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Dates of lunar and solar eclipses in 2015 and 2016

The next eclipse is a partial eclipse of the sun on September 13, 2015, visible from the southern part of Africa. One fortnight (two weeks) after that, it’ll be a total eclipse of the year’s closest supermoon on the night of September 27-28, visible from North and South America. Follow the links below to learn more about the upcoming solar and lunar eclipses in 2015 and 2016. Enjoy.

Partial solar eclipse on September 13

Super Blood Moon eclipse on night of September 27-28

Eclipses in 2015

Eclipses in 2016

Fortnight (approximate two-week) separation between solar and lunar eclipses

The video below – showing where the September 13 eclipse will be visible – is courtesy of Larry Koehn at the great website shadowandsubstance.com:

Partial Eclipse of the Sun on September 13, 2015 from LarryKoehn on Vimeo.

Composite total solar eclipse Aug. 1999 by Fred Espenak.

This is what a total eclipse looks like. This is the total eclipse of October 27, 2004 via Fred Espenak of NASA, otherwise known as Mr. Eclipse. Visit Fred's page here.

This is what a total eclipse looks like. This is the total eclipse of October 27, 2004 via Fred Espenak of NASA. Visit Fred’s page here. We astronomy writers often describe a totally eclipsed moon as appearing ‘blood red.’ Here’s why the moon turns red during a total eclipse.

Eclipses in 2015
March 20: Total solar eclipse
April 4: Total lunar eclipse
September 13: Partial solar eclipse
September 28: Total lunar eclipse

Eclipses in 2016
March 9: Total solar eclipse
March 23: Penumbral lunar eclipse
September 1: Annular solar eclipse
September 16: Penumbral lunar eclipse

Fortnight (approximate two-week) separation between solar and lunar eclipses. A solar eclipse always takes place within one fortnight of any lunar eclipse. For instance, in 2015, the total solar eclipse on March 20 comes one fortnight before the Blood Moon total lunar eclipse of April 4. The partial solar eclipse on September 13 occurs one fortnight before the Blood Moon total lunar eclipse of September 28. In 2016, the total solar eclipse of March 9 happens one fortnight before the penumbral lunar eclipse of March 23; and the September 1 annular solar eclipse takes place one fortnight before the September 16 penumbral lunar eclipse.

Somewhat rarely, a solar eclipse can occur one fortnight before and after a lunar eclipse. This will next happen in the year 2018:
July 13: Partial solar eclipse
July 27: Total lunar eclipse
August 11: Partial solar eclipse

Somewhat rarely, a lunar eclipse can come one fortnight before and after a solar eclipse. This will next happen in the year 2020:
June 5: Penumbral lunar eclipse
June 21: Annular solar eclipse
July 5: Penumbral lunar eclipse

Animation of the September 28, 2015, total lunar eclipse, whereby the moon passes through the southern half of the Earth's shadow from west to east. The horizontal yellow line depicts the ecliptic - Earth's orbital plane projected onto the dome of sky. The inner bull's-eye shadow depicts the umbra (dark shadow) and the shadow encircling the umbra represents the penumbra (faint shadow).

Animation of the September 28, 2015, total lunar eclipse. Moon passes through southern half of the Earth’s shadow from west to east. Horizontal yellow line depicts the ecliptic – Earth’s orbital plane projected onto the dome of sky. The inner bull’s-eye shadow depicts the umbra (dark shadow). The penumbra (faint shadow) encircles the umbra.

Bottom line: Dates of solar and lunar eclipses in 2015 and 2016.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

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Partial solar eclipse on September 13

Super Blood Moon eclipse on night of September 27-28

Eclipses in 2015

Eclipses in 2016

Fortnight (approximate two-week) separation between solar and lunar eclipses

The video below – showing where the September 13 eclipse will be visible – is courtesy of Larry Koehn at the great website shadowandsubstance.com:

Partial Eclipse of the Sun on September 13, 2015 from LarryKoehn on Vimeo.

Composite total solar eclipse Aug. 1999 by Fred Espenak.

Eclipses in 2015
March 20: Total solar eclipse
April 4: Total lunar eclipse
September 13: Partial solar eclipse
September 28: Total lunar eclipse

Eclipses in 2016
March 9: Total solar eclipse
March 23: Penumbral lunar eclipse
September 1: Annular solar eclipse
September 16: Penumbral lunar eclipse

Bottom line: Dates of solar and lunar eclipses in 2015 and 2016.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

from EarthSky http://ift.tt/1Bz2kkB

Star of the week: Alpha Cephei, a rapidly rotating star

The constellation Cepheus the King is not terribly conspicuous and can boast of only one relatively star. That star is Alderamin – aka Alpha Cephei – which is by far the brightest star in Cepheus, lighting up one corner of an otherwise faint house-shaped pattern of stars. While not one of the most conspicuous stars in the night sky, this star is easy to spot, and it is interesting for its rapid rotation on its axis. Follow the links below to learn more about Alderamin, aka Alpha Cephei.

Science of Alpha Cephei

How to find Alpha Cephei

Alpha Cephei in the history of astronomy

$Astornomers used the CHARA array to learn the inclination, polar and equatorial radius and temperature, as well as the fractional rotation speed of Alpha Cephei. Read about this work here.$

Astronomers used the CHARA array at Georgia State University – optical interferometer – to learn the inclination, polar and equatorial radius and temperature, as well as the rotation speed of Alpha Cephei. Read about this work here.

Science of Alpha Cephei. Alderamin is a white star; it’s considered a Class A star, which is now evolving off of the main sequence into a subgiant. It’s thought that this star is now on its way to becoming a red giant as its internal supply of hydrogen fuel runs low.

According to the star expert Jim Kaler, Alderamin shines with the luminosity of 18 suns.

Alpha Cephei rotates rapidly. It completes one revolution in less than 12 hours, in contrast to nearly a month for our sun to turn on its axis. Jim Kaler writes of this star:

The spin may also be related to the star’s activity. [Our] sun is magnetically active in broad part because its outer third is churning up and down in huge convective currents, the movement helping to generate a magnetic field. Such outer zones are supposed to disappear in class A stars like Alderamin. Yet Alderamin emits about the same amount of X-ray radiation as does the sun and has other features that together suggest considerable magnetic activity. No one really knows why. Such anomalies, of course, drive the science. Understanding Alderamin will someday help us understand our own star, on which we depend for life.

By the way, Alpha Cephei is not a very powerful star in contrast to Cepheus’ two king-sized stars: Mu Cephei (the Garnet Star) and VV (two V’s) Cephei. Mu Cephei and VV Cephei are supergiants – among the largest and brightest in our Milky Way galaxy – shining with the firepower of hundreds of thousands of suns. If either star were to replace the sun in our solar system, its diameter would extend beyond the orbit of the planet Jupiter, which lies a good five times farther out from our sun than Earth does. Although both of these stars appear faint, only visible to the unaided eye on a dark, moonless night, it’s because they’re so distant, residing a few thousand light-years away.

Meanwhile, Alderamin is only 49 light-years away.

View larger. The constellation Cepheus the King has the shape of the house we all drew as children. Alderamin is by far the brightest star in this constellation.

View larger. The constellation Cepheus the King has the shape of the house we all drew as children. Alderamin, or Alpha Cephei, is by far the brightest star in this constellation. A line drawn between Schedar and Caph in the constellation Cassiopeia will lead you to Alpha Cephei.

How to find Alpha Cephei. On a dark night, Alpha Cephei is easily visible and also relatively easy to find. Look northward for this star. It is circumpolar throughout all of Europe, northern Asia, Canada and American cities as far south as San Diego. Its constellation, Cepheus, has the shape of the stick house we all drew as children. Cepheus is a rather faint constellation, but Alpha Cephei is by far its brightest star and is easily observable to the unaided eye, even in cities.

If you know the W or M-shaped constellation Cassiopeia the Queen, you can use the Cassiopeia stars Schedar and Caph to star-hop to Alderamin.

Sky chart of the constellation Cepheus the King

Alpha Cephei in the history of astronomy. Alpha Cephei has been a pole star in the past, that is, a star close to the sky’s north pole. The last time was in 18,000 BC. It will again be a pole star some 5,500 years from now. What kind of world will Earth be then? No matter. The heavens will pursue their long cycles, and Alpha Cephei will lie some three degrees from the sky’s north pole around the year 7500 CE. That means it won’t be as good a pole star as our present-day Polaris, which will be 0.4525 degrees from the north celestial pole in on March 24, 2100. But it’ll be pretty good.

This star’s proper name, Alderamin, is from the Arabic and means “the right arm,” presumably of Cepheus the King, who played a role in Greek mythology.

Bottom line: Cepheus the King is not a very conspicuous constellation and has only one relatively bright star, Alderamin – aka Alpha Cephei. This star is interesting for its rapid rotation on its axis.

Star Errai: Future North Star

Schedar: Short life of burning bright

from EarthSky http://ift.tt/SxAPFU

Science of Alpha Cephei

How to find Alpha Cephei

Alpha Cephei in the history of astronomy

$Astornomers used the CHARA array to learn the inclination, polar and equatorial radius and temperature, as well as the fractional rotation speed of Alpha Cephei. Read about this work here.$

According to the star expert Jim Kaler, Alderamin shines with the luminosity of 18 suns.

Alpha Cephei rotates rapidly. It completes one revolution in less than 12 hours, in contrast to nearly a month for our sun to turn on its axis. Jim Kaler writes of this star:

The spin may also be related to the star’s activity. [Our] sun is magnetically active in broad part because its outer third is churning up and down in huge convective currents, the movement helping to generate a magnetic field. Such outer zones are supposed to disappear in class A stars like Alderamin. Yet Alderamin emits about the same amount of X-ray radiation as does the sun and has other features that together suggest considerable magnetic activity. No one really knows why. Such anomalies, of course, drive the science. Understanding Alderamin will someday help us understand our own star, on which we depend for life.

Meanwhile, Alderamin is only 49 light-years away.

If you know the W or M-shaped constellation Cassiopeia the Queen, you can use the Cassiopeia stars Schedar and Caph to star-hop to Alderamin.

Sky chart of the constellation Cepheus the King

This star’s proper name, Alderamin, is from the Arabic and means “the right arm,” presumably of Cepheus the King, who played a role in Greek mythology.

Star Errai: Future North Star

Schedar: Short life of burning bright

from EarthSky http://ift.tt/SxAPFU

Climate Change Plus Irreversable Evolution Will Force Key Ocean Bacteria into Overdrive [Greg Laden's Blog]

I’ve got a press release from the University of Southern California that seems important, but I don’t have time today to read the study. So, you can look at the press release and tell me what you think of it.

Climate Change Will Irreversibly Force Key Ocean Bacteria into Overdrive

Scientists demonstrate that a key organism in the ocean’s foodweb will start reproducing at high speed as carbon dioxide levels rise, with no way to stop when nutrients become scarce

Imagine being in a car with the gas pedal stuck to the floor, heading toward a cliff’s edge. Metaphorically speaking, that’s what climate change will do to the key group of ocean bacteria known as Trichodesmium, scientists have discovered.

Trichodesmium (called “Tricho” for short by researchers) is one of the few organisms in the ocean that can “fix” atmospheric nitrogen gas, making it available to other organisms. It is crucial because all life — from algae to whales — needs nitrogen to grow.

A new study from USC and the Massachusetts-based Woods Hole Oceanographic Institution (WHOI) shows that changing conditions due to climate change could send Tricho into overdrive with no way to stop — reproducing faster and generating lots more nitrogen. Without the ability to slow down, however, Tricho has the potential to gobble up all its available resources, which could trigger die-offs of the microorganism and the higher organisms that depend on it.

By breeding hundreds of generations of the bacteria over the course of nearly five years in high-carbon dioxide ocean conditions predicted for the year 2100, researchers found that increased ocean acidification evolved Tricho to work harder, producing 50 percent more nitrogen, and grow faster.

The problem is that these amped-up bacteria can’t turn it off even when they are placed in conditions with less carbon dioxide. Further, the adaptation can’t be reversed over time — something not seen before by evolutionary biologists, and worrisome to marine biologists, according to David Hutchins, lead author of the study.

“Losing the ability to regulate your growth rate is not a healthy thing,” said Hutchins, professor at the USC Dornsife College of Letters, Arts and Sciences. “The last thing you want is to be stuck with these high growth rates when there aren’t enough nutrients to go around. It’s a losing strategy in the struggle to survive.”

Tricho needs phosphorous and iron, which also exist in the ocean in limited supply. With no way to regulate its growth, the turbo-boosted Tricho could burn through all of its available nutrients too quickly and abruptly die off, which would be catastrophic for all other life forms in the ocean that need the nitrogen it would have produced to survive.

Some models predict that increasing ocean acidification will exacerbate the problem of nutrient scarcity by increasing stratification of the ocean — locking key nutrients away from the organisms that need them to survive.

Hutchins is collaborating with Eric Webb of USC Dornsife and Mak Saito of WHOI to gain a better understanding of what the future ocean will look like, as it continues to be shaped by climate change. They were shocked by the discovery of an evolutionary change that appears to be permanent — something Hutchins described as “unprecedented.”

“Tricho has been studied for ages. Nobody expected that it could do something so bizarre,” he said. “The evolutionary biologists are interested in it just to study this as a basic evolutionary principle.”

The team is now studying the DNA of Tricho to try to find out how and why the irreversible evolution occurs. Earlier this year, research led by Webb found that Tricho’s DNA inexplicably contains elements that are usually only seen in higher life forms.

“Our results in this and the aforementioned study are truly surprising. Furthermore, they are giving us an improved, view of how global climate change will impact Trichodesmium and the vital supplies of new nitrogen it provides to the rest of the marine food web in the future.” Webb said.

The research appears in Nature Communications on September 1. It can be found online at: http://ift.tt/1EzomrZ

The abstract of the study is here:

Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean.

from ScienceBlogs http://ift.tt/1L0XDRP

Climate Change Will Irreversibly Force Key Ocean Bacteria into Overdrive

Scientists demonstrate that a key organism in the ocean’s foodweb will start reproducing at high speed as carbon dioxide levels rise, with no way to stop when nutrients become scarce

The research appears in Nature Communications on September 1. It can be found online at: http://ift.tt/1EzomrZ

The abstract of the study is here:

Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean.

from ScienceBlogs http://ift.tt/1L0XDRP

Slowing global warming would save piles of money [Greg Laden's Blog]

The Citi Global Perspectives and Solutions thingie, part of Citibank, has done a study that you can read here. It says that addressing global warming makes economic sense. So, when those science deniers are out there denying climate change they are also denying arithmetic. Shame on them.

Dana Nuccitelli, author of Climatology versus Pseudoscience and Guardian Blogger, wrote up the report at Skeptical Science:

Citi Global Perspectives & Solutions (GPS), a division within Citibank (America’s third-largest bank), recently published a report looking at the economic costs and benefits of a low-carbon future. The report considered two scenarios: “Inaction,” which involves continuing on a business-as-usual path, and Action scenario which involves transitioning to a low-carbon energy mix.

One of the most interesting findings in the report is that the investment costs for the two scenarios are almost identical. In fact, because of savings due to reduced fuel costs and increased energy efficiency, the Action scenario is actually a bit cheaper than the Inaction scenario.

Go read Dana’s writeup. There are flow charts and a pie diagram!

from ScienceBlogs http://ift.tt/1L0XBcS

Dana Nuccitelli, author of Climatology versus Pseudoscience and Guardian Blogger, wrote up the report at Skeptical Science:

Citi Global Perspectives & Solutions (GPS), a division within Citibank (America’s third-largest bank), recently published a report looking at the economic costs and benefits of a low-carbon future. The report considered two scenarios: “Inaction,” which involves continuing on a business-as-usual path, and Action scenario which involves transitioning to a low-carbon energy mix.

One of the most interesting findings in the report is that the investment costs for the two scenarios are almost identical. In fact, because of savings due to reduced fuel costs and increased energy efficiency, the Action scenario is actually a bit cheaper than the Inaction scenario.

Go read Dana’s writeup. There are flow charts and a pie diagram!

from ScienceBlogs http://ift.tt/1L0XBcS

Tristes Tropiques [Greg Laden's Blog]

Not the book (which is good) but the thing. The storms, really.

I may have mentioned the pilot whales I saw in San Diego the other day. You’ve heard about changes in shark distributions, and odd fish being caught in unusual places, etc. This is all about changes in the Pacific as increased global warming affects ocean ecology. Inside Climate News has this:

Warmer North Pacific Is Staying Warmer, With Dramatic Impact on Marine Life
Ocean temperature fluctuations have slowed, a new study says, with an extended warm period in the N. Pacific causing a massive shift in marine life.

One study suggests that there may be a new, but small, hurricane basin in the future: Climate change brings cyclone risk to Persian Gulf: study

See the graphic above. We are experiencing yet another “oh wow” event in the tropics, which seem to be littered with cyclones. Check out the details at the Weather Underground tropical storm section.

We like to go to dry places, they are sunny, don’t smell like mildew, and generally make great destinations. But they are spots, fixed in space, on the landscape, and with climate change they are affected and can’t just get up and move. See: The Coolest Places We’re Losing to the Drought

Jeff Masters talks about Fred. This is the first fully formed hurricane since 1892 to hit the Cape Verde, and is likely the farthest east forming hurricane on record. By the time you read this Fred will be a big wet smear rather than a hurricane, but during its short life it set some interesting records.

from ScienceBlogs http://ift.tt/1KDqDU5

Not the book (which is good) but the thing. The storms, really.

Warmer North Pacific Is Staying Warmer, With Dramatic Impact on Marine Life
Ocean temperature fluctuations have slowed, a new study says, with an extended warm period in the N. Pacific causing a massive shift in marine life.

One study suggests that there may be a new, but small, hurricane basin in the future: Climate change brings cyclone risk to Persian Gulf: study

from ScienceBlogs http://ift.tt/1KDqDU5

Who thinks what about climate change and science? [Greg Laden's Blog]

Two items of interest.

1) A new poll looks at conservative and liberal views of science. The findings are not especially unexpected, but the details are interesting. The image above is from this infographic, and the details are given here.

Yes, the detail are quite interesting.

2) If you care, there is some information on what the 2016 GOP candidates stand on climate change.

This is put together by CBS and is here.

from ScienceBlogs http://ift.tt/1KDqD6o

Two items of interest.

Yes, the detail are quite interesting.

2) If you care, there is some information on what the 2016 GOP candidates stand on climate change.

This is put together by CBS and is here.

from ScienceBlogs http://ift.tt/1KDqD6o

Climate Change Viewed From Alaska [Greg Laden's Blog]

Alaska is being called the poster child (state?) for climate change because things have been so strange there lately. One reason for this is the extreme warm conditions in the North Pacific and associated (probably) changes in the jet stream, as well as overall warming, which has caused coastal Alaska to become a warm place, glaciers to melt, and (in the farther north) sea ice to be less. And now, President Obama has made a trip there and given a big speech.

President Obama’s speech:

More information on the President’s trip here.

Meanwhile, another study cites arctic ice loss as a factor in extreme events.

The new study, published Monday in the journal Nature Geoscience, advances a growing body of science demonstrating that these record-breaking extremes have not been a pause in the advance of human-driven climate change but a result of it.

The newly published study, led by Jong-Seong Kug of South Korea’s Pohang University of Science and Technology, used climate and weather observations as well as climate change modeling to investigate potential connections between these and other extreme cold winter weather systems over North America and South Asia last winter and historically low levels of summer sea ice in areas of the Arctic Ocean.

I’ve written about this quite a bit before. See:

Linking Weather Extremes to Global Warming

Imperfect Storms: A Controversy In Climate Science

Global Warming and Extreme Weather – #climate #agw

The top of the Earth burns, makes Global Warming Worse

More Research Linking Global Warming To Bad Weather Events

Global Warming Changing Weather in the US Northeast

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