The British astronomer and mathematician Edmond Halley was not, after all, the first to understand the cycle of the comet that now bears his name. This is shown by research conducted by, among others, Professor Simon Portegies Zwart. It was the monk Eilmer of Malmesbury who, as early as the 11th century, linked two observations of the comet.

The events are described by the 12th-century chronicler William of Malmesbury, but until now this has gone unnoticed by scholars. Portegies Zwart and Lewis now argue that Aethelmaer witnessed both appearances of the comet. Their findings have been published in the book 'Dorestad and Everything After. Ports, townscapes & travellers in Europe, 800-1100'.

Halley identifies the comet's periodicity

Halley discovered that the very bright periodic comet later named after him, 1P/Halley, observed in 1531, 1607 and 1682, was in fact the same comet, returning approximately every 76 years.

Recently discovered Comet C/2025 R3 (PanSTARRS) will make its closest approach to the sun and Earth in late April and could potentially be visible to the naked eye. It may end up being the brightest comet of the year.
We may be less than two weeks into 2026, but a new comet is already leading the charge to become the "Great Comet" of the year. The highly anticipated ice ball, which could potentially be seen with the naked eye, will reach its closest point to us less than four months from now.

Scientists discovered the incoming comet, dubbed C/2025 R3 (PanSTARRS), on Sept. 8, 2025, in images captured by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) — a pair of 5.9-foot (1.8 meters) reflector telescopes located on the summit of Hawaii's Haleakalā volcano. It is currently around 216 million miles (348 million kilometers) from Earth, around halfway between the orbits of Jupiter and Mars, according to TheSkyLive.com.

C/2025 R3 is a long-period comet, meaning it likely takes more than 1,000 years to orbit the sun, and probably originates from the Oort cloud — a giant reservoir of comets and other icy objects near the edge of the solar system. Astronomers have yet to narrow down the comet's orbital pathway, so they do not know how long the ice ball takes to circle our home star. But similar discoveries in recent years have revealed comets that have not passed by Earth for tens of thousands of years.

C/2025 R3 is currently speeding toward the sun and will reach perihelion — its closest point to our home star — on April 20. It will come within 47.4 million miles (76.3 million km) of the sun, which is somewhere between the orbits of Mercury and Venus.

Just one week later, on April 27, the comet will make its closest approach to Earth, coming within 44 million miles (70.8 million km) of our planet, which is more than 180 times farther from us than the moon is.

Astronomers don't yet know how brightly the comet will shine during its solar flyby, Live Science's sister site Space.com recently reported. Some researchers have predicted that it will reach an apparent magnitude of 8, meaning it would be visible only via a decent telescope or pair of stargazing binoculars. But others estimate that it could reach magnitude 2.5, which would make it clearly visible to the naked eye. (Apparent magnitude is measured on a reverse logarithmic scale, meaning a lower number equates to a greater brightness.)

New images show that comet C/2025 K1 (ATLAS) has fragmented after passing its closest point to the sun, ahead of its close approach to Earth later this month. This is not the interstellar comet 3I/ATLAS.

The "other" Comet ATLAS has fragmented, transforming into a cloud of debris that's streaming into space, new observations have revealed.

The comet, called C/2025 K1 (ATLAS), was discovered in May by astronomers at the Asteroid Terrestrial-impact Last Alert System (ATLAS) and passed perihelion, or closest point to the sun, on Oct. 8. It has no relation to the famous interstellar comet 3I/ATLAS, other than having been discovered by the same telescope network around the same time.

Initial observations appeared to suggest that Comet K1 survived its passage around our star at a minimum distance of 31 million miles (50 million kilometers), or roughly four times closer than Comet 3I/ATLAS got.

However, new observations taken by astronomer Gianluca Masi in Manciano, Italy, show that the gravitational strain of its voyage around the sun was too much for the comet, causing it to fragment into several pieces, or clouds.

"Several parts (sub-nuclei or clouds of debris) are visible, also a plume just below the leading (the first from the left) fragment," Masi, an astronomer at the Astronomical Observatory of Campo Catino and the founder of The Virtual Telescope Project, wrote in an update.

After passing behind the sun in October, interstellar Comet 3I/ATLAS is now visible from Earth again. Astronomers are photographing it in the pre-dawn sky.

Michael Jaeger of Austria has been tracking the comet since it re-appeared on Nov. 4th. "We have something unusual to report," he says. "3I/ATLAS showed a complex tail structure early this morning (Nov. 8th)."
"At the time of exposure, the comet was 7-10° above the horizon," he says. "At the end, twilight interfered with the observation, which took place under bright moonlight. We observed from a mountain location."

On 24 Oct. 2025, while imaging comet C/2025 A6 Lemmon, we captured a meteor crossing the same field of view. Soon after, its red afterglow showed so nicely, adding its intriguing, fast evolving shape to the scene.
During the imaging session of comet C/2025 A6 Lemmon on the evening of October 24, I had the good fortune to witness a truly fascinating phenomenon — one that, by sheer chance, I was able to capture.

Between 17:39:30 and 17:41:30 UT, a meteor passed right through the region of the sky where Lemmon was visible.

At that moment, a sequence of wide-field images was being acquired using the astrograph that is part of the Virtual Telescope Project instrumentation, installed in Manciano (Grosseto), in the beautiful Maremma region. In the frame taken between 17:43:33 and 17:45:33 UT, the persistent trail left by the meteor is clearly visible, with a distinct reddish hue. The faint, fan-like structure is likely due to some light which reached the imaging device while capturing the picture.

A new analysis of our solar system's interstellar interloper, 3I/ATLAS, reveals that it's spewing huge amounts of water — and astronomers can't immediately explain why.

The object, which is widely believed to be comet, showed strong ultraviolet emissions that are unmistakable telltales of hydroxyl gas (OH), a byproduct of water, when astronomers imaged it with NASA's Neil Gehrels Swift space telescope before it disappeared behind the Sun. The emissions could only be spotted from space because the ultraviolet light would get absorbed in the atmosphere.

Their findings, detailed in a new study published in The Astrophysical Journal Letters, argue that the presence of all this OH indicates the comet is ejecting water vapor at a torrential rate of about 88 pounds per second — around the same rate as a fire hose running at full blast, according to a press release about the findings.

With so much attention on interstellar Comet 3I/ATLAS, it is easy to forget a local comet brightening so rapidly that ordinary sky watchers will soon be able to see it with their own eyes: Comet Lemmon (C/2025 A6). It is falling toward the sun for a close encounter near the orbit of Mercury on Nov. 8th.

"This comet is developing very nicely and it is already an impressive object, well-placed for observation in the morning sky," says Nick James of the British Astronomical Association. "It is definitely worth getting up for!"

The light curve of Comet Lemmon shows that it is about to cross the threshold (m=+6) of naked-eye visibility:

"I think we can now be reasonably confident that this will be a very nice evening object when it is at its brightest around New Moon in late October," says James.

We don't realize it, but Earth is subjected to a constant cosmic rain of material. The vast majority of it is tiny micrometeors that burn up in the atmosphere, up to 100 tons per day by some estimates. But sometimes, much larger objects strike Earth. The most notable is probably the Chicxulub impactor that wiped out the dinosaurs and left a massive crater, now buried.

There are many other large potential impactors that explode above the surface, called touchdown airbursts, and their effect on Earth is much harder to quantify. New research suggests that a swarm of debris from an exploding comet left its mark by triggering the Younger Dryas, a period of abrupt cooling around 12,000 years ago. The researchers say that the touchdown airburst and the resulting Younger Dryas led to the extinction of megafauna, and the disappearance of the Clovis culture.

Their findings support the Younger Dryas Impact Hypothesis (YDIH) which states that the impact of a disintegrating asteroid or comet is responsible for abruptly cooling the Earth. The YDIH isn't widely accepted in the science community. Critics tout the lack of an impact crater as evidence against the YDIH. They also say that other evidence supporting it can best be explained by other causes.

New research found evidence of comet debris impact at sites of the Clovis culture, a culture that came to an end at the same time as the Younger Dryas. Will this new research lead to wider acceptance of the YDIH?

The research appears in PLOS One. It's titled "Shocked quartz at the Younger Dryas onset (12.8 ka) supports cosmic airbursts/impacts contributing to North American megafaunal extinctions and collapse of the Clovis technocomplex," and the lead author is James Kennett. Kennett is the UC Santa Barbara Emeritus Professor of Earth Science.

An asteroid that struck Chesapeake Bay 35 million years ago left a long trail of destruction in its wake, new research suggests.
Around 35 million years ago, a small asteroid traveling at 40,000 miles per hour (64,373 kilometers per hour) struck Earth, crashing into the Atlantic Ocean near the modern-day town of Cape Charles, Virginia. The approximately 3-mile-wide (5-kilometer) object created a large impact crater that's buried half a mile beneath Chesapeake Bay. Hundreds of miles south of the crater, scientists have found new evidence of the asteroid impact and the tsunami that followed the shattering event.

Hidden beneath the waters of the Chesapeake, the impact crater in Virginia is among the largest and most preserved craters found on Earth. The Chesapeake Bay crater was first discovered in 1990, and scientists are still trying to piece together the trail of destruction left by the asteroid. A team of geologists investigating fossils in Moore County, North Carolina, uncovered layers of rock they determined were forged by the asteroid impact and the tsunami that followed.

In a recently published study in Southeastern Geology, scientists document the far-reaching impact of the asteroid collision, detailing the discovery of a site found approximately 240 miles (386 km) away from the Virginia crater in the Sandhills of North Carolina.

A bright comet has emerged from behind the sun, surprising astronomers. Introducing, Comet SWAN25B;

"The comet is magnitude 7.5, bright enough to see with backyard telescopes," reports Ernesto Guido. "This is our confirmation image taken just a couple hours ago via the Spaceflux network."

The comet is named after the SWAN camera onboard the Solar and Heliospheric Observatory (SOHO). Amateur astronomer Vladimir Bezugly noticed the comet in online images. SWAN is a special camera that maps hydrogen in the solar wind, which suggests this comet may be rich in the element.