Asia can be leader in future world astronomy projects, says EAO Chief

Vishwam Sankaran

New Delhi, Feb 5 (PTI) Asia can play a leadership role in mega astronomy projects like the one that captured the first-ever image of a black hole, according to Paul Ho, Director General of East Asian Observatory (EAO).

The breakthrough image of the black hole captured last year by the Event Horizon Telescope (EHT) was based on a technique for imaging far-away cosmic objects, known as Very Long Baseline Interferometry (VLBI).

A study, published in the journal Nature Astronomy in 2018, said the VLBI technique offers resolution superior to any other astronomical instrument at other wavelengths.

This enables high-precision imaging of cosmic sources of radio waves such as black holes, stars, gas and dust clouds.

In this technique, the observations made by individual telescopes separated by very large distances are combined, mimicking a single large telescope with a size equal to the maximum separation between each of them, the study explained.

'Years ago, we thought we would have to build a very large space telescope to image a black hole,' Paul Hertz, director of the astrophysics division at NASA Headquarters in the US, had said post the breakthrough announcement.

'By getting radio telescopes around the world to work in concert like one instrument, the EHT team achieved this, decades ahead of time,' Hertz said.

According to Ho, if scientists have to study, for instance, the supermassive black hole at the centre of the Milky Way galaxy, which is 1000 times bigger, and 1000 times farther than the one whose image was developed last year, more telescopes are needed to be a part of the VLBI approach.

Ho was speaking at the Vigyan Samagam, a 'Mega Science Exhibition' held here last month.

He added that eight telescopes participated in the experiment to form the first-ever image of a black hole, and these telescopes were distributed all over the Earth.

Ho noted Asia is working on four more radio-telescopes, with the continent's participation in astronomy already significant.

'The way Asia can dominate the field is to contribute to building a very large network of telescopes which act together to makeup a single large telescope the size of the Earth,' he said.

He said building a radio-telescope in the Tibetian mountains to be part of a VLBI network with those in Greenland, Japan, Korea, and Hawaii can be a strategic upgrade in the approach.

'In the Tibet highlands, there is very high elevations. For astronomy, it is very important to get up above water as much as possible,' Ho told PTI.

'For optical wavelength astronomy, we don't have to be that high. But what we are dealing with is millimetre wavelengths, for which we need to be as high as possible above the water,' he explained.

According to Ho, deploying radio-telescopes in very high altitudes can help conduct better astronomy using the VLBI approach. The EAO chief said the Himalayas is one of the spots on the Earth that has very good conditions for deploying radio telescopes.

'The reason why I suggest Himalayas is because from there we cannot see the big telescope in Chile, and we do not have mutual visibility,' the astronomer said.

'So that means that if you put a telescope in the Himalayas, we can have mutual visibility with some of the other telescopes in the VLBI network, and therefore establish an independent network. And that will be useful in terms of Asian astronomy,' he explained.

According to the astronomer, the improvement in resolution brought about by new telescopes depends on how far apart as possible it can be from the others.

'For that, I suggest Tibet as a location because it is very far off compared to Hawaii and Greenland. That particular triangle spans the Earth, and that's why it is interesting,' he explained.

'We want the most separated telescopes in order to achieve the highest resolution. Putting them close to each other, or next to each other is not as useful,' Ho added.

The next generation of experiments will have all sorts of resolution improvement in terms of time, energy, and motion, and Asia is expected to play a leading role, the scientist said.

He proposed that China, Japan, and India invest and work together, and compete with the West since all the mega astronomy projects are following the treaty organisations of the West.

'So this tells us that a whole lot more could be done. We need to form the Asian Treaty Organisation,' he said.

According to Ho, Asia, with its time, resources, workforce, and technology, can lead new astronomy mega projects into the future.

'When we do this together, we can develop and control the technology to the next stage,' he said. PTI VIS SAR SAR