China captures first images of Earth's second moon, a quasi-satellite asteroid.

Scientists have secured the first visual confirmation of a rare celestial object looping around Earth, effectively revealing our planet's second moon. The China National Space Administration (CNSA) has released the initial imagery captured by the Tianwen-2 probe, which approached asteroid 2016 HO3, also designated Kamoʻoalewa. The photograph displays a grey, jagged space rock set against the void of deep space. Although the object is too distant to be classified as a true satellite, it represents the most stable example to date of a near-Earth companion, known as a quasi-satellite.

The Tianwen-2 probe completed a 400-day journey spanning one billion kilometers to reach the target. On July 2, the spacecraft closed the distance to just 20 kilometers, or 12.4 miles, allowing it to acquire the high-resolution data now available to the public. This mission marks a critical milestone in CNSA's first asteroid sample-return campaign. The probe launched from the Xichang Satellite Launch Center on May 29, 2025, and performed its first optical detection of Kamoʻoalewa on June 6. By June 19, the vessel had drawn within 1,242 miles, and by July 2, it was positioned close enough to capture the clear image of the rock, which measures between 40 and 100 meters in diameter.

Discovered in 2016 by the Pan-STARRS 1 telescope on Haleakala in Hawaii, Kamoʻoalewa orbits the sun while tracing a circular path around Earth. Its name references an offspring that travels independently, reflecting its unique orbital mechanics. Physicist Rongqiao Zhang from the Lunar Exploration and Space Engineering Centre in Beijing highlighted the object's exceptional rarity. He noted that among known near-Earth asteroids, 2016 HO3 is one of only seven identified Earth co-orbital objects. Zhang emphasized that the asteroid's orbital period closely matches that of Earth, enabling low-energy transfer and favorable conditions for tracking, control, and communication.

The object's enigmatic origin and largely uncharacterized physical properties make it a compelling subject for addressing fundamental questions regarding the origins of Earth's quasi-satellites and the dynamical evolution of their orbits. Currently, Kamoʻoalewa sits approximately 25.8 million miles away from Earth. The Tianwen-2 mission is designed to conduct in-orbit observations of the rock and will attempt to collect samples for return to Earth, providing unprecedented access to data on this elusive celestial neighbor.

Tianwen-2 will spend nine months orbiting asteroid 2016 HO3 before returning to Earth. The probe releases a sample capsule during its flyby between the fifth and sixth months of the mission. It then heads toward main-belt comet 311P for a visit between the seventh and ninth months.

Returning samples will confirm whether 2016 HO3 is a fragment of the Moon. Previous studies suggested this possibility. Renu Malhotra, a space expert at the University of Arizona, notes that reflected light matches minerals from Apollo lunar rocks.

Paul Chodas, manager of NASA's Centre for Near-Earth Object Studies, first described the object's unique path. He stated that 2016 HO3 loops around Earth without venturing far while both bodies orbit the Sun. Calculations show it has remained a stable quasi-satellite for nearly a century. Earth's companion status will likely continue for centuries.

During its yearly solar orbit, the asteroid spends half its time closer to the Sun than Earth. It passes ahead of our planet during this phase. For the other half, it moves farther away and falls behind Earth. Its orbit tilts slightly, causing it to bob up and down through Earth's orbital plane once annually.

This small asteroid engages in a centuries-long leapfrog dance with Earth. Its orbit twists slowly back and forth over multiple decades. Dr. Chodas explained that the asteroid's loops drift ahead or behind each year. Earth's gravity reverses the drift when it becomes too strong. This force keeps the asteroid within about 100 times the Moon's distance.

The same gravitational effect prevents the asteroid from approaching closer than roughly 38 times the Moon's distance. Dr. Chodas described this dynamic as a little dance with Earth. Tianwen-2 drops off its sample capsule during the planned Earth flyby. The mission then continues toward comet 311P beyond Mars.