Astronomers have found greater than 5,000 planets exterior of the photo voltaic system so far. The grand query is whether or not any of those planets are residence to life. To discover the reply, astronomers will seemingly want extra highly effective telescopes than exist at this time.
I’m an astronomer who research astrobiology and planets round distant stars. For the final seven years, I’ve been co-leading a crew that’s growing a brand new form of area telescope that would acquire 100 instances extra mild than the James Webb Space Telescope, the largest area telescope ever constructed.
Almost all area telescopes, together with Hubble and Webb, acquire mild utilizing mirrors. Our proposed telescope, the Nautilus Space Observatory, would change giant, heavy mirrors with a novel, skinny lens that’s a lot lighter, cheaper, and simpler to provide than mirrored telescopes. Because of those variations, it will be potential to launch many particular person models into orbit and create a robust community of telescopes.
The Need for Larger Telescopes
Exoplanets—planets that orbit stars apart from the solar—are prime targets within the seek for life. Astronomers want to make use of big area telescopes that acquire big quantities of sunshine to examine these faint and faraway objects.
Existing telescopes can detect exoplanets as small as Earth. However, it takes much more sensitivity to start to be taught in regards to the chemical composition of those planets. Even the James Webb Space Telescope is simply barely highly effective sufficient to go looking sure exoplanets for clues of life—particularly gases within the environment.
Webb price greater than $8 billion and took over 20 years to construct. The subsequent flagship telescope isn’t anticipated to fly earlier than 2045 and is estimated to price $11 billion. These formidable telescope tasks are all the time costly, laborious, and produce a single highly effective—however very specialised—observatory.
A New Kind of Telescope
In 2016, aerospace big Northrop Grumman invited me and 14 different professors and NASA scientists—all consultants on exoplanets and the seek for extraterrestrial life—to Los Angeles to reply one query: What will exoplanet area telescopes appear to be in 50 years?
In our discussions, we realized {that a} main bottleneck stopping the development of extra highly effective telescopes is the problem of constructing bigger mirrors and getting them into orbit. To bypass this bottleneck, a couple of of us got here up with the thought of revisiting an outdated expertise known as diffractive lenses.
Conventional lenses use refraction to focus mild. Refraction is when mild adjustments course because it passes from one medium to a different—it’s the cause mild bends when it enters water. In distinction, diffraction is when mild bends round corners and obstacles. A cleverly organized sample of steps and angles on a glass floor can type a diffractive lens.
The first such lenses had been invented by the French scientist Augustin-Jean Fresnel in 1819 to offer light-weight lenses for lighthouses. Today, related diffractive lenses will be discovered in lots of small-sized shopper optics, from digicam lenses to digital actuality headsets.
Thin, easy diffractive lenses are notorious for his or her blurry photographs, so that they have by no means been utilized in astronomical observatories. But when you may enhance their readability, utilizing diffractive lenses as an alternative of mirrors or refractive lenses would enable an area telescope to be less expensive, lighter, and bigger.
A Thin, High-Resolution Lens
After the assembly, I returned to the University of Arizona and determined to discover whether or not trendy expertise may produce diffractive lenses with higher picture high quality. Lucky for me, Thomas Milster—one of many world’s main consultants on diffractive lens design—works within the constructing subsequent to mine. We fashioned a crew and set to work.
Over the next two years, our crew invented a brand new sort of diffractive lens that required new manufacturing applied sciences to etch a fancy sample of tiny grooves onto a bit of clear glass or plastic. The particular sample and form of the cuts focuses incoming mild to a single level behind the lens. The new design produces a near-perfect high quality picture, much better than earlier diffractive lenses.
Because it’s the floor texture of the lens that does the focusing, not the thickness, you’ll be able to simply make the lens greater whereas protecting it very skinny and light-weight. Bigger lenses acquire extra mild, and low weight means cheaper launches to orbit—each nice traits for an area telescope.
In August 2018, our crew produced the primary prototype, a two-inch (five-centimeter) diameter lens. Over the subsequent 5 years, we additional improved the picture high quality and elevated the dimensions. We are actually finishing a 10-inch (24-cm) diameter lens that shall be greater than 10 instances lighter than a standard refractive lens could be.
Power of a Diffraction Space Telescope
This new lens design makes it potential to rethink how an area telescope may be constructed. In 2019, our crew printed an idea known as the Nautilus Space Observatory.
Using the brand new expertise, our crew thinks it’s potential to construct a 29.5-foot (8.5-meter) diameter lens that may be solely about 0.2 inches (0.5 cm) thick. The lens and assist construction of our new telescope may weigh round 1,100 kilos (500 kilograms). This is greater than 3 times lighter than a Webb–model mirror of the same dimension and could be greater than Webb’s 21-foot (6.5-meter) diameter mirror.
The lenses produce other advantages, too. First, they’re a lot simpler and faster to manufacture than mirrors and will be made en masse. Second, lens-based telescopes work properly even when not aligned completely, making these telescopes simpler to assemble and fly in area than mirror-based telescopes, which require extraordinarily exact alignment.
Finally, since a single Nautilus unit could be mild and comparatively low cost to provide, it will be potential to place dozens of them into orbit. Our present design is the truth is not a single telescope, however a constellation of 35 particular person telescope models.
Each particular person telescope could be an unbiased, extremely delicate observatory in a position to acquire extra mild than Webb. But the actual energy of Nautilus would come from turning all the person telescopes towards a single goal.
By combining knowledge from all of the models, Nautilus’ light-collecting energy would equal a telescope practically 10 instances bigger than Webb. With this highly effective telescope, astronomers may search tons of of exoplanets for atmospheric gases that will point out extraterrestrial life.
Although the Nautilus Space Observatory remains to be a good distance from launch, our crew has made plenty of progress. We have proven that each one elements of the expertise work in small-scale prototypes and are actually specializing in constructing a 3.3-foot (1-meter) diameter lens. Our subsequent steps are to ship a small model of the telescope to the sting of area on a high-altitude balloon.
With that, we shall be able to suggest a revolutionary new area telescope to NASA and, hopefully, be on the way in which to exploring tons of of worlds for signatures of life.
This article is republished from The Conversation below a Creative Commons license. Read the authentic article.
Image Credit: Katie Yung, Daniel Apai/University of Arizona and AllThingsSpace /SketchFab, CC BY-ND. A light-weight, low cost area telescope design would make it potential to place many particular person models in area directly.