Since the time when the earliest humans looked up at the night sky and tried to make sense of the Heavens, humans have longed to understand the splendor and magic of the night sky.
One of the first people to point a telescope at the night sky was the Italian astronomer Galileo. Galileo spent many nights observing the planet Jupiter in the year 1610. He was the first to observe and record the motions of Jupiter’s largest four moons, Ganymede, Europa, Io, and Callisto. These observations proved that not all celestial bodies orbited around the Earth, and eventually led to the conclusion that the Earth is not the center of the universe.
Since that time technology has continued to advance at a rapid pace. Our ability to see further into the universe with greater detail has continued to improve to this day. From Galileo’s 2 inch telescope in 1610 to the great space telescopes and ground observatories of today’s modern astronomy, we now live in the golden age of astronomy. Large ground-based observatories are now operating across the globe, taking measurements of the universe in multiple wavelengths.
Looking across the deepest reaches of space is actually a look back in time to the deepest history of the universe. Because light travels at a fixed speed, it takes time for light from distant objects to reach us on Earth. The light from the Sun takes 8 minutes to reach us on Earth. The reflected light from Pluto takes 5 ½ hours to arrive at Earth. Light from the nearby Andromeda Galaxy takes 2 ½ million years to reach Earth, meaning we see that beautiful galaxy as it appeared 2 ½ million years ago. The further out in the universe we look, the further back in time we see.
The space-based Hubble telescope and now also the James Webb telescope are opening new doors to see the universe in its earliest era. New ground-based telescopes are creating new surveys of the universe to try to understand the strange features of Dark Matter and Dark Energy.
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