About four centuries ago, an invention was born that was to redefine our place in the universe. Blacked out at the time as “the most diabolical instrument in history,” the telescope shook society to its roots. Looking up at the sky, we convinced ourselves that we were the center of creation, and there were reasons for this: From our perspective, everything seems to revolve around the Earth. If someone challenged this notion of the world, their voice would be silenced by the religious powers that defended it. But, between 1608 and 1609, a small tube with two crystals at its ends changed everything .
Since ancient times it was known that a glass sphere can be used to magnify images, but it was not until much later that someone decided to assemble two lenses in a tube and look through it; although the date, place and author seem to be not very clear. The Dutch are leaning towards October 2, 1608 , when Hans Lippershey patented an instrument known as a kijker , which means ‘lookout’. Lippershey was German, lived in Holland and patented his invention in Belgium, for which several countries claim the honor of his authorship. However, as Darwin said, “in science the credit is the one who convinces the world and not the first one who has the idea” ; and that is why Italy took the glory thanks to Galileo Galilei .
The improvements introduced by the Italian genius, who used a convex lens for the objective and a concave for the eyepiece , allowed the device to be used as an astronomical instrument. The German Johannes Kepler was the first to use two convex lenses that focused the rays at the same point, creating the refractor telescope in 1611. Galileo went to the powerful and showed them the moons of Jupiter and the ears of Saturn with the objective of “ let them see ”and trusting that it was not against the Church because its purpose“ is not to determine how the heavens are going, but how to go to them ”. However, Galileo would spend his last days under house arrest and intellectually forgotten.
The same year that he died, Isaac Newton was born in the United Kingdom, who would be responsible for finishing Galilei’s task and giving a conception of the universe that survived more than 250 years , until the arrival of Einstein. Newton used mirrors instead of lenses to focus light and form images, giving rise to the reflecting telescope and opening the doors of the universe to mere mortals. Telescopes allowed us to travel back in time since in astronomy, the further we look, the further we go into the past.
To read the first chapter (or even the prologue) of the biography of the cosmos, larger and larger observatories with ultra-polished mirrors that collect photons in industrial quantities have been needed. In the late 1970s, astronomers’ instruments were not fulfilling their ambitions, and many thought that the 5-meter Hale telescope (California) was the limit. When Russia built a 20-foot mirror in 1976, the images obtained were aberrant.
It was a Berkeley physicist, Jerry Nelson , who came up with the solution by joining hexagonal mirrors in a beehive pattern . The design used adaptive optics technology that corrected atmospheric disturbances and for that a high-power supercomputer was needed. Although initially thought impossible, the twin Keck I and Keck II telescopes opened their lids in the 1990s and made segmented mirrors the leaders in optical mega-scopes, with numerous similar projects quickly emerging.
In 1990 , the Discovery shuttle placed the Hubble telescope 593km high , capable of capturing 15,000 galaxies in a single photograph and which, being free from the effects of atmospheric turbulence, has been the largest source of information on interstellar space. Returning to Earth, the Very Large Telescope of the European Southern Observatory measures 8.2 meters in diameter and is the culmination of optical interferometry. A device Galileo would be proud of.
The next generation of mirrored telescopes is expected to be over 40 meters in diameter and can even go as high as 100 meters. The next step that will take us forward is to place eyes capable of glimpsing the first moments of the universe into orbit. Perhaps, as with Galileo’s instrument, these new discoveries will force us to discard everything we took for granted. But until then, we’ll still be here, wondering what else the stars hide .
