Astronomers have been able, for the first time, to detect collisions with dead suns known as neutron stars, thanks to a new, reliable telescope. The telescope is the Gravitational Wave Optical Transient Observer (GOTO).
Goto, located above the clouds on the Spanish volcanic island of La Palma, will now systematically hunt for a collision event. Neutron star collisions are important to our understanding of the universe.
They are believed to have created the heavy metals that form Earth-like stars and planets billions of years ago. The light from the collision was only visible for a few nights, so telescopes had to race to find it.
Astronomers saw one of these collisions in 2017, but most found it by luck.
“When really good identities come to the fore, everything has to be maximized,” said Professor Danny Steighs from the University of Warwick.
“Speed is of the essence. We are looking for something short-term, no longer than their disappearance,” he continued.
Neutron stars are so heavy that a tiny teaspoon of their material weighs four billion tons. The telescope allows astronomers to effectively open one of those tiny sections to see what’s inside.
To see the sky clearly, the telescope is mounted on a mountain top, with dozens of instruments of all shapes and sizes, each studying a different phenomenon.
When the twin domes open, they reveal two jet-black batteries of eight cylindrical telescopes fused together, the structure more like a rocket launcher. Each battery covers each swath of sky above itself by rapidly rotating vertically and horizontally.
A neutron star is a dead Sun that has collapsed under its enormous weight, destroying the atoms that once made it shine. They have a strong gravity so they are attracted to each other. Eventually, they fell together and merged.
When this happens, they produce flashes of light and shockwaves and powerful waves throughout the universe. That event shook up everything in the universe, which includes, invisibly, the atoms within each of us.
Shock waves, called gravitational waves, distort space. When it is detected on Earth, the new telescope kicks into action to pinpoint the exact location of the flash.
Operators find it within hours, or even minutes, of detecting a gravitational wave. They took pictures of the sky, then digitally erased the stars, planets and galaxies that were there at night. Every point of light that did not exist before can be a colliding neutron star.
It usually takes days and weeks, but now it has to be done real time. It is a huge task, which is done using computer software.
“You would think that this explosion was very energetic, very bright, it should be easy. But we have to search a hundred million stars for the one object we are interested in. We have to do it very quickly because that object disappears.” In two days,” said the professor. Astrophysicist Dr. Joe Lyman.
The team is working with other astronomers to study the collision in more detail. Once they have determined the collision, they turn to larger and more powerful telescopes around the world. It investigates collisions in greater detail and at different wavelengths.
“This process tells us about physics to the extreme,” explains Dr. Lyman.
The top of the mountain brings astronomers a little closer to the stars. “With the telescope, they have a new way of looking at the universe,” said GOTO instrumentation scientist Dr. Kendall Ackley.
Traditional astronomy is all about luck. He concluded, “We no longer expect new discoveries. Instead, we are told where to find them, and to piece together what is in the universe.”