SACRAMENTO, Calif. — The trouble began when Anaheim resident Stephanie Jeffcoat lost her car in 2016. Forced to sleep in a tent and struggling with addiction, Jeffcoat found herself rapidly racking up tickets for various offenses — jaywalking, trespassing near railroad tracks, not having a bike light. The fines piled up: $80, $110, $55. Homeless and without a job, Jeffcoat couldn't afford to pay the fines. When she arrived to a court in 2017, a judge added a $300 fee for failing to pay. Two years later, her debt to Orange County Superior Court had grown to about $800, after another late fee wa...
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James Webb space telescope uncovers chemical secrets of distant world – paving the way for studying Earth-like planets
Since the first planet orbiting a star other than the Sun was discovered in 1995, we have realized that planets and planetary systems are more diverse than we ever imagined. Such distant worlds – exoplanets – give us the opportunity to study how planets behave in different situations. And learning about their atmospheres is a crucial piece of the puzzle.
Nasa’s James Webb space telescope (JWST) is the largest telescope in space. Launched on Christmas Day 2021, it is the perfect tool for investigating these worlds. Now my colleagues and I have used the telescope for the first time to unveil the chemical make-up of an exoplanet. And the data, released in preprint form (meaning it has yet to be published in a peer-reviewed journal), suggests some surprising results.
Many exoplanets are too close to their parent stars for even this powerful telescope to distinguish them. But we can use the trick of watching as the planet passes in front of (transits) its star. During transit, the planet blocks a small fraction of the starlight, and an even tinier fraction of the starlight is filtered through the outer layers of the planet’s atmosphere.
Gases within the atmosphere absorb some of the light – leaving fingerprints on the starlight in the form of a reduction in brightness at certain colors, or wavelengths. JWST is particularly suited to exoplanet atmosphere studies because it is an infrared telescope. Most of the gases that are in an atmosphere – such as water vapor and carbon dioxide – absorb infrared rather than visible light.
One of four separate measurements. Each bump corresponds to a different absorbing gas in the atmosphere.
NASA, ESA, CSA, Joseph Olmsted (STScI)
I am part of an international team of exoplanet scientists that has been using JWST to study a roughly Jupiter-sized planet called WASP-39b. Unlike Jupiter, however, this world takes only a few days to orbit its star, so it is being cooked – reaching temperatures exceeding 827°C. This gives us the perfect opportunity to explore how a planetary atmosphere behaves in extreme temperature conditions.
We used JWST to recover the most complete spectrum yet of this fascinating planet. In fact, our work represents the first chemical inventory of the planet’s atmosphere.
We already knew that most of this large planet’s atmosphere had to be a mixture of hydrogen and helium – the lightest and most abundant gases in the universe. And the Hubble telescope has previously detected water vapor, sodium and potassium there.
Now, we’ve been able to confirm our detection and produce a measurement of the amount of water vapor. The data also suggests there are other gases including carbon dioxide, carbon monoxide, and unexpectedly, sulphur dioxide.
Having measurements of how much of each of these gases is present in the atmosphere means we can estimate the relative amounts of the elements that make up the gases – hydrogen, oxygen, carbon and sulphur. Planets are formed in a disc of dust and gas around a young star, and we expect different amounts of these elements to be available to a baby planet at different distances from the star.
WASP-39b appears to have a relatively low amount of carbon relative to oxygen, indicating it probably formed at a greater distance from the star where it could have easily absorbed water ice from the disc (boosting its oxygen), compared with its current very close orbit. If this planet has migrated, it could help us develop our theories about planet formation, and would support the idea that the giant planets in our Solar System also did a fair bit of moving and shaking early on.
A sulfurous key
The amount of sulphur we detected relative to oxygen is quite high for WASP-39b. We’d expect sulphur in a young planetary system to be more concentrated in bits of rock and rubble than as an atmospheric gas. So this indicates that WASP-39b might have undergone an unusual amount of collisions with sulphur-containing chunks of rock. Some of that sulphur would be released as gas.
In a planet’s atmosphere, different chemicals react with each other at different rates depending on how hot it is. Usually, these settle into an equilibrium state, with the total amounts of each gas remaining stable as the reactions balance each other. We managed to predict what gases we would see in WASP-39b’s atmosphere for a range of starting points. But none of them came up with sulphur dioxide, instead expecting any sulphur to be locked up in a different gas, hydrogen sulphide.
Photochemistry on WASP-39b. NASA/JPL-Caltech/Robert Hurt; Center for Astrophysics-Harvard & Smithsonian/Melissa Weiss
The missing piece of the chemical jigsaw puzzle was a process called photochemistry. This is when the rates of certain chemical reactions are driven by energy from photons – packets of light – coming from the star, rather than by the temperature of the atmosphere. Because WASP-39b is so hot, and reactions generally speed up at higher temperatures, we didn’t expect photochemistry to be quite as important as it has turned out to be.
The data suggests that water vapour in the atmosphere is split apart by light into oxygen and hydrogen. These products would then react with the gas hydrogen sulphide, eventually stripping away the hydrogen and replacing it with oxygen to form sulphur dioxide.
What’s next for JWST?
Photochemistry is even more important on cooler planets that may be habitable – the ozone layer on our own planet is formed via a photochemical process. JWST will be observing the rocky worlds in the Trappist-1 system during its first year of operation. Some of these measurements have already been made – and all of these planets have temperatures more similar to Earth’s.
Some may even have the right temperature to have liquid water on the surface, and potentially life. Having a good understanding of how photochemistry influences atmospheric composition is going to be critical for interpreting the Webb telescope observations of the Trappist-1 system. This is especially important since an apparent chemical imbalance in an atmosphere might hint at the presence of life, so we need to be aware of other possible explanations for this.
The WASP-39b chemical inventory has shown us just how powerful a tool JWST is. We’re at the start of a very exciting era in exoplanet science, so stay tuned.
Russian shelling of the southern Ukrainian city of Kherson killed 15 civilians Friday, officials said, as engineers across the country sought to restore heat, water and power to major cities.
Throughout the country, Russian air strikes in recent weeks have brought Ukraine's energy infrastructure to its knees as winter approaches and temperatures near freezing, spurring fears of a health crisis and a further exodus.
Ukrainian President Volodymyr Zelensky said more than six million households in the country were still affected by power cuts, two days after targeted Russian strikes on Ukraine's energy infrastructure.
The country's national energy company, Ukrenergo, said late Friday that the grid was still facing a 30 percent deficit, with its technicians working "around the clock" to restore power. But it said it expected to increase coverage over the weekend, boosted by additional nuclear power.
The attack on Kherson, a key southeastern city recently recaptured by Ukrainian forces, marked the deadliest Russian bombardment in recent days.
A total of "15 residents were killed and 35 injured, including one child, as a result of enemy shelling", city official Galyna Lugova said. Several "private houses and high-rise buildings" had been damaged, she added.
"The Russian invaders opened fire on a residential area with multiple rocket launchers. A large building caught fire," said Yarovslav Yanushovich, head of the Kherson military administration.
Earlier Friday, the region's governor said patients in the city hospital and others from a psychiatric unit had been evacuated because of "constant Russian shelling".
The Kherson city council said it was offering to evacuate civilians to other regions.
The attacks on power stations and other infrastructure resources throughout Ukraine are Russia's latest attempt to force Ukrainian capitulation after Moscow's forces failed to topple the government and capture Kyiv in the war's early stages.
In the capital, where about half of residents were still without power two days after Russian strikes hammered the country's energy grid, engineers worked to restore services.
"We have to endure this winter, a winter that everyone will remember," Zelensky said on social media, as UK Foreign Secretary James Cleverly visited to announce a new aid package.
Ukrainian Prime Minister Denys Shmygal told a government meeting, "Almost all Ukraine's critical infrastructure has been reconnected."
Critical infrastructure includes water utilities, heat generation plants, hospitals and emergency services.
But Shmygal said ordinary consumers continued to face scheduled power cuts across every region of the country.
Ukraine's Western allies have denounced the Russian attacks on energy infrastructure as a "war crime". The strikes have come in the wake of a string of military setbacks for Russia on the frontlines.
Moscow insists it is targeting only military-linked infrastructure and has blamed Kyiv for the blackouts, saying Ukraine can end the suffering by agreeing to Russian demands.
Putin meets mothers
Meanwhile, for the first time since he launched the war in February, Russian President Vladimir Putin met the mothers of soldiers fighting in Ukraine, assuring those whose children had been killed that he and Russia's elite "share this pain".
"I want you to know I, personally, and the entire leadership of the country share this pain," he told them.
He said that many reports about the conflict could not be trusted, describing them as "fake news, deceit and lies".
Russia has introduced legislation that effectively bans public criticism of the war.
Kremlin critics accuse authorities of concealing the real number of dead and wounded Russian troops.
Anger and concern have built across Russia since the Kremlin announced in September that hundreds of thousands of well-trained and well-equipped conscripts would be sent to the battlefield to bolster Moscow's struggling campaign.
But chaos ensued, with widespread reports of exempted men -- including the elderly and infirm -- being dispatched to the front and conscripts dying after receiving nearly no training, forcing the Kremlin to concede "mistakes".
Putin's meeting with the soldiers' mothers is a sign the Kremlin takes the growing malaise seriously.
Visiting Kyiv on Friday, Britain's foreign minister announced new aid for Ukraine, including ambulances and support for victims of sexual violence by Russian soldiers.
"Russia is continuing to try and break Ukrainian resolve through its brutal attacks on civilians, hospitals and energy infrastructure," Cleverly said.
"Russia will fail," he said, vowing UK support "will continue for as long as it takes".
Meanwhile, the head of Russian mercenary outfit Wagner, Yevgeny Prigozhin, said Friday that a former US Marine general and several British and Finnish fighters were operating with the group in Ukraine.
"(Finns) are fighting in a British battalion (as part of Wagner PMC), which is commanded by a US citizen, a former general of the Marine Corps," Prigozhin's press service said he told Finnish newspaper Helsingin Sanomat.
© Agence France-Presse
On November 22 and 23, meteorologists forecast heavy snow for the Texas Panhandle — including, according to some projections, up to two feet in Amarillo. And some Twitter users, upon hearing the forecast, used the snowstorm to mock and ridicule Sen. Ted Cruz.
In February 2021, Texas suffered unusually cold temperatures that put considerable stress on its power grid — which wasn’t properly winterized — and led to widespread outages. Millions of Texans found themselves without heat in freezing temperatures. During the crisis, Cruz headed to Cancun, Mexico to escape the cold and was slammed as “Cancun Cruz” by critics who argued that he was abandoning Texans when they needed help the most.
Many Twitter users haven’t forgotten the “Cancun Cruz” taunts of February 2021, and the Texas Panhandle snowstorm gave them a new opportunity to make fun of the far-right GOP senator.
Cruz doesn’t live near the Texas Panhandle, which is in the far north of Texas west of Oklahoma, but rather, in South Texas hundreds of miles away. Nonetheless, Twitter users welcomed a chance to have some laughs at Cruz’s expense.
Twitter user Tammy Sahargun, @TammySahargun, posted, “Anyone know where Ted Cruz is heading?” while @SweetPea6962 asked, “@TedCruz @SenTedCruz Have you booked your flight to Mexico yet???” And @VotingTweeter wrote, “Major snow storm is going to dump on Texas. Are you packed?”
Another Twitter user wrote, “Does Texas have any contingency plans in case what happened last winter happens again? You gonna leave people to die again? In your case, Ted, off to Mexico again?"
When Cruz fled to Mexico during the February 2021, he insisted that he came right back to Texas in response to reports on the disaster. Cruz’s critics, however, maintained that he only came back in response to the bad publicity he was receiving, not in response to the crisis itself.