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Satellite imagery shows Antarctic ice shelf crumbling faster than thought

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(Last Updated On: August 11, 2022)

Antarctica’s coastal glaciers are shedding icebergs more rapidly than nature can replenish the crumbling ice, doubling previous estimates of losses from the world’s largest ice sheet over the past 25 years, a satellite analysis showed on Wednesday.

The first-of-its-kind study, led by researchers at NASA’s Jet Propulsion Laboratory (JPL) near Los Angeles and published in the journal Nature, raises new concern about how fast climate change is weakening Antarctica’s floating ice shelves and accelerating the rise of global sea levels, Reuters reported.

The study’s key finding was that the net loss of Antarctic ice from coastal glacier chunks “calving” off into the ocean is nearly as great as the net amount of ice that scientists already knew was being lost due to thinning caused by the melting of ice shelves from below by warming seas.

Taken together, thinning and calving have reduced the mass of Antarctica’s ice shelves by 12 trillion tons since 1997, double the previous estimate, the analysis concluded.

The net loss of the continent’s ice sheet from calving alone in the past quarter-century spans nearly 37,000 sq km, an area almost the size of Switzerland, according to JPL scientist Chad Greene, the study’s lead author.

“Antarctica is crumbling at its edges,” Greene said in a NASA announcement of the findings. “And when ice shelves dwindle and weaken, the continent’s massive glaciers tend to speed up and increase the rate of global sea level rise.”

The consequences could be enormous. Antarctica holds 88% of the sea level potential of all the world’s ice, he said.

Ice shelves, permanent floating sheets of frozen freshwater attached to land, take thousands of years to form and act like buttresses holding back glaciers that would otherwise easily slide off into the ocean, causing seas to rise.

When ice shelves are stable, the long-term natural cycle of calving and re-growth keeps their size fairly constant.

In recent decades, though, warming oceans have weakened the shelves from underneath, a phenomenon previously documented by satellite altimeters measuring the changing height of the ice and showing losses averaging 149 million tons a year from 2002 to 2020, according to NASA.

The losses measured from calving outpaced natural ice shelf replenishment so greatly that researchers found it unlikely Antarctica can return to pre-2000 glacier levels by the end of this century.

The accelerated glacial calving, like ice thinning, was most pronounced in West Antarctica, an area hit harder by warming ocean currents. But even in East Antarctica, a region whose ice shelves were long considered less vulnerable, “we’re seeing more losses than gains,” Greene said.

One East Antarctic calving event that took the world by surprise was the collapse and disintegration of the massive Conger-Glenzer ice shelf in March, possibly a sign of greater weakening to come, Greene said.

Science & Technology

NASA delays moon rocket launch due to potential hurricane

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(Last Updated On: September 25, 2022)

NASA is skipping next week’s launch attempt of its new moon rocket Artemis 1 because of a tropical storm that’s expected to become a major hurricane.

It’s the third delay in the past month for the lunar-orbiting test flight featuring mannequins but no astronauts, a follow-up to NASA’s Apollo moon-landing program of a half-century ago. Hydrogen fuel leaks and other technical issues caused the previous scrubs, AP reported.

Currently churning in the Caribbean, Tropical Storm Ian is expected to become a hurricane by Monday and slam into Florida’s Gulf coast by Thursday. The entire state, however, is in the cone showing the probable path of the storm’s center — including NASA’s Kennedy Space Center.

Given the forecast uncertainties, NASA decided Saturday to forgo Tuesday’s planned launch attempt and instead prepare the 98-meter rocket for a possible return to its hangar.

Managers will decide Sunday whether to haul it off the launch pad.

If the rocket remains at the pad, NASA could try for an October 2 launch attempt, the last opportunity before a two-week blackout period. But a rollback late Sunday or early Monday likely would mean a lengthy delay for the test flight, possibly pushing it into November.

The Space Launch System rocket is the most powerful ever built by NASA. Assuming its first test flight goes well, astronauts would climb aboard for the next mission in 2024, leading to a two-person moon landing in 2025.

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NASA’s DART mission to collide with an asteroid

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(Last Updated On: September 24, 2022)

A NASA spacecraft will deliberately slam into an asteroid called Dimorphos in the early hours of Tuesday morning to see if this kind of kinetic impact can help deflect an asteroid posing a threat to Earth.

The Double Asteroid Redirection Test mission, or DART, spacecraft is about the size of a school bus, CNN reported.

It has been traveling to reach its asteroid target since launching in November 2021 and will arrive at the asteroid system at 03:44 Tuesday Kabul time.

“We are moving an asteroid,” said Tom Statler, NASA program scientist for the DART mission. “We are changing the motion of a natural celestial body in space. Humanity has never done that before.”

The spacecraft is heading for a double-asteroid system, where a tiny “moon” asteroid, named Dimorphos, orbits a larger asteroid, Didymos.

Didymos. which means “twin” in Greek, is roughly 780 meters in diameter. Dimorphos measures 160 meters across, and its name means “two forms.”

At the time of impact, Didymos and Dimorphos will be relatively close to Earth — within 11 million kilometers, CNN reported.

The spacecraft is about 100 times smaller than Dimorphos, so it won’t obliterate the asteroid. Instead, DART will try to change the asteroid’s speed and path in space.

A briefcase-size satellite from the Italian Space Agency is traveling behind DART to record what happens from a safe perspective.

Three minutes after impact, the satellite, LICIACube, will fly past Dimorphos to capture images and video of the impact plume and maybe even spy on the impact crater.

The images and video, while not immediately available, will be streamed back to Earth in the days and weeks following the collision.

The James Webb Space Telescope, the Hubble Space Telescope and NASA’s Lucy mission will observe the impact.

No asteroids are currently on a direct impact course with Earth, but more than 27,000 near-Earth asteroids exist in all shapes and sizes.

The valuable data collected by DART will contribute to planetary defense strategies, especially the understanding of what kind of force can shift the orbit of a near-Earth asteroid that could collide with our planet.

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Saudi Arabia plans to send female astronaut to space in 2023

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(Last Updated On: September 23, 2022)

Saudi Arabia said Thursday it will launch a training program with the goal of sending its own astronauts, including a woman, into space next year.

The kingdom is actively promoting science and technology as part of its wide-ranging Vision 2030 plan to overhaul its economy and reduce its dependency on oil.

The plan, championed by Saudi Arabia’s powerful Crown Prince Mohammed bin Salman, also calls for greater integration of women into the workforce of the conservative Muslim country. Saudi Arabia lifted a long-standing ban on women driving in 2018, AP reported. 

“The Saudi Astronaut Program, which is an integral part of the Kingdom’s ambitious Vision 2030, will send Saudi astronauts into space to help better serve humanity,” the Saudi Space Commission said in a statement.

“One of the astronauts will be a Saudi woman, whose mission to space will represent a historical first for the Kingdom.”

The first Arab or Muslim to travel to space was Saudi Arabia’s Prince Sultan bin Salman, a half-brother of the crown prince and an air force pilot who was part of the seven-member crew of NASA’s Discovery mission in 1985. He later served as head of the Saudi Space Commission from 2018 until last year, when he was appointed an adviser to King Salman.

The neighboring United Arab Emirates has the Arab world’s leading space program, having launched a probe into Mars’ orbit in February 2021. The UAE plans to launch its first lunar rover in November. If the moon mission succeeds, the UAE and Japan, which is providing the lander, would join the ranks of only the U.S., Russia and China as nations that have put a spacecraft on the lunar surface.

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