NASA launches new telescope that could deliver cosmic eye candy
Two views of the “Pillars of Creation” of the Eagle Nebula, both taken by the Hubble Space Telescope. The left shows the pillars in visible light; the image on the right was taken in infrared light.
In December, NASA is expected to launch the massive $ 10 billion James Webb Space Telescope, which is sometimes touted as the successor to the aging Hubble Space Telescope.
The new telescope, the largest and most powerful ever put into space, will travel to an isolated location 1 million kilometers from Earth, where it can scan the far reaches of the universe.
After an installation period of approximately six months, NASA will unveil the first images of the telescope to the public.
“Will the Webb images be as beautiful as the Hubble images? Will we not only love them as having scientific value, but will they blow our minds? I’m pretty sure they are, ”says Jane Rigby, NASA astrophysicist with the James Webb team.
But the new telescope has some important differences that will affect the types of science it can do and the types of images that are sent home. Its main mirror is 21 feet in diameter and covered with gold, and it is much larger than the Hubble mirror. This will allow Webb to collect much more light and see galaxies much further away. The telescope will also make it easier to search for signs of life on Earth-sized planets in other solar systems by allowing scientists to analyze the tiny amount of starlight that filters through these planets’ atmospheres. .
A generation of iconic Hubble images
For three decades, the public has grown accustomed to space as seen through Hubble’s eyes. “I think Hubble is definitely the first telescope where the images appeared everywhere,” says Rigby. “I have socks with Hubble images on them. I saw them on the sides of a U-Haul coming down the freeway.
Hubble’s images, she says, strike us “in this awesome way, connected to everything, maybe in a spiritual way.”
It wasn’t always like that. After Hubble launched into orbit around Earth in 1990, the first images it sent back were surprisingly blurry. Her mirror turned out to have a little flaw, and this Hubble issue made the telescope a household name as late-night comedians and comics laughed at her poor vision.
A few years later, however, the astronauts installed corrective optics. And what Hubble saw then was mind-blowing. Robert Hurt, astronomer and visualization scientist at the California Institute of Technology / IPAC, remembers attending a science conference when some of Hubble’s first images were displayed. “It was like going to a rock concert,” says Hurt. “I mean, people were applauding.”
Large ground telescopes always had to look through Earth’s turbulent atmosphere, which distorts the light passing through it, Hurt says. The Hubble boom especially, in orbit, gave it crisp, incredibly detailed views. Familiar stars and clouds of gas suddenly transformed into magnificent luminous visions that were given names such as the “Pillars of Creation”. These heavenly scenes have become iconic.
Waiting for Webb infrared
While Hubble gazed at the stars and galaxies, astronomers and engineers worked hard on the James Webb Space Telescope, which is named after a former NASA administrator. Its development took much longer – and was much more expensive – than anyone expected.
The massive mirror of this telescope is divided into segments, so that it and a tennis court-sized five-layer sunshade can fold inside a rocket and later deploy. All of its technologies must work without a hitch, because unlike Hubble, there is no way to send a repair team.
It takes a long time for light to travel through space, and Webb will be able to capture the light that has traveled through most of the history of the universe. “Webb will be able to see galaxies as they were a few hundred million years after the Big Bang,” says Rigby.
The telescope can do this because it is optimized to see near and mid infrared light which is invisible to people. Hubble, on the other hand, primarily captures the type of optical light that human eyes can see.
An infrared telescope such as James Webb can not only see older, cooler objects, but it can also look through dust that can obscure stars and other objects in Hubble images.
“A lot of these iconic Hubble images are because you see dust scattering light all over the place, which is beautiful. But that makes it very difficult to study what’s inside, ”says Nikole Lewis, an astronomer at Cornell University.
Half science, half art
Deciding how to assign the colors our eyes can see to the different wavelengths of infrared light, she says, involves a bit of artistic license.
But there has also always been a certain amount of artistry in Hubble’s images. Hubble’s cameras return black and white images. Bright colors are added later – sometimes to mimic what our eyes can see and sometimes to highlight key scientific characteristics such as the presence of oxygen or other elements.
And even though Hubble is looking at the visible light spectrum, that doesn’t mean its sight is equal to what people would see. If you could get on a spaceship to a nebula, a cloud of dust and gas, and then look out the window, it wouldn’t look like a glorious picture of Hubble.
“You would see the slightest mist in the sky,” said Hurt. “It would be very dark. Because the total amount of light emitted by these nebulae is not very large and our eyes are very small.
He notes that Spitzer, another infrared space telescope that operated for about 17 years before shutting down in 2020, produced a lot of eye candy, despite being smaller and less powerful than James Webb. Spitzer was able to obtain images of the very center of the Milky Way galaxy, which is surrounded by dust particles that block the passage of visible light.
Lisa Storrie-Lombardi, director of the Las Cumbres Observatory and project manager for the Spitzer Space Telescope, expects James Webb to produce his own iconic images.
“The James Webb Space Telescope is a larger telescope than Spitzer or Hubble, and it’s going to take great infrared images,” she says. “They will be beautiful. “
She recalls that once, at the start of Spitzer’s mission, CNN posted one of the images from that infrared telescope and mistakenly called it a Hubble image.
“I knew Spitzer had really, you know, hit the nail on the head,” she laughs, because for the public, Hubble has long been the go-to for stunning images from space.
The world will soon see how James Webb’s images measure up. If the launch takes place at the end of the year, as planned, the first images should arrive by next summer, once the telescope is installed and set up and ready to do some science.
James Webb’s team have a top secret plan for which footage they’ll first show to the public, Rigby says. These images, she adds, “are meant to be breathtakingly beautiful, powerful, both visually and scientifically.”