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.
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, and Canadian space agencies. Despite having a smaller mirror compared to ground-based telescopes, the James Webb has the advantage of being outside the Earth’s atmosphere, capturing sharp images of distant objects. Its research goals include studying the formation of the first galaxies and observing the birth of stars and planets. The James Webb has already provided astounding images of the oldest known galaxy and planets in our solar system.
These advanced telescopes have revolutionized our understanding of the cosmos, allowing us to see further and explore the universe in ways previously unimaginable. From Galileo’s groundbreaking observations to the cutting-edge technology of modern observatories, telescopes continue to push the boundaries of scientific discovery.