UK's Royal Astronomers join the hunt for Ramadan's crescent moon

How to sight the new crescent moon that starts Ramadan

Ramadan doesn't begin on a fixed date. Instead, it begins when a crescent moon is visually confirmed. The Royal Museums Greenwich explains the astronomy behind the sighting, including the conditions that must be met: the sun must be below the horizon, the moon must be above it, and the two must not be within the Danjon Limit (roughly 5 to 7 degrees of separation in the sky, as shown below).

Ramadan moon-sighting can spark intra-family disputes

Because different communities—and even different members of the same family—follow different methods for confirming the crescent, Ramadan doesn't always start on the same day for everyone. The result: "moon wars" that pit parents against children, and mosques against each other, on when exactly the fast begins.

Muslims fasting in Iceland face more than 20 hours of daylight during summer Ramadan

In countries near the Arctic Circle, Ramadan's rule of fasting from sunrise to sunset can cause some unique challenges for the extended periods of daylight in the region. Icelandic Muslims have developed pragmatic workarounds—some follow the hours of Mecca, others adjust locally. It's an edge case that illuminates how a 7th-century practice gets negotiated across radically different geographies.

Ramadan is a major television event in the Middle East

Each year, major networks air special 30-episode dramas timed to the month—one episode per night after iftar. Syrian productions long dominated the format, though that has shifted. The season is the advertising event of the year across the Middle East, rivaling the Super Bowl in commercial intensity.

Ramadan will be celebrated twice in 2030 due to the 33-year lunar cycle

Because the Islamic year is 11 days shorter than the Gregorian calendar, Ramadan migrates through every season over a 33-year cycle. In 2030, it will fall twice in the same Gregorian year.

For the medievals, the moon was a versatile religious symbol

Within the distinct traditions of Christianity and Islam, the moon became a central metaphor and sign for religious teaching. For Christians, its light was used to explain Jesus' humanity with the light of the sun (divinity). For Muslims, the moon represented a cosmic longing for god.

Laylat al-Qadr: the single Islamic night 'holier than a thousand months'

Toward the end of Ramadan, Laylat al-Qadr is observed, recalling Muhammad's "night of power" when the Quran was first revealed, according to Islamic tradition. The Quran describes it as better than a thousand months of worship. Its exact date differs between Sunni and Shia adherents, falling on the 27th night of the month for Sunnis and the 23rd for Shias.

The accidental birth of radio astronomy and the benefits of a moon-based telescope

Detecting radio waves from distant celestial objects is complicated by noise from solar wind, which the nighttime side of the moon is shielded from. If lunar temperature extremes can be overcome, the environment may serve as an optimal future home for radio astronomy, a field that began in 1928 when a 30-meter-long directional antenna, mostly out of brass and wood, picked up signals from the Sagittarius constellation.

Ramadan tends to reduce Gulf productivity, but increases reported happiness

Economists have documented a measurable dip in productivity and output in Muslim-majority countries during Ramadan. But surveys consistently show the opposite on subjective well-being, with people reporting they feel better and more connected.

See a lunar eclipse share the night sky with the Milky Way

Photos taken at the Cerro Tololo Inter-American Observatory in Chile in March 2025 captured a blood moon and the Milky Way galaxy within the same field of view. The moon appears red from the bluer parts of its reflected sunlight being scattered by Earth's atmosphere.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

India's space program began in a church at Earth's magnetic equator

As the US pushed to land a man on the moon, NASA looked for global partners to help map the conditions of the sky above Earth for launches. After Pakistan's initial attempt was sidelined, India pushed to be that partner. This long read details key episodes of frugality and ingenuity in India's space race, including its beginnings at St. Mary Magdalene Church in Thumba.

London Mayor Sadiq Khan on why iftar at someone else's table is the whole point

The podcast "Not Even Water" interviews Khan about how Ramadan is actually lived, examining the hospitality culture that surrounds iftar, the logistics of suhoor, and what the month feels like from the inside. The episode is a grounded, personal view of the season.

Watch the sunset at Stonehenge during the 2025 Summer Solstice

Each year, tens of thousands gathered at Stonehenge to witness the sun’s alignment with the stones during the solstice. Watch a replay of a lifestream of the event from 2025.

Through 2025, two-thirds of known exoplanets have been detected via transits

This technique involves observing periodic, consistent dips in a star's brightness caused by an exoplanet passing in front of it. Observing wobbles in a star as it is pulled by an orbiting exoplanet's gravity has become the second most common detection method, followed by microlensing and direct exoplanet observation.

Photographer catches a 'once in a blue moon' shot

A rare "super blue moon" occurred in August 2023, a phenomenon which will not occur again until 2037. Photographer Andrew McCarthy caught a stunning image of the larger-than-normal orb with an ironic twist: a JetBlue flight silhouetted against the...

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

Explained: The Year of the Rabbit

One of the world's largest holidays, this visual guide will help you welcome the Year of the Rabbit and celebrate the new lunar year.

Emulating Earth’s light-dark cycle is important for astronaut health and safety

Astronauts aboard the International Space Station experience 16 daily sunrises, but scientists have learned to try to promote circadian rhythms by phasing through several light settings aboard the ISS to improve astronauts’ sleep and productivity.

Find which comets are currently visible in the night sky

Incorporating sightings reported in the Comet Observation database and information from NASA's Jet Propulsion Laboratory, this list provides a finder chart, star map, tracker, simulated orbit, and key properties for each comet, all viewable based on a user's input position on Earth.

Ten underrated astronomy studies from 2022

The James Webb Space Telescope understandably received a lot of coverage in 2022. This astrophysicist wants to highlight ten major studies published last year you might have missed.

The Astronomical Congress designated 88 groups of stars as official constellations

This 1928 decision helped distinguish important groups of stars used in navigation, calendars, and mythological storytelling from miscellaneous collections of stars called asterisms. The Big Dipper is a famous asterism in the constellation Ursa Major.

Early timekeeping tools included sundials, water clocks, and astrolabes

Astrolabes also provided a person's latitude based on the height of the stars in the sky, thus aiding in navigation. Incense and candle clocks relied on the constant burning rate of fire to track the passage of time based on premarked locations with equal-interval spacing.

Zoom from Earth to Maisie's galaxy

Discovered by the Webb Telescope in 2022, Maise’s Galaxy (named after the nine-year-old daughter of the scientist who discovered it) was found as part of a survey of a section of the universe known as the Extended Growth Strip, home to thousands of galaxies. This video takes you from Earth to Maise’s galaxy, formed roughly 300 million years after the birth of the universe.

British royal history from a literal bird's-eye view

Learn the history of British monarchs going back centuries with this unusual, 50-minute documentary filmed entirely from the air, revealing key landmarks in beautiful footage alongside engaging commentary.

One man in Arizona works to defend Earth from catastrophic space rocks

David Rankin, an observer and operations engineer at the NASA-funded Catalina Sky Survey, spends his days scanning for solar system objects that could collide with our planet. The job requires employees to work long shifts to help prevent asteroids from destroying our planet.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

'Silent' fireworks have gained more interest in recent years as a quieter celebratory option.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

This real-time tracking of the hantavirus cruise ship outbreak in May 2026 offers a unique glimpse into the global reach of the outbreak and whether the virus sickened passengers and their communities around the world.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

Hotels in Cannes, the glamorous city on the French Riviera, hire hawks to ward off seagulls during the city's famous film festival.

In 2009, the nation was gripped by the story of a missing young boy who was believed to be floating over Colorado in a homemade balloon, until it was revealed that he was at home the whole time.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

The distributor behind 'Rocky Horror' pulled the film from its scheduled national release, believing it would be a failure, though it eventually amassed a dedicated fanbase through midnight showings, a trend that continues over 50 years later.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

In preparation for this weekend's Eurovision finale, which is something like the World Cup of pop music, here's a young Céline Dion performing (for Switzerland?) at the 1988 competition.