By Leika Kihara and Kaori Kaneko TOKYO (Reuters) - A spike in coronavirus infections in Japan is driving local households to do what they have always done in times of crisis: spend less and save more, stoking fears of a deeper retail recession and grinding deflation. Fifty-year-old Hiromi Suzuki is doing just that having quit her job at a Tokyo novelty store in December after the pandemic hit sales. "I try not to spend money," she said, walking her dog in the city. "Since I don't go out much, I don't buy cosmetics or clothes any more." Suzuki's case exemplifies the trouble Japan faces as COVID...
We may have walked on the Moon and sent probes across the solar system, but we know very little about what's going on inside other planets. Now, for the first time, we have been able to view the interior of one, thanks to Nasa's Mars InSight probe. The probe, which landed in 2018, is equipped with a solar-powered lander bristling with equipment, including a seismometer (a very sensitive vibration detector).
The results, published in three studies in Science, throw up some unexpected findings about Mars's interior, including a very large core.
Though Mars has no tectonic plates, the first “marsquakes" were detected within months of the probe landing. These may result from vibrations caused by meteorites hitting the surface or from processes inside the planet.
It is difficult to detect quakes on Mars, partly because the seismometer is subject to the extremes of Martian weather, with seasonally changing windy periods obscuring the data. The signals used to probe the Martian interior all come from relatively small quakes, the best among the hundreds detected so far.
Planets grow by accumulating material (accretion) early in the life of a solar system. But their interiors are not a uniform mix of these initial ingredients – they also undergo differentiation, where some lighter minerals “float" towards the surface, while heavier components like iron sink towards the planet's centre. We expect rocky planets like Mars to have an iron-rich core, followed by a silicate layer called the mantle and an outermost skin known as the crust. Until now, how much of Mars each of these layers occupied was unknown.
It's impossible to get a sample of Mars's core. Instead, to estimate its size, we used seismic waves (created by marsquakes). On Earth, the core's radius was first estimated by finding its “shadow" – an area where the core disrupts the arrival of seismic waves from distant earthquakes. Our study had to rely on a particular kind of slow, sideways-travelling waves called S-waves which have been reflected back to the surface by the interface between the core and the mantle.
Careful seismic processing by seismologists from around the world revealed signals from six marsquakes relatively close to the probe. Combined with information from mineral physics and from seismic waves travelling through the mantle, we were able to estimate the size and density of the Martian core. This suggests that the radius is a whopping 1,830km (give or take 40km) – just over half of the planet's radius, which is bigger than we thought.
Shear waves travel from a marsquake and reflect off the iron-nickel core. (Chris Bickel/Science)
The larger than expected core requires that a relatively large proportion of lighter elements must be mixing with its iron. From our work, we now know that the Martian core should contain a high fraction of sulphur and other light elements. Experiments show that liquid iron compounds containing this much sulphur are unlikely to solidify at the pressures and temperatures we expect at the centre of Mars, so it is unlikely that it has an inner solid core as Earth does. This may help us understand why there is no planet-wide magnetic field on Mars today, unlike on Earth.
Layers and layers
A planet's crust comprises a tiny fraction of its mass. But the Martian crust's chemical and thermal interactions with the atmosphere, and with any water or ice present, helps set the conditions that determine whether life can exist there.
In the second new study, another team investigated seismic waves which converted from P-waves, which are rapid, compressional waves, to S-waves (or vice versa) when they encountered different rocky material, and an assessment of background vibrations and gravity, to probe the Martian crust. This suggested the possible average Martian crust thickness is between 24km to 72km. This means we can rule out earlier estimates of up to about 100km.
From over 100 years of seismology on Earth, we know that beneath the thin crust lies the mantle, but the mantle itself is not uniform all the way to the core. The upper mantle and the crust, collectively known as the lithosphere, are rigid, while the lower mantle is a solid that can flow. On Earth, it is the lithospheric plates that move as part of plate tectonics, but on Mars, it is unclear what role the lithosphere plays.
To sample different depths of the mantle we can use both direct and reflected seismic waves. Direct P- or S-waves dive deep into the mantle and then return to the surface. The depth they travel down to depends on the structure of the planet and the distance from the quake to the seismometer. Reflected waves return to the surface and then dive again two or three times. A third study identified eight low-frequency marsquakes that produced both direct and reflected waves, and used these to create and test different models of the Martian crust and mantle.
By comparing the data and the models, they found that Mars's lithosphere is between 400km and 600km thick. This is considerably thicker than any rigid layer seen in the Earth and implies that the Martian crust has a higher concentration of radioactive heat-producing elements than previously thought.
We now know more about the ingredients that went into building Mars, and that it has a very thick lithosphere, allowing our smaller sister planet to retain its internal heat. Though future astronauts won't have to worry about the small marsquakes we used to probe the red planet, the lack of a magnetic field generated by the sulphur-rich core will mean they and their equipment will need to be more careful of the harsh solar wind.
Our new understanding of the Martian interior is part of a new era of planetary seismology, more than fifty years since the Apollo missions landed seismometers on the Moon. New seismometers will be deployed to the Moon as part of the Artemis mission, while the Dragonfly mission will place a seismometer on Saturn's moon Titan in the mid-2030s. These experiments will help us understand more about how planets form and evolve – seeing deep into Mars is just one piece of a solar-system sized puzzle.
Trump ally Thomas Barrack reaches deal with prosecutors to free him from jail before corruption trial
Billionaire Trump ally Thomas Barrack has reached a deal with prosecutors that will free him from jail pending trial, CNN's Paula Reid reports.
Barrack was arrested on a seven-count indictment that included illegal lobbying for the United Arab Emirates, obstruction of justice, and lying to the FBI.
Barrack was chairman of Trump's inaugural committee, which has also faced allegations of misconduct. Both Ivanka Trump and Donald Trump, Jr. have faced allegations of lying during investigations into the committee.
The judge overseeing the case approved the release of Barrack on a $250 million bond. "The order requires the release bond — which is among the highest ever set in the world — to be secured by $5 million cash," CNBC reported. "It also includes restrictions on Barrack, who will be fitted with an electronic bracelet, GPS monitoring, in addition to being subject to a curfew and to the surrender of his passport."
Because Barrack is a billionaire, prosecutors had worried he might be a flight risk.
Matthew Grimes and Rashid Sultan Rashid Al Malik Alshahhi were also charged in the case.
For the first time, federal prosecutors have spelled out in court documents why they believe there simply is no legitimate legal comparison between Capitol insurrectionists and racial-justice protesters who took to the streets in the wake of George Floyd's murder last year.
The New York Times reported Friday that Jan. 6 rioter Garret Miller of Dallas — who once threatened to assassinate Alexandria Ocasio-Cortez — has raised a "selective prosecution defense," arguing that he's being treated worse than George Floyd protesters based on his political beliefs. The essence of Miller's argument has become a staple among right-wing media pundits and Republican politicians in recent months, cited by the likes of Ohio Rep. Jim Jordan in opposition to congressional investigations of the Capitol insurrection.
In a brief responding to Miller's argument, federal prosecutors noted that while some racial-justice protesters outside Portland's federal courthouse last year committed "serious offenses," Miller was involved in "a singular and chilling event in U.S. history" that threatened both the safety of the Capitol and "democracy itself."
"Mr. Miller, prosecutors noted, was 'part of a mob' that 'breached the Capitol building, and assaulted law enforcement with the goal of impeding congressional certification of the 2020 presidential election,'" the Times reported. "The defendants in Portland, they pointed out, never actually broke into the courthouse and never disrupted a proceeding before Congress."
In addition, prosecutors say they have stronger, more damning evidence against Miller, including his social media posts from before the insurrection about "civil war" and taking firearms to Washington, as well as surveillance video that shows him in "a fighting stance" confronting Capitol police officers. In addition to Ocasio-Cortez, Miller later took to Twitter to threaten the police officer who killed insurrectionist Ashli Babbitt, writing, "He will swing."
"Stripped to its core, Miller relies on rank conjecture in suggesting that political favoritism has guided the government's charging and plea decisions," prosecutors wrote.
A federal judge will ultimately decide the merits of Miller's argument, but the Times notes that selective prosecution defenses are rarely successful.
Don't Sit on the Sidelines of History. Join Raw Story Investigates and Go Ad-Free. Support Honest Journalism.
$95 / year — Just $7.91/month
I want to Support More
$14.99 per month