Although manned space exploration to distant worlds is figuratively light-years away, our ability to glance across the heavens could be revolutionized with a technology that’s been right in front of our noses: the Sun.
Current technology has given us breathtaking imagery, but to detect what’s hiding in deep space, telescopes are very limited—often resolving “tiny fuzzy dots” representing exoplanets larger than Jupiter. To obtain high-quality images of exoplanets quickly, astronomers are hoping to use the Sun as a colossal telescopic lens.
The idea of this telescope, officially termed a “solar gravitational lens,” has been floating around for years , but a recent study has breathed new life into the subject. Using up-to-date modeling, a group of researchers thoroughly evaluated the feasibility of a solar telescope, modeling the Sun’s gravitational waves and demonstrating a proof-of-concept image of Earth (above). If their predictions are accurate, we may soon have the resolution to see distant planetary surfaces, greatly improving our potential to detect exoplanetary life.
Whether in a celestial telescope or your eye, all lenses perform a crucial, fundamental task: concentrate light from distant surroundings onto a small focal point. As the scientists illustrated in this video , the gravitational field of our sun doesn’t quite behave like a conventional lens. In addition to focusing light, the sun also gives off a tremendous amount of light, and could drown out important telescope information. To counteract this, scientist propose outfitting the scope with a carefully measured filter, blocking out the brightest parts of the sun to give distant exoplanet light a chance to be detected, concentrated, and ultimately focused.
Light isn’t the only problem: the sun’s gravity also bends and warps light around it, forming what scientists call an “Einstein ring,” named after the famed scientist who popularized the gravitational lens effect. The Einstein ring contains all the image information, and requires quite a bit of math to morph information back into a representative picture. However, by accumulating a series of Einstein ring-derived pixels, you could assemble them into a 1000×1000 pixel image. The resultant image would be unprecedented—what might be seen from a spaceship.
The study is giving this idea traction, but to work, the solar gravitational lens telescope requires a probe to travel a minimum of 550 astronomical units. That’s 600 times the distance of earth to the sun—further than any probes in existence. However, with technologies like e-sails , which harness solar wind to travel nearly 20 astronomical units per year, a functional solar scope seems within the grasp of our lifetime.
Image credit: DeLuca/Turyshev et al