Weary in a time of the COVID-19, nothing feels more obscure than the future, as coronavirus updates scroll maddeningly by until the decision arises: to panic, or become one of the lucky ones, the post-blasé masters of distraction for a better tomorrow when, in the full clarity that comes only afterward, we resolve to look once more up to the universe and see who or what else survived catastrophes like ours. And, according to a new study, we may see signs of life on exoplanets with unimagined degrees of resolution.
'Solar gravity telescope' will magnify images of distant planets
More than 4,000 new planets were discovered beyond our solar system in the last twenty years — a testament to 21st-century astronomy — called exoplanets. We've learned a lot about them, but have only observed them as small ambiguous blips of data, such is the distance between us and them.
However, we may soon see oceans and continents on the surfaces of alien worlds — it's also not impossible for signs of life to show up. If it happens, it will be due to the Solar Gravity Lens (SGL) project — a proposal to send a telescope far away from the Sun, using its immense gravitational field to magnify the view of wildly distant planetary systems.
It's on the fringe of possible, but it's also very real.
"Solar Gravity Lens is a unique gift from nature that allows us to do direct high-resolution imaging of faint sources," said project leader Slava Turyshev of NASA's Jet Propulsion Laboratory, according to Forbes. "No other techniques allow us to do [this]. Classical instruments cannot compete."
NASA funds a telescope study in a league of its own
The idea behind SGL has been around for several years, but the team behind it finalized crucial details in a new study submitted to NASA this March. Turyshev and his colleagues were awarded up to $500,000 in funding as part of the NASA Institute for Advanced Concepts (NIAC) program to go forward with the study.
What distinguishes SGL from many other space telescopes is its use of a gravitational lens. Roughly a century ago, Albert Einstein wrote his theory of general relativity, according to which objects with mass in the cosmos produce a "dip" in their neighborhood — effectively a higher-dimensional curvature in the fabric of space-time — which changes the velocity of nearby objects. Even light itself.
Decades later, astronomers witnessed this effect in reality. Called an Einstein ring, they've seen light from a distant star or galaxy bend to the gravitational presence of another, closer galaxy — magnifying the image of the more distant object.
This effect helps us see galaxies too far to view, even with the most sophisticated telescopes. But we have new means — via the SGL theory — to use the Sun itself as a magnifying lens to see not just bright galaxies, but dimmer, modest planets, too.
This works because of the Sun's gravitational "focal length," according to which we wait until the Sun aligns opposite the satellite to a planet — up to 100 light-years away — and enjoy an unprecedented view of a planet's image magnified, even if the satellite were 548 times more distant from the Sun than the Earth (also called 548 astronomical units, or AU).
This is what the SGL mission might do, but for exoplanets. It would have to fly to a distant position carrying a one-meter telescope, said Turyshev to Forbes, but will allow us to see an Earth-sized planet roughly 100 light-years away with incredible resolution — good enough to parse significant features on the surface, even 10 kilometers wide.
"If you want to image an Earth that is 100 light-years from us with a classical telescope, the diameter of the telescope you must have is about 90 kilometers for just one pixel," said Turyshev, according to Forbes. "With SGL, you can make an image in a year with 200 to 300 pixels resolution."
Exoplanets without coronavirus under new resolution
In the new study, the team worked to analyze the potential resolution of the planet images viewed in such circumstances, and they are optimistic. "We can see that we are able to recover beautiful images of sources," said Turyshev, according to Forbes.
The primary mission plan will arrive at the focal point of the Sun in 25 years, after a launch in 2030. The space telescope — carried in a small spacecraft weighing only 100 kilograms at most — would be equipped with a large solar sail capable of achieving speeds of 25 AU per year.
Following this plan, the team claims the telescope could make the trip to interstellar space in only seven years. Once it has moved 548 AU from the Sun — 400 AU farther than NASA's Voyager 1 spacecraft and the most distant ever launched from Earth — the science mission will kick-off.
This attuned distance will allow the telescope to focus-in on distant targets. When the telescope lines itself up with the Sun and a distant planetary system, the Sun's gravitational magnifying lens will provide continual views of the distant system for years and years as it moves outwards, until it reaches a distance of roughly 2,500 AU (0.04 light-years) from the Sun.
While the coronavirus pandemic sweeps the world and reshapes the way we think of life on Earth, it's perhaps centering to remember that as we change, and grow, so too does life beyond our solar system. Perhaps one day, with gravitational lensing of the SGL space telescope, we'll see them, looking back at us, deeply concerned by the mess.