It’s been 25 years since NASA launched the Hubble Space Telescope into orbit, and many are celebrating one of the greatest scientific tools mankind has ever had at its disposal.
Hubble is actually one of four “Great Observatories” NASA commissioned back in the 1980s, which were built to study different wavelengths of light and were launched between 1990 and 2003, according to a Huffington Post report.
Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope are the other three.
Hubble was sent into space on April 24, 1990, and it has four main instruments allowing it to view a range of lights, including visible, near ultraviolet, and near infrared. It is the telescope that has helped scientists estimate the age of the universe itself, discovered that those shining beacons of light we call quasars are actually blasted from black holes, and helped us better understand the notion of “dark energy” — and help us find out it exists at all.
A year later, the Compton Gamma Ray Observatory was launched into space, and its job was to study gamma rays from objects deep in space. Compton lived a short life: just 10 years later, NASA dumped it into the ocean.
The Chandra X-ray Observatory was designed to detect X-rays in hot regions of the universe in order to help astronomers study exploding stars and galaxy clusters. X-rays are absorbed by the Earth’s atmosphere, so the telescope had to be in orbit in order to see these X-rays, sitting about 86,500 miles from the Earth’s surface. It was launched in 1999 and continues to do its work today.
The last observatory, the Spitzer Space Telescope, was launched in 2003 and was designed to look for infrared light, allowing it to study failed stars, giant clouds of gas and dust, and organic molecules that could help us understand how life originated in the universe.
All together, these observatories allow us to come to a much deeper understanding of how the universe ticks.