In 1623, the Italian physicist Galileo Galilei made a groundbreaking discovery by observing the Sun with a telescope for an entire summer. This observation led him to deduce that the sun was not a perfect sphere, but had spots that moved over time. Galileo also discovered craters on the Moon, named the four main satellites of Jupiter, and intuited that Saturn had rings. This use of the telescope opened up new possibilities in astronomy, leading astronomers to design instruments that could capture more light and observe celestial bodies more clearly.
Today’s telescopes continue to push the boundaries of scientific discovery. One of the most remarkable modern telescopes is the Gran Telescopio de Canarias (GRANTECAN) located in La Palma, Spain. With a main mirror measuring 10.4 meters, it is currently the largest optical telescope on Earth. Its advanced instrumentation allows it to operate in both optical and infrared ranges, revealing celestial bodies like extrasolar planets and dim galaxies. Another impressive observatory is the Atacama Large Millimetre Array (ALMA) in Chile, which is the largest interferometer on the planet. ALMA’s 66 antennas enable high-resolution observations of protoplanetary disks, galaxies in formation, and the first image of a black hole.
Beyond Earth’s surface, the James Webb Space Telescope is a collaborative effort between 14 countries operated by the European, American