Discover the cosmos!
Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2025 September 16
Explanation:
A newly discovered comet is already visible with binoculars.
The comet,
C/2025 R2 (SWAN) and nicknamed SWAN25B,
is brightening significantly as it emerges from the
Sun’s direction and might soon become visible on your smartphone —
if not
your eyes.
Although the brightnesses of
comets are notoriously hard to predict,
many comets appear brighter as they approach the Earth, with
SWAN25B reaching only a quarter of the Earth-Sun distance near October 19.
Nighttime skygazers
will also be watching for a
SWAN25B-spawned meteor shower around
October 5 when our Earth passes through the plane of the
comet’s orbit.
The unexpectedly
bright comet was discovered by an
amateur astronomer in images of the
SWAN instrument on
NASA‘s
SOHO satellite.
The comet is currently best observed in southern skies but is slowly moving north.
The featured image was captured at sunset three days ago
just above the western horizon in
Zacatecas,
Mexico.