Quasars, those super-bright light sources in space, are much more common than anyone thought.
It's just that we haven't been able to see them.
(Image: Examples of strongly interacting/merging galaxies containing a heavily obscured growing supermassive black hole nearby (top panels) and in the early Universe (bottom panels), as observed by the Hubble Space Telescope. Source: University of Hawai'i Institute for Astronomy.)
Like the lights of a city obscured by fog, a new study by astronomers—including ones from the University of Hawai'i—shows that many of them are obscured by vast clouds of interstellar dust.
The study was led by Ezequiel Treister from the University of Hawaii, and published in journal Science March 25.
First, some overly simple definitions.
At the center of activity is a black hole, a super-compact, super-dense phenomenon that sucks in everything around it, including light.
But as matter is sucked in, before the black hole takes complete control, the matter speeds up, experiences friction, and releases large amounts of radiation. You can't detect the black hole direction, but you can detect the radiation around it.
When a black hole collides with, and sucks up a big gas cloud, the energetic process releases lots of radiation, including light—creating a quasar.
Quasars used to be thought of as relatively rare. Not any more.
Now, it turns out that many of the youngest black hole-quasar combinations are difficult to see because they are obscured within immense clouds of dust. Over time, like a fog being cleared by the wind, the dust is blown away, revealing the quasar inside.
Said Treister: "We find that these growing black holes are originally hidden by large amounts of dust, but after 10-100 million years this dust is blown out by the strong radiation pressure, leaving a naked quasar, that is visible in optical wavelengths and keeps shining for another 100 million years.”
The project used combined data from the Hubble, Chandra and Speitzer space observatories to detect the signals of quasars inside dust clouds. One finding: obscured quasars were much more common in the early universe than they are now.
The paper's authors are Treister, an Einstein postdoctoral fellow at the University of Hawaii, Priyamvada Natarajan of Yale, David Sanders of the University of Hawaii, Meg Urry and Kevin Schawinski of Yale and former University of Hawaii's graduate student Jeyhan Kartaltepe, who is now with the National Optical Astronomy Observatory.
© Jan TenBruggencate 2010
Saturday, March 27, 2010
Quasars, those super-bright light sources in space, are much more common than anyone thought.
Wednesday, March 24, 2010
In a wonderfully confusing tale, an island in the Bengal Sea has disappeared.
The world community doesn't know what to make of it. Some are blaming its disappearance on climate change and rising sea levels.
There is no doubt that sea levels are rising, but the death of New Moore Island can't reasonably be blamed directly on that. (The ephemeral isle is known in Bangladesh as South Talpatti, and to some Indians as Purbasha.)
The island reportedly was six feet above sea level a couple of decades ago, and even at the highest estimated rate of rise, it should only be down to 5-foot-10 or 11 today. But some scientists are happy to blame sea level changes, which reportedly have been troublesome in the Bay of Bengal.
The BBC quotes Professor Sugata Hazra of the School of Oceanographic Studies at Jadavpur University in Calcutta, who said his own research indicates sea levels have been rising much faster since the turn of the century than in years earlier.
And it is reported elsewhere that New Moore only popped above the waves in the 1970s, and it was never much of a land mass, although India and Bangladesh have been fighting over title to it. But other sources suggest it may have existed for decades earlier.
Apparently its appearance followed a tropical rotating storm, Cyclone Bhola of 1970, suggesting it may be, at best, an emergent sand bar, like ones that occur in Kane'ohe Bay and elsewhere in Hawai'i. It lies roughly in the middle of a channel between India and Bangladesh.
Clearly there's something strange going on in the Bay of Bengal, where another island, Lohachara, sank in 1996, and the island of Ghoramara is half under. Our guess: that sea level changes are indirectly to blame, by changing erosion patterns that can cause delta islands like these to quickly disappear.
© Jan TenBruggencate 2010
Friday, March 19, 2010
There's not much evidence of significant impacts on beaked whales from Navy sonar activity in Hawaii, but does that mean there aren't such impacts?
Not necessarily, according to a new paper.
The beaked whales most commonly implicated are Cuvier’s (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales. For more information see here. And here.
(Image: A juvenile Blainville's beaked whale off Hawai'i in 2008 with suction-cup attached time-depth recorder. The suction device stayed attached about two hours, providing information about dive depth and other behavior. Credit: Robin Baird .)
Meghan Faerber, of the University of Wales in Great Britain, and Robin Baird, of Cascadia Research Collective in Olympia, Washington, asked the question:
“Does a lack of observed beaked whale strandings in military exercise areas mean no impacts have occurred? A comparison of stranding and detection probabilities in the Canary and main Hawaiian Islands.”
They point out that strandings of beaked whales during naval activity are more common in the Canaries than in Hawai'i. But they caution that it doesn't mean there aren't impacts in the Hawaiian Islands. They cite an old dictum: “The absence of evidence (of an impact) is not evidence of absence.”
There have been 11 documented mass strandings in the Canaries, six of which are associated with Naval exercises.
Meanwhile, “The Hawaiian Islands experience regular naval exercises and contain resident beaked whale populations. Only nine beaked whale strandings have been documented in the Hawaiian Islands through 2007 , and no mass strandings have been reported.”
Since there does seem to be a link between naval sonar and whale strandings elsewhere, the authors are unwilling to assume that there would be no link in the islands. Rather, it's possible, they say, that the impacts are being missed due to unique factors in Hawai'i.
They argue that beaked whale habitat may be farther from shore in the Hawaiian Islands, that reefs and scavenging sharks, as well as current patterns, may prevent injured whales from appearing on the shore in Hawai'i,
Their point: “It cannot be concluded that the lack of mass strandings in Hawai‘i is evidence of no impact.”
Which of course puts the Navy in a difficult position of attempting to address an assertion for which there is little evidence.
© Jan TenBruggencate 2010
Friday, March 12, 2010
New research is suggesting you can get much more health benefit in much less time by using bursts of increased intensity.
This flies in the face of lots we've learned in the past generation about exercise and health--that you need to put in the time for good overall fitness. Indeed the researchers concede that their work needs to be expanded upon.
The new paper is entitled “A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms.” Its authors are Jonathan Little, Adeel Safdar, Geoffrey Wilkin, Mark Tarnopolsky and Martin Gibala, most of whom are with McMaster University in Hamilton, Ontario, Canada. It's in the March 15, 2010, The Journal of Physiology, a publication of The Physiological Society.
For those of us who exercise regularly and are also challenged for time, this is exciting stuff. Our own exercise credentials include track running, marathons and triathlons, some bike racing and both long and short-distance canoe paddling, and a little time coaching at various sports.
The amazing benefits of bursts of intensity, whether through the various forms of interval or fartlek training, are certainly clear. They can turn a middle-of-the-pack athlete into a contender within weeks, presuming a good base of aerobic training.
The suggestion of the new research seems to be that the base of long distance is not needed—at least for good muscle tone.
The Canadian team had earlier shown that extreme-intensity bursts were beneficial. The newest work indicates important health benefits even from high-intensity intervals that are well short of extreme.
Here is one release on the report, written by the publisher's Mary Arbuthnot. She says that a new study “adds to the growing evidence for the benefits of short term high-intensity interval training (HIT) as a time-efficient but safe alternative to traditional types of moderate long term exercise.” Another release by Jane Christmas of McMaster University, is here.
Author Gibala, who is chair of the McMaster Department of Kinesiology, says that "Doing 10 one-minute sprints on a standard stationary bike with about one minute of rest in between, three times a week, works as well in improving muscle as many hours of conventional long-term biking less strenuously."
Not to be a naysayer, but that's still 20 minutes of training, three times a week, which pretty much fits in with traditional recommendations for basic fitness. But for advanced fitness?
The latest study used standard exercise bikes, and had subjects pedal at 95 percent of maximal heart rate during their bursts. (Maximal heart rate is determined during a supervised cardiac stress test, but for a general number, subtract your age from 220, to get your maximum heart rate.)
After six training days over a two-week period, the interval training subjects had comparable results to those doing longer-time, but lower-intensity workouts: “improved exercise performance and muscular adaptations that are linked to reduced risk of diseases such as Type 2 diabetes,” the McMaster release said.
The scientists argue that exercise of one type or the other may allow individuals to function with less risk of heart attack, diabetes or stroke.
In his initial work, published in 2006, Gibala conducted research using young, active individuals, and used intervals in which they exercised as hard as they could. Here's Gibala's own report:
“Sixteen young men performed six training sessions over two weeks. Eight subjects performed between four and six 30-second bursts of 'all out' cycling separated by four minutes of recovery during each training session. The other eight subjects performed 90-120 minutes of continuous moderate-intensity cycling. Total training time commitment including recovery was 2.5 hours in the sprint group, whereas the endurance group performed 10.5 hours of total exercise over two weeks. Both groups showed similar improvements in exercise performance and the muscle's ability to resist fatigue.
"Our study confirms that interval-based exercise is indeed a very time-efficient training strategy. It is a demanding type of training and requires a high level of motivation, however it might be the perfect option for those who say they have no time to exercise."
In his own press release at that time, Gibala said, “"The most striking finding from our study was the remarkable remarkably similar adaptations induced by two such diverse training strategies.”
Here is a 2007 paper in which Gibala describes his results and comments on their health impacts.
It is not clear from this research whether these techniques also provide a short-time way to train for endurance events like long canoe races, long bike races or marathons and triathlons.
And it is not clear whether these short workouts provide larger health benefits, beyond providing strong skeletal muscles. Write the authors: “Future research should examine whether practical low-volume HIT can improve markers of metabolic health in healthy individuals and those at risk of developing chronic inactivity-related disease to determine whether this type of training is an effective health-enhancing exercise strategy.”
Some companies use Gibala's work to promote programs that use exceedingly short workouts of four to six minutes. But it is clear that his workouts are running 20 minutes or longer, whether they're 4 to 6 extremely intensive half-minute bursts with four-minute breaks or 10 less intensive one-minute bursts with one-minute breaks.
© Jan TenBruggencate 2010
Monday, March 8, 2010
You won't find many candidly political positions on this site, but here's one:
For those readers on Kauai, I'm running for the board of our island's electric utility, the Kauai Island Utility Cooperative, KIUC. And I'd appreciate your vote.
I'm Jan TenBruggencate, the guy pictured here. If you're a regular reader, you know I'm interested in energy efficiency, alternative energy, the impacts of using oil almost exclusively for power, as well as social justice.
If you get an electric bill on Kauai, this week you'll receive a ballot. Your choice can be made by mail, by phone or by email. There are five of us running for three board seats. It's a three year term. See more information here. http://www.kiuc.coop/
One of the first questions people ask is, “Are you nuts?” Besides the fact that several people in the utility and in the energy community urged me to run, I had my own impetus. After a career as a newspaper writer prohibited by ethical concerns from participating actively in the community, I feel the need—even the requirement—to “pay back.” So I'm serving on a community board and a county commission, and now the KIUC bid.
“Gosh, you've turned into a citizen,” said a friend and former co-worker.
Another common question, “Are you committed.”
That normally means, “What are you doing personally?” Well, I ride a bike. We have a photovoltaic system. I've got energy efficient lights and appliances at home. I recycle like crazy.
But sometimes "Are you committed," means committed to community, which is code for, "Just how local are you?" I've lived on Kauai for nearly 40 years, and was raised on a Molokai pineapple plantation, but not born here. My degree is from UH. I have worked from every one of the main Hawaiian Islands, and also some smaller ones, including Niihau, Kahoolawe, Nihoa, Laysan, Midway and Kure. I not only paddle but build outrigger canoes.
I have been fortunate enough to be one of three candidates nominated by the citizen panel that votes as the KIUC Nominating Committee. I've also been endorsed by the energy efficiency and conservation group, Apollo Kauai.
I can't promise much beyond careful attention, hard work and an open mind. I like to think that years as a reporter, much of it covering science, have given me a capability to conduct research, to assess opportunities and challenges, and to judge alternatives.
My goals if elected, are:
--work to ensure reasonable rates and reliable service
--to promote efficiency and renewable energy, while reducing oil dependence
--to do it as cost-effectively as possible, using the best technology available, while protecting the environment
--to ensure that rates and policies are fair to all segments of the population
Kauai's energy future faces big challenges. Just a generation ago, half our power was produced from local renewable resources—bagasse and hydroelectric power. Today we are roughly 90 percent dependent on imported oil for our power. This gives us little control over supply and electricity costs, and makes our energy future vulnerable.
A significant portion Kauai's electricity costs is tied to the global oil prices. We were paying 35 cents a kilowatt a few years ago. We paid nearly 50 cents at one point in 2008 when oil nearly reached $150 a barrel. It dropped into the 25 cent range last year, and recently it was more than 35 cents again.
A 2008 KIUC membership survey said residents want reasonable rates and good value. Our citizens can't budget for energy prices that swing so widely. In order to gain control of our rates we need to shed our vulnerability to oil.
Although these are challenging times it is also a time of new opportunities for KIUC. There's lots going on. We have federal financial help to upgrade our metering infrastructure. Conservation and efficiency technologies are maturing, and we need to do more in this area. New building standards will moderate the increase in energy demand. And in both the short term and the long, there are several renewable energy production technologies in active discussion or development.
The issues we face are difficult ones, but our community has the benefit of the cooperative form of utility ownership. We are all in this together. We all own this electric utility, and we all must take a part. We are stronger because of the breadth of ideas in our extensive community, and I can assure you that I'll be listening.
I will be happy to respond to any questions. You can reach me at email@example.com. This campaign depends on your spreading the word—if you believe I can do a good job, please talk to your friends and neighbors, ask them to vote when the ballot arrives.
Thanks very much.
Sunday, March 7, 2010
A research team studying global impacts of climate change has found that Hawai'i will generally have few major disruptions, although weaker trades could reduce rainfall.
Much of the rest of the world may see dramatic changes in rainfall, in temperatures, in storm frequencies, but the Islands appear to be in a kind of mid-Pacific sweet spot.
That's one conclusion from a paper, Global Warming Pattern Formation: Sea Surface Temperature and Rainfall, by Shang-Ping Xie and Jian Ma of the University of Hawai'i School of Ocean and Earth Science and Technology's International Pacific Research Center, along with Clara Deser and Haiyan Teng of the National Center for Atmospheric Research, and Gabriel Vecchi and Andrew Wittenberg of the NOAA Geophysical Fluid Dynamics Laboratory.
Their paper was published in the Feb. 15, 2010, "Journal of Climate" of the American Meteorological Society. It uses a range of climate models to study potential changes in global weather patterns.
It's a complex paper, but among its conclusions:
With the anticipated changes in global temperatures over the coming half century, rainfall for Hawai'i will probably not be significantly impacted. Maybe some reduction in rain overall, maybe some local changes depending on specific geographic features like mountains and valleys.
Other studies have suggested a slight reduction in rainfall in the Islands.
Xie and co-authors do see a weakening of tradewind flow, which could result in some reduction in Hawai'i rainfall. Depending on when it occurs, it could also change the comfort levels for people living in the Islands.
The researchers find that tropical storm frequency will not change significantly in Hawaiian waters.
One of the key piece of information—and this has been a big feature of recent debate over climate change—is that while warming is occurring, it's not distributed evenly across the globe.
As an example, while Hawai'i's changes are comparatively minor, the models suggest significant increases in rainfall in the Intertropical Convergence Zone to the south of the Islands. And while our storm frequency is not anticipated to change much, the hurricanes in the Pacific south of the equator are expected to be more common, in association with significant warming of the ocean in that area.
For Samoa, the Cooks, French Polynesia and other nations in that part of the sea, that's not good news.
© Jan TenBruggencate 2010
Thursday, March 4, 2010
They began a reforestation effort whose impacts can still be seen today. Much of the reforestation was with hardy and often fast-growing imported species, like eucaluypts, pines, silver oak and others.
(Image: Degraded pasturelands in 1940 on the Edwards Plateau in Texas, where spring flows revived after woody plants were allowed to return. Credit: Charles Taylor and American Geophysical Union.)
The reforestation theory, in part, is that the trees shade the ground, reducing evaporation, and reduce ground-level wind, further reducing evaporation. That gives rainfall an opportunity to soak into the ground and recharge groundwater supplies.
But there have been naysayers who suggest that trees actually suck water out of the ground more than they preserve.
The correct answer, as often is the case, may be that it depends. Not all trees are created equal as protectors of the watershed. And some dryland species like kiawe and tamarisk have been accused of sending down deep roots that suck up groundwater. A welldigger once told me that you could actually see the impact of kiawe on water supplies, causing groundwater levels to drop as soon as the sun rose and the trees started the process of evapotranspiration.
But a complex forest with trees and shrubs does appear to significantly improve an area's water retention.
And not only in Hawai'i.
A new paper to be published by the American Geophysical Union's Geophysical Research Letters says that groundwater levels improved dramatically in Texas after severely overgrazed lands were better managed. http://www.agu.org/news/press/pr_archives/2010/2010-06.shtml
The study says that an “analysis of many decades of historical records for four central Texas river basins challenges widespread perceptions that woody plants have the opposite effects on streams and aquifers.”
Bradford Wilcox of Texas A&M University and Texas AgriLife Research, and former Texas A&M graduate student Yun Huang studied the Edwards Plateau, whose Edwards aquifer provides much of the water for San Antonio. The semi-arid plateau had been overgrazed for a century starting about 1880.
But when stocking rates were reduced, and trees and shrubs came back, they saw a change.
“These landscapes are recovering, but they’ve also converted to woody plants. We’re also seeing large-scale increases in the amount of spring flows. This is opposite of what everybody is presuming —[which is that] the trees are there sucking up all of this water. The trees are actually allowing the water to infiltrate,” Wilcox said.
The flow of water from springs has doubled since before 1950, and the flows in three of the region's four rivers has increased in the same period, they said.
These results will not be a shock to anyone who has walked under the cool shade of the native forest in The Nature Conservancy's Kanepu'u reserve on Lana'i, and then compared the environment to the sun-baked, eroded environment outside the fenced reserve.
© Jan TenBruggencate 2010