A new device will study the origins of the Milky Way

A new device will study the origins of the Milky Way


Where do the stars in our night sky come from?

Scientists have loaded one of Earth’s most powerful telescopes with new technology that will show how our galaxy formed in unprecedented detail.

The William Herschel Telescope (WHT) in La Palma, Spain, will be able to measure 1,000 stars per hour until it has cataloged a total of five million.

A super-fast mapping device linked to WHT is analyzing each star’s composition and the speed at which it is moving.

It will show how our Milky Way was built over billions of years.

Professor Gavin Dalton of Oxford University has spent more than a decade developing the instrument known as the “Weave”.

He told me he was “very excited” to get going.

“It’s a fantastic effort by many people to make this possible and it’s great that it’s working,” he said. “The next step is the new adventure, it’s awesome!”

Weaving Instrument: It looks like a large metal disk traversed by fiber optic tubes pointing in all cardinal directions.  Robotic arms hover overhead.

Weave’s nimble robotic fingers precisely position a thousand optical fibers, each pointed at a star

Weave was installed on the WHT, perched high on a mountaintop on the Spanish Canary Island of La Palma. The name stands for WHT Enhanced Area Velocity Explorer – and that’s exactly what it does.

It consists of 80,000 individual parts and is a marvel of engineering.

For every spot in the sky that the WHT focuses on, astronomers identify the positions of a thousand stars. Weave’s nimble robotic fingers then carefully place a fiber optic — a translucent tube — at each precise spot on a disk that points to the corresponding star.

These fibers are actually tiny telescopes. Each captures light from a single star and directs it to a different instrument. This then splits it into a rainbow spectrum that contains the mysteries of the star’s origin and history.

All of this is done in just an hour. Meanwhile, optical fibers for the next thousand stars are positioned on the back of the plate, which turns over to analyze the next set of targets once the previous survey is complete.

Milky Way

Graphic: The Milky Way is surrounded by “dwarf” satellite galaxies

Our galaxy is a dense spiral vortex of up to 400 billion stars. But it started out as a relatively small cluster of stars.

It formed from successive mergers with other small galaxies over billions of years. As well as adding stars from the new galaxies joining ours, each merger shakes things up enough to result in brand new star formation.

Weave is able to calculate the speed, direction, age and composition of every observed star, essentially creating a moving picture of stars moving in the Milky Way. According to Prof. Dalton, backward extrapolation will make it possible to reconstruct the entire formation of the Milky Way in unprecedented detail.

“We will be able to track the galaxies that were absorbed as the Milky Way was built over cosmic time – and see how each absorption triggers new star formation,” he said.

dr Marc Balcells, who has overall responsibility for the WHT, told BBC News he believes Weave would lead to a major shift in our understanding of how galaxies form.

“We’ve been hearing for decades that we’re in a golden era in astronomy – but what the future awaits is far more important.

“Weave will answer questions astronomers have been trying to answer for decades, such as how many pieces come together to form one large galaxy and how many galaxies were united to form the Milky Way?”

control room

Instrumentation Specialist Dr. Cecilia Farina says Weave may discover a completely unexpected phenomenon

dr Cecilia Farina, an instrumentation specialist on the project, said she believes Weave will make astronomical history.

“There’s a tremendous amount of things we’re going to discover that we didn’t expect,” she said. “Because the universe is full of surprises.”

You can see Weave and other new telescopes in action in a short film, The Cosmic Hunters, on BBC iPlayer.

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