Observing exoplanets directly is very difficult. If an alien being 100 light-years away from us wants to see Earth at a single pixel size, it will need a telescope with a primary lens of 90 kilometers in diameter. But there is a way to see the small exoplanets without the need for these impossible telescopes, and this method also provides the possibility of mapping their surfaces. The secret is to turn the sun into a giant lens.
Each object has mass that distorts spacetime, causing light to bend around it, and this creates the phenomenon known as gravitational lensing, which allows us to see beyond the object. And we can use our Sun, being the largest object around us, as a telescope lens to reach incredible magnifications for distant objects, and that’s how the Solar Gravitational Lens project began.
This mission may provide enough detail about the surface of an exoplanet so that we can see its continents and islands (and perhaps cities if they exist), but we have many challenges. For this system to work, the distance between the solar lens and the rest of the telescope must be 650 times the distance between the Earth and the sun. or 650 astronomical units (AU).
Requirements to turn the sun into a telescope at hand
Voyager One is the farthest man-made object from Earth, as it has been traveling for 45 years and is now 157 AU from the sun. The solar gravitational lens requires sending something four times further and in a much shorter time frame. A new paper shows that what is needed to make the mission work is on the ground, or that researchers are working on it now.
“We realized that most of the technologies needed to achieve the solar gravitational lensing project’s mission are either already in place or under active development,” said Dr. Slava Turishev of NASA’s Jet Propulsion Laboratory.
“This includes solar gliding, on-board power, and communications – all of which are now capable of supporting the mission with even more exciting capabilities coming soon,” he added.
The team aims to build a spacecraft with a small telescope that will travel this distance in less than 25 years, which means reaching a faster speed than any spacecraft we have launched towards the edge of the solar system. To succeed, the team plans to use a solar sail and bring the spacecraft close enough to the sun, which would then allow it to fly at high speed.
Ready to fly in 2034
This means that the target must be known in advance because the telescope will not be able to go to another planet and take a picture of it. The spacecraft must also be light because the solar sails require a very large surface area compared to the average mass. The team believes that the best solution is to use a satellite made of nanotechnology that can assemble to form a telescope in space.
“One of the most interesting challenges was to scale back some of the systems and instruments to fit the limits imposed by solar sailing. We need a small, efficient and inexpensive spacecraft,” explained Dr. Torichev.
The project is exciting and could have a major impact on the way humans study other worlds in the Milky Way and our search for extraterrestrial life. It may not take long to start it in the future if NASA decides to go ahead with it.
“We are ready to fly by 2034. This goal is ambitious, but it is feasible,” concluded Dr. Torichev.
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