Space View

Why the 2017 solar eclipse is generating so much excitement in the US

The eclipse will be one of the most digitally recorded events ever.

If you’ve never seen a solar eclipse before, you should make an effort to witness the breathtaking event on August 21. While only people in the US will be able to see the total eclipse – in which the moon completely blocks the light from the sun – those living in parts of South America, Africa and Europe should be able to see at least a partial solar eclipse.

Solar eclipses occur when the moon passes between the Earth and the sun so that it blocks part or all of the sunlight as viewed from a particular location on our planet. Earth is the only planet in the solar system where this can happen in this way. This is because of the moon’s size and its relative distance from the sun – when viewed from the Earth, it can identically cover the bright solar disc to reveal the tenuous, wispy outer atmosphere of the star (called the solar corona).

An eclipse does not happen every time the moon travels around the Earth. This is because its orbit has a slight inclination (about five degrees) relative to our planet’s journey around the sun. However when aligned correctly, the result is an awesome, emotional experience. Once the eclipse has begun, the moon continues to eat its way across the blazing sun before darkness falls, the temperature drops and the sky is dominated by a radiant crown around the moon. It happens approximately every 18 months.

During an eclipse the sun’s corona becomes visible to observers on Earth.  NASA
During an eclipse the sun’s corona becomes visible to observers on Earth. NASA

On August 21, the moon’s shadow will travel West to East, touching land at Lincoln Beach, Oregon at 09:05 Pacific Daylight Time before speeding across North America at up to 1 km per second and finally exiting close to Charleston, South Carolina, at 16:09 Eastern Daylight Time. The longest total eclipse will occur close to the town of Carbondale, Illinois – lasting about two minutes and 40 seconds.

Anywhere within the 110 km wide path of the eclipse, observers will be able to see the sun completely covered. Outside of that, sky-watchers will still see a partial eclipse with decreasing percentages of the sun’s surface covered as one moves away from this narrow corridor. It is estimated that over 12 million Americans live in the path of the total eclipse itself and another 200 million people within a day’s drive of it. This is science engagement on an unprecedented scale and is likely to be the most orchestrated eclipse viewing event ever undertaken.

Digital deluge

Social media activity has been increasing for months now, building up the anticipation to be part of this rare event. Expect Twitter, Facebook, Snapchat, Flickr and Instagram to be swamped with eclipse pictures during and after the event. In fact, the eclipse should be one of the most digitally recorded events ever, which could be of use to scientists. The Citizen CATE (Continental-America Telescopic Eclipse) experiment aims to capture images of the inner solar corona using a network of more than 60 telescopes operated by citizen scientists, high school groups and universities.

Similarly, the Eclipse Mega-movie is asking observers to use their app to upload eclipse images along the path of totality to produce an expanded and continuous film of the total eclipse as it crosses the country. Both of these experiments will produce unique data-sets of the white light corona, a region that is usually impossible to observe because the exceptionally bright solar disc hides it from view. We will be able to examine like never before the detailed structure of the solar corona and how it is dragged out into space by the solar wind.

There is also a big focus on education. A top priority is making sure that people know how to safely view the eclipse. Looking directly at the sun is unsafe except during that brief period of the total eclipse. It is vitally important that only special solar filters, such as certified eclipse glasses, are used. Unfiltered cameras, telescopes, binoculars or other optical devices concentrate the solar rays and are a definite no-go in regard to eye safety. If no filters are available, it is best to use a pinhole camera to project the eclipse indirectly.

It is also important to take advantage of the amazing opportunity to inform a huge population about the science behind the event. There are thousands of astronomy-oriented events, parties even, being hosted along the path of totality.

New science?

Scientists are equally excited. Eleven NASA and NOAA satellites, high-altitude balloons, hundreds of ground-based telescopes and even the International Space Station will all take advantage of this unique shadow-chase across the surface of the Earth. However, it is not just looking up at the moon and sun that is important. Total eclipses also provide us with an unprecedented opportunity to examine our own planet under quite unusual conditions.

NASA says that observers across several states will measure the radiant energy from the sun into the Earth’s atmosphere from the ground as well as from space. This should provide new insights into how the incident solar energy in our atmosphere changes when particles, clouds and in this case the moon, prevents sunlight from reaching the surface of the planet.

Play

I will be fortunate enough to be part of a four-hour live online telecast of the eclipse from Carbondale via NASA’s video podcast EDGE. This will include interviews with scientists and live panel questions, high-resolution sun images and a balloon launch. As a solar physicist who can only usually observe the solar corona from space by satellite instrumentation, it is special to be able to glimpse the corona with the (protected) naked eye for a brief time.

One interesting part to all this is the fact that the US gets another chance in seven years to maximise the opportunities that the eclipse brings.

It is said that one of the longlasting legacies of the Apollo missions to the moon is the number of American scientists today who were inspired to be engineers and scientists. Though this solar eclipse is science engagement in a different manner, the end goal is the same – bringing about not just a greater appreciation of the Earth, and solar or lunar research, but also sparking a desire in many young people to be the science leaders of the future.

Robert William Walsh, Professor of Solar Physics, University of Central Lancashire.

This article first appeared on The Conversation.

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Uninterrupted power supply during natural disasters can be a reality

The right material can protect electricity poles from getting damaged even during natural disasters.

According to a UN report, natural disasters in the last decade have occurred almost twice as often compared to two decades ago, with Asia being the hardest hit. The report reveals that the number of such events had gone up 14% annually between 2005 and 2015 compared to the period 1995-2014. Such findings have driven countries like UK and USA to accelerate their resilience building measures. ‘Resilience’ implies preparedness and having a robust coping mechanism to deal with the damage wrought by hurricanes, earthquakes, floods and other violent natural events. The United Nations Office for Disaster Risk Reduction (UNISDR) has even launched a campaign called Making Cities Resilient which suggests, among other things, increasing the resilience of infrastructure for crucial services including electrical power, transport, healthcare and telecommunications.

India’s vulnerability to natural disasters

The UN report lists India as third among the countries hit by the highest number of weather related disasters in the past decade. The Centre for Research on the Epidemiology of Disasters in its Annual Disaster Review for 2014 also listed India among the five countries most frequently hit by natural disasters.

According to the National Cyclone Risk Mitigation Project, almost 5,700 kilometers of India’s 7,500 kilometers of coastline are highly vulnerable to the impact of tropical cyclones and related meteorological hazards. Research by Verisk Maplecroft also shows that 82% of the population in India are exposed to natural hazards, compared with 50% of the population in China.

What is also disturbing is the increased vulnerability of populous Indian cities to the effects of these natural disasters, caused by growing population density, haphazard construction activities and inadequate preparedness. The recent Mumbai floods which crippled the city in August 2017, for example, were exacerbated by the city’s out-of-date drainage system and unbridled construction over the city’s natural nullahs, which otherwise could have effectively drained excess water. A report on World Disasters by the International Federation of Red Cross and Red Crescent Societies (IFRC), lists Mumbai among the 10 most vulnerable cities in terms of floods and earthquakes. A survey shows that, on an average, 21 Indian cities scored between 2.5 to 4 points out of 10 on governance parameters that measure preparedness for disasters.

Regions like the North East in India are particularly susceptible to natural disturbances like earthquakes, floods and landslides. According to the National Flood Commission, Assam, for example, accounts for 9.4% of the total flood prone area in the country. The commission estimated that due to floods, Assam suffered a loss of Rs, 3,100 crores in the past five decades. The whole of Brahmaputra Valley in Assam is in fact considered one of the most hazard prone regions in the country, with more than 40% of its land (3.2 million hectares) being susceptible to flood damage.

All these point to the need for resilience building measures, particularly to protect crucial infrastructure like electrical power – one of the first casualties during a natural disaster. For example, when Hurricane Sandy struck the US East Coast in 2012, about 2,427 utility poles were toppled or broken, reportedly shutting off power to more than 8.5 million households. Back home, when Cyclone Wardah hit Chennai in December 2015, power supply was disrupted in the city and its neighbouring districts of Kancheepuram and Tiruvallur. Reports said thousands of concrete poles just collapsed and reportedly 32,000 poles had to be replaced in the three districts. Government officials were even quoted as saying that the estimated loss from uprooted poles alone was about Rs 65 crore. Inability of electricity poles (also called utility poles) to withstand strong winds contributes significantly to the disruption of power supply during such natural occurrences.

So how can critical infrastructure like electricity poles be saved during a disaster like a cyclone? One way could be to use better-suited material.

Ensuring power supply during natural contingencies

When typhoon Rammasun hit Guangdong in China, more than 70,000 concrete and metal poles collapsed. Earlier, in the aftermath of the massive Chuetsu earthquake in Japan in 2004, about 3,400 utility poles supporting communication cables were broken or toppled.

A post-event assessment revealed that many of the damaged poles were concrete. Concrete poles are comparatively difficult to repair or replace because of their weight and dependence on heavy machinery to install them. Besides, concrete has low tensile strength and often requires the use of materials like steel for reinforcement. When moisture seeps in through cracks in the concrete, the steel reinforcement rusts leading to further deterioration of the concrete pole.

There have been other instances of concrete and metal poles being completely destroyed by natural forces. In tornadoes that ripped through Florida in the late 90s for example, even 100-foot spun concrete transmission poles tested to withstand 250 mph winds, toppled. Ice storms such as the 1998 North American Ice Storm caused over a 1,000 steel towers to collapse under the accumulated weight of the ice. Some of these incidents led to the continued use of wood as a preferred material for utility poles. But environmental concerns emerged due to the use of certain chemicals for treatment of the wooden poles. Additionally, wooden poles are also vulnerable to natural disasters - in the earlier mentioned ice storm, over 30,000 wooden poles were found to have collapsed in addition to the steel ones. In the last few years, research has been conducted into the use of various other materials for utility poles even as wood, steel and concrete remained popular choices. But while all of them have their advantages, they also come with distinct disadvantages.

Concrete, for example, is strong, fire resistant and termite/rot proof, but has as previously mentioned, other disadvantages. Galvanized steel offers similar advantages as concrete, while also being lighter. However, it is also expensive, energy intensive to make, and hazardous since it conducts electricity. Wood, traditionally a popular material for utility poles, is also prone to decay and termite attacks, besides having low resistance to fire when unprotected.

All these factors have led to the development of new materials such as fibre reinforced polymer (FRP), which have proved to offer durability even during high intensity typhoons. For example, in the Rammasun typhoon mentioned earlier, a group of FRP utility poles were found to stand firm even when exposed to strong winds. These poles are made of a special kind of high-strength, high-flexibility polyurethane (PU) composite material called ‘Elastolit®’ developed by BASF. The poles have a strength that is easily 10 times greater than their weight and are only 250 kg, making them easy to transport and install them virtually anywhere. They are more durable and resilient than concrete poles, can withstand severe weather conditions and can also be optimized for specific conditions.

As in the case of Guangdong in China, replacing concrete poles with these FRP poles in areas facing high exposure to natural disasters in India has the potential to reduce the disruption caused to power supply during such events. To know more about BASF’s initiatives in this regard, click here.

This article was produced by the Scroll marketing team on behalf of BASF and not by the Scroll editorial team.