700-Meter Asteroid Found Hiding in Sun's Glare, One of Fastest Known Orbits

A roughly 700-meter-wide asteroid with one of the fastest known orbits in the Solar System has been confirmed by astronomers, after being found in a region of sky so close to the Sun that most telescopes cannot search it. The object, designated 2025 SC79, takes only 128 days to complete one trip around the Sun, according to Carnegie Science, the US research institution whose astronomer made the discovery.

Who found it, and how

Carnegie Science astronomer Scott S. Sheppard discovered 2025 SC79 on September 27, 2025, using the Dark Energy Camera mounted on the National Science Foundation's 4-meter Víctor M. Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile. Follow-up observations to confirm the orbit were carried out with the NSF's Gemini telescope and Carnegie Science's own Magellan telescopes, the institution said in its announcement.

According to Carnegie Science, the search specifically targets the 'twilight zone' close to the Sun, where sunlight drowns out the faint reflected light of small asteroids. Objects there can only be observed briefly during sunrise or sunset conditions, making them far harder to find than asteroids visible at night.

Why its orbit stands out

According to Wikipedia's entry on the object, 2025 SC79 belongs to the Atira group of asteroids, whose orbits lie entirely inside Earth's path around the Sun. Its 128-day orbital period makes it the third-shortest known for any asteroid, behind 2021 PH27 and 2025 GN1, which both orbit in 113 days, Wikipedia states, citing minor-planet orbital data.

Universe Magazine, an astronomy news outlet, reported that 2025 SC79's orbit lies almost entirely inside that of Venus, with a perihelion distance of about 0.45 astronomical units (roughly 67.3 million kilometers). That makes it only the second known asteroid with an orbit confined inside Venus's, after 594913 'Ayló'chaxnim, discovered in 2020, Universe Magazine said.

The asteroid also crosses the orbit of Mercury during its circuit around the Sun, Carnegie Science noted.

What is and isn't known about the risk

Carnegie Science's announcement frames the discovery as part of a broader, NASA-supported effort to find large asteroids hiding in the Sun's glare before they could pose a danger to Earth. Sheppard was quoted by Carnegie Science as saying that 'the most dangerous asteroids are the most difficult to detect,' referring to twilight objects in general rather than a confirmed threat from this specific asteroid.

Universe Magazine reported that 2025 SC79's path could, in principle, intersect with Venus and that YORP effect — a slow alteration of spin caused by sunlight and heat radiation — could eventually break the asteroid apart, though this process would take less than a million years. No source reviewed for this article reports a confirmed impact probability with Earth for 2025 SC79; none list it on current near-Earth-object risk rankings.

The asteroid has now moved behind the Sun from Earth's vantage point and will be unobservable by telescopes for several months, Carnegie Science said, meaning astronomers will have to wait before refining its orbit further.

Background: hunting asteroids in the Sun's glare

The search that found 2025 SC79 is designed to catch so-called 'planet killer' candidates that orbit close to the Sun and are therefore only visible briefly at twilight, according to Carnegie Science. Because conventional night-sky surveys rarely point telescopes so close to the Sun, this part of the sky has historically been under-searched, leaving open the possibility that comparable objects remain undetected.