CosmoCaixa invites us to look at the sun: don't worry, there are five billion years left

A visitor passes before an image of the sun in the exhibition that invites us to rediscover the star at Cosmocaixa, in Barcelona. Andreu Dalmau (EFE)

“A message that synthesizes the exhibition?: look at the sun again (not directly, of course)”.

This is how the particle physicist and curator of the new CosmoCaixa exhibition

, the British Harry Cliff, when asking him for a summary explanation of the objective of the exhibition.

There is no rush, although the exhibition that has been inaugurated on Tuesday afternoon can be visited until October 16, the sun will be there for us to observe another five billion years, what remains of a brilliant existence which is exactly, year up year down, in the middle.

As the sun nears its end and becomes a red giant star, its outer layers will expand beyond the orbit of Venus and we will have a definitely hot day on Earth.

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The exhibition, with a hundred objects as varied as a Babylonian tablet that mentions sunspots, a pre-Columbian mask in the shape of the sun and one of the solar panels that President Jimmy Carter had placed on the roof of the White House in 1979 during the energy crisis shouting “no one can seize the sun from us” (Reagan had them removed), aims to make people aware of this wonder and explain its mysteries.

A wonder, the sun, almost inconceivable in its titanic dimensions (its mass, two billion million million tons, is 99.9% of the total mass of our solar system, including all the planets, their moons, rings , asteroids and comets), its power and its jupiterine violence that light gives us (the sun is the only body in the solar system with its own light,

Originally produced by the Science Museum in London and co-organized with the La Caixa Foundation -which thus begins a collaboration with the British museum and has added its own material-, the exhibition is seen for the first time outside the United Kingdom.

It is divided into four areas that offer a general overview of our relationship with the sun.

The first explains how our star has served to define and measure time, and exhibits different sundials, including a very simple, portable, shepherd's, as well as an illuminating model of how the solstices are perceived at Stonehenge.

The second section is about

and remember that the star has been seen as a source of well-being and, thanks to the bactericidal capacity of its light, capable of curing diseases such as tuberculosis and rickets.

But it is also pointed out that from the 60s of the 20th century the dangers of overexposure to solar radiation and the need to protect themselves have been discovered.

Among the items on display are such curious things as an old sanatorium car for putting tuberculous children in the sun and a stretcher-refrigeration unit for restoring pilgrims to Mecca suffering from heat stroke.

Also holiday posters and an interactive device with which you can virtually try on different types of sunglasses, including wooden Eskimos and RAF fighter pilot sunglasses from 1941.

The third section deals

, explaining the various ways of harnessing the light and heat of our star, from mirrors to silicon solar cells or new photovoltaic materials such as pervoskite.

The old dream of recreating the power of the sun stands out - nuclear fusion, of hydrogen into helium: the sun is a thermonuclear reactor in gravitational confinement - which would definitively solve energy problems with a practically inexhaustible source of clean energy.

In this aspect, a prototype of one of the first fusion reactors is exposed, the ZETA (Zero Energy Thermonuclear Assembly) of 1958, which did not work.

The last section is devoted to the observation and understanding of the sun, a process that begins scientifically with the invention of the telescope, although there are precedents such as the aforementioned Mesopotamian tablet.

In this regard, Commissioner Cliff, who combines his scientific status with an enviable capacity for anecdotes, especially in this demanding context, explained that when there was an eclipse of the sun, the Babylonians inverted the hierarchy and the king became a worker and one of these was dressed as a king.

Next, they sacrificed the poor impostor in the consideration that in this way they would get rid of all the negative energy that he had accumulated during the occultation of the sun.

Galileo already saw sunspots (dark because they are cooler,

at 3,800 degrees) that provoked an intense interpretive debate.

The Swabian Jesuit and astronomer Christoph Scheiner confronted Galileo, considering that the spots must be shadows of bodies on the surface of the sun, since the star king could not have any blemish.

Later prominences were also discovered in the sun whose surface is anything but smooth and pleasant.

On the tour you can admire drawings and pioneering solar photos of hypnotizing beauty, and, among other devices, the Kew photoheliograph, from 1857, the first device to photograph the sun.

Solar storms are explained and there is a space dedicated to the storm of September 1859 whose start in a gigantic explosion, the first observed solar flare, was detected by the astonished English astronomer Richard Carrington.

The phenomenon, baptized the Carrington event, caused the most intense magnetic storm that is remembered in the terrestrial records.

Northern lights were seen even in the tropics, you could read at night with the light from the sky and the ship Southern Cross sailed in a sea of ​​luminosity so strange that he thought he was in hell.

Such a storm would be catastrophic today:

we would be left without electricity and the satellites would stop working (in 1857 the telegraph was disabled).

A very eloquent display case contains a series of objects and the visitor has to select which ones they would choose to survive a solar storm.

The answer is that you have to discard the silver foil hat, and keep the preserves, the map, the flashlight.

The camping gas is fine and from a book that surprisingly features in the set -

by Lucie Green-, it is said that “a good book can be useful”.

A section explains the different space missions to the sun, 149 million kilometers from Earth, including the latest, those of the Solar Orbiter and Parker Solar Probe probes, the one that has come closest and that last December entered the solar atmosphere ( the crown), "touching" the sun for the first time in history.

The ships carry shields made of, among other materials, pulverized animal bone.

The exhibition offers in a last spectacular area the possibility of closely observing the sun.

An audiovisual with real-time images of the star in different wavelengths of light and in very high resolution allow us to witness the sun in all its fascinating splendor from a privileged vantage point 36,000 kilometers above the Earth (the position of the Solar Dynamics spacecraft NASA's Solar Observatory, DSO. And gawk at a coronal mass ejection, twisting magnetic fields, or the transits of Venus and Mercury. Those things you'd think only a Nexus replicant can see. Sitting in the dark in front of the huge projection, in a stupefied and overwhelmed way like the protagonist of

or the characters of

, one feels insignificant, vulnerable, amazed, strangely excited, and grateful.

"And the world you bathe in your pure light, / vivid you throw the day from your forehead, / and, soul and life of the world, / your record in majestic peace sends".