It’s been a busy few weeks. I hosted a Passover seder. (What? Atheists can’t have seders?) Actually, I run a pretty laid back seder, all the more so this year considering there were goyim in attendance. It’s mostly just a big dinner with some Hebrew and matzoh and charoset thrown in for fun. But if I go a year without doing the four questions then I go through withdrawal, so a seder it is. My parents drove down from New Jersey for the big event, and since I can’t let them see the squalor I actually live in this meant a fair amount of cleaning. It’s good that they visit from time to time, since I need the incentive.
On top of that, the semester entered its dramatic final week. We still have finals to get through, but regular classes are now done. Yay!
But I’ve plainly been neglecting the blog again, so how about a new Sunday Chess Problem? I’ve chosen an easy to digest morsel for you, once again from Milan Vukcevich. The diagram below calls for Helpmate in Two:
We have not featured a helpmate in a while, so let me remind you how this works. In a helpmate, black and white cooperate to produce a position in which black is mated. Black always moves first! So, in a helpmate in two, we seek a sequence that goes 1. Black moves, white moves; 2. Black moves, white gives mate.
Now, in a short helpmate like this one, it is generally impossible to pack enough strategy into a single solution to make things interesting. With white and black working together, it is just too easy to contrive a mate. For that reason, short helpmates will generally have multiple solutions. This one, as it happens, has four solutions. For the problem to be interesting the solutions should be thematically related in some way.
Let’s have a look at the diagram. Since white essentially has only the two rooks with which to work, we might suspect the classic two rooks mate. You know the one I mean. The black king is trapped on the edge of the board, with the rooks occupying adjacent files to give mate. In the diagram we could try to contrive this mate either on the first and second ranks, or on the g and h files. As it happens, two of the solutions execute the first approach, while two of the solutions execute the second.
There are certainly some obstacles to overcome in giving these mates. Regardless of which of the two mating patterns we pursue, the white rook on b6 is obstructed by one of his pawns. The black rook, bishop and queen are all poised to interpose. And the white rook on g2 must move to somewhere safe, since currently he can be taken by the black king.
Can white and black, working together, overcome all these problems in a mere two moves? Yes he can!
Beyond that, the solutions pretty much speak for themselves. Just pay attention to all the line-openings, shut-offs, and interferences. Here we go. The first solution is this: 1. Rxb4 Rd2 2. Re4 Rb1 mate.
Next up is: 1. Nxb4 Rc2 2. Nd5 Rb1 mate.
Now we try to contrive mate on the g and h files. Here’s the first way: 1. Nxg6 Rg4 2. Ne7 Rh6 mate.
And finally we have this: 1. Bxg6 Rg5 2. Be4 Rh6 mate.
That was a lot of fun! Helpmates can sometimes seem like the candy of the chess problem world, though. Very enjoyable, and they certainly give you a brief thrill, but perhaps they are not as nourishing as those intricate, strategical, direct mates.
See you next week!
from ScienceBlogs http://ift.tt/1SHNH4a
It’s been a busy few weeks. I hosted a Passover seder. (What? Atheists can’t have seders?) Actually, I run a pretty laid back seder, all the more so this year considering there were goyim in attendance. It’s mostly just a big dinner with some Hebrew and matzoh and charoset thrown in for fun. But if I go a year without doing the four questions then I go through withdrawal, so a seder it is. My parents drove down from New Jersey for the big event, and since I can’t let them see the squalor I actually live in this meant a fair amount of cleaning. It’s good that they visit from time to time, since I need the incentive.
On top of that, the semester entered its dramatic final week. We still have finals to get through, but regular classes are now done. Yay!
But I’ve plainly been neglecting the blog again, so how about a new Sunday Chess Problem? I’ve chosen an easy to digest morsel for you, once again from Milan Vukcevich. The diagram below calls for Helpmate in Two:
We have not featured a helpmate in a while, so let me remind you how this works. In a helpmate, black and white cooperate to produce a position in which black is mated. Black always moves first! So, in a helpmate in two, we seek a sequence that goes 1. Black moves, white moves; 2. Black moves, white gives mate.
Now, in a short helpmate like this one, it is generally impossible to pack enough strategy into a single solution to make things interesting. With white and black working together, it is just too easy to contrive a mate. For that reason, short helpmates will generally have multiple solutions. This one, as it happens, has four solutions. For the problem to be interesting the solutions should be thematically related in some way.
Let’s have a look at the diagram. Since white essentially has only the two rooks with which to work, we might suspect the classic two rooks mate. You know the one I mean. The black king is trapped on the edge of the board, with the rooks occupying adjacent files to give mate. In the diagram we could try to contrive this mate either on the first and second ranks, or on the g and h files. As it happens, two of the solutions execute the first approach, while two of the solutions execute the second.
There are certainly some obstacles to overcome in giving these mates. Regardless of which of the two mating patterns we pursue, the white rook on b6 is obstructed by one of his pawns. The black rook, bishop and queen are all poised to interpose. And the white rook on g2 must move to somewhere safe, since currently he can be taken by the black king.
Can white and black, working together, overcome all these problems in a mere two moves? Yes he can!
Beyond that, the solutions pretty much speak for themselves. Just pay attention to all the line-openings, shut-offs, and interferences. Here we go. The first solution is this: 1. Rxb4 Rd2 2. Re4 Rb1 mate.
Next up is: 1. Nxb4 Rc2 2. Nd5 Rb1 mate.
Now we try to contrive mate on the g and h files. Here’s the first way: 1. Nxg6 Rg4 2. Ne7 Rh6 mate.
And finally we have this: 1. Bxg6 Rg5 2. Be4 Rh6 mate.
That was a lot of fun! Helpmates can sometimes seem like the candy of the chess problem world, though. Very enjoyable, and they certainly give you a brief thrill, but perhaps they are not as nourishing as those intricate, strategical, direct mates.
On May 22, 2016, Earth will fly between Mars and the sun, bringing the red planet closer to Earth than it’s been for over a decade. Astronomers call this event an opposition of Mars, and, although Mars’ oppositions typically come every other year, some bring Mars especially close. At this 2016 opposition, Mars isn’t as close as it can be. We’ll have to wait until 2018 for that. But, at a distance of 46.78 million miles (75.28 million km), this opposition brings Mars closer than it has been since the Martian opposition of November 7, 2005. As a result, for some weeks around late May, Mars will appear very bright! Follow the links below to learn more about Mars at its amazing 2016 opposition:
View larger | Mikhail Chubarets in the Ukraine made this chart. It shows the view of Mars through a telescope in 2016. We pass between Mars and the sun on May 22. We won’t see Mars as a disk like this with the eye alone. But, between the start of 2016 and May, the dot of light that is Mars will grow dramatically brighter and redder in our night sky. Watch for it!
What is an opposition? All superior planets – that is, planets orbiting the sun outside Earth’s orbit – are said to be at opposition whenever the Earth passes in between that planet and the sun, in our smaller and faster orbit.
The superior planets that are easily visible to the unaided eye include Mars, Jupiter and Saturn. Uranus and Neptune are also superior planets.
Mars is the next planet outward from Earth, at a mean distance from the sun of just over 1.5 astronomical units (AU). One AU equals one Earth-sun distance.
For comparison, the superior planets Jupiter and Saturn reside at a distance of about 5.2 AU and 9.6 AU.
Earth passes between the sun and Mars in a mean period of two years and 49 days, though the time period between successive oppositions is actually quite variable. An opposition can come anywhere from two years and one month – up to two years and two and one-half months – after the prior one.
At all oppositions of Mars (or any superior planet), the planet shines at its brightest in our sky and rises when the sun sets. It’s opposite the sun, as we swing between it and the sun. Mars at opposition stays out all night long, from sundown to sunup. It climbs highest up for the night at midnight.
Diagram by Roy L. Bishop. Copyright Royal Astronomical Society of Canada. Used with permission. Visit the RASC estore to purchase the Observers Handbook, a necessary tool for all skywatchers. Read more about this image.
Why are Mars’ oppositions so variable? Earth’s orbit around the sun is very nearly circular. But Mars has a much more eccentric (oblong) orbit, which brings the red planet some 43 million kilometers (26 million miles) farther from the sun at its farthest point (aphelion) than at its closest point (perihelion).
That’s why the distance of Mars at opposition varies so widely. Earth flies between Mars and the sun every two years; sometimes that happens when Mars is far from the sun in its orbit, and sometimes it happens when Mars is close. The cycle of close and far Mars oppositions is about 15 years long. More about that below, or examine the chart above.
You might see that a Mars opposition coinciding with perihelion (the planet’s closest point to the sun) will be much more magnificent than a Mars’ opposition at aphelion (farthest point from the sun).
Astronomers call a Mars opposition coinciding with Mars’ closest point to the sun a perihelic opposition.
For example, the angular size of Mars’ disk during a perihelic opposition is nearly twice as large, and the brightness of Mars is nearly five times as great, than at an aphelic opposition.
Mars, Saturn, star Antares and moon on March 29, 2016 from Tom Wildoner in Weatherly, Pennsylvania. The two planets and bright star make a recognizable triangle on our sky’s dome throughout the opposition months.
Or let the moon guide you to Mars. Look for the Blue Moon to pair up with Mars on the sky’s dome on May 21. The green line depicts the ecliptic – sun’s path across our sky.
How to see Mars near its 2016 opposition. This year, we’re doubly lucky, when it comes to Mars. The planet is having a close opposition. And it’s visible on our sky’s dome within a noticeable pattern – a triangle – with Mars, Saturn and the bright star Antares marking the corners.
Mars shines near the planet Saturn and Antares, the brightest star in the constellation Scorpius the Scorpion, not just at opposition, but for many months in 2016.
You’ll enjoy picking this triangle out on the sky’s dome now, and comparing the brightness of Mars to that of Saturn and Antares in the coming months. On its opposition date on May 22, Mars shines some 7 times more brilliantly than Saturn, and some 17 times more brilliantly than the red star Antares.
Incidentally, the name Antares means like Mars. The ancients probably gave it that name because of the similarity of color between this star and the red planet. Notice the two objects’ colors. And notice how much the star twinkles while the planet Mars shines steadily. If you’ve never been able notice the steady light of planets, Mars and Antares can help!
Be sure to let the moon guide you to Mars, Saturn and Antares for several nights, centered on May 21. See the chart above.
After opposition, Mars will start to decrease in brightness, fading to Saturn’s magnitude by November, 2016, and then to Antares’ magnitude in January, 2017. But you can see that Northern Hemisphere summer (Southern Hemisphere winter) in 2016 will be an awesome time to amaze your family and friends by pointing Mars out in the night sky.
In 2016, Mars will briefly match the brightness of Jupiter, currently the brightest starlike object in the evening sky (since Venus is now behind the sun).
By the way, Mars has a much greater swing in brightness than do the planets Jupiter and Saturn. On rare occasions, Mars can (briefly) outshine Jupiter in the night sky during a favorable opposition. Meanwhile, in a non-opposition year, the red planet remains rather inconspicuous, blending in with nighttime’s numerous modestly-bright stars.
For instance, one year after the May 22, 2016 opposition, Mars will be some 5 times farther from Earth and some 30 times fainter.
In the year 2017, Mars will fade into a faint ember of its once-fiery self at opposition.
The inner dark circle represents Earth’s orbit around the sun; the outer dark circle represents Mars’ orbit. When Mars is near the sun, as it was in 2003, we have an extra-close opposition. On the other hand, 2012 was a particularly distant opposition of Mars because Mars was far from the sun in its orbit. At the 2014 opposition, Mars is getting closer to the sun again and therefore it’ll be closer to us than it was in 2012. But it’s not as close at this opposition as it will be in 2018. Diagram via Sydney Observatory.
Close Mars oppositions recur in cycles
The greatest/closest opposition of Mars since Stone Age times happened on August 28, 2003 (55.76 million kilometers or 34.65 miles). Close oppositions repeat in cycles of 15 to 17 years, so the oppositions of 2018 and 2020 will feature respectably close encounters – though neither will match the record-breaking opposition of August, 2003.
Similarly great Martian oppositions recur in cycles of 79 and 284 years. Seventy-nine years after the 2003 opposition, the opposition on September 1, 2082, will present Mars only a hair’s-breadth more distant than it was during the super-close opposition of August 28, 2003. Then 284 years after the 2003 opposition, a new record for closeness will accompany the August 29, 2287 opposition (55.69 million kilometers or 34.60 million miles).
Then 363 years (284 years + 79 years = 363 years) after the record-setting August 29, 2287 opposition, the opposition of September 4, 2650, will break that milestone to set another new record (55.65 million kilometers or 34.58 million miles).
Hubble Site contrasts the very distant opposition on February 12, 1995 (101.08 million kilometers) with the super-close opposition of August 28, 2003 (55.76 million kilometers). Image via Hubblesite
Distant Mars oppositions recur in cycles, too. Surprised? Of course, you aren’t. Cycles abound in outer space.
A particularly small or distant opposition of Mars will happen on February 19, 2027 (101.42 million kilometers or 63.02 million miles). Distant oppositions recur in periods of 15 to 17 years, so the years 2042 and 2044 will feature small oppositions, as well.
Neither Mars opposition will be as distant as the 2027 one, however.
Similarly distant oppositions recur in periods of 79 and 284 years. But we don’t find a more distant opposition than the one occurring in the year 2027 until 442 years later (284 years + 79 years + 79 years = 442 years), on February 27, 2469. At that time, the red planet will be a whopping 101.46 million kilometers (63.04 million miles) from Earth.
Telescopic image of Mars. During a close opposition, like the one in 2016, observers will make out more features on the planets surface. We won’t see Mars this size again until 2018, when Mars will put on an even better show. Illustration via nasa.tumblr.com.
Bottom line: This year, in 2016, enjoy the favorable opposition of May 22, as the red planet Mars shines in close vicinity of the planet Saturn and the red star Antares.
from EarthSky http://ift.tt/24gpFYS
On May 22, 2016, Earth will fly between Mars and the sun, bringing the red planet closer to Earth than it’s been for over a decade. Astronomers call this event an opposition of Mars, and, although Mars’ oppositions typically come every other year, some bring Mars especially close. At this 2016 opposition, Mars isn’t as close as it can be. We’ll have to wait until 2018 for that. But, at a distance of 46.78 million miles (75.28 million km), this opposition brings Mars closer than it has been since the Martian opposition of November 7, 2005. As a result, for some weeks around late May, Mars will appear very bright! Follow the links below to learn more about Mars at its amazing 2016 opposition:
View larger | Mikhail Chubarets in the Ukraine made this chart. It shows the view of Mars through a telescope in 2016. We pass between Mars and the sun on May 22. We won’t see Mars as a disk like this with the eye alone. But, between the start of 2016 and May, the dot of light that is Mars will grow dramatically brighter and redder in our night sky. Watch for it!
What is an opposition? All superior planets – that is, planets orbiting the sun outside Earth’s orbit – are said to be at opposition whenever the Earth passes in between that planet and the sun, in our smaller and faster orbit.
The superior planets that are easily visible to the unaided eye include Mars, Jupiter and Saturn. Uranus and Neptune are also superior planets.
Mars is the next planet outward from Earth, at a mean distance from the sun of just over 1.5 astronomical units (AU). One AU equals one Earth-sun distance.
For comparison, the superior planets Jupiter and Saturn reside at a distance of about 5.2 AU and 9.6 AU.
Earth passes between the sun and Mars in a mean period of two years and 49 days, though the time period between successive oppositions is actually quite variable. An opposition can come anywhere from two years and one month – up to two years and two and one-half months – after the prior one.
At all oppositions of Mars (or any superior planet), the planet shines at its brightest in our sky and rises when the sun sets. It’s opposite the sun, as we swing between it and the sun. Mars at opposition stays out all night long, from sundown to sunup. It climbs highest up for the night at midnight.
Diagram by Roy L. Bishop. Copyright Royal Astronomical Society of Canada. Used with permission. Visit the RASC estore to purchase the Observers Handbook, a necessary tool for all skywatchers. Read more about this image.
Why are Mars’ oppositions so variable? Earth’s orbit around the sun is very nearly circular. But Mars has a much more eccentric (oblong) orbit, which brings the red planet some 43 million kilometers (26 million miles) farther from the sun at its farthest point (aphelion) than at its closest point (perihelion).
That’s why the distance of Mars at opposition varies so widely. Earth flies between Mars and the sun every two years; sometimes that happens when Mars is far from the sun in its orbit, and sometimes it happens when Mars is close. The cycle of close and far Mars oppositions is about 15 years long. More about that below, or examine the chart above.
You might see that a Mars opposition coinciding with perihelion (the planet’s closest point to the sun) will be much more magnificent than a Mars’ opposition at aphelion (farthest point from the sun).
Astronomers call a Mars opposition coinciding with Mars’ closest point to the sun a perihelic opposition.
For example, the angular size of Mars’ disk during a perihelic opposition is nearly twice as large, and the brightness of Mars is nearly five times as great, than at an aphelic opposition.
Mars, Saturn, star Antares and moon on March 29, 2016 from Tom Wildoner in Weatherly, Pennsylvania. The two planets and bright star make a recognizable triangle on our sky’s dome throughout the opposition months.
Or let the moon guide you to Mars. Look for the Blue Moon to pair up with Mars on the sky’s dome on May 21. The green line depicts the ecliptic – sun’s path across our sky.
How to see Mars near its 2016 opposition. This year, we’re doubly lucky, when it comes to Mars. The planet is having a close opposition. And it’s visible on our sky’s dome within a noticeable pattern – a triangle – with Mars, Saturn and the bright star Antares marking the corners.
Mars shines near the planet Saturn and Antares, the brightest star in the constellation Scorpius the Scorpion, not just at opposition, but for many months in 2016.
You’ll enjoy picking this triangle out on the sky’s dome now, and comparing the brightness of Mars to that of Saturn and Antares in the coming months. On its opposition date on May 22, Mars shines some 7 times more brilliantly than Saturn, and some 17 times more brilliantly than the red star Antares.
Incidentally, the name Antares means like Mars. The ancients probably gave it that name because of the similarity of color between this star and the red planet. Notice the two objects’ colors. And notice how much the star twinkles while the planet Mars shines steadily. If you’ve never been able notice the steady light of planets, Mars and Antares can help!
Be sure to let the moon guide you to Mars, Saturn and Antares for several nights, centered on May 21. See the chart above.
After opposition, Mars will start to decrease in brightness, fading to Saturn’s magnitude by November, 2016, and then to Antares’ magnitude in January, 2017. But you can see that Northern Hemisphere summer (Southern Hemisphere winter) in 2016 will be an awesome time to amaze your family and friends by pointing Mars out in the night sky.
In 2016, Mars will briefly match the brightness of Jupiter, currently the brightest starlike object in the evening sky (since Venus is now behind the sun).
By the way, Mars has a much greater swing in brightness than do the planets Jupiter and Saturn. On rare occasions, Mars can (briefly) outshine Jupiter in the night sky during a favorable opposition. Meanwhile, in a non-opposition year, the red planet remains rather inconspicuous, blending in with nighttime’s numerous modestly-bright stars.
For instance, one year after the May 22, 2016 opposition, Mars will be some 5 times farther from Earth and some 30 times fainter.
In the year 2017, Mars will fade into a faint ember of its once-fiery self at opposition.
The inner dark circle represents Earth’s orbit around the sun; the outer dark circle represents Mars’ orbit. When Mars is near the sun, as it was in 2003, we have an extra-close opposition. On the other hand, 2012 was a particularly distant opposition of Mars because Mars was far from the sun in its orbit. At the 2014 opposition, Mars is getting closer to the sun again and therefore it’ll be closer to us than it was in 2012. But it’s not as close at this opposition as it will be in 2018. Diagram via Sydney Observatory.
Close Mars oppositions recur in cycles
The greatest/closest opposition of Mars since Stone Age times happened on August 28, 2003 (55.76 million kilometers or 34.65 miles). Close oppositions repeat in cycles of 15 to 17 years, so the oppositions of 2018 and 2020 will feature respectably close encounters – though neither will match the record-breaking opposition of August, 2003.
Similarly great Martian oppositions recur in cycles of 79 and 284 years. Seventy-nine years after the 2003 opposition, the opposition on September 1, 2082, will present Mars only a hair’s-breadth more distant than it was during the super-close opposition of August 28, 2003. Then 284 years after the 2003 opposition, a new record for closeness will accompany the August 29, 2287 opposition (55.69 million kilometers or 34.60 million miles).
Then 363 years (284 years + 79 years = 363 years) after the record-setting August 29, 2287 opposition, the opposition of September 4, 2650, will break that milestone to set another new record (55.65 million kilometers or 34.58 million miles).
Hubble Site contrasts the very distant opposition on February 12, 1995 (101.08 million kilometers) with the super-close opposition of August 28, 2003 (55.76 million kilometers). Image via Hubblesite
Distant Mars oppositions recur in cycles, too. Surprised? Of course, you aren’t. Cycles abound in outer space.
A particularly small or distant opposition of Mars will happen on February 19, 2027 (101.42 million kilometers or 63.02 million miles). Distant oppositions recur in periods of 15 to 17 years, so the years 2042 and 2044 will feature small oppositions, as well.
Neither Mars opposition will be as distant as the 2027 one, however.
Similarly distant oppositions recur in periods of 79 and 284 years. But we don’t find a more distant opposition than the one occurring in the year 2027 until 442 years later (284 years + 79 years + 79 years = 442 years), on February 27, 2469. At that time, the red planet will be a whopping 101.46 million kilometers (63.04 million miles) from Earth.
Telescopic image of Mars. During a close opposition, like the one in 2016, observers will make out more features on the planets surface. We won’t see Mars this size again until 2018, when Mars will put on an even better show. Illustration via nasa.tumblr.com.
Bottom line: This year, in 2016, enjoy the favorable opposition of May 22, as the red planet Mars shines in close vicinity of the planet Saturn and the red star Antares.
SkS Highlights... El Niño to La Niña... Toon of the Week... Quote of the Week... He Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...
SkS Highlights
Can the Republican Party solve its science denial problem? by Dana Nuccitelli garnered the highest number of comments among the articles posted on SkS during the past week. The article was originally posted on the Climate Consensus - the 97% Guardian blog maintained by Nuccitelli and John Abraham where it generated a lengthy and quite contentious comment thread. Click here to access the Guardian article and comment thread.
El Niño to La Niñposted on SkS during the past week. a
Withering drought and sizzling temperatures from El Nino have caused food and water shortages and ravaged farming across Asia, and experts warn of a double-whammy of possible flooding from its sibling, La Nina.
The current El Nino which began last year has been one of the strongest ever, leaving the Mekong River at its lowest level in decades, causing food-related unrest in the Philippines, and smothering vast regions in a months-long heat wave often topping 40 degrees Celsius (104 Fahrenheit).
Economic losses in Southeast Asia could top $10 billion, IHS Global Insight told AFP.
The regional fever is expected to break by mid-year but fears are growing that an equally forceful La Nina will follow.
That could bring heavy rain to an already flood-prone region, exacerbating agricultural damage and leaving crops vulnerable to disease and pests.
"Loss of oxygen in the oceans is one of the serious side effects of a warming atmosphere, and a major threat to marine life," said Matthew Long*, who is the lead author of the study. "Since oxygen concentrations in the ocean naturally vary depending on variations in winds and temperature at the surface, it's been challenging to attribute any de-oxygenation to climate change. This new study tells us when we can expect the effect from climate change to overwhelm the natural variability."
“The coal industry is being destroyed,” he* says. “And it’s scary to me because electricity is a staple of life — like potatoes were to the Irish. And Obama has largely destroyed reliable, low-cost, affordable electricity in America.”
*Robert E. Murray, chairman of the Murray Energy Corporation
The Carbon Pricing Leadership Coalition brings together leaders from across government, the private sector and civil society to share experience working with carbon pricing and to expand the evidence base for the most effective carbon pricing systems and policies.
The Coalition is a voluntary partnership of national and sub-national governments, businesses, and civil society organizations that agree to advance the carbon pricing agenda by working with each other towards the long-term objective of a carbon price applied throughout the global economy by:
strengthening carbon pricing policies to redirect investment commensurate with the scale of the climate challenge;
bringing forward and strengthening the implementation of existing carbon pricing policies to better manage investment risks and opportunities; and
enhancing cooperation to share information, expertise and lessons learned on developing and implementing carbon pricing through various "readiness" platforms
The Coalition will collect the evidence base, benefiting from experience around the world in designing and using carbon pricing, and use this input to help inform successful carbon pricing policy development and use of carbon pricing in businesses. It will also deepen understanding of the business and economic case for carbon pricing. In that role, it is developing pathways for use by companies, investors and governments that will illustrate plausible outlooks under a variety of carbon pricing policies and timelines. Finally, the coalition will work to bring together government and business in leadership dialogues that identify and address the most pressing issues, and in doing so, accelerate the use of carbon pricing around the world.
Coming Soon on SkS
Peabody coal's contrarian scientist witnesses lose their court case (John Abraham)
Handy resources when facing a firehose of falsehoods (Baerbel)
Scientists are figuring out the keys to convincing people about global warming (Dana)
Consensus on Consensus (AndyS)
Deep sea microbes may be key to oceans’ climate change feedback (Howard Lee)
SkS Highlights... El Niño to La Niña... Toon of the Week... Quote of the Week... He Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...
SkS Highlights
Can the Republican Party solve its science denial problem? by Dana Nuccitelli garnered the highest number of comments among the articles posted on SkS during the past week. The article was originally posted on the Climate Consensus - the 97% Guardian blog maintained by Nuccitelli and John Abraham where it generated a lengthy and quite contentious comment thread. Click here to access the Guardian article and comment thread.
El Niño to La Niñposted on SkS during the past week. a
Withering drought and sizzling temperatures from El Nino have caused food and water shortages and ravaged farming across Asia, and experts warn of a double-whammy of possible flooding from its sibling, La Nina.
The current El Nino which began last year has been one of the strongest ever, leaving the Mekong River at its lowest level in decades, causing food-related unrest in the Philippines, and smothering vast regions in a months-long heat wave often topping 40 degrees Celsius (104 Fahrenheit).
Economic losses in Southeast Asia could top $10 billion, IHS Global Insight told AFP.
The regional fever is expected to break by mid-year but fears are growing that an equally forceful La Nina will follow.
That could bring heavy rain to an already flood-prone region, exacerbating agricultural damage and leaving crops vulnerable to disease and pests.
"Loss of oxygen in the oceans is one of the serious side effects of a warming atmosphere, and a major threat to marine life," said Matthew Long*, who is the lead author of the study. "Since oxygen concentrations in the ocean naturally vary depending on variations in winds and temperature at the surface, it's been challenging to attribute any de-oxygenation to climate change. This new study tells us when we can expect the effect from climate change to overwhelm the natural variability."
“The coal industry is being destroyed,” he* says. “And it’s scary to me because electricity is a staple of life — like potatoes were to the Irish. And Obama has largely destroyed reliable, low-cost, affordable electricity in America.”
*Robert E. Murray, chairman of the Murray Energy Corporation
The Carbon Pricing Leadership Coalition brings together leaders from across government, the private sector and civil society to share experience working with carbon pricing and to expand the evidence base for the most effective carbon pricing systems and policies.
The Coalition is a voluntary partnership of national and sub-national governments, businesses, and civil society organizations that agree to advance the carbon pricing agenda by working with each other towards the long-term objective of a carbon price applied throughout the global economy by:
strengthening carbon pricing policies to redirect investment commensurate with the scale of the climate challenge;
bringing forward and strengthening the implementation of existing carbon pricing policies to better manage investment risks and opportunities; and
enhancing cooperation to share information, expertise and lessons learned on developing and implementing carbon pricing through various "readiness" platforms
The Coalition will collect the evidence base, benefiting from experience around the world in designing and using carbon pricing, and use this input to help inform successful carbon pricing policy development and use of carbon pricing in businesses. It will also deepen understanding of the business and economic case for carbon pricing. In that role, it is developing pathways for use by companies, investors and governments that will illustrate plausible outlooks under a variety of carbon pricing policies and timelines. Finally, the coalition will work to bring together government and business in leadership dialogues that identify and address the most pressing issues, and in doing so, accelerate the use of carbon pricing around the world.
Coming Soon on SkS
Peabody coal's contrarian scientist witnesses lose their court case (John Abraham)
Handy resources when facing a firehose of falsehoods (Baerbel)
Scientists are figuring out the keys to convincing people about global warming (Dana)
Consensus on Consensus (AndyS)
Deep sea microbes may be key to oceans’ climate change feedback (Howard Lee)
View larger. | Image via NASA/JPL-Caltech/Space Science Institute.
Are Saturn’s rings criss-crossed in this February, 2016, Cassini spacecraft image? No. It’s not a new discovery, just an illusion caused by the fact that Saturn’s rings aren’t solid objects. NASA said:
At first glance, Saturn’s rings appear to be intersecting themselves in an impossible way. In actuality, this view … shows the rings in front of the planet, upon which the shadow of the rings is cast.
Saturn’s rings are composed of millions of tiny moonlets. They aren’t solid; we can see through them. And that’s why we can see the shadow of the rings behind the rings themselves, creating this apparent criss-cross. Speaking of this image, NASA went on to say:
Saturn’s rings have complex and detailed structures, many of which can be seen here. In some cases, the reasons for the gaps and ringlets are known; for example, Pan (17 miles or 28 kilometers across) — seen here near image center — keeps open the Encke gap. But in other cases, the origins and natures of gaps and ringlets are still poorly understood.
This view looks toward the sunlit side of the rings from about 14 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 11, 2016.
The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 85 degrees. Image scale is 6 miles (10 kilometers) per pixel.
View larger. | Image via NASA/JPL-Caltech/Space Science Institute.
Are Saturn’s rings criss-crossed in this February, 2016, Cassini spacecraft image? No. It’s not a new discovery, just an illusion caused by the fact that Saturn’s rings aren’t solid objects. NASA said:
At first glance, Saturn’s rings appear to be intersecting themselves in an impossible way. In actuality, this view … shows the rings in front of the planet, upon which the shadow of the rings is cast.
Saturn’s rings are composed of millions of tiny moonlets. They aren’t solid; we can see through them. And that’s why we can see the shadow of the rings behind the rings themselves, creating this apparent criss-cross. Speaking of this image, NASA went on to say:
Saturn’s rings have complex and detailed structures, many of which can be seen here. In some cases, the reasons for the gaps and ringlets are known; for example, Pan (17 miles or 28 kilometers across) — seen here near image center — keeps open the Encke gap. But in other cases, the origins and natures of gaps and ringlets are still poorly understood.
This view looks toward the sunlit side of the rings from about 14 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 11, 2016.
The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 85 degrees. Image scale is 6 miles (10 kilometers) per pixel.
“Science is the only self-correcting human institution, but it also is a process that progresses only by showing itself to be wrong.” -Allan Sandage
As April leaves us and May commences here at Starts With A Bang, I’m so pleased to inform you that amazing things are happening! Thanks to the support of everyone on Patreon, we’re over 95% of the way towards our next goal: the creation of the most accurate, beautiful, scientific timeline of the Universe’s history poster ever made! We’ve also covered the following topics this past week for you to ring in on:
Our Podcasts are coming along, too, as our Patreon supporters have chosen May’s topic (on dark energy), and someone, unsolicited (Philipp Dettmer, thank you!) has made me my first piece of fanart of me!
Image credit: Japan Meteorological Association (JMA), of the monthly average temperatures in February, going back as far as temperature records do. Via the Sydney Morning Herald at http://ift.tt/1LqCRlA.
From Ragtag Media on climate tampering: “I back up my skepticism with not just my unabridged worldly opinion but with a variety of others.
Here, that this one: Massive Tampering With Temperatures In South America: http://ift.tt/1EmJj4J“
What you call “tampering” is what scientists call “adjustments”. Now you can say, “why don’t you just use the raw temperatures and be done with it,” but the reason is important: you are using these temperature measurements as proxies for the entire globe, and yet you are measuring them at limited, specific (often city-centric) locations located at ground-level. What do you do about the fact that paved roads increase (artificially) the temperatures you measure? What do you do about the fact that different stations give data with different quality levels? What do you do about fires when they occur nearby, or when factories are turned on vs. off?
If you say, “just give me the raw data,” you know you’re not accurately representing the global temperature. If you make the appropriate adjustments to the best of your scientific knowledge, how is that equivalent to “tampering” in any negative sense of the word? I’m going to say what I’ve said before to you: it sounds like you’re basing which argument you side with on the conclusions that are reached. If the temperature is warming, you refute that fact. If you accept warming temperatures, you refute that it’s human-caused. If you accept that it’s human-caused, you refute that it’s a bad thing. And if you accept that it’s a bad thing, you refute that there’s anything we can do. Remind me of where you are in that progression again?
Image credit: Breakthrough Starshot, of the laser sail concept for a “starchip” spaceship.
From PJ on slowing down a starshot: “Makes an interesting enigma – get to the target planet first, set up a power grid and laser site to slow the probes down on their arrival so that we can explore the local environment to decide where to set up our base.
The chicken and the egg again?”
Quite honestly, I think the conclusion we need to accept is not that we have to send a slowpoke-system to another star in order to properly explore it, but rather that sending a “starchip” starship to another system is just a cool technological feat on its own, and that the R&D that goes into developing the technology is fascinating and useful in its applications in a myriad of other ways. Think about the progress that will be made in:
light, strong, reflective materials,
laser technology,
laser collimation technology,
laser sail steering and stabilization,
miniaturization microchip technology,
and effectively 2D transmission and communication technology,
among others. We don’t need to get 100% of the way there to have something worth bragging about, or something that benefits society in a greater way than any individual efforts could do on their own.
A logarithmic chart of distances, showing the Voyager spacecraft, our Solar System and our nearest star, for comparison. Image credit: NASA / JPL-Caltech.
From Michael Kelsey on predicting the laser sail’s demise from collisions: “With an average interstellar density of a few atoms per cubic centimeter (1e-4 in hot, ionized regions to 1e+6 in molecular clouds), a solar sail with an area of 1 km2 at 0.2 c will see a flux of something like 6e+16 impacts per second, or a heat load of 192 kW.”
This is the main part of your estimation I’m unsure of. Your density numbers look good, your area looks good and your speed looks good. But impacts? I’m thinking of the famous Rutherford experiment, and the fact that if most of what we’re likely to encounter is ionized rather than neutral (and bound), most of these particles will simply pass through this thin sail with no collision at all. In other words, the number of impacts and the heat load may be many orders of magnitude lower than your estimate.
The concept art of a solar sail (Japan’s IKAROS project) at a distant planet or star system. Image credit: Andrzej Mirecki of Wikimedia Commons, under a c.c.a.-s.a.-3.0 license.
But I do wholeheartedly agree that each impact that does occur will not only be catastrophic as far as ionization (or even nuclear dissociation) goes, but a good fraction will conceivably result in e+/e- pair production as well. This is not necessarily going to be a happy, intact sail upon arrival is what I’m saying.
Jupiter and its rings, bands and other heat-sensitive features in the infrared. Image credit: user Trocche100 at the Italian Wikipedia.
From eric on the rings of the gas giants: “I am also amazed that the structures remaining after the ~5 billion years our solar system has been around, are structures that would be stable for >=5 billion years. What an amazing, miraculous coincidence. Oh celestial mechanics, you trickster you!”
There are a couple of important points to highlight: a fraction of the ringed systems present us with rings that appear to be truly stable, as they may exist for the remainder of the Solar System, while others require creation and shepherding by moons. The outer rings of Saturn — created by Enceladus and Phoebe — are of the latter type, as are the rings of Jupiter and Neptune. The main rings of Saturn, as well as the majority of Uranus’ rings, may be of the more stable type.
Image credit: NASA/JPL/Space Science Institute, of Saturn’s E-ring, with Enceladus as the brightest spot.
But, as Denier and Michael Kelsey rightly point out, that doesn’t mean it’s easy to determine whether Saturn’s rings are ~100 million years old, ~4.5 billion years old, any number in between, or whether these are even the first incarnation of rings around it. As we all need to remember, there are many things that erase the early history of our Solar System, and now that we’re finally here, all we can see are the survivors.
Image credit: Wikipedia / Wikimedia Commons user Qashqaiilove.
From Denier on the strong force: “Are the Color Force and the Strong Nuclear Force the same thing?”
Although there is a good discussion that follows Denier’s comment led by Michael Kelsey, I’d like to chime in a little bit as well here. The strong nuclear force is one of the fundamental forces, and it comes in two manifestations:
the binding force that holds mesons and baryons together through quark-gluon (or antiquark-gluon) interactions, and
the binding force that holds atomic nuclei together, through (virtual) meson interactions.
Color force is an analogy to help us visualize this. If we allow quarks to be colored red, green or blue, and antiquarks to be colored cyan, magenta and yellow, then we can arrive at a colorless combination by having either a quark-antiquark combo or a 3-quark/3-antiquark combo. (Or superpositions of those: 1-quark/4-antiquarks, 2-quarks/2-antiquarks, 6-quarks, etc.)
Image credit: E. Siegel, from his new book, Beyond The Galaxy.
You might imagine, from this, that there are six gluons, but in fact there are eight. (Because 3^2-1=8, which is a property of SU(3).) And while asymptotic freedom tells us that the strong force goes to zero at very short distances, it also goes to zero as soon as you begin moving away from a color-neutral entity. (I believe, IIRC, it scales as 1/r^6, which is why the strong nuclear force dies off so fast and we can’t have very large nuclei for long.) I wrote a longer piece on this a while ago called The Strong Force For Beginners that goes over some of this in more detail, that you may enjoy.
The four beams emerging from the new laser system on Unit Telescope 4 of the VLT. Image credit: ESO/F. Kamphues.
From Omega Centauri on guide stars, delays and adaptive optics: “Now how does the detector/computer combo, know which portions are delayed/advanced, from only looking at one image (unless its actually measuring the arrival time from a concentrated pule -which I really really doubt is possible)? Or is it just trying a bunch of perturbations and seeing what happens, or is their something really clever going on?”
The wonderful thing about light is that it always moves at the speed of light, so if you delay the light’s arrival time by a certain, known amount, you know exactly how much “behind” your moving mirror is the actual light. Take a close look at the snapshot below.
Image credit: Gemini Observatory – Adaptive Optics – Laser Guide Star, annotation by E. Siegel.
There’s a copy of the light being sent along the red path, while a fraction of the incoming light arrives at the purple path (at the bottom), telling us what the atmospheric distortion was at that moment. By time that red light arrives at the orange “distortion-removal” mirror, the purple signal has told the mirror what shape to be in to do the adaptation. As the next wavefront comes in, the mirror has adapted again. This adaptation is continuous and interpolated, and therefore imperfect, which is part of the inherent limitation of the technique. But the results are still amazing, and it kind of is like undistorting one snapshot at a time!
The effects of the Earth’s Atmosphere on the Telescopic Image of alpha Piscium from Edinburgh and from Alta Vista 10,700 ft., compared. From a 1863 engraving by Charles Piazzi Smyth, in the public domain.
From PJ on AO and giant telescopes for amateurs: “The best thing about the technology is that it will soon be possible for the backyard operator to run a similar setup in small scale. A 36 to 40 inch reflector in a dome is not out of the question in the near future. The cost of sodium lasers will eventually drop with demand. Quite a challenge, methinks.”
I hate to say it, but “amateurs” have had ~24″ telescopes at their disposal since the late 1800s, which is how Isaac Roberts took the very first picture of a galaxy beyond our own.
Image credit: Isaac Roberts, from A Selection of Photographs of Stars, Star-clusters and Nebulae, Volume II, The Universal Press, London, 1899.
The powerful sodium laser isn’t the most expensive part, either; the adaptive mirror is. If you can get your hands on that, the software is free, and the rest is up to you to put the whole configuration together. Jim Misti and Adam Block are two of the more famous astrophotographers I admire, and their “amateur” status is a testament to how much one can do with off-the-shelf technology!
Image credit: European Gravitational Observatory, Lionel BRET/EUROLIOS.
From See Noevo on the speed of gravity equalling the speed of light: “Must have been a slow news day in science.”
Some days, you report the news by talking about a new discovery (or new hype); other days, you make the news by talking about something that is known by the experts, but by bringing it to a level that non-experts can understand. Science is always happening, but science communication only happens as science communicators choose it. Hopefully you enjoyed learning about this!
Image credit: David Champion, Max Planck Institute for Radio Astronomy.
From Veri Tay on some blatantly untrue stuff: “Lol, gravity is instant, really all of modern so-called science is a bunch of lies. Primary light travels instantly – we see the universe in real-time.”
It must have been fun to just make all these authoritative sounding statements without any facts or evidence to back them up. If everything is instantaneous, why are there time delays in the arrival of everything from gravitational wave pulses to the arrival of New Horizons’ data from beyond Pluto to signals sent to-and-from the Moon.
Remember? Or at least, remember watching the footage of it? If you don’t, here’s what I want you to do. Take your cellphone and call your friend that you’re actually, physically with. Go have them sit in a car while you stand outside the car. Have a conversation with them on your cellphone and watch their lips move, and pay attention to when you hear their voice in your phone versus when you see their lips move. That’s your evidence, right there, that the Universe is not instantaneous.
And finally, from Naked Bunny with a whip on inhomogeneities: “I can safely say the water in my glass is of a uniform average density, even though most of the mass is concentrated into tiny nucleons surrounded by relatively vast stretches of space, and there are doubtless small temperature variations.”
One of my favorite analogies to use for the level of inhomogeneity in the Universe — and you can find this in my book — is the surface of the ocean. If you imagine the ocean, some 3 miles (5 km) deep, and surface level waves maybe 1-10 cm in magnitude, the differences between the peaks and troughs relative to the entire depth of the ocean is similar to the initial differences between overdense and underdense regions in the Universe.
Fluctuations in the ocean relative to fluctuations in the density of the Universe. Images credit: E. Siegel and the COBE satellite/NASA.
Over time, however, small scales have more time to gravitationally collapse, meaning we get greater density fluctuations on smaller scales today and smaller fluctuations, or smaller departures from the initial fluctuations, on the larger scales. That’s what we’ve got, and that’s consistent with what we expect!
Thanks for a great week, everyone, and I’ll see you back here tomorrow for more wonders of the Universe, more stories, more science and more Starts With A Bang!
from ScienceBlogs http://ift.tt/1NMf7ZX
“Science is the only self-correcting human institution, but it also is a process that progresses only by showing itself to be wrong.” -Allan Sandage
As April leaves us and May commences here at Starts With A Bang, I’m so pleased to inform you that amazing things are happening! Thanks to the support of everyone on Patreon, we’re over 95% of the way towards our next goal: the creation of the most accurate, beautiful, scientific timeline of the Universe’s history poster ever made! We’ve also covered the following topics this past week for you to ring in on:
Our Podcasts are coming along, too, as our Patreon supporters have chosen May’s topic (on dark energy), and someone, unsolicited (Philipp Dettmer, thank you!) has made me my first piece of fanart of me!
Image credit: Japan Meteorological Association (JMA), of the monthly average temperatures in February, going back as far as temperature records do. Via the Sydney Morning Herald at http://ift.tt/1LqCRlA.
From Ragtag Media on climate tampering: “I back up my skepticism with not just my unabridged worldly opinion but with a variety of others.
Here, that this one: Massive Tampering With Temperatures In South America: http://ift.tt/1EmJj4J“
What you call “tampering” is what scientists call “adjustments”. Now you can say, “why don’t you just use the raw temperatures and be done with it,” but the reason is important: you are using these temperature measurements as proxies for the entire globe, and yet you are measuring them at limited, specific (often city-centric) locations located at ground-level. What do you do about the fact that paved roads increase (artificially) the temperatures you measure? What do you do about the fact that different stations give data with different quality levels? What do you do about fires when they occur nearby, or when factories are turned on vs. off?
If you say, “just give me the raw data,” you know you’re not accurately representing the global temperature. If you make the appropriate adjustments to the best of your scientific knowledge, how is that equivalent to “tampering” in any negative sense of the word? I’m going to say what I’ve said before to you: it sounds like you’re basing which argument you side with on the conclusions that are reached. If the temperature is warming, you refute that fact. If you accept warming temperatures, you refute that it’s human-caused. If you accept that it’s human-caused, you refute that it’s a bad thing. And if you accept that it’s a bad thing, you refute that there’s anything we can do. Remind me of where you are in that progression again?
Image credit: Breakthrough Starshot, of the laser sail concept for a “starchip” spaceship.
From PJ on slowing down a starshot: “Makes an interesting enigma – get to the target planet first, set up a power grid and laser site to slow the probes down on their arrival so that we can explore the local environment to decide where to set up our base.
The chicken and the egg again?”
Quite honestly, I think the conclusion we need to accept is not that we have to send a slowpoke-system to another star in order to properly explore it, but rather that sending a “starchip” starship to another system is just a cool technological feat on its own, and that the R&D that goes into developing the technology is fascinating and useful in its applications in a myriad of other ways. Think about the progress that will be made in:
light, strong, reflective materials,
laser technology,
laser collimation technology,
laser sail steering and stabilization,
miniaturization microchip technology,
and effectively 2D transmission and communication technology,
among others. We don’t need to get 100% of the way there to have something worth bragging about, or something that benefits society in a greater way than any individual efforts could do on their own.
A logarithmic chart of distances, showing the Voyager spacecraft, our Solar System and our nearest star, for comparison. Image credit: NASA / JPL-Caltech.
From Michael Kelsey on predicting the laser sail’s demise from collisions: “With an average interstellar density of a few atoms per cubic centimeter (1e-4 in hot, ionized regions to 1e+6 in molecular clouds), a solar sail with an area of 1 km2 at 0.2 c will see a flux of something like 6e+16 impacts per second, or a heat load of 192 kW.”
This is the main part of your estimation I’m unsure of. Your density numbers look good, your area looks good and your speed looks good. But impacts? I’m thinking of the famous Rutherford experiment, and the fact that if most of what we’re likely to encounter is ionized rather than neutral (and bound), most of these particles will simply pass through this thin sail with no collision at all. In other words, the number of impacts and the heat load may be many orders of magnitude lower than your estimate.
The concept art of a solar sail (Japan’s IKAROS project) at a distant planet or star system. Image credit: Andrzej Mirecki of Wikimedia Commons, under a c.c.a.-s.a.-3.0 license.
But I do wholeheartedly agree that each impact that does occur will not only be catastrophic as far as ionization (or even nuclear dissociation) goes, but a good fraction will conceivably result in e+/e- pair production as well. This is not necessarily going to be a happy, intact sail upon arrival is what I’m saying.
Jupiter and its rings, bands and other heat-sensitive features in the infrared. Image credit: user Trocche100 at the Italian Wikipedia.
From eric on the rings of the gas giants: “I am also amazed that the structures remaining after the ~5 billion years our solar system has been around, are structures that would be stable for >=5 billion years. What an amazing, miraculous coincidence. Oh celestial mechanics, you trickster you!”
There are a couple of important points to highlight: a fraction of the ringed systems present us with rings that appear to be truly stable, as they may exist for the remainder of the Solar System, while others require creation and shepherding by moons. The outer rings of Saturn — created by Enceladus and Phoebe — are of the latter type, as are the rings of Jupiter and Neptune. The main rings of Saturn, as well as the majority of Uranus’ rings, may be of the more stable type.
Image credit: NASA/JPL/Space Science Institute, of Saturn’s E-ring, with Enceladus as the brightest spot.
But, as Denier and Michael Kelsey rightly point out, that doesn’t mean it’s easy to determine whether Saturn’s rings are ~100 million years old, ~4.5 billion years old, any number in between, or whether these are even the first incarnation of rings around it. As we all need to remember, there are many things that erase the early history of our Solar System, and now that we’re finally here, all we can see are the survivors.
Image credit: Wikipedia / Wikimedia Commons user Qashqaiilove.
From Denier on the strong force: “Are the Color Force and the Strong Nuclear Force the same thing?”
Although there is a good discussion that follows Denier’s comment led by Michael Kelsey, I’d like to chime in a little bit as well here. The strong nuclear force is one of the fundamental forces, and it comes in two manifestations:
the binding force that holds mesons and baryons together through quark-gluon (or antiquark-gluon) interactions, and
the binding force that holds atomic nuclei together, through (virtual) meson interactions.
Color force is an analogy to help us visualize this. If we allow quarks to be colored red, green or blue, and antiquarks to be colored cyan, magenta and yellow, then we can arrive at a colorless combination by having either a quark-antiquark combo or a 3-quark/3-antiquark combo. (Or superpositions of those: 1-quark/4-antiquarks, 2-quarks/2-antiquarks, 6-quarks, etc.)
Image credit: E. Siegel, from his new book, Beyond The Galaxy.
You might imagine, from this, that there are six gluons, but in fact there are eight. (Because 3^2-1=8, which is a property of SU(3).) And while asymptotic freedom tells us that the strong force goes to zero at very short distances, it also goes to zero as soon as you begin moving away from a color-neutral entity. (I believe, IIRC, it scales as 1/r^6, which is why the strong nuclear force dies off so fast and we can’t have very large nuclei for long.) I wrote a longer piece on this a while ago called The Strong Force For Beginners that goes over some of this in more detail, that you may enjoy.
The four beams emerging from the new laser system on Unit Telescope 4 of the VLT. Image credit: ESO/F. Kamphues.
From Omega Centauri on guide stars, delays and adaptive optics: “Now how does the detector/computer combo, know which portions are delayed/advanced, from only looking at one image (unless its actually measuring the arrival time from a concentrated pule -which I really really doubt is possible)? Or is it just trying a bunch of perturbations and seeing what happens, or is their something really clever going on?”
The wonderful thing about light is that it always moves at the speed of light, so if you delay the light’s arrival time by a certain, known amount, you know exactly how much “behind” your moving mirror is the actual light. Take a close look at the snapshot below.
Image credit: Gemini Observatory – Adaptive Optics – Laser Guide Star, annotation by E. Siegel.
There’s a copy of the light being sent along the red path, while a fraction of the incoming light arrives at the purple path (at the bottom), telling us what the atmospheric distortion was at that moment. By time that red light arrives at the orange “distortion-removal” mirror, the purple signal has told the mirror what shape to be in to do the adaptation. As the next wavefront comes in, the mirror has adapted again. This adaptation is continuous and interpolated, and therefore imperfect, which is part of the inherent limitation of the technique. But the results are still amazing, and it kind of is like undistorting one snapshot at a time!
The effects of the Earth’s Atmosphere on the Telescopic Image of alpha Piscium from Edinburgh and from Alta Vista 10,700 ft., compared. From a 1863 engraving by Charles Piazzi Smyth, in the public domain.
From PJ on AO and giant telescopes for amateurs: “The best thing about the technology is that it will soon be possible for the backyard operator to run a similar setup in small scale. A 36 to 40 inch reflector in a dome is not out of the question in the near future. The cost of sodium lasers will eventually drop with demand. Quite a challenge, methinks.”
I hate to say it, but “amateurs” have had ~24″ telescopes at their disposal since the late 1800s, which is how Isaac Roberts took the very first picture of a galaxy beyond our own.
Image credit: Isaac Roberts, from A Selection of Photographs of Stars, Star-clusters and Nebulae, Volume II, The Universal Press, London, 1899.
The powerful sodium laser isn’t the most expensive part, either; the adaptive mirror is. If you can get your hands on that, the software is free, and the rest is up to you to put the whole configuration together. Jim Misti and Adam Block are two of the more famous astrophotographers I admire, and their “amateur” status is a testament to how much one can do with off-the-shelf technology!
Image credit: European Gravitational Observatory, Lionel BRET/EUROLIOS.
From See Noevo on the speed of gravity equalling the speed of light: “Must have been a slow news day in science.”
Some days, you report the news by talking about a new discovery (or new hype); other days, you make the news by talking about something that is known by the experts, but by bringing it to a level that non-experts can understand. Science is always happening, but science communication only happens as science communicators choose it. Hopefully you enjoyed learning about this!
Image credit: David Champion, Max Planck Institute for Radio Astronomy.
From Veri Tay on some blatantly untrue stuff: “Lol, gravity is instant, really all of modern so-called science is a bunch of lies. Primary light travels instantly – we see the universe in real-time.”
It must have been fun to just make all these authoritative sounding statements without any facts or evidence to back them up. If everything is instantaneous, why are there time delays in the arrival of everything from gravitational wave pulses to the arrival of New Horizons’ data from beyond Pluto to signals sent to-and-from the Moon.
Remember? Or at least, remember watching the footage of it? If you don’t, here’s what I want you to do. Take your cellphone and call your friend that you’re actually, physically with. Go have them sit in a car while you stand outside the car. Have a conversation with them on your cellphone and watch their lips move, and pay attention to when you hear their voice in your phone versus when you see their lips move. That’s your evidence, right there, that the Universe is not instantaneous.
And finally, from Naked Bunny with a whip on inhomogeneities: “I can safely say the water in my glass is of a uniform average density, even though most of the mass is concentrated into tiny nucleons surrounded by relatively vast stretches of space, and there are doubtless small temperature variations.”
One of my favorite analogies to use for the level of inhomogeneity in the Universe — and you can find this in my book — is the surface of the ocean. If you imagine the ocean, some 3 miles (5 km) deep, and surface level waves maybe 1-10 cm in magnitude, the differences between the peaks and troughs relative to the entire depth of the ocean is similar to the initial differences between overdense and underdense regions in the Universe.
Fluctuations in the ocean relative to fluctuations in the density of the Universe. Images credit: E. Siegel and the COBE satellite/NASA.
Over time, however, small scales have more time to gravitationally collapse, meaning we get greater density fluctuations on smaller scales today and smaller fluctuations, or smaller departures from the initial fluctuations, on the larger scales. That’s what we’ve got, and that’s consistent with what we expect!
Thanks for a great week, everyone, and I’ll see you back here tomorrow for more wonders of the Universe, more stories, more science and more Starts With A Bang!
