How 2 European satellites created the first artificial solar eclipse – Firstpost

Solar eclipses are rare astronomical marvels. But it seems that won’t be the case anymore. Two European satellites created an artificial total solar eclipse in space by flying in precise and fancy formation, providing hours of on-demand totality for scientists.

Wait what! The European Space Agency (ESA) released the eclipse pictures at the Paris Air Show on Monday (June 16).

All about the ‘artificial total solar eclipse’

But how was it made possible? Flying 492 feet (150 metres) apart, one satellite blocked the sun like the moon does during a natural total solar eclipse as the other aimed its telescope at the corona, the sun’s outer atmosphere that forms a crown or halo of light.

In this experiment, one of the satellites, called the Occulter, carried a 1.4-metre-wide carbon fibre and plastic disc, which blocked out the sun’s light for the second satellite, the Coronagraph, which was equipped with a camera and scientific instruments.

According to Associated Press, it was an intricate, prolonged dance requiring extreme precision by the cube-shaped spacecraft, less than five feet (1.5 meters) in size. The flying accuracy needed to be within a mere millimetre, the thickness of a fingernail.

This $210 million mission, dubbed Proba 3, has generated 10 successful solar eclipses so far during the ongoing checkout phase. The longest eclipse lasted five hours, said the Royal Observatory of Belgium’s Andrei Zhukov, the lead scientist for the orbiting corona-observing telescope. He and his team are aiming for a wondrous six hours of totality per eclipse once scientific observations begin in July.

Why this is significant

For scientists, this is a thrilling result. Zhukov said, “We almost couldn’t believe our eyes. This was the first try, and it worked. It was so incredible.”

He added that what makes this experiment even more significant is that in past attempts the sun-blocking disc was always on the same spacecraft as the corona-observing telescope. However, this time the sun-shrouding disk and telescope are on two different satellites and therefore far apart.

This will allow scientists a better look at the part of the corona closest to the limb of the sun.

Now, Zhukov anticipates an average of two solar eclipses per week being produced for a total of nearly 200 during the two-year mission, yielding more than 1,000 hours of totality. That will be a scientific bonanza since full solar eclipses produce just a few minutes of totality when the moon lines up perfectly between Earth and the sun — on average just once every 18 months.

The sun continues to mystify scientists, especially its corona, which is hotter than the solar surface. Coronal mass ejections result in billions of tonnes of plasma and magnetic fields being hurled out into space. Geomagnetic storms can result, disrupting power and communication while lighting up the night sky with auroras in unexpected locales.

Damien Galano at ESA was quoted as telling New Scientist, “These images will improve our understanding of the sun’s corona physics as well as help us to better understand the solar wind and coronal mass ejections, which affect space weather.”

With inputs from Associated Press