How Solar Eclipses Illuminate The Marvel Of Science

ON MONDAY, AUGUST 21, 2017, the world will go under, or so it might well feel like if you position yourself along a 70-mile-wide swath of the US from South Carolina to Oregon. From here you can witness the moon move in front of the sun in the middle of the day and darken the skies above you. A total solar eclipse is a spectacular event that has struck fear into people throughout history, and at the same time has enlightened us in our quest to understand the cosmos. Our ability to predict this year’s event with such specificity is thanks to scientific inquiries dating back thousands of years.

The ancient Greek historian Herodotus tells us that as the Medes and Lydians were fighting by the Halys River, day suddenly turned to night. They took it as a sign that the gods were angry, ceased their fighting, and thus peace was restored to the troubled region. Strikingly, Herodotus goes on to say that the star-gazing thinker Thales of Miletus had foretold of the phenomena. This is the first known account of an accurate prediction of a solar eclipse, and the first historical event that we can date back to a specific day: May 28, 585 BC. More importantly, the story hints at how Thales broke with mythological thinking and began to recognize nature as a series of immutable constants that the human intellect can hope to uncover, as opposed to a consequence of the unpredictable mood swings of gods.

The Greeks believed that Thales had foretold of an eclipse, at least to within the year that it happened. They must have been inspired by the prediction when they built on his ideas about a rationally ordered cosmos and created a new tradition of philosophical and scientific thinking. However, it was not until more than 2,000 years later, in the early 18th century, that the first precise prediction of a solar eclipse was made by astronomer Edmund Halley. Using Isaac Newton’s revolutionary theory of universal gravitation, Halley estimated an eclipse to within four minutes. In what was likely the most widely distributed broadside in England up to its time, Halley announced his finding publicly in 1715, shortly before the eclipse on May 3. He proclaimed the successes of science, and advised that rather than seeing the eclipse as something ominous, portending evil, “hereby they will see that there is nothing in it more than natural, and no more than the necessary result of the motions of the sun and moon”.

The connection between the development of scientific thinking and solar eclipses was further strengthened when Albert Einstein expanded on Newtonian physics by stating that gravity should not be understood as the sun pulling objects toward it. Rather, he theorized, the sun literally bends the curvature of space like a heavy object on a trampoline, and this causes things to fall toward it. If correct, he reasoned, the light from distant stars that pass by our sun will be bent twice as much as Newtonian physics had earlier predicted. To test Einstein’s theory, astronomer Sir Edmund Ellington and his team put up cameras in advance of a total solar eclipse on May 29, 1919. That way, they could see the light from distant stars that passed by close to the sun without the interference of the sun’s own bright light.

After spending six months evaluating their data from the solar eclipse, Ellington’s findings were published in The New York Times. From there the news went around the world that Einstein’s strange theory of general relativity had been proven correct. Almost overnight, Einstein became a household name.

The forthcoming American eclipse is unlikely to stand out in our collective memory as a symbol of scientific evolution and ingenuity the way the eclipses of 585 BC, 1715, and 1919 have. But next week’s event represents more than mere spectacle and media hype. More data will be collected from this eclipse than from any previous one in history, enabling us to better analyze such things as the sun’s upper atmosphere, or corona, which is visible only during a solar eclipse, and perhaps find clues as to why the corona is 300 times hotter than the surface of the sun. Next week’s eclipse can also help us to better predict space weather in order to protect astronauts and satellites.

It is one of the most formidable testaments to the marvel and achievement of science that we can predict with great confidence, and with accuracy measured in seconds, that such an awe-inspiring phenomenon as a total solar eclipse will happen on August 21, 2017—whether the gods are angry on that particular day or not.


Trees In The Amazon Make Their Own Rain

The Amazon rainforest is home to strange weather. One peculiarity is that rains begin 2 to 3 months before seasonal winds start to bring in moist air from the ocean. Now, researchers say they have finally figured out where this early moisture comes from: the trees themselves.

The study provides concrete data for something scientists had theorized for a long time, says Michael Keller, a forest ecologist and research scientist for the U.S. Forest Service based in Pasadena, California, who was not involved with the work. The evidence the team provides, he says, is “the smoking gun.”

Previous research showed early accumulation of moisture in the atmosphere over the Amazon, but scientists weren’t sure why. “All you can see is the water vapor, but you don’t know where it comes from,” says Rong Fu, a climate scientist at the University of California, Los Angeles. Satellite data showed that the increase coincided with a “greening” of the rainforest, or an increase in fresh leaves, leading researchers to suspect the moisture might be water vapor released during photosynthesis. In a process called transpiration, plants release water vapor from small pores on the underside of their leaves.

Fu thought it was possible that plants were releasing enough moisture to build low-level clouds over the Amazon. But she needed to explicitly connect the moisture to the tropical forest.

So Fu and her colleagues observed water vapor over the Amazon with NASA’s Aura satellite, a spacecraft dedicated to studying the chemistry of Earth’s atmosphere. Moisture that evaporates from the ocean tends to be lighter than water vapor released into the atmosphere by plants. That’s because during evaporation, water molecules containing deuterium, a heavy isotope of hydrogen made of one proton and one neutron, get left behind in the ocean. By contrast, in transpiration, plants simply suck water out of the soil and push it into the air without changing its isotopic composition.

Aura found that the early moisture accumulating over the rainforest was high in deuterium—“too high to be explained by water vapor from the ocean,” Fu says. What’s more, the deuterium content was highest at the end of the Amazon’s dry season, during the “greening” period when photosynthesis was strongest.

The tree-induced rain clouds could have other domino effects on the weather. As those clouds release rain, they warm the atmosphere, causing air to rise and triggering circulation. Fu and colleagues believe that this circulation is large enough that it triggers the shift in wind patterns that will bring in more moisture from the ocean, they report in the Proceedings of the National Academy of Sciences.

Scientists have studied the connection between trees and rain in the Amazon before. A 2012 study found that plants help “seed” the atmosphere for rain by releasing tiny salt particles. But the new study strongly supports the idea that plants play an important role in triggering the rainy season, says Scott Saleska, an ecologist at the University of Arizona in Tucson, who was not involved with the work. The deuterium provides a clear “fingerprint” for what plants contribute to the process, he says.

The findings also address a long-standing debate about the role plants play in weather, says Saleska, suggesting that they are more than just “passive recipients,” and that they instead can play an active role in regulating rainfall. If that’s true in the Amazon, Saleska says, climate scientists will need to take into account practices like deforestation when predicting regional changes in weather patterns. And curbing deforestation will be an important step for people to take in preventing drought.

Next, Fu will be studying rainforests in the Congo, to see whether the same process is happening.

International Technology Bank to launch operations this year

The International Technology Bank, which aims to strengthen science, technology and innovation capacities in the least developed countries, will launch operations this year in Turkey, Science, Industry and Technology Minister Faruk Özlü said. Özlü said that a United Nations delegation has come to Turkey to evaluate preparations of the International Technology Bank site to be established in Gebze.

Explaining that a host country agreement between Turkey and the U.N. will be prepared and signed, Özlü said that following the signing, employees and office space in Gebze will be determined and the International Technology Bank will launch operations this year.

Özlü told Anadolu Agency (AA) that the International Technology Bank in Turkey is being established under the leadership of the U.N. in coordination with the Scientific and Technological Research Council of Turkey (TUBİTAK).

Recalling that President Recep Tayyip Erdoğan previously announced a commitment package at the United Nations Conference on Least Developed Countries in 2011 when he was still prime minister, Özlü said that one of the commitments in science and technology fields in the country is the establishment of an international hub that will take over the role of the technology bank for least developed countries.

Özlü said that a high-level expert panel was set up to provide consultancy and suggestions during the establishment process of the bank and that evaluation conferences were held. Recalling that the proposals for the operation and structuring of bank were presented and that it was recommended the bank be established in Turkey during the meetings, Özlü said that it was decided at the 70th U.N. General Assembly that the International Technology Bank be established in Gebze.

Bank employees to be determinedÖzlü said that the U.N. delegation visited the Science, Industry and Technology Ministry, adding that the issues of the host country agreement as well as financial, aid in kind agreement were discussed.

Özlü pointed out that the U.N. delegation will go to the U.S. after Turkey, adding that the host country agreement between Turkey and the U.N. will be prepared and signed afterward. “The signing is expected to be held this month. After the signing, office space and employees in Gebze will be determined and this year the International Technology Bank will launch its activities,” Özlü said.

Stressing that Turkey has pledged its full support for the International Technology Bank project, Özlü said that financing is voluntary, informing that the donor country, Turkey, will provide financial support of $2 million annually for the first five years and that following the establishment, many U.N. member countries, as well as world-famous technology companies, are expected to support the bank.

Özlü underlined that when the International Technology Bank commences operations, need analysis will be carried out for the least developed countries and service will be provided in line with the shortcomings. Indicating that the countries will be given training and support on the establishment of governance mechanisms and the development and implementation of science and technology policies, Özlü added that they wish Turkey to contribute to the efforts in reducing income disparities in the world and the great differences in development levels.