A ruined street in the Haitian capital of Port-au-Prince appeared much the same on September 30, 2010, (bottom) as it did seven months earlier—shortly after the devastatingHaiti earthquakeon January 12, 2010, which the local government estimates killed more than 220,000 people.
The magnitude 7.0 temblor destroyed more than 97,000 homes and damaged more than 188,000 structures, displacing 1.3 million people.
(See relatedpictures taken the day after the Haiti earthquake.)
—Brian Handwerk
An entiregalaxymay be lurking, unseen, just outside our own, scientists announced Thursday.
The invisibility of"Galaxy X"—as the purported body has been dubbed—may be due less to its apparent status as a dwarf galaxy than to its murky location and its overwhelming amount of dark matter, astronomerSukanya Chakrabartispeculates.
Detectable only by the effects of its gravitational pull, dark matter is an invisible material that scientists think makes up more than 80 percent of the mass in the universe. (See"Dark Matter Detected for First Time.")
Chakrabarti, of the University of California, Berkeley, devised a technique similar to that used 160 years ago to predict the existence of Neptune, which was given away by the wobbles its gravity induced in Uranus's orbit.
Based on gravitational perturbations of gases on the fringes of our Milky Way galaxy, Chakrabarti came to her conclusion that there's a heretofore unknown dwarf galaxy about 260,000 light-years away. (Related:"Huge Black Hole Found in Dwarf Galaxy.")
With an estimated mass equal to only one percent the mass of the Milky Way, Galaxy X is still the third largest of the Milky Way's satellite galaxies, Chakrabarti predicts. The two Magellanic are each about ten times larger.
If it exists, Galaxy X isn't likely to be composed entirely of dark matter.
It should also have a sprinkling of dim stars, Chakrabarti said."These should provide enough light for astronomers to see it, now that they know where to look,"she said.
The reason the dark matter galaxy hasn't yet been seen, she added, is because it lies in the same plane as the Milky Way disc. Clouds of gas and dust stand between us and Galaxy X, confounding telescopes.
(See"'Lost' Dark Matter Discovered in Space.")
Galaxy X Addresses Fundamental Problem
If Galaxy X's existence is confirmed, it would be a major step in verifying our understanding of how the universe condensed from primordial matter and energy after thebig bang, Chakrabarti said.
Current theory correctly predicts the distribution of distant galaxies, she said. But it also predicts hundreds of dwarf galaxies around the Milky Way, and to date only a few dozen have been found.
This"missing satellite problem"she said,"is a fundamental problem in cosmology."
More Dark Galaxies Out There?
Galaxy X could soon lead to Galaxies Y and Z, according to Chakrabarti.
"This is basically a new method to render dark galaxies visible,"she said, adding that her technique should be able to detect dim dwarf galaxies as small as a thousandth the mass of the Milky Way.
The new finding is a useful contribution to projects aiming to map the distribution of dark matter on the far edges of the universe, according to David Pooley, a Texas-based dark matter astronomer withEureka Scientific, a private corporation that helps scientists secure research funding.
"All of these dark matter studies are really starting to map out the distribution of dark matter,"said Pooley, who was not part of Chakrabarti's team."Any information we get is extremely valuable."
(Related:"Dark Matter Helped Early Galaxies Survive 'Massacre.'")
Galaxy X: The Search Begins
Now that astronomers know where to look for Galaxy X, they should be able to find it, especially if they conduct the search in dust-penetrating infrared light, Chakrabarti said.
"Say you're looking for a car with very dim headlights, in the fog,"she said."If you know approximately where to look, you would have a better chance of finding it."
Chakrabarti hopes to do some looking herself within the next few months and is seeking to secure time at a large infrared telescope.
Even if Galaxy X isn't confirmed, she said, her findings will still shed new light on a shady subject.
The absence of X would mean there's some other oddity out there throwing off the calculations—perhaps an unexpected distribution pattern of the halo of dark matter thought to surround the Milky Way.
"We still stand to learn something very fundamental,"she said.
The Galaxy X study is pending in theAstrophysical Journal.
This story is part of aNational Geographic News serieson global water issues.
From the passenger seat of a truck rumbling along a rough and dusty road in rural Haiti, Drew Kutschenreuter points out trees planted to feed the country’s charcoal habit, patches of millet, and irrigation canals cut along the sides of rolling brown hills.
An agronomist from Wisconsin, Kutschenreuter has been working in Haiti for more than two decades, most recently on soil conservation and hillside terracing projects run by the International Organization for Migration. Kutschenreuter’s goals: to create jobs and reverse the country’s downward spiral into ecological degradation and extreme poverty—problems exacerbated by last year’s earthquake and the island’s history of hurricane damage.
(Related:“Haiti Earthquake Anniversary: Pictures Show Slow Recovery.”)
With only a fraction of its forest cover remaining, Haiti has become increasingly vulnerable to flash floods and mudslides. Without underground tree roots, only a quarter of the water that should permeates the soil. Storms often damage what water systems do exist, crippling access to clean drinking water supplies. The United Nations (UN) estimates some 36 million tons of rich topsoil are carried away each year by wind and rain, much ending up in rivers and lakes that become lifeless mudscapes during the rainy season. With the loss of soil fertility, crop yields drop, and farmers have increasingly turned to cutting trees for firewood and charcoal as a source of revenue.
With the recent outbreak of cholera in camps crowded with earthquake victims, and in mountainous rural areas where people take their drinking water from the river or underground wells, there may be an added stress on forest resources. According to Wesler Lambert of Partners in Health, when citizens are asked to boil water as a protection measure against cholera or other water-borne diseases, they use charcoal, leading to more deforestation and therefore more flooding.
(Read more in William Wheeler’s blog post: “Haiti’s Cycle of Calamity.”)
Rebuilding Hillsides, Futures
Kutschenreuter works in an area of northern Haiti called Gonaîves, which did not see earthquake devastation, overseeing planting and hillside terracing projects to slow down the flow of water and protect topsoil. While the project area is only a small patch of Haiti, it offers a glimpse of how an environmentally rehabilitated landscape could look.
Mending Haiti’s environment is the ambitious end game of a new program called the Haiti Regeneration Initiative, spearheaded by Columbia University’s Earth Institute and the UN Environmental Programme (UNEP). The effort started in 2008 with the ecological restoration of one of the country’s several dozen watersheds. Now, having secured $8 million in funding, the project’s leaders are expanding its scope along Haiti’s southern coast, and will couple environmental restoration with development efforts, such as building infrastructure for drinking water and sanitation, and efforts to improve the livelihoods of local Haitians.
Until now, much of the work has been focused on planning: using soil quality surveys, and satellite data that accounts for topography and water patterns, to create a map that determines which hillsides can support which crops. They’ve also installed an automated rain gauge, which communicates wind speed and precipitation data in real-time via satellite back to New York, and could be developed into a flood risk early warning system.
The program builds on practices the UN has developed in African villages."Haiti's are among the lowest crop yields in the world,” said Marc Levy, a Columbia University professor and Earth Institute program director. “By using fertilizer feeds and best management practices, they could double or triple their yields very quickly.” Fruit-bearing trees like banana and mango could be planted along hillsides, and walls builtto shore them up against erosion. By focusing on more efficient use of “good” land, like plateaus, farmers might be able abandon some of the steeper grades altogether. Reforestation programs could provide alternative jobs to cutting trees for firewood and charcoal production.
But the idea that choosing not to farm a particular slope because of its value for flood protection and water quality—an individual sacrifice for a collective benefit—challenges the coping strategies that poor farmers have relied on for centuries, said Levy. He argues that it will take a significant change, like the one the Haiti Regeneration Initiative promotes, to reverse the country’s ecological decline.
Many scientists and policymakers have long recognized the consequences of charcoal dependency. A better strategy for Haitian farmers, according to a 2008 economist's report commissioned by UN Secretary-General Ban Ki-moon, would be to plant high-value mango trees for export. A tree-cutting tax could be established to subsidize alternative jobs for charcoal producers—as tree-planters and park rangers. But poor farmers, who have been largely cut out of export profits, traditionally choose subsistence farming. Changing the incentives would require strong government leadership—and a lack of such leadership was an obstacle to the larger reconstruction effort even before elections in late November were marred by fraud and touched off unrest, according to analysts.
Without a strong government committed to addressing these problems in Haiti, environmental rehabilitation programs have had, at best, mixed results. Common failures among such projects, which have received a total of $391 million since 1990, according to the Haiti Regeneration Initiative, include a lack of coordination among international aid organizations and government ministries, a failure to provide alternative jobs and secure local participation, and a history of"short-term interventions applied to long-term issues."
Kutschenreuter’s project in Gonaîves was the first to incorporate advice from the UN Environmental Programme in its approach, according to UNEP’s Antonio Perera.
A major tenet of the Haiti Regeneration Initiative is the importance of cooperation between NGOs, the government, and the residents in project areas. Much of the work in the next year will build on partnerships with a committee of local leaders, according to Earth Institute’s Alex Fisher.
“We’re seeing the initial stages of a coalition of groups that together have the potential to reach a significant proportion of the population and have very strong relationships with all the major players,” Fisher said. “If we keep following this track, there’s definitely reason to be hopeful.”
William Wheeler’s ongoing reporting in Haiti is supported by a grant from thePulitzer Center on Crisis Reporting.
Could this partly gilded hilt have held Blackbeard's sword? There's no way to know for sure, though it was found amid theNorth Carolinawreck of theQueen Anne's Revenge, the flagship of the infamous 18th-century pirate.
Since 1997, archaeologists have been excavating theQueen Anne's Revenge. The sword hilt—found in pieces but reassembled for this picture—is among their latest finds and was revealed to the public this month.
(Related: exclusivepictures of Blackbeard pirate relics and gold.)
After running aground on a sandbar in 1718 near the town ofBeaufort (map), the ship was abandoned but likely remained intact and partly above water for as long as a year before collapsing and disintegrating, according to archaeologist David Moore of theNorth Carolina Department of Cultural Resources.
"In any event,"he said,"the pirates would have had ample opportunity to take anything that they thought valuable."The newfound hilt may have been left behind because it was unwanted, or it may have been inaccessible, according to Moore's colleague Wendy Welsh, a conservator on the project.
Blackbeard’s brief career as a pirate lasted only about two years, but during that time he became one of history's most feared outlaws. Operating in theWest Indies (map)and off the coast of colonial America, he struck terror into the hearts of commercial ships' captains and once held the entire city ofCharleston, South Carolina (map), hostage.
—Willie Drye
Thunderstorms can shoot beams of antimatter into space—and the beams are so intense they can be spotted by spacecraft thousands of miles away, scientists have announced.
Most so-called normal matter is made of subatomic particles such as electrons and protons. Antimatter, on the other hand, is made of particles that have the same masses and spins as their counterparts but with opposite charges and magnetic properties.
Recently, radiation detectors onNASA's Fermi Gamma-ray Space Telescopelighted up for about 30 milliseconds with the distinctive signature of positrons, the antimatter counterparts of electrons.
Scientists were able to trace the concentrated burst of radiation to alightningflash overNamibia, at least 3,000 miles (5,000 kilometers) away from the Earth-orbiting telescope, which was passing above Egypt at the time. (See anAfrica map.)
"This is a fundamental new discovery about how our planet works,"saidSteven Cummer, a lightning researcher from Duke University who was not part of the study team.
"The idea that any planet has thunderstorms that can create antimatter and launch it into space is something out of science fiction. The fact that our own planet is doing it is truly amazing."
Intense Antimatter Beam a Shocker
Scientists already knew thatthunderstorms can emit gamma rays—the most energetic form of light—and that gamma rays in turn can create positrons through a process called pair formation.
When a gamma ray with the right amount of energy interacts with an air atom, energy from the gamma ray is converted into matter, one electron and one positron, lightning expertJoseph Dwyersaid yesterday during a meeting of theAmerican Astronomical Societyin Seattle, Washington.
(Related:"Lightning Creates Particle Accelerators Above Earth.")
Scientists wouldn't have been surprised to see a few positrons accompanying any intense gamma ray burst, added Dwyer, of the Florida Institute of Technology in Melbourne.
But the lightning flash detected by Fermi appeared to have produced about 100 trillion positrons:"That's a lot,"he said.
What seems to have happened is that positrons created by the lightning were herded into a tight beam by Earth's magnetic field, said study leaderMichael Briggsof the University of Alabama, Huntsville.
The beam funneled positrons from the Namibian storm to the Fermi spacecraft.
A few milliseconds after hitting the spacecraft, the beam struck a more northerly section of Earth's magnetic field, Briggs added. This caused some of the positrons to bounce back the way they had come, hitting the spacecraft with a second beam, like an echo.
Antimatter a Clue to Lightning
Earth is constantly being bombarded by radiation from the sun, as well as cosmic rays from distant but violent events, such as powerful supernovae. (Also see"Black Holes Belch Universe's Most Energetic Particles.")
Considering the amount of positrons in the beam Fermi detected, the thunderstorm was briefly creating more radiation—in the form of positrons and gamma rays—than what hits Earth's atmosphere from all other cosmic sources combined, Dwyer noted.
The researcher has previously said, however, that thedanger of thunderstorm radiation to airline travelers is extremely low.
Duke's Cummer added that nobody knows why some thunderstorms produce gamma rays while most do not.
"We really don't understand a lot of the details about how lighting works,"he said. But discovering the creation of positrons"gives us a very, very important clue as to what's happening."
A paper about the discovery of antimatter in thunderstorms has been accepted for publication in the journalGeophysical Research Letters.
Can a single picture sum up all of 2010? In a way, yes. The above multiple-exposure photo shows the figure-eight path of thesunover the course of the entire year, known as an analemma.
Analemma photographs are made by taking a picture of the sun from the same place at the same time of day once or twice a week, generating 30 to 50 frames. This picture, made in Veszprem,Hungary, combines 36 photos of the sun taken at 10 a.m. local time between January and December. A separate picture of the neighborhood taken from the same location but at a different time of day was digitally composited into the foreground.
The sun makes this shape over a year because Earth rotates on a slightly different axis than the sun, and our planet also travels on an elliptical orbit. As one hemisphere of Earth tilts farther from the sun, the arc of the sun's daily path seen from that location lowers toward the horizon. The sun's arc then gets higher in the sky as the tilt reverses. The sun's highest point in the sky, seen in this analemma, occurs during the summer solstice, while its lowest point is during winter solstice. (Find out about alunar eclipse that happened on the 2010 winter solstice.)
Because of the time and precision involved, photographs of analemmas can be very difficult to produce. So far, only about 20 people worldwide have released successful analemma photos, according to Babak Tafreshi, founder of the astrophotography websiteThe World at Night (TWAN).
—Victoria Jaggard
Read it, but try not to weep, ladies—your tears may lower your man's sex drive, according to a new study.
Crying linked to emotions—perhaps a uniquely human behavior—is poorly understood by scientists.
However, previous research has shown that in mice, tears communicate information through"chemosignals,"causing scientists to speculate that human tears could serve a similar function.
(See"Mouse Tears Are Aphrodisiacs.")
Such chemical communication would not be a surprise, since humans are already"supremely good"at expressing themselves verbally and via body language, according to study co-author Noam Sobel, a neurobiologist at theWeizmann Institute of Sciencein Israel.
Though it's too early to know exactly what human tears are saying, one interpretation may be that a woman's emotional tears lower males' testosterone levels, thereby reducing aggression—and by default, sexual arousal.
"Put in the bluntest of ways, we've identified the chemical word for 'no,'"Sobel said.
Cry Me a River—Of Research
In multiple experiments, male subjects smelled either women's fresh tears—collected after the women had seen a sad movie—or a control liquid of saline, which was trickled down the faces of the same women.
The scientists first determined that neither liquid has a discernible odor to men.
When the men were shown photographs of ordinary women not involved in the experiment, those who had sniffed real tears were less sexually aroused than men who had sniffed saline—as revealed by the men's heart rates, skin temperatures, and testosterone levels, among other cues. (Explore aninteractive human body.)
Men who had sniffed women's tears alsosaidthey felt less turned on by the pictures than men who had sniffed saline, although the reported effect was more modest than that seen in the objective tests.
A final experiment using magnetic resonance imaging (MRI) of the men's brains backed up this finding. Men who had sniffed real tears had less activity in parts of the brain linked to sexual excitement.
The experiment was double-blind—neither the subjects nor the scientists knew which liquid was which—a technique considered especially strong in research science.
Lower Sex Drive Just Part of the Story?
Sobel cautioned that, so far, this trail of tears may be leading his team to only part of the story.
For instance, it's possible that the men's lack of sex drive is just a side effect of the drop in testosterone provoked by the tear chemical—and the signal is perhaps really meant to reduce aggression.
In evolutionary terms, the ability to control aggression in another animal can have major value, Sobel pointed out.
A"beautiful example"in the animal world involves blind mole rats, some of which emit tears and rub them all over their bodies—a strategy that seems to keep hostile mole rats at bay, he said.
"It's like it's protecting itself against aggression. I'm willing to bet that's perhaps a similar picture {to what} we're seeing here,"said Sobel, whose study will be published tomorrow in the journalScience.
Sobel noted that the tear signaling is likely not tied to gender, but rather to dominance: Less dominant people may be sending aggression-reducing messages to stronger individuals via their tears.
His team next plans to replicate their study with men's tears.
Women's-Tears Study Needs"Excavating"
The tears study is a"very powerful"development, saidMartha McClintock, founder of the Institute of Mind and Biology at the University of Chicago and a pioneer in human chemosignal research.
(Related:"Pheromone in Urine Spurs Mating in Elephants.")
But McClintock cautioned against speculating too early about what the tear chemosignals may be saying.
"We need to excavate it some more—you know there's something there but don't know the full shape of it and how it works,"she said.
"Now let's look to see what are the effects of men's tears and babies' tears and grandparents' tears— what's the effect on people at all different stages of their lives,"she added.
"Let's not just stop and say this is something that's only important in a sexual context."
