The first image from NASA‘s James Webb Space Telescope, the highest-resolution infrared view of the universe ever seen, was released. On Monday, US President Joe Biden revealed the first colour photograph.

Also read: All you need to know about James Webb Space Telescope

But how do its images compare to those of Hubble?

In April 1990, the Hubble Space Telescope was launched into low-Earth orbit. The famed observatory has enlarged our vision of the cosmos and captured our interest with the breathtaking photographs it has collected over the last three decades. What was previously a faint and unfathomable void became a detailed and colourful universe, with stars and galaxies seen like never before.

According to a NASA fact sheet, the James Webb Space Telescope, with its huge gold mirror and infrared light observation equipment, is meant to “see” things 10 to 100 times fainter than what Hubble can see.

According to the document, the photographs Webb catches “will be detailed and spectacular.”

It is not a replacement telescope

Webb is frequently referred to as Hubble’s replacement or successor. Despite a few hiccups over the years, Hubble’s science instruments are still operational, and the two large telescopes are prepared to observe together (although far apart) in orbit.

Hubble is quite close to us in low Earth orbit, but Webb will fly considerably further, to the Sun-Earth Lagrange point 2 (L2), a gravitationally stable position 930,000 miles (1.5 million kilometres) from Earth.

Also read: NASA reveals first image from James Webb Space Telescope: See here

Furthermore, while both Hubble and Webb are enormous space telescopes (albeit Webb is somewhat larger), they “see” the cosmos in fundamentally different ways.

“It will take amazing images; they will be better than what Hubble did,” Klaus Pontoppidan, project scientist for the Webb Space Telescope at the Space Telescope Science Institute in Baltimore, stated during a news briefing in May. However, while Webb’s photographs will be superior in some ways, they will also be fundamentally “different” because of the differing wavelengths, according to Pontoppidan.

While Hubble typically studies light at optical and ultraviolet wavelengths, Webb is developed to detect light at infrared wavelengths.

Infrared images

Webb will catch stunning photographs by observing in infrared.

“It will look very, very different than Hubble,” Pontoppidan stated. “The stars themselves fade away they get fainter and fainter [when you] go to [a] longer wavelength, but interstellar clouds go brighter and brighter and brighter.”

As you move into the infrared light region of the spectrum, some gas and dust features become wispy, Pontoppidan explained. But this isn’t always a terrible thing.

Also read: Who was James Webb?

“I think maybe there was some concern that, you know, you don’t want images that end up looking wispy,” Pontoppidan expalined. “But as it turns out, actually, if you just go a little bit further out into infrared … the dust itself lights up in thermal light. You get a nebula that shines.”

Infrared Differences

According to the fact sheet, Hubble can see light with wavelengths ranging from around 200 nanometers (nm) to 2.4 microns, but Webb’s range will be from about 600 nm to 28 microns. Visible light extends from roughly 700 to 400 nm.

Webb will be able to view the red/orange region of the visible light spectrum even though it predominantly observes infrared light. The gold coating on its mirrors captures blue light from the visible spectrum while reflecting yellow and red visible light.

Although it is not Hubble’s principal observation function, it does have the ability to monitor some infrared, thus this type of observation is not entirely unexpected. In fact, to commemorate the space telescope’s 22nd anniversary, the Hubble team produced a spectacular infrared image of the Horsehead Nebula in 2013.

The potential of infrared

Hubble has been providing magnificent photos to the world for decades and has similar sharpness to Webb. “Webb’s angular resolution, or sharpness of vision, will be the same as Hubble’s,” the fact sheet stated, adding, “Webb images will appear just as sharp as Hubble’s do.” Webb’s resolution, according to NASA, would allow it to discern details of an object the size of a US coin 24 miles (40 km) away.

Despite this resemblance, Webb has a significantly larger mirror — 21.3 feet (6.5 metres) wide vs 7.8 feet (2.4 metres) — cutting-edge detectors, and is meant to see further into the infrared spectrum than Hubble.

Webb’s infrared observations will allow astronomers to look considerably further into the universe, according to NASA. Its larger mirror also provides more surface area for light collection, allowing the scope to peek even far out into space, allowing astronomers to look “back in time” at the universe billions of years ago.

Webb was created with the goal of being able to “see” the first stars and galaxies that formed in the early universe. It can identify things that are 10 billion times fainter than the brightest stars seen without a telescope, or 10 to 100 times fainter than what Hubble can see.

Webb has four scientific equipment to aid it in its observations. The Near Infrared Camera (NIRCam), Near-Infrared Spectrograph (NIRSpec), Mid-Infrared Instrument (MIRI), and Fine Guidance Sensor/Near Infrared Imager and Slitless Spectrograph (FGS-NIRISS) are among them.

Webb “can do what we call imaging spectroscopy,” Pontoppidan explained, “where it can take an image, but it will take a spectrum and every pixel of the image as well.” There is information about the spectrum of wavelengths present in each tiny component of the image in imaging spectroscopy. This can assist scientists figure out what components or molecules generated the spectrum.

Pontoppidan added that Webb’s unique suite of imaging tools will enable it to perform a wide range of other scientific tasks, such as observing exoplanets transiting in front of stars or determining the composition of a cloud in a star-forming region; he cited studies that may look for ice, water, and complex organics in exoplanet atmospheres.

NASA, the European Space Agency, and the Canadian Space Agency collaborated on the James Webb Space Telescope.