Anton M. Koekemoer

A massive galaxy cluster acts as a giant lens. Its gravity warps the fabric of space, and the light of distant objects, bending around this curvature, is amplified and split into multiple images.

Thanks to gravitational lens — an effect predicted by Fritz Zwicky, where a galaxy cluster acts like a magnifying glass — the James Webb Space Telescope spotted two red dots in a galaxy 800 million years after the Big Bang.

The kitchen of a distant galaxy isn't limited to its bright disk. Around every star system, there's an invisible cloud of gas, like steam above a pot of soup. Astronomers peeked into this steam around galaxies that appear as they were just one and a half billion years after the Big Bang.

The Universe looks like a giant spiderweb: galaxies aren't scattered randomly but are gathered into knots and along filaments. Inside the filaments, there's plenty of gas, and that's where new stars most often flare up. But how has this changed over time? Scientists compared data from a computer model with real observations of thousands of galaxies.

Light from the distant Dragon Galaxy has been traveling toward us for more than seven billion years. On its way, it passes by a huge galaxy cluster whose gravity bends the path of light like a lens. As a result, the galaxy appears brighter and larger than it really is, just as a magnifying glass enlarges fine print.

Heir to the ideas of Edwin Hubble, the James Webb Space Telescope has peered back to an era when the expansion of the universe was still picking up speed. At redshifts z>4, it spotted bizarre objects—"Little Red Dots" (LRDs).

The early Universe is often imagined as a nursery: most galaxies there are amorphous blobs, rowdy and irregular, choking on gas and bursts of star formation.

The Universe is less than a billion years old, yet at its centers already sit black holes with masses of a billion suns. According to the conventional picture, they grew by voraciously devouring matter, but calculations show that 'feeding' must have been almost continuous, while visible quasar flares last only a few million years. So where does all the accreting fuel go?