James Webb Space Telescope
Webb’s First Deep Field — galaxy cluster SMACS 0723, 4.6 billion light-years away. This patch of sky is roughly the size of a grain of sand held at arm’s length. Every smear of light is an entire galaxy.
Gallery
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Key images
Pillars of Creation — Eagle Nebula, 6,500 ly
JWST revisited the 1995 Hubble image in near-infrared, peering through the gas and dust to reveal thousands of previously hidden forming stars. The tallest pillar stands about 4 light-years high. The baby stars visible in the NIRCam image are between 100,000 and a few million years old — infants, in stellar terms.
Stephan’s Quintet — compact galaxy group, 290 Mly
The largest image released at JWST’s first unveiling: 150 million pixels from nearly 1,000 separate files. Four of the five galaxies are gravitationally bound and slowly merging. NGC 7318b is actively crashing into the group at 800 km/s, generating a shockwave larger than the Milky Way.
Carina Nebula “Cosmic Cliffs” — 7,600 ly
What looks like a mountain range at sunset is actually the edge of a gaseous cavity within NGC 3324, carved by ultraviolet radiation and stellar winds from young massive stars just off the top of the frame. The “mountains” are 7 light-years tall.
Southern Ring Nebula — planetary nebula, 2,500 ly
Two stars at the center: one dying (throwing off shells of gas), one already dead (a white dwarf). JWST revealed for the first time that the inner star is coated in dust — solving a decades-old mystery about how dying stars seed the interstellar medium with heavy elements.
Tarantula Nebula — Large Magellanic Cloud, 161,000 ly
The most active star-forming region in the local group. JWST reveals tens of thousands of young stars that were previously hidden behind dust. The brilliant central cluster, R136, contains some of the most massive stars known — up to 150 solar masses.
JWST vs Hubble
| Property | Hubble | JWST |
|---|---|---|
| Mirror diameter | 2.4 m | 6.5 m |
| Collecting area | 4.5 m² | 25.4 m² |
| Primary wavelength | UV / Visible | Near + Mid Infrared |
| Operating temp | ~15°C | −233°C (40 K) |
| Orbit | 570 km LEO | L2 point, 1.5 million km |
| Launch | 1990 | December 25, 2021 |
| Total cost | $4.7B | $10B |
Why infrared?
Infrared light can pass through dust clouds that block visible light — letting JWST see into stellar nurseries and the atmospheres of exoplanets. It also detects the redshifted light of the earliest galaxies: light emitted as visible UV when the universe was 300 million years old has been stretched by cosmic expansion into the infrared by the time it reaches us.