Black Holes

Like gluttonous piranhas, supermassive black holes in young galaxy clusters gorge on bountiful gas until little fuel is left, and then they fade away, a new study suggests.
 

Using NASA's Chandra X-ray Observatory, astronomers tallied the number of rapidly growing supermassive black holes, called active galactic nuclei, or AGN, in two populations of galaxy clusters.

One group consisted of young-looking clusters located very far from Earth, and the other consisted of an older group located closer to us.

The results of the survey, detailed in the July 20 issue of The Astrophysical Journal Letters, showed that the more distant, younger clusters contained about 20 times more AGN than nearer ones.

Fade with time

The implication, said study team member Paul Martini of Ohio State University, "is that when clusters were young, there were much more AGN present in the cluster galaxies. As the clusters galaxies continued to evolve, the AGN faded away."

By this reasoning, the researchers predict that clusters with ages between the two groups studied would have an intermediate amount of AGN, while older clusters would have even more AGN.

As clusters age, less gas fuel is available for their AGN to consume and they become less active. "Really it's the activity of the black hole that has faded away," Martini told SPACE.com. "The black hole is still there and the galaxy is still there as well. It's just the activity that we see from the black hole has diminished a great deal."

Galaxies that are not part of clusters have a constant, if slow, trickle of intergalactic gas falling onto them, which they use to replenish their gas reserves and continually form new stars. The spaces between galaxies that are part of clusters, however, are filled with hot, rarified gas that does not get incorporated into the individual galaxies very efficiently.

Starving galaxies

"There's no freshening of the gas in the cluster galaxies themselves," Martini said.

As a result, galaxies in clusters become starved of gas over time, and black hole activity and star formation in these galaxies slows.

An average-sized galaxy contains about 100 billion stars, and a single galaxy cluster contains several hundred galaxies. However, only a few of the cluster's galaxies contain AGN.

All of these objects-stars, black holes, galaxies and galaxy clusters-can crash and merge with one another. When clusters collide, the amount of energy generated is second only to the Big Bang event scientists think gave birth to the universe.

Antimatter
Like Superman's alter-ego, Bizzaro, the particles making up normal matter also have opposite versions of themselves. An electron has a negative charge, for example, but its anti-matter equivalent, the positron, is positive. Matter and anti-matter annihilate each other when they collide and their mass is converted into pure energy by Einstein's equation E=mc2. Some futuristic spacecraft designs incorporate anti-matter engines.

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Mini-Black Holes
If a radical new "braneworld" theory of gravity is correct, then scattered throughout our solar system are thousands of tiny black holes, each about the size of an atomic nucleus. Unlike their larger brethren, these mini-black holes are primordial leftovers from the Big Bang and affect space-time differently because of their close association with a fifth dimension.

Cosmic Microwave Background
Also known as the CMB, this radiation is a primordial leftover from the Big Bang that birthed the universe. It was first detected during the 1960s as a radio noise that seemed to emanate from everywhere in space. The CMB is regarded as one of the best pieces of evidence for the theoretical Big Bang. Recent precise measurements by the WMAP project place the CMB temperature at -455 degrees Fahrenheit (-270 Celsius).

Dark Matter
Scientists think it makes up the bulk of matter in the universe, but it can neither be seen nor detected directly using current technologies. Candidates range from light-weight neutrinos to invisible black holes. Some scientists question whether dark matter is even real, and suggest that the mysteries it was conjured to solve could be explained by a better understanding of gravity.

Exoplanets
Until about the early 1990s, the only known planets in the universe were the familiar ones in our solar system. Astronomers have since identified more than 190 extrasolar planets (as of June 2006). They range from gargantuan gas worlds whose masses are just shy of being stars to small, rocky ones orbiting dim, red dwarfs. Searches for a second Earth, however, have so far turned up empty. Astronomers generally believe that better technology is likely to eventually reveal several worlds similar to our own.

Gravity Waves
Gravity waves are distortions in the fabric of space-time predicted by Albert Einstein's theory of general relativity. The waves travel at the speed of light, but they are so weak that scientists expect to detect only those created during colossal cosmic events, such as black hole mergers like the one shown above. LIGO and LISA are two detectors designed to spot the elusive waves.

Galactic Cannibalism
Like life on Earth, galaxies can "eat" each other and evolve over time. The Milky Way's neighbor, Andromeda, is currently dining on one of its satellites. More than a dozen star clusters are scattered throughout Andromeda, the cosmic remains of past meals. The image above is from a simulation of Andromeda and our galaxy colliding, an event that will take place in about 3 billion years.

Neutrinos
Neutrinos are electrically neutral, virtually mass-less elementary particles that can pass through miles of lead unhindered. Some are passing through your body as you read this. These "phantom" particles are produced in the inner fires of burning, healthy stars as well as in the supernova explosions of dying stars. Detectors are being embedded underground, beneath the sea, or into a large chunk of ice as part of IceCube, a neutrino-detecting project.

Quasars
These bright beacons shine to us from the edges of the visible universe and are reminders to scientists of our universe's chaotic infancy. Quasars release more energy than hundreds of galaxies combined. The general consensus is that they are monstrous black holes in the hearts of distant galaxies. This image is of quasar 3C 273, photographed in 1979.

Vacuum Energy
Quantum physics tells us that contrary to appearances, empty space is a bubbling brew of "virtual" subatomic particles that are constantly being created and destroyed. The fleeting particles endow every cubic centimeter of space with a certain energy that, according to general relativity, produces an anti-gravitational force that pushes space apart. Nobody knows what's really causing the accelerated expansion of the universe, however.

Russia will use satellites to catch loggers felling its vast Siberian forests known as the "green lungs of the planet," the state forestry agency said on Wednesday.
 

Ancient taiga woodlands which cover much of Siberia are protected by Russian law, but since the 1991 collapse of the Soviet Union illegal loggers have cut down millions of trees, mainly for sale in neighboring China.

"From January 1 2008 we will have continual protection," Vladimir Kresnov, head of the Russian forestry agency, said at a news briefing.

"The government has to know everything about its rich forests and has to have correct information about the state of its forest resources."

Scientists often refer to the taiga forest, which stretches across Siberia from the Urals on the boundary of Europe to the Pacific in the Far East, as the "green lungs of the planet."

Ecologists welcomed the satellite protection plan.

"It will definitely help defend parts of the forest," Yevgeny Shvarts, conservation policy director at WWF Russia, said.

The announcement by the agency, which is controlled by the Ministry of Natural Resources, comes as environmentalists fight to save forests around the 2014 Winter Olympics venue in Sochi on the Black Sea coast in southern Russia.

The Russian Ministry for Economic Development, which is controlling construction for the Games, wants to concrete over woodland to build the Olympic village and a bobsleigh track on the edge of a protected natural park.

ON THE RIO GRANDE, Texas (Reuters) - The riot of green vegetation that lines both sides of the Rio Grande river along the southeast Texas and Mexican border can give a canoeist the impression of gliding past unbroken wilderness.
 

But the strip of riparian forest that runs a few miles between the Texas towns of Fronton and Roma is deceptive.

In reality one of the most ecologically diverse corners of the United States has been diced up by farming and urban sprawl into isolated fragments of habitat that support far less wildlife than when they were whole.

Now, conservationists are concerned that a planned border security fence to stem illegal immigration from Mexico could cut this delicate area up even more and possibly remove the corridor of vital riverbank habitat that remains.

"We know as habitats become fragments whether by roads, fences or walls animals become much less capable of roaming widely," said Dr. Joel Berger, a senior scientist with the New York-based Wildlife Conservation Society.

"As these restrictions occur animals become isolated and with isolation the risks of local extinctions greatly increase," he said.

Animals at risk of local extinction include the U.S. population of the ocelot, a wild cat that is down to a few dozen animals, and several species of birds. Rare native plants such as sabal palm trees are down to a few isolated patches.

Driving along Route 281 which hugs this section of the Rio Grande reveals what lies behind the forested facade on the river's edge -- fast-growing border towns and cultivated fields of corn, sugar cane and other crops.

At stake is the sheer diversity of life in a region of lush subtropical vegetation threaded by a great river, lying between vast arid landscapes to the west and the Gulf of Mexico to the east.

Few Americans are aware of the area's ecological significance, which in four counties includes 300 butterfly species -- more than the rest of the country east of the Mississippi -- and over 500 different birds.

RECONNECT THE DOTS

Ecologists are trying to reconnect the dots by revegetating old farmland with native plants which they hope to link up.

At the Nature Conservancy of Texas' 1,000-acre Southmost Preserve, the contrast is plain along a dirt road with a cornfield on one side and wild bush on the other.

"This side looked exactly like that cornfield seven years ago," said Lisa Williams, a local project director with the Nature Conservancy, as she pointed to the tangle of wild growth which included haunting tepegauje trees -- a key species of the area -- their feathery leaves blowing in the wind.

"These are the pearls in a necklace which we are trying to string together," she said.

A pair of coyotes ran furtively through a field while a coot, an aquatic bird, chattered from a wetland.

When ecologists look at a patchwork of ecosystems cut up by roads or farms they think of islands -- and like islands out to sea, their isolation can be the undoing of their inhabitants.

According to the World Conservation Union, about 800 species have become extinct since 1500, when records began. Most were on islands.

But scientists say that extinctions and steep local population declines are now creeping onshore because continental habitats are being diced up by human activities.

Isolation makes populations more prone to sudden die-offs from disease or drought and also limits their genetic pool.

Other tracts of land besides Southmost are being protected in the area and reverted to their original state -- but there are worries the wall could cut through some of this work.

"There are two dozen species of very specialized birds that only live in the river forest and if that was cleared for the wall they will be lost to the area," said Martin Hagne, the executive director of the Valley Nature Center.

Supporters of the wall say it is needed to stem the tide of illegal immigration into the United States and the government says one green spin off will be a reduction in the mountains of litter which illicit crossers leave behind.

"I think it's well documented the affect that illegal border crossing activity has on the environment. The result in many cases is refuse left behind such as plastic bottles, clothes and discarded rubber rafts," said Michael Friel, a spokesperson for U.S. Customs and Border Protection.

He also said that in areas where effective control of the border has been reasserted such as near San Diego, local wild habitat which was trampled by illegal crossers has re-grown.

Elsewhere international fences are being dropped for conservation reasons. The fence between South Africa's famed Kruger National Park and Mozambique is being removed to make more room for elephants and other wildlife.

Imagine answering your cell phone to hear your Scotch Moss plant telling you in a fake Glaswegian accent that it needs a drink.
 

This scenario is not far from reality with a group of postgraduate students at New York University developing a way for over-watered or dry plants to phone for help.

The "Botanicalls" project uses moisture sensors placed in the soil which can send a signal over a wireless network to a gateway that places a call if the plant's too dry or wet.

Recorded voices are assigned to each plant to match its biological characteristics and to help increase the charm of the phone message and give plants their own personality.

Interactive communications student Rebecca Bray, who developed the concept with three colleagues, said the technology was not new but it's the way of communicating by voice and adding personality to the plants that's different.

"They will call and tell you they are thirsty and need a lot of water. They are also really polite," Bray told Reuters.

"We wanted to make sure that you weren't just getting phone calls that were really needy. So we have them calling you back when you've watered them to say thank you for watering me."

For example, the Scots Moss is given a fake Scottish accent as it was not originally from Scotland despite its name. A prolific spider plant was given a cheerful, friendly voice.

"We wanted to provide a system so that the plants could actually survive by communicating to people," said Bray who developed the system with Rob Faludi, Kati London and Kate Hartman.

She said they were surprised how many people have approached them to acquire this service for homes and businesses but didn't expect the system to become available commercially for at least another six months.

"We hope that the system will help people learn how to take better care of their plants over time and maybe not even need the phone calls after a while," Bray said.

Old Alaskan oil wells could be swallowed by the ocean as rising temperatures speed up erosion of the state's Arctic coastline.
 

The disappearance of sea ice that shields against storm-waves, and of permafrost that holds shorelines together, is eating away at the coast of the National Petroleum Reserve-Alaska, according to a U.S. Geological Survey study.

Erosion rates have risen steeply along the coastline of the reserve -- where the administration of President George W. Bush wants to increase oil drilling -- possibly due to warmer weather, the study showed.

"Coastal erosion has more than doubled along a segment of the Arctic Alaska coast during the past half century," it said, adding the land loss was being magnified by the conversion of freshwater "thermokarst" lakes into saltwater bays as they become inundated with waters from the Arctic Ocean.

"There's a warming trend in Alaska, and that's documented," said John Mars, primary author of the study. "We think that that is related to what we're seeing."

The Bureau of Land Management, which oversees the reserve, has identified about 30 old oil exploration wells that need to be cleaned and plugged before the sea claims them.

"Hopefully we'll get all of these wells before anything happens," said Sharon Wilson, spokeswoman for the BLM's Alaska regional office.

CLEANING UP

The BLM has already cleaned and plugged the J.W. Dalton well in 2005 after more than 300 feet of shoreline was eaten away in a single summer. That well, drilled in 1979, is now underwater.

"There was sort of a mass failure in terms of the land that just melted away," said Wayne Svejnoha, a BLM scientist, adding the cleanup is expected to cost around $20 million per well.

Cleanup is planned next year for a 1976 well on the east side of Teshekpuk Lake, Svejnoha said, although a waste pit has been breached and may be leaking pollutants into the lake.

Environmentalists find it ironic that BLM is on the verge of authorizing new oil developments in the Teshekpuk wetlands.

"On the one hand, they're having to scramble and clean up old wells that may soon be covered by water. And on the other hand, they may be proposing to expand that oil-field infrastructure in the same area," said Stan Senner, executive director of Audubon Alaska.

He and others oppose BLM plans for new exploration along Teshekpuk Lake, a potentially oil-rich area but also critical to migrating geese, caribou and other Arctic wildlife.

But Svejnoha said new oil drilling would lack some erosion-related environmental risks. Operators no longer store drilling waste in pits next to wells, eliminating the specter of such pits unleashing their contents into the sea, he said.

Coastal erosion is among the climate impacts -- such as reduced periods for hard-frozen tundra and solid sea-ice cover -- that environmentalists say makes North Slope oil operations riskier than before.

More than oil sites are affected by erosion, with sections of the North Slope's sole highway at risk, as well as abandoned defense communications structures built early in the Cold War -- many of which have associated hazardous-waste stockpiles.

TAMPA, Fla. - Prison inmates are getting a present from the state of Florida: playing cards. For detectives looking to solve dozens of cold cases, it's the start of a game of Go Fish that might pay off big.
 

On Tuesday, Florida's nearly 93,000 state inmates started getting one of two decks that between them highlight 104 of the state's most troubling unsolved murder and missing persons cases.

"What better way to get them talking than to have cards with the cases on them?" said Special Agent Tommy Ray of the Florida Department of Law Enforcement. "These are people who have been in there for years. That's the best source of information. There are a couple of high-profile cases I think we'll get solved."

Ray helped launch the statewide program after he and colleagues on a cold case squad in Polk County got the idea to produce a similar deck for county inmates there in 2005. They were inspired by the famous most-wanted deck of Saddam Hussein and other fugitives issued to U.S. troops shortly after the 2003 invasion of Iraq.

Soon after the Polk County cards were issued, they generated a tip. Two men have been charged with murder in the 2004 killing of one of the victims on the cards, Thomas Wayne Grammer.

Other law enforcement agencies have caught on. Authorities in San Diego, Kansas City, Mo., and Odessa, Texas, are among those who have created their own decks, and Ray said he has gotten inquiries from as far away as Australia.

For the state program, authorities printed 85,000 decks featuring the first 52 cases, and started handing them out Tuesday to inmates at Wakulla Correctional Institution in the Panhandle town of Crawfordville. In a few weeks, 15,000 decks with 52 different cases will be distributed.

The King of Spades in one deck is Tiffany Sessions, a 20-year-old University of Florida sophomore who disappeared on Feb. 9, 1989. The Queen of Diamonds in that deck is 12-year-old Jennifer Odom, a Pasco County girl whose body was found on Feb. 25, 1993, six days after she disappeared.

Sessions' card features her smiling face. Odom's card has a picture of a sweat shirt and her book bag because authorities didn't want to give the state's sex offenders pictures of children.

The state attorney general's Crime Stoppers Fund is paying the $75,000 cost of the program — about $68,000 to produce the cards and $7,000 for rewards, an agency spokeswoman said. The Polk County deck was produced with help from the local Crime Stoppers program.