CAPE CANAVERAL, Fla. (AP) — Neptune’s far-flung moon Nereid may be the last of the planet’s original companions that managed to survive a cosmic crash, scientists reported Wednesday.
Sixteen known moons circle Neptune, our solar system’s eighth and most distant planet. Neptune’s biggest moon, Triton, barged in from the solar system’s frigid outskirts billions of years ago, scattering the planet’s original moons and putting them on destructive collision courses.
A team led by the California Institute of Technology used NASA’s Webb Space Telescope to study Nereid. Their observations suggest that Nereid is no party crasher like Triton and likely survived by escaping into its extreme, elliptical orbit around Neptune.
“What we know about Nereid is very limited. For its size, Nereid is extremely understudied,” said study author Matthew Belyakov, of Caltech.
Neptune has only been visited by one spacecraft, NASA’s Voyager 2 in 1989. Nereid was discovered 40 years earlier by Dutch astronomer Gerard Kuiper, who named the moon after the sea nymphs in Greek mythology.
Roughly 220 miles (350 kilometers) across, Nereid has an extremely eccentric orbit for a moon. It takes practically an entire Earth year for Nereid to orbit Neptune, with the moon passing less than 1 million miles (1.4 million kilometers) from the giant icy planet at one end of its egg-shaped loop and as far as 6 million miles (9.6 million kilometers) at the other end.
Like so many other moons in the outer solar system, Nereid was long suspected of migrating to Neptune's neighborhood from the frigid outlying expanse known as the Kuiper Belt. But using the Webb telescope, scientists determined that Nereid’s composition was inconsistent with Kuiper Belt objects — it had too much ice. That suggests it was part of Neptune's system all along.
“We don’t have all that much evidence left around Neptune — the system doesn’t have very many moons left,” Belyakov said in an email. But the latest observations “strongly rule out” that Nereid wandered by like so many others and got ensnared by planetary gravity.
The findings appear in the journal Science Advances.
This is “an exciting result," said Carnegie Science planetary astronomer Scott Sheppard, who was not part of the study.
The observations show for the first time that Nereid’s peculiar orbit matches “the history we might expect from a moon that originally formed close to Neptune and was later pushed outward from the capture of Triton,” Sheppard said in an email.
Neptune's innermost moons likely formed out of the shattered remains of the originals that were Triton's casualties, according to Belyakov and his team.
All three of the solar system’s other giant planets have more moons, with Saturn topping the charts at 292.
A visiting spacecraft could clinch the Neptunian system's origin story, according to scientists, although none are currently planned.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
This August 1989 image provided by NASA shows the planet Neptune photographed by the Voyager 2 spacecraft, processed to enhance the visibility of small features. (NASA via AP)
This image released by NASA shows the Voyager view of Nereid, a satellite of Neptune, obtained on Aug. 24, 1989. (NASA via AP)
PARIS (AP) — The French Open begins in Paris on Sunday. This guide tells you what you need to know about how to watch the second tennis Grand Slam of 2026 on TV, what the betting odds are, what the schedule is, who the reigning champions are and more:
Play begins Sunday at 11 a.m. local time (0900 GMT, 0500 EDT).
— In the U.S.: TNT, TruTV, HBO Max.
— Other countries are listed here.
Coco Gauff of the United States and Carlos Alcaraz of Spain.
Gauff won the trophy for the first time by defeating top-ranked Aryna Sabalenka 6-7 (5), 6-2, 6-4. Alcaraz rallied from two sets down and saved three match points to beat top-ranked Jannik Sinner 4-6, 6-7 (4), 6-4, 7-6 (3), 7-6 (10-2) for his fifth major title in as many finals. It was Alcaraz’s second straight French Open title. Alcaraz injured his right wrist this season and has withdrawn from the French Open and Wimbledon.
Sabalenka is the women's, and Sinner is the men's. They are ranked No. 1 and the tournament seedings follow the WTA and ATP rankings.
Four-time Roland Garros champion Iga Swiatek is listed by bookmakers as the money-line favorite in the women's singles. She is at +225 ahead of Sabalenka (+275). In the men's draw, in the absence of the injured Alcaraz, Sinner is the overwhelming favorite at -300, ahead of Alexander Zverev at +750.
— Sunday through Tuesday: First Round (Women and Men)
— Wednesday-Thursday: Second Round (Women and Men)
— May 29-30: Third Round (Women and Men)
— May 31-June 1: Fourth Round (Women and Men)
— June 2-3: Quarterfinals (Women and Men)
— June 4: Women’s Semifinals
— June 5: Men’s Semifinals
— June 6: Women’s Final
— June 7: Men’s Final
— Jannik Sinner enters the French Open on a 29-match win streak, chasing a career Grand Slam
— Coco Gauff has a new mindset for title defense and more confidence on her serve
— Sinner opens French Open against wild card
— Elina Svitolina and Marta Kostyuk raise trophies for war-torn Ukraine on the tennis court
— No. 1 Sabalenka calls for boycott if players don’t get bigger cut of Grand Slam revenues
— French Open players plan media protest over prize money share
— Carlos Alcaraz pulls out of Wimbledon because of wrist injury
— 45-year-old Venus Williams to play in French Open women’s doubles with Hailey Baptiste
— Three-star gastronomy is coming to Roland Garros. Organizers are launching The Jardin des Chefs, a new dining area showcasing the best of French cuisine. Some of France's top chefs and pastry chefs will take turns preparing their signature dishes, along with exclusive creations.
— Electronic devices that record players’ biometric data have been authorized on a trial basis for the first time. The initiative is designed to help players gain insights into their physical performance and recovery throughout the tournament, organizers said. Athletes will be allowed to use any device included on the “Player Analysis Technology” list approved by the International Tennis Federation. The trial will begin at Roland Garros and continue at the other Grand Slam tournaments this year.
Top players have expressed “their deep disappointment” at the French Open prize money. Open organizers announced an overall prize money increase by about 10% for an overall pot of 61.7 million euros ($72.1 million). The total amount is up 5.3 million euros from last year. But the players said their share of Roland Garros revenue has declined from 15.5% in 2024 to 14.9% projected in 2026. The Australian Open this year increased the players’ pay by 16%, and the U.S. Open last year went up by 20%.
Both, as you can read about in this AP story from 2019. English speakers tend to use “French Open,” although the French Tennis Federation doesn’t call it that. The French — and much of the rest of the world — go with “Roland Garros,” which is the facility that hosts the tournament and is named after a World War I fighter pilot.
The French Open is played outdoors on red clay courts at Roland-Garros on the southwest outskirts of Paris. Women play best-of-three-set matches with a first-to-10 tiebreaker at 6-all in the third; men play best of five with a tiebreaker at 6-all in the fifth. There are separate day and night sessions most days. The event lasts 15 days. There is a retractable roof on the main stadium, Court Philippe-Chatrier.
AP tennis: https://apnews.com/hub/tennis
The men's, left, and women's trophies are displayed during the draw for the French Open tennis tournament, Thursday, May 21, 2026, at the Roland Garros stadium in Paris. (AP Photo/Thibault Camus)
French tennis federation President Gilles Moretton, from left, United States' Coco Gauff, Roland-Garros tournament director Amelie Mauresmo and IOC member Tony Estanguet pose next to the trophies during the draw of French Open tennis tournament, Thursday, May 21, 2026, at the Roland Garros stadium in Paris. (AP Photo/Thibault Camus)
A ballgirl stands during the draw for the French Open tennis tournament, Thursday, May 21, 2026, at the Roland Garros stadium in Paris. (AP Photo/Thibault Camus)
Jannik Sinner, of Italy, wears shoes in the Italian flag colors after defeating Casper Ruud, of Norway, 6/4, 6/4 in the final match to win the Italian Open tennis tournament, in Rome, Sunday, May 17, 2026. (AP Photo/Andrew Medichini)
United States' Coco Gauff reacts as she plays against Ukraine's Elina Svitolina during their women's final match at the Italian Open tennis tournament in Rome, Saturday, May 16, 2026. (AP Photo/Andrew Medichini)
Jannik Sinner, of Italy, reacts after defeating Casper Ruud, of Norway, 6/4, 6/4 in the final match at the Italian Open tennis tournament, in Rome, Sunday, May 17, 2026.(AP Photo/Alessandra Tarantino)
