Dark matter in the inner Milky Way

A simulation of the dark matter structure in the universe. This image covers an area of 20 megaparsecs, or about 1.3 billion light-years. By contrast, our Milky Way galaxy is thought to be about 100,000 light-years across. Image via CfA.

We knew there was dark matter in the outer part of the Milky Way. In fact, the dark matter surrounding our galaxy and other spiral galaxies is what first cued astronomers to the existence of this mysterious substance – now known to make some 26% of the entire universe – in 1978. Now a new study is providing evidence for the presence of dark matter in the innermost part of the Milky Way. There may even be dark matter lurking in our own solar system, and, if so, maybe today’s dark matter detectors will find it. The study – announced February 9, 2015 by University of Stockholm – claims to have demonstrated that large amounts of dark matter exist around us, and also between us and the center of our Milky Way galaxy. The Stockholm astronomers said this week in a statement:

The result constitutes a fundamental step forward in the quest for the nature of dark matter.

In the 1970s, astronomers Vera Rubin and Kent Ford discovered dark matter accidentally. They were looking at spiral galaxies and noticed that stars far from the galactic centers, in the sparsely populated outer regions, were moving just as fast as those closer in. This was unexpected. The visible mass of a galaxy doesn’t have enough gravity to keep such rapidly moving stars in those sorts of orbits. Thus the astronomers were faced with a startling conclusion. There is more to galaxies than meets the eye, a tremendous amount of unseen matter in the outer regions of galaxies where visible stars are relatively few.

That was a powerful step forward in our understanding of the universe, and, since then, astronomers have gotten very good at inferring the existence and properties of dark matter from its gravitational effects on visible matter and radiation. Indeed, the large-scale structure of the universe itself is thought to be driven in large part by dark matter. However, no one has yet detected dark matter directly. We can only infer that it exists, not know that it does.

What’s more, it been very difficult to establish that dark matter exists not only on the outskirts of the Milky Way, but also in the inner part of the galaxy, where our Earth and sun reside. That’s because our measurements – the same sorts of measurements used to find dark matter in the first place – have not been precise enough to reveal dark matter from our own position in the Milky Way. Miguel Pato at the Department of Physics at Stockholm University said:

In our new study, we obtained for the first time a direct observational proof of the presence of dark matter in the innermost part of the Milky Way.

We have created the most complete compilation so far of published measurements of the motion of gas and stars in the Milky Way, and compared the measured rotation speed with that expected under the assumption that only luminous matter exists in the galaxy.

The observed rotation cannot be explained unless large amounts of dark matter exist around us, and between us and the galactic center.

Our method will allow for upcoming astronomical observations to measure the distribution of dark matter in our galaxy with unprecedented precision. This will permit to refine our understanding of the structure and evolution of our galaxy, and it will trigger more robust predictions for the many experiments worldwide that search for dark matter particles. The study therefore constitutes a fundamental step forward in the quest for the nature of dark matter.

Bottom line: Astronomers in Stockholm say their new technique has revealed dark matter in the inner Milky Way galaxy, including the area in which our sun and Earth reside.

Via Science Daily

from EarthSky http://ift.tt/16UgsJs

A simulation of the dark matter structure in the universe. This image covers an area of 20 megaparsecs, or about 1.3 billion light-years. By contrast, our Milky Way galaxy is thought to be about 100,000 light-years across. Image via CfA.

We knew there was dark matter in the outer part of the Milky Way. In fact, the dark matter surrounding our galaxy and other spiral galaxies is what first cued astronomers to the existence of this mysterious substance – now known to make some 26% of the entire universe – in 1978. Now a new study is providing evidence for the presence of dark matter in the innermost part of the Milky Way. There may even be dark matter lurking in our own solar system, and, if so, maybe today’s dark matter detectors will find it. The study – announced February 9, 2015 by University of Stockholm – claims to have demonstrated that large amounts of dark matter exist around us, and also between us and the center of our Milky Way galaxy. The Stockholm astronomers said this week in a statement:

The result constitutes a fundamental step forward in the quest for the nature of dark matter.

In the 1970s, astronomers Vera Rubin and Kent Ford discovered dark matter accidentally. They were looking at spiral galaxies and noticed that stars far from the galactic centers, in the sparsely populated outer regions, were moving just as fast as those closer in. This was unexpected. The visible mass of a galaxy doesn’t have enough gravity to keep such rapidly moving stars in those sorts of orbits. Thus the astronomers were faced with a startling conclusion. There is more to galaxies than meets the eye, a tremendous amount of unseen matter in the outer regions of galaxies where visible stars are relatively few.

That was a powerful step forward in our understanding of the universe, and, since then, astronomers have gotten very good at inferring the existence and properties of dark matter from its gravitational effects on visible matter and radiation. Indeed, the large-scale structure of the universe itself is thought to be driven in large part by dark matter. However, no one has yet detected dark matter directly. We can only infer that it exists, not know that it does.

What’s more, it been very difficult to establish that dark matter exists not only on the outskirts of the Milky Way, but also in the inner part of the galaxy, where our Earth and sun reside. That’s because our measurements – the same sorts of measurements used to find dark matter in the first place – have not been precise enough to reveal dark matter from our own position in the Milky Way. Miguel Pato at the Department of Physics at Stockholm University said:

In our new study, we obtained for the first time a direct observational proof of the presence of dark matter in the innermost part of the Milky Way.

We have created the most complete compilation so far of published measurements of the motion of gas and stars in the Milky Way, and compared the measured rotation speed with that expected under the assumption that only luminous matter exists in the galaxy.

The observed rotation cannot be explained unless large amounts of dark matter exist around us, and between us and the galactic center.

Our method will allow for upcoming astronomical observations to measure the distribution of dark matter in our galaxy with unprecedented precision. This will permit to refine our understanding of the structure and evolution of our galaxy, and it will trigger more robust predictions for the many experiments worldwide that search for dark matter particles. The study therefore constitutes a fundamental step forward in the quest for the nature of dark matter.

Bottom line: Astronomers in Stockholm say their new technique has revealed dark matter in the inner Milky Way galaxy, including the area in which our sun and Earth reside.

Via Science Daily

from EarthSky http://ift.tt/16UgsJs

A very cool NASA video celebrating 5 years of looking at the sun from space

What NASA says:

February 11, 2015 marks five years in space for NASA’s Solar Dynamics Observatory, which provides incredibly detailed images of the whole sun 24 hours a day. Capturing an image more than once per second, SDO has provided an unprecedentedly clear picture of how massive explosions on the sun grow and erupt ever since its launch on Feb. 11, 2010. The imagery is also captivating, allowing one to watch the constant ballet of solar material through the sun’s atmosphere, the corona.

In honor of SDO’s fifth anniversary, NASA has released a video showcasing highlights from the last five years of sun watching. Watch the movie to see giant clouds of solar material hurled out into space, the dance of giant loops hovering in the corona, and huge sunspots growing and shrinking on the sun’s surface.

The imagery is an example of the kind of data that SDO provides to scientists. By watching the sun in different wavelengths – and therefore different temperatures – scientists can watch how material courses through the corona, which holds clues to what causes eruptions on the sun, what heats the sun’s atmosphere up to 1,000 times hotter than its surface, and why the sun’s magnetic fields are constantly on the move.

Five years into its mission, SDO continues to send back tantalizing imagery to incite scientists’ curiosity. For example, in late 2014, SDO captured imagery of the largest sun spots seen since 1995 as well as a torrent of intense solar flares. Solar flares are bursts of light, energy and X-rays. They can occur by themselves or can be accompanied by what’s called a coronal mass ejection, or CME, in which a giant cloud of solar material erupts off the sun, achieves escape velocity and heads off into space. In this case, the sun produced only flares and no CMEs, which, while not unheard of, is somewhat unusual for flares of that size. Scientists are looking at that data now to see if they can determine what circumstances might have led to flares eruptions alone.

Goddard built, operates and manages the SDO spacecraft for NASA’s Science Mission Directorate in Washington, D.C. SDO is the first mission of NASA’s Living with a Star Program. The program’s goal is to develop the scientific understanding necessary to address those aspects of the sun-Earth system that directly affect our lives and society.

from The Big Science Blog http://ift.tt/1zX8byL

What NASA says:

February 11, 2015 marks five years in space for NASA’s Solar Dynamics Observatory, which provides incredibly detailed images of the whole sun 24 hours a day. Capturing an image more than once per second, SDO has provided an unprecedentedly clear picture of how massive explosions on the sun grow and erupt ever since its launch on Feb. 11, 2010. The imagery is also captivating, allowing one to watch the constant ballet of solar material through the sun’s atmosphere, the corona.

In honor of SDO’s fifth anniversary, NASA has released a video showcasing highlights from the last five years of sun watching. Watch the movie to see giant clouds of solar material hurled out into space, the dance of giant loops hovering in the corona, and huge sunspots growing and shrinking on the sun’s surface.

The imagery is an example of the kind of data that SDO provides to scientists. By watching the sun in different wavelengths – and therefore different temperatures – scientists can watch how material courses through the corona, which holds clues to what causes eruptions on the sun, what heats the sun’s atmosphere up to 1,000 times hotter than its surface, and why the sun’s magnetic fields are constantly on the move.

Five years into its mission, SDO continues to send back tantalizing imagery to incite scientists’ curiosity. For example, in late 2014, SDO captured imagery of the largest sun spots seen since 1995 as well as a torrent of intense solar flares. Solar flares are bursts of light, energy and X-rays. They can occur by themselves or can be accompanied by what’s called a coronal mass ejection, or CME, in which a giant cloud of solar material erupts off the sun, achieves escape velocity and heads off into space. In this case, the sun produced only flares and no CMEs, which, while not unheard of, is somewhat unusual for flares of that size. Scientists are looking at that data now to see if they can determine what circumstances might have led to flares eruptions alone.

Goddard built, operates and manages the SDO spacecraft for NASA’s Science Mission Directorate in Washington, D.C. SDO is the first mission of NASA’s Living with a Star Program. The program’s goal is to develop the scientific understanding necessary to address those aspects of the sun-Earth system that directly affect our lives and society.

from The Big Science Blog http://ift.tt/1zX8byL

Amazonian study quantifies key role of grandparents in family nutrition

A Tsimane mother (left) of twin daughters and a young boy gets assistance from her own mother (right) in their care.



By Carol Clark



Anyone who has ever loved a grandmother or grandfather knows the nurturing role that grandparents can play. A study of indigenous people in Amazonia, who survive on food they hunt, forage or cultivate, quantifies the evolutionary benefit of that role. The results show that grandparents contribute a biologically significant amount of food calories to their extended families.



Proceedings of the Royal Society B published the results of the study of the Tsimane people of Bolivia, led by Paul Hooper, an anthropologist at Emory University.



“We quantified the net flow of calories among individuals in an environment where access to food is limited and depends on people generating it themselves,” Hooper says. “The results support the theory that grandparents are key to our relatively long childhood and long lifespan, which are a big part of what makes us human. Their efforts have likely been underwriting human society for hundreds of thousands of years.”



The study found that fathers and mothers contributed the most net calories to their nuclear family unit, followed by grandfathers and grandmothers, then uncles, aunts and children above the age of 12.



Relative to other primates and mammals, humans mature later and live longer, including many post-reproductive years. Evolutionary theories have proposed that intergenerational resource transfers bolster these distinctive features of human life history. This new study is the first to fully unite the production of resources over a lifetime with inclusive fitness theory, and then test the unified model in an empirical analysis.

Members of a family work together to prepare a meal from ingredients they have gathered from their environment. "About 95 percent of their food comes directly from their own labor," Hooper says.



“Our data give a clear picture of how the life history of our species is supported by high surplus food production in older age and the redistribution of that surplus to younger kin,” Hooper says. “Beyond showing that food resources flowed from older to younger generations, we were able to predict how much each person gave to each other, based on their relative productivity and the closeness of their relationship.”



Hooper led the research as a graduate student at the University of New Mexico and then as a post-doctoral fellow at the Santa Fe Institute. His co-authors include anthropologists Hillard Kaplan, Michael Gurven and Jeffrey Winking.



The researchers spent five years collecting data on 239 Tsimane families from eight villages. The Tsimane (pronounced Chee-mahn-AY in Spanish) live in small, isolated communities along the Maniqui River in the Amazonian rainforest that are only accessible by canoe or logging roads. These communities speak their own language, lack modern sanitation and electricity, and have access to few consumer goods beyond axes, machetes and other basic supplies.



The Tsimane clear small patches of forest to cultivate cassava, plantains, rice and corn. They also forage plants and fish and hunt meat in the form of peccary, deer, tapirs, monkeys and capybara (a large rodent). “About 95 percent of their food comes directly from their own labor,” Hooper says. “It’s an isolated, small-scale society that gives us an idea of the way humans lived before modern industrialization.”



The study broke down average caloric intake by various age groups of the participants, ranging from about 700 calories per day for an infant to more than 3,000 calories per day for adults. They also quantified the amount of calories each family member contributed to the household, from a bushel of plantains or a kilo of rice to the meat of a butchered deer.

The evolutionary value of grandfathers has been largely overlooked, Hooper says.



The results showed that Tsimane parents and grandparents provide net economic contributions to kin into the seventh decade of life. Households with higher food productivity and fewer dependents provided net transfers to closely related, usually younger, households with lower productivity and more dependents.



The value of grandmothers had been highlighted in previous studies linking them to improved outcomes for grandchildren. The contribution of grandfathers, however, has been largely overlooked, Hooper says.



While food is a limiting resource among the Tsimane, Hooper notes that in order to conduct a similar study in an industrialized society the focus should shift from food to money and time.



“Whether you’re a hunter-gather or an accountant, you’re good at what you do because someone supported you while you developed and learned skills,” Hooper says. “The economics of learning are what makes grandparents so important to humans compared to other primates.”



In modern, fast-paced societies, undergoing rapid technological change, the value of grandparents may be overlooked, he adds. “When technology moves at a fast rate, it can shift the age of competence to younger ages. We’re in danger of not recognizing the wisdom of older people, accumulated over lifetimes.”



Hooper, who lost his last grandparent, his maternal grandmother, a few weeks before the study was published, says she influenced his career choice. “She completed a graduate degree in biology during the 1930s, so she was way ahead of her time,” he says. “I learned about Darwin and evolution from her. She taught me the importance of biology for understanding ourselves and our place in the universe.”



Photos courtesy of Paul Hooper



Related:

Dawn of agriculture took toll on health

Putting teeth into the Barker hypothesis



from eScienceCommons http://ift.tt/1Ansl6P

A Tsimane mother (left) of twin daughters and a young boy gets assistance from her own mother (right) in their care.



By Carol Clark



Anyone who has ever loved a grandmother or grandfather knows the nurturing role that grandparents can play. A study of indigenous people in Amazonia, who survive on food they hunt, forage or cultivate, quantifies the evolutionary benefit of that role. The results show that grandparents contribute a biologically significant amount of food calories to their extended families.



Proceedings of the Royal Society B published the results of the study of the Tsimane people of Bolivia, led by Paul Hooper, an anthropologist at Emory University.



“We quantified the net flow of calories among individuals in an environment where access to food is limited and depends on people generating it themselves,” Hooper says. “The results support the theory that grandparents are key to our relatively long childhood and long lifespan, which are a big part of what makes us human. Their efforts have likely been underwriting human society for hundreds of thousands of years.”



The study found that fathers and mothers contributed the most net calories to their nuclear family unit, followed by grandfathers and grandmothers, then uncles, aunts and children above the age of 12.



Relative to other primates and mammals, humans mature later and live longer, including many post-reproductive years. Evolutionary theories have proposed that intergenerational resource transfers bolster these distinctive features of human life history. This new study is the first to fully unite the production of resources over a lifetime with inclusive fitness theory, and then test the unified model in an empirical analysis.

Members of a family work together to prepare a meal from ingredients they have gathered from their environment. "About 95 percent of their food comes directly from their own labor," Hooper says.



“Our data give a clear picture of how the life history of our species is supported by high surplus food production in older age and the redistribution of that surplus to younger kin,” Hooper says. “Beyond showing that food resources flowed from older to younger generations, we were able to predict how much each person gave to each other, based on their relative productivity and the closeness of their relationship.”



Hooper led the research as a graduate student at the University of New Mexico and then as a post-doctoral fellow at the Santa Fe Institute. His co-authors include anthropologists Hillard Kaplan, Michael Gurven and Jeffrey Winking.



The researchers spent five years collecting data on 239 Tsimane families from eight villages. The Tsimane (pronounced Chee-mahn-AY in Spanish) live in small, isolated communities along the Maniqui River in the Amazonian rainforest that are only accessible by canoe or logging roads. These communities speak their own language, lack modern sanitation and electricity, and have access to few consumer goods beyond axes, machetes and other basic supplies.



The Tsimane clear small patches of forest to cultivate cassava, plantains, rice and corn. They also forage plants and fish and hunt meat in the form of peccary, deer, tapirs, monkeys and capybara (a large rodent). “About 95 percent of their food comes directly from their own labor,” Hooper says. “It’s an isolated, small-scale society that gives us an idea of the way humans lived before modern industrialization.”



The study broke down average caloric intake by various age groups of the participants, ranging from about 700 calories per day for an infant to more than 3,000 calories per day for adults. They also quantified the amount of calories each family member contributed to the household, from a bushel of plantains or a kilo of rice to the meat of a butchered deer.

The evolutionary value of grandfathers has been largely overlooked, Hooper says.



The results showed that Tsimane parents and grandparents provide net economic contributions to kin into the seventh decade of life. Households with higher food productivity and fewer dependents provided net transfers to closely related, usually younger, households with lower productivity and more dependents.



The value of grandmothers had been highlighted in previous studies linking them to improved outcomes for grandchildren. The contribution of grandfathers, however, has been largely overlooked, Hooper says.



While food is a limiting resource among the Tsimane, Hooper notes that in order to conduct a similar study in an industrialized society the focus should shift from food to money and time.



“Whether you’re a hunter-gather or an accountant, you’re good at what you do because someone supported you while you developed and learned skills,” Hooper says. “The economics of learning are what makes grandparents so important to humans compared to other primates.”



In modern, fast-paced societies, undergoing rapid technological change, the value of grandparents may be overlooked, he adds. “When technology moves at a fast rate, it can shift the age of competence to younger ages. We’re in danger of not recognizing the wisdom of older people, accumulated over lifetimes.”



Hooper, who lost his last grandparent, his maternal grandmother, a few weeks before the study was published, says she influenced his career choice. “She completed a graduate degree in biology during the 1930s, so she was way ahead of her time,” he says. “I learned about Darwin and evolution from her. She taught me the importance of biology for understanding ourselves and our place in the universe.”



Photos courtesy of Paul Hooper



Related:

Dawn of agriculture took toll on health

Putting teeth into the Barker hypothesis



from eScienceCommons http://ift.tt/1Ansl6P

Out of the Earth, Out of the Blue [Page 3.14]

Greg Laden reports on a hominid fossil “recovered from the seabed near Taiwan” which reveals new levels of dental diversity among proto-humans and may qualify as a new species. Greg says the specimen known as Penghu “is yet another indicator that multiple different hominids lived on the Earth at the same time after the rise of Homo erectus.” But why was it located underwater? In another example of what lies beneath, Dr. Dolittle marvels at “an unexpected find and very exciting moment for researchers;” the discovery of small fish and invertebrates thriving below 740 meters of ice near the coast of Antarctica. Exactly how these animals survive in the stark ecosystem has yet to be determined. Meanwhile, on Uncertain Principles, Chad Orzel reflects on the history of surprising physics discoveries. He provides as an example the discovery of the muon in 1936, a subatomic particle that no one was even looking for. Chad writes, “The eminently quotable I.I. Rabi famously responded to the news by asking ‘Who ordered that?'” No one, but we’ll take it.

from ScienceBlogs http://ift.tt/1zMosYA

Greg Laden reports on a hominid fossil “recovered from the seabed near Taiwan” which reveals new levels of dental diversity among proto-humans and may qualify as a new species. Greg says the specimen known as Penghu “is yet another indicator that multiple different hominids lived on the Earth at the same time after the rise of Homo erectus.” But why was it located underwater? In another example of what lies beneath, Dr. Dolittle marvels at “an unexpected find and very exciting moment for researchers;” the discovery of small fish and invertebrates thriving below 740 meters of ice near the coast of Antarctica. Exactly how these animals survive in the stark ecosystem has yet to be determined. Meanwhile, on Uncertain Principles, Chad Orzel reflects on the history of surprising physics discoveries. He provides as an example the discovery of the muon in 1936, a subatomic particle that no one was even looking for. Chad writes, “The eminently quotable I.I. Rabi famously responded to the news by asking ‘Who ordered that?'” No one, but we’ll take it.

from ScienceBlogs http://ift.tt/1zMosYA

How big are the biggest monster stars?

How big can stars get? And how do these monster stars get so big? But when speaking of bigness among stars, you have to define your terms. The heaviest star is thought to be R136a1. It’s 265 times more massive than our sun – nearly twice as massive as what astronomers thought was possible. It’s the most massive star known at this time (February 2015), and it’s also the most luminous star known at more than 7 million times the luminosity of our sun. But there are more ways than one to measure stars’ bigness. In terms of sheer physical size, another exceedingly large star is UY Scuti. It’s only 30 times the sun’s mass, but has a radius more than 1,700 greater than the sun. Follow the links below to learn more about these monster stars.

R136a1 is the heaviest star, with 265 times the sun’s mass

UY Scuti is just plain big, with a radius 1,700 times that of our sun

Left to right: a red dwarf, the Sun, a blue dwarf, and R136a1. R136a1 is not the largest known star in terms of radius or volume, only in mass and luminosity. Image via Wikipedia.

R136a1 is the heaviest star, with 265 times the sun’s mass. R136a1 is what’s known as a Wolf–Rayet star. Its surface temperature is over 100,000 degrees F.

For decades, theories have suggested that no stars can be born by ordinary processes above 150 solar masses. So how did R136a1 and stars like it grow so large? And why aren’t monster stars scattered throughout space?

One idea is that supermassive stars like R136a1 form through mergers of multiple stars. In 2012, astronomers at the University of Bonn suggested the the ultramassive stars in the Large Magellanic Cloud – such as R136a1 – were created lighter stars in tight double-star systems merged.

Still, double-star systems are common. So why don’t we see more super-sized stars? The astronomers in Bonn say it’s because these stars formed under special conditions – in a densely packed star cluster. In a closely packed star cluster, double-stars are more likely to encounter each other and merge.

But if these ultramassive stars form in this way, why don’t we see more of them? After all, multiple star systems are common throughout space, while monster stars are few and far between.

The answer may be that monster stars don’t live very long. They evolve very quickly in contrast to less massive stars like our sun. They end their lives in violent supernova explosions.

List of most massive stars

UY Scuti size comparison to the sun. Image by Philip Park via Jillian Scudder

UY Scuti is just plain big, with a radius 1,700 times that of our sun. Located some 9,500 light-years away, this star is the leading candidate for being the largest known star. In February 2015, astrophysicist Jillian Scudder of University of Sussex posted a story at The Conversation about the star UY Scuti. As she pointed out:

Mass and physical size don’t always correlate for stars, particularly for giant stars.

UY Scuti is thought to have a mass only slightly more than 30 times the mass of our sun. But its radius is thought to be something like 1,700 times greater than the radius of the sun. That would make this star is nearly eight astronomical units across – that’s eight times the distance between the Earth and sun. In other words, this single star is so large that its outer surface would extend far beyond the orbit of the planet Jupiter (which lies about five times farther from the sun than Earth). Scudder wrote:

This star is one of a class of stars that varies in brightness because it varies in size, so this number is also likely to change over time. The margin of error on this measurement is about 192 solar radii. This uncertainty is why I used ‘possibly one of the largest stars’ in my description of UY Scuti. If it is smaller by 192 solar radii, there are a few other candidates that would beat UY Scuti.

Who are those other candidates? They would include NML Cygni, whose estimated distance is about 5,300 light-years way and whose radius is thought to be 1,650 times greater than that of our sun. A recent study of this star suggested that it’s an unusual hypergiant star cocooned within a nebula and severely obscured by dust. Thus we don’t know its size exactly, and the true range might between 1,642 to 2,775 solar radii. The upper part of the range would make it larger than UY Scuti.

Another hypergiant star is WOH G64, also in the Large Magellanic Cloud, and thus located at a distance of some 168,000 light years from Earth. At an estimated 1,540 times the sun’s radius, this star is thought to be the largest star in the Large Magellanic Cloud, in terms of sheer physical size. And, again, we’re talking size here, not mass. This star is thought to have only 25 times the sun’s mass.

So you can see that there are extremely heavy stars … and then there are simply gigantic stars. What makes a star big might be its mass (like R136a1) or its physical size (like UY Scuti and the two other stars mentioned here). Either way, it’s fun to imagine what it would be like to have one of these stars relatively close to us in space … say, the distance to the nearest star system, Alpha Centauri, only four light-years away.

At that distance, any of these stars would blaze in our night sky!

Bottom line: Astronomers have said for decades that no star can be born by ordinary processes with more than 150 times our sun’s mass. And yet astronomers have identified more massive stars. The most massive star known is R136a1, in the Large Magellanic Cloud. It’s thought to be about 265 times more massive than our sun. Stars are also considered big if their sheer physical size is big. Some stars are so large that, if they replaced the sun in our solar system, their outer surface would extend beyond Jupiter.

from EarthSky http://ift.tt/16UpG8K

How big can stars get? And how do these monster stars get so big? But when speaking of bigness among stars, you have to define your terms. The heaviest star is thought to be R136a1. It’s 265 times more massive than our sun – nearly twice as massive as what astronomers thought was possible. It’s the most massive star known at this time (February 2015), and it’s also the most luminous star known at more than 7 million times the luminosity of our sun. But there are more ways than one to measure stars’ bigness. In terms of sheer physical size, another exceedingly large star is UY Scuti. It’s only 30 times the sun’s mass, but has a radius more than 1,700 greater than the sun. Follow the links below to learn more about these monster stars.

R136a1 is the heaviest star, with 265 times the sun’s mass

UY Scuti is just plain big, with a radius 1,700 times that of our sun

Left to right: a red dwarf, the Sun, a blue dwarf, and R136a1. R136a1 is not the largest known star in terms of radius or volume, only in mass and luminosity. Image via Wikipedia.

R136a1 is the heaviest star, with 265 times the sun’s mass. R136a1 is what’s known as a Wolf–Rayet star. Its surface temperature is over 100,000 degrees F.

For decades, theories have suggested that no stars can be born by ordinary processes above 150 solar masses. So how did R136a1 and stars like it grow so large? And why aren’t monster stars scattered throughout space?

One idea is that supermassive stars like R136a1 form through mergers of multiple stars. In 2012, astronomers at the University of Bonn suggested the the ultramassive stars in the Large Magellanic Cloud – such as R136a1 – were created lighter stars in tight double-star systems merged.

Still, double-star systems are common. So why don’t we see more super-sized stars? The astronomers in Bonn say it’s because these stars formed under special conditions – in a densely packed star cluster. In a closely packed star cluster, double-stars are more likely to encounter each other and merge.

But if these ultramassive stars form in this way, why don’t we see more of them? After all, multiple star systems are common throughout space, while monster stars are few and far between.

The answer may be that monster stars don’t live very long. They evolve very quickly in contrast to less massive stars like our sun. They end their lives in violent supernova explosions.

List of most massive stars

UY Scuti size comparison to the sun. Image by Philip Park via Jillian Scudder

UY Scuti is just plain big, with a radius 1,700 times that of our sun. Located some 9,500 light-years away, this star is the leading candidate for being the largest known star. In February 2015, astrophysicist Jillian Scudder of University of Sussex posted a story at The Conversation about the star UY Scuti. As she pointed out:

Mass and physical size don’t always correlate for stars, particularly for giant stars.

UY Scuti is thought to have a mass only slightly more than 30 times the mass of our sun. But its radius is thought to be something like 1,700 times greater than the radius of the sun. That would make this star is nearly eight astronomical units across – that’s eight times the distance between the Earth and sun. In other words, this single star is so large that its outer surface would extend far beyond the orbit of the planet Jupiter (which lies about five times farther from the sun than Earth). Scudder wrote:

This star is one of a class of stars that varies in brightness because it varies in size, so this number is also likely to change over time. The margin of error on this measurement is about 192 solar radii. This uncertainty is why I used ‘possibly one of the largest stars’ in my description of UY Scuti. If it is smaller by 192 solar radii, there are a few other candidates that would beat UY Scuti.

Who are those other candidates? They would include NML Cygni, whose estimated distance is about 5,300 light-years way and whose radius is thought to be 1,650 times greater than that of our sun. A recent study of this star suggested that it’s an unusual hypergiant star cocooned within a nebula and severely obscured by dust. Thus we don’t know its size exactly, and the true range might between 1,642 to 2,775 solar radii. The upper part of the range would make it larger than UY Scuti.

Another hypergiant star is WOH G64, also in the Large Magellanic Cloud, and thus located at a distance of some 168,000 light years from Earth. At an estimated 1,540 times the sun’s radius, this star is thought to be the largest star in the Large Magellanic Cloud, in terms of sheer physical size. And, again, we’re talking size here, not mass. This star is thought to have only 25 times the sun’s mass.

So you can see that there are extremely heavy stars … and then there are simply gigantic stars. What makes a star big might be its mass (like R136a1) or its physical size (like UY Scuti and the two other stars mentioned here). Either way, it’s fun to imagine what it would be like to have one of these stars relatively close to us in space … say, the distance to the nearest star system, Alpha Centauri, only four light-years away.

At that distance, any of these stars would blaze in our night sky!

Bottom line: Astronomers have said for decades that no star can be born by ordinary processes with more than 150 times our sun’s mass. And yet astronomers have identified more massive stars. The most massive star known is R136a1, in the Large Magellanic Cloud. It’s thought to be about 265 times more massive than our sun. Stars are also considered big if their sheer physical size is big. Some stars are so large that, if they replaced the sun in our solar system, their outer surface would extend beyond Jupiter.

from EarthSky http://ift.tt/16UpG8K

2015 has three Friday the 13s. What are the odds?

Scared of Friday the 13th? An irrational fear of this date is called friggatriskaidekaphobia (Frigga is the Norse goddess for whom Friday is named). Image via Kelli Marshall

February 13, 2015 is a Friday. And that’s just the beginning of this year’s epic Friday the 13th trilogy. We’ll have a Friday the 13th in March, too – exactly four weeks after February’s Friday the 13th! Then we’ll have a Friday the 13th in November – exactly 39 weeks (3 x 13 weeks) after February’s Friday the 13th!

Not that we at EarthSky suffer from friggatriskaidekaphobia – an irrational fear of Friday the 13th – but, gosh darn, it’s Friday the 13th three times over in 2015. Follow the links below to learn more about why some people fear this day and about 2015’s three Friday the 13ths.

Scary coincidence or super unlucky?

In 2015, blame Thursday

The February-March-November Friday the 13th trilogy repeats …

The rhyme and reason of the Friday the 13th cycle

Friday-the-13th-year repetitions within 28-year cycle

Can three Friday the 13ths occur in a leap year?

The Friday the 13th slasher-movie franchise helped keep this day maintain its notoriety. Image via Wikimedia Commons

Gioachino Rossini, a 19th century Italian composer. Folklorists say there's no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards' 1869 biography of Rossini.

Scary coincidence or super unlucky? Neither. It’s just a quirk of our calendar, as you’ll see if you keep reading.

The fact is that, according to folklorists, there’s no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards’ 1869 biography of Gioachino Rossini. His portrait is on this page. He doesn’t look scary.

Friday has always gotten a bad rap. In the Middle Ages, people would not marry – or set out on a journey – on a Friday.

There are also some links between Christianity and an ill association with either Fridays or the number 13. Jesus was said to be crucified on a Friday. Seating 13 people at a table was seen as bad luck because Judas Iscariot, the disciple who betrayed Jesus, is said to have been the 13th guest at the Last Supper. Meanwhile, our word for Friday comes from Frigga, an ancient Scandinavian fertility and love goddess. Christians called Frigga a witch and Friday the witches’ Sabbath.

In modern times, the slasher-movie franchise Friday the 13th has helped keep friggatriskaidekaphobia alive.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

In 2015, blame Thursday. The year 2015 started on a Thursday. Whenever a common year of 365 days starts on a Thursday, it’s inevitable that the months of February, March and November will start on a Sunday. And any month starting on a Sunday always has a Friday the 13th.

Of course, February has exactly four weeks in a non-leap year. So, for that reason, the days of the week have to match up with the same dates in both February and March during any common year. In any year, the days of the week always fall on the same dates in both March and November. In short, because the year 2015 started on a Thursday, that means February, March and November all have to start on a Sunday and all must have a Friday the 13th.

The February-March-November Friday the 13th trilogy repeats … More often than you might imagine! The last February-March-November Friday the 13th year happened six years ago, in 2009, for the first time in the 21st century (2001-2100). It will next happen eleven years from now, in 2026. After that, the following February-March-November Friday the 13th year will happen eleven years after 2026, in the year 2037.

A grand total of eleven February-March-November Friday the 13th years takes place in the 21st century:

2009, 2015, 2026, 2037, 2043, 2054, 2065, 2071, 2082, 2093 and 2099.

Calendar for 2015

Calendar for 2015, courtesy of timeanddate.com

The rhyme and reason of the Friday the 13th cycle. Yes, it does make sense. Within the 21st century (2001-2100), note that the February-March-November Friday the 13th years repeat in 28-year cycles (going crosswise):

2009, 2037, 2065, 2093

2015, 2043, 2071, 2099

2026, 2054, 2082

Because the Gregorian calendar suppresses the leap year in 2100, the cycle is perturbed, meaning that all eleven February-March-November Friday the 13th years in the 22nd century (2101-2200) come four years earlier than in the 21st century:

2105, 2111, 2122, 2133, 2139, 2150, 2161, 2167, 2178, 2189 and 2195.

However, within the 22nd century (2101-2200), these Friday the 13th years also repeat in cycles of 28 years.

2105, 2133, 2161, 2189

2111, 2139, 2167, 2195

2122, 2150, 2178

Friday-the-13th-year repetitions within 28-year cycle. Some of you, who might not yet be dazed by calendar numerology, may wonder if some formula governs how a given Friday the 13th year repeats within the 28-year cycle. The answer is a definite yes. Keep in mind that this particular February-March-November Friday the 13th year can only happen in a common year of 365 days, and when January 1 falls on a Thursday.

Therefore, if this threefold Friday the 13th year comes one year after a leap year, the days again match up with the dates in 6, 17 and 28 years afterward. Take the year 2009, for example, which comes one year after a leap year:

2009, 2015, 2026, 2037

However, if this triple Friday the 13th year falls two years after a leap year, the days and dates realign in 11, 17 and 28 years. Take the year 2026, which takes place two years after a leap year:

2026, 2037, 2043, 2054

Finally, if this trio of Friday the 13ths happens three years after a leap year, the days and dates coincide in 11, 22 and 28 years. The year 2015 happens three years after a leap year:

2015, 2026, 2037, 2043

Can three Friday the 13ths occur in a leap year?

Yes, a leap year can harbor three Friday the 13ths (January 13 – April 13 – July 13) if the leap year starts on a Sunday, which last happened in 2012. However, given that this particular Friday the 13th year happens in a leap year, and a leap year only, it recurs only in periods of 28 years. So the last January-April-July Friday the 13th year happened in 1984, and will next happen in 2040.

If a common year starts on a Thursday, there are three Friday the 13ths; and if a leap year begins on a Sunday, there are three Friday the 13ths. These are the two scenarios whereby three Friday the 13ths can occur in single calendar year.

Bottom line: Scary coincidence or super unlucky? Neither. Here’s the story behind why 2015 has three Friday the 13ths.

2012 has three Friday the 13ths. What are the odds?

from EarthSky http://ift.tt/16UjayE

Scared of Friday the 13th? An irrational fear of this date is called friggatriskaidekaphobia (Frigga is the Norse goddess for whom Friday is named). Image via Kelli Marshall

February 13, 2015 is a Friday. And that’s just the beginning of this year’s epic Friday the 13th trilogy. We’ll have a Friday the 13th in March, too – exactly four weeks after February’s Friday the 13th! Then we’ll have a Friday the 13th in November – exactly 39 weeks (3 x 13 weeks) after February’s Friday the 13th!

Not that we at EarthSky suffer from friggatriskaidekaphobia – an irrational fear of Friday the 13th – but, gosh darn, it’s Friday the 13th three times over in 2015. Follow the links below to learn more about why some people fear this day and about 2015’s three Friday the 13ths.

Scary coincidence or super unlucky?

In 2015, blame Thursday

The February-March-November Friday the 13th trilogy repeats …

The rhyme and reason of the Friday the 13th cycle

Friday-the-13th-year repetitions within 28-year cycle

Can three Friday the 13ths occur in a leap year?

The Friday the 13th slasher-movie franchise helped keep this day maintain its notoriety. Image via Wikimedia Commons

Gioachino Rossini, a 19th century Italian composer. Folklorists say there's no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards' 1869 biography of Rossini.

Scary coincidence or super unlucky? Neither. It’s just a quirk of our calendar, as you’ll see if you keep reading.

The fact is that, according to folklorists, there’s no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards’ 1869 biography of Gioachino Rossini. His portrait is on this page. He doesn’t look scary.

Friday has always gotten a bad rap. In the Middle Ages, people would not marry – or set out on a journey – on a Friday.

There are also some links between Christianity and an ill association with either Fridays or the number 13. Jesus was said to be crucified on a Friday. Seating 13 people at a table was seen as bad luck because Judas Iscariot, the disciple who betrayed Jesus, is said to have been the 13th guest at the Last Supper. Meanwhile, our word for Friday comes from Frigga, an ancient Scandinavian fertility and love goddess. Christians called Frigga a witch and Friday the witches’ Sabbath.

In modern times, the slasher-movie franchise Friday the 13th has helped keep friggatriskaidekaphobia alive.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

In 2015, blame Thursday. The year 2015 started on a Thursday. Whenever a common year of 365 days starts on a Thursday, it’s inevitable that the months of February, March and November will start on a Sunday. And any month starting on a Sunday always has a Friday the 13th.

Of course, February has exactly four weeks in a non-leap year. So, for that reason, the days of the week have to match up with the same dates in both February and March during any common year. In any year, the days of the week always fall on the same dates in both March and November. In short, because the year 2015 started on a Thursday, that means February, March and November all have to start on a Sunday and all must have a Friday the 13th.

The February-March-November Friday the 13th trilogy repeats … More often than you might imagine! The last February-March-November Friday the 13th year happened six years ago, in 2009, for the first time in the 21st century (2001-2100). It will next happen eleven years from now, in 2026. After that, the following February-March-November Friday the 13th year will happen eleven years after 2026, in the year 2037.

A grand total of eleven February-March-November Friday the 13th years takes place in the 21st century:

2009, 2015, 2026, 2037, 2043, 2054, 2065, 2071, 2082, 2093 and 2099.

Calendar for 2015

Calendar for 2015, courtesy of timeanddate.com

The rhyme and reason of the Friday the 13th cycle. Yes, it does make sense. Within the 21st century (2001-2100), note that the February-March-November Friday the 13th years repeat in 28-year cycles (going crosswise):

2009, 2037, 2065, 2093

2015, 2043, 2071, 2099

2026, 2054, 2082

Because the Gregorian calendar suppresses the leap year in 2100, the cycle is perturbed, meaning that all eleven February-March-November Friday the 13th years in the 22nd century (2101-2200) come four years earlier than in the 21st century:

2105, 2111, 2122, 2133, 2139, 2150, 2161, 2167, 2178, 2189 and 2195.

However, within the 22nd century (2101-2200), these Friday the 13th years also repeat in cycles of 28 years.

2105, 2133, 2161, 2189

2111, 2139, 2167, 2195

2122, 2150, 2178

Friday-the-13th-year repetitions within 28-year cycle. Some of you, who might not yet be dazed by calendar numerology, may wonder if some formula governs how a given Friday the 13th year repeats within the 28-year cycle. The answer is a definite yes. Keep in mind that this particular February-March-November Friday the 13th year can only happen in a common year of 365 days, and when January 1 falls on a Thursday.

Therefore, if this threefold Friday the 13th year comes one year after a leap year, the days again match up with the dates in 6, 17 and 28 years afterward. Take the year 2009, for example, which comes one year after a leap year:

2009, 2015, 2026, 2037

However, if this triple Friday the 13th year falls two years after a leap year, the days and dates realign in 11, 17 and 28 years. Take the year 2026, which takes place two years after a leap year:

2026, 2037, 2043, 2054

Finally, if this trio of Friday the 13ths happens three years after a leap year, the days and dates coincide in 11, 22 and 28 years. The year 2015 happens three years after a leap year:

2015, 2026, 2037, 2043

Can three Friday the 13ths occur in a leap year?

Yes, a leap year can harbor three Friday the 13ths (January 13 – April 13 – July 13) if the leap year starts on a Sunday, which last happened in 2012. However, given that this particular Friday the 13th year happens in a leap year, and a leap year only, it recurs only in periods of 28 years. So the last January-April-July Friday the 13th year happened in 1984, and will next happen in 2040.

If a common year starts on a Thursday, there are three Friday the 13ths; and if a leap year begins on a Sunday, there are three Friday the 13ths. These are the two scenarios whereby three Friday the 13ths can occur in single calendar year.

Bottom line: Scary coincidence or super unlucky? Neither. Here’s the story behind why 2015 has three Friday the 13ths.

2012 has three Friday the 13ths. What are the odds?

from EarthSky http://ift.tt/16UjayE

Contraception and Colorado’s dropping teen pregnancy and abortion rates [The Pump Handle]

Last week, Vox’s German Lopez highlighted a recent study that demonstrates how improving access to the most effective contraceptives can slash the rates of unintended pregnancies and abortions among teens. After the Colorado Family Planning Initiative (CFPI) started providing free IUDs and implants to low-income women at family planning clinics, the teen birth rate and abortion rate dropped sharply. Lopez notes that the teen birth rate has been declining nationwide, but Colorado’s has dropped more quickly: “Between 2008 and 2012, the state went from the 29th lowest teen birth rate in the nation to the 19th lowest.”

A study by Sue Ricketts, Greta Klingler, and Renee Schwalberg, published in Perspectives on Sexual and Reproductive Health’s September 2014 issue, describes the project and research findings in greater detail. In 2009, the Colorado Department of Public Health and Environment began using private money from an anonymous foundation to allow Title X family planning clinics to provide long-acting, reversible contraceptive (LARC) methods for free. (Title X centers provide cost-effective family planning and related preventive health services to low-income men and women; Kim wrote about Massachusetts Title X providers last year.) The funding supported purchase of IUDs and implants as well as training for providers and staff and technical assistance. Ricketts and her colleagues explain why in the past LARC methods have not been widely used by adolescents, despite being recommended:

LARC methods—implants and IUDs—have been shown to be effective in reducing rates of unintended pregnancy among adolescents, and their use in this population is endorsed by the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, the Centers for Disease Control and Prevention, and the World Health Organization.[1, 2] Compared with the pill, patch and ring, LARC methods have low failure rates and a reduced likelihood of noncompliant use, which make them particularly suitable for adolescents. Increasing the use of these methods is a recommended strategy to reduce rates of unintended pregnancy.[3] Among all users of Title X–funded family planning clinics in 2011, however, the IUD and implant were used by only 2% of clients younger than 20.[4]

A number of barriers to LARC use among young women and others at high risk of unintended pregnancy have been described. Two barriers are the low level of awareness among consumers and providers of the availability, safety and appropriateness of LARC methods for both parous and nulliparous young women and the time required for counseling about these methods.[5, 6] In addition, high initial costs pose a substantial barrier to greater utilization.[7] In the longitudinal Contraceptive CHOICE Project in St. Louis, 70% of women aged 14–20 chose LARC methods when cost was not a factor.[8] Between 2008 and 2010, the researchers observed declines in the abortion rate, the proportion of abortions that were repeat procedures and the teenage birthrate in the St. Louis area. Furthermore, these rates were lower than those in comparable areas without the study program.[9]

Under the Affordable Care Act, private insurers must cover all FDA-approved forms of contraception, including LARCs, without cost-sharing. States’ Medicaid programs must also cover contraception, but Medicaid eligibility varies substantially from state to state. Uninsured women may still find the costs of LARCs, which can total several hundred dollars, too high. As Ricketts et al note, several states have either waivers or state plan amendments that allow them to use Medicaid funds to offer family-planning services to low-income women, but Colorado does not. (The Kaiser Family Foundation summarizes state waivers and SPAs if you want to see what your state offers.)

Another issue is that young women covered by their parents’ insurance may not want to use that insurance when seeking family-planning services. Title X centers will provide confidential services on a sliding-scale fee basis, so young women can receive the services they need even if they don’t hand over an insurance card. Having such policies means that it can be hard for Title X providers to afford to stock a lot of IUDs and implants, though. Ricketts and colleagues explain that these LARC methods can cost clinics $300-$500 even with special pricing; they report, “Clinics had historically struggled to meet the demand for these two methods within their limited budgets and sliding-fee requirements, and many offered only limited numbers of LARC insertions.”

The bottom line here is that the privately funded CFPI made it possible for Colorado’s Title X providers to greatly improve their clients’ access to LARCs. Before the initiative, only 5% of Title X female clients ages 15-24 used LARC methods; by 2011, that climbed to 19%. Statewide, the birth rate for teens ages 15-19 dropped 26%. Researchers also examined abortion rates for this age group in 37 counties where Title X-funded clinics are located and those in 27 “non-CFPI” counties. They found a 34% drop in abortions among teens ages 15-19 in CFPI counties, and a drop of 29% in non-CFPI counties. Ricketts and her colleagues point out that teens living in non-CFPI counties may well cross county lines to receive family-planning services, so the initiative may have helped lower abortion rates statewide.

Lowering teen birth and abortion rates is a worthwhile public health goal on its own, but state officials with competing funding priorities will also want to know whether funding LARCs for lower-income women might let them reduce spending in other areas. The WIC infant caseload is a leading indicator of low-income births, because researchers can access WIC caseload data well before birth certificate data are finalized, Ricketts et al explain. (WIC, or the Special Supplemental Program for Women, Infants and Children, provides nutrition education and supplemental food for low-income pregnant and postpartum women and for children up to age five who are determined to be at nutritional risk.) Ricketts and her colleagues report:

Continuing a decades-long trend, the number of infants receiving WIC benefits grew steadily in the two years preceding the Colorado Family Planning Initiative, from 24,513 in January 2007 to 26,766 in December 2008 (Figure 2). In 2009, when CFPI began, the number leveled off; it ended the year at 26,862. Subsequently, the number rose to 28,978 in March 2010 and then dropped sharply; by March 2013, it had fallen to 22,407, a level well below that for any month since early 2005. The number of infants served by WIC, which had risen 18% between January 2007 and March 2010, fell 23% in the following three-year period.

Having fewer state residents with incomes low enough to qualify them for various forms of assistance translates to lower expenditures on a variety of programs. In just a few years, Colorado’s experience has demonstrated that investing in LARC accessibility can translate quickly into savings. Benefits to the women receiving LARCs may be harder to quantify, but are substantial. “This initiative has saved Colorado millions of dollars,” said Governor John Hickenlooper in a news release announcing the findings. “But more importantly, it has helped thousands of young Colorado women continue their education, pursue their professional goals and postpone pregnancy until they are ready to start a family.”

I hope these findings (and many others published over the years showing an excellent return on family-planning investments) will prompt other states to increase their investments in family planning for lower-income women. The trend in several states and at the federal level, though, has been for family-planning budgets to fall or remain stagnant despite growing demand. Some of this is likely due to overall budget-cutting pressure, and some to hostility toward women being able to control their reproductive timelines. The evidence is clear, though: improving women’s access to effective contraception pays off financially and for public health.

from ScienceBlogs http://ift.tt/1AYI9hA

Last week, Vox’s German Lopez highlighted a recent study that demonstrates how improving access to the most effective contraceptives can slash the rates of unintended pregnancies and abortions among teens. After the Colorado Family Planning Initiative (CFPI) started providing free IUDs and implants to low-income women at family planning clinics, the teen birth rate and abortion rate dropped sharply. Lopez notes that the teen birth rate has been declining nationwide, but Colorado’s has dropped more quickly: “Between 2008 and 2012, the state went from the 29th lowest teen birth rate in the nation to the 19th lowest.”

A study by Sue Ricketts, Greta Klingler, and Renee Schwalberg, published in Perspectives on Sexual and Reproductive Health’s September 2014 issue, describes the project and research findings in greater detail. In 2009, the Colorado Department of Public Health and Environment began using private money from an anonymous foundation to allow Title X family planning clinics to provide long-acting, reversible contraceptive (LARC) methods for free. (Title X centers provide cost-effective family planning and related preventive health services to low-income men and women; Kim wrote about Massachusetts Title X providers last year.) The funding supported purchase of IUDs and implants as well as training for providers and staff and technical assistance. Ricketts and her colleagues explain why in the past LARC methods have not been widely used by adolescents, despite being recommended:

LARC methods—implants and IUDs—have been shown to be effective in reducing rates of unintended pregnancy among adolescents, and their use in this population is endorsed by the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, the Centers for Disease Control and Prevention, and the World Health Organization.[1, 2] Compared with the pill, patch and ring, LARC methods have low failure rates and a reduced likelihood of noncompliant use, which make them particularly suitable for adolescents. Increasing the use of these methods is a recommended strategy to reduce rates of unintended pregnancy.[3] Among all users of Title X–funded family planning clinics in 2011, however, the IUD and implant were used by only 2% of clients younger than 20.[4]

A number of barriers to LARC use among young women and others at high risk of unintended pregnancy have been described. Two barriers are the low level of awareness among consumers and providers of the availability, safety and appropriateness of LARC methods for both parous and nulliparous young women and the time required for counseling about these methods.[5, 6] In addition, high initial costs pose a substantial barrier to greater utilization.[7] In the longitudinal Contraceptive CHOICE Project in St. Louis, 70% of women aged 14–20 chose LARC methods when cost was not a factor.[8] Between 2008 and 2010, the researchers observed declines in the abortion rate, the proportion of abortions that were repeat procedures and the teenage birthrate in the St. Louis area. Furthermore, these rates were lower than those in comparable areas without the study program.[9]

Under the Affordable Care Act, private insurers must cover all FDA-approved forms of contraception, including LARCs, without cost-sharing. States’ Medicaid programs must also cover contraception, but Medicaid eligibility varies substantially from state to state. Uninsured women may still find the costs of LARCs, which can total several hundred dollars, too high. As Ricketts et al note, several states have either waivers or state plan amendments that allow them to use Medicaid funds to offer family-planning services to low-income women, but Colorado does not. (The Kaiser Family Foundation summarizes state waivers and SPAs if you want to see what your state offers.)

Another issue is that young women covered by their parents’ insurance may not want to use that insurance when seeking family-planning services. Title X centers will provide confidential services on a sliding-scale fee basis, so young women can receive the services they need even if they don’t hand over an insurance card. Having such policies means that it can be hard for Title X providers to afford to stock a lot of IUDs and implants, though. Ricketts and colleagues explain that these LARC methods can cost clinics $300-$500 even with special pricing; they report, “Clinics had historically struggled to meet the demand for these two methods within their limited budgets and sliding-fee requirements, and many offered only limited numbers of LARC insertions.”

The bottom line here is that the privately funded CFPI made it possible for Colorado’s Title X providers to greatly improve their clients’ access to LARCs. Before the initiative, only 5% of Title X female clients ages 15-24 used LARC methods; by 2011, that climbed to 19%. Statewide, the birth rate for teens ages 15-19 dropped 26%. Researchers also examined abortion rates for this age group in 37 counties where Title X-funded clinics are located and those in 27 “non-CFPI” counties. They found a 34% drop in abortions among teens ages 15-19 in CFPI counties, and a drop of 29% in non-CFPI counties. Ricketts and her colleagues point out that teens living in non-CFPI counties may well cross county lines to receive family-planning services, so the initiative may have helped lower abortion rates statewide.

Lowering teen birth and abortion rates is a worthwhile public health goal on its own, but state officials with competing funding priorities will also want to know whether funding LARCs for lower-income women might let them reduce spending in other areas. The WIC infant caseload is a leading indicator of low-income births, because researchers can access WIC caseload data well before birth certificate data are finalized, Ricketts et al explain. (WIC, or the Special Supplemental Program for Women, Infants and Children, provides nutrition education and supplemental food for low-income pregnant and postpartum women and for children up to age five who are determined to be at nutritional risk.) Ricketts and her colleagues report:

Continuing a decades-long trend, the number of infants receiving WIC benefits grew steadily in the two years preceding the Colorado Family Planning Initiative, from 24,513 in January 2007 to 26,766 in December 2008 (Figure 2). In 2009, when CFPI began, the number leveled off; it ended the year at 26,862. Subsequently, the number rose to 28,978 in March 2010 and then dropped sharply; by March 2013, it had fallen to 22,407, a level well below that for any month since early 2005. The number of infants served by WIC, which had risen 18% between January 2007 and March 2010, fell 23% in the following three-year period.

Having fewer state residents with incomes low enough to qualify them for various forms of assistance translates to lower expenditures on a variety of programs. In just a few years, Colorado’s experience has demonstrated that investing in LARC accessibility can translate quickly into savings. Benefits to the women receiving LARCs may be harder to quantify, but are substantial. “This initiative has saved Colorado millions of dollars,” said Governor John Hickenlooper in a news release announcing the findings. “But more importantly, it has helped thousands of young Colorado women continue their education, pursue their professional goals and postpone pregnancy until they are ready to start a family.”

I hope these findings (and many others published over the years showing an excellent return on family-planning investments) will prompt other states to increase their investments in family planning for lower-income women. The trend in several states and at the federal level, though, has been for family-planning budgets to fall or remain stagnant despite growing demand. Some of this is likely due to overall budget-cutting pressure, and some to hostility toward women being able to control their reproductive timelines. The evidence is clear, though: improving women’s access to effective contraception pays off financially and for public health.

from ScienceBlogs http://ift.tt/1AYI9hA