10 of the Most Fascinating Things Ever Found in Space

Videos like the one above are a fun way to get hooked on space. To make this post more useful, here is our own countdown of ten genuinely fascinating discoveries, each checked against NASA, ESA and other reputable sources, with a short note on why it matters.

1. The first image of a black hole (2019)

In April 2019 the Event Horizon Telescope collaboration, which links radio dishes around the world into a single Earth-sized telescope, released the first image of a black hole’s shadow, at the centre of the galaxy M87 about 55 million light-years away. In 2022 the team followed up with an image of Sagittarius A*, the black hole at the heart of our own Milky Way, about four million times the mass of the Sun.

2. Ripples in space-time (2015)

On 14 September 2015 the LIGO detectors recorded gravitational waves from two black holes merging about 1.3 billion light-years away, confirming a prediction from Einstein’s general relativity. The discovery earned the 2017 Nobel Prize in Physics and opened an entirely new way to observe the universe.

3. Thousands of planets around other stars

The first planet found orbiting a Sun-like star, 51 Pegasi b, was announced in 1995. Today NASA has confirmed more than 6,000 exoplanets, including lava worlds, planets lighter than foam and the seven Earth-sized planets of TRAPPIST-1. NASA now says there are likely more planets than stars in our galaxy.

4. The Hubble Deep Field (1995)

Hubble spent ten days staring at a tiny, apparently empty patch of sky in Ursa Major and found roughly 3,000 galaxies. It showed that even the “empty” sky is packed with galaxies, many seen as they were billions of years ago.

5. Water plumes on Enceladus

NASA’s Cassini spacecraft discovered jets of water vapour and ice erupting from cracks near the south pole of Saturn’s small moon Enceladus. Flying through them, Cassini found salts, organic molecules and signs of hydrothermal activity in a hidden ocean, making Enceladus one of the best places to look for life beyond Earth.

6. The Pale Blue Dot (1990)

On 14 February 1990, at Carl Sagan’s suggestion, NASA’s Voyager 1 turned its camera back toward home from about 6 billion km away. In the resulting image Earth is less than a single pixel, a tiny speck in a scattered sunbeam. It remains one of the most moving pictures ever taken.

7. A planet-forming disc around a young star (2014)

The ALMA radio telescope in Chile, operated by ESO and international partners, captured a sharp image of the young star HL Tauri surrounded by a disc of dust with clear gaps, likely being carved out by planets forming inside it. It was a direct look at how planetary systems, possibly like ours, are born.

8. The cosmic microwave background (1965)

Arno Penzias and Robert Wilson found a faint, uniform hiss of microwaves coming from every direction in the sky. It turned out to be the afterglow of the Big Bang, light released when the universe was about 380,000 years old. Satellites such as NASA’s COBE and WMAP and ESA’s Planck later mapped it in detail, revealing the seeds of today’s galaxies.

9. Pulsars (1967)

Jocelyn Bell Burnell, then a graduate student, noticed a radio signal pulsing with perfect regularity. It was the first known pulsar: a neutron star, the collapsed core of a massive star about 20 km across, spinning and sweeping beams of radiation past Earth like a lighthouse.

10. The dark energy surprise (1998)

Two teams studying distant exploding stars, Type Ia supernovae, expected to find that the expansion of the universe was slowing down. Instead they found it is speeding up. The mysterious cause is called dark energy, and it makes up roughly two-thirds of the universe’s total energy. The discovery won the 2011 Nobel Prize in Physics.

Honourable mentions

A few more worth looking up: Pluto’s heart-shaped glacier revealed by New Horizons in 2015; the interstellar visitors ‘Oumuamua (2017), 2I/Borisov (2019) and 3I/ATLAS (2025); and the James Webb Space Telescope’s deep images of galaxies seen only a few hundred million years after the Big Bang.

Why these discoveries matter

Almost every item on this list was a surprise, or confirmed something once thought impossible to measure. That is what makes astronomy exciting: each new telescope or mission tends to reveal something nobody predicted. Many of these images, including the Pale Blue Dot, the Hubble Deep Field and the black hole images, are freely available on NASA, ESA and ESO websites, and they make wonderful starting points for your own exploring.

See something fascinating tonight

You do not need a space telescope to see something amazing. On a clear, dark night, look for the Andromeda Galaxy, the most distant object easily visible to the naked eye at about 2.5 million light-years. Or watch for a meteor: a grain of dust left behind by a comet, burning up in our atmosphere at tens of kilometres per second.