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Arecibo Observatory is shutting down — here are some of the most groundbreaking discoveries it inspired, including one that led to a Nobel Prize

Arecibo Observatory is shutting down — here are some of the most groundbreaking discoveries it inspired, including one that led to a Nobel Prize
  • The National Science Foundation (NSF) has deemed the radio telescope housed within the Arecibo Observatory no longer fit for function.
  • As one of the biggest telescopes in the world, and once the most powerful radio telescope in existence, the Arecibo Observatory has been responsible for groundbreaking discoveries in the field of astronomy.
  • This includes discovering the first planets outside our solar system, ice on the poles of Mercury, and even evidence of the very first binary pulsar that led to a Nobel Prize in Physics.
The Arecibo Observatory is one of the biggest in the world, responsible for some of the most crucial discoveries about outer space — including one that led to a pair of scientists winning the coveted Nobel Prize in Physics.

However, the legendary telescope will now be shut down and taken apart due to recent infrastructure issues.

The downfall of one of the biggest telescopes in the world

The astronomical observatory was the largest single-unit radio telescope in the world until China’s Five-hundred-metre Aperture Spherical radio Telescope (FAST) began operations in 2016.

Built in the early 1960s, the telescope had been operational for over 57 years when it sustained two cable failures. It has rendered its massive 305-meter wide radio dish unstable. The separation of the cables has also damaged the radio dish’s metal panels.

The gaping holes left behind are so big that they can be spotted from outer space.

In light of the damages and the resulting safety issues, the National Science Foundation (NSF) announced that it would be decommissioning the Arecibo telescope on November 19.

"According to engineering assessments, even attempts of stabilization or testing the cables could result in accelerating the catastrophic failure," Ralph Gaume, director of the NSF's astronomy division, said during the news conference.

Here’s a quick look at some of the legendary discoveries made using the Arecibo telescope that changed our understanding of the universe:


Arecibo’s first significant discovery — Revealing that Mercury only takes 59 days to complete its orbit around the Sun.

Arecibo’s first significant discovery — Revealing that Mercury only takes 59 days to complete its orbit around the Sun.
NASA

Before the 1960s, scientists believed that Mercury took 88 days to complete its orbit around the Sun. It was also assumed that Mars always faces the Sun in the same direction.

However, using observations collected by the radio telescope housed within the Arecibo Observatory, researchers could invalidate those theories. They discovered that Mercury takes only 59 days to complete its orbit around the Sun.

While Mercury isn’t tidally locked, it does turn; and it completes three rotations in every two orbits.

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The Nobel Prize-winning discovery of the first-ever binary pulsar in 1974

The Nobel Prize-winning discovery of the first-ever binary pulsar in 1974
Arecibo Observatory

The first binary pulsar — a highly magnetized rotating star orbiting another — was first discovered at the Arecibo Observatory by Joseph Taylor and Russell Hulse in 1974.

The more exciting detail about this discovery was finding out that the orbit of the two stars was shrinking at a rate of 1 centimetre per day. The shrinkage was attributed to the loss of orbital energy due to gravitational radiation — or gravitational waves — predicted by Einstein’s General Theory of Relativity.

This discovery was crucial for testing the theories of gravity and led to both the scientists winning a Nobel Prize in 1993.

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Discovery of the first planets outside the solar system in 1992

Discovery of the first planets outside the solar system in 1992
Arecibo Observatory

For a long time, scientists hypothesized that there had to be more planets in the universe than just the ones that existed within the solar system. But, evidence to prove that theory was scarce.

That is, until 1992. That’s when the Arecibo Observatory was able to capture the very first exoplanet. In subsequent years, it was able to discover an entire planetary system around pulsar PSR 1257+12.

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Creation of the first-ever radar maps showing the surface of Venus

Creation of the first-ever radar maps showing the surface of Venus
Arecibo Observatory

Past attempts at capturing the surface of Venus were made using optical cameras. These observations could not penetrate through the planet’s top layer of thick clouds, leaving what lay under the surface a complete mystery.

However, since Arecibo did not rely on optical images but radio waves, it was able to break through the haze and create the first-ever radar maps of Venus’ surface.

This discovery led to the prospect that it may even be possible to map the surface of Venus at resolutions down to 2 kilometers. The US National Aeronautics and Space Administration (NASA) subsequently agreed to upgrade the telescope and provide funds for a 420 kilowatts (kW) transmitter for a closer look.

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Discovery of the first-ever millisecond pulsar in 1982

Discovery of the first-ever millisecond pulsar in 1982
Arecibo Observatory

Observations from the Arecibo Observatory also led to the detection of the first-millisecond pulsar, PSR B1937+21. It was discovered in 1982 by DC Backer, Shrinivas R. Kulkarni, Carl Heiles, MM Davis, and WM Goss.

Spinning at roughly 641 times per second, it remains the second fastest-spinning millisecond pulsar of the approximately 200 discovered after that.

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Discovery of ice on the poles of Mercury

Discovery of ice on the poles of Mercury
Arecibo Observatory

NASA may have caught the first-ever photos of ice on Mercury poles, but that only happened in 2014.

Observations from the Arecibo Observatory had already detected water on the North and South of the planet closest to the Sun over two decades earlier in 1992.

It showed that the ice persists in Mercury's shadowed craters despite the high temperatures of nearly 426 degrees Celsius on the planet’s surface.

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