‘Great Conjunction’: Earthlings treated to rare alignment of Jupiter and Saturn

By Peter Szekely

NEW YORK (Reuters) -The evening sky over the Northern Hemisphere treated stargazers to a once-in-a-lifetime illusion on Monday as the solar system’s two biggest planets appeared to meet in a celestial alignment that astronomers call the “Great Conjunction.”

The rare spectacle resulted from a near convergence of the orbits of Jupiter and Saturn that happened to coincide with Monday’s winter solstice, the shortest day of the year. For those able to observe the alignment in clear skies, the two frozen-gas spheres appeared closer and more vibrant – almost as a single point of light – than at any time in 800 years.

Jupiter – the brighter and larger of the pair – has been gradually nearing Saturn in the sky for weeks as the two planets proceed around the sun, each in its own lane of an enormous celestial racetrack, said Henry Throop, an astronomer at National Aeronautics and Space Administration headquarters in Washington.

“From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on Dec. 21,” Throop said in a statement last week.

At the point of convergence, Jupiter and Saturn appeared to be just one-tenth of a degree apart, roughly equivalent to the thickness of a dime held at arm’s length. In reality, of course, the planets remained hundreds of millions of miles apart, according to NASA.

A conjunction of the two planets takes place about once every 20 years. But the last time Jupiter and Saturn came as close together in the sky as on Monday was in 1623, an alignment that occurred during daylight and was thus not visible from most places on Earth.

The last visible great conjunction occurred long before telescopes were invented, in 1226, halfway through construction of the Notre Dame cathedral in Paris.

The heightened brightness of the two planets as they almost merge in the sky has invited the inevitable speculation about whether they formed the “Christmas star” that the New Testament describes as having guided the three wise men to the baby Jesus.

But astronomer Billy Teets, acting director of Vanderbilt University’s Dyer Observatory in Brentwood, Tennessee, said a Great Conjunction is only one of several possible explanations for the biblical phenomenon.

“I think that there is a lot of debate as to what that might have been,” Teets told WKRN-TV in Nashville in a recent interview.

Astronomers suggested that the best way to view Monday’s conjunction was by looking toward the southwest in an open area about an hour after sunset.

“Big telescopes don’t help that much, modest binoculars are perfect, and even the eyeball is okay for seeing that they are right together,” Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, wrote in an email to Reuters.

The next Great Conjunction between the two planets — though not nearly as close together — comes in November 2040. A closer alignment similar to Monday’s will be in March 2080, McDowell said, with the following close conjunction 337 years later in August 2417.

(Reporting by Peter Szekely in New York; Additional reporting by Joey Roulette in Washington; Editing by Lisa Shumaker and Sonya Hepinstall)

NASA’s Juno spacecraft strips Jupiter down to its underwear

An illustration depicting the U.S. space agency's Juno spacecraft in orbit above Jupiter's Great Red Spot. NASA/JPL-Caltech/Handout via REUTERS

By Will Dunham

WASHINGTON (Reuters) – The interior of Jupiter is just as intriguing as the planet’s dazzling surface, with a swirling mixture of liquid hydrogen and helium at its center, vast atmospheric jet streams and exotic gravitational properties, scientists said on Wednesday.

Data from NASA’s Juno spacecraft, orbiting the solar system’s largest planet since 2016, is providing researchers with what they called unprecedented insight into Jupiter’s internal dynamics and structure. Until now, scientists have had scant information about what lies below Jupiter’s thick red, brown, yellow and white clouds.

“Juno is designed to look beneath these clouds,” said planetary science professor Yohai Kaspi of the Weizmann Institute of Science in Israel, who led part of the research using Juno’s new measurements of Jupiter’s gravity.

“On Jupiter, a gaseous planet without a solid surface, we can only gather information from orbit,” added aerospace engineering professor Luciano Iess of Sapienza University of Rome, who also led part of the research.

Jupiter is a type of planet called a gas giant, as opposed to rocky planets like Earth and Mars, and its composition is 99 percent hydrogen and helium. Juno’s data showed that as you go deeper under the surface, Jupiter’s gas becomes ionized and eventually turns into a hot, dense metallic liquid.

Jupiter's Great Red Spot is shown in this photo taken July 10, 2017. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Sean Doran/Handout via REUTERS

Jupiter’s Great Red Spot is shown in this photo taken July 10, 2017. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Sean Doran/Handout via REUTERS

The scientists said Jupiter’s jet streams, related to the familiar stripes on its surface, plunge some 1,800 miles (3,000 km) below cloud level, and that its deep interior is comprised of a fluid hydrogen and helium mixture that rotates as if it were a solid body.

“The very center may contain a core made of high-pressure and high-temperature rocks and perhaps water, but it is believed to be fluid as well, not solid,” said planetary scientist Tristan Guillot of the Université Côte d’Azur in Nice, another of the research leaders.

Juno’s data showed a small but significant asymmetry between the gravitational field of Jupiter’s northern and southern hemispheres, driven by the immense jet streams. The deeper the jets streams go, the more mass they contain, exerting a strong effect on Jupiter’s gravitational field, Kaspi said.

Jupiter, the fifth planet from the sun, dwarfs the solar system’s other planets, measuring about 89,000 miles (143,000 km) in diameter at its equator, compared with Earth’s diameter of about 8,000 miles (12,750 km). It is big enough that 1,300 Earths could fit inside it.

The research was published in the journal Nature.

(Reporting by Will Dunham; Editing by Jonathan Oatis)

Hubble spots evidence of water plumes on Jupiter’s moon Europa

A composite image shows suspected plumes of water vapor erupting at the seven o'clock position off the limb of Jupiter's moon Europa in a NASA Hubble Space Telescope picture taken January 26, 2014 and released September 26, 2016.

By Irene Klotz

(Reuters) – Astronomers on Monday said they have spotted evidence of water vapor plumes rising from Jupiter’s moon Europa, a finding that might make it easier to learn whether life exists in the warm, salty ocean hidden beneath its icy surface.

The apparent plumes detected by the Hubble Space Telescope shoot about 125 miles (200 km) above Europa’s surface before, presumably, raining material back down onto the moon’s surface, NASA said.

Europa, considered one of the most promising candidates for life in the solar system beyond Earth, boasts a global ocean with twice as much water as in all of Earth’s seas hidden under a layer of extremely cold and hard ice of unknown thickness.

While drilling through the ice to test ocean water for signs of life would be a daunting task, sampling water from the plumes might be a simpler project.

“If the plumes are real, it potentially gives us easier access to the ocean below … without needing to drill into miles of ice,” said lead researcher Williams Sparks of the Space Telescope Science Institute in Greenbelt, Maryland.

Europa is about 1,900 miles (3,100 km) in diameter, slightly smaller than Earth’s moon. Among Jupiter’s four largest moons, Europa is the second closest to the biggest planet in the solar system.

The telescope observed the plumes three times in 2014, mostly around Europa’s southern polar region, scientists told a conference call with reporters.

On Earth, life is found everywhere where there is water, energy and nutrients, so scientists have a special interest in places elsewhere in the solar system, like Europa, with similar characteristics, said Paul Hertz, director of NASA’s astrophysics division.

The findings, which will be published in The Astrophysical Journal, follow an initial Hubble sighting of a water vapor plume over Europa’s south pole in December 2012.

Scientists got their first hint that bright, icy Europa, which is crisscrossed by dark bands and ridges, contains an underground ocean from NASA’s twin Voyager probes, which flew by Jupiter in 1979.

The follow-on Galileo spacecraft, which circled around and through Jupiter’s system from 1995 to 2003, detected a magnetic field that likely was triggered by a salty, global ocean beneath Europa’s surface.

Two more missions are in development to visit Europa.

A NASA spacecraft, targeted for launch in the mid-2020s, would make more than 40 close flybys of the moon and possibly sample material in any plumes shooting out from its surface.

Jupiter has 67 known moons, plus many smaller ones that have not yet been named.

(Reporting by Irene Klotz in Guadalajara, Mexico; Editing by Will Dunham)

Great Red Spot Storm heating Jupiter’s atmosphere

Jupiter's most distinctive feature - a giant red spot, is seen in this April 21, 2014, REUTERS/NASA, ESA,

By Irene Klotz

CAPE CANAVERAL, Fla. (Reuters) – Scientists have long wondered why Jupiter’s upper atmosphere has temperatures similar to those of Earth, even though the biggest planet in the solar system is five times farther away from the sun.

The answer may be The Great Red Spot, an enormous storm big enough to swallow three Earths that has been raging on Jupiter for at least three centuries, a study showed on Wednesday.

Using an infrared telescope at Hawaii’s Mauna Kea Observatory, scientists discovered that the upper atmosphere above the Great Red Spot – the largest storm in the solar system – is hundreds of degrees hotter than anywhere else on the planet.

It could be a coincidence or a major clue, said Boston University physicist James O’Donoghue, lead scientist of the study published in the journal Nature.

The storm spans 13,670 miles by 7,456 miles (22,000 km by 12,000 km) and is located in Jupiter’s lower atmosphere. The top of its clouds reach altitudes of about 31 miles (50 km).

By a process of elimination, the newly found hot spot must be heated from below, the study concluded.

The finding provides a strong link between Jupiter’s upper and lower atmosphere, though the exact process by which heat is transferred remains unknown. The most-likely energy source is acoustic waves that provide heat from below, the study said.

Scientists also are unsure why the storm is brick red, nor why it has changed color over time. In a 1900 report in the Seattle Post-Intelligencer, scientists described the oval storm as salmon pink. Recent images from the Hubble Space Telescope show it has become orange tinged and more circular.

Like a hurricane on Earth, the Spot’s center is relatively calm, but farther out winds reach 270 mph to 425 mph (430 kph to 680 kph). Because there is no land on Jupiter, which is made almost entirely of hydrogen and helium, the storm can never make landfall and dissipate.

“The Great Red Spot is like a wheel that’s wedged between two conveyor belts running in opposite directions,” said planetary scientist Glenn Orton, with NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

“One is adding momentum to it at the top, and another is adding momentum at the bottom. Together, they feed the vortex and essentially keep it alive.”

But the storm may not be alive much longer. It has been shrinking for the last 100 years, Orton said.

More information is expected from NASA’s Juno spacecraft, which arrived at Jupiter on July 4.

(Reporting by Irene Klotz; Editing by Daniel Wallis and Alan Crosby)

NASA’s Juno spacecraft loops into orbit around Jupiter

Jupiter

By Irene Klotz

CAPE CANAVERAL, Fla. (Reuters) – NASA’s Juno spacecraft capped a five-year journey to Jupiter late Monday with a do-or-die engine burn to sling itself into orbit, setting the stage for a 20-month dance around the biggest planet in the solar system to learn how and where it formed.

“We’re there. We’re in orbit. We conquered Jupiter,” lead mission scientist Scott Bolton, with the Southwest Research Institute in San Antonio, told reporters on Tuesday. “Now the fun begins.”

Juno will spend the next three months getting into position to begin studying what lies beneath Jupiter’s thick clouds and mapping the planet’s gargantuan magnetic fields.

Flying in egg-shaped orbits, each one lasting 14 days, Juno also will look for evidence that Jupiter has a dense inner core and measure how much water is in the atmosphere, a key yardstick for figuring out how far away from the sun the gas giant formed.

Jupiter’s origins, in turn, affected the development and position of the rest of the planets, including Earth and its fortuitous location conducive to the evolution of life.

“The question I’ve had my whole life that I’m hoping we get an answer to is ‘How’d we get here?’ That’s really pretty fundamental to me,” Bolton said.

Jupiter orbits five times farther from the sun than Earth, but it may have started out elsewhere and migrated, jostling its smaller sibling planets as it moved.

Jupiter’s immense gravity also diverts many asteroids and comets from potentially catastrophic collisions with Earth and the rest of the inner solar system.

Launched from Florida nearly five years ago, Juno needed to be precisely positioned, ignite its main engine at exactly the right time and keep it firing for 35 minutes to become only the second spacecraft to orbit Jupiter.

If anything had gone even slightly awry, Juno would have sailed helplessly past Jupiter, unable to complete a $1 billion mission.

The risky maneuver began as planned at 11:18 p.m. EDT as Juno soared through the vacuum of space at more than 160,000 mph (257,500 kph).

NASA expects Juno to be in position for its first close-up images of Jupiter on Aug. 27, the same day its science instruments are turned on for a test run.

Only one other spacecraft, Galileo, has ever circled Jupiter, which is itself orbited by 67 known moons. Bolton said Juno is likely to discover even more.

Seven other U.S. space probes have sailed past the gas giant on brief reconnaissance missions before heading elsewhere in the solar system.

The risks to the spacecraft are not over. Juno will fly in highly elliptical orbits that will pass within 3,000 miles (4,800 km) of the tops of Jupiter’s clouds and inside the planet’s powerful radiation belts.

Juno’s computers and sensitive science instruments are housed in a 400-pound (180-kg) titanium vault for protection. But during its 37 orbits around Jupiter, Juno will be exposed to the equivalent of 100 million dental X-rays, said Bill McAlpine, radiation control manager for the mission.

The spacecraft, built by Lockheed Martin, is expected to last for 20 months. On its final orbit, Juno will dive into Jupiter’s atmosphere, where it will be crushed and vaporized.

Like Galileo, which circled Jupiter for eight years before crashing into the planet in 2003, Juno’s demise is designed to prevent any hitchhiking microbes from Earth from inadvertently contaminating Jupiter’s ocean-bearing moon Europa, a target of future study for extraterrestrial life.

(Editing by Kim Coghill and Andrew Heavens)

NASA’s Juno spacecraft poised for one-shot try to orbit Jupiter

NASA's Juno spacecraft obtained this color view at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter

By Irene Klotz

CAPE CANAVERAL, Fla. (Reuters) – A NASA spacecraft was poised for a one-shot attempt to slip into Jupiter’s orbit on Monday for the start of a 20-month-long dance around the solar system’s largest planet to learn how and where it formed.

Flight controllers at NASA’s Jet Propulsion Laboratory in Pasadena, California, were preparing for a long night as the Juno probe streaked closer toward Jupiter at 200 times the speed of sound in the empty vacuum of space.

Confirmation of whether Juno, the only solar-powered spacecraft ever dispatched to the outer solar system, had successfully placed itself into polar orbit around Jupiter was not expected until 11:53 p.m. EDT on Monday (0353 GMT on Tuesday).

Launched from Florida nearly five years ago, Juno must be precisely positioned, ignite its main engine at exactly the right time and keep it burning for 35 minutes to shed enough speed so it can be captured by Jupiter’s gravity.

If anything goes even slightly awry, Juno will sail helplessly past Jupiter, unable to complete a $1 billion mission to peer through the planet’s thick atmosphere and map its gargantuan magnetic field.

Scientists are particularly interested in learning how much water Jupiter contains, which is key to determining where in the solar system it formed. Jupiter’s origins, in turn, affected the development and position of the rest of the planets, including Earth and its fortuitous location conducive to the evolution of life.

The immense gravity exerted by Jupiter’s sheer size – packing 2-1/2 times the mass of all the other planets combined – is thought to have helped shield Earth from bombardment by comets and asteroids.

“We are learning about nature, how Jupiter formed and what that tells us about our history and where we came from,” Juno lead scientist Scott Bolton, with the Southwest Research Institute in San Antonio, told reporters.

‘MUSICAL NOTES’

Only one other spacecraft, Galileo, has ever circled Jupiter, which is five times farther away from the sun than Earth and is itself orbited by 67 known moons. Seven other U.S. space probes have sailed past the gas giant on brief reconnaissance missions before heading elsewhere in the solar system.

Ground control teams will monitor Juno’s progress during its do-or-die engine burn by listening for a series of radio signals.

“They really are musical notes. Based on what musical note is sent, we will know how something is doing,” Bolton said.

The risks to Juno will not end once it arrives in orbit. The probe will fly in highly elliptical, egg-shaped orbits that pass within 3,000 miles (4,800 km) of the tops of Jupiter’s clouds and inside the planet’s powerful radiation belts.

Juno’s sensitive science instruments are housed in a 400-pound (180-kg) titanium vault for protection. But during its 37 orbits around Jupiter, Juno will be exposed to the equivalent of 100 million dental X-rays, said Bill McAlpine, radiation control manager for the mission.

The spacecraft, built by Lockheed Martin, is expected to last for 20 months. On its final orbit, Juno will dive into Jupiter’s atmosphere, where it will be crushed and vaporized.

Like Galileo, which circled Jupiter for eight years before crashing into the planet in 2003, Juno’s demise is designed to prevent any hitchhiking microbes from Earth from inadvertently contaminating Jupiter’s ocean-bearing moon Europa, a target of future study for extraterrestrial life.

(Editing by Steve Gorman and Peter Cooney)

Five planets visible in pre-dawn sky for first time in 11 years

Early-morning stargazers will have the rare opportunity to observe five planets at the same time during the next few weeks, according to a recent post on astronomy website EarthSky.org.

EarthSky says it’s the first time in more than 11 years that the five brightest planets — Mercury, Venus, Mars, Jupiter and Saturn — will simultaneously appear in the sky above Earth.

People had their first chance to catch the five planets before sunrise this morning, according to EarthSky, and the rare sight can be witnessed just before dawn every day through February 20.

The planets can be seen without a telescope or binoculars from anywhere on Earth, the EarthSky post says. Unclear skies could prevent some people from observing the spectacle on certain days.

Venus, Jupiter To Provide “Best Backyard Sky Show”

Astronomers around the world are preparing for a major galactic event tonight, when Venus and Jupiter will cross paths in the night sky.

“To the eye they’ll look like a double star,” Sky & Telescope editor Kelly Beatty said on the magazine’s website.

Some of the astronomers say that the convergence of the two planets is so bright and noticeable that it could have been the “star of Bethlehem” that is mentioned in the Bible.  The planets will be a “jaw-dropping one-third of a degree apart” according to NASA.

“You’ll be able to hide the pair not just behind the palm of your outstretched hand, but behind your little pinky finger,” NASA says.

NASA says the convergence of the planets takes place about every 13 months.  However, it’s rare that the planets will come so close together in the night sky.  The next time the planets will be this close will be November 2065 when they will appear to cross paths.