Course Report: Brief History of Timekeeping [Uncertain Principles]

A few years ago, I taught one of our “SRS” classes, which are supposed to introduce students to research at the college level– I blogged about it while the course was in progress. I taught it again in the recently-concluded Winter term, but didn’t blog much about it because I was mostly doing the same stuff as last time. I did re-adjust the content a little, as I’ve changed some things about the way I like to present stuff since 2012, but they were mostly cosmetic tweaks, with one big exception.


In the previous round, I went with the base course description, which just specifies that students must write a research paper, and ended up getting 17 library research papers. Most of which were very well done, but there’s only so many library research papers I can read. This time, having had a number of arguments about whether this is really a “research methods” course, I opted instead to require final projects. Since I’m a scientist, and science is about empirical measurements of things, I insisted that every student had to select a project related to timekeeping in which they made an empirical measurement of… something related to timekeeping.


I was a little nervous about this, because it’s a slightly unusual kind of assignment, and I wasn’t sure how it would go over. And I was also slightly concerned that I would get a dozen variants of experiments we did or discussed in class. But, on the whole, I was extremely impressed with both the quality and the range of the projects I got.


The “featured image” up top (and reproduced below for the RSS crowd) shows a few snapshots from the final papers, showing some of my favorite results. On the left, we have a student who decided to test the performance of different materials for a sandglass, who saw a mention of powdered eggshell as a material in one of the papers we read in class, and made powdered eggshells to test (which turns out to be a multi-step process…). In the center, we have a homemade water wheel clock, with two reservoirs using an overflow system to maintain a constant level in the second, and the outflow from that powering a wheel whose time he tracked. And on the right, we have a plastic pendulum constructed by a woman who chose to take advantage of this awful winter’s weather, to measure the effect of thermal expansion on the period by recording the period indoors and outside on a bitter cold day.


Student projects from my SRS (L to R): Measuring the flow of powdered eggshell in a "sand timer," a homemade water wheel clock, and a pendulum to measure the effect of thermal expansion.

Student projects from my SRS (L to R): Measuring the flow of powdered eggshell in a “sand timer,” a homemade water wheel clock, and a pendulum to measure the effect of thermal expansion.



Not pictured are another water clock, an analog metronome, a guy who compared three quartz watches at different temperatures, and another guy who bought a mechanical pocket watch and tracked its performance. We did have several sundials, but those were generally well-done as well, and each of the students working with sundials found a unique approach.


So, on the whole, a very positive experience. Five stars, would do again. I don’t know how this will play out in terms of course comments from the students– those are held up for a couple of weeks because computers– but a couple of the students did append nice notes with their final papers saying “Thanks for having us build something, I really enjoyed it.” And as a faculty member, that’s a great feeling.


This term, I’m teaching intro calculus-based classical mechanics for the first time in a few years; two sections of it, no less. Which is going to be grueling, but there’s a sabbatical waiting at the end of it, so I’ll get through…






from ScienceBlogs http://ift.tt/1GLd42d

A few years ago, I taught one of our “SRS” classes, which are supposed to introduce students to research at the college level– I blogged about it while the course was in progress. I taught it again in the recently-concluded Winter term, but didn’t blog much about it because I was mostly doing the same stuff as last time. I did re-adjust the content a little, as I’ve changed some things about the way I like to present stuff since 2012, but they were mostly cosmetic tweaks, with one big exception.


In the previous round, I went with the base course description, which just specifies that students must write a research paper, and ended up getting 17 library research papers. Most of which were very well done, but there’s only so many library research papers I can read. This time, having had a number of arguments about whether this is really a “research methods” course, I opted instead to require final projects. Since I’m a scientist, and science is about empirical measurements of things, I insisted that every student had to select a project related to timekeeping in which they made an empirical measurement of… something related to timekeeping.


I was a little nervous about this, because it’s a slightly unusual kind of assignment, and I wasn’t sure how it would go over. And I was also slightly concerned that I would get a dozen variants of experiments we did or discussed in class. But, on the whole, I was extremely impressed with both the quality and the range of the projects I got.


The “featured image” up top (and reproduced below for the RSS crowd) shows a few snapshots from the final papers, showing some of my favorite results. On the left, we have a student who decided to test the performance of different materials for a sandglass, who saw a mention of powdered eggshell as a material in one of the papers we read in class, and made powdered eggshells to test (which turns out to be a multi-step process…). In the center, we have a homemade water wheel clock, with two reservoirs using an overflow system to maintain a constant level in the second, and the outflow from that powering a wheel whose time he tracked. And on the right, we have a plastic pendulum constructed by a woman who chose to take advantage of this awful winter’s weather, to measure the effect of thermal expansion on the period by recording the period indoors and outside on a bitter cold day.


Student projects from my SRS (L to R): Measuring the flow of powdered eggshell in a "sand timer," a homemade water wheel clock, and a pendulum to measure the effect of thermal expansion.

Student projects from my SRS (L to R): Measuring the flow of powdered eggshell in a “sand timer,” a homemade water wheel clock, and a pendulum to measure the effect of thermal expansion.



Not pictured are another water clock, an analog metronome, a guy who compared three quartz watches at different temperatures, and another guy who bought a mechanical pocket watch and tracked its performance. We did have several sundials, but those were generally well-done as well, and each of the students working with sundials found a unique approach.


So, on the whole, a very positive experience. Five stars, would do again. I don’t know how this will play out in terms of course comments from the students– those are held up for a couple of weeks because computers– but a couple of the students did append nice notes with their final papers saying “Thanks for having us build something, I really enjoyed it.” And as a faculty member, that’s a great feeling.


This term, I’m teaching intro calculus-based classical mechanics for the first time in a few years; two sections of it, no less. Which is going to be grueling, but there’s a sabbatical waiting at the end of it, so I’ll get through…






from ScienceBlogs http://ift.tt/1GLd42d

What’s the birthstone for April?


Photo credit: Kim Alianz

Photo credit: Kim Alianz





April’s birthstone is the diamond.

Diamonds are the rich cousins of graphite. Both are crystalline forms of pure carbon. The enormous differences in their properties are a result of the way the carbon atoms are bonded together. In graphite, carbon atoms are arranged in sheets that easily slide past each other, which makes graphite ideal as a lubricant and, of course, pencil lead. Diamond crystals, on the other hand, are a tight-fisted network of carbon atoms securely held in four directions, making it the hardest naturally-occurring substance in the world.


In order to achieve such a compact and strongly-held network of carbon atoms, it is believed that diamonds must have crystallized deep under the Earth’s surface. At these depths the proper conditions for the formation of diamonds exist; at 90 to 120 miles deep, pressures are more than 65,000 times that of the atmosphere at the Earth’s surface, with temperatures exceeding 2,700 degrees Fahrenheit. Such pressures and temperatures reproduced in laboratories have successfully yielded synthetic diamonds.


There are many kinds of diamonds: transparent, translucent, or opaque; ranging from colorless to sooty black, with many colors in between. Mostly transparent diamonds, colorless or tinted, are used as jewelry. Others are used widely in industry. The color of a diamond depends on the kind of impurities embedded inside it. Yellow diamonds, for example, betray minute quantities of nitrogen, while boron imparts a bluish hue. There are other inclusions in diamonds that have great scientific value. Such samples are time capsules that yield valuable information about conditions deep in the Earth’s upper mantle where diamonds formed, as well as clues to the formation and age of the diamond.


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Diamonds are found in alluvial deposits – gravel swept by streams, rivers, glaciers, and ocean currents. They are also found in sedimentary rock where gravel deposits and organic material have been compressed into rock. Diamonds can be found in some samples of kimberlite – a type of volcanic rock first identified in Kimberley, South Africa. Diamonds found in kimberlite are thought to be very old, perhaps as much as three billion years old. Tiny flecks of diamond have even been found inside meteorites – bits of rocky space debris that land on Earth.


Diamonds are crystals. Crystals are the ultimate form of symmetry in nature. Their shape reflects the internal orderly arrangement of atoms within the crystal. In diamonds, atoms of carbon are held tightly by covalent bonding, where two neighboring atoms share an electron, endowing the diamond crystal with great strength. But despite that hardness, diamonds can be cut with saws and polished with grinding wheels coated with tiny industrial diamond fragments. In their natural form, diamonds can appear quite unimpressive. They are cut and polished by skilled craftsmen in a pattern that reflects and refracts the light among its facets to reveal the hidden beauty of the stone.


Diamonds’ cold, sparkling fire has held us spell-bound for centuries, inspiring rich, passionate myths of romance, intrigue, power, greed, and magic. Ancient Hindus, finding diamonds washed out of the ground after thunderstorms, believed they were created by bolts of lightning. In our place and time, the diamond is a symbol of enduring love, and often graces engagement rings.


diamond


Some diamonds seem to have lived lives of their own. One legendary stone in the diamond hall of fame is the Koh-i-noor (“Mountain of Light”). The Koh-i-noor diamond’s early history is shrouded in time. It is believed to be 5,000 years old, and was featured in the great Sanskrit epic The Mahabharata. Originally owned by the Rajah of Malwa in India, the Koh-i-noor has since been a player in victories and defeats spanning India, Persia, and Afghanistan. It was in the possession of the great Mogul dynasty from 1526 to 1739. Its owners included Shah Jehan, who built the Taj Mahal in memory of his queen Mumtaz. The Persian invader Nadir Shah briefly possessed it until his assassination in 1747. The jewel then fell into the hands of Afghan rulers who eventually surrendered it to the Rajah of Punjab, Ranjit Singh.


Two years after Ranjit Singh’s death in 1839, Punjab became part of India under British rule. The stone was presented to Queen Victoria, who had it cut from its original 187 carats to 108 carats in an attempt to further enhance its beauty. After her death, the diamond became part of the British crown jewels. Queen Elizabeth (later the Queen Mother) wore it in her crown at her 1937 coronation.


Find out about the birthstones for the other months of the year.

January birthstone

February birthstone

March birthstone

May birthstone

June birthstone

July birthstone

August birthstone

September birthstone

October birthstone

November birthstone

December birthstone


Image Credit: Rob Lavinsky






from EarthSky http://ift.tt/1i0DZGT

Photo credit: Kim Alianz

Photo credit: Kim Alianz





April’s birthstone is the diamond.

Diamonds are the rich cousins of graphite. Both are crystalline forms of pure carbon. The enormous differences in their properties are a result of the way the carbon atoms are bonded together. In graphite, carbon atoms are arranged in sheets that easily slide past each other, which makes graphite ideal as a lubricant and, of course, pencil lead. Diamond crystals, on the other hand, are a tight-fisted network of carbon atoms securely held in four directions, making it the hardest naturally-occurring substance in the world.


In order to achieve such a compact and strongly-held network of carbon atoms, it is believed that diamonds must have crystallized deep under the Earth’s surface. At these depths the proper conditions for the formation of diamonds exist; at 90 to 120 miles deep, pressures are more than 65,000 times that of the atmosphere at the Earth’s surface, with temperatures exceeding 2,700 degrees Fahrenheit. Such pressures and temperatures reproduced in laboratories have successfully yielded synthetic diamonds.


There are many kinds of diamonds: transparent, translucent, or opaque; ranging from colorless to sooty black, with many colors in between. Mostly transparent diamonds, colorless or tinted, are used as jewelry. Others are used widely in industry. The color of a diamond depends on the kind of impurities embedded inside it. Yellow diamonds, for example, betray minute quantities of nitrogen, while boron imparts a bluish hue. There are other inclusions in diamonds that have great scientific value. Such samples are time capsules that yield valuable information about conditions deep in the Earth’s upper mantle where diamonds formed, as well as clues to the formation and age of the diamond.


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


Diamonds are found in alluvial deposits – gravel swept by streams, rivers, glaciers, and ocean currents. They are also found in sedimentary rock where gravel deposits and organic material have been compressed into rock. Diamonds can be found in some samples of kimberlite – a type of volcanic rock first identified in Kimberley, South Africa. Diamonds found in kimberlite are thought to be very old, perhaps as much as three billion years old. Tiny flecks of diamond have even been found inside meteorites – bits of rocky space debris that land on Earth.


Diamonds are crystals. Crystals are the ultimate form of symmetry in nature. Their shape reflects the internal orderly arrangement of atoms within the crystal. In diamonds, atoms of carbon are held tightly by covalent bonding, where two neighboring atoms share an electron, endowing the diamond crystal with great strength. But despite that hardness, diamonds can be cut with saws and polished with grinding wheels coated with tiny industrial diamond fragments. In their natural form, diamonds can appear quite unimpressive. They are cut and polished by skilled craftsmen in a pattern that reflects and refracts the light among its facets to reveal the hidden beauty of the stone.


Diamonds’ cold, sparkling fire has held us spell-bound for centuries, inspiring rich, passionate myths of romance, intrigue, power, greed, and magic. Ancient Hindus, finding diamonds washed out of the ground after thunderstorms, believed they were created by bolts of lightning. In our place and time, the diamond is a symbol of enduring love, and often graces engagement rings.


diamond


Some diamonds seem to have lived lives of their own. One legendary stone in the diamond hall of fame is the Koh-i-noor (“Mountain of Light”). The Koh-i-noor diamond’s early history is shrouded in time. It is believed to be 5,000 years old, and was featured in the great Sanskrit epic The Mahabharata. Originally owned by the Rajah of Malwa in India, the Koh-i-noor has since been a player in victories and defeats spanning India, Persia, and Afghanistan. It was in the possession of the great Mogul dynasty from 1526 to 1739. Its owners included Shah Jehan, who built the Taj Mahal in memory of his queen Mumtaz. The Persian invader Nadir Shah briefly possessed it until his assassination in 1747. The jewel then fell into the hands of Afghan rulers who eventually surrendered it to the Rajah of Punjab, Ranjit Singh.


Two years after Ranjit Singh’s death in 1839, Punjab became part of India under British rule. The stone was presented to Queen Victoria, who had it cut from its original 187 carats to 108 carats in an attempt to further enhance its beauty. After her death, the diamond became part of the British crown jewels. Queen Elizabeth (later the Queen Mother) wore it in her crown at her 1937 coronation.


Find out about the birthstones for the other months of the year.

January birthstone

February birthstone

March birthstone

May birthstone

June birthstone

July birthstone

August birthstone

September birthstone

October birthstone

November birthstone

December birthstone


Image Credit: Rob Lavinsky






from EarthSky http://ift.tt/1i0DZGT

Moon swings out to apogee – farthest point – on April 1


No April Fools! The moon swings out to apogee – the moon’s farthest point from Earth in its orbit – twice in April 2015: April 1 and 29. We list the dates for this year’s 13 apogees and 13 perigees:


Shortest total lunar eclipse of the 21st century on April 4


2015




























































ApogeePerigee
January 9January 21
February 6February 19
March 5March 19
April 1April 17
April 29May 15
May 26June 10
June 23July 5
July 21August 2
August 18August 30
September 14September 28
October 11October 26
November 7November 23
December 5December 21

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Amazingly, in periods of four years, lunar apogees and perigees fall on the same, or nearly the same calendar dates. Let’s look four years ahead, to the year 2019:


2019




























































ApogeePerigee
January 9January 21
February 5February 19
March 4March 19
April 1April 16
April 28May 13
May 26June 7
June 23July 5
July 20August 2
August 17August 30
September 13September 28
October 10October 26
November 7November 23
December 5December 18

Also, in cycles of two years, the calendar dates remain the same, or nearly so, except that the lunar apogees and perigees trade places. For instance, let’s look two years beyond 2015, to the year 2017:


2017




























































ApogeePerigee
January 22January 10
February 18February 6
March 18March 3
April 15March 30
May 12April 27
June 8May 26
July 6June 23
August 2July 21
August 30August 18
September 27September 13
October 25October 9
November 21November 6
December 19December 4

Want to know more? Click here for a complete listing of all lunar perigees and apogees for the 21st century (2001 to 2100).


Intriguing cycle of farthest and closest moons


It is hard to believe that this rather straight-forward four-year apogee/perigee cycle is so little known among professional astronomers and lay people alike. Lunar apogees and lunar perigees align on the same, or nearly the same calendar dates every four years, because 53 returns to perigee is nearly commensurate with four calendar years. The mean length of the anomalistic month (perigee to perigee, or apogee to apogee) is 27.55455 days, whereas the average Gregorian year equals 365.2425 days. Hence:


27.55455 x 53 = 1460.3912 days


365.2425 x 4 = 1460.97 days


View larger. | Image via Wikipedia.

View larger. | Image via Wikipedia.



View larger. Image credit: NASA

View larger. Image credit: NASA



Bottom line: in periods of four years, lunar apogees and perigees fall on the same, or nearly the same calendar dates.






from EarthSky http://ift.tt/1C0u8Pv

No April Fools! The moon swings out to apogee – the moon’s farthest point from Earth in its orbit – twice in April 2015: April 1 and 29. We list the dates for this year’s 13 apogees and 13 perigees:


Shortest total lunar eclipse of the 21st century on April 4


2015




























































ApogeePerigee
January 9January 21
February 6February 19
March 5March 19
April 1April 17
April 29May 15
May 26June 10
June 23July 5
July 21August 2
August 18August 30
September 14September 28
October 11October 26
November 7November 23
December 5December 21

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


Amazingly, in periods of four years, lunar apogees and perigees fall on the same, or nearly the same calendar dates. Let’s look four years ahead, to the year 2019:


2019




























































ApogeePerigee
January 9January 21
February 5February 19
March 4March 19
April 1April 16
April 28May 13
May 26June 7
June 23July 5
July 20August 2
August 17August 30
September 13September 28
October 10October 26
November 7November 23
December 5December 18

Also, in cycles of two years, the calendar dates remain the same, or nearly so, except that the lunar apogees and perigees trade places. For instance, let’s look two years beyond 2015, to the year 2017:


2017




























































ApogeePerigee
January 22January 10
February 18February 6
March 18March 3
April 15March 30
May 12April 27
June 8May 26
July 6June 23
August 2July 21
August 30August 18
September 27September 13
October 25October 9
November 21November 6
December 19December 4

Want to know more? Click here for a complete listing of all lunar perigees and apogees for the 21st century (2001 to 2100).


Intriguing cycle of farthest and closest moons


It is hard to believe that this rather straight-forward four-year apogee/perigee cycle is so little known among professional astronomers and lay people alike. Lunar apogees and lunar perigees align on the same, or nearly the same calendar dates every four years, because 53 returns to perigee is nearly commensurate with four calendar years. The mean length of the anomalistic month (perigee to perigee, or apogee to apogee) is 27.55455 days, whereas the average Gregorian year equals 365.2425 days. Hence:


27.55455 x 53 = 1460.3912 days


365.2425 x 4 = 1460.97 days


View larger. | Image via Wikipedia.

View larger. | Image via Wikipedia.



View larger. Image credit: NASA

View larger. Image credit: NASA



Bottom line: in periods of four years, lunar apogees and perigees fall on the same, or nearly the same calendar dates.






from EarthSky http://ift.tt/1C0u8Pv

Researchers Study Vulnerability of Wearable Technology

How easy is it to hack a pacemaker? Your “FitBit” is designed to track your physical movements. Who else can see it?


These are among the myriad of questions Naval Surface Warfare Dahlgren Division (NSWCDD) engineer Brenden McMullen researched for six months as a member of a focus group sponsored by the Department of Homeland Security (DHS) in 2014.


The questions McMullen and his counterparts analyzed had one common denominator – “wearable and embeddable technology.”


File Photo: Sgt. Maj. Michel Pigford, the senior enlisted adviser for the Army's Performance Triad, describes the Fitbit bracelet to Master Sgt. Sandra Meyers at Fort Bragg, N.C. in 2013. (Photo: Sgt. Ferdinand Detres/10th Press Camp HQ/Released)

File Photo: Sgt. Maj. Michel Pigford, the senior enlisted adviser for the Army’s Performance Triad, describes the Fitbit bracelet to Master Sgt. Sandra Meyers at Fort Bragg, N.C. in 2013. (Photo: Sgt. Ferdinand Detres/10th Press Camp HQ/Released)



They examined surgically implanted items, such as pacemakers and telemetry, as well as wearable items ranging from physical fitness bands and chips to medical telemetry, including LifeAlert and Google Glass.


Like McMullen, scores of federal and private sector experts throughout the country volunteered their spare time to participate in the program – managed by the DHS Office of Intelligence and Analysis on behalf of the Director of National Intelligence – to identify threats, risks, and vulnerabilities associated with wearable and embeddable technologies.


“What the private sector volunteers contributed was nothing short of genius,” said McMullen. “This was a great way to engage in cutting-edge technology. The government intelligence community volunteers were equally talented, and brought the necessary contexts from their respective organizations.”


The annual initiative –officially known as the Intelligence Community Analyst-Private Sector Partnership Program – facilitates collaborative partnerships between members of the private sector and teams of experienced intelligence community analysts. It provides intelligence community analysts and private sector partners with a better understanding of select national security and homeland security issues.


“I was particularly impressed with the level of expertise and experience in the working groups,” said McMullen, whose active duty positions ranged from Naval Diving and Salvage Training Center dive instructor to Camp David medical officer before he retired as a Navy senior chief special amphibious reconnaissance corpsman. “Programs like this are important to participate in, and a great way to stay abreast with new and emerging science that impacts national security.”


Jennifer Lasley, former Department of Homeland Security, deputy undersecretary for analysis, Office of Intelligence and Analysis, also considers the volunteers’ participation important. In a letter to NSWCDD expressing appreciation for McMullen’s contribution to the program, she stressed that her DHS office and the director of National Intelligence recognize the critical value of public-private sector partnerships in contributing to the national security mission.


The effort seeks to increase the depth of expertise among the participating analysts but is not intended as a mechanism for operational activities or formal coordination between industries and the intelligence community. It enables the intelligence community and industry partners to gain insight leading to a better understanding of their respective areas of expertise.


Brenden McMullen (closest to helicopter) jumps out of the Marine Corps UH1Y over Marine Corps Base Quantico in 2006. McMullen – now a Navy civilian engineer – was recently commended for his impact on new research to identify threats, risks, and vulnerabilities related to wearable and embeddable technologies. (Photo: U.S. Marine Corps/Released)

Brenden McMullen (closest to helicopter) jumps out of the Marine Corps UH1Y over Marine Corps Base Quantico in 2006. McMullen – now a Navy civilian engineer – was recently commended for his impact on new research to identify threats, risks, and vulnerabilities related to wearable and embeddable technologies. (Photo: U.S. Marine Corps/Released)



McMullen’s military experience in ground warfare and security, and underwater and aviation environments, in addition to his current work as a Navy government civilian in antiterrorism and force protection positively impacted the group’s analytic research and deliverables, according to Lasley.


“This year’s program would not have been a success without Brenden’s active engagement and partnership,” she said. “We were particularly impressed by the diversity of analytic deliverables the teams created, and we will ensure each team’s products are widely disseminated to include posting on the DHS Homeland Security Information Network, as well as other information sharing environments.”


McMullen was the only DoD civilian in his group, which included private sector members from Disney, Monsanto, and St. Jude’s Medical. Intelligence community members in the focus group represented the Defense Intelligence Agency, National Security Agency, FBI, and DHS.


Story and information provided by the Naval Surface Warfare Center Dahlgren Division

Follow Armed with Science on Facebook and Twitter!


———-


Disclaimer: The appearance of hyperlinks does not constitute endorsement by the Department of Defense of this website or the information, products or services contained therein. For other than authorized activities such as military exchanges and Morale, Welfare and Recreation sites, the Department of Defense does not exercise any editorial control over the information you may find at these locations. Such links are provided consistent with the stated purpose of this DOD website.






from Armed with Science http://ift.tt/19DSRy6

How easy is it to hack a pacemaker? Your “FitBit” is designed to track your physical movements. Who else can see it?


These are among the myriad of questions Naval Surface Warfare Dahlgren Division (NSWCDD) engineer Brenden McMullen researched for six months as a member of a focus group sponsored by the Department of Homeland Security (DHS) in 2014.


The questions McMullen and his counterparts analyzed had one common denominator – “wearable and embeddable technology.”


File Photo: Sgt. Maj. Michel Pigford, the senior enlisted adviser for the Army's Performance Triad, describes the Fitbit bracelet to Master Sgt. Sandra Meyers at Fort Bragg, N.C. in 2013. (Photo: Sgt. Ferdinand Detres/10th Press Camp HQ/Released)

File Photo: Sgt. Maj. Michel Pigford, the senior enlisted adviser for the Army’s Performance Triad, describes the Fitbit bracelet to Master Sgt. Sandra Meyers at Fort Bragg, N.C. in 2013. (Photo: Sgt. Ferdinand Detres/10th Press Camp HQ/Released)



They examined surgically implanted items, such as pacemakers and telemetry, as well as wearable items ranging from physical fitness bands and chips to medical telemetry, including LifeAlert and Google Glass.


Like McMullen, scores of federal and private sector experts throughout the country volunteered their spare time to participate in the program – managed by the DHS Office of Intelligence and Analysis on behalf of the Director of National Intelligence – to identify threats, risks, and vulnerabilities associated with wearable and embeddable technologies.


“What the private sector volunteers contributed was nothing short of genius,” said McMullen. “This was a great way to engage in cutting-edge technology. The government intelligence community volunteers were equally talented, and brought the necessary contexts from their respective organizations.”


The annual initiative –officially known as the Intelligence Community Analyst-Private Sector Partnership Program – facilitates collaborative partnerships between members of the private sector and teams of experienced intelligence community analysts. It provides intelligence community analysts and private sector partners with a better understanding of select national security and homeland security issues.


“I was particularly impressed with the level of expertise and experience in the working groups,” said McMullen, whose active duty positions ranged from Naval Diving and Salvage Training Center dive instructor to Camp David medical officer before he retired as a Navy senior chief special amphibious reconnaissance corpsman. “Programs like this are important to participate in, and a great way to stay abreast with new and emerging science that impacts national security.”


Jennifer Lasley, former Department of Homeland Security, deputy undersecretary for analysis, Office of Intelligence and Analysis, also considers the volunteers’ participation important. In a letter to NSWCDD expressing appreciation for McMullen’s contribution to the program, she stressed that her DHS office and the director of National Intelligence recognize the critical value of public-private sector partnerships in contributing to the national security mission.


The effort seeks to increase the depth of expertise among the participating analysts but is not intended as a mechanism for operational activities or formal coordination between industries and the intelligence community. It enables the intelligence community and industry partners to gain insight leading to a better understanding of their respective areas of expertise.


Brenden McMullen (closest to helicopter) jumps out of the Marine Corps UH1Y over Marine Corps Base Quantico in 2006. McMullen – now a Navy civilian engineer – was recently commended for his impact on new research to identify threats, risks, and vulnerabilities related to wearable and embeddable technologies. (Photo: U.S. Marine Corps/Released)

Brenden McMullen (closest to helicopter) jumps out of the Marine Corps UH1Y over Marine Corps Base Quantico in 2006. McMullen – now a Navy civilian engineer – was recently commended for his impact on new research to identify threats, risks, and vulnerabilities related to wearable and embeddable technologies. (Photo: U.S. Marine Corps/Released)



McMullen’s military experience in ground warfare and security, and underwater and aviation environments, in addition to his current work as a Navy government civilian in antiterrorism and force protection positively impacted the group’s analytic research and deliverables, according to Lasley.


“This year’s program would not have been a success without Brenden’s active engagement and partnership,” she said. “We were particularly impressed by the diversity of analytic deliverables the teams created, and we will ensure each team’s products are widely disseminated to include posting on the DHS Homeland Security Information Network, as well as other information sharing environments.”


McMullen was the only DoD civilian in his group, which included private sector members from Disney, Monsanto, and St. Jude’s Medical. Intelligence community members in the focus group represented the Defense Intelligence Agency, National Security Agency, FBI, and DHS.


Story and information provided by the Naval Surface Warfare Center Dahlgren Division

Follow Armed with Science on Facebook and Twitter!


———-


Disclaimer: The appearance of hyperlinks does not constitute endorsement by the Department of Defense of this website or the information, products or services contained therein. For other than authorized activities such as military exchanges and Morale, Welfare and Recreation sites, the Department of Defense does not exercise any editorial control over the information you may find at these locations. Such links are provided consistent with the stated purpose of this DOD website.






from Armed with Science http://ift.tt/19DSRy6

Spring means these 4 hibernators are waking up


With the onset of spring in the Northern Hemisphere, animals that hibernate are waking up from a long-period of deep sleep. They spent the winter hibernating to conserve energy when food was scarce. Animals that hibernate include bats, black bears, Arctic ground squirrels, and common poorwill birds. Many other species such as raccoons and skunks go into a state of torpor during the cold weather, which is a type of light hibernation. Most hibernators wake up during the months of March and April, but some do so as late as May.


Little brown bat. Image Credit: Ann Froschauer, U.S. Fish and Wildlife Service.

Little brown bat. Image Credit: Ann Froschauer, U.S. Fish and Wildlife Service.



Bats

Many types of bats hibernate through the long, cold winter in caves. Bats that hibernate include the little brown bat, the big brown bat, and the northern long-eared bat. During hibernation, their body temperature, heart rate, breathing rate, and metabolism drop to very low levels. This allows them to get by without food or water and stay in a dormant state for long periods of time.


Black bear. Image Credit: U.S. Fish and Wildlife Service.

Black bear. Image Credit: U.S. Fish and Wildlife Service.



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Black bears

Yes, black bears do hibernate. There has been some controversy over whether or not black bears are true hibernators because their body temperature does not drop very low during the winter. However, they do undergo many metabolic changes during the winter that allow them to survive many months without food or water. Hence, several scientists do classify them as hibernators.


Arctic ground squirrel. Image Credit: Kristine Sowl, U.S. Fish and Wildlife Service.

Arctic ground squirrel. Image Credit: Kristine Sowl, U.S. Fish and Wildlife Service.



Arctic ground squirrels

During the onset of cold weather, Arctic ground squirrels dig deep burrows in the ground and hibernate. One scientist attached temperatures sensors to their abdomens and recorded body temperatures in hibernating squirrels as low as -2.9 degrees Celsius (26.8 degrees Fahrenheit), which is below the temperature that water freezes! The squirrel’s blood, however, does not freeze in part because it is salty and also because they have some sort of “super cool” supercooling mechanism that protects them. Scientists are actively researching the brain activity of hibernating Arctic ground squirrels for insights into how to protect people from neurodegenerative diseases like Alzheimer’s and to help them recover from brain injuries. Specifically, the brains of Arctic ground squirrels show a remarkable ability to bounce back after months of dormancy that degrades neuronal connections.


Watercolor painting of the common poorwill by Louise Agassiz Fuertes. Image Credit: Wikimedia Commons.

Watercolor painting of the common poorwill by Louise Agassiz Fuertes. Image Credit: Wikimedia Commons.



Common poorwill

Most birds migrate south when the weather turns cold, but the common poorwill stays put and hibernates. Poorwills are the only bird species known to hibernate. They can be found in the western United States and Canada. Native Americans often referred to this bird as “the sleeping one.”


Torpor is a state of light hibernation that many animals enter into to survive the winter. Animals that use torpor as a survival strategy include raccoons and skunks. While there is no bright line that separates animals that hibernate from those that use torpor, it generally comes down to the length of time that an animal spends in dormancy and the extent to which its body temperature and metabolic rate are depressed. Torpor is associated with brief periods of dormancy, sometimes for only a few hours, and small physiological changes, whereas hibernation is associated with lengthy periods of dormancy and large physiological changes.


Scientists use the term brumation to refer to hibernating-like states in reptiles, which are not warm-blooded animals so the physiological responses are a bit different from those in mammals and birds. Insects enter cold-induced dormant periods too, and this is referred to by the term diapause. Often on the internet, the term hibernation will be used as a catch-all phrase for all of these types of dormant states.


The exact triggers that cause an animal to enter into and emerge from hibernation aren’t well known, but combinations of factors such as changes in temperature, daylight, and food availability are thought to play an important role. Especially critical is an animal’s internal biological clock, which will initiate hormone changes when it is time for the animal to wake up.


Bottom line: Hibernation is a survival strategy that animals use during the winter to conserve energy when food is scarce. Animals that hibernate include bats, black bears, Arctic ground squirrels, and common poorwill birds.


What we didn’t know about hibernating black bears


Spring may come earlier to North American forests


Why does Earth have four seasons?






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With the onset of spring in the Northern Hemisphere, animals that hibernate are waking up from a long-period of deep sleep. They spent the winter hibernating to conserve energy when food was scarce. Animals that hibernate include bats, black bears, Arctic ground squirrels, and common poorwill birds. Many other species such as raccoons and skunks go into a state of torpor during the cold weather, which is a type of light hibernation. Most hibernators wake up during the months of March and April, but some do so as late as May.


Little brown bat. Image Credit: Ann Froschauer, U.S. Fish and Wildlife Service.

Little brown bat. Image Credit: Ann Froschauer, U.S. Fish and Wildlife Service.



Bats

Many types of bats hibernate through the long, cold winter in caves. Bats that hibernate include the little brown bat, the big brown bat, and the northern long-eared bat. During hibernation, their body temperature, heart rate, breathing rate, and metabolism drop to very low levels. This allows them to get by without food or water and stay in a dormant state for long periods of time.


Black bear. Image Credit: U.S. Fish and Wildlife Service.

Black bear. Image Credit: U.S. Fish and Wildlife Service.



Have you donated yet in EarthSky’s annual fund-raising campaign? Help EarthSky keep going. We need you!


Black bears

Yes, black bears do hibernate. There has been some controversy over whether or not black bears are true hibernators because their body temperature does not drop very low during the winter. However, they do undergo many metabolic changes during the winter that allow them to survive many months without food or water. Hence, several scientists do classify them as hibernators.


Arctic ground squirrel. Image Credit: Kristine Sowl, U.S. Fish and Wildlife Service.

Arctic ground squirrel. Image Credit: Kristine Sowl, U.S. Fish and Wildlife Service.



Arctic ground squirrels

During the onset of cold weather, Arctic ground squirrels dig deep burrows in the ground and hibernate. One scientist attached temperatures sensors to their abdomens and recorded body temperatures in hibernating squirrels as low as -2.9 degrees Celsius (26.8 degrees Fahrenheit), which is below the temperature that water freezes! The squirrel’s blood, however, does not freeze in part because it is salty and also because they have some sort of “super cool” supercooling mechanism that protects them. Scientists are actively researching the brain activity of hibernating Arctic ground squirrels for insights into how to protect people from neurodegenerative diseases like Alzheimer’s and to help them recover from brain injuries. Specifically, the brains of Arctic ground squirrels show a remarkable ability to bounce back after months of dormancy that degrades neuronal connections.


Watercolor painting of the common poorwill by Louise Agassiz Fuertes. Image Credit: Wikimedia Commons.

Watercolor painting of the common poorwill by Louise Agassiz Fuertes. Image Credit: Wikimedia Commons.



Common poorwill

Most birds migrate south when the weather turns cold, but the common poorwill stays put and hibernates. Poorwills are the only bird species known to hibernate. They can be found in the western United States and Canada. Native Americans often referred to this bird as “the sleeping one.”


Torpor is a state of light hibernation that many animals enter into to survive the winter. Animals that use torpor as a survival strategy include raccoons and skunks. While there is no bright line that separates animals that hibernate from those that use torpor, it generally comes down to the length of time that an animal spends in dormancy and the extent to which its body temperature and metabolic rate are depressed. Torpor is associated with brief periods of dormancy, sometimes for only a few hours, and small physiological changes, whereas hibernation is associated with lengthy periods of dormancy and large physiological changes.


Scientists use the term brumation to refer to hibernating-like states in reptiles, which are not warm-blooded animals so the physiological responses are a bit different from those in mammals and birds. Insects enter cold-induced dormant periods too, and this is referred to by the term diapause. Often on the internet, the term hibernation will be used as a catch-all phrase for all of these types of dormant states.


The exact triggers that cause an animal to enter into and emerge from hibernation aren’t well known, but combinations of factors such as changes in temperature, daylight, and food availability are thought to play an important role. Especially critical is an animal’s internal biological clock, which will initiate hormone changes when it is time for the animal to wake up.


Bottom line: Hibernation is a survival strategy that animals use during the winter to conserve energy when food is scarce. Animals that hibernate include bats, black bears, Arctic ground squirrels, and common poorwill birds.


What we didn’t know about hibernating black bears


Spring may come earlier to North American forests


Why does Earth have four seasons?






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Eclipsed moon and sun together this Saturday?


Tonight's sunset and moonrise - September 19, 2013 - as seen by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia. One of the characteristics of the Harvest Moon is that it rises around the time of sunset for several evenings in a row. Thank you, Andy.

This photo does not show an eclipsed moon, but it does show a simultaneous sunset and (nearly) full moonrise as captured by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia in September 2013. On Saturday, April 4, 2015 – from just the right spot on Earth – you might see something like this … but the moon will be in eclipse!



In case you haven’t heard, there’s a total lunar eclipse coming up this Saturday, April 4, 2015. North Americans will see the eclipse Saturday morning. Australians and Asians will see it Saturday evening. Read more about the April 4 eclipse here.


If you’re in just the right spot on Earth, you might observe the eclipsed moon setting while the sun rises – or the eclipsed moon rising while the sun sets. This is called a selenelion. Celestial geometry says this should not happen. After all, in order for an eclipse to take place, the sun and moon must be exactly 180 degrees apart in the sky, in a perfect alignment known as a syzygy. Such perfection – needed for an eclipse to take place – would seem to make it impossible to view the sun and eclipsed moon above your horizon simultaneously.


But – thanks to atmospheric refraction, the same effect that causes a spoon in a glass of water to appear broken in two – you might actually see images of the sun and totally eclipsed moon, both above your horizon at once, lifted up by the effect of refraction.


You need to be positioned in just the right spot on Earth’s surface to see a selenelion. The chart below shows you who has a shot at it for Saturday’s eclipse:


View larger. Note the narrow band on the Earth's surface labeled U3. In North America, This is where the totally eclipsed moon is setting at sunrise on April 4. In Asia, this is where the totally eclipsed moon is rising at sunset April 4. Image credit: Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center.

View larger. Note the narrow band on the Earth’s surface labeled U3. In North America, This is where the totally eclipsed moon is setting at sunrise on April 4. In Asia, this is where the totally eclipsed moon is rising at sunset April 4. If you’re along this line, you might see the totally eclipsed moon and sun together in the sky. Image via Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center.



Have you donated yet in EarthSky’s annual fund-raising campaign? Help EarthSky keep going. We need you!


The eclipse map above is courtesy of the NASA eclipse site. It shows your best chance of witnessing selenelion – a totally eclipsed moon and sun both above the horizon simultaneously – along the very narrow band labeled U3 on the worldwide map above.


However, you still might be able to see a selenelion of a partially eclipsed moon and the sun both above the horizon elsewhere around the world. Given clear skies and an unobstructed horizon, anyplace on the worldwide map between U1 (beginning of partial umbral eclipse) and U4 (end of partial umbral eclipse) might have some chance of seeing a partially eclipsed moon and the sun in the same sky. Click here for a larger view of the worldwide map.


Additionally, click on this handy sunrise/sunset calendar to find out your sunrise/sunset times and moonset/moomrise times. Be sure to to check the moonrise and moonset box.


In North America, it’s along this narrow U3 path where the totally eclipsed moon is setting in the west as the sun is coming up in the east at sunrise April 4 (Louisiana, Arkansas, Missouri, Iowa, Minnesota; and in Canada: Manitoba and the Northwest Territories).


In Asia, the U3 path marks where the totally eclipsed moon is coming up in the east as the sun is sinking in the west at sunset April 4.


Even if you’re along this path, or near it, you’ll want to have your binoculars handy because the eclipsed moon will be contending with the light of day.


Moreover, the short duration of the very shallow total lunar eclipse on April 4 (less than five minutes long! shortest eclipse of this century) might make this selenelion of the totally eclipsed moon and the sun all the harder to observe this time around.


Read more about Saturday’s eclipse – April 4, 2015


Earth's shadow, with full Hunter's Moon, on October 30, 2012. Photo from EarthSky Facebook friend Birgit Boden in northern Sweden.

You might not see the sun and eclipsed moon together, but, if not, here’s something else you can watch for … the eclipsed moon in Earth’s shadow. This photo doe not show an eclipse, but it does show a full moon in Earth’s shadow. Note that Earth’s shadow is a very unusual and deep blue-gray color. If you have a very open horizon, you’ll see that’s it curves downward on either side. Why? Because Earth is a round ball in space. Photo from EarthSky Facebook friend Birgit Boden in northern Sweden.



Bottom line: Who will see a selenelion – the eclipsed moon and sun in the sky simultaneously – for the April 4, 2015 total eclipse of the moon? Charts and info here.






from EarthSky http://ift.tt/1xxR20X

Tonight's sunset and moonrise - September 19, 2013 - as seen by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia. One of the characteristics of the Harvest Moon is that it rises around the time of sunset for several evenings in a row. Thank you, Andy.

This photo does not show an eclipsed moon, but it does show a simultaneous sunset and (nearly) full moonrise as captured by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia in September 2013. On Saturday, April 4, 2015 – from just the right spot on Earth – you might see something like this … but the moon will be in eclipse!



In case you haven’t heard, there’s a total lunar eclipse coming up this Saturday, April 4, 2015. North Americans will see the eclipse Saturday morning. Australians and Asians will see it Saturday evening. Read more about the April 4 eclipse here.


If you’re in just the right spot on Earth, you might observe the eclipsed moon setting while the sun rises – or the eclipsed moon rising while the sun sets. This is called a selenelion. Celestial geometry says this should not happen. After all, in order for an eclipse to take place, the sun and moon must be exactly 180 degrees apart in the sky, in a perfect alignment known as a syzygy. Such perfection – needed for an eclipse to take place – would seem to make it impossible to view the sun and eclipsed moon above your horizon simultaneously.


But – thanks to atmospheric refraction, the same effect that causes a spoon in a glass of water to appear broken in two – you might actually see images of the sun and totally eclipsed moon, both above your horizon at once, lifted up by the effect of refraction.


You need to be positioned in just the right spot on Earth’s surface to see a selenelion. The chart below shows you who has a shot at it for Saturday’s eclipse:


View larger. Note the narrow band on the Earth's surface labeled U3. In North America, This is where the totally eclipsed moon is setting at sunrise on April 4. In Asia, this is where the totally eclipsed moon is rising at sunset April 4. Image credit: Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center.

View larger. Note the narrow band on the Earth’s surface labeled U3. In North America, This is where the totally eclipsed moon is setting at sunrise on April 4. In Asia, this is where the totally eclipsed moon is rising at sunset April 4. If you’re along this line, you might see the totally eclipsed moon and sun together in the sky. Image via Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center.



Have you donated yet in EarthSky’s annual fund-raising campaign? Help EarthSky keep going. We need you!


The eclipse map above is courtesy of the NASA eclipse site. It shows your best chance of witnessing selenelion – a totally eclipsed moon and sun both above the horizon simultaneously – along the very narrow band labeled U3 on the worldwide map above.


However, you still might be able to see a selenelion of a partially eclipsed moon and the sun both above the horizon elsewhere around the world. Given clear skies and an unobstructed horizon, anyplace on the worldwide map between U1 (beginning of partial umbral eclipse) and U4 (end of partial umbral eclipse) might have some chance of seeing a partially eclipsed moon and the sun in the same sky. Click here for a larger view of the worldwide map.


Additionally, click on this handy sunrise/sunset calendar to find out your sunrise/sunset times and moonset/moomrise times. Be sure to to check the moonrise and moonset box.


In North America, it’s along this narrow U3 path where the totally eclipsed moon is setting in the west as the sun is coming up in the east at sunrise April 4 (Louisiana, Arkansas, Missouri, Iowa, Minnesota; and in Canada: Manitoba and the Northwest Territories).


In Asia, the U3 path marks where the totally eclipsed moon is coming up in the east as the sun is sinking in the west at sunset April 4.


Even if you’re along this path, or near it, you’ll want to have your binoculars handy because the eclipsed moon will be contending with the light of day.


Moreover, the short duration of the very shallow total lunar eclipse on April 4 (less than five minutes long! shortest eclipse of this century) might make this selenelion of the totally eclipsed moon and the sun all the harder to observe this time around.


Read more about Saturday’s eclipse – April 4, 2015


Earth's shadow, with full Hunter's Moon, on October 30, 2012. Photo from EarthSky Facebook friend Birgit Boden in northern Sweden.

You might not see the sun and eclipsed moon together, but, if not, here’s something else you can watch for … the eclipsed moon in Earth’s shadow. This photo doe not show an eclipse, but it does show a full moon in Earth’s shadow. Note that Earth’s shadow is a very unusual and deep blue-gray color. If you have a very open horizon, you’ll see that’s it curves downward on either side. Why? Because Earth is a round ball in space. Photo from EarthSky Facebook friend Birgit Boden in northern Sweden.



Bottom line: Who will see a selenelion – the eclipsed moon and sun in the sky simultaneously – for the April 4, 2015 total eclipse of the moon? Charts and info here.






from EarthSky http://ift.tt/1xxR20X

Follow Big Dipper’s arc to Arcturus


Tonight … learn and use the most useful star mnemonic you’ll ever encounter. It’s … follow the arc to Arcturus and drive a spike to Spica.


Scouts learn this phrase. Grandparents teach it to kids. It was one of the first sky tools I learned to use in astronomy. Arcturus and Spica are so bright that you can often see them on a moonlit night – like tonight. Follow the links below to learn more.


Follow the arc to Arcturus.


Drive a spike to Spica.


Only two weeks left in our annual fund-raising campaign! Have you donated yet? Help EarthSky keep going.


Arc to Arcturus

View larger. | Photo taken by Janet Furlong in March, 2013. Thank you Janet! Big Dipper toward the center, the star Arcturus at lower right (in the trees) and the star Polaris at center left.



Follow the arc to Arcturus. Here’s how to locate the star Arcturus, using the Big Dipper as a guide. Find the Big Dipper asterism in the northeastern sky in the evening sky this month, maybe around 9 p.m. It’s very easy to see, a large noticeable dipper-shaped pattern in the northeast in the evening. Once you can see the Big Dipper, notice that it has two parts: a bowl and a handle. Then, with your mind’s eye, draw an imaginary line following the curve in the Dipper’s handle until you come to a bright orange star: follow the arc to Arcturus. Arcturus is the brightest star the constellation Bootes the Herdsman. This star is known in skylore as the Bear Guard.


Arcturus is a giant star with an estimated distance of 37 light-years. It’s special because it’s not moving with the general stream of stars in the flat disk of the Milky Way galaxy. Instead, Arcturus is cutting perpendicularly through the galaxy’s disk at a tremendous rate of speed . . . some 150 kilometers per second.


Millions of years from now this star will be lost from the view of any future inhabitants of Earth, or at least those who are earthbound and looking with the eye alone.


From the western half of North America, the short-lived total lunar eclipse sits low in the west before sunrise on Saturday, April 4. Be sure to find an unobstructed western horizon. Click for an eclipse calculator.

For western North America, the moon will be near the star Spica when it undergoes a total eclipse on Saturday morning, April 4. Read more about the April 4, 2015 eclipse. For Australia and Asia, this eclipse will be visible Saturday evening



Drive a spike to Spica. Once you’ve followed the curve of the Big Dipper’s handle to the star Arcturus, you’re on your way to finding the star Spica. Just extend that same curve on the sky’s dome. You can read more about Spica here.


On springtime evenings in the Northern Hemisphere, extend the handle of the Big Dipper to arc to Arcturus, spike Spica and slide into the constellation Corvus the Crow. We sometimes call this extended arc the spring semicircle.

On springtime evenings in the Northern Hemisphere, extend the handle of the Big Dipper to arc to Arcturus, spike Spica and slide into the constellation Corvus the Crow. We sometimes call this extended arc the spring semicircle.



Bottom line: Use the curve in the handle of the Big Dipper to “follow the arc” to the star Arcturus. Then “drive a spike” to the star Spica. Have fun.


EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store


Donate: Your support means the world to us






from EarthSky http://ift.tt/18G0W4A

Tonight … learn and use the most useful star mnemonic you’ll ever encounter. It’s … follow the arc to Arcturus and drive a spike to Spica.


Scouts learn this phrase. Grandparents teach it to kids. It was one of the first sky tools I learned to use in astronomy. Arcturus and Spica are so bright that you can often see them on a moonlit night – like tonight. Follow the links below to learn more.


Follow the arc to Arcturus.


Drive a spike to Spica.


Only two weeks left in our annual fund-raising campaign! Have you donated yet? Help EarthSky keep going.


Arc to Arcturus

View larger. | Photo taken by Janet Furlong in March, 2013. Thank you Janet! Big Dipper toward the center, the star Arcturus at lower right (in the trees) and the star Polaris at center left.



Follow the arc to Arcturus. Here’s how to locate the star Arcturus, using the Big Dipper as a guide. Find the Big Dipper asterism in the northeastern sky in the evening sky this month, maybe around 9 p.m. It’s very easy to see, a large noticeable dipper-shaped pattern in the northeast in the evening. Once you can see the Big Dipper, notice that it has two parts: a bowl and a handle. Then, with your mind’s eye, draw an imaginary line following the curve in the Dipper’s handle until you come to a bright orange star: follow the arc to Arcturus. Arcturus is the brightest star the constellation Bootes the Herdsman. This star is known in skylore as the Bear Guard.


Arcturus is a giant star with an estimated distance of 37 light-years. It’s special because it’s not moving with the general stream of stars in the flat disk of the Milky Way galaxy. Instead, Arcturus is cutting perpendicularly through the galaxy’s disk at a tremendous rate of speed . . . some 150 kilometers per second.


Millions of years from now this star will be lost from the view of any future inhabitants of Earth, or at least those who are earthbound and looking with the eye alone.


From the western half of North America, the short-lived total lunar eclipse sits low in the west before sunrise on Saturday, April 4. Be sure to find an unobstructed western horizon. Click for an eclipse calculator.

For western North America, the moon will be near the star Spica when it undergoes a total eclipse on Saturday morning, April 4. Read more about the April 4, 2015 eclipse. For Australia and Asia, this eclipse will be visible Saturday evening



Drive a spike to Spica. Once you’ve followed the curve of the Big Dipper’s handle to the star Arcturus, you’re on your way to finding the star Spica. Just extend that same curve on the sky’s dome. You can read more about Spica here.


On springtime evenings in the Northern Hemisphere, extend the handle of the Big Dipper to arc to Arcturus, spike Spica and slide into the constellation Corvus the Crow. We sometimes call this extended arc the spring semicircle.

On springtime evenings in the Northern Hemisphere, extend the handle of the Big Dipper to arc to Arcturus, spike Spica and slide into the constellation Corvus the Crow. We sometimes call this extended arc the spring semicircle.



Bottom line: Use the curve in the handle of the Big Dipper to “follow the arc” to the star Arcturus. Then “drive a spike” to the star Spica. Have fun.


EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store


Donate: Your support means the world to us






from EarthSky http://ift.tt/18G0W4A