James Webb Telescope

Background

Heralded as a time machine able to reveal the secrets of the cosmos, the $10B James Webb Space Telescope is humanity's strongest tool yet to capture light from the earliest observable moments of the universe (see visual 101).

Launched by NASA in 2021, images from the 14,000-pound Webb have transformed theories of star formation, black holes, and more—while revealing jaw-dropping shots of the cosmos and inspiring a new generation of space fans. 

Discoveries

The telescope's discoveries have come at a rapid clip since it began science operations in the summer of 2022. Its sophisticated array of infrared tools has revealed: 

• well-established and luminous galaxies as early as 500 million years after the Big Bang, much earlier than previously believed.

• vivid shots of 50 young stars in early development in the nearby, previously opaque Rho Ophiuchi cloud complex.

• nearly 50 pairs of Jupiter-sized planets orbiting each other within the Orion Nebula, a totally new category of celestial object called a JuMBO.

• ancient starlight from a quasar, one of the oldest galaxies hosting a supermassive black hole the size of 1.4 billion suns. 

Peering Into the Past 

It's easy for stargazers to forget that thstarlight we see with our naked eyes is, in fact, incredibly old, showing us the literal past. 

Even though light travels at great speed—186,000 miles per second—the vast distances it spans means it shows up to an observer long after it was first emitted from an object (watch visualization). The light from our sun, for example, takes eight minutes to travel to Earth.

The Webb telescope has been optimized to collect the most distant light detectable, enabling it to see close to 13.5 billion years into the past—roughly 3 billion more than the Hubble telescope, its predecessor.

Telescope Tech

Space-based telescopes have the advantage of bypassing Earth's dense, light-filtering atmosphere. The Webb is in solar orbit roughly 1 million miles from the Earth at a point known as Lagrange 2, a stable position where the relative gravitational pulls of the Earth and the sun cancel each other out.

At 21 feet across, the Webb's famously honeycomb-shaped observing surface is six times larger than the Hubble's, constructed of 18 hexagonal gold-plated beryllium mirrors. 

While the Hubble collected data on the visible and ultraviolet light segments of the electromagnetic spectrum, Webb is equipped with several tools sensitive to mid- to low-infrared wavelengths, enabling it to see through visible light-blocking cosmic dust.

For the Webb to retain sensitivity to lower infrared wavelengths, it has to remain at extremely low temperatures (close to -400 degrees Fahrenheit). To that end, a tennis court-sized sunshield keeps the Webb's instruments in permanent shadow. 

Goals

The Webb surpassed expectations well before its initial five-year mission concluded; it's expected to remain functional for up to 20 years. Learn more about the Webb's mission and the man behind the telescope's name here.