Level 1 — Absolute Beginner
Scientists use big telescopes to look at space. NASA has a telescope named Hubble. NASA, ESA, and CSA have a telescope named Webb. Hubble looks at light we can see. Webb looks at a different kind of light called infrared light.
In September 2026, scientists used Hubble and Webb together for the first time. They looked for very small, very dim objects far out in space, past the planet Neptune. These objects are called trans-Neptunian objects.
The scientists found 27 new objects. The smallest one is only 5 km wide. That is very small for something in space. Scientists say finding it is like seeing a tiny firefly on the Moon from Earth.
These small icy objects are very old. They are about 4.5 billion years old. They are pieces left over from when the solar system was made. Scientists found fewer small objects than they expected, and they still have questions about them.
- telescope
- a tool that helps people see far away objects, like stars and planets
- space
- the huge area outside Earth where planets and stars are
- infrared light
- a kind of light that human eyes cannot see, but special telescopes can
- planet
- a large round object that moves around the Sun
- object
- a thing, especially something you can see or touch
- dim
- not bright, hard to see
- icy
- made of ice or covered in ice
- billion
- a very big number, one thousand million (1,000,000,000)
Level 2 — Elementary
For the first time, astronomers used two powerful NASA telescopes together to search the far edges of our solar system. They joined the Hubble Space Telescope, which sees visible light, with the James Webb Space Telescope, run by NASA, ESA, and CSA, which sees infrared light. Together, in September 2026, the two telescopes helped scientists find some of the smallest, faintest objects ever spotted so far from the Sun.
The team discovered 27 previously unknown trans-Neptunian objects. These are small, icy bodies that travel around the Sun far beyond the planet Neptune, out in the dark, cold edge of the solar system. The tiniest of these new objects measures only about 5 km, or 3 miles, across, making it one of the smallest and faintest objects any telescope has ever directly seen.
Scientists compared the difficulty of spotting the dimmest object to trying to see a firefly on the Moon while standing on Earth. These icy bodies are thought to be leftover building blocks from the early solar system, material that never joined together to form a full planet, and they are believed to be about 4.5 billion years old.
Researchers were surprised that they found fewer small trans-Neptunian objects than their models had predicted. They also noticed that the small objects share the same color patterns as their larger, already known relatives. Scientists still do not fully understand how these small, fragile looking icy worlds have kept their original chemistry for 4.5 billion years, especially since this distant region of space turns out to be less calm than once believed.
- astronomer
- a scientist who studies stars, planets, and other objects in space
- visible light
- the light that human eyes can naturally see
- faint
- weak in light or brightness, hard to detect
- discover
- to find something that was not known before
- leftover
- something remaining after the rest has been used or finished
- fragile
- easily broken or damaged
- distant
- far away in space or time
- chemistry
- the substances and materials that make up something, and how they behave
Level 3 — Intermediate
In a milestone for outer solar system research, astronomers have for the first time combined observations from NASA's Hubble Space Telescope and the NASA/ESA/CSA James Webb Space Telescope to hunt for some of the smallest, faintest objects ever detected beyond Neptune. Announced in September 2026, the project paired Hubble's sensitivity to visible light with Webb's ability to detect infrared light, giving astronomers a far more complete picture of these objects' size, color, and composition than either instrument could provide alone.
The joint effort turned up 27 previously unknown trans-Neptunian objects (TNOs), small icy bodies that orbit the Sun far beyond Neptune in the solar system's outer darkness. The smallest of these newly identified worlds spans just 5 km, roughly 3 miles, placing it among the smallest and faintest objects any telescope has directly imaged. Researchers likened the challenge of detecting the dimmest object to spotting a firefly on the Moon from the surface of Earth.
These tiny icy bodies are considered relics from the solar system's earliest construction phase, material that never accreted into full planets, and are estimated to be roughly 4.5 billion years old. Notably, the team found fewer small trans-Neptunian objects than their models had predicted, a result that complicates existing theories about how many small bodies should remain in this region.
The newly found objects display the same color patterns as their larger, previously catalogued relatives, yet scientists still cannot explain how such small, seemingly fragile icy worlds have preserved their original chemistry across 4.5 billion years. That puzzle is sharpened by growing evidence that this distant region is not the calm, undisturbed environment scientists once assumed, raising fresh questions about what has protected these ancient fragments from disruption.
- milestone
- an important event or achievement that marks progress
- sensitivity
- the ability of an instrument to detect small or weak signals
- composition
- the substances or parts that something is made of
- accrete
- to gradually grow larger by the accumulation of additional material
- relic
- an object that has survived from an earlier time
- catalogue
- to record or list something formally, often in an organized collection
- disruption
- disturbance or interruption that breaks apart the normal state of something
- preserve
- to keep something in its original or existing state
Level 4 — Advanced
Astronomers have, for the first time, fused observations from NASA's Hubble Space Telescope with those of the NASA/ESA/CSA James Webb Space Telescope to probe the faintest, smallest reaches of the outer solar system, a collaboration announced in September 2026. By pairing Hubble's acuity in visible light with Webb's command of infrared, researchers assembled a far richer portrait of size, color, and composition than either observatory could yield in isolation, a methodological leap likely to shape how such surveys are conducted going forward.
The campaign yielded 27 previously undocumented trans-Neptunian objects (TNOs), icy remnants that circle the Sun far beyond Neptune in the solar system's outer gloom. The smallest among them measures a mere 5 km, about 3 miles, across, ranking it among the smallest and faintest bodies ever directly resolved by any telescope, a feat researchers described as comparable to discerning a firefly on the Moon from the vantage of Earth.
These diminutive icy bodies are understood to be relics of the solar system's formative epoch, raw material that never coalesced into full-fledged planets, and are reckoned to be some 4.5 billion years old. Yet the survey's most consequential finding may be a negative one: researchers detected markedly fewer small TNOs than prevailing models had anticipated, a discrepancy that unsettles assumptions about the population and evolution of this remote belt.
Compounding the puzzle, the newly catalogued objects exhibit color signatures that mirror those of their larger, long-known counterparts, yet how such small, seemingly fragile icy worlds have retained their primordial chemistry across 4.5 billion years remains unresolved, particularly as mounting evidence suggests this distant frontier is considerably less placid than once assumed. Reconciling that apparent durability with a more turbulent environment stands as one of the more intriguing open questions to emerge from the observations.
- acuity
- sharpness or keenness in perception or detection
- remnant
- a small remaining part or trace of something larger or earlier
- resolve
- in astronomy, to see or image an object clearly and distinctly
- discern
- to perceive or recognize something, especially something faint or subtle
- coalesce
- to come together and combine into a single mass or whole
- primordial
- existing from the very beginning, original and unchanged
- placid
- calm and peaceful, undisturbed
- reconcile
- to make two seemingly conflicting things consistent with each other
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