Potential sign of alien life detected on inhospitable Venus

By Will Dunham

WASHINGTON (Reuters) – Scientists said on Monday they have detected in the harshly acidic clouds of Venus a gas called phosphine that indicates microbes may inhabit Earth’s inhospitable neighbor, a tantalizing sign of potential life beyond Earth.

The researchers did not discover actual life forms, but noted that on Earth phosphine is produced by bacteria thriving in oxygen-starved environments. The international scientific team first spotted the phosphine using the James Clerk Maxwell Telescope in Hawaii and confirmed it using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in Chile.

“I was very surprised – stunned, in fact,” said astronomer Jane Greaves of Cardiff University in Wales, lead author of the research published in the journal Nature Astronomy.

The existence of extraterrestrial life long has been one of the paramount questions of science. Scientists have used probes and telescopes to seek “biosignatures” – indirect signs of life – on other planets and moons in our solar system and beyond.

“With what we currently know of Venus, the most plausible explanation for phosphine, as fantastical as it might sound, is life,” said Massachusetts Institute of Technology molecular astrophysicist and study co-author Clara Sousa-Silva.

“I should emphasize that life, as an explanation for our discovery, should be, as always, the last resort,” Sousa-Silva added. “This is important because, if it is phosphine, and if it is life, it means that we are not alone. It also means that life itself must be very common, and there must be many other inhabited planets throughout our galaxy.”

Phosphine – a phosphorus atom with three hydrogen atoms attached – is highly toxic to people.

Earth-based telescopes like those used in this research help scientists study the chemistry and other characteristics of celestial objects.

Phosphine was seen at 20 parts-per-billion in the Venusian atmosphere, a trace concentration. Greaves said the researchers examined potential non-biological sources such as volcanism, meteorites, lightning and various types of chemical reactions, but none appeared viable. The research continues to either confirm the presence of life or find an alternative explanation.

Venus is Earth’s closest planetary neighbor. Similar in structure but slightly smaller than Earth, it is the second planet from the sun. Earth is the third. Venus is wrapped in a thick, toxic atmosphere that traps in heat. Surface temperatures reach a scorching 880 degrees Fahrenheit (471 degrees Celsius), hot enough to melt lead.

“I can only speculate on what life might survive on Venus, if indeed it is there. No life would be able to survive on the surface of Venus, because it is completely inhospitable, even for biochemistries completely different from ours,” Sousa-Silva said. “But a long time ago, Venus could have had life on its surface, before a runaway greenhouse effect left the majority of the planet completely uninhabitable.”

THE ACID TEST

Some scientists have suspected that the Venusian high clouds, with mild temperatures around 86 degrees Fahrenheit (30 degrees Celsius), could harbor aerial microbes that could endure extreme acidity. These clouds are around 90% sulfuric acid. Earth microbes could not survive that acidity.

“If it’s microorganisms, they would have access to some sunlight and water, and maybe live in liquid droplets to stop themselves dehydrating, but they would need some unknown mechanism to protect against corrosion by acid,” Greaves said.

On Earth, microorganisms in “anaerobic” environments – ecosystems that do not rely on oxygen – produce phosphine. These include sewage plants, swamps, rice fields, marshlands, lake sediments and the excrements and intestinal tracts of many animals. Phosphine also arises non-biologically in certain industrial settings.

To produce phosphine, Earth bacteria take up phosphate from minerals or biological material and add hydrogen.

“We have done our very best to explain this discovery without the need for a biological process. With our current knowledge of phosphine, and Venus, and geochemistry, we cannot explain the presence of phosphine in the clouds of Venus. That doesn’t mean it is life. It just means that some exotic process is producing phosphine, and our understanding of Venus needs work,” Clara Sousa-Silva said.

Venus should be hostile to phosphine. Its surface and atmosphere are rich in oxygen compounds that would rapidly react with and destroy phosphine.

“Something must be creating the phosphine on Venus as fast as it is being destroyed,” said study co-author Anita Richards, an astrophysicist associated with the University of Manchester in England.

While previous robotic spacecraft have visited Venus, a new probe may be needed to confirm life.

“Fortunately, Venus is right next door,” Sousa-Silva said. “So we can literally go and check.”

(Reporting by Will Dunham; Editing by Daniel Wallis)

Interstellar gatecrasher 2I/Borisov is no ordinary comet

By Will Dunham

WASHINGTON (Reuters) – Scientists have discovered that a comet called 2I/Borisov – only the second interstellar object ever detected passing through the solar system – is surprisingly different in its composition from comets hailing from our celestial neighborhood.

Gas coming off 2I/Borisov contained high amounts of carbon monoxide – far more than comets formed in our solar system – indicating the object had large concentrations of carbon monoxide ice, researchers said on Monday.

Carbon monoxide, poisonous to humans, is common as a gas in space and forms as ice only in the most frigid locations. The presence of so much carbon monoxide, the researchers said, suggests 2I/Borisov formed in a different manner than comets in our solar system – in a very cold outer region of its home star system or around a star cooler than the sun.

Comets essentially are dirty snowballs composed of frozen gases, rock and dust that orbit stars.

“We like to refer to 2I/Borisov as a snowman from a dark and cold place,” said planetary scientist Dennis Bodewits of Auburn University in Alabama, lead author of one of two 2I/Borisov studies published in the journal Nature Astronomy.

“Comets are left-over building blocks from the time of planet formation. For the first time, we have been able to measure the chemical composition of such a building block from another planetary system while it flew through our own solar system,” Bodewits added.

The comet, detected in August 2019 by amateur astronomer Gennady Borisov and estimated to be about six-tenths of a mile (1-km) wide, has zoomed through interstellar space after being ejected from its original star system.

It was born long ago in a rotating disc of gas and dust surrounding a newly formed star in a place that must have been rich in carbon monoxide, Bodewits said. That star may have been what is called an M-dwarf, far smaller and cooler than the sun and the smallest type of star that is known, Bodewits said.

Scientists initially concluded last year that 2I/Borisov was similar to comets from our solar system, but data from the Hubble Space Telescope and an observatory in Chile revealed its differences.

The researchers also found an abundance of hydrogen cyanide at levels similar to comets from our solar system.

“This shows that 2I/Borisov is not a completely alien object, and confirms some similarity with our ‘normal’ comets, so the processes that shaped it are comparable to the way our own comets formed,” said Martin Cordiner, an astrobiologist working at NASA’s Goddard Space Flight Center in Maryland and lead author of the other study.

The only other interstellar visitor discovered in our solar system was a cigar-shaped rocky object called ‘Oumuamua spotted in 2017.

(Reporting by Will Dunham; Editing by Sandra Maler)

Planetary ‘autopsies’ indicate worlds like Earth common in the cosmos

Planetary ‘autopsies’ indicate worlds like Earth common in the cosmos
By Will Dunham

WASHINGTON (Reuters) – A new way of studying planets in other solar systems – by doing sort of an autopsy on planetary wreckage devoured by a type of star called a white dwarf – is showing that rocky worlds with geochemistry similar to Earth may be quite common in the cosmos.

In a study published on Thursday, researchers studied six white dwarfs whose strong gravitational pull had sucked in shredded remnants of planets and other rocky bodies that had been in orbit. This material, they found, was very much like that present in rocky planets such as Earth and Mars in our solar system.

Given that Earth harbors an abundance of life, the findings offer the latest tantalizing evidence that planets similarly capable of hosting life exist in large numbers beyond our solar system.

“The more we find commonalities between planets made in our solar system and those around other stars, the more the odds are enhanced that the Earth is not unusual,” said Edward Young, a geochemistry and cosmochemistry professor at the University of California, Los Angeles (UCLA), who helped lead the study published in the journal Science. “The more Earth-like planets, the greater the odds for life as we understand it.”

The first planets beyond our solar system, called exoplanets, were spotted in the 1990s, but it has been tough for scientists to determine their composition. Studying white dwarfs offered a new avenue.

A white dwarf is the burned-out core of a sun-like star. In its death throes, the star blows off its outer layer and the rest collapses, forming an extremely dense and relatively small entity that represents one of the universe’s densest forms of matter, exceeded only by neutron stars and black holes.

Planets and other objects that once orbited it can be ejected into interstellar space. But if they stray near its immense gravitation field, they “will be shredded into dust, and that dust will begin to fall onto the star and sink out of sight,” said study lead author Alexandra Doyle, a UCLA graduate student in geochemistry and astrochemistry.

“This is where that ‘autopsy’ idea comes from,” Doyle added, noting that by observing the elements from the massacred planets and other objects inside the white dwarf scientists can understand their composition.

The researchers observed a fundamental characteristic of the rocks: their state of oxidation. The amount of oxygen present during the formation of these rocks was high – just as it was during the formation of our solar system’s rocky material. They focused on iron, which when oxidized ends up as rock.

“Rocks are rocks, even when they form around other stars,” Young said.

The closest of the six white dwarf stars is about 200 light-years from Earth. The farthest is about 665 light-years away.

(Reporting by Will Dunham; Editing by Sandra Maler)

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)