Heading into 2016, EPA is building on a monumental year for climate action—and we’re not slowing down in the year ahead. Last August, President Obama announced the final Clean Power Plan, EPA’s historic rule to cut carbon pollution from power plants, our nation’s largest driver of climate change. Then in Paris last month, nearly 200 countries came together for the first time ever to announce a universal agreement to act on climate.
So we’re hitting the ground running. Under the Paris Agreement, countries pledge to limit global warming to two degrees Celsius at most, and pursue efforts to keep it below 1.5 degrees Celsius. Science tells us these levels will help prevent some of the most devastating impacts of climate change, including more frequent and extreme droughts, storms, fires, and floods, as well as catastrophic sea level rise. This agreement applies to all countries, sets meaningful accountability and reporting requirements, and brings countries back to the table every five years to grow their commitments as markets change and technologies improve. It also provides financing mechanisms so developing economies can move forward using clean energy.
This year, we’ll build on these successes to ensure lasting climate action that protects Americans’ health, economic opportunity, and national security. EPA staff will provide their technical leadership to ensure consistent, transparent greenhouse gas reporting and inventory requirements under the Paris Agreement. Our domestic expertise in air quality monitoring and greenhouse gas inventories will help countries make sure they’re meeting their greenhouse gas reduction goals. Similarly, we’ll use our expertise to identify and evaluate substitutes in the U.S. to reduce hydrofluorocarbons (HFCs), another potent climate pollutant. This work domestically will help us lead global efforts to finalize a requirement in 2016 for countries to reduce production and use of HFCs under the Montreal Protocol.
We will finalize a proposal to improve fuel economy and cut carbon pollution from heavy-duty vehicles, which could avoid a billion metric tons of carbon pollution and save 75 billion gallons of fuel by 2027. We’ll also finalize rules to limit methane leaks from oil and gas operations—which could avoid up to 400,000 metric tons of a climate pollutant 25 times more potent than carbon dioxide by 2025. Meanwhile, we’re doubling the distance our cars go on a gallon of gas by 2025.
In 2016, EPA will defend and implement the Clean Power Plan by working closely with states and stakeholders to help them create strong plans to reduce their carbon pollution. We wrote this plan with unprecedented stakeholder input, including hundreds of meetings across the country and 4.3 million public comments. The result is a rule that’s ambitious but achievable, and falls squarely within the four corners of the Clean Air Act, a statute we have been successfully implementing for 45 years. We’re confident the Clean Power Plan will stand the test of time—the Supreme Court has ruled three times that EPA has not only the authority but the obligation to limit harmful carbon pollution under the Clean Air Act.
Just as importantly, the Paris Agreement and the Clean Power Plan are helping mobilize private capital all over the world toward low-carbon investments. The U.S. has sent a clear signal that a low-carbon future is inevitable, and that the market will reward those who develop low-carbon technologies and make their assets resistant to climate impacts. That’s why 154 of the largest U.S. companies, representing 11 million jobs and more than seven trillion dollars in market capitalization, have signed the White House American Business Act on Climate Pledge. Companies like Walmart, AT&T, Facebook, and Coca-Cola recognize that climate impacts threaten their operations, while investing in a low-carbon future is an unprecedented business opportunity.
Americans know climate action is critical—they’re seeing its impacts with their own eyes. Hurricanes, droughts, wildfires, and storms are growing more frequent and extreme. Streets in cities like Miami now flood on sunny days due to sea level rise. Climate change is a moral issue, a health issue, and a jobs issue—and that’s why the strong majority of Americans want the federal government to do something about it, and support the strong outcome in Paris.
We’ve got a lot more work to do, and we’re not slowing down. Over the past year, we’ve seen remarkable climate achievements that once seemed impossible—and that’s thanks to President Obama’s leadership. His climate legacy is already impressive, but we will build on it in 2016 by continuing to protect health and opportunity for all Americans. At EPA, we’ve got our sleeves rolled up.
from The EPA Blog http://ift.tt/1OGHTVP
By Gina McCarthy
Heading into 2016, EPA is building on a monumental year for climate action—and we’re not slowing down in the year ahead. Last August, President Obama announced the final Clean Power Plan, EPA’s historic rule to cut carbon pollution from power plants, our nation’s largest driver of climate change. Then in Paris last month, nearly 200 countries came together for the first time ever to announce a universal agreement to act on climate.
So we’re hitting the ground running. Under the Paris Agreement, countries pledge to limit global warming to two degrees Celsius at most, and pursue efforts to keep it below 1.5 degrees Celsius. Science tells us these levels will help prevent some of the most devastating impacts of climate change, including more frequent and extreme droughts, storms, fires, and floods, as well as catastrophic sea level rise. This agreement applies to all countries, sets meaningful accountability and reporting requirements, and brings countries back to the table every five years to grow their commitments as markets change and technologies improve. It also provides financing mechanisms so developing economies can move forward using clean energy.
This year, we’ll build on these successes to ensure lasting climate action that protects Americans’ health, economic opportunity, and national security. EPA staff will provide their technical leadership to ensure consistent, transparent greenhouse gas reporting and inventory requirements under the Paris Agreement. Our domestic expertise in air quality monitoring and greenhouse gas inventories will help countries make sure they’re meeting their greenhouse gas reduction goals. Similarly, we’ll use our expertise to identify and evaluate substitutes in the U.S. to reduce hydrofluorocarbons (HFCs), another potent climate pollutant. This work domestically will help us lead global efforts to finalize a requirement in 2016 for countries to reduce production and use of HFCs under the Montreal Protocol.
We will finalize a proposal to improve fuel economy and cut carbon pollution from heavy-duty vehicles, which could avoid a billion metric tons of carbon pollution and save 75 billion gallons of fuel by 2027. We’ll also finalize rules to limit methane leaks from oil and gas operations—which could avoid up to 400,000 metric tons of a climate pollutant 25 times more potent than carbon dioxide by 2025. Meanwhile, we’re doubling the distance our cars go on a gallon of gas by 2025.
In 2016, EPA will defend and implement the Clean Power Plan by working closely with states and stakeholders to help them create strong plans to reduce their carbon pollution. We wrote this plan with unprecedented stakeholder input, including hundreds of meetings across the country and 4.3 million public comments. The result is a rule that’s ambitious but achievable, and falls squarely within the four corners of the Clean Air Act, a statute we have been successfully implementing for 45 years. We’re confident the Clean Power Plan will stand the test of time—the Supreme Court has ruled three times that EPA has not only the authority but the obligation to limit harmful carbon pollution under the Clean Air Act.
Just as importantly, the Paris Agreement and the Clean Power Plan are helping mobilize private capital all over the world toward low-carbon investments. The U.S. has sent a clear signal that a low-carbon future is inevitable, and that the market will reward those who develop low-carbon technologies and make their assets resistant to climate impacts. That’s why 154 of the largest U.S. companies, representing 11 million jobs and more than seven trillion dollars in market capitalization, have signed the White House American Business Act on Climate Pledge. Companies like Walmart, AT&T, Facebook, and Coca-Cola recognize that climate impacts threaten their operations, while investing in a low-carbon future is an unprecedented business opportunity.
Americans know climate action is critical—they’re seeing its impacts with their own eyes. Hurricanes, droughts, wildfires, and storms are growing more frequent and extreme. Streets in cities like Miami now flood on sunny days due to sea level rise. Climate change is a moral issue, a health issue, and a jobs issue—and that’s why the strong majority of Americans want the federal government to do something about it, and support the strong outcome in Paris.
We’ve got a lot more work to do, and we’re not slowing down. Over the past year, we’ve seen remarkable climate achievements that once seemed impossible—and that’s thanks to President Obama’s leadership. His climate legacy is already impressive, but we will build on it in 2016 by continuing to protect health and opportunity for all Americans. At EPA, we’ve got our sleeves rolled up.
The Institute for Policy Integrity at the New York University (NYU) School of Law recently published a report summarizing a survey of economists with climate expertise. The report was a follow-up and expansion of a similar survey conducted in 2009 by the same institute. The key finding: there’s a strong consensus among climate economics experts that we should put a price on carbon pollution to curb the expensive costs of climate change.
The survey participants included economists who have published papers related to climate change “in a highly ranked, peer-reviewed economics or environmental economics journal since 1994.” Overall, 365 participants completed the survey, which established the consensus of expert climate economists on a number of important questions.
Carbon pollution cuts are needed regardless of what other countries do
In the 2009 version of the survey, the respondents were asked under what conditions the United States should commit to reducing greenhouse gas emissions. 57% answered that the US should cut its emissions no matter what actions other countries take, while another 38% said that American emissions cuts would be warranted if many or all other countries commit to reducing theirs (as just happened in the Paris international negotiations).
In the 2015 survey, the number of expert economists saying that the US should cut its emissions no matter what rose to 77%. A further 18% said that if other countries agree to cut their emissions, the US should follow suit. In other words, there is a 95% consensus among expert climate economists that the US should follow through with its pledges to cut carbon pollution in the wake of the Paris international climate negotiations, and more than three out of four agreed that the US should take action to curb global warming no matter what.
2015 New York University survey results of economists with climate expertise when asked under what circumstances the USA should reduce its emissions
This expert consensus is in stark contrast to conservative political opposition to the Paris accord. For example, Republican presidential candidate Marco Rubio said of the agreement,
This kind of unilateral disarmament in our economy is reckless, and it is hurting the American Dream
Quite obviously an international agreement made by 195 nations around the world is the antithesis of unilateral action. However, 77% of expert economists agree that unilateral action would be appropriate in any case, directly contradicting Rubio’s comments. Additionally, 82% of the experts agreed that by implementing climate policies, the US could strategically induce other countries to cut their carbon pollution.
Climate change is already hurting the global economy
When asked at what date climate change will have a net negative impact on the global economy, the median survey response was 2025. In the recent past, climate change likely had a net positive impact on the global economy, due primarily to the effect of carbon fertilization on crops and other plant life. However, even contrarian economists agree, when accounting for the vulnerability of poorer countries to climate impacts, global warming has been hurting the global economy since about 1980.
The NYU survey asked when the economic benefits we experienced up to 1980 would be completely wiped out; 41% of respondents said that’s already happened. Another 25% answered that it would happen within a decade, and 26% said we’d see net negative economic impacts by 2050. If we continue with business-as-usual pollution and warming, on average the experts predicted a GDP loss of about 10% by the end of the century, and that there would be a 20% chance of a “catastrophic” loss of one-quarter of global GDP.
Figure 5 from ‘Expert Consensus on the Economics of Climate Change’ 2015 report by the NYU Institute for Policy Integrity.
Of course, ideally we would have stopped warming the planet in 1980 to preserve the economic benefits of global warming to that date. At this point it’s a question of just how much damage climate change will do to the global economy, and the economic experts are worried that the results could be catastrophic.
Climate change will hurt economic growth
78% of the survey participants said that it’s likely (36%) or extremely likely (42%) that climate change will have a long-term negative impact on the growth rate of the global economy. That’s an important point, because most current integrated economic-climate assessment models assume that economic growth will continue regardless of climate change impacts. There’s been a growing body of research indicating that as you might expect, that won’t be the case.
The results of this survey question show that most expert economists agree, climate change will hurt global economic growth. That also suggests that past model-based studies likely significantly underestimated the costs of climate change. Along the same lines, 51% of the experts answered that the US government’s estimate for the “social cost of carbon” ($37 per metric ton), which is largely based on estimates from these models, is too low. 18% of the experts said that value is about right, and just 8% said it’s too high.
Carbon pricing is an efficient way to cut pollution
The survey also asked the experts about the most economically efficient method of reducing carbon pollution. 81% said a market-based system (carbon tax or cap and trade system) would be most efficient, while 13% answered that coordinated performance standards and programs that prioritize cleaner fuels and energy efficiency would be most efficient.
The Institute for Policy Integrity at the New York University (NYU) School of Law recently published a report summarizing a survey of economists with climate expertise. The report was a follow-up and expansion of a similar survey conducted in 2009 by the same institute. The key finding: there’s a strong consensus among climate economics experts that we should put a price on carbon pollution to curb the expensive costs of climate change.
The survey participants included economists who have published papers related to climate change “in a highly ranked, peer-reviewed economics or environmental economics journal since 1994.” Overall, 365 participants completed the survey, which established the consensus of expert climate economists on a number of important questions.
Carbon pollution cuts are needed regardless of what other countries do
In the 2009 version of the survey, the respondents were asked under what conditions the United States should commit to reducing greenhouse gas emissions. 57% answered that the US should cut its emissions no matter what actions other countries take, while another 38% said that American emissions cuts would be warranted if many or all other countries commit to reducing theirs (as just happened in the Paris international negotiations).
In the 2015 survey, the number of expert economists saying that the US should cut its emissions no matter what rose to 77%. A further 18% said that if other countries agree to cut their emissions, the US should follow suit. In other words, there is a 95% consensus among expert climate economists that the US should follow through with its pledges to cut carbon pollution in the wake of the Paris international climate negotiations, and more than three out of four agreed that the US should take action to curb global warming no matter what.
2015 New York University survey results of economists with climate expertise when asked under what circumstances the USA should reduce its emissions
This expert consensus is in stark contrast to conservative political opposition to the Paris accord. For example, Republican presidential candidate Marco Rubio said of the agreement,
This kind of unilateral disarmament in our economy is reckless, and it is hurting the American Dream
Quite obviously an international agreement made by 195 nations around the world is the antithesis of unilateral action. However, 77% of expert economists agree that unilateral action would be appropriate in any case, directly contradicting Rubio’s comments. Additionally, 82% of the experts agreed that by implementing climate policies, the US could strategically induce other countries to cut their carbon pollution.
Climate change is already hurting the global economy
When asked at what date climate change will have a net negative impact on the global economy, the median survey response was 2025. In the recent past, climate change likely had a net positive impact on the global economy, due primarily to the effect of carbon fertilization on crops and other plant life. However, even contrarian economists agree, when accounting for the vulnerability of poorer countries to climate impacts, global warming has been hurting the global economy since about 1980.
The NYU survey asked when the economic benefits we experienced up to 1980 would be completely wiped out; 41% of respondents said that’s already happened. Another 25% answered that it would happen within a decade, and 26% said we’d see net negative economic impacts by 2050. If we continue with business-as-usual pollution and warming, on average the experts predicted a GDP loss of about 10% by the end of the century, and that there would be a 20% chance of a “catastrophic” loss of one-quarter of global GDP.
Figure 5 from ‘Expert Consensus on the Economics of Climate Change’ 2015 report by the NYU Institute for Policy Integrity.
Of course, ideally we would have stopped warming the planet in 1980 to preserve the economic benefits of global warming to that date. At this point it’s a question of just how much damage climate change will do to the global economy, and the economic experts are worried that the results could be catastrophic.
Climate change will hurt economic growth
78% of the survey participants said that it’s likely (36%) or extremely likely (42%) that climate change will have a long-term negative impact on the growth rate of the global economy. That’s an important point, because most current integrated economic-climate assessment models assume that economic growth will continue regardless of climate change impacts. There’s been a growing body of research indicating that as you might expect, that won’t be the case.
The results of this survey question show that most expert economists agree, climate change will hurt global economic growth. That also suggests that past model-based studies likely significantly underestimated the costs of climate change. Along the same lines, 51% of the experts answered that the US government’s estimate for the “social cost of carbon” ($37 per metric ton), which is largely based on estimates from these models, is too low. 18% of the experts said that value is about right, and just 8% said it’s too high.
Carbon pricing is an efficient way to cut pollution
The survey also asked the experts about the most economically efficient method of reducing carbon pollution. 81% said a market-based system (carbon tax or cap and trade system) would be most efficient, while 13% answered that coordinated performance standards and programs that prioritize cleaner fuels and energy efficiency would be most efficient.
The “Autism & Beyond” app uses an iPhone’s self-facing camera to assess a child’s emotional state while viewing various stimuli. The dots are landmarks automatically placed on a video of the child by the software. (Photo from Autism & Beyond)
By Warren Duffie, Office of Naval Research
There’s an app for everything these days—from weight loss to working out. Now, thanks in part to support from the Office of Naval Research (ONR), there’s an app that may screen for autism by reading kids’ facial expressions for emotional cues.
“The long-term implications of this research are huge,” said Dr. Predrag Neskovic, a program officer in ONR’s Mathematical Data Science program. “Not only could the app be used to learn more about childhood autism, it could possibly reveal signs of post-traumatic stress disorder [PTSD] and mild traumatic brain injury [TBI] in warfighters—conditions that often have subtle symptoms and are difficult to diagnose.”
The app, called “Autism & Beyond,” was developed by researchers and software developers at Duke University and the Duke Medical Center. It currently is available for free download from the Apple App Store to families wishing to participate in a six-month medical research study by Duke University.
“Autism & Beyond” has children complete a series of questionnaires and watch short videos designed to make them smile, laugh and be surprised. Parents or caregivers use an iPhone’s user-facing “selfie” camera to record children’s facial movements for evaluation by doctors, researchers and software.
The app’s core technical component—the ONR-sponsored technology—is a complex mathematical algorithm that automatically maps key landmarks on children’s faces and assesses emotional responses based on movements of facial muscles.
“We analyze the video to track position and movement of the head and face, including the lips, eyes and nose—all of which indicate emotions,” said Dr. Guillermo Sapiro, a professor at Duke University, who developed the algorithm. “For example, while watching stimuli like a funny video, does the child smile, look toward the caregiver or ask the caregiver to view the video as well? We study all of that. Lack of emotion and social sharing are possible characteristics of childhood autism.”
Sapiro stresses the app isn’t a self-diagnosis resource, but is intended to serve as a potential screening tool for autism and other developmental challenges, and encourage users to contact a physician for specialized testing.
Once the autism studies are complete, Sapiro hopes to eventually expand and tailor the app to conditions suffered by warfighters, including PTSD, TBI and depression. As with autism, facial expressions can indicate the presence of such disorders. For example, many individuals suffering from PTSD or depression smile often, but their grins tend to be forced and short. Improved analysis of such facial expressions could lead to more accurate diagnoses by doctors and, consequently, enhanced treatment options for military personnel and veterans.
“The great thing about the algorithm and video analysis tool is they can be universally applied to various research apps and studies,” said Sapiro. “Today it’s autism, in the future it could be PTSD. How can we take ‘Autism & Beyond’ beyond its current state and to the next level? Autism is just the start.
“We hope to find the right partner and develop a research app studying PTSD,” he continued. “We’ve already received interest from a nearby Veterans Affairs center about using this technology in veterans’ homes to monitor behavior for signs of depression.”
For more about the “Autism & Beyond” study, click here. Sapiro’s research aligns with the Naval S&T Strategy, which emphasizes health and resilience as key components of warfighter performance.
Warren Duffie is a contractor for ONR Corporate Strategic Communications.
from Armed with Science http://ift.tt/1mAcyNN
The “Autism & Beyond” app uses an iPhone’s self-facing camera to assess a child’s emotional state while viewing various stimuli. The dots are landmarks automatically placed on a video of the child by the software. (Photo from Autism & Beyond)
By Warren Duffie, Office of Naval Research
There’s an app for everything these days—from weight loss to working out. Now, thanks in part to support from the Office of Naval Research (ONR), there’s an app that may screen for autism by reading kids’ facial expressions for emotional cues.
“The long-term implications of this research are huge,” said Dr. Predrag Neskovic, a program officer in ONR’s Mathematical Data Science program. “Not only could the app be used to learn more about childhood autism, it could possibly reveal signs of post-traumatic stress disorder [PTSD] and mild traumatic brain injury [TBI] in warfighters—conditions that often have subtle symptoms and are difficult to diagnose.”
The app, called “Autism & Beyond,” was developed by researchers and software developers at Duke University and the Duke Medical Center. It currently is available for free download from the Apple App Store to families wishing to participate in a six-month medical research study by Duke University.
“Autism & Beyond” has children complete a series of questionnaires and watch short videos designed to make them smile, laugh and be surprised. Parents or caregivers use an iPhone’s user-facing “selfie” camera to record children’s facial movements for evaluation by doctors, researchers and software.
The app’s core technical component—the ONR-sponsored technology—is a complex mathematical algorithm that automatically maps key landmarks on children’s faces and assesses emotional responses based on movements of facial muscles.
“We analyze the video to track position and movement of the head and face, including the lips, eyes and nose—all of which indicate emotions,” said Dr. Guillermo Sapiro, a professor at Duke University, who developed the algorithm. “For example, while watching stimuli like a funny video, does the child smile, look toward the caregiver or ask the caregiver to view the video as well? We study all of that. Lack of emotion and social sharing are possible characteristics of childhood autism.”
Sapiro stresses the app isn’t a self-diagnosis resource, but is intended to serve as a potential screening tool for autism and other developmental challenges, and encourage users to contact a physician for specialized testing.
Once the autism studies are complete, Sapiro hopes to eventually expand and tailor the app to conditions suffered by warfighters, including PTSD, TBI and depression. As with autism, facial expressions can indicate the presence of such disorders. For example, many individuals suffering from PTSD or depression smile often, but their grins tend to be forced and short. Improved analysis of such facial expressions could lead to more accurate diagnoses by doctors and, consequently, enhanced treatment options for military personnel and veterans.
“The great thing about the algorithm and video analysis tool is they can be universally applied to various research apps and studies,” said Sapiro. “Today it’s autism, in the future it could be PTSD. How can we take ‘Autism & Beyond’ beyond its current state and to the next level? Autism is just the start.
“We hope to find the right partner and develop a research app studying PTSD,” he continued. “We’ve already received interest from a nearby Veterans Affairs center about using this technology in veterans’ homes to monitor behavior for signs of depression.”
For more about the “Autism & Beyond” study, click here. Sapiro’s research aligns with the Naval S&T Strategy, which emphasizes health and resilience as key components of warfighter performance.
Warren Duffie is a contractor for ONR Corporate Strategic Communications.
“Gravitational and electromagnetic interactions are long-range interactions, meaning they act on objects no matter how far they are separated from each other.” -Francois Englert
One of the most spectacular predictions of Einstein’s General Relativity was the existence of gravitational lensing, whereby a large foreground mass could act as a lens, magnifying and distorting the background light source behind it. Although this was first observed for quasars, large galaxy clusters act as the most powerful lenses.
Image credit: K. Sharon et al., 2014, via http://ift.tt/1mKOkyw.
Which is why it was such a surprise that the brightest feature in the recently observed galaxy cluster SDSS J1531+3414 wasn’t from gravitational lensing, as originally thought, but was simply a gas bridge of star formation connecting two giant elliptical galaxies. It took redshift data for the individual components to arrive at that conclusion, showing once again that even the best experience and intuition is no substitute for good data.
Image credit: NASA, ESA, and G. Tremblay (European Southern Observatory).
“Gravitational and electromagnetic interactions are long-range interactions, meaning they act on objects no matter how far they are separated from each other.” -Francois Englert
One of the most spectacular predictions of Einstein’s General Relativity was the existence of gravitational lensing, whereby a large foreground mass could act as a lens, magnifying and distorting the background light source behind it. Although this was first observed for quasars, large galaxy clusters act as the most powerful lenses.
Image credit: K. Sharon et al., 2014, via http://ift.tt/1mKOkyw.
Which is why it was such a surprise that the brightest feature in the recently observed galaxy cluster SDSS J1531+3414 wasn’t from gravitational lensing, as originally thought, but was simply a gas bridge of star formation connecting two giant elliptical galaxies. It took redshift data for the individual components to arrive at that conclusion, showing once again that even the best experience and intuition is no substitute for good data.
Image credit: NASA, ESA, and G. Tremblay (European Southern Observatory).
Since Paul Crutzen and Eugene Stoermer introduced the word Anthropocene in 2000, scientists and nonscientists alike have used the word to highlight the concept that we are now living in a time when the global environment, at some level, is shaped by humankind rather than vice versa. Humans have significantly altered Earth’s land surface, oceans, rivers, atmosphere, flora, and fauna. By its emphasis on the here and now and on what humans have done and can do in the future, the word Anthropocene has served as a call to action for environmental sustainability and responsibility [Crutzen and Stoermer, 2000; Waters et al., 2014; Ruddiman et al., 2015].
So far, however, the term Anthropocene has not been integrated into the official Geologic Time Scale, which geologists use to divide the past into named blocks based on the rock record. In 2016 or thereabouts, the International Commission on Stratigraphy—the scientific body that maintains the official Geologic Time Scale—will consider a proposal to formalize a definition of this term.
It’s a decision that has both semantic and scientific implications and may have legal implications as well. Follow the links below to learn more:
Seven of the many concepts of the word Anthropocene (A–G) that divide this record. CE = Common Era. This is a simplified pollen/spore diagram of the record from a lake sediment core with annual layers in southern Ontario, Canada. Variations in percentage of corn pollen (labeled “corn”) and spores from a corn smut fungus serve as a proxy for human impact. Chronology comes from layer counts and radiocarbon dating.
Multiple meanings. Scientists generally agree on certain characteristics of the word Anthropocene:
It is here to stay, with more than 500,000 Google hits and growing.
It carries connotations of human dominance of the environment.
The Anthropocene is not currently a formal part of the Geologic Time Scale.
Underneath our agreements lies a major divergence in philosophy. Let’s start with a simple test. The data shown on the left in the chart above are abundances of corn pollen and corn smut spores in sediment layers in a lake in southern Ontario, Canada (although any proxy for anthropogenic influence could be used).
Can you relate your concept of the Anthropocene to a specific sedimentary record? Your answer likely reflects your views about making the Anthropocene a formal part of the Geologic Time Scale.
If you answered A, B, or C, you probably think you favor including the Anthropocene as a formal part of the Geologic Time Scale—especially if your particular choice of start date is selected. If your choice is not selected, you may not favor formalization at all.
If you answered D or E, you probably oppose formalization. The choice you made is based on cultural considerations—here with either a First Nation (D) or Eurocentric (E) emphasis. You probably don’t want a subset of geologists to co-opt the word Anthropocene for their concepts.
If you answered F or G, you probably mildly (F) or strongly (G) oppose this inclusion.
In any case, no matter how you use the term Anthropocene, others are using the same word with a very different meaning.
Contrasting philosophies. Throughout history, humans have divided time into named portions. Giving a name to something makes communication and analysis easier. For communicating time, two general philosophies are popular among various scientific disciplines.
One philosophy is to name time segments by some means of recognizing defined points in time. For example, the Victorian era can be defined precisely by the dates of the reign of Queen Victoria of England (20 June 1837 to 22 January 1901). Named intervals of time represent the same starting and ending points and are of the same duration everywhere. This precision is relatively easy when dealing with historical time; it becomes more difficult when dealing with the geologic record.
A second philosophy is to name time segments by stages in human cultural development, such as the Bronze Age and the Renaissance. The Bronze Age reflects neither a specific starting date nor a duration of a specific number of years. Rather, it begins and ends at different dates at different places on the basis of the presence or absence of specific features in the development of the civilization present in a particular place.
Geologists, like other scientists, have rules and precedents for formal nomenclature, and these are embodied in the Geologic Time Scale. The scale is tied to the rock record and took shape over centuries, often without strict definitions. Since the 1970s, however, the International Commission on Stratigraphy of the International Union of Geological Sciences has been the arbiter of the terms appearing on the Geologic Time Scale.
The Geologic Time Scale includes only those terms that, to the best of current knowledge, relate to the rock record of specific segments of geologic time. Each unit represents, conceptually, the same interval of time everywhere in the world. Although imprecision in recognizing the time signal in the rock record imposes limitations, no unit of the Geologic Time Scale is specified to have different durations in different parts of the world, and there is no geologic record of the future.
If the Anthropocene is to become a formal part of the Geologic Time Scale, a unique point in time must mark its beginning. Although it is tempting to examine at length the relative merits of various particular starting points, the real discussion should focus on a different question: Can any unique point in time coexist with current Anthropocene concepts and usage? In other words, does the Anthropocene have a beginning that is the same everywhere, or does it begin at different times in different places because it represents a holistic concept that involves time, place, human cultural attainment and dominance, and a variety of environmental effects [Edgeworth et al., 2015; Ruddiman et al., 2015]?
Hierarchy. If the Anthropocene is to be incorporated into the Geologic Time Scale, the International Commission on Stratigraphy will have to deal with the question of rank. Each unit in the time scale has a rank. Eras are divided into periods, which are divided into epochs, which are divided into ages.
A quick search in the scientific and popular literature for the term “Anthropocene” reveals an obvious lack of consensus on its rank. Hundreds of citations refer to an Anthropocene era, an Anthropocene period, an Anthropocene epoch, and an Anthropocene age. In fact, the term “Anthropocene” is so widely employed that many users must be quite unaware of the formal rank terms of geologists.
Rank has consequences. If the rank of era is appropriate for the Anthropocene, the direct corollary is that the Cenozoic era, which began approximately 66 million years ago with the demise of the nonavian dinosaurs, has ended. If the Anthropocene is a period, then the Quaternary period, which began approximately 2.6 million years ago at a time of major glacial-interglacial fluctuation, has ended. If it is an epoch, then the Holocene epoch – the interglacial (warm) interval that began 11,800 years ago – has ended. If it is an age, then it is the current age within the Holocene epoch.
These consequences extend far beyond the scientific community. For instance, many building codes have strict legal definitions of what constitutes a “Holocene fault.” If the Holocene epoch were to be over, perhaps a developer would try to build in an area of active ground movement because, technically, there is no Holocene fault. Or would “Holocene” have two meanings: one geological, one legal?
If the Anthropocene is formally defined as a geological epoch beginning in 1945, then newer structures – such as the Grant Marsh Interstate 94 bridge over the Missouri River in Bismarck, N.D. (foreground) – would be classified as Anthropocene. Older structures with or without recent updates, such as the Bismarck railroad bridge (center) would be classified as Holocene and Anthropocene. Photo via Joel M. Galloway, USGS
Possible outcomes. The International Commission on Stratigraphy has set a target date in 2016 for consideration of a proposal to formalize the Anthropocene. I see three possible outcomes:
1. The word Anthropocene will be assigned a specific start time (which will not please everyone) and will be added to the formal Geologic Time Scale. In this case, the word Anthropocene will not have a 1:1 correspondence with any and all things anthropogenic. If the Anthropocene is assigned the rank of epoch, then the Holocene is over. Rigorously applied labels such as Holocene and Anthropocene will be used in all discussions of anthropogenic deposits or anthropogenic environmental effects that originate before the chosen start time.
2. The word Anthropocene will be used in a cultural sense to indicate and call attention to the fact that humankind significantly influences the global environment. It will represent a holistic concept and may have different start times in different places in the world. It may depend on different features or environmental effects. Deposits of anthropogenic origin will be considered Anthropocene deposits. The Anthropocene can easily be depicted on the formal Geologic Time Scale but will not be a formal unit of it. Some people may consider the Anthropocene to be an informal unit of geologic time. Others may not consider it a time unit at all.
3. The word Anthropocene will be assigned a specific start time and placed on the formal Geologic Time Scale, but a significant proportion of its use would be in direct contradiction of the basic tenets of stratigraphic correlation and terminology. Many scientists will now say that it is acceptable to have an Anthropocene epoch that is openly acknowledged to vary in age from place to place. These scientists will include those who in the past have recognized that chronostratigraphic correlation (although never perfect) strives to recognize time equivalence. The term will be used by all but strict-constructionist stratigraphers in a variety of ways to mean different things to different people, most of them thinking that their way is formal and correct.
In the next year or so, the International Commission on Stratigraphy will make a decision, and the rest of us will have to live with it. Is the Anthropocene a specific subdivision in the continuum of time, or is it a holistic concept that includes time but is not defined by it? Which decision will serve us best?
Bottom line: Re-print of an article from Eos in late 2015, by Lucy E. Edwards, discussing the upcoming decision by the International Commission on Stratigraphy on whether the word “Anthropocene” should be formally included in the Geologic Time Scale. Article used with permission.
from EarthSky http://ift.tt/1IMaXiv
Image from a film called Welcome to the Anthropocene, commissioned by the Planet Under Pressure conference, London, March, 2012.
Since Paul Crutzen and Eugene Stoermer introduced the word Anthropocene in 2000, scientists and nonscientists alike have used the word to highlight the concept that we are now living in a time when the global environment, at some level, is shaped by humankind rather than vice versa. Humans have significantly altered Earth’s land surface, oceans, rivers, atmosphere, flora, and fauna. By its emphasis on the here and now and on what humans have done and can do in the future, the word Anthropocene has served as a call to action for environmental sustainability and responsibility [Crutzen and Stoermer, 2000; Waters et al., 2014; Ruddiman et al., 2015].
So far, however, the term Anthropocene has not been integrated into the official Geologic Time Scale, which geologists use to divide the past into named blocks based on the rock record. In 2016 or thereabouts, the International Commission on Stratigraphy—the scientific body that maintains the official Geologic Time Scale—will consider a proposal to formalize a definition of this term.
It’s a decision that has both semantic and scientific implications and may have legal implications as well. Follow the links below to learn more:
Seven of the many concepts of the word Anthropocene (A–G) that divide this record. CE = Common Era. This is a simplified pollen/spore diagram of the record from a lake sediment core with annual layers in southern Ontario, Canada. Variations in percentage of corn pollen (labeled “corn”) and spores from a corn smut fungus serve as a proxy for human impact. Chronology comes from layer counts and radiocarbon dating.
Multiple meanings. Scientists generally agree on certain characteristics of the word Anthropocene:
It is here to stay, with more than 500,000 Google hits and growing.
It carries connotations of human dominance of the environment.
The Anthropocene is not currently a formal part of the Geologic Time Scale.
Underneath our agreements lies a major divergence in philosophy. Let’s start with a simple test. The data shown on the left in the chart above are abundances of corn pollen and corn smut spores in sediment layers in a lake in southern Ontario, Canada (although any proxy for anthropogenic influence could be used).
Can you relate your concept of the Anthropocene to a specific sedimentary record? Your answer likely reflects your views about making the Anthropocene a formal part of the Geologic Time Scale.
If you answered A, B, or C, you probably think you favor including the Anthropocene as a formal part of the Geologic Time Scale—especially if your particular choice of start date is selected. If your choice is not selected, you may not favor formalization at all.
If you answered D or E, you probably oppose formalization. The choice you made is based on cultural considerations—here with either a First Nation (D) or Eurocentric (E) emphasis. You probably don’t want a subset of geologists to co-opt the word Anthropocene for their concepts.
If you answered F or G, you probably mildly (F) or strongly (G) oppose this inclusion.
In any case, no matter how you use the term Anthropocene, others are using the same word with a very different meaning.
Contrasting philosophies. Throughout history, humans have divided time into named portions. Giving a name to something makes communication and analysis easier. For communicating time, two general philosophies are popular among various scientific disciplines.
One philosophy is to name time segments by some means of recognizing defined points in time. For example, the Victorian era can be defined precisely by the dates of the reign of Queen Victoria of England (20 June 1837 to 22 January 1901). Named intervals of time represent the same starting and ending points and are of the same duration everywhere. This precision is relatively easy when dealing with historical time; it becomes more difficult when dealing with the geologic record.
A second philosophy is to name time segments by stages in human cultural development, such as the Bronze Age and the Renaissance. The Bronze Age reflects neither a specific starting date nor a duration of a specific number of years. Rather, it begins and ends at different dates at different places on the basis of the presence or absence of specific features in the development of the civilization present in a particular place.
Geologists, like other scientists, have rules and precedents for formal nomenclature, and these are embodied in the Geologic Time Scale. The scale is tied to the rock record and took shape over centuries, often without strict definitions. Since the 1970s, however, the International Commission on Stratigraphy of the International Union of Geological Sciences has been the arbiter of the terms appearing on the Geologic Time Scale.
The Geologic Time Scale includes only those terms that, to the best of current knowledge, relate to the rock record of specific segments of geologic time. Each unit represents, conceptually, the same interval of time everywhere in the world. Although imprecision in recognizing the time signal in the rock record imposes limitations, no unit of the Geologic Time Scale is specified to have different durations in different parts of the world, and there is no geologic record of the future.
If the Anthropocene is to become a formal part of the Geologic Time Scale, a unique point in time must mark its beginning. Although it is tempting to examine at length the relative merits of various particular starting points, the real discussion should focus on a different question: Can any unique point in time coexist with current Anthropocene concepts and usage? In other words, does the Anthropocene have a beginning that is the same everywhere, or does it begin at different times in different places because it represents a holistic concept that involves time, place, human cultural attainment and dominance, and a variety of environmental effects [Edgeworth et al., 2015; Ruddiman et al., 2015]?
Hierarchy. If the Anthropocene is to be incorporated into the Geologic Time Scale, the International Commission on Stratigraphy will have to deal with the question of rank. Each unit in the time scale has a rank. Eras are divided into periods, which are divided into epochs, which are divided into ages.
A quick search in the scientific and popular literature for the term “Anthropocene” reveals an obvious lack of consensus on its rank. Hundreds of citations refer to an Anthropocene era, an Anthropocene period, an Anthropocene epoch, and an Anthropocene age. In fact, the term “Anthropocene” is so widely employed that many users must be quite unaware of the formal rank terms of geologists.
Rank has consequences. If the rank of era is appropriate for the Anthropocene, the direct corollary is that the Cenozoic era, which began approximately 66 million years ago with the demise of the nonavian dinosaurs, has ended. If the Anthropocene is a period, then the Quaternary period, which began approximately 2.6 million years ago at a time of major glacial-interglacial fluctuation, has ended. If it is an epoch, then the Holocene epoch – the interglacial (warm) interval that began 11,800 years ago – has ended. If it is an age, then it is the current age within the Holocene epoch.
These consequences extend far beyond the scientific community. For instance, many building codes have strict legal definitions of what constitutes a “Holocene fault.” If the Holocene epoch were to be over, perhaps a developer would try to build in an area of active ground movement because, technically, there is no Holocene fault. Or would “Holocene” have two meanings: one geological, one legal?
If the Anthropocene is formally defined as a geological epoch beginning in 1945, then newer structures – such as the Grant Marsh Interstate 94 bridge over the Missouri River in Bismarck, N.D. (foreground) – would be classified as Anthropocene. Older structures with or without recent updates, such as the Bismarck railroad bridge (center) would be classified as Holocene and Anthropocene. Photo via Joel M. Galloway, USGS
Possible outcomes. The International Commission on Stratigraphy has set a target date in 2016 for consideration of a proposal to formalize the Anthropocene. I see three possible outcomes:
1. The word Anthropocene will be assigned a specific start time (which will not please everyone) and will be added to the formal Geologic Time Scale. In this case, the word Anthropocene will not have a 1:1 correspondence with any and all things anthropogenic. If the Anthropocene is assigned the rank of epoch, then the Holocene is over. Rigorously applied labels such as Holocene and Anthropocene will be used in all discussions of anthropogenic deposits or anthropogenic environmental effects that originate before the chosen start time.
2. The word Anthropocene will be used in a cultural sense to indicate and call attention to the fact that humankind significantly influences the global environment. It will represent a holistic concept and may have different start times in different places in the world. It may depend on different features or environmental effects. Deposits of anthropogenic origin will be considered Anthropocene deposits. The Anthropocene can easily be depicted on the formal Geologic Time Scale but will not be a formal unit of it. Some people may consider the Anthropocene to be an informal unit of geologic time. Others may not consider it a time unit at all.
3. The word Anthropocene will be assigned a specific start time and placed on the formal Geologic Time Scale, but a significant proportion of its use would be in direct contradiction of the basic tenets of stratigraphic correlation and terminology. Many scientists will now say that it is acceptable to have an Anthropocene epoch that is openly acknowledged to vary in age from place to place. These scientists will include those who in the past have recognized that chronostratigraphic correlation (although never perfect) strives to recognize time equivalence. The term will be used by all but strict-constructionist stratigraphers in a variety of ways to mean different things to different people, most of them thinking that their way is formal and correct.
In the next year or so, the International Commission on Stratigraphy will make a decision, and the rest of us will have to live with it. Is the Anthropocene a specific subdivision in the continuum of time, or is it a holistic concept that includes time but is not defined by it? Which decision will serve us best?
Bottom line: Re-print of an article from Eos in late 2015, by Lucy E. Edwards, discussing the upcoming decision by the International Commission on Stratigraphy on whether the word “Anthropocene” should be formally included in the Geologic Time Scale. Article used with permission.
The discrepancy between the clock and sun gives us the latest sunrises after the winter solstice for mid-latitudes in the Northern Hemisphere. Photo credit: Amika Malone
So you like to sleep late but don’t want to miss the sunrise or the morning planets? (Scroll down to see the chart of the morning planets.) This time of year should be your favorite. Sleep on – if you live in the Northern Hemisphere. The latest sunrises of 2016 – for mid-latitudes in the Northern Hemisphere – are happening around now. For example, sunrise time in the central U.S. – say, around Wichita, Kansas – for the next several days will be around 7:45 in the morning. Meanwhile, if you live in the Southern Hemisphere, your latest sunsets are happening around now, assuming you’re at mid-southern latitudes.
Many sky watchers notice this phenomenon, which is part of an unvarying sequence each year. For us at mid-northern latitudes in the Northern Hemisphere, the sequence is: earliest sunset in early December, shortest day at the solstice around December 21, latest sunrise in early January. At middle latitudes in the Southern Hemisphere, the sequence is: earliest sunrise in early December, longest day at the December solstice, latest sunset in early January. This natural order is part of what we can expect, every year, from nature.
The December solstice always brings the shortest day to the Northern Hemisphere and the longest day to the Southern Hemisphere. But, clearly, the latest sunrise doesn’t coincide with the day of least daylight, and the latest sunset doesn’t happen on the day of greatest daylight. Why not?
The main reason is that the Earth’s rotational axis is tilted 23.5o out of vertical to the plane of our orbit around the sun. A secondary reason is that the Earth’s orbit isn’t a perfect circle. Due to our eccentric orbit (that’s an orbit shaped like a squashed circle, with the sun slightly off its center), Earth travels fastest in January and slowest in July. Clock time gets a bit out of sync with sun time – by about the tune of 1/2 minute per day for several weeks around the December solstice.
Because solar noon (midday) comes later by the clock today than on the solstice, so do the times of sunrise and sunset. The table below helps to explain:
For Philadelphia, Pennsylvania
Date
Sunrise
Solar Noon (Midday)
Sunset
Daylight Hours
December 7
7:09 a.m.
11:52 a.m.
4:35 p.m.
9 hours 27 minutes
December 21
7:19 a.m.
11:59 a.m.
4:39 p.m.
9 hours 20 minutes
January 5
7:23 a.m.
12:06 p.m.
4:49 p.m.
9 hours 27 minutes
The exact date for the latest sunrise or latest sunset varies by latitude. At present, mid-temperate latitudes in the Northern Hemisphere have their latest sunrises, while the Southern Hemisphere’s mid-temperate latitudes are watching their latest sunsets. At latitudes closer to the equator, the latest sunrise or latest sunset has yet to come. Closer to the Arctic and Antarctic Circles, the latest sunrise and latest sunset have already come and gone.
But in either the Northern or Southern Hemisphere, the sequence is always the same:
The approximate positions of the morning planets in early January 2016. Saturn will actually climb above Venus on or near January 9. The green line depicts the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac. Read more
Bottom line: Notice the time of sunrise and sunset at this time of year. If you’re in the Northern Hemisphere, your latest sunrises are happening around now at mid-northern latitudes. If you’re in the Southern Hemisphere, mid-latitudes are watching the year’s latest sunsets. Enjoy them!
The discrepancy between the clock and sun gives us the latest sunrises after the winter solstice for mid-latitudes in the Northern Hemisphere. Photo credit: Amika Malone
So you like to sleep late but don’t want to miss the sunrise or the morning planets? (Scroll down to see the chart of the morning planets.) This time of year should be your favorite. Sleep on – if you live in the Northern Hemisphere. The latest sunrises of 2016 – for mid-latitudes in the Northern Hemisphere – are happening around now. For example, sunrise time in the central U.S. – say, around Wichita, Kansas – for the next several days will be around 7:45 in the morning. Meanwhile, if you live in the Southern Hemisphere, your latest sunsets are happening around now, assuming you’re at mid-southern latitudes.
Many sky watchers notice this phenomenon, which is part of an unvarying sequence each year. For us at mid-northern latitudes in the Northern Hemisphere, the sequence is: earliest sunset in early December, shortest day at the solstice around December 21, latest sunrise in early January. At middle latitudes in the Southern Hemisphere, the sequence is: earliest sunrise in early December, longest day at the December solstice, latest sunset in early January. This natural order is part of what we can expect, every year, from nature.
The December solstice always brings the shortest day to the Northern Hemisphere and the longest day to the Southern Hemisphere. But, clearly, the latest sunrise doesn’t coincide with the day of least daylight, and the latest sunset doesn’t happen on the day of greatest daylight. Why not?
The main reason is that the Earth’s rotational axis is tilted 23.5o out of vertical to the plane of our orbit around the sun. A secondary reason is that the Earth’s orbit isn’t a perfect circle. Due to our eccentric orbit (that’s an orbit shaped like a squashed circle, with the sun slightly off its center), Earth travels fastest in January and slowest in July. Clock time gets a bit out of sync with sun time – by about the tune of 1/2 minute per day for several weeks around the December solstice.
Because solar noon (midday) comes later by the clock today than on the solstice, so do the times of sunrise and sunset. The table below helps to explain:
For Philadelphia, Pennsylvania
Date
Sunrise
Solar Noon (Midday)
Sunset
Daylight Hours
December 7
7:09 a.m.
11:52 a.m.
4:35 p.m.
9 hours 27 minutes
December 21
7:19 a.m.
11:59 a.m.
4:39 p.m.
9 hours 20 minutes
January 5
7:23 a.m.
12:06 p.m.
4:49 p.m.
9 hours 27 minutes
The exact date for the latest sunrise or latest sunset varies by latitude. At present, mid-temperate latitudes in the Northern Hemisphere have their latest sunrises, while the Southern Hemisphere’s mid-temperate latitudes are watching their latest sunsets. At latitudes closer to the equator, the latest sunrise or latest sunset has yet to come. Closer to the Arctic and Antarctic Circles, the latest sunrise and latest sunset have already come and gone.
But in either the Northern or Southern Hemisphere, the sequence is always the same:
The approximate positions of the morning planets in early January 2016. Saturn will actually climb above Venus on or near January 9. The green line depicts the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac. Read more
Bottom line: Notice the time of sunrise and sunset at this time of year. If you’re in the Northern Hemisphere, your latest sunrises are happening around now at mid-northern latitudes. If you’re in the Southern Hemisphere, mid-latitudes are watching the year’s latest sunsets. Enjoy them!
January 4, 1643. English physicist and mathematician Isaac Newton was born on this date. He is remembered as one of the world’s greatest scientists, because his insights laid a foundation for our understanding of celestial motion, light and gravity.
Newton’s work in three famous volumes comprise the Philosophae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), often referred to as simply the Principia. In this work, Newton states his three laws of motion, which today form the foundation of classical celestial mechanics. The Principia also lays out Newton’s revelations about gravity.
By all accounts, Newton’s Principia is a masterpiece. Read more about his work by clicking the links below.
Newton’s three Laws of Motion. They’re called laws, but they are really descriptions of fundamental truths about our physical universe.
1. An object at rest will remain at rest unless acted on by an outside force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an outside force. This law is often called the law of inertia. Click here to read more about Newton’s First Law of Motion.
Newton’s revelations about gravity. Remember the story of the apple falling on Newton’s head? While not necessarily true in all its details, Newton apparently observed an apple fall from a tree and began thinking that, in order to fall on the ground, the apple was accelerated from zero when it hung on the tree.
According to his Second Law of Motion, acceleration is produced when a force acts on an object. Newton must have thought, what is that force? He came to understand this force as what every school child today knows as gravity.
Newton’s great revelation was that the force of gravity doesn’t just extend to the tops of apple trees. If an apple tree were as high as a mountain, for example, the apple would still fall. The force would still be operating. Newton’s insight was that the force of gravity extends much further … to the moon. He recognized that the orbit of the moon around Earth is a consequence of the force of gravity.
Others who followed Newton – most particularly Albert Einstein – refined our understanding of gravity. The most accurate description of gravity today can be found in Einstein’s general theory of relativity, which asserts that gravity is a consequence of the curvature of space-time.
Fascinated by Newton’s revelations about gravity? Check out this 15-minute video:
If Newton had only contributed his three Laws of Motion and his understanding of universal gravitation, we’d have remembered him as one of the world’s greatest scientists. But Newton didn’t stop there. He also built one of the first practical reflecting telescopes, contributed to the invention of calculus, and explored how white light can be broken up into a spectrum of colors by a prism, thereby laying the foundation for much of modern astronomy.
Yet Newton himself knew how much more remained to be discovered. He is known to have said:
I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.
By the way, in the past, you often saw Newton’s birthday as December 25, 1642. That is beginning to change, and now we are more and more often seeing Newton’s birthday as January 4, 1643. The difference is due to the fact that, when Newton was born, England was in the midst of a 150-year period of using a different calendar from the rest of Europe. The rest of the continent had already adopted the Gregorian calendar – same calendar we today use. However, the English were still using the Julian calendar, which lagged ten days behind because of a faulty method of accounting for leap years.
Bottom line: Isaac Newton was born on January 4, 1643 (December 25, 1642, in the same year that Galileo died, in the old style Gregorian calendar). His work laid much of the foundation for our modern understanding of the physical universe.
from EarthSky http://ift.tt/1Bljwdd
January 4, 1643. English physicist and mathematician Isaac Newton was born on this date. He is remembered as one of the world’s greatest scientists, because his insights laid a foundation for our understanding of celestial motion, light and gravity.
Newton’s work in three famous volumes comprise the Philosophae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), often referred to as simply the Principia. In this work, Newton states his three laws of motion, which today form the foundation of classical celestial mechanics. The Principia also lays out Newton’s revelations about gravity.
By all accounts, Newton’s Principia is a masterpiece. Read more about his work by clicking the links below.
Newton’s three Laws of Motion. They’re called laws, but they are really descriptions of fundamental truths about our physical universe.
1. An object at rest will remain at rest unless acted on by an outside force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an outside force. This law is often called the law of inertia. Click here to read more about Newton’s First Law of Motion.
Newton’s revelations about gravity. Remember the story of the apple falling on Newton’s head? While not necessarily true in all its details, Newton apparently observed an apple fall from a tree and began thinking that, in order to fall on the ground, the apple was accelerated from zero when it hung on the tree.
According to his Second Law of Motion, acceleration is produced when a force acts on an object. Newton must have thought, what is that force? He came to understand this force as what every school child today knows as gravity.
Newton’s great revelation was that the force of gravity doesn’t just extend to the tops of apple trees. If an apple tree were as high as a mountain, for example, the apple would still fall. The force would still be operating. Newton’s insight was that the force of gravity extends much further … to the moon. He recognized that the orbit of the moon around Earth is a consequence of the force of gravity.
Others who followed Newton – most particularly Albert Einstein – refined our understanding of gravity. The most accurate description of gravity today can be found in Einstein’s general theory of relativity, which asserts that gravity is a consequence of the curvature of space-time.
Fascinated by Newton’s revelations about gravity? Check out this 15-minute video:
If Newton had only contributed his three Laws of Motion and his understanding of universal gravitation, we’d have remembered him as one of the world’s greatest scientists. But Newton didn’t stop there. He also built one of the first practical reflecting telescopes, contributed to the invention of calculus, and explored how white light can be broken up into a spectrum of colors by a prism, thereby laying the foundation for much of modern astronomy.
Yet Newton himself knew how much more remained to be discovered. He is known to have said:
I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.
By the way, in the past, you often saw Newton’s birthday as December 25, 1642. That is beginning to change, and now we are more and more often seeing Newton’s birthday as January 4, 1643. The difference is due to the fact that, when Newton was born, England was in the midst of a 150-year period of using a different calendar from the rest of Europe. The rest of the continent had already adopted the Gregorian calendar – same calendar we today use. However, the English were still using the Julian calendar, which lagged ten days behind because of a faulty method of accounting for leap years.
Bottom line: Isaac Newton was born on January 4, 1643 (December 25, 1642, in the same year that Galileo died, in the old style Gregorian calendar). His work laid much of the foundation for our modern understanding of the physical universe.
