Level 1 — Absolute Beginner

An asteroid is a big rock that flies in space. Many asteroids fly around the Sun, like Earth does.

On Monday, May 18, 2026, an asteroid called 2026 JH2 will fly very close to Earth. It will pass by at about 9:23 in the evening UTC time.

The rock is small. It is the size of a big house. But it will be closer to us than the Moon. That is not very common.

NASA says we are safe. The asteroid will not hit Earth. Scientists want to watch it to learn more about space rocks.

asteroid

a large rock that travels around the Sun in space

Earth

the planet where we live

Moon

the round white object that goes around the Earth

rock

a hard piece of stone

space

the area above the sky, where the planets and stars are

close

near, not far away

to fly

to move through the air or space without touching the ground

safe

not in any danger

Level 2 — Elementary

On Monday, May 18, 2026, a small asteroid named 2026 JH2 will make a very close visit to Earth. At 21:23 UTC, it will pass at about 90,000 kilometres from our planet. That is less than a quarter of the distance between the Earth and the Moon.

The asteroid is between 16 and 35 metres wide. That is about the size of a basketball court or a blue whale. It is too small to see without a telescope, but you can watch it on a free livestream from the Virtual Telescope Project in Italy.

The asteroid was only discovered on May 10, just one week before its close pass. A telescope on Mount Lemmon, in Arizona in the United States, spotted it for the first time. The fast discovery shows how well modern sky surveys can find dangerous rocks.

Scientists at NASA say there is no danger. The asteroid will not hit Earth. Even if a rock this size did enter the air, most of it would burn up before reaching the ground.

asteroid

a rocky object that orbits the Sun, smaller than a planet

orbit

the curved path one object takes around another in space

close approach

the moment when a space object passes nearest to the Earth

telescope

an instrument that uses lenses or mirrors to see distant things in the sky

livestream

a video broadcast that is shown on the internet at the same time it is being filmed

Mount Lemmon

a mountain in Arizona, USA, with a famous telescope that hunts for asteroids

discover

to find or see something for the first time

burn up

to be destroyed by heat, often when entering the air at very high speed

Level 3 — Intermediate

A house-sized near-Earth asteroid, designated 2026 JH2, makes its closest approach to our planet at 21:23 UTC on Monday, May 18, 2026. According to data from NASA's Jet Propulsion Laboratory, the object will pass within roughly 90,000 kilometres of Earth — less than a quarter of the average distance to the Moon, and well inside the orbits of every geostationary communications satellite.

The rock measures somewhere between 16 and 35 metres across, comparable in size to the Chelyabinsk bolide that exploded over central Russia in February 2013. Astronomers stress, however, that there is zero impact probability on this approach: the closest miss distance has been refined to within a few hundred kilometres, and 2026 JH2 will not return to Earth's neighbourhood for at least another four decades.

The asteroid was first detected only eight days before its closest approach, by the Mt. Lemmon Survey in southern Arizona — one of several US sky surveys funded by NASA's Planetary Defense Coordination Office. The short discovery interval is being treated as a useful real-world drill for the broader near-Earth-object detection network, which has been preparing for the introduction of the Vera C. Rubin Observatory's far-deeper southern-hemisphere scans later this year.

Although 2026 JH2 will reach an apparent magnitude of only about +11.5 — too faint to see with the unaided eye — it will be within reach of modest backyard telescopes for observers along its track. The Virtual Telescope Project, run by astronomer Gianluca Masi from Ceccano, Italy, is hosting a public livestream beginning before the closest approach so that anyone with an internet connection can follow the encounter in real time.

near-Earth asteroid

an asteroid whose orbit brings it within roughly 45 million kilometres of the Earth's orbit

geostationary orbit

an orbit about 36,000 km above the equator, where satellites stay above the same spot on Earth

Chelyabinsk bolide

a 20-metre meteoroid that exploded over Russia in 2013, injuring more than a thousand people with its shock wave

impact probability

the calculated chance that a tracked object will physically hit the Earth on a given pass

Mt. Lemmon Survey

a NASA-funded telescope programme in Arizona that searches for near-Earth asteroids and comets

Planetary Defense Coordination Office

the NASA division that organises the tracking of and response to hazardous near-Earth objects

Vera C. Rubin Observatory

a new wide-field telescope in Chile that will perform a ten-year survey of the southern sky from 2026

apparent magnitude

a number that measures how bright a star or other object looks to an observer on Earth

Level 4 — Advanced

At 21:23 Universal Time on the evening of Monday, May 18, 2026, the recently identified Apollo-class near-Earth asteroid 2026 JH2 will sweep past our planet at a nominal geocentric distance of roughly 90,000 kilometres — a margin equivalent to less than a quarter of the Earth–Moon separation, and comfortably inside the belt of geostationary communications satellites perched 35,786 kilometres above the equator. Although the rock is large enough to attract every survey scope between Tucson and Tenerife, NASA's Center for Near-Earth Object Studies has assigned it a Sentry impact probability of precisely zero for this apparition and for all close approaches over the next four decades.

Photometric measurements from the Mt. Lemmon 1.5-metre reflector that first recovered the object on the night of May 10 suggest a diameter of 16–35 metres, placing 2026 JH2 squarely within the regime of the 2013 Chelyabinsk bolide and, more provocatively, within the size class of the 1908 Tunguska impactor that levelled some 2,000 square kilometres of Siberian taiga. Yet the parallels end there: the Chelyabinsk parent body was an undetected sneak attack from sunward, whereas 2026 JH2 was tracked, characterised, mass-modelled and posted on the Minor Planet Center's Near-Earth Object Confirmation Page within hours of first light, then handed to follow-up telescopes from Sutherland to Ondřejov for radar and spectral typing.

For planetary-defence scientists, the encounter is less a hazard than a high-stakes proof of concept. Eight days from spotting to closest approach is short relative to the multi-year warning intervals planners crave, but it is leagues ahead of the no-warning Chelyabinsk case and roughly twice the lead time delivered by 2024 BX1 over Berlin two years ago. The drill comes just as the Vera C. Rubin Observatory ramps to first survey light in Cerro Pachón, Chile, an instrument expected to lower the detection floor for sub-50-metre Earth-crossers by an order of magnitude and reshape the statistics that govern policy responses to imminent flybys.

For everyone else, the spectacle is largely cerebral. At a peak apparent magnitude near +11.5, 2026 JH2 sits about ten magnitudes below the unaided-eye threshold — modest backyard equipment can pick it up streaking through the southern constellations, but no naked-eye observer will see anything unusual in the sky. The Virtual Telescope Project, hosted by Roman astronomer Gianluca Masi in Ceccano, Italy, will broadcast a public livestream from a robotic remote-controlled telescope, capturing the brief minutes during which a Chelyabinsk-class rock threads the Clarke belt without anyone on Earth noticing a thing.

Apollo-class asteroid

a near-Earth asteroid with an orbital semi-major axis greater than Earth's that crosses Earth's orbit from outside

geocentric distance

the distance of an object from the centre of the Earth, used by orbital dynamicists rather than surface distance

Sentry impact probability