There are several “telescopic iris” looking at the sky for us

Over the past four centuries, since Galileo observed the stars with his telescope, we have taken a cosmic journey spanning more than 13 billion years.

The iris is a thin, circular structure that exists in the eyes, which gives them a color that amazes us. It is responsible for controlling the diameter and size of the pupil, at its center, and then for the amount of light that enters the eye and hits the retina.

Radiated by stars and other bodies and cosmic events, in a characteristic way over time, electromagnetic radiation floods space, at least since 380 thousand years after the “Big Bang” that originated our Universe.

How do we know this? Among other data, through the cosmic background radiation captured through other iris, these radiotelescopic ones, which we were technologically building and placing in high mountains (where the air is thinner and drier, and far from the light pollution of large urban centers), or in space telescopes placed in certain orbits (where there is no air or much dust).

There are several “telescopic irises” looking at the sky for us lowly myopic cosmic ones. Astronomical and astrophysical sciences today benefit from satellites which, with precise and appropriately very sensitive instrumentation, scan specific zones of almost the entire electromagnetic spectrum.

In 2013, the Planck telescope recorded, throughout the space around it and for 15 months, the fossil record of the first photons (particles of light) that appeared in our Universe, after a journey of more than 13 billion years until reach us.

These photons reach us in electromagnetic radiation with the frequency of microwaves and correspond to what is called the cosmic background radiation. Through the data obtained by the Planck satellite telescope, we were able to “see” the first light that radiated after the “Big Bang”.

Over the last few decades, other telescopes incorporated in satellites “see” the Universe at other frequencies. Some examples are: the Herschel in the far infrared; the JWST in infrared; the Hubble Space Telescope in the visible; Gaia in the near infrared, visible and ultraviolet; the XMM-Newton on x-rays; o in gamma rays; Et cetera.

Each of these “telescopic irises” have precise scientific missions and have contributed decisively to our conception of the Universe, from the most distant galaxies to the black holes at the center of our galaxy, from the amazing nebulae remnants of supernova explosions, to the pulsars of neutron stars, authentic lighthouses in the cosmic night.

Other irises advance towards the stars: the Voyager and Pioneer probes which are the human objects farthest from Earth today (Voyager 1 lies on the farthest known frontier of our Solar System, more than 120 times the distance from Earth to Earth. Sun).

Over the last four centuries, since Galileo observed the stars with his telescope, we have made a cosmic journey of more than 13 billion years, decoding the signals carried in electromagnetic waves by photons, like cosmic pilgrims, finally captured by the “iris technologies” that we've built.

One of the largest is the ALMA radiotelescope, from the European Southern Observatory, installed on the desert plateau of Atacama, Chile.

This opens up new pupils in “technological irises” which, despite not impressing the retina of our eyes, scare away our neuronal pathways. With the brain in possession of current knowledge and technology, our knowledge of the past expands and we look to the future horizon of a new cosmos invisible to the nakedness of our eyes.

Today, we can paint the sky with a rainbow that starts with gamma radiation and ends with our radio waves!


Author Antonio Piedade
© 2021 – Science in the Regional Press / Ciência Viva