Astronomy in the Past Fifty Years

Black holes, echoes from the early universe, colliding galaxies – astronomy news stories reveal an amazing universe. This is a great period of astronomical discovery.

There have been two other such periods in astronomy, each marked by openness to learning and the development of new tools. The Classical Period (about 500 BC to about 100 AD) had the astrolabe and its application to the emerging field of geometry. The Renaissance, spanning the works of Copernicus around 1543 through Newton in the early 18th century, developed accurate clocks, the printing press (to disseminate information), and the telescope, as well as the Newton’s theoretical insights.

Three important tools have driven the explosive rate of discovery during the past 50 years: the computer, space satellites, and high-sensitivity digital cameras. These have allowed us to test theoretical predictions made by early 20th century work in quantum physics and relativity.

The computer made it possible to do calculations and process data that could not be handled previously, and allowed astronomers to control much larger telescopes. Before the computer, the largest telescope was the 200-inch instrument on Mt. Palomar. Older telescope mechanisms rotate only along one axis to compensate for the earth’s rotation, and require rigid, heavy supporting structures. With computer control, modern telescopes move along multiple axes, allowing more flexible, lightweight design.

Our atmosphere is a distorting filter, passing only visible light and some infrared and radio waves. To avoid distortions (think of heat waves above a parking lot on a summer day), you must get above the atmosphere. Satellites have given us spectacular views, such as the colorful images from the Hubble Telescope. They have also opened windows in infrared, ultraviolet, and x-ray, which are blocked by our atmosphere. These windows reveal unexpected views of the high energy radiation pouring from exotic objects and violent phenomena in the universe. Satellites have also provided clear views of bodies in our own solar system.

Modern telescopes enhance the capability of the human eye. A telescope acts as a light funnel, gathering much more light into our eyes. However, the human retina is an inefficient light detector. Photographic film was a significant improvement, but the CCD (charge coupled device – the chip at the heart of a digital camera) approaches 100% efficiency. With the CCD, the 16” telescope at GTCC’s Cline Observatory can almost “see” as much as the Mt. Palomar 200-inch could see before the CCD.

With these tools and accompanying theoretical advances, astronomers during the past 50 years have come to understand the life of a star, peer into stellar nurseries, observe the spectacular explosions of dying stars, and discover such astronomical exotica as quasars, pulsars, black holes, colliding galaxies, and more. Astronomers can now measure the age and make-up of the universe, learning that it is mostly composed of strange and unknown dark matter and dark energy. Like the universe itself, our knowledge of the cosmos has accelerated in its expansion over the last half century, but we have also discovered there is more to learn than ever imagined.

Aaron Martin is Astronomy Professor Emeritus at GTCC, and was the driving force behind the development of GTCC’s astronomy program and the Cline Observatory on the Jamestown campus. He has always inspired his students and visitors to the observatory to “keep looking up!”