Thread by @NBCNews

INTERACTIVE: This gold-plated, alien-hunting space telescope is about to begin a journey that could reveal some of the universe's most enduring mysteries and take us billions of years back in time.

Here's how it'll work and why it’s so significant →

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The James Webb Space Telescope is being billed as the successor to the Hubble Telescope, and it comes with huge technological advances.

NASA is describing this as an "Apollo moment."

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Because it takes time for light to travel through space, telescopes essentially function as time machines by capturing events that happened billions of years ago.

The Webb telescope will be able to see farther than ever — and farther back in time.

About 13 billion years.

You might be familiar with these images of cosmic gas and dust (thank you, Hubble Telescope).

They are big and awe-inspiring — and they're also blocking our view.

The Webb Telescope will use infrared technology to observe the celestial objects beyond.

And what about aliens? The Webb telescope will be keeping an eye out.

It has instruments sensitive enough to sniff out the atmospheres of exoplanets — including possibly faint biosignatures of extraterrestrial life.

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How will it work?

The telescope’s huge primary mirror, which collects light from celestial objects, is key (the larger the mirror, the more detail it can pick up.)

It's honeycomb-shaped mirror measures about 270 sq. ft and is made up of 18 gold-coated segments.

The Webb observatory will be able to see a long way but it can't do its work from Earth.

It will launch on Dec. 24, beginning a million-mile journey to an orbit far enough from the sun to do its careful work.

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Once it’s in place, the Webb Telescope will undergo an intricate, monthlong unfurling process that @NASA has nicknamed "29 days on the edge."

After six months, it will snap its first images.

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