• Wed. Dec 6th, 2023

An array of mini-telescopes could outsmart the web’s ability to hunt for habitable worlds

An array of mini-telescopes could outsmart the web’s ability to hunt for habitable worlds

Astronomers have discovered more 5,000 planets outside the solar system Date. That is the big question Any of these planets is home to life. To find the answer, astronomers will need to More powerful telescopes than exists today.

I am a An astronomer who studies astronomy and planets around distant stars. For the past seven years, I’ve been collecting a hundred times more light than leading a team developing a new type of space telescope. James Webb Space TelescopeThe largest space telescope ever built.

Almost all space telescopes, including Hubble and Webb, use mirrors to collect light. Our proposed telescope, the Nautilus Space Observatory, much lighter, cheaper, and easier to build than mirrored telescopes, a novel, thinner lens would replace large, heavy mirrors. Because of these differences, many individual units can be launched into orbit and create a powerful network of telescopes.

Exoplanets like TOI-700d, shown in this artist’s rendering, are planets beyond our solar system that are prime candidates in the search for life.

NASA’s Goddard Space Flight Center

The need for larger telescopes

Exoplanets – planets orbiting stars other than the Sun – are prime targets in the search for life. Astronomers have to use giant space telescopes, which collect large amounts of light Study these dim and distant objects.

Existing telescopes can detect Earth-sized planets. However, more sensitivity is needed to begin studying the chemical composition of these planets. Even the web is powerful enough to search Some exoplanets for signs of life – that is, Gases in the atmosphere.

More than the cost of the James Webb Space Telescope It cost US$8 billion and took more than 20 years to build. The next flagship telescope is not expected to fly before 2045 11 billion dollar cost. These ambitious telescope projects are always expensive and laborious, and require the construction of a powerful – but highly specialized – observatory.

A new type of telescope

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

In our discussions, we learned that a major obstacle preventing the construction of more powerful telescopes is the challenge of making large mirrors and getting them into orbit. To overcome this obstacle, 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 This is how light bends when it passes from one medium to another – entering water. Diffraction, on the other hand, is the bending of light at angles and obstacles. A cleverly arranged pattern of steps and cones on a glass surface will form a diffractive lens.

Such lenses were first invented in 1819 by the French scientist Augustin-Jean Fresnel. Lighthouses. Today, similar diffractive lenses can be found in many small-sized consumer optics – from Camera lenses until Virtual reality headsets.

Thin and simple diffractive lenses Notorious for their blurry pictures, so they are not used in astronomical observatories. But if you can improve their clarity, using diffractive lenses instead of mirrors or refractive lenses can make a space telescope much cheaper, lighter and larger.

One advantage of diffractive lenses is that they continue to get thinner as the diameter increases.

Daniel Apay/University of Arizona

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 me Thomas Milster – one of the world’s leading experts in diffractive lens design – works in the building next door to mine. We formed a team and got to work.

Over the next two years, our team invented a new type of diffractive lens that required new manufacturing techniques to etch a complex pattern of tiny grooves on clear glass or plastic. The special pattern and shape of the cuts focus the incoming light to a single point behind the lens. The new design is produced by A Almost perfect picture qualityMuch better than previous diffractive lenses.

A diffractive lens bends light using etchings and patterns on its surface.

Daniel Apay/University of Arizona

Focusing is done by the surface structure of the lens, not the thickness, and you can easily enlarge the lens. It keeps it very thin and light. Bigger lenses gather more light, lighter means Inexpensive launches into orbit – Two outstanding characteristics of a space telescope.

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

The power of a diffraction space telescope

This new lens design makes it possible to rethink how a space telescope is built. In 2019, we published a concept called Our Team Nautilus Space Observatory.

Using the new technology, our team thinks it’s possible to make a 29.5-foot (8.5-meter) diameter lens that’s only about 0.2 inches (0.5 centimeters) thick. Our new telescope’s lens and support structure will weigh about 1,100 pounds (500 kilograms). It would be three times lighter than a similarly sized Webb-style mirror and larger than Webb’s 21-foot (6.5 m) diameter mirror.

The thin lens allowed the team to design a lighter and cheaper telescope, which they named the Nautilus Space Observatory.

Daniel Apay/University of Arizona

Lenses have other advantages. First of all, they Very easy and fast to forge rather than mirrors Can also be made in batches. Second, lens-based telescopes work well even if they are not perfectly aligned, making these telescopes easier to use. add up fly in space than mirror-based telescopes, which require much more precise alignment.

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

Each individual telescope would be an independent, highly sensitive observatory capable of collecting more light than the web. But the real power of the Nautilus comes from turning all the individual telescopes on a single target.

By combining the data from all the units, Nautilus’ light-gathering power would be equivalent to a telescope ten times the size of Webb’s. With this powerful telescope, astronomers can search hundreds of exoplanets for atmospheric gases. Refers to extraterrestrials.

Although the Nautilus Space Observatory is still far from launch, our team has made a lot of progress. We have shown all aspects of the technology working 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 smaller version of the telescope to the edge of space in a high-altitude balloon.

With that, we’ll be ready to propose a revolutionary new space telescope to NASA, and hopefully on its way to exploring hundreds of worlds for signatures of life.

This article was originally published the conversation By Daniel Apay of the University of Arizona. Read Original article here.

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