the US Department of Energy’s Lawrence Berkeley National Laboratory that has been coded with PaR-PaR, which stands for Programming a Robot; a simple, high-level, biology-friendly, robot-programming language that allows researchers to make better use of liquid-handling robots and thereby make possible experiments that otherwise might not have been considered. (Photo: Roy Kaltschmidt, Berkeley Lab)

A bright particle of material found in a hole dug by the Curiosity Martian rover caused a bit of concern at NASA’s Jet Propulsion Laboratory because another similar object, found nearby, was identified as a piece of debris from the spacecraft. However, the mission’s science team assessed the bright particles in this scooped pit to be native Martian material rather than spacecraft debris. (Photo: NASA)

NASA/Goddard physicist Babak Saif checks an oscilloscope as he works on a project that would be capable of detecting, with atomic-level precision, gravitational waves that were predicted in Einstein’s general theory of relativity. (Photo: NASA)

A composite of a mosaic of images of Saturn and its moon, Titan, taken by NASA’s Cassini spacecraft. Seasons have changed on Saturn, the azure blue in the planet’s northern hemisphere is now fading while the southern hemisphere is now taking on a bluish hue. Scientists say these changes are likely due to the reduced intensity of ultraviolet light and the haze it produces in the southern hemisphere as winter approaches, and the increasing intensity of ultraviolet light and haze production in the northern hemisphere as summer approaches. (Photo: NASA)

The Soyuz TMA-04M spacecraft, carrying two cosmonauts and a NASA flight engineer, lands in a remote area near the town of Arkalyk, Kazakhstan, on Sept. 17, 2012. (Photo: NASA)

NASA Flight Engineer Joe Acaba signs the side of the Soyuz TMA-04M spacecraft which brought him and his crew mates back to Earth on Sept. 17, 2012. Acaba, along with Gennady Padalka and Sergei Revin of Russia, returned from four months on board the International Space Station where they served as members of the Expedition 31 and 32 crews. (Photo: NASA)

A giraffe calf, which was recently born at the Dickerson Park Zoo in Springfield, Missouri, with its mother. (Photo: Dickerson Park Zoo)

With the Martian landscape in the background, this is the Mars Hand Lens Imager (MAHLI), one of 17 cameras on NASA’s Curiosity rover. The photo was taken by the rover’s Mast Camera – MastCam (Photo: NASA)

The Heat Island Group at Lawrence Berkeley National Laboratory works to cool buildings, cities, and the planet by making roofs, pavements, and cars cooler in the sun. Here, Jordan Woods takes measurements of new cooler pavement coating. Other sample pavement coatings can be seen behind him. (Photo: Lawrence Berkeley National Laboratory)

Opportunity, a rover which has been on Mars since January 2004, captured this image of little spheres that scientists nicknamed ‘blueberries.’ These puzzling little objects were found on an outcrop of rock called “Kirkwood” and each is about 3 millimeters in diameter. (Photo: NASA)

An extreme close up of a wild tomato’s trichomes, hair-like protrusions that produce a mixture of special chemicals which shape the interactions between the plant and its environment, some of which act as the first line of defense against pests. (Photo: Michigan State University)

Shown above are the spiral galaxies NGC 3788 (top) and NGC 3786 (bottom) in the constellation Ursa Major (home of the Big Dipper). These two galaxies, like many found throughout the Sloan Digital Sky Survey, are gravitationally interacting. (Photo: Sloan Digital Sky Survey) 

A close look at active lava flows produced by Hawaii’s Kīlauea Volcano (Photo: USGS Hawaiian Volcano Observatory)

NASA’s Solar Dynamics Observatory (SDO) recently caught this spectacular coronal mass ejection (CME). The sun spat out a more than 804,672-km-long filament of solar material that had been hovering in the sun’s corona. The CME did not travel directly toward Earth, but did connect with Earth’s magnetic environment, or magnetosphere, with a glancing blow that left beautiful auroras in its wake. (Photo: NASA)

The world’s smallest scale, which cannot be seen with the human eye. Developed by a team led by scientists at the California Institute of Technology (Caltech), the device measures the mass of individual molecules.  It is so tiny that an electron miscroscope is needed to photograph it.  The scale bar at the bottom is two microns (millionths of a meter).  (Photo: Caltech / Scott Kelber and Michael Roukes)

Russian cosmonaut Gennady Padalka, Expedition 32 commander, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. (Photo: NASA)

A Concentrating Solar Power (CSP) system in Albuquerque, New Mexico. CSPs concentrate a large area sunlight with mirrors and lenses.  The concentrated sunlight is then converted into heat, which drives a turbine power system to produce electricity. (Photo: Randy Montoya/Sandia National Laboratory)

The famous “boot” shape of Italy is illuminated by the country’s night lights.  In this photo, taken from aboard the International Space Station, you can also see Sardinia and Corsica just above the left center of the photo. Sicily is at lower left.  (Photo: NASA)

Beluga whales at Marine Land in Canada pose for the camera. Marine mammals, such as these whales, are protected within the United States by the Marine Mammal Protection Act (MMPA) of 1972. Before they can be brought into the US or put on public display, permits, issued by the NOAA (National Oceanic and Atmospheric Administration), must be obtained. (Photo: Jennifer Skidmore/NOAA)

A composite image taken by NASA’s Chandra X-ray Observatory shows a superbubble in the Large Magellanic Cloud (LMC), The massive stars produce intense radiation, expel matter at high speeds, and race through their evolution to explode as supernovas. The winds and supernova shock waves carve out huge cavities called superbubbles in the surrounding gas. (Photo: NASA)

Droughts have taken a toll on many parts of the United States. As a result, a number of wildfires, mostly in the western US, have broken out. According to NOAA, by Aug. 8, 2012, wildfires had consumed more than 4 million acres of land. Here, firefighters continue burnout operations on the Sawmill Canyon Fire in Wyoming. (Photo: U.S. Forest Service)

The first of four towers about to be lifted as work continues on a giant wind turbine being installed at the National Renewable Energy Laboratory’s (NREL) in Colorado.  (Photo: Dennis Schroeder/National Renewable Energy Laboratory)

Of course, our Science Images of the Week would not be complete without a snapshot from Mars. Here, the Curiosity rover takes a picture of tracks it made while cruising the surface of Mars. (Photo: NASA)

Doppler radar installation in Arizona’s Empire Mountains, east of Tucson (Photo: Bill Morrow via Creative Commons/Flickr)

Curiosity takes a picture of its heat shield dropping away during its descent to the surface of Mars on Aug. 6, 2012 (Photo: NASA/JPL-Caltech/MSSS)

A technician tests a component of the Curiosity rover’s ChemCam unit, which will help identify rock and soil targets on Mars. (Photo: LeRoy Sanchez/NNSA-USDOE)

The Hubble Space Telescope captured two spiral galaxies squaring off in the constellation of Virgo. When two galaxies collide, the stars that compose them usually do not, because galaxies are mostly empty space. (Photo: NASA)

View of the interior of the newly-attached Japan Aerospace Exploration Agency’s (JAXA) transfer vehicle  docked to the International Space Station. (Photo: NASA)

Participants of marine debris removal activities sit atop a mound of derelict fishing gear collected in Hawaii. (Photo: NOAA)

This “fossil” of an electrical discharge is created by striking a nail into a highly-charged block of acrylic where this captured lightning is stored.  These creations help scientists create a network of artificial blood vessels. (Photo: Bert Hickman, Stoneridge Engineering via NSF)

Hubble’s deepest view of the universe unveils never-before-seen galaxies (Photo: NASA)

Photo taken from the submersible Alvin of a hydrothermal vent – a break in the surface of the sea floor that spews water which has been heated by the underlying magma of the Axial volcano – some 480 km west of Cannon Beach, Oregon. (Photo: Mark Spear/WHOI via NSF)

Glassy powder being applied to a metal component. When the powder is fused with lasers, it forms a new super-durable coating that helps extend the life of tools that wear out quickly. (Photo:Oak Ridge National Laboratory)

This artist’s concept shows the sky crane maneuver during the descent of NASA’s Curiosity rover to the Martian surface. (Image: NASA/JPL-Caltech)

A close-up view of a South American scarab dung beetle (Oxysternon conspicillatum) (Photo: J. Mark Rowland/Douglas J. Emlen/Courtesy: National Science Foundation)

From the Hubble Space Telescope – Star Cluster R136 bursts out (Photo: NASA, ESA, & F. Paresce (INAF-IASF), R. O’Connell (U. Virginia), & the HST WFC3 Science Oversight Committee)

Engineers checking out the Inflatable Reentry Vehicle Experiment (IRVE-3) at NASA’s Langley Research Center in Hampton, Virginia (Photo: NASA Langley/Sean Smith)

A fluorescent micrograph capturing the presence of bacteria (shown in green) on the surface of an emerging lateral root of the Arabidopsis, a small flowering plant related to cabbage and mustard (Photo: Sarah Lebeis/University of North Carolina)

As seen through a window in the Cupola, the International Space Station’s Canadarm2 grapples the unpiloted Japan Aerospace Exploration Agency (JAXA) H-II Transfer Vehicle (HTV-3). (Photo: NASA)

From NASA’s Chandra X-ray Observatory – X-rays From a young supernova remnant (Image: X-ray: NASA/CXC/STScI/K.Long et al., Optical: NASA/STScI)

A new amphibian species, the ‘Mr. Burns Beaked Toad’ (Credit: USFWS)

An aurora borealis visible in the northern sky over Merritt Reservoir in Valentine, Nebraska (Photo: Howard Edin/Courtesy: National Science Foundation)