Satellite’s Space Trip Ends After 30 Years
Artist drawing of Landsat-5 in space (Image: USGS)
The longest operating Earth-observing satellite is about to be decommissioned by the US Geological Survey.
The USGS has begun the task of lowering Landsat-5 from its operational orbit. The first series of maneuvers in that effort is likely to take place within the next month.
Landsat-5 was the fifth of seven satellites launched as part of the Landsat program, which has been acquiring satellite imagery of Earth since 1972.
Launched from California on March 1, 1984, Landsat-5 has circled Earth more than 150,000 times.
According to the USGS, which helps manage the mission, the satellite has been an extraordinary success, providing valuable contributions to the global record of land change.
Its original mission was only supposed to last three years, but Landsat-5 continued to deliver imagery and data for more than 25 more years beyond that.
The satellite experienced a number of problems over the years, but scientists and technicians managed to bring it back from the brink of failure.
This image of the abandoned city of Pripyat, home to the Chernobyl Nuclear Power Plant was taken by Landsat-5 three days after the April 26, 1986, nuclear accident. (NASA)
However, the recent failure of one of its gyroscopes proved to be one problem too many, finally bringing Landsat-5’s decades-long mission to an end.
“This is the end of an era for a remarkable satellite, and the fact that it flew for almost three decades is a testament to the NASA engineers and the USGS team who launched it and kept it flying well beyond its expected lifetime,” said Anne Castle, Department of the Interior assistant secretary for Water and Science. “The Landsat program is the gold standard of satellite observation, providing an invaluable public record of our planet that helps us tackle critical land, water, and environmental issues.”
Over more than a quarter of a century, Landsat-5 observed and sent back Earth imagery and data reflecting the many changes which have taken place on our planet, not only from natural hazards and a changing climate, but also due to land use practices.
It observed the eruption of Mount Saint Helens, the 1991 Kuwaiti oil fires set by a fleeing Iraqi military, the 1986 Chernobyl nuclear disaster, as well as rainforest depletion, wildfires, floods, global crop production, and the expansion and retreat of the Earth’s ice shelves.
Image taken by Landsat-5 in 1991 shows inky-black smoke pouring from burning oil wells which were set afire by defeated Iraqi military forces as they retreated from Kuwait. (NASA)
“Any major event since 1984 that left a mark on this Earth larger than a football field was likely recorded by Landsat-5, whether it was a hurricane, a tsunami, a wildfire, deforestation, or an oil spill,” said USGS Director Marcia McNutt. “We look forward to a long and productive continuation of the Landsat program, but it is unlikely there will ever be another satellite that matches the outstanding longevity of Landsat-5.”
Landsat-5 observations have helped increase our understanding and awareness of the impact humans have on the land, according to the USGS.
With Landsat-5 out of commission, a number of Earth-observing satellites put into space by other governments and private companies, continue to operate.
Landsat-7, which launched in 1999, and the upcoming Landsat-8 (LDCM), which launches in 2013, will take up where Landsat-5 left off, continuing to keep watch over an ever-changing planet.
Science Images of the Week
NASA’s Cassini spacecraft recently snapped this spectacular view of Saturn, taken while the spacecraft was in Saturn’s shadow. The cameras were turned toward Saturn and the Sun so that the planet and rings are backlit. (NASA)
This sabal causiarum, commonly known as the Puerto Rican hat palm, was planted in 1932 at the Montgomery Botanical Center in Coral Gables Florida. (P. Barry Tomlinson, National Tropical Botanical Garden, Miami/American Journal of Botany)
This linear accelerator produces x-ray pulses that capture images of atoms and molecules in motion and is for an astrophysics experiment at the SLAC National Accelerator Laboratory’s Linac Coherent Light Source (LCLS),. (Jose R. Crespo Lopez-Urrutia/Max Planck Institute for Nuclear Physics)
Lava flows down central Ecuador’s Tungurahua volcano in this photo taken at a slow shutter speed. (AP)
A map of the moon’s gravity field, as measured by NASA’s Gravity Recovery and Interior Laboratory (GRAIL). Areas colored in red have a high degree of local gravity, the blue blotches show lower local gravity, and other colors indicate varying degrees of local gravity in between red and blue. (NASA)
Scientists use this device, a diamond anvil cell (DAC), in experiments to recreate the pressure that exists deep inside planets. (Roy Kaltschmidt, Berkeley Lab)
This striking image of the planetary nebula NGC-5198, was taken by the Hubble Space Telescope. (NASA)
These six huge fans provide wind for the wind tunnel at NASA’s National Full-scale Aerodynamics Complex in California. (NASA)
This endangered hawksbill is one of seven species of the world’s sea turtle. Its shell is made up of overlapping plates which are thicker than those of other sea turtles. This heavy-duty shell protects them from being battered. (NOAA)
In a photo captured from the International Space Station, a mammoth plume of smoke emanates from the erupting Ulawan volcano, located on the island of New Britain, Papua New Guinea. (NASA)
Scientists Strike ‘Scientific Gold’ in California
Fragments of the Sutter’s Mill meteorite fall collected by astronomer Dr. Peter Jennisken. (NASA)
Researchers have struck scientific gold at Sutter’s Mill, site of the famed California Gold Rush where the precious metal was first discovered in 1848.
In April of this year, the scientists recovered a rare meteorite which contains clues to the early history of the solar system.
Using Doppler radar, the same technology used by weather forecasters, the scientists detected a shower of meteors raining down over the communities of Coloma and Lotus, just after the asteroid broke up in the atmosphere.
That allowed scientists to, for the first time, quickly find, recover and study a primitive meteorite that had little exposure to the elements.
It’s the most pristine look at the surface of ancient asteroids scientists have been able to study so far. Because of the rapid recovery of materials, scientists were able to detect compounds that quickly disappear once a meteorite hits Earth.
Reporting in Science, the researchers say their rare find was classified as a Carbonaceous-Mighei or CM-type carbonaceous chondrite meteorite, which is known to contain water and complex organic compounds, such as amino acids, molecules that help form life.
But, according to NASA’s Danny Glavin, he and the other scientists weren’t able to detect many of the amino acids in their find because it appeared the samples had been heated in space before arriving on Earth.
“The small three meter-sized asteroid that impacted over California’s Sierra Nevada came in at twice the speed of typical meteorite falls,” said lead author Peter Jenniskens, of the SETI Institute and NASA’s Ames Research Center, both located in California. “Clocked at 64,000 miles per hour, it was the biggest impact over land since the impact of the four meter-sized asteroid 2008 TC3, four years ago over Sudan.”
The scientists also say that, for the first time, they were able to identify the region of space where these types of meteorites come from.
After studying photographs and video of the asteroid, Jenniskens figured that it came in on an unusually low-angled orbit, more like a comet‘s orbit, passing closer to the sun than what has been learned from past recorded meteorite falls.
Scientists found the asteroid, as it was in orbit, was influenced by the gravity of both the Sun and Jupiter at times.
“It circled the sun three times during a single orbit of Jupiter, in resonance with that planet,” Jenniskens said.
A meteor flashes across the sky during the peak of the November 2009 Leonid Meteor Shower. (Photo: Ed Sweeney via Wikimedia Commons)
The asteroid that spawned the meteorite was estimated to be around 45359 kg. Of that, less than 1kg was actually recovered on the ground in the form of 77 tiny meteorites. The biggest of those meteorites was 205 grams.
While the scientists didn’t find much actual gold in the Sutter’s Mill meteorite, about 150 parts per billion, it was still “scientific gold,” according to co-author and cosmochemist Qing-zhu Yin of the University of California at Davis.
“With 78 other elements measured, Sutter’s Mill provides one of the most complete records of elemental compositions documented for such primitive meteorites,” he said.
Study: Human Hand Evolved So Fist Could Club Enemies
A clenched human fist (Photo: Ralpharama via Wikimedia Commons)
The human hand is a sophisticated work of art and science. Refined through centuries of evolution, hands enable us to perform unique functions which help us to not only survive but also to thrive as a species.
New research suggests the evolution of the modern human hand may be due to a very basic need: for use as a weapon.
In a study published in The Journal of Experimental Biology, University of Utah scientists theorize human hands evolved their unique square palms and long thumb in order to stabilize the fist, providing a built-in compact club early humans could use in combat.
An impassioned conversation with a colleague inspired David Carrier to pursue research on the matter.
In the course of their conversation, Frank Fish, an expert in biomechanics, formed a fist and said, “I can hit you in the face with this, but that is not what it evolved for.”
Fish’s proclamation made Carrier stop and think. While the human hand evolved to allow great dexterity, according to Carrier, a chimpanzee can also manipulate its hands in a way that would give it greater manual dexterity, but they still may not necessarily be able to form their hands like humans do.
Modern chimpanzees, according to Carrier, have long palms and fingers with a short thumb, while the human palm and fingers are much shorter and the thumb longer and stronger.
Three views of a clenched human fist show how we buttress the fist to reduce the chance of hand injury when punching. (Photo: Denise Morgan for the University of Utah)
This difference brought on by evolution, allows us to clench our hand into a fist whenever we fold our thumb across the fingertips. A chimpanzee’s fingers, on the other hand, forms the shape of what he describes as an open doughnut shape when curled.
Carrier said that he wondered if the tightly-packed human fist provides some internal support to our fingers in order to protect them from being damaged during an altercation and if it also provides humans with the ability to deliver a more powerful blow against their opponents, as compared to the slap of an open hand.
Carrier and Morgan decided to find out whether hands are more effective when balled into a fist or used as an open-handed slap.
“Fortunately, Michael had a lot of experience with martial arts and he knew people who were willing to serve as subjects,” said Carrier.
First, the test subjects were asked to smack a punching bag with their hands formed into a wide variety shapes; from the open-handed slap to the tightly-clenched fist, using various styles to deliver the blows, such as over the arm, sideways and head on. As each of the fighters walloped their punching bag foe, the researchers would measure the force of each impact.
But after looking at the results of that experiment, the researchers were surprised to see the punch did not deliver more force per blow.
“In terms of the peak forces or the impulse, it did not matter whether the subjects were hitting with a clenched fist or open palm,” said Carrier.
Fists formed only by a human hand can be used as a weapon without causing injury to the person delivering the punch. (Photo: Courtney “Coco” Mault/Wikipedia Commons via Flickr)
Morgan and Carrier then wanted to find out whether supporting the hand, by curling the fingers and thumb, stiffens the structure of the hand. Asking their test subjects to form their hands into various fist shapes, the researchers measured the rigidity of the first knuckle joint of their subject’s index finger, first with the support of the thumb over the finger and then without the support of the thumb. They found the knuckle joint was four times more rigid when supported by the thumb.
Next, the researchers measured the amount of force that the fighters could deliver through the fist surface of their index and middle fingers. Again, they found that by using the thumb in forming a fist, the test subjects doubled the delivered force by transmitting it to the wrist through the palm bones of the thumb and the index finger.
The results of their experiments led Carrier and Morgan to conclude the square-shaped palms of today’s humans are perfectly proportioned to stiffen into a fist to be used as a weapon that delivers powerful punches without injuring ourselves.
Health Concerns Could Ground Citizen Astronauts
In April 2002, South African computer entrepreneur Mark Shuttleworth paid about $20 million for a round-trip flight to the International Space Station aboard a Russian Soyuz spacecraft. Shuttleworth underwent a year of training and preparation before the space flight. (NASA)
A group of former NASA executives plans to offer excursions to the moon to anyone who can afford the $1.4-million-dollar-per-couple ticket price.
Golden Spike Co. is the latest private company to join the burgeoning space tourism industry.
Once operations launch, the public demand for seats on commercial spacecraft is expected to grow from 373 seats in the first year, to 533 seats in the 10th year, for a ten-year total of 4,518 seats, according to the US Federal Aviation Administration.
Aside from money, health might be a factor in deciding whether or not to take a space vacation. Professional astronauts go through rigorous testing and conditioning before jetting into space.
A study in the British Medical Journal suggests the medical community should establish a set of health screening standards for potential space tourists to determine whether they can withstand the rigors of space travel.
At the moment, there is no standard outlining how medical professionals should advise patients about the health implications of space travel.
NASA’s selection process for picking the first American astronauts included extensive physical and psychological testing. Here, Mercury astronaut Walter Schirra’s lung capacity is tested. (NASA)
“We all have questions from patients related to air travel,” said the study’s lead author Dr. S. Marlene Grenon from the University of California, San Francisco. “In the short future, we may be getting questions from our patients about space travel.”
Medical doctors and other scientists have researched the impact of space travel on the human body ever since the space race between the USA and the former USSR began in 1957. A half-century later, scientists have found space travel does profoundly affect humans, both physically and mentally.
“In a zero-gravity outer-space environment, humans go through very unique physiological changes,” said Grenon. “They experience bone loss, muscle atrophy, increased risk of certain heart problems, a decrease in immune function, kidney stones and motion sickness. These significant changes in the body and how it functions need to be considered.”
Space health guidelines could also help doctors treat those who might suffer the ill effects of space travel while in flight.
So far, commercial space tourism has served only a few passengers and they’ve all gone through the rigorous screening and training given to professional astronauts.
“The changes that occur in zero gravity happen for several reasons,” Grenon said. “This includes volume redistribution towards the chest and head, decrease use of the lower extremities, and the lack of gravitational stimuli on the cells.”
Virgin Galactic has scheduled its first space tourism flight, which will ferry citizen astronauts who pay $200,000 per ticket. (Virgin Galactic)
The study’s senior author Millie Hughes-Fulford, also from UCSF, knows a bit about the impact of space flight on the human body. She was the first woman to travel into space as a working scientist on board the shuttle Columbia in 1991.
“It feels like you’re on top of a roller coaster while you’re in outer space. That feeling, in the pit of your stomach, is what you’ll experience the entire time,” said Hughes-Fulford. “You must check with your doctor to see if your heart and other vital organs are up for this type of adventure.”
Grenon said a new field of medicine could open up as a result of the expected rapid growth of the space tourism industry.
“In the future, I think we can expect space medicine doctors will be needed specifically for the commercial space sector as demand increases,” she said. “And these experts would likely link with specialists on Earth in different fields such as cardiology, vascular surgery or neurology when it comes to specific questions on a condition in space or recommendations on how to best manage a medical problem prior to a flight.”
New Species of World’s Only Venomous Primate Found
One of the newly identified species of slow loris, Nycticebus kayan. (Photo: Ch’ien C Lee)
An endangered lemur-like primate with two tongues and a toxic bite has more branches on its family tree than originally thought.
Writing in the American Journal of Primatology, Missouri researchers say they’ve identified three new species of the slow loris – the only venomous primate in the world – living on the Indonesian island of Borneo.
At first glance, with its big brown eyes and teddy-bear face, this nocturnal mammal appears cute and cuddly, but it’s got a lethal bite, which can cause fever, pain and swelling. For humans who suffer from allergic reactions, it can also be deadly.
Due to a benign appearance, and its uses in traditional medicine, the slow loris is a favorite of poachers throughout southeastern Asia and its surrounding islands.
The three newly identified species were originally grouped with another species. Now that the slow loris has been divided into four distinct classes, its risk of extinction is greater than previously believed. However, in the long run, it could also help efforts to protect the primate.
“Four separate species are harder to protect than one, since each species needs to maintain its population numbers and have sufficient forest habitat,” says lead author Rachel Munds from University of Missouri. “Unfortunately, in addition to habitat loss to deforestation, there is a booming black market demand for the animals. They are sold as pets, used as props for tourist photos or dismembered for use in traditional Asian medicines.”
The teeth of a juvenile slow loris are removed by an animal trafficker. (Photo: International Animal Rescue)
Munds says slow lorises are not and cannot be domesticated and that keeping them as pets is cruel. The primates are protected under the Convention on International Trade in Endangered Species.
“Zoos rarely succeed in breeding them,” says Munds. “Nearly all the primates in the pet trade are taken from the wild, breaking the bonds of the lorises’ complex and poorly understood social structures.”
Those who breed them as pets often pull out the teeth, depriving the the animal of its venomous bite. Many of these illegally captured primates die due to the foul conditions of pet markets.
“Once in the home, pet keepers don’t provide the primates with the social, nutritional and habitat requirements they need to live comfortably,” Munds says. “Pet keepers also want to play with the nocturnal animals during the day, disrupting their sleep patterns.”
The under-tongue of a slow loris sticks out beneath the primary tongue. (Photo: David Haring – Duke Lemur Center)
The Missouri researchers examined various museum specimens, photographs and actual live animals that had been lumped into the original single species. After noticing the animals had different body sizes, fur thickness, habitats and facial markings, scientists realized they’d identified four separate species of the slow loris rather than just the one.
Now instead of one animal listed as vulnerable by the International Union for the Conservation of Nature, there may be four endangered or threatened species.
Mystery Properties of Black Holes Revealed
An artist’s drawing shows a large black hole pulling gas away from a nearby star. (NASA)
Of all the celestial objects that make up the Universe, nothing is more mysterious than the black hole.
Now Denmark scientists have come up with what they say are groundbreaking theories that explain several properties of the enigmatic black hole. The scientists’ research indicates black holes have properties similar to the dynamics of both solids and liquids.
Albert Einstein- circa 1921 (Photo: Creative Commons/Wikipedia)
What’s generally known about black holes is that they’re extremely compact –some are as small as less than .01 mm– and that they can generate a gravitational pull so powerful that anything and everything that comes near them is swallowed up, including light.
We’re not able to see these cosmic vacuum cleaners because any light that does hit them is absorbed rather than being reflected. Black holes were predicted by Einstein’s general theory of relativity but scientists haven’t been able to determine their properties.
“Black holes are not completely black, because we know that they emit radiation and there are indications that the radiation is thermal, i.e. it has a temperature,” explains Niels Obers, a professor at the University of Copenhagen.
Obers says one can view black holes like particles. Since, in principle, a particle has no dimensions, it is merely a point. But, if a particle is given an extra dimension –such as a straight line– it then becomes a string. And if you give the string yet an additional dimension, it becomes a plane. Physicists refer to one of these planes as a ‘brane’, similar to the biological term, ‘membrane’.
“In string theory, you can have different branes, including planes that behave like black holes, which we call black branes,” Obers says. “The black branes are thermal, that is to say, they have a temperature and are dynamical objects. When black branes are folded into multiple dimensions, they form a ‘blackfold’.”
Artist impression of black branes forming a “blackfold”(Artist impression by Merete Rasmussen)
Obers and his colleagues say they’ve been able to develop their new theories on the physics of black holes based on the principals of these black branes and blackfolds.
“The black branes are hydro-dynamic objects, that is to say that they have the properties of a liquid,” says Jay Armas, who also worked on the project. “We have now discovered that black branes also have properties which can be explained in terms of solids. They can behave like elastic material when we bend them.”
“With these new theories, we expect to be able to explain other black hole phenomena, and we expect to be able to better understand the physical properties of neutron stars,” said Obers.
Scientist Discover Way to Lose Weight Without Dieting
British scientists have found you can lose weight without dieting – by replacing high-fat foods with their low-fat counterparts.
Writing in the British Medical Journal, researchers from the University of East Anglia found that people who switched out high-fat foods with low-fat substitutes lost about 1.6 kg over six months without any additional dieting.
They also found lowering fat in your diet provides additional health advantages, such as lowering blood pressure and bad cholesterol levels.
The researchers believe their findings could play a role in dietary recommendations to help in the worldwide battle against obesity. The WHO and other public health organizations say obesity is a major risk factor for high blood pressure, cardiovascular disease, diabetes, some cancers and musculoskeletal disorders, such as the highly disabling degenerative disease of the joints, osteoarthritis.
A display of high fat foods such as cheeses, chocolates, lunch meat, french fries, pastries, doughnuts, etc. (Photo: US National Cancer Institute)
Looking to update its guidelines on total fat intake, the WHO recently commissioned a study to evaluate the relationship between the amount of fat and fatty products consumed in daily diets and various indicators of body fatness such as total weight, waist size and/or body mass index (BMI).
For their study, the researchers evaluated 33 trials in North America, Europe and New Zealand, involving 73,589 participants of various ages and states of health.
Researchers compared the waistline measurements and weight of participants who ate a reduced-fat diet with those whose diet included the usual amounts of fat for at least six months.
Along with the loss of 1.6 kg of bodyweight, they also found that the participants reduced their total BMI by 0.56kg/m² – kg per square meter -and cut their waist circumference by 0.5cm.
Nutritionists recommend foods with protein (eggs/lean meat), whole grains, and fruits (or vegetables) for a healthy breakfast (Photo: Kenji Ross via Flickr/Creative Commons)
Wondering if the weight reduction by those in the group that consumed few fats was due in part to the additional time, attention and support they received, compared to those in the normal fat intake group, researchers looked to studies where both groups were given equal time and attention and found that the weight reduction did not disappear suggesting that the weight loss was really due to lower fat intake.
“The effect isn’t dramatic, like going on a diet. The research specifically looked at people who were cutting down on fat, but didn’t aim to lose weight, so they were continuing to consume a normal amount of food,” said Dr. Lee Hooper, who led the research. “What surprised us was that they did lose weight, their BMI decreased and their waists became slimmer. On top of this, they kept their weight down over at least seven years. There isn’t a specific goal, the more fat you cut down, the more your weight falls.”
Speeding Space Junk Poses Risks for Spacecraft
The amount of space junk floating around the Earth grows every year, and increasingly can pose risks to spacecraft orbiting the planet.
This computer generated graphic provided by NASA shows objects in Earth orbit that are currently being tracked. Space junk has made such a mess of Earth’s orbit that experts say we may need to finally think about cleaning it up. (AP)
In the United States, NASA’s Orbital Debris Program (ODP) at the Johnson Space Center in Texas, keeps an eye on the ever-expanding junkyard of space.
“We define orbital debris as any man-made object orbiting the Earth that is no longer serving a useful purpose,” says Gene Stansbery, project manager for the ODP. “That can be anything from very large rocket bodies and dead satellites that are no longer useful, all the way to very tiny particles that are eroded from the painted surfaces of spacecraft or rockets, the entire size range.”
In the weightless and friction-free environment of orbit, it’s not so much the size of all this junk floating in the Earth’s orbit, but also the speeds at which it travels, according to Stansbery.
“If you look at orbital velocities and the average collision velocity, you’re talking on the order of 11 kilometers a second,” he says. “So even a small paint fleck can damage a sensitive component for spacecraft.”
An example occurred during STS 7, when a window for the space shuttle had to be replaced for the first ever time after being damaged by a .2 millimeter paint fleck. If that level of damage can be caused by a particle that small, one can imagine the threat posed by larger orbiting refuse.
Given that space exploration has been an on-going venture since the 1950s, there’s a lot of old stuff circling the planet, and much of it can pose serious risks.
“The Department of Defense has a world-wide network that can track objects down to about 10 centimeters in size in low Earth orbit,” says Stansbery. “For those objects, there’s about 22,000 that they’re tracking. You go down to about one centimeter and larger, you’re talking about 500,000, and if you get smaller than that and you’re talking into the millions.”
Some of that stuff, especially in low-Earth orbit, will eventually fall back to the planet, much of it burning up on re-entry. However, for junk found at higher altitudes, around 1,000 kilometers or so, Stansbery says it could remain in orbit for decades, maybe even hundreds of years. For altitudes even higher than that, junk could remain for centuries…or longer.
A white arrow points to damage on a piece of a solar array from the Russian space station Mir. The array had been damaged by a miniscule piece of space junk. (AP)
Major collisions are rare, but they do happen. On Feb. 10, 2009, two large satellites, the Iridium 33 and the Kosmos 2251, collided at a speed of about 42,000 kilometers per hour. The collision spread about 1,000 pieces of debris capable of being tracked across the skies, where much of it remains.
In March of this year, one of those pieces came uncomfortably close to the International Space Station. So close, in fact, that as a precaution, the ISS’ six-member crew waited for a time in the Soyuz emergency exit capsule, just in case a collision occurred and they had to abandon ship.
More worrisome, says Stansbery, is that the crew only had 24 hours notice of the possible collision. “Unfortunately, that is too short a time to plan a re-avoidance maneuver for the space station,” he says.
The threat posed by space junk isn’t new; space scientists have been concerned about it since the 1970s. However, with more rockets taking off, more satellites in the sky, and more spacecraft – such as from China or private firms like SpaceX and Blue Origin – the skies are getting more crowded all the time.
This week on VOA’s “Science World” radio program, you can hear the complete interview with Gene Stansbury on space junk, as well as other features on the science behind children’s snack food choices, the lingering effects of the Gulf of Mexico oil spill on corral communities, and a new web-based computer program that helps doctors save lives. Take a look at the right hand column for scheduled times.
(Written by Doug Bernard, Digital Frontiers Editor)
Science Images of the Week
This NASA image shows the work site of the Curiosity rover on Mars. The first test of Martian soil by Curiosity shows no definitive evidence that the red planet has the chemical ingredients to support life. (NASA)
NASA’s artist rendering of Voyager 1 at the edge of the solar system. The long-running spacecraft has entered the fringes of the solar system which is thought to be the last layer before the beginning of interstellar space, or the space between stars. Mission chief scientist Ed Stone says Voyager 1 will be the first manmade object to leave the solar system. (AP Photo/NASA)
A 68-mile-diameter crater, large indentation at center, in the north polar region of Mercury which has been shown to harbor water ice, thanks to measurements by the Messenger spacecraft. (AP Photo/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)
Joe Wasilewski works with a captured Nile crocodile, caught near his Homestead, Fla., home. State wildlife officials have given their agents a rare order to shoot to kill in the hunt for a young and potentially dangerous Nile crocodile loose near Miami. “They get big. They’re vicious. The animals are just more aggressive and they learn that humans are easy targets,” says Wasilewski, a reptile expert and veteran wrangler. (AP)
The Plosky Tolbachnik volcano erupts in Russia’s Far Eastern Kamchatka Peninsula. The volcano, located on the peninsula’s eastern coast, is erupting for the first time in 36 years. (AP)
In an undated photo, Glenn Storrs, left, helps haul a dinosaur fossil on a contraption made from two hospital gurneys and a motorcycle wheel, dubbed the dino wheel, near Pryor Mountains in Montana. After 10 years of painstakingly unearthing scattered dinosaur fossils at a site along the base of the Pryor Mountains, Storrs believes he has finally figured out how the bones arrived at their final resting place 145 million to 150 million years ago. His theory is that a group of young dinosaurs, probably migrating with adults, died of thirst while searching for a wetter environment.
(AP Photo/Courtesy of Cincinnati Museum Center via The Billings Gazette)
A shadow self-portrait taken by NASA’s Opportunity rover on the Martian surface. The solar-powered spacecraft has been exploring a huge crater in the Martian southern hemisphere and has detected what appear to be clay minerals. (AP Photo NASA)
Multiple dust plumes are seen blowing off the coasts of Iran and Pakistan in this NASA handout image taken Nov. 29, 2012. These images document the movement of the plumes southward over the Arabian Sea. (REUTER/NASA/Jeff Schmaltz)
The moon Tethys (in the upper left of the image) is seen next to Saturn in this NASA image taken from the Cassini spacecraft on Aug. 19, 2012 and released Dec. 3, 2012. Saturn’s rings appear to dwarf Tethys (660 miles, or 1,062 kilometers across) although scientists believe the moon to be many times more massive than the entire ring system combined. The view was acquired at a distance of approximately 1.5 million miles (2.4 million kilometers) from Saturn. (REUTERS/NASA)
- n this photo made Thursday, Nov. 29, 2012, The Plosky Tolbachnik volcano erupts in Russia on Thursday, Nov. 29, 2012, for the first time in 36 years. (AP)