Tag Archives: Solar System

Cigar-shaped interstellar visitor ‘Oumuamua classified as comet

This artist’s impression shows the first interstellar asteroid, `Oumuamua as it passes through the solar system after its discovery in October 2017. European Southern Obervatory/M. Kornmesser/Handout via REUTERS

By Will Dunham

WASHINGTON (Reuters) – The reddish cigar-shaped object called ‘Oumuamua spotted last year tumbling through space is a comet, scientists said on Wednesday, solving the mystery over how to classify the first interstellar object found passing through our solar system.

Astronomers said they closely examined the trajectory of ‘Oumuamua, which measures about a half-mile (800 meters) long, as it speeds through our cosmic neighborhood after being evicted somehow from a distant star system.

They found that it is deviating slightly from a path that would be explained purely by the Sun’s gravitational pull because of what apparently is a very small emission of gas from its surface, indicative of a comet.

‘Oumuamua (pronounced oh-MOO-uh-MOO-uh) initially was pegged as a comet, but it lacks the tail of gas and dust characteristic of many comets, and some scientists argued that it was perhaps a dry asteroid.

“It does not display any tail in any observation we obtained,” said astronomer Marco Micheli of the European Space Agency’s SSA-NEO Coordination Centre in Italy, who led the study, published in the journal Nature.

“However, our analysis shows that the amount of emitted gas that is needed to generate this extra force we see would have been so small as to be invisible in our observations,” he said in an email.

This “extra force” acting on the object’s trajectory amounts to only about 0.1 percent of the Sun’s gravitational attraction.

‘Oumuamua was first detected last October by the University of Hawaii’s Pan-STARRS1 telescope. Its name refers in the native Hawaiian language to a messenger arriving from a great distance.

It previously slingshot past the Sun traveling at roughly 196,000 miles per hour (315,000 km per hour) and is heading out of the solar system in the direction of the constellation Pegasus. ‘Oumuamua as of last month was roughly the same distance from the Sun as Jupiter.

Astronomers suspect that more visitors from other star systems will be discovered passing through our solar system.

“The discovery of ‘Oumuamua is an absolute first in the field, and it provided our first opportunity to study an object coming from another star and planetary system,” Micheli said. “The existence of these objects was expected, but seeing one for the first time, and being able to study it in detail, is a unique chance to know more on these distant systems, and how they formed.”

(Reporting by Will Dunham; Editing by Steve Orlofsky)

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)

Researchers find possible ninth planet beyond Neptune

CAPE CANAVERAL, Fla. (Reuters) – The solar system may host a ninth planet that is about 10 times bigger than Earth and orbiting far beyond Neptune, according to research published on Wednesday.

Computer simulations show that the mystery planet, if it exists, would orbit about 20 times farther away from the sun than Earth, said astronomers with the California Institute of Technology in Pasadena.

So far, the planet has not been observed directly.

“It’s a pretty substantial chunk of our solar system that’s still out there to be found, which is pretty exciting,” said astronomer Mike Brown, whose discovery was published in this week’s Astronomical Journal.

Brown and astronomer Konstantin Batygin, also at Caltech, initially were skeptical that such a large planet would have eluded detection.

But they modeled the hypothetical planet’s gravitational effects on several known bodies in the region and found a near-perfect match.

The computer model also predicted the location of other objects beyond Neptune, in a region known as the Kuiper Belt, and those were found in archived surveys as well.

At that point, “my jaw sort of hit the floor,” Brown said in a statement.

Brown’s earlier research helped to demote Pluto in 2006 as the solar system’s ninth planet after other small, icy bodies were found beyond Neptune.

“All those people who are mad that Pluto is no longer a planet can be thrilled to know that there is a real planet out there still to be found,” Brown said.

(Reporting by Irene Klotz; editing by Bill Trott, Letitia Stein and Dan Grebler)