NASA’s Webb Telescope to See Deeper Than Hubble to Edge of Universe

In addition to providing fresh insights into our own solar system, the new telescope—with its giant golden mirror and infrared eyes—will go beyond what Hubble can see and capture images of some of the very first stars and galaxies as they appeared more than 13.5 billion years ago, according to the National Aeronautics and Space Administration.

Seeing red

Hubble is NASA’s Energizer bunny, Dr. Windhorst said. In the 31 years since its launch in 1990, Hubble has taken more than 1.5 million photos, helped reveal that the universe is 13.8 billion years old and extended our understanding of how planets form.

But Hubble was designed to primarily capture visible light, which represents only a small sliver of the spectrum of light emitted by stars and other celestial objects. In contrast, Webb will capture a range of infrared light that is invisible to the human eye but that makes up much of the light that comes our way from the universe’s oldest and most distant galaxies.

The Hubble telescope

captures light from this

part of the electromagnetic

spectrum.

The Webb telescope is designed to see mostly infrared light.

The human eye can see wavelengths of light ranging from 380 to 700 nanometers, or billionths of a meter. Hubble sees in the 90- to 2,500-nanometer range, while Webb will see an even wider range of light wavelengths—from 600 to 28,500 nanometers.

Infrared cuts through clouds of gas and dust, allowing Webb to discover new stars and planets.

Mirror, mirror on the Webb

The bigger a telescope’s mirror, the more light it can collect and the more detailed the images it captures. Webb’s 21.5-foot-wide gold-coated mirror is nearly three times as large as Hubble’s. That means it can capture images in extraordinary detail. It could even show the face of Abraham Lincoln on a penny from a distance of 24 miles.

JAMES WEBB SPACE TELESCOPE

The Webb mirror has 6.25 times as much collecting area as the Hubble’s.

JAMES WEBB SPACE TELESCOPE

The Webb mirror has 6.25 times as much collecting area as the Hubble’s.

JAMES WEBB SPACE TELESCOPE

The Webb mirror has 6.25 times as much collecting area as the Hubble’s.

NASA wowed the world in 2004, when it released Hubble’s Ultra Deep Field, an extraordinary photograph of deep space showing galaxies as they appeared as many as 13 billion years ago, or within one billion years after the cosmic dawn.

This exposure displays 10,000 faint galaxies, including one barely visible red speck, shown below. This distant galaxy that Hubble caught a glimpse of dates back 13.4 billion years to 410 million years after the Big Bang. Dr. Windhorst likened Hubble’s ability to spot it to using the naked eye to seeing a firefly on the moon.

This red speck is

a distant galaxy

dating back 13.4

billion years

This red speck is

a distant galaxy

dating back 13.4

billion years

This red speck is

a distant galaxy

dating back 13.4

billion years

The combination of Webb’s infrared detectors and large mirror will allow it to home in on that red speck in much greater detail, along with many other specks in the sky.

The Hubble mission was to spend at least 15 years, until 2005, capturing images of the universe, but remains in operation despite a series of technical glitches that threatened to shut it down permanently as recently as July.

The Webb mission is expected to continue for five to 10 years, with NASA expecting the telescope to produce its first scientific photo this summer.

Write to Brian McGill at Brian.McGill@wsj.com