Sure A Not

Astronomers have discovered more than 5,000 planets outside of the solar system to date. The grand question is whether any of these planets are home to life. To find the answer, astronomers will likely need more powerful telescopes than exist today.

I am an astronomer who studies astrobiology and planets around distant stars. For the last seven years, I have been co-leading a team that is developing a new kind of space telescope that could collect a hundred times more light than the James Webb Space Telescope, the biggest space telescope ever built.

Almost all space telescopes, including Hubble and Webb, collect light using mirrors. Our proposed telescope, the Nautilus Space Observatory, would replace large, heavy mirrors with a novel, thin lens that is much lighter, cheaper and easier to produce than mirrored telescopes.

Because of these differences, it would be possible to launch many individual units into orbit and create a powerful network of telescopes.

The need for larger telescopes

Exoplanets – planets that orbit stars other than the Sun – are prime targets in the search for life. Astronomers need to use giant space telescopes that collect huge amounts of light to study these faint and faraway objects.

Existing telescopes can detect exoplanets as small as Earth. However, it takes a lot more sensitivity to begin to learn about the chemical composition of these planets. Even Webb is just barely powerful enough to search certain exoplanets for clues of life – namely gases in the atmosphere.

The James Webb Space Telescope cost more than US$8 billion and took over 20 years to build. The next flagship telescope is not expected to fly before 2045 and is estimated to cost $11 billion. These ambitious telescope projects are always expensive, laborious and produce a single powerful – but very specialized – observatory.

A new kind of telescope

In 2016, aerospace giant Northrop Grumman invited me and 14 other professors and NASA scientists – all experts on exoplanets and the search for extraterrestrial life – to Los Angeles to answer one question: What will exoplanet space telescopes look like in 50 years?

In our discussions, we realized that a major bottleneck preventing the construction of more powerful telescopes is the challenge of making larger mirrors and getting them into orbit. To bypass this bottleneck, a few of us came up with the idea of revisiting an old technology called diffractive lenses.

Conventional lenses use refraction to focus light. Refraction is when light changes direction as it passes from one medium to another – it is the reason light bends when it enters water. In contrast, diffraction is when light bends around corners and obstacles. A cleverly arranged pattern of steps and angles on a glass surface can form a diffractive lens.

The first such lenses were invented by the French scientist Augustin-Jean Fresnel in 1819 to provide lightweight lenses for lighthouses. Today, similar diffractive lenses can be found in many small-sized consumer optics – from camera lenses to virtual reality headsets.

Thin, simple diffractive lenses are notorious for their blurry images, so they have never been used in astronomical observatories. But if you could improve their clarity, using diffractive lenses instead of mirrors or refractive lenses would allow a space telescope to be much cheaper, lighter and larger.

A thin, high-resolution lens

After the meeting, I returned to the University of Arizona and decided to explore whether modern technology could produce diffractive lenses with better image quality. Lucky for me, Thomas Milster – one of the world’s leading experts on diffractive lens design – works in the building next to mine. We formed a team and got to work.

Over the following two years, our team invented a new type of diffractive lens that required new manufacturing technologies to etch a complex pattern of tiny grooves onto a piece of clear glass or plastic. The specific pattern and shape of the cuts focuses incoming light to a single point behind the lens.

The new design produces a near-perfect quality image, far better than previous diffractive lenses.

Because it is the surface texture of the lens that does the focusing, not the thickness, you can easily make the lens bigger while keeping it very thin and lightweight. Bigger lenses collect more light, and low weight means cheaper launches to orbit – both great traits for a space telescope.

In August 2018, our team produced the first prototype, a 2-inch (5-centimeter) diameter lens. Over the next five years, we further improved the image quality and increased the size. We are now completing a 10-inch (24-cm) diameter lens that will be more than 10 times lighter than a conventional refractive lens would be.

The power of diffraction

This new lens design makes it possible to rethink how a space telescope might be built. In 2019, our team published a concept called the Nautilus Space Observatory.

Using the new technology, our team thinks it is possible to build a 29.5-foot (8.5-meter) diameter lens that would be only about 0.2 inches (0.5 cm) thick. The lens and support structure of our new telescope could weigh around 1,100 pounds (500 kilograms).

This is more than three times lighter than a Webb-style mirror of a similar size and would be bigger than Webb’s 21-foot (6.5-meter) diameter mirror.

The lenses have other benefits, too.

First, they are much easier and quicker to fabricate than mirrors and can be made en masse. Second, lens-based telescopes work well even when not aligned perfectly, making these telescopes easier to assemble and fly in space than mirror-based telescopes, which require extremely precise alignment.

Finally, since a single Nautilus unit would be light and relatively cheap to produce, it would be possible to put dozens of them into orbit. Our current design is in fact not a single telescope, but a constellation of 35 individual telescope units.

Each individual telescope would be an independent, highly sensitive observatory able to collect more light than Webb. But the real power of Nautilus would come from turning all the individual telescopes toward a single target.

By combining data from all the units, Nautilus’ light-collecting power would equal a telescope nearly 10 times larger than Webb. With this powerful telescope, astronomers could search hundreds of exoplanets for atmospheric gases that may indicate extraterrestrial life.

Although the Nautilus Space Observatory is still a long way from launch, our team has made a lot of progress. We have shown that all aspects of the technology work in small-scale prototypes and are now focusing on building a 3.3-foot (1-meter) diameter lens.

Our next steps are to send a small version of the telescope to the edge of space on a high-altitude balloon. With that, we will be ready to propose a revolutionary new space telescope to NASA and, hopefully, be on the way to exploring hundreds of worlds for signatures of life.

Daniel Apai, Associate Dean for Research and Professor of Astronomy and Planetary Sciences, University of Arizona

Disclosure: Daniel Apai receives funding from NASA, NSF, and the Gordon and Betty Moore Foundation. He works for The University of Arizona.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Since the Lowy Institute’s first “Being Chinese in Australia: Public Opinion in Chinese Communities” survey was published in 2021, Australia’s relations with China have undergone significant upheaval. 

The Covid-19 pandemic, the rupture in Australia–China relations, the election of a Labor government and the turbulence in both countries accompanying their re-openings after their Covid-19 lockdowns have placed Chinese-Australian communities in the public spotlight.

Chinese-Australians and their association with Beijing have come under the microscope from the Australian government, media and the public — often in intensely political circumstances.

While the Labor government has eschewed megaphone diplomacy with China — an approach favored by the former Coalition government — certain parameters have been set for the way Australia views and engages with China.

Still, Chinese-Australians have welcomed the political re-engagement between Australia and China.

The “Being Chinese in Australia: Public Opinion in Chinese Communities” survey report released in April 2023 shows that 37% of Chinese-Australians think Australia-China relations will be a “critical threat” to Australia’s vital interests in the next 10 years – a 14% drop since 2021.

The greater sense of optimism about Australia-China relations coincides with more positive feelings towards Australia in general. For example, 92% of Chinese-Australians say Australia is a “good” or “very good” place to live in the 2023 survey.

Chinese-Australians trust Australia most to act responsibly in the world, reinforcing their growing connections to Australia. Meanwhile, their sense of belonging to China and the Chinese people has declined, dovetailing with a drop in trust in China. Now less than half of the Chinese-Australian population has confidence in China’s President Xi Jinping.

Intense debates about China are now mainstream in Australian politics and this has placed Chinese-Australians in an uncomfortable position.

News headlines warning about the prospect of war do not align neatly with Chinese-Australians’ threat perception. Six out of ten Chinese-Australians say China is unlikely to be a military threat to Australia in the next 20 years.

Seven in ten Chinese-Australians believe Australia should remain neutral in the event of a military conflict between China and the United States – a view shared by only half of the Australian population. 

Yet there are differences within the Chinese-Australian communities. Of those born in mainland China, 73% say Australia should remain neutral compared to 65% of those born in Australia and 61% of those born in Hong Kong.

But the headlines and aggressive political rhetoric about China homogenizes and reinforces public perceptions about China and inadvertently, Chinese-Australians.

The political rhetoric about China has changed under the Labor government. But more work needs to be done to create a cohesive Australian society in the face of persistent discrimination and negative portrayals of China and ethnic Chinese in the media.

The evolution of the Australia-China debate and its impact on Chinese-Australian communities show that foreign and defense policies and national security should not be treated as separable from domestic politics. Public discussions about such policies have a quantifiable impact on a large proportion of Australia’s population.

How Australia should navigate the intersection of national security and social cohesion with China is uncertain. Increasing cultural and linguistic diversity among Australia’s national security and intelligence community could help.

Australia’s Chinese diaspora and their bicultural skills should be channeled as an asset into helping navigate the Australia-China relationship.

Workforce diversification is not a new argument and some will contend that it will not change Australia’s basic orientation when it comes to national security. But from a technical expertise perspective, Australia’s intelligence community is lacking cultural and linguistic diversity. 

Government departments involved in managing Australia-China relations appear to be ill-equipped for the strategic moment when only 1.2% and 1.7% of Department of Foreign Affairs and Trade staff and the defense workforce respectively are proficient in Mandarin.

Diversity in key intelligence institutions creates “a synergy of different perspectives” to address complex issues that can increase the array of policy options available to governments. Australia could start seeing Chinese politics in a more nuanced way rather than as a pyramid where President Xi sits on top. 

There is a lot of policy entrepreneurialism at the local level in Chinese politics and local officials often conduct government affairs that subvert the complete control of the Chinese Communist Party.

Perhaps those who make calculations about China’s role in Australia’s region will see that a myriad of interests shape China – and that a one-size-fits-all policy does not suffice when managing Australia-China relations – if they accept that China is more complex than Xi and the Chinese Communist Party. 

Greater cultural and linguistic diversity in government will ultimately shape how Australia sees Chinese-Australian communities too. They are pluralistic and diverse with skills that can benefit the nation.

The lack of diversity across key Australian public and international facing institutions presents huge obstacles when addressing the complex nature of Australia’s relationship with China, let alone with the world.

Jennifer Hsu is Visiting Senior Fellow at the Social Policy Research Centre, UNSW and is the author of Being Chinese in Australia: Public Opinion in Chinese Communities and was previously the Project Director of the Multiculturalism, Identity and Influence Project at the Lowy Institute.

This article was originally published by East Asia Forum and is republished under a Creative Commons license.

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