Swords Into Plowshares – the 25th year
By Prof. Shimon Silman, RYAL Institute and Touro College
In part 1 of this series, we reviewed the history of satellites, which were invented for military purposes, and discussed many ways in which they are now used for peaceful purposes. We continue our discussion with examples of how satellites are used to save lives from natural disasters and deadly diseases.
LANDSAT FOR LANDSLIDES
Images from weather satellites can warn people of an impending disaster such as a hurricane, a flood, a fire or a volcano. Then higher resolution satellites like Landsat can help locate, and aid in the rescue of, the victims of a disaster. It can assess the extent of the damage afterwards and warn of possible follow up risks like landslides. For example, Landsat sensors enable scientists to see the heat from wildfires both during and after the fire, and the lava flows from volcanic eruptions, even when gases from the volcanoes obscure the view from human eyes.
Nepal is a small, mountainous country in Southeast Asia where many Israelis vacation. In April, 2015, the Gorkha earthquake in Nepal killed nearly 9,000 people, injured nearly 22,000 and left hundreds of thousands homeless. It was the worst natural disaster in Nepal in 80 years.
Immediately, an international team of volunteer scientists from eight different countries—from the U.S. to the U.K. to Japan and China—assembled to go through satellite imagery of the region to identify earthquake-induced landslides. According to Dalia Kirschbaum, a remote sensing scientist at NASA’s Goddard Space Flight Center and a leader of a landslide mapping effort, “Landslides are a common secondary hazard triggered by earthquakes or rainfall. Because landslides can mobilize and move so quickly, they often cause more damage than people realize.” Many more lives were at stake.
In the first month after the earthquake, the team mapped nearly 1,000 landslides that occurred and created vulnerability maps to show where more landslides were likely to occur. This information helped guide relief efforts to affected areas and alert people in other areas to the danger.
Mapping landslides was especially important because of the impending monsoon season. The highest number of landslides occurs during the rainy months, between June and October. In general, if the land has slid in a specific area, it will have a higher likelihood of experiencing another landslide because the ground is unstable and more susceptible to environmental triggers like heavy rain. As a result of the earthquakes, they were expecting more landslides than usual.
In addition to Landsat, data from the ASTER instrument on the Terra satellite and Earth Observing-1 satellite were used, as well as images and topographic information accessible in Google Earth.
An independent, Canadian-based group has been locating landslides and potential landslides by analyzing areas before and after earthquakes using data from RADARSAT-2, an Earth-observing satellite from Canadian Space Agency.
STOPPING THE SPREAD OF DISEASE
Landsat, SPOT and similar satellites are now being used to track the spread of diseases, especially those whose spread is unpredictable such as vector-borne diseases. A vector is a living organism that can transmit infectious diseases between humans, or from animals to humans. Various animal and insect species from mice to mosquitoes serve as vectors that can transmit disease pathogens to people. Many of these vectors are bloodsucking insects, which ingest disease producing microorganisms during a blood meal from an infected host (human or animal) and later inject them into a new host during a subsequent blood meal. Mosquitoes are the best known disease vector. Others include ticks, flies and fleas.
Every year there are more than 1 billion cases and over 1 million deaths globally from vector-borne diseases such as malaria, dengue, yellow fever, West Nile disease, Lyme disease and Zika. More than 2.5 billion people in over 100 countries are at risk of contracting dengue alone. According to the World Health Organization, Malaria is among the most deadly, preventable vector-borne diseases. About half of the world’s population (3.3 billion people) is at risk of contracting malaria from mosquitoes and it causes more than 400,000 deaths globally every year, most of them children under the age of 5.
As reported in the medical journal Emerging Infectious Diseases, “Perhaps the broadest use of Landsat and SPOT data has been to identify and map vegetation or crop types. This factor is important because the distribution of vegetation types integrates the combined impact of rainfall, temperature, humidity, topographic effects, soil, water availability, and human activities. Nearly all vector-borne diseases are linked to the vegetated environment during some aspect of their transmission cycle; in many cases, this vegetation can be sensed remotely from space.”
Landsat measurements can also pinpoint environmental health risks. With a spatial resolution of 30 meters, it is well suited to mapping various components of changing landscapes, including the distribution of vegetation types mentioned above. Landsat measures reflected light in both visible wavelengths and infrared wavelengths. This combination of measurements helps scientists gauge how healthy the vegetation is, since growing plants generally absorb red light and reflect infrared light. Knowing the health of plants informs decision makers about cropland productivity and habitat conditions for disease-carrying insects and animals.
Its level of detail can also show where water has accumulated in depressions to become breeding grounds for disease-carrying insect vectors. This information allows health officials to take preventative measures such as spraying pesticide to control larval populations. Scientists combine the 30-meter Landsat data with less detailed daily satellite data of weather and vegetation to identify conditions conducive to disease outbreaks before an outbreak occurs.
MORE EXAMPLES…
In Brazil, a certain vector borne disease was spreading in urban areas. The disease was known to be transmitted by infected flies, but scientists did not know why it would hit certain areas of the cities whereas other areas were not affected. Landsat was used to identify how the flies were spreading the disease. It appeared that forest animals such as foxes were emerging from the forest, carrying the flies infected with the disease, and entering certain areas of the city which border on the forest, thereby spreading the disease to the city. The disease could then be stopped at the point that it enters the city before it spreads.
Closer to home, Landsat has achieved the same kind of success right here in New York State with respect to Lyme Disease, which is spread by ticks carried by forest animals. Usually deer carry the ticks, and if a person is bitten by the tick, he may contract the disease. Landsat has identified certain areas in Westchester County, for example, which are particularly conducive to the spread of this disease because of their proximity to the forest (so that forest animals coming out of the forest make contact with people nearby), as well as the abundance of shade and moisture in those areas which also contributes to the spread of the disease.
Another deadly disease whose spread has been elusive is cholera. Certain parts of the world are especially prone to outbreaks of cholera, such as India and other countries in that region. But it has been observed that since the early 1800s there have been seven worldwide epidemics of cholera, leaving scientists mystified: how did the disease spread throughout the world?
Landsat has been used to identify oceanic conditions contributing to the reproduction of the bacteria that cause cholera. It was found that the bacteria itself actually grow in the oceans, and can therefore be transmitted by ocean currents. The growth and spread of the cholera bacteria is a result of the warming of the ocean in certain areas, the sea level, and certain green plants in the ocean on which these bacteria feed. Landsat has been used to identify those locations in the ocean which are conducive to the spread of the bacteria and then to forewarn those countries to which it is likely that the epidemic would spread.
THE DREADED ZIKA VIRUS
Until recently, hardly anyone ever heard of the Zika virus. Then suddenly, in early 2016, the Centers for Disease Control (CDC) and the World Health Organization (WHO) announced that it was “spreading explosively” and began issuing warnings. Where did this virus come from?
The story starts in 1947, in Uganda, near the west shore of Lake Victoria known as Zika Forest, where scientists were studying yellow fever. While examining a monkey thought to be carrying the yellow fever virus, they found a new virus that no one had ever seen before. They called it Zika. Later, the same virus was also found in the Aedes mosquitoes, now known to be a vector of the Zika virus, transmitting it from host to host when they bite.
Eventually it was found infecting people too, and not just in Africa but also in Asia, and in 2007 more than 100 became infected on an island in the southwestern Pacific, but the symptoms—headache, fever, a rash, bloodshot eyes—were generally mild and no one needed to be hospitalized.
Then, in 2013, Zika emerged more dramatically in French Polynesia, and about 28,000 people (11% of the population) needed medical care. 72 patients suffered severe neurological symptoms, 40 of whom contracted Guillain-Barré syndrome, a dangerous autoimmune dysfunction. That was the first indication that the Zika virus could be dangerous.
In 2015, the virus showed up in northeastern Brazil and a few months later there was a drastic increase in the number of cases of babies born with microcephaly in the same area. Microcephaly is a birth defect in which the brain has been damaged or shrunk, resulting in an abnormally small head. Amniotic fluid taken from a few of the mothers of those babies showed that the Zika virus was present, suggesting that there was a link between the Zika virus and microcephaly. Further research has confirmed that Zika causes microcephaly. It was found later that babies born looking normal and healthy after a Zika infection were developing smaller-than-normal heads months later, showing that the virus continues to damage a baby for weeks or months.
As the number of cases rose, fear and anxiety grew. It had already spread to Central America and the Caribbean. Was it coming to the United States? The CDC and the WHO began to issue warnings—especially for women who were pregnant or expecting to become pregnant.
It did reach the U.S. and, at the time of this writing, it is still a threat in some parts of the country. Here’s where the satellites come in.
NASA is assisting public health officials, scientists and communities to try to limit the spread of the Zika virus in the U.S. Scientists at the agency’s Marshall Space Flight Center in Huntsville, Alabama, have joined up with the National Center for Atmospheric Research in Boulder, Colorado, and other institutions to forecast the potential spread of the virus. To determine the potential risk in the mainland United States, in early 2016 the scientists applied methodology being employed in their current vector-borne disease project to potentially identify and predict the spread of Zika in 50 cities across the U.S. in or near the known range of the Aedes aegypti mosquito, which is spreading the virus. (The team has studied this mosquito species for years, because it also transmits the dengue and chikungunya viruses.)
The research team looked at key factors—including temperature and rainfall — that contribute to the spread of Zika virus, to understand where and when a potential outbreak may occur. Their final product, a Zika risk map, help government agencies and health organizations better prepare for possible disease outbreaks related to the spread of the virus.
They found that the Aedes aegypti mosquito would increase in number across much of the southern and eastern U.S. as the weather warms across those regions in the summer months. Summertime weather conditions are favorable for populations of the mosquito along the East Coast as far north as New York City and across the southern tier of the country as far west as Phoenix and Los Angeles.
“Knowledge is one of the most effective barriers to disease transmission and can alleviate unnecessary concern,” commented one NASA scientist. “By identifying the key risk factors and producing forecasts of disease transmission, we can enable citizens to take effective actions that will greatly reduce their risk of disease.”
A SATELLITE STORY
It was a dark night in New Jersey. We were driving to Morristown for the Bar Mitzva of my nephew. My son had rented a minivan and he was driving. But we didn’t know how to go. That was OK though because we had a GPS. So we all sat back and relaxed and listened to the GPS. Wherever it told us to go we went and we got out of New York City successfully.
But now we were on a long, dark, lonely highway in New Jersey. We didn’t know where we were. Was this the right highway? When do we get off? The GPS said nothing. As we kept on driving in silence, I watched the look of uncertainty on my son’s face and an uneasy feeling started to come over me which eventually crystallized into two words: “We’re lost.” We had apparently lost contact with the GPS and we didn’t know where the highway was taking us. How long would it be before we decided that we have to turn around and try to find our way home? Forget about the Bar Mitzva.
Suddenly, a calm voice came over the GPS, “In 500 feet take the exit on the right.” We were OK, we were on track and not lost. The GPS had not forgotten about us. What joy, what a relief!
We exited the highway as we were instructed, but then came a lot more turns on more dark roads and we missed some of them. I was afraid that an angry voice would come over the GPS and say something like, “I told you to turn left at the last intersection and you didn’t listen to me! Now you’re on your own.” But instead, the same calm voice came on and said only one word: “Recalculating.”
Well, we finally got there. When I had a chance to relax, it hit me. That’s what Hashgacha Pratis is, or rather, it’s an excellent metaphor for Hashgacha Pratis. The satellite in the sky didn’t abandon us or forget about us. Even when we made mistakes it gently guided us back on track. It didn’t get tired of helping us and it didn’t get angry at us. But this is just a machine, a satellite connected to an electronic device in our car! How much more so, Hashem—the Creator of men and machines—He continually and mercifully guides us and helps us and NEVER forgets about us, even when all we hear is silence.
This is what the Rebbe MH”M said—that one of the ways that modern technology prepares us for the Era of Moshiach is by making concepts in Torah visual and real for us, as the prophet Isaiah says, that in the Era of Moshiach “The glory of Hashem will be revealed and all flesh will see it…”
At the Chanuka Live event in 5752, the Rebbe MH”M spoke about satellites specifically, how they too were created to reveal the glory of Hashem and that one of their main purposes is “to bring more unity to mankind; to enable one person to help another even when they are far apart, whether it be material help or spiritual help. Thus satellites help people to increase in matters of justice and fairness, peace and unity throughout the world.”
Isn’t that what Swords into Plowshares is all about?