Waves of lava seen in largest volcanic crater on Jupiter's moon
Series of LBTO images showing Europa crossing the disk of Io. Loki Patera is the bright hot spot in the upper part of the disk. Europa appears dark because water ice on its surface absorbs incident sunlight, while the sulfur dioxide ice on Io's surface is less absorbing at this wavelength. Credit: Large Binocular Telescope Observatory
Researchers have taken advantage of a rare orbital alignment between two of Jupiter's moons, namely Io and Europa, and obtained an exceptionally detailed map of the largest lava lake on Io.
On March 8, 2015, Europa passed in front of Io, the most volcanically active body in the solar system, gradually blocking out light from the volcanic moon. Because Europa's surface is coated in water ice, it reflects very little sunlight at infrared wavelengths, allowing researchers to accurately isolate the heat emanating from volcanoes on Io's surface.
The infrared data showed that the surface temperature of Io's massive molten lake steadily increased from one end to the other, suggesting that the lava had overturned in two waves that each swept from west to east at about a kilometer, or 3,300 feet, per day.
Overturning lava is a popular explanation for the periodic brightening and dimming of the hot spot, called Loki Patera after the Norse god. The most active volcanic site on Io, Loki Patera is about 200 kilometers, or 127 miles, across. The hot region of the patera, a bowl-shaped volcanic crater, has a surface area of 21,500 square kilometers.
Astronomers first noticed Io's changing brightness in the 1970s, but only when the Voyager 1 and 2 spacecraft of the U.S. National Aeronautics and Space Administration (NASA) flew by in 1979 did it become clear that this was because of volcanic eruptions on the surface.
Despite highly detailed images from NASA's Galileo mission in the late 1990s and early 2000s, astronomers continue to debate whether the brightenings at Loki Patera, which occur every 400 to 600 days, are due to overturning lava in a massive lava lake, or periodic eruptions that spread lava flows over a large area.
"If Loki Patera is a sea of lava, it encompasses an area more than a million times that of a typical lava lake on Earth," said Katherine de Kleer, a University of California, Berkeley, graduate student and the lead author of a study published in the journal Nature. "In this scenario, portions of cool crust sink, exposing the incandescent magma underneath and causing a brightening in the infrared."
The images leading to the new findings were obtained by the twin 8.4-meter, or 27.6-foot, mirrors of the Large Binocular Telescope Observatory in the mountains of southeast Arizona, a state in the southwestern United States, linked together as an interferometer using advanced adaptive optics to remove atmospheric blurring. The facility is operated by an international consortium headquartered at the University of Arizona in Tucson.
"This is the first useful map of the entire patera," co-author Ashley Davies, of the Jet Propulsion Laboratory in Pasadena, Southern California, was quoted as saying in a UC Berkeley news release. "It shows not one but two resurfacing waves sweeping around the patera. This is much more complex than what was previously thought."
"This is a step forward in trying to understand volcanism on Io, which we have been observing for more than 15 years, and in particular the volcanic activity at Loki Patera," noted Imke de Pater, a UC Berkeley professor of astronomy.
Jaywalkers to face fine from May 30
The Metropolitan Traffic Police Division (MTPD) is to fine jaywalkers Rs 200 per person effective from May 30. Chief of the MTPD, Deputy Inspector General Mingmar Lama said the Division is also to conduct a road safety campaign to reduce the number of road fatalities in view of 40 percent of the total deaths in a year resulting from road accidents involving pedestrians.
Lady Justice statue removed from Bangladesh court complex
A statue of Lady Justice was removed from Bangladesh’s Supreme Court premises under tight security after Islamist hard-liners pressed for its removal, the sculptor said Friday. The statue of a woman holding a scale and sword in her hands was installed in December outside the court building. The woman is wrapped in a sari, a Bangladeshi revision of the usual representation, the Greek goddess Themis blindfolded and clad in a gown.
Two boys missing in Narayani River found dead
Two boys, who went missing in the Narayani River on Thursday, were found dead Friday. Ashish Shrestha, 18, of Gaindakot-1 and Bhupendra KC, 17, of Gaindakot-8 went missing on Thursday in course of swimming.
- Sole gharial in Chitwan National Park found dead
Pilgrim drowns in Gosaikunda
A pilgrim drowned in a lake in Gosaikunda Friday morning while taking a holy dip. The deceased has been identified as Rojina Karki, 40, of Naikap of Chandragiri Municipality-14, Kathmandu, police said. She arrived here along with her kin three days ago on a religious trip to observe the Ganga Dasahara Festival kicked off from today.
Oops! Deuba does it again
Deuba and Dahal have made a mockery of the constitutional provision of impeachment as a weapon of last resort with its preemptive registration as a tactical move to stop CJ Karki from delivering justice. This will set a bad precedent and there will be more such tactical use of impeachment in the future considering how justices at the SC are being appointed in political quotas in recent times.
Challenges for reconstruction
One of the major challenges faced in the reconstruction process of Nepal is the absence of elected local government. Lack of government in local level was reflected in the major pre-disaster and post-disaster events, where it took months to reach the affected region and still no widely-accepted data is available. In the absence of an elected local government, top-down approach of governance has its own accountability deficit.
Apil KC/Keshab Sharma
Jhamsikhel as I knew
Hari-ko-pasal, right at the said junction used to be the place to buy any household item ranging from food grains and other household items. There was nothing that he did not have. Most often he loved keeping his customers waiting, more so if they were younger. He kept his client engaged with jokes and tole gossip.
Empowering local bodies
It is common to rent a room or two based on nothing more than a verbal contract. There are two types of owners. There are many who rent legal properties informally and those who rent out illegally built ones. The rental space demand is so much that owners openly flout bylaws by building more number of floors than approved. It is difficult, as it is, to bring both type of owners within the system.
Traffic Police in Kathmandu
As busy and hassling as the traffic system in Kathmandu is, the Traffic Police here have to handle an equally strenuous job. Over 1,400 traffic officers in and around the Kathmandu Valley battle against the pestering traffic and air pollution each day.
Menstrual taboo outdated
I have seen my sisters and friends isolated and treated in discriminatory manner during their first menstruation cycle. They were not allowed to look at the sun, to touch water source, flower, fruits, any male family member, nor even hear their voice. The activist may claim the situation has changed and I do agree but still during every month my loved ones turns into untouchables beings.