Work to start on giant telescope to monitor solar winds
Work to assemble a giant new telescope on the grasslands of Inner Mongolia will start soon, according to researchers involved in the project.
Once complete, the Mingantu interplanetary scintillation (IPS) telescope will be the most sensitive of its kind in the world and play a key role in monitoring solar winds to help protect power grids on Earth as well as astronauts and satellites in space, according to the researchers.
Solar winds are continuous streams of charged particles blown out from the sun’s atmosphere. As they sweep through the solar system at speeds of hundreds of kilometres per second, they interact with the earth’s magnetic field. This is the cause of spectacular polar light shows, but the winds can also cause geomagnetic storms that disrupt communications and power supplies.
In February, a storm caused by solar winds knocked out 40 communications satellites launched by US company SpaceX as part of its Starlink project.
There are different ways to study the physics of solar winds, said radio astronomer Chen Linjie from the National Astronomical Observatories in Beijing, who is part of the Mingantu IPS telescope team. For instance, probes can be sent to examine the sun from close up, such as Nasa’s US$1.5 billion Parker Solar Probe, which has made the closest ever approach and is currently monitoring its upper atmosphere. Ground based telescopes can also play a role, however, and are less expensive.
The phenomenon they monitor is called interplanetary scintillation, which refers to the random fluctuations of radio signals from deep space as they travel through the solar wind towards earth.
“It’s similar to when you see twinkling stars in the night sky,” Chen said. “Your eyes receive optical waves that get scattered by the earth’s atmosphere. Our telescope receives radio waves that get scattered by the solar wind.”
By measuring the radio waves, scientists can reconstruct the 3D structure of the solar wind, including its velocity, density and other key parameters.
IPS telescopes have been built around the world since the 1970s, including in India, Japan and Mexico.
The new Mingantu telescope will have three rotatable cylindrical antennas – each 140 metres long and 40 metres wide – and will be able to observe thousands of radio sources when it starts operating next year, Chen said.
The 60 million yuan (HK$70.2 million) telescope – named after an 18th century Mongolian astronomer also known as Minggatu in his native language
– will also team up with two smaller ones nearby to form a triangular network to further increase observation accuracy.
The plan is to finish assembly by August and start aligning it in September.
“We have never built a cylindrical antenna this large before, so it’ll be a challenge,” Chen said.
The telescope is being built in a remote corner of the vast northern region on the edge of the Gobi Desert, about five to six hours’ drive north from Beijing. The site was chosen by astronomers about 15 years ago because it is sparsely populated and surrounded by mountains, which help block off radio interference.
“Radio noises have worsened a little bit since then, but it probably won’t affect our work since we observe at specific wavelengths,” he said.
Chen said the local government had also restricted radio transmissions in the area to better protect the telescopes.
The Mingantu IPS telescope project is part of the second phase of the Meridian Space Weather Monitoring Project, a plan sponsored by the government to build a network of dozens of monitoring sites across the country to better predict the weather in space.