The great solar eclipse arrives

On July 2 will be held the great solar eclipse of Argentina 2019, a unique astronomical event that can be contemplated in all its splendor within a band that runs through 6 provinces. In the rest of the country, this will be seen in part. The shadow of the Moon will cross the national territory from east to west at a speed of 3.5 km per second. The phenomenon will last two hours, but it will take two minutes: it will be when the complete superposition of the stars will take place at night in broad daylight.

A solar eclipse is only possible in the new Moon, when the Sun, our satellite and the Earth are aligned and the shadow projected by the lunar star in space touches our planet . The completion and completion time will depend on the location of the observer. The deadline will be extended between 16:25 and 18:45. The maximum eclipse will take place between 17:30 and 17:45.

Every 18 months, there is a total eclipse somewhere on the planet, but it can run out for many years before there is another pbad on an inhabited region. The last visible was August 21, 2017 in the United States. The next will take place on December 14, 2020 and will be seen again in Argentine Patagonia.

"It sounds incredible, but a fact as commonplace as an object that pbades in front of another product one of the most extraordinary shows." A total eclipse of the Sun begins with the growing discomfort of seeing the silhouette of the Moon mask the bright disc of the sun. When it is about to completely cover it, it is perceived at the horizon, on the west side, the darkness of the Moon's shadow coming close to a speed supersonic, suddenly, there is a twilight and a night in broad daylight. and you can see the stars, "said Guillermo Abramson, professor at the Atomic Center of Bariloche / Balseiro Institute.

The eclipse will be partial in much of our territory, while the path of the shadow, where the sun will be completely hidden, will include a band that will cross from west to east the provinces of San Luis, La Rioja, San Juan , Cordoba Santa Fe and Buenos Aires.

To see the totality, it will be necessary to be in the zone where the shadow will cross: the innermost fraction of the shadow, where all the solar disk is covered. The width of this band varies in each eclipse because it depends on where on the Earth it occurs. On this occasion, it will have a width between 145 and 130 km and a speed of 12,600 km / h when crossing San Juan.

"Solar eclipses are possible because the moon, 400 times smaller than the Sun, is 400 times farther than the incandescent star.By this angular chance, the Moon, which describes an elliptical movement around the Earth, seems large enough in the sky to completely cover the Sun during total eclipse.If the Moon is in its furthest position, it can not completely cover it and there is an annular eclipse, where there is a ring bright around the moon, "says Diego Galperín, doctor of science teaching at the National University of the Center. from the province of Buenos Aires (UNICEN).

In these two and a half minutes where the three stars are aligned, a twilight will be seen in the horizon and you will be able to see the diffused solar corona, the external atmosphere of the Sun that can only be perceived during the whole.

"Above the visible surface of the Sun (fotosfera) extends the solar atmosphere, which we call" Corona. "This develops in the interplanetary space forming the" heliosphere. " Because of its low density, the crown shines much less than the solar surface (in visible light, but not in other wavelengths) and is therefore generally not visible to the human eye. a total eclipse of the Sun, the moon completely covers the solar disk and the crown is visible in all its splendor, "says Alberto Marcos Vásquez, researcher at the Solar Physics Group of the Institute of Astronomy and Physics of space (IAFE, UBA-CONICET).

Due to its position, San Juan is considered the best place to observe this eclipse in Argentina, as it takes place in the winter and a few minutes before sunset. Public activities organized by the project Miradas al cielo of the National University of Rio Negro, the Institute of Astronomy and Space Physics of the UBA and the Astronomical Observatory Felix Aguilar of the National University of San Juan, include lectures and a subsequent observation of the phenomenon.

Precautions to take in the face of the eclipse

The sun should never be observed without eye protection as the retina can be damaged even without discomfort. "There is a risk of irreversible damage to sight, and neither binoculars nor a telescope should be used, because the damage is immediate and inevitable." During the entire partial phase (or any day of the day) Year), you can look with eclipse glbades or with a mask mask 12 or darker (they are cheap and bought in hardware stores) Neither black glbades, nor X-rays, nor paper If you are traveling in the region of total eclipse, remember that during the total phase, it can and should be observed with the naked eye, without filter, to enjoy of the solar corona and the entire show, "warns Abramson.

Source: Clarín