The James Webb space telescope has only recently begun operations, astounding the globe and exceeding astronomers' expectations, but advancement continues: if all goes according to plan, humanity will have a new space telescope in a few decades that will make the Webb seem like a spyglass toy.
It will be the Stanford Gravity Telescope, an instrument so incredibly powerful that it will allow, for the first time in history, to see a planet in another solar system in detail. So much detail — on the scale of tens of kilometers per pixel — that astronomers say we can see continents, oceans, clouds, and even active volcanoes. In fact, they claim that we will be able to see how the atmosphere moves while the exoplanet rotates around its parent star.
How does it work
The project is one of three that has moved to phase 3 funding at NASA's Institute for Advanced Concepts, and its inventors recently published a new study in The Astrophysical Journal, offering new details on how they plan to make it happen. We already knew that this space telescope will not use conventional lenses but will exploit a phenomenon known as the Einstein Ring .
These rings can be seen around any massive object in space, from a star to a galaxy. The gravity created by the mass deforms the light that comes from very distant objects located behind it from the observer's point of view, amplifying it and creating a ring.
Using an algorithm, this ring can be put back together, transforming a distorted image into a normal image. James Webb, Hubble, and many ground-based observatories already use this effect with galaxies, revealing other galaxies so far away that we could not see with the direct use of today's mirrors and sensors.
The problem is that, in order to take advantage of the Einstein Ring that can 'generate' our sun, the telescope must be at a minimum distance of between 550 and 1,000 astronomical units (AU). Basically, the mission would seek to put the instrument 14 times the distance from the Sun to Pluto, enough to be able to investigate the thousands of planets that we know are in the range of 100 light years away.
Right now, Voyager 1 — the farthest man-made object from Earth — is at 156 AU after 44 years of travel. So the first problem will be to shorten the travel time. Right now the technology doesn't exist — such as direct fusion engines — to accelerate a telescope the size of Hubble to the rate of 20 AU per year, the minimum they consider acceptable.
So instead of sending a single telescope like Hubble or Webb, the team wants to send several small modular satellites toward the Sun, using their gravitational assist effect combined with solar sails to reach the point of observation in an acceptable time.
The constellation of modular mini-satellites — which to cut costs will be sent as cargo on other rocket flights — will be assembled in space autonomously, like Lego blocks. In this way, they say, we can have a mission ready to operate in just a decade from its launch. Once at its point of observation, the telescope would basically operate autonomously using artificial intelligence and following a preset list of targets. The reason for this autonomy is that, at the operating distance, communications between the telescope and Earth will take about 63 hours. To maneuver, the instrument could use ion engines during the ten years of the scientific mission.
Historical importance
It's an ingenious plan. Obviously, such a mission poses numerous challenges that have yet to be resolved. Like the James Webb, the plan to build this extraordinary machine has been a long time in the making and is still years away from being realized. In fact, some estimates give at least fifty years before we can execute it. Well over twenty that the Webb, which was unimaginable at the time, took time to go from fantasy to fantastic reality.
But these deadlines do not seem important on the historical scale. As Bruce Macintosh — one of the leaders of this project and professor of physics at the Stanford School of Humanities and Sciences and deputy director of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) — says, this new telescope has the potential to affect the very human consciousness, as did 'Earthrise', the first image of Earth sunrise over the moon taken by Apollo 8.
"We want to take pictures of planets orbiting other stars that are as good as the pictures we can take of planets in our own solar system. With this technology, we hope to take a picture of a planet 100 light-years away that has the same impact than the Apollo 8 image of Earth," says Macintosh. The image taken by the Apollo had a profound effect worldwide that influenced the creation of institutions such as the American Environmental Protection Agency or Doctors Without Borders.
We really don't know what effect seeing another habitable planet a hundred light years away from Earth will have. In the short term, maybe not much. But if we want to survive as a species — aside from not destroying ourselves as we seem to be constantly trying — we're going to have to have a very long-term plan.
Reference(s): Stanford Gravity Telescope, The Astrophysical Journal