A MeerKAT type dish (Wikipedia commons)
  • The R4.4 billion MeerKAT radio telescope is being launched on Friday.
  • It will eventually become part of the Square Kilometre Array (SKA), the largest scientific instrument ever.
  • Hydrogen is top of MeerKAT’s watch list


On Friday, South Africa will cut the ribbon on its shiny new radio telescope, MeerKAT. This R4.4 billion, 64-dish radio telescope will listen to the relatively weak signals from space to help scientists understand what is going on in the far reaches of the universe.

It will eventually become part of the Square Kilometre Array (SKA) which, when complete, will be the world’s largest radio telescope (and the largest scientific apparatus ever made) with dishes and antennas in South Africa and Australia.

But until then, MeerKAT will be doing some science of its own. 

“An area of study that encompasses a lot of our science is the study of hydrogen throughout the history of the universe,” says Fernando Camilo, chief scientist of the South African Radio Astronomy Observatory.

Looking into the past

One of the MeerKAT surveys, called LADUMA, will study a patch of sky and piece together how hydrogen has been behaving for about two-thirds of the age of the universe. Hydrogen has been present for most of the universe’s history, and has a characteristic wavelength (21cm).

Astronomers can still pick up the faint signals left over from this ancient hydrogen, although they have become distorted as they have travelled.

“Through the hydrogen-emission line, we will be able to probe two thirds of the history of the universe,” Camilo says.

What is in a galaxy?

Astronomers have noticed a problem when it comes to galaxies: although stars are formed in galaxies out of hydrogen, there doesn’t appear to be enough hydrogen to fuel their creation.

“How do these galaxies continue to form stars, where is the fuel coming from?” asks Camilo.

One idea is that galaxies recycle hydrogen (it explodes out during supernovae, but then gets sucked back in by gravity), but that these small amounts of hydrogen are difficult to detect. MeerKAT will be looking for them.

Search for dark matter

Dark matter is as mysterious as its name sounds: it makes up more than a quarter of the universe (much more than visible matter), but we can’t see it.

Some scientists think that dark matter forms a cosmic web, linking galaxies together. That said, this has not been directly detected.

“We expect to find more hydrogen near this web of dark matter,” says Camilo. And engineers and scientists have optimised MeerKAT to look for hydrogen.

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