October 20, 2021

I, Science

The science magazine of Imperial College

Executive Officer of the ALMA telescope Paulina Bocaz explains how it will help unravel how stars form ...


Why is ALMA located in Chile?

“The sky in the Atacama Desert is so clean, because of the lack of moisture and light pollution, that when you see the sky you are able to distinguish [it] as a relief and not simply in two dimensions as in other places.”

What does this observatory aim to discover?

“ALMA will try to better understand star and planet formation and will be able to get close to the Big Bang as well. But also we are expecting to make unforeseen discoveries and that is really exciting. This is a powerful instrument pointing upwards.”
Indeed, ALMA has already made important discoveries such as the observation of fertile star factories in the infant universe, 12.8 billion years ago; the first detection of star formation close to the supermassive black hole at the centre of the Milky Way; and the presence of sugar molecules (glycolaldehyde) in the gas surrounding a young, Sun-like star. One-tenth of ALMA’s time is reserved for astronomers working in Chilean institutions with the remaining 90% available to the rest of the world.

ALMA is located on the Chajnantor plateau, very close to the San Pedro de Atacama and Toconao indigenous communities. Some days before ALMA’s inauguration, the observatory held an activity with these local communities – how was that?

“We went to make a payment [an offering of coca leaves, among other symbols] at 5,000 metres above sea level. Members of the community thank the Mother Earth and ask both for the community welfare and for the observatory’s success. That was a great honour for us and a signal of respect [to the indigenous community].”

And what about the UK’s participation in ALMA? The ’Front End‘ is the first element in a complex chain of signal receiving, conversion, processing and recording of this observatory. This system is designed to receive signals from ten different frequency bands, from 0.3 mm (band 10) to 9.6 mm (band 1). To coordinate this massive task, ALMA created three Front End Integration Centres: one in the USA, another in Taiwan and the third in the UK, located at the Rutherford Appleton Laboratory.
Bocaz explained that this latter laboratory delivered the last 26 units to Chile at the beginning of this year, completing the 70 receivers that ALMA needs to work, just in time for the inauguration.