Tag Archives: Nature

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)

Giant iceberg breaks off Antarctica

FILE PHOTO: An aerial view of the rift in the Larsen C seen in an image from the Digital Mapping System over the Antarctica Peninsula, Antarctica, on November 10, 2016. NASA's Goddard Space Flight Center/Handout via REUTERS/File Photo ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY

By Nina Chestney

LONDON (Reuters) – One of the biggest icebergs on record has broken away from Antarctica, scientists said on Wednesday, creating an extra hazard for ships around the continent as it breaks up.

The one trillion tonne iceberg, measuring 5,800 square km, calved away from the Larsen C Ice Shelf in Antarctica sometime between July 10 and 12, said scientists at the University of Swansea and the British Antarctic Survey.

The iceberg has been close to breaking off for a few months. Throughout the Antarctic winter, scientists monitored the progress of the rift in the ice shelf using the European Space Agency satellites.

“The iceberg is one of the largest recorded and its future progress is difficult to predict,” said Adrian Luckman, professor at Swansea University and lead investigator of Project MIDAS, which has been monitoring the ice shelf for years.

“It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters,” he added.

The ice will add to risks for ships now it has broken off. The peninsula is outside major trade routes but the main destination for cruise ships visiting from South America.

In 2009, more than 150 passengers and crew were evacuated after the MTV Explorer sank after striking an iceberg off the Antarctic peninsula.

The iceberg, which is likely to be named A68, was already floating before it broke away so there is no immediate impact on sea levels, but the calving has left the Larsen C ice shelf reduced in area by more than 12 percent.

The Larsen A and B ice shelves, which were situated further north on the Antarctic Peninsula, collapsed in 1995 and 2002, respectively.

“This resulted in the dramatic acceleration of the glaciers behind them, with larger volumes of ice entering the ocean and contributing to sea-level rise,” said David Vaughan, glaciologist and director of science at British Antarctic Survey.

“If Larsen C now starts to retreat significantly and eventually collapses, then we will see another contribution to sea level rise,” he added.

Big icebergs break off Antarctica naturally, meaning scientists are not linking the rift to manmade climate change. The ice, however, is a part of the Antarctic peninsula that has warmed fast in recent decades.

“In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse – opinions in the scientific community are divided,” Luckman said.

“Our models say it will be less stable, but any future collapse remains years or decades away.”

(Editing by Toby Chopra)