WASHINGTON The melting of glaciers caused by the world's rising temperatures appears to be causing a slight slowing of the Earth's rotation in another illustration of the far-reaching impact of global climate change, scientists said on Friday.
The driving force behind the modest but discernible changes in the Earth's rotation measured by satellites and astronomical methods is a global sea level rise fueled by an influx of meltwater into the oceans from glaciers, the researchers said.
"Because glaciers are at high latitudes, when they melt they redistribute water from these high latitudes towards lower latitudes, and like a figure skater who moves his or her arms away from their body, this acts to slow the rotation rate of the Earth," Harvard University geophysicist Jerry Mitrovica said.
The movement of ice and meltwater is also causing a slight migration of the Earth's axis, or north pole, in a phenomenon known as "polar wander," the researchers said.
"Imagine a figure skater who doesn't stick their arms straight out but rather sticks one at one angle and the other out at another angle. The figure skater will begin to wobble back and forth. This is the same thing as polar motion," Mitrovica said.
The research looked at the changes in the planet's rotation and axis in light of the world's sea level rise in the 20th century as a result of increasing global temperatures.
The melting of the ice sheets and the rise in sea levels moved the planet's rotation axis, or north pole, at rates of less than a centimeter per year, Mitrovica said. This melting slowed the Earth's rotation and increased the duration of a day by about a thousandth of a second over the 20th century, Mitrovica said.
"These are small effects," but are another indication of the profound impact of human-induced climate change on the planet, Mitrovica said. The observed rotation slowdown does not pose a danger to the planet, he said.
If polar ice sheets melt at higher rates this century, as experts forecast them to do, the impact on Earth's rotation will grow, Mitrovica said.
The research was published in the journal Science Advances.
(Reporting by Will Dunham; Editing by Sandra Maler)
CAPE CANAVERAL, Fla. NASA missed opportunities to save millions of dollars following Orbital ATK’s failed cargo run to the International Space Station last year, the agency’s top watchdog said on Thursday.
The NASA Office of Inspector General also questioned Orbital’s plan to resume deliveries to the space station, a permanently staffed, $100 billion research laboratory that flies about 250 miles (400 km) above Earth.
Orbital is buying rides for its next two Cygnus cargo capsules from United Launch Alliance (ULA), a partnership of Lockheed Martin and Boeing. Orbital’s first mission using ULA’s Atlas rocket is slated for December, with the second to follow in early 2016.
Orbital also is outfitting its troubled Antares rocket, which exploded seconds after liftoff from Virginia on Oct. 28, 2014 with new engines. The revamped booster will then be used for two more station resupply missions in 2016, a schedule that the does not include a test flight and has limited opportunities for ground testing and certification, the Inspector General report said.
Orbital’s plan to return to flight “contains technical and operational risks and may be difficult to execute as designed and on the timetable proposed,” the report said.
Orbital declined to comment.
Auditors also pointed out that the U.S. space agency could have saved up to $84 million by taking advantage of provisions in its $1.9 billion contract with Orbital.
For example, NASA could have saved $21 million after Orbital launch delays resulted in multiple missions flying in 2014. Instead, NASA accepted concessions worth about $2 million, investigators said.
Orbital successfully flew two of its planned eight missions before the accident.
The company now plans to fulfill its contract requirements in seven flights by using the heftier Atlas and revamped Antares launchers. However, on a price-per-pound basis, as stated in the original contract, NASA is paying an extra $65 million for those missions, the report showed.
In a written response to the Inspector General, NASA said it had made use of available contract provisions in its negotiations with Orbital.
The oversight agency is conducting a similar review of NASA's relationship with privately owned SpaceX, which operates a second cargo line to the space station. SpaceX, owned and operated by technology entrepreneur Elon Musk, is recovering from a June 28 accident of its Falcon 9 rocket, which destroyed another station resupply ship.
(The story was refiled to correct the time element in the lead paragraph to "last year" instead of "two years ago")
(Reporting by Irene Klotz; Editing by Tom Brown)
WASHINGTON The Inuit, a group of people who make the Arctic their home, have benefited from a handy set of genetic adaptations that help them survive in some of Earth's harshest conditions.
Scientists on Thursday said a study of the genomes of Inuit from Greenland revealed unique genetic variants related to fat metabolism that ward off cardiovascular disease that otherwise could be caused by a diet traditionally high in fat from blubbery seals and whales.
These genetic mutations, which the researchers said arose perhaps 20,000 years ago, help lower "bad" LDL cholesterol and fasting insulin levels, limit the height of the Inuit, keep down their weight and help them adapt to a cold environment.
"Our study is perhaps the most extreme example to date of a genetic adaptation to a specific diet," said computational biology professor Rasmus Nielsen of the University of California, Berkeley and the University of Copenhagen.
"The mutations we find seem to compensate physiologically for a large intake of animal fat and are largely an adaptation to a lifestyle in which you have a high-caloric intake of fat from marine mammals, and possibly also from other mammals."
The Inuit, formerly called Eskimos, are indigenous people in Greenland and Arctic regions of Canada and Alaska.
The researchers examined genomes of 191 Inuit, 60 Europeans and 44 Han Chinese. The genetic variants found almost universally in the Inuit were much rarer in the Europeans (2 percent) and Chinese (15 percent).
The research, published in the journal Science, is the latest to illustrate human genetic adaptation to environmental conditions.
"One of the best examples is the Tibetans' adaptation to high altitude," said University of Copenhagen computational biology professor Anders Albrechtsen, referring to a study showing that many Tibetans possess a rare variant of a gene involved in carrying oxygen in the blood, helping them in high-altitude, low-oxygen conditions.
The Inuit findings may shed light on the value of diet supplementation with omega-3 fatty acids and fish oils. Nielsen noted such supplementation was originally motivated by observations that Inuit people had a high intake of fat but low cardiovascular disease incidence, so the particular form of fat they got in their diet might be healthier than other kinds.
"Our study shows that lessons from the Inuit cannot be extrapolated to other populations. The Inuit have special genetic variants that might allow them to function better on a diet rich in omega-3s than other populations," Nielsen said.
(Reporting by Will Dunham; Editing by Eric Walsh)
CAPE CANAVERAL, Fla. The first manned test flight of NASA's new deep-space Orion capsule faces a likely two-year-year delay until 2023 due to development and budget concerns, officials with the U.S. space agency said on Wednesday.
The capsule, along with its multibillion-dollar heavy lift launcher, are the most expensive parts of a long-term U.S. human space exploration initiative leading toward a crew landing on Mars in the mid-2030s.
NASA had been aiming for its first crew test flight of Orion in August 2021. But on a conference call Wednesday, NASA Associate Administrator Robert Lightfoot told reporters the agency had lost confidence in that date.
Given technical, financial and management hurdles the capsule will face during development, he said an April 2023 launch date now seemed more likely.
NASA plans to spend another $6.77 billion between October 2015 and April 2023 for two of the new Orion capsules, which are currently under development by lead contractor Lockheed Martin Corp.
The agency has already has paid $4.7 billion for Orion design and development, Lightfoot said.
He said an unmanned Orion was still scheduled for liftoff in December 2018, carried aloft by a Space Launch System (SLS) rocket that is the focus of a separate $7 billion development effort.
NASA intends to first test an Orion capsule in a lunar orbit, then use it for a mission to rendezvous with a boulder that has been robotically plucked from the surface of an asteroid and positioned into an distant orbit around the moon.
“We’re really trying to build a program,” said William Gerstenmaier, NASA associate administrator for human exploration and operations. “Ultimately, we’d like to get where we’re flying these missions about once per year.”
NASA last year announced an expected year-long schedule slip for the debut flight of the SLS rocket, previously targeted for November 2017.
So far, the agency has not provided cost estimates for any missions or production cost beyond the first test flight of Orion, the U.S. Government Accountability Office said in a report issued in July.
NASA spent about $9 billion between 2005 and 2010 on a previous human space exploration initiative called Constellation. That included $5.8 billion for an earlier version of Orion.
(Reporting by Irene Klotz; Editing by David Adams and Tom Brown)