Planets, east before dawn

Planets before dawn now, as captured by Niko Powe in Illinois. Thank you, Niko!

The planet action is in the morning sky now, where brilliant Venus and Jupiter and fainter Mars all cluster in the east before sunup. Niko Powe in Illinois captured this image of them on the morning of September 30, 2015. Thank you, Niko!

Click here to read more about October’s planets

October is going to be a fantastic month for planet-watching before dawn. Here’s a preview of what’s to come … May you be blessed with clear skies!

The waning crescent moon will swing by the morning planets Venus, Mars and Jupiter – around October 8, 9 and 10. Read more.

Circle October 10 and 11 on your calendar. That’s when you have the opportunity to view the waning crescent moon and Mercury coupling up in the east before dawn. Read more.

Jupiter will be in conjunction with Mars on October 17. Read more.

A grouping of three planets inside a circle having a 5-degree diameter on the sky’s dome is known as a planetary trio. Venus, Jupiter and Mars will form a planetary trio in the east before dawn from about October 24 to around October 29. Another grouping of three planets won’t happen again until January 10, 2021. Read more.

Bottom line: The brightest planets – Venus and Jupiter – are up before dawn now. Mars is there, too. Mercury will soon join them. During October … wow! They’re going to put on a show.

from EarthSky http://ift.tt/1FIORM5

Planets before dawn now, as captured by Niko Powe in Illinois. Thank you, Niko!

The planet action is in the morning sky now, where brilliant Venus and Jupiter and fainter Mars all cluster in the east before sunup. Niko Powe in Illinois captured this image of them on the morning of September 30, 2015. Thank you, Niko!

Click here to read more about October’s planets

October is going to be a fantastic month for planet-watching before dawn. Here’s a preview of what’s to come … May you be blessed with clear skies!

The waning crescent moon will swing by the morning planets Venus, Mars and Jupiter – around October 8, 9 and 10. Read more.

Circle October 10 and 11 on your calendar. That’s when you have the opportunity to view the waning crescent moon and Mercury coupling up in the east before dawn. Read more.

Jupiter will be in conjunction with Mars on October 17. Read more.

A grouping of three planets inside a circle having a 5-degree diameter on the sky’s dome is known as a planetary trio. Venus, Jupiter and Mars will form a planetary trio in the east before dawn from about October 24 to around October 29. Another grouping of three planets won’t happen again until January 10, 2021. Read more.

Bottom line: The brightest planets – Venus and Jupiter – are up before dawn now. Mars is there, too. Mercury will soon join them. During October … wow! They’re going to put on a show.

from EarthSky http://ift.tt/1FIORM5

The Science Integrity Project and the Statement of Principles for Sound Decision Making in Canada [Confessions of a Science Librarian]

Though not explicitly tied to our current federal election campaign, the début this week of the Science Integrity Project and the publishing of their Statement of Principles for Sound Decision Making in Canada just as the campaign heats up is surely not coincidental.

In any case, election or not, this is a wonderful initiative and I support it wholeheartedly. There’s lots of background on their website about the process for coming up with the principles, an FAQ and a few examples of how the principles work in practice.

From their website:

Welcome to the Science Integrity Project. Our project reflects the collective wisdom of 75 leaders — in science, indigenous knowledge, public policy, civil society, and governance — who are concerned about the erosion of an evidence-based approach to public policy decision-making in Canada.

Why SIP:
The Science Integrity Project was created in response to growing concerns [1] that many public policy decisions made in Canada — and in its cities, provinces and territories — are not consistently supported by solid information derived from the best available evidence — from science and indigenous knowledge.

What is SIP:
Through a series of in-depth interviews and a national forum, we developed principles for improved decision making on the basis of the best available evidence.

We call upon all Canadians, acting individually and collectively, to embrace and apply the principles for evidence-based decision-making. We invite decision makers at all levels to adopt these principles as an enduring standard for public policy development in Canada. We invite scientists, knowledge holders, and research communities to take this commitment a step further by speaking out for science integrity and the use of your research and knowledge in the development of good public policy.

 

There’s a media release that fills in a few more details about the project. And the principles themselves:

Statement Of Principles For Sound Decision-Making In Canada

The Science Integrity Project
There is growing public concern that policy decisions in jurisdictions across Canada are being made without the support of relevant, accurate, and up-to-date information [1]. The Science Integrity Project – a 2-year initiative involving nearly 75 diverse, influential, and experienced thinkers and practitioners nationwide – is an inclusive, constructive, and non-partisan effort aimed at improving the use of evidence in decision making at all levels of government in Canada. The project held a national forum in February 2015 to discuss foundational principles for the generation and use of evidence in decision-making in Canada. This Statement is the product of their work.

The Case For Evidence-Based Decision-Making
Strong public policies, built on the foundations of evidence and analysis, ensure better outcomes for Canadians, increase government accountability and transparency, and improve our democracy. Canadians expect their representatives to seek, consider, and use rigorous, widely sourced evidence to inform decisions. Such evidence may take many forms, including:

• Science in its broadest sense, including the body of knowledge resulting from experiments, systematic observations, statistical data collection and analysis, theory and modeling, and including information from a range of fields in the physical and biological sciences, social sciences, health sciences and engineering; and,
• Indigenous knowledge, the body of knowledge that is the result of intellectual activity and insight gained in a traditional context and adapted over time to modern situations, and which includes the methods, skills, practices, and knowledge contained in codified knowledge systems passed between generations. [2]

Principles for Evidence-based Decision-making
We call upon all Canadians, acting individually and collectively, to embrace and apply the following principles for evidence-based decision-making. These principles are both ambitious and achievable. Real-world applications exist in many Canadian jurisdictions and have been implemented in countries around the world with great success. We believe the robust implementation of these principles will result in a stronger Canada.

Principle 1
The best available evidence – produced by methods that are transparent, rigorous, and conducted with integrity[3] – should always inform decision-making in Canada.

Principle 2
Information should be openly exchanged among scientific researchers, Indigenous knowledge holders, decision makers, and the public[4].

Principle 3
Research results should be preserved, protected, interpreted and shared in a way that is broadly
understandable and accessible.

Principle 4
Decision-making processes, and the manner in which evidence informs them, should be transparent and routinely evaluated.

1. E.g., Professional Institute of the Public Service in Canada (2013) http://ift.tt/1caEFIo; Voices-Voix Coalition (2015) http://ift.tt/1QLxWsJ

2. There are many definitions of indigenous knowledge; we use one adapted from the World Intellectual Property Organization

3. By “integrity” in the use of science and Indigenous knowledge, we mean that public policies are built upon the best available, most relevant knowledge resources and that the transfer and use of knowledge in policy and decision-making is transparent. Integrity in the use of knowledge
in policy-making also requires integrity in the production of knowledge, that is, adhering to professional, ethical, and disciplinary standards in the production of scientific knowledge and codified cultural standards in the production of Indigenous knowledge.

4. Except in rare cases of demonstrated concern regarding privacy and security. For an overview of open access principles see “Concepts of Openness and Open Access” (UNESCO 2015 http://ift.tt/18wfa8C).

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

Though not explicitly tied to our current federal election campaign, the début this week of the Science Integrity Project and the publishing of their Statement of Principles for Sound Decision Making in Canada just as the campaign heats up is surely not coincidental.

In any case, election or not, this is a wonderful initiative and I support it wholeheartedly. There’s lots of background on their website about the process for coming up with the principles, an FAQ and a few examples of how the principles work in practice.

From their website:

Welcome to the Science Integrity Project. Our project reflects the collective wisdom of 75 leaders — in science, indigenous knowledge, public policy, civil society, and governance — who are concerned about the erosion of an evidence-based approach to public policy decision-making in Canada.

Why SIP:
The Science Integrity Project was created in response to growing concerns [1] that many public policy decisions made in Canada — and in its cities, provinces and territories — are not consistently supported by solid information derived from the best available evidence — from science and indigenous knowledge.

What is SIP:
Through a series of in-depth interviews and a national forum, we developed principles for improved decision making on the basis of the best available evidence.

We call upon all Canadians, acting individually and collectively, to embrace and apply the principles for evidence-based decision-making. We invite decision makers at all levels to adopt these principles as an enduring standard for public policy development in Canada. We invite scientists, knowledge holders, and research communities to take this commitment a step further by speaking out for science integrity and the use of your research and knowledge in the development of good public policy.

 

There’s a media release that fills in a few more details about the project. And the principles themselves:

Statement Of Principles For Sound Decision-Making In Canada

The Science Integrity Project
There is growing public concern that policy decisions in jurisdictions across Canada are being made without the support of relevant, accurate, and up-to-date information [1]. The Science Integrity Project – a 2-year initiative involving nearly 75 diverse, influential, and experienced thinkers and practitioners nationwide – is an inclusive, constructive, and non-partisan effort aimed at improving the use of evidence in decision making at all levels of government in Canada. The project held a national forum in February 2015 to discuss foundational principles for the generation and use of evidence in decision-making in Canada. This Statement is the product of their work.

The Case For Evidence-Based Decision-Making
Strong public policies, built on the foundations of evidence and analysis, ensure better outcomes for Canadians, increase government accountability and transparency, and improve our democracy. Canadians expect their representatives to seek, consider, and use rigorous, widely sourced evidence to inform decisions. Such evidence may take many forms, including:

• Science in its broadest sense, including the body of knowledge resulting from experiments, systematic observations, statistical data collection and analysis, theory and modeling, and including information from a range of fields in the physical and biological sciences, social sciences, health sciences and engineering; and,
• Indigenous knowledge, the body of knowledge that is the result of intellectual activity and insight gained in a traditional context and adapted over time to modern situations, and which includes the methods, skills, practices, and knowledge contained in codified knowledge systems passed between generations. [2]

Principles for Evidence-based Decision-making
We call upon all Canadians, acting individually and collectively, to embrace and apply the following principles for evidence-based decision-making. These principles are both ambitious and achievable. Real-world applications exist in many Canadian jurisdictions and have been implemented in countries around the world with great success. We believe the robust implementation of these principles will result in a stronger Canada.

Principle 1
The best available evidence – produced by methods that are transparent, rigorous, and conducted with integrity[3] – should always inform decision-making in Canada.

Principle 2
Information should be openly exchanged among scientific researchers, Indigenous knowledge holders, decision makers, and the public[4].

Principle 3
Research results should be preserved, protected, interpreted and shared in a way that is broadly
understandable and accessible.

Principle 4
Decision-making processes, and the manner in which evidence informs them, should be transparent and routinely evaluated.

1. E.g., Professional Institute of the Public Service in Canada (2013) http://ift.tt/1caEFIo; Voices-Voix Coalition (2015) http://ift.tt/1QLxWsJ

2. There are many definitions of indigenous knowledge; we use one adapted from the World Intellectual Property Organization

3. By “integrity” in the use of science and Indigenous knowledge, we mean that public policies are built upon the best available, most relevant knowledge resources and that the transfer and use of knowledge in policy and decision-making is transparent. Integrity in the use of knowledge
in policy-making also requires integrity in the production of knowledge, that is, adhering to professional, ethical, and disciplinary standards in the production of scientific knowledge and codified cultural standards in the production of Indigenous knowledge.

4. Except in rare cases of demonstrated concern regarding privacy and security. For an overview of open access principles see “Concepts of Openness and Open Access” (UNESCO 2015 http://ift.tt/18wfa8C).

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

Biofluorescent sea turtle [Life Lines]

Check out this neat video from National Geographic’s emerging explorer, David Gruber (a marine biologist at the City University of New York) in which he discusses coming across what he claims is the first observation of biofluorescence in a sea turtle:

Video source:
YouTube

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

Check out this neat video from National Geographic’s emerging explorer, David Gruber (a marine biologist at the City University of New York) in which he discusses coming across what he claims is the first observation of biofluorescence in a sea turtle:

Video source:
YouTube

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

October 2015 guide to the five visible planets

Coming up soon! The bow of the waning crescent moon points toward Venus and Jupiter before sunrise on Wednesday, October 7. Read more

The most noticeable planet this month is dazzling Venus in the east before dawn. Look in the direction of sunrise as dawn begins to light the sky. Next, in that same part of the sky, you’ll notice Jupiter, second-brightest planet. Fainter Mars is also in the morning sky beneath Venus. Saturn is the lone evening planet this month, setting at early evening from mid-northern latitudes and at mid-evening from temperate latitudes in the Southern Hemisphere. Mercury will make a fine appearance in the morning sky for the Northern Hemisphere for a few weeks, centered on mid-October. Follow the links below to learn more about October planets.

Sole evening planet in October 2015

Saturn visible at nightfall and early evening

Morning planets in October 2015

Brilliant Venus in the east before sunrise

Mars between Venus and Jupiter before sunrise

Bright Jupiter below Venus and Mars in morning sky

Mercury at early dawn, better from Northern Hemisphere

Like what EarthSky offers? Sign up for our free daily newsletter today!

Astronomy events, star parties, festivals, workshops for September-December, 2015

The waxing crescent moon helps you to find Saturn after sunset on October 15, October 16 and .

Saturn visible at nightfall and early evening. Throughout October 2015, the golden planet Saturn pops into view at nightfall, though quite low in the southwest sky from mid-northern latitudes. At northerly latitudes, Saturn sets at early evening in early October and at nightfall by the month’s end. At temperate latitudes in the Southern Hemisphere, Saturn sets at mid-to-late evening in early October and early evening in late October.

From all around the world, Saturn is sinking toward the glare of sunset all month long. Saturn will disappear from the evening sky in November 2015 and will reappear in the morning sky in December 2015.

How can you recognize this wonderful planet? It’s golden in color, to the eye. It shines with a steady light. Check the chart above for dates when Saturn will appear near the moon this month. If you can identify Saturn, near the moon, and notice the nearby ruddy star Antares, you’ll be able to spot and identify Saturn and Antares when the moon has moved away.

Binoculars don’t reveal Saturn’s gorgeous rings, by the way. For that, you need a small telescope. But binoculars will enhance Saturn’s golden color and Antares’ reddish complexion.

Saturn’s rings are inclined at about 25^o from edge-on in October 2015, exhibiting their northern face. A few years from now, in October 2017, the rings will open most widely, displaying a maximum inclination of 27^o. As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27^o by May, 2032.

The waning crescent moon swings by the morning planets Venus, Mars, Jupiter and Mercury – in the second week of October. The green line depicts the ecliptic – the pathway of the moon and planets. Read more.

Brilliant Venus in the east before sunrise. Here’s a very fun observation to make this month: Venus before dawn. Venus is the brightest planet and third-brightest sky object overall, after the sun and moon. When it’s visible, it’s very, very prominent in our sky.

Moreover, this dazzling world will enable you to locate the fainter yet relatively nearby planets Mars and Jupiter in the morning sky. Be sure to use the waning crescent moon to locate Venus (plus Mars and Jupiter) in the morning sky on October 7, October 8 and October 9.

You won’t want to miss Venus and the early morning planets, especially in late October. Venus, Mars and Jupiter all meet up in the last week of October to present the closest grouping of three planets until January of 2021. And if you live in the tropics and the Northern Hemisphere, you can also see Mercury below this planetary trio.

Planetary trio lights up morning sky in late October 2015

Jupiter will be in conjunction with Mars on October 17, 2015. If you have trouble seeing Mars in the morning sky, aim them at Jupiter to spot Mars nearby. Mars and Jupiter will share the same binocular field from about October 12 to nearly the end of the month.. Read more.

Mars between Venus and Jupiter before sunrise. Mars is nowhere as bright as the more prominent morning planets, Venus and Jupiter, which rank as the third-brightest and fourth-brightest celestial bodies, respectively, after the sun and moon. Even so, modestly-bright Mars is easily visible in the predawn sky. Simply draw and imaginary line from Venus to Jupiter to locate Mars in between these two brilliant worlds.

Day by day, Jupiter climbs upward toward Mars. Jupiter will finally meet up with Mars for a close-knit conjunction on October 17. After that, Jupiter will continue to climb upward, away from Mars, to have a conjunction with Venus on October 26. This date, October 26, also marks Venus’ greatest morning elongation from the sun, and moreover, features the closest grouping of three planets since May 27, 2013. Another grouping of three planets won’t happen again until January 10, 2021. All three worlds – Venus, Jupiter and Mars – will fit within the same binocular field, so be sure to circle October 26 on your calendar.

Let the waning crescent moon help guide your eye to Mars in the morning sky for several days, centered on or near October 9.

Mars will continue to brighten month by month, until the Red Planet culminates in brightness in May, 2016. Believe it or not, Mars will be more brilliant then than Jupiter is now!

From the Northern Hemisphere, Mercury should be in fine view around mid-month. Draw an imaginary line from Venus through Jupiter to find Mercury near the horizon. Binoculars may be helpful! Read more

Bright Jupiter below Venus and Mars in morning sky. Jupiter starts out the month below Venus and Mars. Keep watching, though, and witness Jupiter’s quick ascent upward, toward Mars and Venus. Jupiter will catch up with Mars on October 17, to exhibit their first conjunction since July 22, 2013. The next conjunction of Mars and Jupiter won’t be forthcoming until until January 7, 2018.

Then Jupiter will head toward Venus, showcasing their third and final conjunction of the year in the morning sky on October 26.

By a wonderful coincidence, as Venus and Jupiter show off their final conjunction of the year – on October 26 – Venus will reach its greatest western (morning) elongation from the sun.

Moreover, the year’s closest grouping of three planets – Venus, Mars and Jupiter – will also take place on October 26. That’s a big deal because the next planetary trio won’t occur again until January, 2021!

The waning crescent moon shines close to Venus for several mornings, centered around October 8.

If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto. In September of 2015, however, Jupiter’s moons will have a hard time competing with the sun’s glare in the morning sky.

These moons circle Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we got to view a number of mutual events involving Jupiter’s moons through a high-powered telescope. Click here or here or here for more details.

Click here for a Jupiter’s moons almanac, courtesy of Sky & Telescope.

Circle October 10 and 11 on your calendar. That’s when you have the opportunity to view the waning crescent moon and Mercury coupling up in the eastern sky at morning dawn. May you be blessed with clear skies! Read more

Mercury at early dawn, better from Northern Hemisphere. Mercury is our solar system’s innermost planet and always stays near the sun in our sky. This planet passed out of the evening sky and into the morning sky on September 30, 2015. From the Northern Hemisphere and southern tropics, you might first see the waning crescent moon near Mercury in the morning sky on October 10 or 11. Mercury will be easier to spot when it’s at its greatest elongation from the sun on October 16.

It’ll be a real challenge to catch Mercury from southerly latitudes, however. This world sits close the the glare of sunrise all month.

For the Northern Hemisphere, October presents Mercury’s best appearance in the morning sky for all 2015. At mid-month, Mercury rises some 90 minutes before sunrise at mid-northern latitudes, and the innermost planet should remain in good view for another week or so after that – or around the time of the Orionid meteor shower.

Look for Mercury over the sunrise point on the horizon as darkness gives way to dawn. Click here for recommended almanacs. They can help you find Mercury’s rising time in your sky, and for the time at which astronomical twilight begins.

Those residing at temperate latitudes in the Southern Hemisphere aren’t as lucky this month. In that part of the world, Mercury – even at its best – rises less than one hour before the sun. From southerly latitudes, the innermost planet will be hard to catch even with binoculars in the glare of dawn. However, binoculars are always recommended to enhance sky views!

Mercury will stay in the morning sky until November 17, 2015. Then it’ll pass into the evening sky, to give both hemispheres a decent evening apparition of Mercury in late December 2015.

Click here for recommended almanacs. They can help you know when Mercury rises in your sky

Eastern sky before dawn now. Photo taken September 18, 2015 and submitted to EarthSky by Greg Hogan in Kathleen, Georgia. Thanks, Greg!

What do we mean by visible planet? By visible planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five visible planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets are visible in our sky because their disks reflect sunlight, and these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. They tend to be bright! You can spot them, and come to know them as faithful friends, if you try.

Bottom line: In October 2015, Saturn is the lone evening planet, appearing in the southwest at nightfall. Venus, Mars and Jupiter convene in the eastern predawn sky, with Mercury joining the morning planets possibly as early as October 10.

View larger. Evening dusk on August 5: Venus at left. Mercury is climbing higher, toward Regulus (at top) and Jupiter (beneath Regulus).

By the evening of July 12, Venus and Jupiter were farther apart and lower in the western sky after sunset. Photo by Robert Kelly. Thanks, Robert!

Photo taken June 13, 2015 by John Nelson at Puget Sound, Washington. Thanks, John!

View larger. | Photo taken in early June, 2015 by Göran Strand in Sweden. He wrote: “One of the last nights during the spring when the stars were still visible … ” Follow Fotograf Göran Strand on Facebook, or @astrofotografen on Instagram. Or visit his website.

View larger.| Venus near the setting sun on November 18, 2014 by Helio de Carvalho Vital in Rio de Janeiro, Brazil. He wrote, “I managed to capture Venus as it is starting its return to dusk, despite the fact that it is still at a mere 6.2° distance from the sun. The photos show it a few minutes before setting behind the northern side of the 1,021-meter high Tijuca Peak, located some 6.5 km away. It was deeply immersed in the intense glare of the sun, that would set some 13 minutes later.”

Lunar eclipse on the night of October 8, 2014. The object to the left is the planet Uranus! This beautiful photo is by Janey Wing Kenyon of Story, Wyoming.

Debra Fryar in Calobreves, Texas captured this photo of the moon and Jupiter on May 31, 2014. Jupiter was close to the twilight then.

With only a modest backyard telescope, you can easily see Jupiter’s four largest moons. Here they are through a 10″ (25 cm) Meade LX200 telescope. Image credit: Jan Sandberg

Jupiter was rivaling the streetlights, when Mohamed Laaifat Photographies captured this photo in Normandy, France. Visit his page on Facebook.

Venus by Danny Crocker-Jensen

These are called star trails. It’s a long-exposure photo, which shows you how Earth is turning under the stars. The brightest object here is Jupiter, which is the second-brightest planet, after Venus. This awesome photo by EarthSky Facebook friend Mohamed Laaifat in Normandy, France. Thank you, Mohamed.

Skywatcher, by Predrag Agatonovic.

Easily locate stars and constellations with EarthSky’s planisphere.

Don’t miss anything. Subscribe to EarthSky News by email

from EarthSky http://ift.tt/IJfHCr

Coming up soon! The bow of the waning crescent moon points toward Venus and Jupiter before sunrise on Wednesday, October 7. Read more

The most noticeable planet this month is dazzling Venus in the east before dawn. Look in the direction of sunrise as dawn begins to light the sky. Next, in that same part of the sky, you’ll notice Jupiter, second-brightest planet. Fainter Mars is also in the morning sky beneath Venus. Saturn is the lone evening planet this month, setting at early evening from mid-northern latitudes and at mid-evening from temperate latitudes in the Southern Hemisphere. Mercury will make a fine appearance in the morning sky for the Northern Hemisphere for a few weeks, centered on mid-October. Follow the links below to learn more about October planets.

Sole evening planet in October 2015

Saturn visible at nightfall and early evening

Morning planets in October 2015

Brilliant Venus in the east before sunrise

Mars between Venus and Jupiter before sunrise

Bright Jupiter below Venus and Mars in morning sky

Mercury at early dawn, better from Northern Hemisphere

Like what EarthSky offers? Sign up for our free daily newsletter today!

Astronomy events, star parties, festivals, workshops for September-December, 2015

The waxing crescent moon helps you to find Saturn after sunset on October 15, October 16 and .

Saturn visible at nightfall and early evening. Throughout October 2015, the golden planet Saturn pops into view at nightfall, though quite low in the southwest sky from mid-northern latitudes. At northerly latitudes, Saturn sets at early evening in early October and at nightfall by the month’s end. At temperate latitudes in the Southern Hemisphere, Saturn sets at mid-to-late evening in early October and early evening in late October.

From all around the world, Saturn is sinking toward the glare of sunset all month long. Saturn will disappear from the evening sky in November 2015 and will reappear in the morning sky in December 2015.

How can you recognize this wonderful planet? It’s golden in color, to the eye. It shines with a steady light. Check the chart above for dates when Saturn will appear near the moon this month. If you can identify Saturn, near the moon, and notice the nearby ruddy star Antares, you’ll be able to spot and identify Saturn and Antares when the moon has moved away.

Binoculars don’t reveal Saturn’s gorgeous rings, by the way. For that, you need a small telescope. But binoculars will enhance Saturn’s golden color and Antares’ reddish complexion.

Saturn’s rings are inclined at about 25^o from edge-on in October 2015, exhibiting their northern face. A few years from now, in October 2017, the rings will open most widely, displaying a maximum inclination of 27^o. As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27^o by May, 2032.

The waning crescent moon swings by the morning planets Venus, Mars, Jupiter and Mercury – in the second week of October. The green line depicts the ecliptic – the pathway of the moon and planets. Read more.

Brilliant Venus in the east before sunrise. Here’s a very fun observation to make this month: Venus before dawn. Venus is the brightest planet and third-brightest sky object overall, after the sun and moon. When it’s visible, it’s very, very prominent in our sky.

Moreover, this dazzling world will enable you to locate the fainter yet relatively nearby planets Mars and Jupiter in the morning sky. Be sure to use the waning crescent moon to locate Venus (plus Mars and Jupiter) in the morning sky on October 7, October 8 and October 9.

You won’t want to miss Venus and the early morning planets, especially in late October. Venus, Mars and Jupiter all meet up in the last week of October to present the closest grouping of three planets until January of 2021. And if you live in the tropics and the Northern Hemisphere, you can also see Mercury below this planetary trio.

Planetary trio lights up morning sky in late October 2015

Jupiter will be in conjunction with Mars on October 17, 2015. If you have trouble seeing Mars in the morning sky, aim them at Jupiter to spot Mars nearby. Mars and Jupiter will share the same binocular field from about October 12 to nearly the end of the month.. Read more.

Mars between Venus and Jupiter before sunrise. Mars is nowhere as bright as the more prominent morning planets, Venus and Jupiter, which rank as the third-brightest and fourth-brightest celestial bodies, respectively, after the sun and moon. Even so, modestly-bright Mars is easily visible in the predawn sky. Simply draw and imaginary line from Venus to Jupiter to locate Mars in between these two brilliant worlds.

Day by day, Jupiter climbs upward toward Mars. Jupiter will finally meet up with Mars for a close-knit conjunction on October 17. After that, Jupiter will continue to climb upward, away from Mars, to have a conjunction with Venus on October 26. This date, October 26, also marks Venus’ greatest morning elongation from the sun, and moreover, features the closest grouping of three planets since May 27, 2013. Another grouping of three planets won’t happen again until January 10, 2021. All three worlds – Venus, Jupiter and Mars – will fit within the same binocular field, so be sure to circle October 26 on your calendar.

Let the waning crescent moon help guide your eye to Mars in the morning sky for several days, centered on or near October 9.

Mars will continue to brighten month by month, until the Red Planet culminates in brightness in May, 2016. Believe it or not, Mars will be more brilliant then than Jupiter is now!

From the Northern Hemisphere, Mercury should be in fine view around mid-month. Draw an imaginary line from Venus through Jupiter to find Mercury near the horizon. Binoculars may be helpful! Read more

Bright Jupiter below Venus and Mars in morning sky. Jupiter starts out the month below Venus and Mars. Keep watching, though, and witness Jupiter’s quick ascent upward, toward Mars and Venus. Jupiter will catch up with Mars on October 17, to exhibit their first conjunction since July 22, 2013. The next conjunction of Mars and Jupiter won’t be forthcoming until until January 7, 2018.

Then Jupiter will head toward Venus, showcasing their third and final conjunction of the year in the morning sky on October 26.

By a wonderful coincidence, as Venus and Jupiter show off their final conjunction of the year – on October 26 – Venus will reach its greatest western (morning) elongation from the sun.

Moreover, the year’s closest grouping of three planets – Venus, Mars and Jupiter – will also take place on October 26. That’s a big deal because the next planetary trio won’t occur again until January, 2021!

The waning crescent moon shines close to Venus for several mornings, centered around October 8.

If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto. In September of 2015, however, Jupiter’s moons will have a hard time competing with the sun’s glare in the morning sky.

These moons circle Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we got to view a number of mutual events involving Jupiter’s moons through a high-powered telescope. Click here or here or here for more details.

Click here for a Jupiter’s moons almanac, courtesy of Sky & Telescope.

Circle October 10 and 11 on your calendar. That’s when you have the opportunity to view the waning crescent moon and Mercury coupling up in the eastern sky at morning dawn. May you be blessed with clear skies! Read more

Mercury at early dawn, better from Northern Hemisphere. Mercury is our solar system’s innermost planet and always stays near the sun in our sky. This planet passed out of the evening sky and into the morning sky on September 30, 2015. From the Northern Hemisphere and southern tropics, you might first see the waning crescent moon near Mercury in the morning sky on October 10 or 11. Mercury will be easier to spot when it’s at its greatest elongation from the sun on October 16.

It’ll be a real challenge to catch Mercury from southerly latitudes, however. This world sits close the the glare of sunrise all month.

For the Northern Hemisphere, October presents Mercury’s best appearance in the morning sky for all 2015. At mid-month, Mercury rises some 90 minutes before sunrise at mid-northern latitudes, and the innermost planet should remain in good view for another week or so after that – or around the time of the Orionid meteor shower.

Look for Mercury over the sunrise point on the horizon as darkness gives way to dawn. Click here for recommended almanacs. They can help you find Mercury’s rising time in your sky, and for the time at which astronomical twilight begins.

Those residing at temperate latitudes in the Southern Hemisphere aren’t as lucky this month. In that part of the world, Mercury – even at its best – rises less than one hour before the sun. From southerly latitudes, the innermost planet will be hard to catch even with binoculars in the glare of dawn. However, binoculars are always recommended to enhance sky views!

Mercury will stay in the morning sky until November 17, 2015. Then it’ll pass into the evening sky, to give both hemispheres a decent evening apparition of Mercury in late December 2015.

Click here for recommended almanacs. They can help you know when Mercury rises in your sky

Eastern sky before dawn now. Photo taken September 18, 2015 and submitted to EarthSky by Greg Hogan in Kathleen, Georgia. Thanks, Greg!

What do we mean by visible planet? By visible planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five visible planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets are visible in our sky because their disks reflect sunlight, and these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. They tend to be bright! You can spot them, and come to know them as faithful friends, if you try.

Bottom line: In October 2015, Saturn is the lone evening planet, appearing in the southwest at nightfall. Venus, Mars and Jupiter convene in the eastern predawn sky, with Mercury joining the morning planets possibly as early as October 10.

View larger. Evening dusk on August 5: Venus at left. Mercury is climbing higher, toward Regulus (at top) and Jupiter (beneath Regulus).

By the evening of July 12, Venus and Jupiter were farther apart and lower in the western sky after sunset. Photo by Robert Kelly. Thanks, Robert!

Photo taken June 13, 2015 by John Nelson at Puget Sound, Washington. Thanks, John!

View larger. | Photo taken in early June, 2015 by Göran Strand in Sweden. He wrote: “One of the last nights during the spring when the stars were still visible … ” Follow Fotograf Göran Strand on Facebook, or @astrofotografen on Instagram. Or visit his website.

View larger.| Venus near the setting sun on November 18, 2014 by Helio de Carvalho Vital in Rio de Janeiro, Brazil. He wrote, “I managed to capture Venus as it is starting its return to dusk, despite the fact that it is still at a mere 6.2° distance from the sun. The photos show it a few minutes before setting behind the northern side of the 1,021-meter high Tijuca Peak, located some 6.5 km away. It was deeply immersed in the intense glare of the sun, that would set some 13 minutes later.”

Lunar eclipse on the night of October 8, 2014. The object to the left is the planet Uranus! This beautiful photo is by Janey Wing Kenyon of Story, Wyoming.

Debra Fryar in Calobreves, Texas captured this photo of the moon and Jupiter on May 31, 2014. Jupiter was close to the twilight then.

With only a modest backyard telescope, you can easily see Jupiter’s four largest moons. Here they are through a 10″ (25 cm) Meade LX200 telescope. Image credit: Jan Sandberg

Jupiter was rivaling the streetlights, when Mohamed Laaifat Photographies captured this photo in Normandy, France. Visit his page on Facebook.

Venus by Danny Crocker-Jensen

These are called star trails. It’s a long-exposure photo, which shows you how Earth is turning under the stars. The brightest object here is Jupiter, which is the second-brightest planet, after Venus. This awesome photo by EarthSky Facebook friend Mohamed Laaifat in Normandy, France. Thank you, Mohamed.

Skywatcher, by Predrag Agatonovic.

Easily locate stars and constellations with EarthSky’s planisphere.

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Sea ice still too thick for Arctic shipping route

New research from York University predicts that it will be decades before the Northwest Passage will be a viable route for regular commercial shipping. Despite climate change, Arctic sea ice remains too thick and treacherous, says the study, published in the journal Geophysical Research Letters on September 25.

The Northwest Passage is a sea route that connects the Atlantic and Pacific Oceans through the Canadian Arctic Archipelago. In the past, the Northwest Passage has been virtually impassable because it was covered by thick, year-round sea ice.

The Northwest Passage. Image credit: geology.com

For commercial shipping, the potential benefits of a clear Northwest Passage are significant. The Northwest Passage is a much shorter route for moving goods between the Pacific and Atlantic regions than the Panama and Suez Canals. Ship routes from Europe to eastern Asia would be 4,000 kilometers (2,500 miles) shorter. Alaskan oil could move quickly by ship to ports in the eastern United States. The vast mineral resources of the Canadian North will be much easier and economical to develop and ship to market.

In the past few years, as the climate has warmed, it’s been speculated that shrinking Arctic sea ice coverage might open the passage for increasing periods of time, to allow regular commercial traffic to pass through the Arctic Ocean via this once impossible route. At the moment, this year’s annual summer minimum Arctic-wide ice coverage is the fourth lowest on record, with similar low coverage in the Northwest Passage, according to information provided by the Canadian Ice Service.

H.M.S. Intrepid, under the command of Irish explorer Sir Francis Leopold McClintock, is trapped in pack ice in Baffin Bay, circa 1853. McClintock is on his first mission to find the 1845 expedition of Sir John Franklin, which disappeared during a search for the Northwest Passage. From a sketch by Commander May R.N. Image credit:Hulton Archive/Getty Images

But the York University researchers say the ice is still too thick for a regular commercial passage to be viable. Next to ice coverage and type, the researchers said, sea ice thickness plays the most important role in assessing shipping hazards and predicting ice break-up.

Lead researcher Christian Haas is professor of geophysics in the Lassonde School of Engineering and Canada Research Chair for Arctic Sea Ice Geophysics. Haas said:

While everyone only looks at ice extent or area, because it is so easy to do with satellites, we study ice thickness, which is important to assess overall changes of ice volume, and helps to understand why and where the ice is most vulnerable to summer melt.

Haas and his team measured first-year and multiyear ice thickness in the Canadian Arctic Archipelago using via airplane. They surveyed the ice in April and May of 2011 and again in 2015. It is considered the first large-scale assessment of ice thickness in the area.

The surveys found a mean thickness of between two and three meters (6.5 to 10 feet) in most regions of the Northwest Passage. Ice originating from the Arctic Ocean showed a mean thickness of more than three meters on average. Some multiyear ice regions contained much thicker, deformed ice that was more than 100 meters (109 yards) wide and more than four meters (13 feet) thick. Haas said:

This is the first-ever such survey in the Northwest Passage, and we were surprised to find this much thick ice in the region in late winter, despite the fact that there is more and more open water in recent years during late summer.

Although the results were obtained in late winter when no ships travel the route, they will help predict how ice break-up and summer ice conditions develop, and help forecast the opening and navigability of the Northwest Passage during summer. It will also affect how sea ice hazards are assessed during the shipping season and provide baseline data going forward.

How climate change will affect the summer ice in the Northwest Passage in the future is difficult to predict, says Haas. Further melting could cause more multiyear ice from the Arctic Ocean to drift into the passage, making it less, not more passable.

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

Bottom line: New research published in the journal Geophysical Research Letters on September 25, 2015 predicts that it will be decades before the Northwest Passage will be a viable route for regular commercial shipping. Despite climate change, Arctic sea ice remains too thick and treacherous, says the study.

Read more from York University

from EarthSky http://ift.tt/1j13Gjh

New research from York University predicts that it will be decades before the Northwest Passage will be a viable route for regular commercial shipping. Despite climate change, Arctic sea ice remains too thick and treacherous, says the study, published in the journal Geophysical Research Letters on September 25.

The Northwest Passage is a sea route that connects the Atlantic and Pacific Oceans through the Canadian Arctic Archipelago. In the past, the Northwest Passage has been virtually impassable because it was covered by thick, year-round sea ice.

The Northwest Passage. Image credit: geology.com

For commercial shipping, the potential benefits of a clear Northwest Passage are significant. The Northwest Passage is a much shorter route for moving goods between the Pacific and Atlantic regions than the Panama and Suez Canals. Ship routes from Europe to eastern Asia would be 4,000 kilometers (2,500 miles) shorter. Alaskan oil could move quickly by ship to ports in the eastern United States. The vast mineral resources of the Canadian North will be much easier and economical to develop and ship to market.

In the past few years, as the climate has warmed, it’s been speculated that shrinking Arctic sea ice coverage might open the passage for increasing periods of time, to allow regular commercial traffic to pass through the Arctic Ocean via this once impossible route. At the moment, this year’s annual summer minimum Arctic-wide ice coverage is the fourth lowest on record, with similar low coverage in the Northwest Passage, according to information provided by the Canadian Ice Service.

H.M.S. Intrepid, under the command of Irish explorer Sir Francis Leopold McClintock, is trapped in pack ice in Baffin Bay, circa 1853. McClintock is on his first mission to find the 1845 expedition of Sir John Franklin, which disappeared during a search for the Northwest Passage. From a sketch by Commander May R.N. Image credit:Hulton Archive/Getty Images

But the York University researchers say the ice is still too thick for a regular commercial passage to be viable. Next to ice coverage and type, the researchers said, sea ice thickness plays the most important role in assessing shipping hazards and predicting ice break-up.

Lead researcher Christian Haas is professor of geophysics in the Lassonde School of Engineering and Canada Research Chair for Arctic Sea Ice Geophysics. Haas said:

While everyone only looks at ice extent or area, because it is so easy to do with satellites, we study ice thickness, which is important to assess overall changes of ice volume, and helps to understand why and where the ice is most vulnerable to summer melt.

Haas and his team measured first-year and multiyear ice thickness in the Canadian Arctic Archipelago using via airplane. They surveyed the ice in April and May of 2011 and again in 2015. It is considered the first large-scale assessment of ice thickness in the area.

The surveys found a mean thickness of between two and three meters (6.5 to 10 feet) in most regions of the Northwest Passage. Ice originating from the Arctic Ocean showed a mean thickness of more than three meters on average. Some multiyear ice regions contained much thicker, deformed ice that was more than 100 meters (109 yards) wide and more than four meters (13 feet) thick. Haas said:

This is the first-ever such survey in the Northwest Passage, and we were surprised to find this much thick ice in the region in late winter, despite the fact that there is more and more open water in recent years during late summer.

Although the results were obtained in late winter when no ships travel the route, they will help predict how ice break-up and summer ice conditions develop, and help forecast the opening and navigability of the Northwest Passage during summer. It will also affect how sea ice hazards are assessed during the shipping season and provide baseline data going forward.

How climate change will affect the summer ice in the Northwest Passage in the future is difficult to predict, says Haas. Further melting could cause more multiyear ice from the Arctic Ocean to drift into the passage, making it less, not more passable.

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

Bottom line: New research published in the journal Geophysical Research Letters on September 25, 2015 predicts that it will be decades before the Northwest Passage will be a viable route for regular commercial shipping. Despite climate change, Arctic sea ice remains too thick and treacherous, says the study.

Read more from York University

from EarthSky http://ift.tt/1j13Gjh

Star of the week: Gamma Cephei, a future North Star

Although Gamma Cephei – also known as Errai – rates as only a third-magnitude or moderately bright star, it is easy to find and quite visible in a dark country sky. To many stargazers, the constellation Cepheus the King looks like a child’s depiction of a house, with Gamma Cephei marking the peak of the roof. This is a fascinating star – a future North Star. It also plays an important role in this history of our understanding of extrasolar planets, that is, planets orbiting distant stars.

How to find Gamma Cephei

Gamma Cephei as a future North Star

Gamma Cephei has the first planet found in a close binary system

Cepheus can be found in the northern sky. It looks very much like a child’s drawing of a house. The star Gamma Cephei, or Errai, marks the peak of the roof of the house.

How to find Gamma Cephei. Do you know the M-shaped or W-shaped constellation Cassiopeia? If so, then draw a line between the star Caph at one end of the M (or W) toward Polaris, our present-day North Star. Gamma Cephei – aka Errai – is just to one side of that line, a bit more than midway along it.

Think of it this way. Cepheus the King is not a particularly prominent constellation, but you’ll know that you’ve found Cepheus, because you’ll see his more striking wife – the M or W-shaped constellation Cassiopeia the Queen – standing at his side.

Or use the familiar Big Dipper asterism to find Gamma Cephei. The two outer stars in the Dipper’s bowl are Merak and Dubhe, sometimes called the Pointers, because a line between them extended northward points to Polaris. Then jump one fist-width – held at arm’s length – beyond Polaris to Gamma Cephei.

For most of the Northern Hemisphere, orange-colored Gamma Cephei shines as a circumpolar star. Circumpolar stars are stars that neither rise nor set, but always appear above the horizon.

The 26,000-year precession cycle causes the north celestial pole to move counter-clockwise in front of the backdrop stars at about one degree every 72 years

Animation showing 26,000-year precession cycle relative to backdrop stars. This cycle causes Earth’s northern axis to point out at an ever-changing succession of North Stars. Image via Wikimedia Commons

Gamma Cephei as a future North Star. Our present North Star, which we know as Polaris, will continue to reign as the northern pole star for centuries to come.

But our present-day Polaris won’t remain the North Star forever, due to a motion of Earth known as the precession of the equinoxes. Gamma Cephei stands next in line to inherit the North Star title. This star will be closer to the north celestial pole than Polaris around 3000 CE. It will most closely mark the north celestial pole around 4000 CE.

But – due to precession – Earth’s northern axis will continue to trace its great circle among the northern stars. Around 7500 CD, Alderamin – Cepheus’ brightest star – will become the North Star. And ultimately, of course, our present-day Polaris will be the North Star once more.

Artist’s conception of Gamma Cephei’s planet, found in 2002, and its view of the two stars in the Gamma Cephei system. The planet, shown here with rings, orbits the bright yellow star on the right every 2.5 years. This was the first planet found in a close binary system. Image and caption via Tim Jones/McDonald Observatory.

Gamma Cephei has the first planet found in a close binary system Gamma Cephei is a binary star – two stars revolving around a common center of mass. One component is an ordinary main-sequence star, somewhat similar to our sun. The other star has less than half our sun’s mass and is considered a red dwarf.

In 2002, astronomers with the McDonald Observatory Planet Search project found a planet for Gamma Cephei. It was the first planet orbiting a star in a close-in binary star system. The discovery had implications for the number of possible planets in our galaxy, because unlike our sun, most stars are in multiple systems. However, planets in multiple systems have their own inherent challenges. For example, some orbits for planets of multiple star systems are not possible for dynamical reasons; a planet would be ejected from the system, or transferred to a more inner or outer orbit.

That said, there are indeed many planets in multiple star systems known today. As of September 28, 2013, a total of 986 planets in 750 planetary systems have been found, including planets in 168 multiple planetary systems. (Source: Exoplanet.eu)

But Gamma Cephei’s planet will always be the first in a close binary!

Bottom line: The star Errai or Gamma Cephei is a binary star system with at least one planet. This star – at the peak of the “roof” in the house-shaped constellation Cepheus the King – will someday be a North Star for Earth.

Polaris: The North Star

from EarthSky http://ift.tt/1eKwLf2

Although Gamma Cephei – also known as Errai – rates as only a third-magnitude or moderately bright star, it is easy to find and quite visible in a dark country sky. To many stargazers, the constellation Cepheus the King looks like a child’s depiction of a house, with Gamma Cephei marking the peak of the roof. This is a fascinating star – a future North Star. It also plays an important role in this history of our understanding of extrasolar planets, that is, planets orbiting distant stars.

How to find Gamma Cephei

Gamma Cephei as a future North Star

Gamma Cephei has the first planet found in a close binary system

Cepheus can be found in the northern sky. It looks very much like a child’s drawing of a house. The star Gamma Cephei, or Errai, marks the peak of the roof of the house.

How to find Gamma Cephei. Do you know the M-shaped or W-shaped constellation Cassiopeia? If so, then draw a line between the star Caph at one end of the M (or W) toward Polaris, our present-day North Star. Gamma Cephei – aka Errai – is just to one side of that line, a bit more than midway along it.

Think of it this way. Cepheus the King is not a particularly prominent constellation, but you’ll know that you’ve found Cepheus, because you’ll see his more striking wife – the M or W-shaped constellation Cassiopeia the Queen – standing at his side.

Or use the familiar Big Dipper asterism to find Gamma Cephei. The two outer stars in the Dipper’s bowl are Merak and Dubhe, sometimes called the Pointers, because a line between them extended northward points to Polaris. Then jump one fist-width – held at arm’s length – beyond Polaris to Gamma Cephei.

For most of the Northern Hemisphere, orange-colored Gamma Cephei shines as a circumpolar star. Circumpolar stars are stars that neither rise nor set, but always appear above the horizon.

The 26,000-year precession cycle causes the north celestial pole to move counter-clockwise in front of the backdrop stars at about one degree every 72 years

Animation showing 26,000-year precession cycle relative to backdrop stars. This cycle causes Earth’s northern axis to point out at an ever-changing succession of North Stars. Image via Wikimedia Commons

Gamma Cephei as a future North Star. Our present North Star, which we know as Polaris, will continue to reign as the northern pole star for centuries to come.

But our present-day Polaris won’t remain the North Star forever, due to a motion of Earth known as the precession of the equinoxes. Gamma Cephei stands next in line to inherit the North Star title. This star will be closer to the north celestial pole than Polaris around 3000 CE. It will most closely mark the north celestial pole around 4000 CE.

But – due to precession – Earth’s northern axis will continue to trace its great circle among the northern stars. Around 7500 CD, Alderamin – Cepheus’ brightest star – will become the North Star. And ultimately, of course, our present-day Polaris will be the North Star once more.

Artist’s conception of Gamma Cephei’s planet, found in 2002, and its view of the two stars in the Gamma Cephei system. The planet, shown here with rings, orbits the bright yellow star on the right every 2.5 years. This was the first planet found in a close binary system. Image and caption via Tim Jones/McDonald Observatory.

Gamma Cephei has the first planet found in a close binary system Gamma Cephei is a binary star – two stars revolving around a common center of mass. One component is an ordinary main-sequence star, somewhat similar to our sun. The other star has less than half our sun’s mass and is considered a red dwarf.

In 2002, astronomers with the McDonald Observatory Planet Search project found a planet for Gamma Cephei. It was the first planet orbiting a star in a close-in binary star system. The discovery had implications for the number of possible planets in our galaxy, because unlike our sun, most stars are in multiple systems. However, planets in multiple systems have their own inherent challenges. For example, some orbits for planets of multiple star systems are not possible for dynamical reasons; a planet would be ejected from the system, or transferred to a more inner or outer orbit.

That said, there are indeed many planets in multiple star systems known today. As of September 28, 2013, a total of 986 planets in 750 planetary systems have been found, including planets in 168 multiple planetary systems. (Source: Exoplanet.eu)

But Gamma Cephei’s planet will always be the first in a close binary!

Bottom line: The star Errai or Gamma Cephei is a binary star system with at least one planet. This star – at the peak of the “roof” in the house-shaped constellation Cepheus the King – will someday be a North Star for Earth.

Polaris: The North Star

from EarthSky http://ift.tt/1eKwLf2

Einstein ring helps weigh a black hole

Highest-resolution observation ever of the gravitational lens system SDP.81, and its Einstein ring. Image via ALMA (NRAO/ESO/NAOJ); B. Saxton NRAO/AUI/NSF

A gravitational lens happens when astronomers on Earth look toward a huge galaxy or galaxy cluster, so massive that its gravity distorts any light passing near. The massive object acts like a lens in space, spreading the light out, often to produce multiple images of a more distant object that happens to be shining behind it. Or, if the distant background object and the intervening massive galaxy are perfectly aligned, the gravitational lens may spread the light to produce an image of a ring in space.

A ring-shaped image produced in this way is known as an Einstein Ring. The ring itself not a real physical structure in space, but just a play of light and gravity, a result of the gravitational lensing effect. And yet these Einstein rings have revealed some of the mysteries of the cosmos to the astronomers who study them.

Astronomers in Asia recently analyzed the clearest-ever images of a gravitational lens called SDP.81. They carefully studied the Einstein Ring produced by this system, in order to calculate that a supermassive black hole located near the center of SDP.81 – the lensing galaxy – may contain over 300 million times the mass of our sun.

In other words, the gravitational lens and its resulting Einstein ring let them weigh a black hole. The Astrophysical Journal published their results on on September 28, 2015.

Astronomers determined that the foreground galaxy in the SDP.81 system, whose mass is lensing the background source into the Einstein Ring, contains a supermassive black hole with more than 300 million solar masses. Image via ALMA (NRAO/ESO/NAOJ)/ Kenneth Wong (ASIAA).

The team also said that there are just two galaxies in this Einstein Ring system. The massive foreground galaxy – the object doing the lensing – is 4 billion light years away. And the background galaxy is 12 billion light-years away. The gravity of the massive foreground galaxy acts on the light from the background galaxy to create the ring structure.

The background galaxy contains a large amount of dust that has been heated by vigorous star formation, causing it to shine brightly in submillimeter light.

These astronomers used a telescope sensitive to this form of light – the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile – to acquire the images.

The left panel shows the foreground lensing galaxy (observed with Hubble), and the gravitational lens system SDP.81, which forms an almost perfect Einstein Ring but is hardly visible. The middle image shows the sharp ALMA image of the Einstein Ring. The foreground lensing galaxy is invisible to ALMA, as it does not emit strong submillimeter-wavelength light. The resulting reconstructed image of the distant galaxy (right) using sophisticated models of the magnifying gravitational lens reveals fine structures within the ring that have never been seen before: several giant clouds of dust and cold molecular gas, which are the birthplaces of stars and planets. Image via ALMA (NRAO/ESO/NAOJ)/Y. Tamura (The University of Tokyo)/Mark Swinbank (Durham University).

Three astronomers at the Institute of Astronomy and Astrophysics (ASIAA), headquartered at on the campus of National Taiwan University, conducted this research study. They are postdoctoral fellow Kenneth Wong, assistant research fellow Sherry Suyu and associate research fellow Satoki Matsushita.

They “weighed” the massive foreground lensing galaxy itself and found that it contains over 350 billion times the mass of our sun. Their statement explained:

Wong, together with Suyu and Matsushita, analyzed the central regions of SDP.81 and found the predicted central image of the background galaxy to be extremely faint. Lensing theory predicts that the central image of a lensing system is very sensitive to the mass of a [central] supermassive black hole in the lens galaxy:­­ the more massive the black hole, the fainter the central image.

From this, they calculated that the supermassive black hole, located very close to the center of the SDP.81, may contain over 300 million times the mass of the sun.

The first author of the article, Dr. Kenneth Wong, explained [that] almost all massive galaxies seem to have supermassive black holes at their centers:

‘They can be millions, or even billions of times more massive than the sun. However, we can only directly calculate the mass for very nearby galaxies. With ALMA, we now have the sensitivity to look for the central image of the lens, which can allow us to determine the mass of much more distant black holes.

These astronomers said that measuring the masses of more distant black holes is the key to understanding their relationship with their host galaxies and how they grow over time.

View larger. | Ignore the distances on this diagram (it’s from a different source) and just notice how a gravitational lens works. Image via Herschel ATLAS Gravitational Lenses.

Bottom line: Astronomers can directly “weigh” only the nearest supermassive black holes in galaxy centers. Using a gravitational lens, and an Einstein ring, they now weighed a black hole at the center of galaxy located 12 billion light-years away.

Via ASIAA

from EarthSky http://ift.tt/1Vnf8Xv

Highest-resolution observation ever of the gravitational lens system SDP.81, and its Einstein ring. Image via ALMA (NRAO/ESO/NAOJ); B. Saxton NRAO/AUI/NSF

A gravitational lens happens when astronomers on Earth look toward a huge galaxy or galaxy cluster, so massive that its gravity distorts any light passing near. The massive object acts like a lens in space, spreading the light out, often to produce multiple images of a more distant object that happens to be shining behind it. Or, if the distant background object and the intervening massive galaxy are perfectly aligned, the gravitational lens may spread the light to produce an image of a ring in space.

A ring-shaped image produced in this way is known as an Einstein Ring. The ring itself not a real physical structure in space, but just a play of light and gravity, a result of the gravitational lensing effect. And yet these Einstein rings have revealed some of the mysteries of the cosmos to the astronomers who study them.

Astronomers in Asia recently analyzed the clearest-ever images of a gravitational lens called SDP.81. They carefully studied the Einstein Ring produced by this system, in order to calculate that a supermassive black hole located near the center of SDP.81 – the lensing galaxy – may contain over 300 million times the mass of our sun.

In other words, the gravitational lens and its resulting Einstein ring let them weigh a black hole. The Astrophysical Journal published their results on on September 28, 2015.

Astronomers determined that the foreground galaxy in the SDP.81 system, whose mass is lensing the background source into the Einstein Ring, contains a supermassive black hole with more than 300 million solar masses. Image via ALMA (NRAO/ESO/NAOJ)/ Kenneth Wong (ASIAA).

The team also said that there are just two galaxies in this Einstein Ring system. The massive foreground galaxy – the object doing the lensing – is 4 billion light years away. And the background galaxy is 12 billion light-years away. The gravity of the massive foreground galaxy acts on the light from the background galaxy to create the ring structure.

The background galaxy contains a large amount of dust that has been heated by vigorous star formation, causing it to shine brightly in submillimeter light.

These astronomers used a telescope sensitive to this form of light – the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile – to acquire the images.

The left panel shows the foreground lensing galaxy (observed with Hubble), and the gravitational lens system SDP.81, which forms an almost perfect Einstein Ring but is hardly visible. The middle image shows the sharp ALMA image of the Einstein Ring. The foreground lensing galaxy is invisible to ALMA, as it does not emit strong submillimeter-wavelength light. The resulting reconstructed image of the distant galaxy (right) using sophisticated models of the magnifying gravitational lens reveals fine structures within the ring that have never been seen before: several giant clouds of dust and cold molecular gas, which are the birthplaces of stars and planets. Image via ALMA (NRAO/ESO/NAOJ)/Y. Tamura (The University of Tokyo)/Mark Swinbank (Durham University).

Three astronomers at the Institute of Astronomy and Astrophysics (ASIAA), headquartered at on the campus of National Taiwan University, conducted this research study. They are postdoctoral fellow Kenneth Wong, assistant research fellow Sherry Suyu and associate research fellow Satoki Matsushita.

They “weighed” the massive foreground lensing galaxy itself and found that it contains over 350 billion times the mass of our sun. Their statement explained:

Wong, together with Suyu and Matsushita, analyzed the central regions of SDP.81 and found the predicted central image of the background galaxy to be extremely faint. Lensing theory predicts that the central image of a lensing system is very sensitive to the mass of a [central] supermassive black hole in the lens galaxy:­­ the more massive the black hole, the fainter the central image.

From this, they calculated that the supermassive black hole, located very close to the center of the SDP.81, may contain over 300 million times the mass of the sun.

The first author of the article, Dr. Kenneth Wong, explained [that] almost all massive galaxies seem to have supermassive black holes at their centers:

‘They can be millions, or even billions of times more massive than the sun. However, we can only directly calculate the mass for very nearby galaxies. With ALMA, we now have the sensitivity to look for the central image of the lens, which can allow us to determine the mass of much more distant black holes.

These astronomers said that measuring the masses of more distant black holes is the key to understanding their relationship with their host galaxies and how they grow over time.

View larger. | Ignore the distances on this diagram (it’s from a different source) and just notice how a gravitational lens works. Image via Herschel ATLAS Gravitational Lenses.

Bottom line: Astronomers can directly “weigh” only the nearest supermassive black holes in galaxy centers. Using a gravitational lens, and an Einstein ring, they now weighed a black hole at the center of galaxy located 12 billion light-years away.

Via ASIAA

from EarthSky http://ift.tt/1Vnf8Xv