Skip to Content

Astronomers have spotted a small first-of-its-kind object in the Kuiper Belt

January 29, 2019

The discovery, made using amateur telescopes, could give researchers a better understanding of how planets evolve.

The findings: You don’t need anything fancy to make discoveries in space. Using just two 28-centimeter telescopes on the roof of a building, researchers from the National Astronomical Observatory of Japan have discovered the first Kuiper Belt object with a radius between one and 10 kilometers. It measures just 2.6 kilometers in diameter. This may seem like an oddly specific thing to be celebrating, but objects like this can provide important clues about how planets are made.

Way out there: The Kuiper Belt is filled with a mix of items, likely left over from the solar system’s formation, that reside beyond Neptune’s orbit. Probably the most famous Kuiper Belt object: Pluto.

Why are we just finding the first one? Objects this size aren’t very bright, and that makes them incredibly difficult to pick up, even with powerful telescopes. So rather than looking for it directly, the research team spotted it using occultation, a technique in which you watch for objects moving in front of a number of stars. When the object passes in front, it blocks out some of the light the star emits. To find this one item, the two amateur telescopes watched 2,000 stars for 60 hours.

Why it matters: While scientists expected objects of this size to exist, this confirmation—outlined in Nature Astronomy—supports models predicting that small planets began as kilometer-size objects before their growth took off.

Want to keep up with the latest space news and technologies? Sign up for our newest newsletter, The Airlock!

Deep Dive


How the James Webb Space Telescope broke the universe

Scientists were in awe of the flood of data that arrived when the new space observatory booted up.

NASA’s return to the moon is off to a rocky start

Artemis aims to deliver astronauts back to the lunar surface by 2025, but it’s riding on an old congressional pet project.

James Webb Space Telescope: 10 Breakthrough Technologies 2023

A marvel of precision engineering, JWST could revolutionize our view of the early universe.

What’s next in space

The moon, private space travel, and the wider solar system will all have major missions over the next 12 months.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at with a list of newsletters you’d like to receive.