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During the past couple of weeks, skywatchers around the world have been observing the western evening sky soon after sundown, as four naked-eye planets -- Venus, Mars, Saturn and Jupiter - have stretched out in a long line. The line has slowly contracted each night, as the four planets draw closer to each other.Even the Moon got involved, closely passing each of the four planets over a span of five nights in mid-April. Now through the first days of May will likely be the best time to see yet a fifth planet: Mercury. Mercury has actually been visible for the...

A grand celestial reunion is due in Earth’s skies throughout June. Sky-watchers will get a rare chance to see all the major planets in our solar system bunched together—with the moon joining the festivities, too, from June 17 to June 27. This rare alignment includes the five planets easily spotted with the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn. Each is bright enough to be seen even in light-polluted city skies, with brilliant Venus being the brightest and Mercury the faintest. Our closest planets will appear to be arranged across the sky in the same order as their distance...

Five planets will be visible in the predawn sky this weekend, offering an opportunity for sky watchers to see a rare alignment of Mercury, Venus, Mars, Jupiter and Saturn with the naked eye. Beginning Friday and lasting through this month, the five planets will appear strung across the eastern horizon before sunrise. The parade of planets will be aligned in order of their distance from the sun, with Mercury, closest to the star, appearing lowest on the horizon and Saturn highest in the night sky. For the best views, sky watchers in the Northern Hemisphere should head outside roughly 30...

This Sunday, April 17th, Jupiter will move into position closest to the eastern horizon, and almost on top of Venus. A bit south and above will be Mars looking very red, and then Saturn further up and further south. For most people in North America, the ideal time will be to go out and look southeast about 45 minutes before the sun begins to rise. On April 23rd, the Moon will appear in conjunction with the other spheres, appearing to the right and above Saturn, before moving off again by April 29th. In mid-June, due to its rapid orbiting around...

Explanation: It is not a coincidence that planets line up. That's because all of the planets orbit the Sun in (nearly) a single sheet called the plane of the ecliptic. When viewed from inside that plane -- as Earth dwellers are likely to do -- the planets all appear confined to a single band. It is a coincidence, though, when three of the brightest planets all appear in nearly the same direction. Such a coincidence was captured earlier this month. Featured above (right to left), Venus, Saturn, and Jupiter were all imaged together in a line just after sunset, from...

A rare event in the heavens just ahead of Christmas will feature an alignment of planets that a famous astronomer believed was the phenomenon that is mentioned in the Bible when Jesus Christ was born. The alignment of Jupiter and Saturn will appear in the skies on December 21, the winter solstice. The last time the rare alignment of the planets was this close was in 1623, nearly 400 years ago. That was only 14 years after Galileo discovered the moons of Jupiter with the invention of the telescope. Another famous astronomer, Johannes Kepler, posited in 1614 that the alignment...

Explanation: What would make a moon look like a walnut? A strange ridge that circles Saturn's moon Iapetus's equator, visible near the bottom of the featured image, makes it appear similar to a popular edible nut. The origin of the ridge remains unknown, though, with hypotheses including ice that welled up from below, a ring that crashed down from above, and structure left over from its formation perhaps 100 million years ago. Also strange is that about half of Iapetus is so dark that it can nearly disappear when viewed from Earth, while the rest is, reflectively, quite bright. Observations...

Explanation: This is what Saturn looks like from inside the rings. In 2017, for the first time, NASA directed the Cassini spacecraft to swoop between Saturn and its rings. During the dive, the robotic spacecraft took hundreds of images showing unprecedented detail for structures in Saturn's atmosphere. Looking back out, however, the spacecraft was also able to capture impressive vistas. In the featured image, taken a few hours before closest approach, Saturn's unusual northern hexagon is seen surrounding the North Pole. Saturn's B ring is the closest visible, while the dark Cassini Division separates B from the outer A. A...

NASA James Webb Space Telescope Multilayered Sunshield In this illustration, the multilayered sunshield on NASA’s James Webb Space Telescope stretches out beneath the observatory’s honeycomb mirror. The sunshield is the first step in cooling down Webb’s infrared instruments, but the Mid-Infrared Instrument (MIRI) requires additional help to reach its operating temperature. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez The Mid-Infrared Instrument (MIRI) on NASA’s James Webb Space Telescope has four observational modes. After measuring increased friction in one of the grating wheels used in MIRI’s medium resolution spectrometry (MRS) mode, the Webb team paused science observations using this specific mode on August...

University of Arizona scientists have uncovered a curious case of missing asteroids. The main asteroid belt is a zone containing millions of rocky objects between the orbits of Mars and Jupiter. The scientists find that there ought to be more asteroids there than researchers observe. The missing asteroids may be evidence of an event that took place about 4 billion years ago, when the solar system's giant planets migrated to their present locations. UA planetary sciences graduate student David A. Minton and UA planetary sciences professor Renu Malhotra say missing asteroids is an important piece of evidence to support an...

This is an artist's concept of a hypothetical 10-million-year-old star system. The bright blur at the center is a star much like our sun. The other orb in the image is a gas-giant planet like Jupiter. Wisps of white throughout the image represent traces of gas. Astronomers using NASA's Spitzer Space Telescope have found evidence showing that gas-giant planets either form within the first 10 million years of a sun-like star's life, or not at all. The lifespan for sun-like stars is about 10 billion years. The scientists came to this conclusion after searching for traces of gas around...

Jupiter, the biggest planet in the solar system, might have gained its dominant position after swallowing up a smaller planet, scientists believe. Studies on Jupiter have revealed that the giant planet, which is more than 120 times bigger than the Earth, has an extremely small core that weighs just two to 10 Earth masses. Now scientists have claimed that Jupiter's core might have been vaporised in huge collision with a planet up to ten times the size of Earth, the New Scientist reported. Researchers led by by Shu Lin Li of Peking University in China have modelled what might have...

JANUARY 17, 2015 Ted Cruz and the Ice Giants Senator Ted Cruz now oversees NASA, and that’s a very good thing.By Josh Gelernter Neptune, photographed by Voyager 2 in 1989. (NASA)With the GOP in charge of the Senate, Ted Cruz has taken charge of the Science, Space, and Competitiveness subcommittee. Which means Ted Cruz now oversees NASA. On Wednesday, Cruz issued a statement saying that “Our space program marks the frontier of future technologies for defense, communications, transportation and more, and our mindset should be focused on NASA’s primary mission: exploring space and developing the wealth of new technologies that...

Left: mosaic of the incidence-angle-corrected SAR swaths within the ROI. Right: geomorphological map of the ROI. Credit: The Planetary Science Journal (2022). DOI: 10.3847/PSJ/ac8428 When NASA's 990-pound Dragonfly rotorcraft reaches the Selk crater region—the mission's target touchdown spot—on Saturn's moon Titan in 2034, Cornell's Léa Bonnefoy will have helped to make it a smooth landing. Bonnefoy and her colleagues assisted the future arrival by characterizing the equatorial, hummocky, knoll-like landscape by combining and analyzing all of the radar images of the area acquired by the Cassini spacecraft during its historic 13 year exploration of the Saturn system. They used radar...

One of Jupiter's tenuous rings can be seen in this infrared image. (NASA/ESA/CSA/STScI/Judy Schmidt) Given its similarities to its neighbor, Saturn, it seems natural to ask why Jupiter doesn't also have a magnificent, extensive system of visible rings. Alas, it's not the reality. While Jupiter does have rings, they're thin, tenuous, flimsy things of dust, visible only when back-lit by the Sun. According to new research, these discount rings lack bling because Jupiter's posse of chonky Galilean moons keep discs of rock and dust from accumulating the way they do around Saturn. "It's long bothered me why Jupiter doesn't have...

The month starts off with three bright planets clustered low in our east-southeast sky just before sunrise. Venus, Saturn and Mars are within six degrees of separation, but each morning thereafter the configuration noticeably changes. Mars and Saturn approach each other more closely than the apparent diameter of the moon on April 5. A view of the predawn sky on April 19, 2022 in Stellarium shows the alignment of Jupiter, Venus, Mars and Saturn. (Image credit: Stellarium) The main event comes during the final week of April with the approach of magnitude -2 Jupiter to magnitude -4 Venus, seven times...

Explanation: Why would the surface of Titan light up with a blinding flash? The reason: a sunglint from liquid seas. Saturn's moon Titan has numerous smooth lakes of methane that, when the angle is right, reflect sunlight as if they were mirrors. Pictured here in false-color, the robotic Cassini spacecraft that orbited Saturn from 2004 to 2017 imaged the cloud-covered Titan in 2014 in different bands of cloud-piercing infrared light. This specular reflection was so bright it saturated one of Cassini's infrared cameras. Although the sunglint was annoying -- it was also useful. The reflecting regions confirm that northern Titan...

Explanation: Seen from ice moon Tethys, rings and shadows would display fantastic views of the Saturnian system. Haven't dropped in on Tethys lately? Then this gorgeous ringscape from the Cassini spacecraft will have to do for now. Caught in sunlight just below and left of picture center in 2005, Tethys itself is about 1,000 kilometers in diameter and orbits not quite five saturn-radii from the center of the gas giant planet. At that distance (around 300,000 kilometers) it is well outside Saturn's main bright rings, but Tethys is still one of five major moons that find themselves within the boundaries...

Jupiter, Saturn and Venus have lined up in the evening sky and will continue to be prominent features throughout most of December, but this week, the trio will get a visitor. The easy-to-find planets, paired with the approaching peak of the Geminid meteor shower, make December a great month for evening stargazing. The only caveat is that the weather can be fickle during the long December nights, often offering frosty conditions on nights that are not cloudy. The moon started off the week next to Venus, and as the week progresses, it will continue to move up the chain, passing...

Composite image of Neptune, Uranus, Saturn and Jupiter. Credit: Jupiter from Juno: NASA/SwRI/MSSS/Gerald Eichstädt/Seán Doran; Saturn from Cassini: NASA/JPL-Caltech/Space Science Institute; Uranus and Neptune from HST: NASA/ESA/A. Simon (NASA Goddard Space Flight Center), and M.H. Wong and A. Hsu (University of California, Berkeley). ========================================================================================== Mushballs – giant, slushy hailstones made from a mixture of ammonia and water – may be responsible for an atmospheric anomaly at Neptune and Uranus that has been puzzling scientists. A study presented by Tristan Guillot at the Europlanet Science Congress (EPSC) 2021 shows that mushballs could be highly effective at carrying ammonia deep into the...