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Uranus smells like farts, astronomers have confirmed — and the discovery indicates there was ‘a big shakeup’ early in the solar system

A photo of Uranus taken by Voyager 2 in 1986 (edited to show its moon and rings).NASA/JPL-Caltech

  • Uranus is one of the solar system’s most mysterious planets.
  • Scientists had long believed that the “ice giant” world has clouds of hydrogen sulfide, a compound that smells bad to people, but they couldn’t be certain.
  • New telescope observations confirm the planet is clouded by the chemical.
  • The discovery may help astronomers further unravel the twisted history of the solar system‘s formation.

Uranus, the seventh planet from the sun, has held a vital (and smelly) secret of the solar system for decades.

An international team of researchers reported on Monday that they’ve discovered evidence that Uranus holds one of the most unpleasant-smelling chemicals known to humankind.

“They found hydrogen sulfide, the odiferous gas that most people avoid, in Uranus’s cloud tops,” according to a press release from Gemini Observatory, a high-power telescope atop a Hawaiian volcano.

Voyager 2 was the only spacecraft ever to visit the chilly, blue-green “ice giant.” The probe tried to see which chemicals were in Uranus’ clouds during its 1986 flyby, but it couldn’t tell scientists for certain.

Now, however, astronomers have used an instrument at the Gemini Observatory to “sniff” the planet’s gases from Earth. Their discovery could help write the book on when and where the planets of the solar system formed — and if they ever switched places.

“This is evidence of a big shakeup early on in the solar system’s formation,” Glenn Orton, a co-author of the new study and a planetary scientist at NASA’s Jet Propulsion Laboratory, told Business Insider. “There was definitely a migration taking place.”

The journal Nature Astronomy published the findings on Monday.

Why it took so long to detect Uranus’s stinky clouds

The reason most people avoid hydrogen sulfide is because the compound is a signature ingredient in the scent of rotten eggs — and farts.

Humans can smell hydrogen sulfide when it makes up as little as three out of every billion molecules in the air, the EPA says. At higher concentrations, such as near volcanic areas, it can be poisonous. Breathing a concentration of a few hundred parts per million can kill a person in about half an hour, according to the Centers for Disease Control.

“If an unfortunate human were ever to descend through Uranus’s clouds, they would be met with very unpleasant and odiferous conditions,” Patrick Irwin, a physicist at the University of Oxford who led the new study, said in the press release. But he added that “suffocation and exposure” to Uranus’ -200 degree Celsius temperatures “would take its toll long before the smell.”

Researchers had long suspected that Uranus’s atmosphere was laced with hydrogen sulfide, and in concentrations dozens of times higher than at Saturn or Jupiter.

They couldn’t be certain, though, since Uranus orbits the sun from 1.85 billion miles away.

The vast distance, aside from making the planet distant and difficult to study, leads to blisteringly cold temperatures that freezes hydrogen sulfide. Hydrogen-sulfide ice can form clouds, but the solid crystals are hard for chemical-analyzing instruments called spectrometers to study. (The method works far better with liquids and gases.)

Irwin and others suspected there were at least whiffs of hydrogen sulfide gas drifting above the clouds. And now, thanks to an extremely sensitive Gemini instrument that can see light invisible to humans, Irwin said scientists “have the fingerprint which caught the culprit.”

Why the discovery might ‘shake up’ ideas about the solar system’s evolution

An artist’s conception of the dust and gas surrounding a newly formed planetary system.

Astronomers like Irwin have an interest in hydrogen sulfide on Uranus that goes far beyond the gas’ smell.

The discovery of hydrogen sulfide may help piece together the story of how the solar system formed and arranged itself some 4.6 billion years ago. Figuring out the exact makeup of distant planets could help determine where in the solar system they first formed — and how far they migrated away from the sun afterward.

Like all planets, Uranus and Neptune formed from a giant disk of gas and dust that shrouded the sun some 4.6 billion years ago. The planets are mostly made of heavier elements, and didn’t balloon with lightweight hydrogen and helium gases.

“Uranus and Neptune never had the time to grow into gas giants like Jupiter and Saturn,” Imke de Pater, an astronomer at the University of California Berkeley who wasn’t involved in the study, wrote in an accompanying article in Nature Astronomy. “The composition of a celestial body is a fundamental parameter in determining its formation and evolutionary history.”

The two planets failed to become gas giants (and instead became “ice giants”) for two main reasons.

First, the solar system’s early disk of dust and gas grew more diffuse farther out from the sun. With less material available, it took Uranus and Neptune longer to form.

Second, this slower formation gave the sun more time to blow hydrogen and helium out of the solar system with its stellar winds— before Uranus and Neptune could grow massive enough to capture it with their gravity.

“Giant planets form really fast, in a few million years,” Kevin Walsh, who studies planet formation at the Southwest Research Institute in Colorado, told Space.com in March. “That creates a time limit because the gas disk around the sun only lasts 4 to 5 million years.”

Scientists agree on this much, but Orton said they have “too many theories” about the migration of Uranus and Neptune, which came next.

A true-color photo of Uranus (left) and a false color image (right) taken at the turn of 1986 by NASA’s Voyager 2 probe.

One leading idea says the planets coalesced millions of miles closer to the sun, then quickly migrated outward.

But Orton said the newly detected hydrogen sulfide — and a strange lack of ammonia in the Gemini Observatory readings — suggest the planets actually formed farther out, then moved inward. (The ratio of the two molecules suggests the worlds were once even colder than they are today.)

To solve the question once and for all, Orton says researchers need to send spacecraft to plunge through the clouds of Uranus, not unlike how the Cassini probe dove into Saturn. The goal: figure out the exact abundances of hydrogen sulfide and ammonia, among other gases, and use the readings to pin the exact birth locations of Uranus and Neptune.

“We’re working on that now,” Orton said, referring to a proposal for a new Uranus probe.

Source www.businessinsider.com

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Our Galaxy’s Black Hole Suddenly Lit Up and Nobody Knows Why

In May, the supermassive black hole at the core of the Milky Way became 75 times brighter in just two hours.

The supermassive black hole that lives at the center of our galaxy has been mysteriously sparkling as of late, and nobody knows the reason.

This dark behemoth, known as as Sagittarius A* (Sgr A*), is four million times as massive as the Sun. Though no light escapes its boundaries, astronomers can observe the hole’s interactions with bright stars or dust clouds that surround it.

On the night of May 13, 2019, UCLA astronomer Tuan Do and his colleagues were watching Sgr A* using the Keck Telescope on the summit of Mauna Kea in Hawai’i. In a period of just two hours, they witnessed the black hole become 75 times brighter in the near-infrared band of the light spectrum.

That spring evening, the Milky Way’s supermassive black hole “reached much brighter flux levels in 2019 than ever measured at near-infrared wavelengths,” according to a forthcoming studyled by Do and published on the arXiv preprint server.

“The brightness of Sgr A* varies all the time, getting brighter and fainter on the timescale of minutes to hours—it basically flickers like a candle,” Do said in an email. “We think that something unusual might be happening this year because the black hole seems to vary in brightness more, reaching brighter levels than we’ve ever seen in the past.”

The peak flux, meaning the most luminous phase of the flare-up, soared to “twice the maximum historical flux measurements,” Do’s team said in the study. In other words, in the 20 years since astronomers have monitored Sgr A*, the next-brightest event has only been half as dazzling as this one.

This unusual sparkle at the galactic core was likely caused by close encounters between Sgr A* and objects surrounding it, according to the team.

The edge of a black hole, called an event horizon, is shaped by intense tidal forces that tear at anything that gets close. Once a black hole starts devouring nearby objects like stars or gas clouds, infalling material heats up at the event horizon, sparking light shows that can be picked up by telescopes.

Do and his colleagues speculate that a star called S0-2, which is about 15 times as massive as the Sun, may have been the object that juiced Sgr A*. In 2018, S0-2 came within 17 light hours of the supermassive black hole, and that close pass may have disturbed gases at the event horizon enough to cause the May 2019 brightening event.

This composite image shows the motion of the dusty cloud G2 as it closes in on, and then passes, the supermassive black hole at the centre of the Milky Way. These new observations with ESO’s VLT have shown that the cloud appears to have survived its close encounter with the black hole and remains a compact object that is not significantly extended. In this image the position of the cloud in the years 2006, 2010, 2012 and February and September 2014 are shown, from left to right. The blobs have been colourised to show the motion of the cloud, red indicated that the object is receding and blue approaching. The cross marks the position of the supermassive black hole.

Another possible culprit is a dust cloud known as G2, which passed about 36 light hours from Sgr A* in 2014. Scientists predicted that G2 would be torn apart by the hole, but the results were ultimately described as disappointing and “boring” for astronomers.

That initial letdown may have been premature, though, because we might be seeing the slow-burn “delayed reaction” to the gas cloud’s approach, the team said.

“Many astronomers are observing Sgr A* this summer,” Do noted. “I’m hoping we can get as much data as we can this year before the region of the sky with Sgr A* gets behind the Sun and we won’t be able to observe it again until next year.”

“Maybe the black hole is waking up—there’s a lot we don’t know at this point so we need more data to understand if what we are seeing is a big change in what is feeding the black hole or this is a brief event,” he said.

Source www.vice.com

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Milky Way galaxy is warped and twisted, not flat

Our galaxy, the Milky Way, is “warped and twisted” and not flat as previously thought, new research shows.

Analysis of the brightest stars in the galaxy shows that they do not lie on a flat plane as shown in academic texts and popular science books.

Astronomers from Warsaw University speculate that it might have been bent out of shape by past interactions with nearby galaxies.

The new three dimensional map has been published in the journal Science.

The popular picture of the Milky Way as a flat disc is based on the observation of 2.5 million stars out of a possible 2.5 billion. The artists’ impressions are therefore rough approximations of the truer shape of our galaxy, according to Dr Dorota Skowron of Warsaw University.

“The internal structure and history of the Milky Way is still far from being understood, in part because it is extremely difficult to measure distances to stars at the outer regions of our galaxy,” she said.

To gain a more accurate picture, Dr Skowron and her colleagues measured the distances of some of the brightest stars in the Milky Way, called Cepheid variable stars. These are massive young stars that burn hundreds, if not thousands, of times brighter than our own Sun. They can be so bright that they can be observed at the very edge of the galaxy.

Not only that, they also pulsate at regular intervals at a rate that is directly related to their brightness.

Artists’ impressions which depict the Milky Way as a flat disk will have to be revised

This enables astronomers to calculate their distance with great precision.

Most of the stars were identified by the Optical Gravitational Lensing Experiment (OGLE) at Las Campanas Observatory (LCO) in Chile’s southern Atacama Desert. Przemek Mroz, a member of the OGLE team, said that the results were surprising.

Warsaw Telescope and Milky Way Cepheids discovered by the OGLE survey

“Our results show that the Milky Way Galaxy is not flat. It is warped and twisted far away from the galactic centre. Warping may have happened through past interactions with satellite galaxies, intergalactic gas or dark matter (invisible material present in galaxies about which little in known).”

The Polish results support an analysis of Cepheid variable stars published in February in Nature Astronomy journal by astronomers from Macquarie University in Australia and the Chinese Academy of Sciences.

Source www.bbc.co.uk

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SpaceX Starship update coming later this month

Image Credit: SpaceX / Elon Musk

Starship could carry the first astronauts back to the Moon.

Elon Musk’s private space firm has been developing a spacecraft capable of landing humans on other worlds.

Designed to serve as the reusable second stage of the Big Falcon Rocket (BFR), Starship will also be able to carry astronauts and cargo all the way to the surface of Mars.

The spacecraft has undergone several name changes since it was first announced, having previously transitioned from Mars Colonial Transporter (MCT) to Interplanetary Transport System (ITS).

Now Elon Musk has revealed that a full update on the project will be coming on August 24th at either Cape Canaveral in Florida or Boca Chica in Texas, which is where a prototype was recently tested.

Writing on Twitter, he stated that the update would include a “detailed review of the first orbital Starship, explaining the pros and cons of each design decision.”

“We should have Starship Mk1 with 3 Raptors almost ready to fly by then,” he said.

It will certainly be interesting to see how things are progressing.

Source: Ars Technica

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