Tag: earth problems

Caribbean 7.7 Quake: Two Terrible Myths And One Great Piece Of Advice

Shaken, not stirred.

As plenty of you have likely noticed, a rather powerful magnitude 7.7 earthquake took place underwater, 10 kilometres (6.2 miles) beneath the seafloor, northwest of Jamaica and south of Cuba on Tuesday 28th. What is for now the mainshock in the sequence – the most powerful in a series of earthquakes – the 7.7 temblor was intense enough for its shaking to be felt all over the region, even as far as Miami, 710 kilometres (441 miles) away from the epicentre.

A few hours later, a magnitude 6.5 quake took place a little closer to the Cayman Islands, likely a potent aftershock of the 7.7 mainshock. Plenty of aftershocks will continue to rock the region for several weeks or months, with a small but non-zero chance that an earthquake more powerful than the current mainshock may also take place in the area.

Fortunately, despite some infrastructural damage in spots around the region, and the initial tsunami warning, this turned out to be nothing close to a tragedy. Apart from the fact that this earthquake took place a decent enough distance from settlements, the fault that ruptured was a strike-slip variety, wherein one ‘block’ moves sideways with respect to another. This normally doesn’t permit the mass movement of significant volumes of water – i.e. a tsunami – although there are some exceptions to this. In this case, no such hazardous tsunami was reported anywhere.

As with all powerful earthquakes, a few myths and pieces of misinformation skittered about online shortly after it happened. Right at the end of 2019, I put together a piece outlining some of the commonest, aggravating and sometimes downright dangerous misconceptions about major geological events – and surprise surprise, several of them reared their heads yet again during yesterday’s earthquake and tsunami scare.

First misconception: “Wow, this earthquake took place really close to the ones afflicting Puerto Rico at the moment. They must be connected, and I bet they’re going to trigger all kinds of earthquakes now around the Ring of Fire!”

Nope. The Ring of Fire doesn’t overlap with any of the quakes or fault lines within the Caribbean Sea, which contains Puerto Rico, Cuba and Jamaica, along with a myriad of other islands and several of the shorelines of Central and South American countries. The Ring of Fire is over in the Pacific, not the Atlantic. So there’s that. At least get your geography right.

In any event, the Ring of Fire is silly. This loop, which surrounds much of the vast Pacific Ocean, features constantly shifting, sliding and grinding plate boundaries, all with their own network of segregated or closely spaced faults. This continuous activity means that 75 percent of the world’s (known) volcanic activity and 90 percent of the world’s earthquakes take place along it.

Once more, for the people at the back: none of the eruptions that take place on the Ring of Fire are related to each other. And for the most part, none of the earthquakes are either. (There is a chance that some earthquakes can trigger volcanic eruptions if they are literally right on top of one another, but this is a very contentious subject with no concrete answers available at present.) It is a designation that really doesn’t make sense, geologically speaking.

If two faults are close enough, a powerful earthquake on one can trigger an earthquake on another. In this case, the rule doesn’t apply, even though both earthquake sequences – Puerto Rico and Jamaica/Cuba/Cayman Islands – are taking place in the same sea. The general rule of thumb is that this triggering mechanism only applies when the second fault is no further away than three to four times the length of the original fault that ruptured.

As Caltech seismologist Lucy Jones took to Twitter to explain, the Puerto Rico mainshock took place on a 24-kilometre (15-mile)-long fault. That 7.7 quake yesterday was more than 1,300 kilometres (800 miles) away, or 53 times the distance of the fault that ruptured near Puerto Rico. There is no way these two earthquake sequences are connected.

Second misconception: “There are a lot of earthquakes happening around the world at the moment, right?”

Nope. Earthquakes happen around the world on all flavours of fault lines in an essentially randomised manner. Most never get reported on, because they are too weak to be felt or, even if they could be felt, are too far away from human populations to cause any damage, or at least any significant damage.

Puerto Rico’s earthquakes have been making the news because they have produced intense enough shaking to cause damage and some deaths. Yesterday’s earthquake made headlines because it was very powerful, close to major population centres, and came with a potential tsunami risk. If both happened in the middle of nowhere with no tsunami risk, they wouldn’t have made the news.

More powerful earthquakes also happen far less frequently than less powerful ones. In the past 24 hours alone, there have been 137 earthquakes detected coming in at or above a magnitude 1.5. In the past week? 1,350 of them. This is all completely normal, and the vast majority of these haven’t made the news. The ones that did were, once again, the powerful ones that may have, or did, pose a risk to human populations.

The Earth is rocking no more, or less, than it was a year, decade, century or millennium ago. Don’t let the way it’s reported in the media distort that set-in-stone fact.

Amidst all this bemusement, a piece of advice from Susan Hough, a seismologist with the U.S. Geological Survey, stood out. Even though there was no tsunami accompanying this latest Caribbean temblor, and even though there was unlikely to be one, if those on the shorelines felt strong shaking, they should – no matter what, even if there aren’t sirens or alerts – have headed to higher ground.

Tsunami warnings are not always that precise, nor are they able to be given with sufficient time to trigger appropriate evacuations. The lethal Sulawesi tsunami in Indonesia in 2018 occurred on another strike-slip fault within a bay; compared to deep-sea tsunamis, it was able to slam into densely populated coastlines within a fraction of the time. Earthquakes were detected the moment they occurred, but the unique geography of the narrow bay produced a far more devastating tsunami that the strike-slip rupture otherwise would have done. This underestimation by the local authorities was combined with another problem: several cellphone towers were downed due to the quake, meaning that tsunami alerts were not sent out to all vulnerable populations. Thousands of people perished that day.

Crucially, strong shaking was felt on several coastlines within the bay prior to the tsunami’s arrival. And thus the mantra still stands: no matter what warning you have or haven’t got, and no matter what anyone else around you is or isn’t doing, if you feel strong shaking on a beach, get to higher ground.

Follow me on Twitter.

Robin Andrews

Robin George Andrews is a doctor of experimental volcanology-turned-science journalist. He tends to write about the most extravagant of scientific tales, from eruptions and hurricanes to climate change and diamond-rich meteorites from destroyed alien worlds – but he’s always partial to a bit of pop culture science. Apart from Forbes, his work has appeared in The Atlantic, National Geographic, Scientific American, The New York Times, The Verge, Atlas Obscura, Gizmodo, WIRED and others. You can get in touch with him at robingeorgeandrews.com.

Source: Caribbean 7.7 Quake: Two Terrible Myths And One Great Piece Of Advice

Mystery Sounds From Storms Could Help Predict Tornadoes

Mysterious rumbles that herald tornadoes could one day be used to predict when and where they will strike, according to researchers.

Storms emit sounds before tornadoes form, but the signals at less than 20Hz are below the limit for human hearing. What causes these rumbles has also been a conundrum.

Now researchers said they have narrowed down the reasons for the sounds – an important factor in harnessing the knowledge to improve warnings.

“The three possibilities are core oscillations [in the tornado], pressure relaxation, and latent heat effects,” said Dr Brian Elbing, of Oklahoma State University, who is part of the team behind the research. “They are all possibilities because what we have seen is that the signal occurs before the tornado touches the ground, continues after it touches the ground, and then disappears some time after the tornado leaves the ground.”

The latest work was presented at the annual meeting of the American Physical Society’s Division of Fluid Dynamics in Seattle.

The low-frequency sound produced by tornadoes has been known about for several decades, but Elbing said a big problem has been a lack of understanding of what causes the sounds, and difficulties in unpicking them from a tornado and other aspects of the weather.

The subject has seen renewed interest in recent years, with Elbing saying it could prove particularly useful for hilly areas such as Dixie Alley, which stretches from Texas to North Carolina. “Infrasound doesn’t need line of sight like radar, so there is hope that this could significantly improve warnings in Dixie Alley where most deaths [from tornadoes] occur,” he said.

The team’s setup involves a microphone capable of picking up low-frequency sounds sealed inside a dome which has four openings at right angles to each other, each of which is attached to a hose. Three of these domes are arranged in an equilateral triangle, 60 metres away from each other.

The team say the setup allows them to filter out sounds from normal windand work out which direction the twister is travelling, while the signal itself offers an idea of the tornado’s size: a frequency of 1Hz indicates a very large tornado, while a 10Hz indicates a small one.

In their latest work, Elbing and colleagues reported a case in Oklahoma in which they were able to pick up audio clues eight minutes before the twister formed, with a clear signal detected four minutes before it hit the ground. That, they say, is important as the tornado was not picked up by radar.

“There is evidence that the amount of lead time before the tornado is dependent on how large the tornado is,” said Elbing, adding that low-frequency sounds have been detected up to two hours before a tornado forms. “This tornado we detected was very small, there was no warning issued for this tornado … which is why even a four-minute warning is a big deal.”

While the Oklahoma tornado was only 12 miles from the setup, Elbing said once the sound signal was better understood, the technique could be used over even greater distances.

“If we know the acoustic signature of a tornado, it is realistic to expect to detect a tornado from over 100 miles,” he said.

Dr Harold Brooks, a tornado expert at the US National Oceanic and Atmospheric Administration who was not involved in the work, said many questions needed to be answered before the approach could be harnessed, including whether all tornadoes make such sounds, whether such sounds can be made from other storms, and how accurate the approach is.

“No system will be perfect so there will be errors of missed events and false alarms,” said Brooks, adding that it is also not clear how many microphone arrangements would be needed to offer good coverage, saying that since the approach was based on sound waves rather than light waves, a far smaller area can be examined by each system in a given time than for radar.

“At this point it is a really intriguing thing, but there is a lot more work that needs to be done in terms of a relatively large scale experiment to actually test it,” he said.

By: @NicolaKSDavis

Source: Mystery sounds from storms could help predict tornadoes

102K subscribers
Are your kids wondering: “Why are tornadoes so hard to predict?” This question came from Hai Ming, a 2nd Grader from the US. Like, share and vote on next week’s question here: https://mysterydoug.com/vote

In 2020 Climate Science Needs To Hit The Reset Button, Part One

In a remarkable essay last week titled, “We’re Getting a Clearer Picture of the Climate Future — and It’s Not as Bad as It Once Looked,” David Wallace-Wells of New York Magazine wrote, “the climate news might be better than you thought. It’s certainly better than I’ve thought.” The essay was remarkable because Wells, a self-described “alarmist,” is also the author of The Uninhabitable Earth, which describes an apocalyptic vision of the future, dominated by “elements of climate chaos.”

According to Wallace-Wells, his new-found optimism was the result of learning that much discussion of climate change is based on extreme but implausible scenarios of the future where the world burns massive amounts of coal. The implausibility of such scenarios is underscored by more recent assessments of global energy system trajectories of the International Energy Agency and United Nations, which suggest that carbon dioxide emissions from the burning of fossil fuels will be relatively flat over the next several decades, even before aggressive climate policies are implemented.

Scenarios of the future have long sat at the center of discussions of climate science, impacts and adaptation and mitigation policies. Scenario planning has a long history and can be traced to the RAND Corporation during World War 2 and, later (ironically enough) Shell, a fossil fuel company. Scenarios are not intended to be forecasts of the future, but rather to serve as an alternative to forecasting. Scenarios provide a description of possible futures contingent upon various factors, only some of which might be under the control of decision makers.

The climate community got off track by forgetting the distinction between using scenarios as an exploratory tool for developing and evaluating policy options, and using scenarios as forecasts of where the world is headed. The scenario (or more precisely, the set of scenarios) that the climate community settled on as a baseline future for projecting future climate impacts and evaluating policy options biases how we think about climate impacts and policy responses. The point is not that climate analysts should have chosen a more realistic future as a baseline expectation, but rather, they should never have chosen a particular subset of futures for such a baseline.

The desire to predict the future is perfectly understandable. In climate science, scenarios were transformed from alternative visions of possible futures to a subset of predicted futures through the invention of a concept called “business as usual.”

The Intergovernmental Panel on Climate Change explains that “business as usual” is “synonymous” with concepts such as “baseline scenario” or “reference scenario” or “no-policy scenario.” The IPCC used of the concept of “business as usual” (and equivalencies) in the 1990s, and then explicitly rejected it in the 2000s. It has returned with a vengeance in the 2010s. A reset is needed for the 2020s.

According to the IPCC, a “baseline” scenario refers to “the state against which change is measured” and for climate impacts and policy, is “based on the assumption that no mitigation policies or measures will be implemented beyond those that are already in force and/or are legislated or planned to be adopted.” The use of such a baseline is far more important for research on climate impacts and policy than it is for most research on the physical science of climate, as the latter need not necessarily be tied to socio-economic scenarios.

The IPCC warns, quite appropriately, “Baseline scenarios are not intended to be predictions of the future, but rather counterfactual constructions that can serve to highlight the level of emissions that would occur without further policy effort.

Typically, baseline scenarios are then compared to mitigation scenarios that are constructed to meet different goals for greenhouse gas (GHG) emissions, atmosphereic (sic) concentrations, or temperature change.” Cost-benefit and effectiveness analyses in particular lend themselves to using a fixed baseline against which to evaluate an alternative, creating an incentive for the misuse of scenarios as predictions.

The IPCC warns against treating scenarios as predictions because they reach far into the future – for instance to 2100 and even beyond, and “the idea of business-as-usual in century-long socioeconomic projections is hard to fathom.” Humility in socio-economic prediction is also warranted because our collective track record in anticipating the future, especially when it comes to energy, is really quite poor.

It may seem confusing for the IPCC to recommend the use of baseline scenarios as a reference point for evaluating counterfactual futures and its parallel warning not to use reference scenarios as forecasts. The way for analysts to reconcile these two perspectives is to consider in research a very wide range of counterfactual futures as baselines.

The instant an analyst decides that one particular scenario or a subset of scenarios is more likely than others, and then designates that subset of possible futures as a baseline or “business as usual,” then that analyst has started crossing the bridge to predicting the future. When a single scenario is chosen as a baseline, that bridge has been crossed.

There is of course generally nothing wrong with predicting the future as a basis for decision making. Indeed, a decision is a form of prediction about the future. However, in some contexts we may wish to rely more on decision making that is robust to ignorance and uncertainties (and thus less on forecasts), that might lead to desired outcomes across all scenarios of the future. For instance, if you build a house high on a bluff above a floodplain, you need not worry about flood predictions. In other settings, we may wish to optimize decisions based on a specific forecast of the future, such as evacuation before an advancing storm.

Climate science – and by that I mean broadly research on physical science, impacts, economics as well as policy-related research into adaptation and mitigation —- went off track when large parts of the community and leading assessment bodies like the IPCC decided to anoint a subset of futures (and one in particular) as the baseline against which impacts and policy would be evaluated.

This is best illustrated by a detailed example.

The U.S. National Climate Assessment (NCA) is a periodic report on climate science and policy required in law.  The most recent report was published in two parts in 2017 and 2018. Those reports were centered on anointing a specific scenario of the future as “business as usual” (despite the NCA warning against doing exactly that). That scenario has a technical name, Representative Concentration Pathway (RCP) 8.5.

In his climate epiphany, David Wallace-Wells warned, “anyone, including me, who has built their understanding on what level of warming is likely this century on that RCP8.5 scenario should probably revise that understanding in a less alarmist direction.” The climate science community, broadly conceived, is among those needing to revise their understandings.

To illustrate how the USNCA came to be centered on RCP8.5, let’s take a quick deep dive into how the report was created. It’s use of scenarios was grounded in research done by the U.S. Environmental Protection Agency (EPA) and specifically a project called Climate Change Impacts and Risk Analysis. That project is described in two reports.

The first report, in 2015, explained that its methodology was based on two scenarios, a “business as usual” or “reference” scenario that projected where the world was heading in the absence of climate policies and a “mitigation” scenario representing a future with emissions reductions. In that report EPA created its own scenarios (with its BAU scenario equated to an equivalent RCP8.6 scenario). The report explained that the benefits of mitigation policy were defined by the difference between the BAU scenario and the mitigation scenario.

In its subsequent report in 2017, EPA decided to replace its scenarios with several of the RCP scenarios used by the IPCC. In that report it dropped the phrase “business as usual” and adopted RCP8.5 as its “baseline” scenario fulfilling that role. It adopted another scenario, RCP4.5 as representing a world with mitigation policy. The USNA relied heavily on the results of this research, along with other work using RCP8.5 as a “baseline.”

The USNCA defined the difference in impacts between the two RCP scenarios as representing the benefits to the United States of mitigation policy: “Comparing outcomes under RCP8.5 with those of RCP4.5 (and RCP2.6 in some cases) not only captures a range of uncertainties and plausible futures but also provides information about the potential benefits of mitigation.” But such a comparison was warned against by the creators of the RCP scenarios: “RCP8.5 cannot be used as a no-climate-policy reference scenario for the other RCPs.” Yet, there it was at the center of the most authoritative climate science report in the United States.

Reports are written by committees, and elsewhere the US NCA warned that RCP8.5 “is not intended to serve as an upper limit on possible emissions nor as a BAU or reference scenario for the other three scenarios.” But that warning was not heeded at all. RCP8.5 is used as a reference scenario throughout the report and is mentioned more than 470 times, representing about 56% of all references to RCP scenarios.

It was the USNCA misuse of RCP8.5 that appeared on a page one New York Times story that warned, “A major scientific report issued by 13 federal agencies on Friday presents the starkest warnings to date of the consequences of climate change for the United States, predicting that if significant steps are not taken to rein in global warming, the damage will knock as much as 10 percent off the size of the American economy by century’s end.”

It is not just the USNCA that has centered its work on RCP8.5 as a reference scenario to evaluate climate impacts and policy, the 2019 IPCC report on oceans and ice also adopted RCP8.5 as a reference scenario to compare with RCP2.6 as a mitigation scenario: “Under unmitigated emissions (RCP8.5), coastal societies, especially poorer, rural and small islands societies, will struggle to maintain their livelihoods and settlements during the 21st century.” That report referenced RCP8.5 more than 580 times representing more than 56% of all scenario references in the report.

Across the IPCC 5th assessment report, published in 2013 and 2014, RCP8.5 comprised 34% of scenario references. Dependence on RCP8.5 has increased in the reports of IPCC. And as an indication of where research may be heading, in the abstracts talks given at the 2019 meeting of the American Geophysical Union earlier this month, of those that mentioned RCP scenarios, 58% mentioned RCP 8.5, with RCP4.5 coming in second at 32%. If these abstracts indicate the substance of future scientific publications, then get ready for an avalanche of RCP8.5 studies.

The climate science community, despite often warning itself to the contrary, has gotten off track when it comes to the use of scenarios in impact and policy research. There can be little doubt that major assessments and a significant portion of the underlying literature has slipped into misusing scenarios as predictions of the future.

Why this has happened will no doubt be the subject of future research, but for the immediate future, the most important need will be for the climate science community to hit the reset button and get back on track. Climate change is too important to do otherwise.

Part two will discuss what this reset might look like.

Follow me on Twitter @RogerPielkeJr

Roger Pielke

I have been on the faculty of the University of Colorado since 2001, where I teach and write on a diverse range of policy and governance issues related to science, innovation, sports. I have degrees in mathematics, public policy and political science. My books include The Honest Broker: Making Sense of Science in Policy and Politics published by Cambridge University Press (2007), The Climate Fix: What Scientists and Politicians Won’t Tell you About Global Warming (2010, Basic Books) and The Edge: The War Against Cheating and Corruption in the Cutthroat World of Elite Sports (Roaring Forties Press, 2016). My most recent book is The Rightful Place of Science: Disasters and Climate Change (2nd edition, 2018, Consortium for Science, Policy & Outcomes).

Source: In 2020 Climate Science Needs To Hit The Reset Button, Part One

22.3M subscribers
Stella Wiedemeyer has channelled her mounting frustration surrounding the lack of action from the powers that be in relation to the climate crisis into organising School Strike 4 Climate actions in Melbourne. Through her grassroots engagement, she was selected to join federal political candidates at panel discussions including by Oxfam and is delighted to bring a youthful perspective to an at times demoralising issue. She is working currently to inspire environmental awareness through her personal actions, school community and new found platform within the youth climate justice movement. “I’m looking forward to challenging people to consider their position in our climate and recognise what obligations and privileges we have to create long-lasting, systemic change.” Stella Wiedemeyer is a current year 11 student who has channelled her mounting frustration surrounding the lack of action from the powers that be in relation to the climate crisis into organising School Strike 4 Climate actions in Melbourne. Through her grassroots engagement, she was selected to join federal political candidates at panel discussions including by Oxfam and is delighted to bring a youthful perspective to an at times demoralising issue. She is working currently to inspire environmental awareness through her personal actions, school community and new found platform within the youth climate justice movement. “I’m looking forward to challenging people to consider their position in our climate and recognise what obligations and privileges we have to create long-lasting, systemic change.” This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx

This Is Why We Don’t Shoot Earth’s Garbage Into The Sun

Imagine our planet as it was for the first 4.55 billion years of its existence. Fires, volcanoes, earthquakes, tsunamis, asteroid strikes, hurricanes and many other natural disasters were ubiquitous, as was biological activity throughout our entire measured history. Most of the environmental changes that occurred were gradual and isolated; only in a few instances — often correlated with mass extinctions — were the changes global, immediate, and catastrophic.

But with the arrival of human beings, Earth’s natural environment has another element to contend with: the changes wrought upon it by our species. For tens of thousands of years, the largest wars were merely regional skermishes; the largest problems with waste led only to isolated disease outbreaks. But our numbers and technological capabilities have grown, and with it, a waste management problem. You might think a great solution would be to send our worst garbage into the Sun, but we’ll never make it happen. Here’s why.

The very first launch of the Falcon Heavy, on February 6, 2018, was a tremendous success. The rocket... [+] reached low-Earth-orbit, deployed its payload successfully, and the main boosters returned to Cape Kennedy, where they landed successfully. The promise of a reusable heavy-lift vehicle is now a reality, and could lower launch costs to ~$1000/pound. Still, even with all these advances, we won't be launching our garbage into the Sun anytime soon.

Jim Watson/AFP/Getty Images

Today In: Innovation

At present, there are a little more than 7 billion humans on the planet, and the previous century saw us at last become a spacefaring civilization, where we’ve broken the gravitational bonds that have kept us shackled to Earth. We’ve extracted valuable and rare minerals and elements, synthesized new chemical compounds, developed nuclear technologies, and produced new technologies that far exceed even the wildest dreams of our distant ancestors.

Although these new technologies have transformed our world and improved our quality of life, there are negative side-effects that have come along for the ride. We now have the capacity to cause widespread damage and destruction to our environment in a variety of ways, from deforestation to atmospheric pollution to ocean acidification and more. With time and care, the Earth will begin self-regulating as soon as we stop exacerbating these problems. But other problems just aren’t going to get better on their own on any reasonable timescale.

Nuclear weapon test Mike (yield 10.4 Mt) on Enewetak Atoll. The test was part of the Operation Ivy.... [+] Mike was the first hydrogen bomb ever tested. A release of this much energy corresponds to approximately 500 grams of matter being converted into pure energy: an astonishingly large explosion for such a tiny amount of mass. Nuclear reactions involving fission or fusion (or both, as in the case of Ivy Mike) can produce tremendously dangerous, long-term radioactive waste.

National Nuclear Security Administration / Nevada Site Office

Some of what we’ve produced here on Earth isn’t merely a problem to be reckoned with over the short-term, but poses a danger that will not significantly lessen with time. Our most dangerous, long-term pollutants include nuclear by-products and waste, hazardous chemicals and biohazards, plastics that off-gas and don’t biodegrade, and could wreak havoc on a significant fraction of the living beings on Earth if they got into the environment in the wrong way.

You might think that the “worst of the worst” of these offenders should be packed onto a rocket, launched into space, and sent on a collision course with the Sun, where at last they won’t plague Earth anymore. (Yes, that was similar to the plot of Superman IV.) From a physics point of view, it’s possible to do so.

But should we do it? That’s another story entirely, and it begins with considering how gravitation works on Earth and in our Solar System.

The Mercury-bound MESSENGER spacecraft captured several stunning images of Earth during a gravity... [+] assist swingby of its home planet on Aug. 2, 2005. Several hundred images, taken with the wide-angle camera in MESSENGER's Mercury Dual Imaging System (MDIS), were sequenced into a movie documenting the view from MESSENGER as it departed Earth. Earth rotates roughly once every 24 hours on its axis and moves through space in an elliptical orbit around our Sun.

NASA / Messenger mission

Human beings evolved on Earth, grew to prominence on this world, and developed extraordinary technologies that our corner of the cosmos had never seen before. We all have long dreamed of exploring the Universe beyond our home, but only in the past few decades have we managed to escape the gravitational bonds of Earth. The gravitational pull exerted by our massive planet is only dependent on our distance from Earth’s center, which causes spacetime to curve and causes all objects on or near it — including humans — to constantly accelerate “downwards.”

There’s a certain amount of energy keeping any massive object bound to Earth: gravitational potential energy. However, if we move fast enough (i.e., impart enough kinetic energy) to an object, it can cross two important thresholds.

  1. The threshold of a stable orbital speed to never collide with Earth: about 7.9 km/s (17,700 mph).
  2. The threshold of escaping from Earth’s gravity entirely: 11.2 km/s (25,000 mph).

It takes a speed of 7.9 km/s to achieve "C" (stable orbit), while it takes a speed of 11.2 km/s for... [+] "E" to escape Earth's gravity. Speeds less than "C" will fall back to Earth; speeds between "C" and "E" will remain bound to Earth in a stable orbit.

Brian Brondel under a c.c.a.-s.a.-3.0 license

For comparison, a human at the equator of our planet, where Earth’s rotation is maximized, is moving only at about 0.47 km/s (1,000 mph), leading to the conclusion that we’re in no danger of escaping unless there’s some tremendous intervention that changes the situation.

Luckily, we’ve developed just such an intervention: rocketry. To get a rocket into Earth’s orbit, we require at least the amount of energy it would take to accelerate that rocket to the necessary threshold speed we mentioned earlier. Humanity has been doing this since the 1950s, and once we’ve escaped from Earth, there was so much more to see occurring on larger scales.

Earth isn’t stationary, but orbits the Sun at approximately 30 km/s (67,000 mph), meaning that even if you escape from Earth, you’ll still find yourself not only gravitationally bound to the Sun, but in a stable elliptical orbit around it.

The Dove satellites, launched from the ISS, are designed for Earth imaging and have numbered... [+] approximately 300 in total. There are ~130 Dove satellites, created by Planet, that are still in Earth's orbit, but that number will drop to zero by the 2030s due to orbital decay. If these satellites were boosted to escape from Earth's gravity, they would still orbit the Sun unless they were boosted by much greater amounts.

NASA

This is a key point: you might think that here on Earth, we’re bound by Earth’s gravity and that’s the dominant factor as far as gravitation is concerned. Quite to the contrary, the gravitational pull of the Sun far exceeds the gravitational pull of Earth! The only reason we don’t notice it is because you, me, and the entire planet Earth are in free-fall with respect to the Sun, and so we’re all accelerated by it at the same relative rate.

If we were in space and managed to escape from Earth’s gravity, we’d still find ourselves moving at approximately 30 km/s with respect to the Sun, and at an approximate distance of 150 million km (93 million miles) from our parent star. If we wanted to escape from the Solar System, we’d have to gain about another 12 km/s of speed to reach escape velocity, something that a few of our spacecraft (Pioneer 10 and 11, Voyager 1 and 2, and New Horizons) have already achieved.

The escape speed from the Sun at Earth's distance is 42 km/s, and we already move at 30 km/s just by... [+] orbiting the Sun. Once Voyager 2 flew by Jupiter, which gravitationally 'slingshotted' it, it was destined to leave the Solar System.

Wikimedia Commons user Cmglee

But if we wanted to go in the opposite direction, and launch a spacecraft payload into the Sun, we’d have a big challenge at hand: we’d have to lose enough kinetic energy that a stable elliptical orbit around our Sun would transition to an orbit that came close enough to the Sun to collide with it. There are only two ways to accomplish this:

  1. Bring enough fuel with you so that you can decelerate your payload sufficiently (i.e., have it lose as much of its relative speed with respect to the Sun as possible), and then watch your payload gravitationally free-fall into the Sun.
  2. Configure enough fly-bys with the innermost planets of our Solar System — Earth, Venus and/or Mercury — so that the orbiting payload gets de-boosted (as opposed to the positive boosts that spacecraft like Pioneer, Voyager, and New Horizons received from gravitationally interacting with the outer planets) and eventually comes close enough to the Sun that it gets devoured.

The idea of a gravitational slingshot, or gravity assist, is to have a spacecraft approach a planet... [+] orbiting the Sun that it is not bound to. Depending on the orientation of the spacecraft's relative trajectory, it will either receive a speed boost or a de-boost with respect to the Sun, compensated for by the energy lost or gained (respectively) by the planet orbiting the Sun.

Wikimedia Commons user Zeimusu

The first option, in reality, requires so much fuel that it’s practically impossible with current (chemical rocket) technology. If you loaded up a rocket with a massive payload, like you might expect for all the hazardous waste you want to fire into the Sun, you’d have to load it up with a lot of rocket fuel, in orbit, to decelerate it sufficiently so that it’d fall into the Sun. To launch both that payload and the additional fuel requires a rocket that’s larger, more powerful and more massive than any we’ve ever built on Earth by a large margin.

Instead, we can use the gravity assist technique to either add or remove kinetic energy from a payload. If you approach a large mass (like a planet) from behind, fly in front of it, and get gravitationally slingshotted behind the planet, the spacecraft loses energy while the planet gains energy. If you go the opposite way, though, approaching the planet from ahead, flying behind it and getting gravitationally slingshotted back in front again, your spacecraft gains energy while removing it from the orbiting planet.

The Messenger mission took seven years and a total of six gravity assists and five deep-space... [+] maneuvers to reach its final destination: in orbit around the planet Mercury. The Parker Solar Probe will need to do even more to reach its final destination: the corona of the Sun. When it comes to reaching for the inner Solar System, spacecraft are required to lose a lot of energy to make it possible: a difficult task.

NASA/JPL

Two decades ago, we successfully used this gravitational slingshot method to successfully send an orbiter to rendezvous and continuously image the planet Mercury: the Messenger mission. It enabled us to construct the first all-planet mosaic of our Solar System’s innermost world. More recently, we’ve used the same technique to launch the Parker Solar Probe into a highly elliptical orbit that will take it to within just a few solar radii of the Sun.

A carefully calculated set of future trajectories is all that’s required to reach the Sun, so long as you orient your payload with the correct initial velocity. It’s difficult to do, but not impossible, and the Parker Solar Probe is perhaps the poster child for how we would, from Earth, successfully launch a rocket payload into the Sun.

Keeping all this in mind, then, you might conclude that it’s technologically feasible to launch our garbage — including hazardous waste like poisonous chemicals, biohazards, and even radioactive waste — but it’s something we’ll almost certainly never do.

Why not? There are currently three barriers to the idea:

  1. The possibility of a launch failure. If your payload is radioactive or hazardous and you have an explosion on launch or during a fly-by with Earth, all of that waste will be uncontrollably distributed across Earth.
  2. Energetically, it costs less to shoot your payload out of the Solar System (from a positive gravity assist with planets like Jupiter) than it does to shoot your payload into the Sun.
  3. And finally, even if we chose to do it, the cost to send our garbage into the Sun is prohibitively expensive at present.

This time-series photograph of the uncrewed Antares rocket launch in 2014 shows a catastrophic... [+] explosion-on-launch, which is an unavoidable possibility for any and all rockets. Even if we could achieve a much improved success rate, the risk of contaminating our planet with hazardous waste is prohibitive for launching our garbage into the Sun (or out of the Solar System) at present.

NASA/Joel Kowsky

The most successful and reliable space launch system of all time is the Soyuz rocket, which has a 97% success rate after more than 1,000 launches. Yet a 2% or 3% failure rate, when you apply that to a rocket loaded up with all the dangerous waste you want launched off of your planet, leads to the catastrophic possibility of having that waste spread into the oceans, atmosphere, into populated areas, drinking water, etc. This scenario doesn’t end well for humanity; the risk is too high.

Considering that the United States alone is storing about 60,000 tons of high-level nuclear waste, it would take approximately 8,600 Soyuz rockets to remove this waste from the Earth. Even if we could reduce the launch failure rate to an unprecedented 0.1%, it would cost approximately a trillion dollars and, with an estimated 9 launch failures to look forward to, would lead to over 60,000 pounds of hazardous waste being randomly redistributed across the Earth.

Unless we’re willing to pay an unprecedented cost and accept the near-certainty of catastrophic environmental pollution, we have to leave the idea of shooting our garbage into the Sun to the realm of science fiction and future hopeful technologies like space elevators. It’s undeniable that we’ve made quite the mess on planet Earth. Now, it’s up to us to figure out our own way out of it.

Follow me on Twitter. Check out my website or some of my other work here.

Ethan Siegel Ethan Siegel

I am a Ph.D. astrophysicist, author, and science communicator, who professes physics and astronomy at various colleges. I have won numerous awards for science writing since 2008 for my blog, Starts With A Bang, including the award for best science blog by the Institute of Physics. My two books, Treknology: The Science of Star Trek from Tricorders to Warp Drive, Beyond the Galaxy: How humanity looked beyond our Milky Way and discovered the entire Universe, are available for purchase at Amazon. Follow me on Twitter @startswithabang.

Source: This Is Why We Don’t Shoot Earth’s Garbage Into The Sun

BRIGHT SIDE
30.2M subscribers
How to Stop Water Polution. In case you’re wondering what water polution has to do with a new continent discoevered in the Pacific Ocean, here’s the answer to this mystery. This new continent is an island that consists solely of garbage and plastic waste. Some countries are ready to announce an ecological disaster. Let’s see if there’s something we can all do to save the planet. TIMESTAMPS The popularity of plastic 0:26 Garbage islands 1:47 The Great Pacific Garbage Patch 2:30 Problems connected with the plastic pollution of the ocean 4:39 Bali ecological disaster 7:31 Several ways to solve problem 8:26 #newcontinent #garbageisland #ecologicalproblem Music: Butchers – Silent Partner https://www.youtube.com/audiolibrary/… SUMMARY -2 million plastic bags a minute are thrown away. As for bubble wrap, the amount produced in just one year would be enough to cover our planet around the equator. 500 billion plastic cups are used and disposed of annually. -There are 3 huge garbage islands in the world: in the central North Pacific Ocean, in the Indian Ocean, and in the Atlantic Ocean. -The size of the Great Pacific Garbage Patch is currently more than 600,000 square miles. According to the journal Scientific Reports, there are more than 1.8 trillion pieces of plastic that have accumulated in this area. -Plastic objects in the ocean kill animals or get stuck in their bodies. Some types of plastic are toxic. In addition, plastic has the ability to absorb such poisonous substances as mercury. Birds often choke to death after trying to swallow a bright object that has caught their eye. -Indonesian authorities have recently declared a “garbage emergency.” More than 100 tons of waste brought ashore every day to beaches from Seminyak and Jimbaran to Kuta. -To solve the problem, people can find a way to remove the garbage that is already in the ocean. Another way out is to decrease pollution or stop it completely. Subscribe to Bright Side : https://goo.gl/rQTJZz —————————————————————————————- Our Social Media: Facebook: https://www.facebook.com/brightside/ Instagram: https://www.instagram.com/brightgram/ 5-Minute Crafts Youtube: https://www.goo.gl/8JVmuC —————————————————————————————- For more videos and articles visit: http://www.brightside.me/

Category

Howto & Style

 

Share this:

Like this:

Like Loading...

Why The Track Forecast For Hurricane Dorian Has Been So Challenging

Here is something that you can take to the bank. We will not see the name “Dorian” used in the Atlantic basin for any future hurricane. The names of particularly destructive or impactful storms are retired. According to the National Hurricane Center, Dorian is now tied with the 1935 Labor Day hurricane for the strongest Atlantic hurricane landfall on record. In a 3 pm advisory on September 1st, the National Hurricane Center warned of gusts to 220 mph and 18 to 23 feet storm surges for parts of the Abacos.

I have been in the field of meteorology over 25 years and do not recall seeing warnings about 220 mph gusts for a hurricane. Hurricane watches have also been issued for Andros Island and from North of Deerfield Beach to the Volusia/Brevard County Line in Florida. At the time of writing, the official forecast from the National Hurricane Center is for a northward curve and no direct Florida landfall. This is dramatically different from forecasts only a few days ago.

There is still uncertainty with the forecast so coastal Florida, Georgia, and the Carolinas should remain on high alert. Why has the track forecast been so challenging with Hurricane Dorian?

Historically, hurricane track forecasts have outpaced intensity forecasts. I discuss the reasons why in a previous Forbes article at this link. With Hurricane Dorian, uncertainty about the forecast track and timing of the storm forced officials to move the Florida State – Boise State football game from Jacksonville, slated for a 7 pm kickoff on Saturday, to noon in Tallahassee. I am certain that many businesses and people are questioning the move given that timing of when impacts are now expected. Unfortunately, officials and emergency managers often must make decision on the best information at the moment.

Some people may be tempted to use uncertainty with this forecast to spew vitriol or skepticism at meteorologists and our models. However, challenges with Hurricane Dorian’s track forecast do not define the legacy of weather forecasts. It would be silly to say that the NFL’s best field goal kicker is terrible based on a few misses.

So what’s going on? I asked a panel of tropical meteorology experts.

Today In: Innovation

Speed of motion of Hurricane Dorian has been a significant challenge. Professor John Knox, a recent recipient of the American Meteorological Society’s Edward Lorenz Teaching Award, offers an important lesson. The University of Georgia atmospheric sciences professor pointed out:

Before you bash the meteorologists for being stupid: one reason the forecasted track has changed is because the forecasts of the forward speed of Dorian have slowed it down more and more. If it had chugged along as originally forecast, it likely would have hit east-central Florida and then maybe gone into the Gulf, before the high pressure above us in the Southeast would break down. But, because it’s moving more slowly, the high-pressure break down is opening the gate, so to speak, for Dorian to go more northward and eastward. So, the change in forecast is tied tightly to the arrival timing.

Professor John Knox, University of Georgia

Dr. Phillippe Papin is an Atmospheric Scientist and Associate Postdoctoctor Scientist at the U.S. Naval Research Laboratory. Papin also points to the high pressure as being a factor. He wrote:

the ridge to the north of Dorian has been steering Dorian off to the west the last few days….But there is a weak trough that is swinging into the eastern US that is going to erode the strength to the ridge enough so that a gap forms to the north of Dorian and it begins to move further to the north.

Dr. Phillippe Papin, U.S. Naval Research Laboratory

The timing of when that weakness develops and on how far Dorian makes it west in the meantime has been the source of uncertainty in the model guidance for the last 2-3 days according to Papin. At the time of writing, there is still some spread in the model solutions.

Dr. Michael Ventrice is a tropical weather expert with IBM and The Weather Company. He has been concerned about the storm environment and how well the models are capturing the rapidly evolving situation. He told me:

I believe the uncertainty is derived from how the models are resolving Dorian, locally. The recent intensification of the storm today is not being resolved by the models properly at the time of the 12z initialization. The interaction with the Bahamas, how that interaction might alter the mesoscale structure of the Hurricane, if that interaction induces a wobble, are all valid questions at this point in time

Michael Ventrice — IBM/The Weather Company

A hurricane of this size and intensity can certainly modify its environment and be modified by that environment. Sam Lillo, a doctoral candidate at the University of Oklahoma, tweeted an interesting point on the afternoon of September 1st about how worrisome the rapid intensification and track uncertainty of Hurricane Dorian has been:

The track uncertainty in NWP at under 3-day lead-time is very uncomfortable, especially considering proximity to land. This would be uncomfortable for any hurricane. But then make it a category 5.

Sam Lillo, doctoral candidate in meteorology at the University of Oklahoma

Our best models have oscillated (and in some cases continue to do so) within the past 24-36 hours on just how close Dorian will get to Florida before curving northward. Lillo offers some further insight into what Dr. Ventrice was alluding to about the environment:

As Dorian strengthened faster than expected, diabatic outflow developed an upper level anticyclone to the southwest, adding southerly and westerly components to the steering flow. The westerly component in particular slowed the forward motion of the hurricane, and now its track across the Bahamas coincides with a trough that sweeps across the Mid Atlantic and Northeast on Monday. This trough cuts into the ridge to the north of Dorian, with multiple steering currents now trying to tug the hurricane in all different directions. The future track is highly sensitive to each of these currents, with large feedback on every mile the hurricane jogs to the left or right over the next 24 to 48 hours.

Sam Lillo, doctoral candidate in meteorology at the University of Oklahoma

Lillo offers a nice meteorological explanation. In a nutshell, he is saying that the rapid intensification perturbed the near-storm environment and now there may be other steering influences besides the ridge of high pressure that the models are struggling to resolve.

In a previous Forbes piece last week, I mentioned that forecasts in the 5+ day window and beyond can have errors of 200 miles and that the information should be used as “guidance” not “Gospel.” Because there is still uncertainty with the models and Dorian is such a strong storm, residents from coastal Florida to the Carolinas must pay attention and be prepared to act. I have complete confidence in my colleagues at the National Hurricane Center, and they should always be your definitive source with storms like this. They still maintain an eventual curve northward before the storm reaches the Florida coast. However, the issuance of hurricane watches in Florida also indicates that they know the margin of error is razor thin.

Follow me on Twitter. Check out my website.

Marshall Shepherd

Dr. J. Marshall Shepherd, a leading international expert in weather and climate, was the 2013 President of American Meteorological Society (AMS) and is Director of the University of Georgia’s (UGA) Atmospheric Sciences Program. Dr. Shepherd is the Georgia Athletic Association Distinguished Professor and hosts The Weather Channel’s Weather Geeks Podcast, which can be found at all podcast outlets. Prior to UGA, Dr. Shepherd spent 12 years as a Research Meteorologist at NASA-Goddard Space Flight Center and was Deputy Project Scientist for the Global Precipitation Measurement (GPM) mission. In 2004, he was honored at the White House with a prestigious PECASE award. He also has received major honors from the American Meteorological Society, American Association of Geographers, and the Captain Planet Foundation. Shepherd is frequently sought as an expert on weather and climate by major media outlets, the White House, and Congress. He has over 80 peer-reviewed scholarly publications and numerous editorials. Dr. Shepherd received his B.S., M.S. and PhD in physical meteorology from Florida State University.

Source: Why The Track Forecast For Hurricane Dorian Has Been So Challenging

National Hurricane Center director Ken Graham provides an update on Hurricane Dorian. RELATED: https://bit.ly/2NFZCak Dorian’s slow crawl, estimated at about 7 mph on Sunday afternoon, placed it within 185 miles of West Palm Beach, Florida. But forecasters remained unsure of whether, or where, it might make landfall in the U.S. after it makes an expected turn to the north.

That left millions of people from South Florida to North Carolina on alert and preparing for the worst. » Subscribe to USA TODAY: http://bit.ly/1xa3XAh » Watch more on this and other topics from USA TODAY: https://bit.ly/2JYptss » USA TODAY delivers current local and national news, sports, entertainment, finance, technology, and more through award-winning journalism, photos, videos and VR. #hurricanedorian #dorian #hurricanes

%d bloggers like this: