The Land :: www.TheLandOnline.com

Nuts & Bolts

July 17, 2013

Stutters in Earth's spin changed length of days slightly

Three times in the past decade, the Earth's spin has missed a beat as seemingly random blips cause days to temporarily stretch and shrink. They have emerged from the clearest-ever view of how long a day is.

Earth's rotations fluctuate as the oceans and the atmosphere push and tug on the spinning planet. But these small daily variations hide longer-term patterns.

Richard Holme of the University of Liverpool looked at 50 years of GPS and astronomical data to see how day length varied during that time. His analysis highlighted a well-known cycle of slow changes at the Earth's core, which lengthen days by a few milliseconds over roughly a decade, then shorten them again.

There's also a 5.9-year cycle, due to persistent friction between the Earth's fluid outer core and its surrounding mantle, a wobble that changes day length by fractions of milliseconds a year.

When Holme stripped away both of these regular cycles, though, sudden unexpected jumps in day length emerged from his calculations. Three times in recent years - in 2003, 2004 and 2007 - our planet's spin has stuttered. The jumps interrupted the longer-term changes by a fraction of a millisecond, and they lasted several months before going back to normal.

Satellite readings of the planet's magnetic field over the past 20 years show that the field also undergoes sudden jerks, and Holme found that they coincide with the jumps in the Earth's spin. He says the sudden changes probably occur when a patch of molten outer core temporarily sticks to the mantle, causing a steep change in angular velocity.



 

1
Text Only
Nuts & Bolts
  • Hospitals let patients schedule ER visits

    Three times within a week, 34-year-old Michael Granillo went to the emergency room at Northridge Hospital Medical Center in Los Angeles because of intense back pain. Each time, Granillo, who didn't have insurance, stayed for less than an hour before leaving without being seen by a doctor.

    July 24, 2014

  • Almost half of America's obese youth don't know they're obese

    The good news is that after decades of furious growth, obesity rates finally seem to be leveling off in the U.S.. The bad news is that America's youth still appear to be dangerously unaware of the problem.

    July 24, 2014

  • An oncologist uses scorpion venom to locate cancer cells

    Olson, a pediatric oncologist and research scientist in Seattle, has developed a compound he calls Tumor Paint. When injected into a cancer patient, it seems to light up all the malignant cells so surgeons can easily locate and excise them.

    July 24, 2014

  • 130408_NT_BEA_good kids We're raising a generation of timid kids

    A week ago, a woman was charged with leaving her child in the car while she went into a store. Her 11-year-old child. This week, a woman was arrested for allowing her 9-year-old daughter to go to the park alone. Which raises just one question: America, what the heck is wrong with you?

    July 18, 2014 1 Photo

  • Your chocolate addiction is only going to get more expensive

    For nearly two years, cocoa prices have been on the rise. Finally, that's affecting the price you pay for a bar of chocolate - and there's reason to believe it's only the beginning.

    July 18, 2014

  • Afghanistan vet who ran to grenade gets Medal of Honor

    A former Marine Corps corporal who was severely wounded when he risked his life to shield a squad mate from a grenade blast in Afghanistan was awarded the nation's highest military decoration Thursday.

    June 20, 2014

  • May 2014 was the hottest may in recorded history

    According to new data released this week, May 2014 is officially the warmest May in recorded history.
    Both NASA and the Japan Meteorological Agency have tentatively ranked May at the top of historical measurements, though NASA's numbers are preliminary because crucial information is still missing from China.

    June 20, 2014

  • Nelly-elephant.jpg Bet the farm: 5 'psychic' animals predict soccer victories

    Need some guidance on whom to place your bets for this year's World Cup? Since Paul the Octopus achieved a prediction success rate of 85 percent in 2010, hosts of animal oracles around the world have sought attention as soccer sages. Here's a look at a few of them.

    June 20, 2014 1 Photo

  • Is the FDA waging a war on artisanal cheese?

    Is the Food and Drug Administration waging a war on artisanal cheese?
    The answer depends on your perspective. But this much is certain: The agency's answer to New York regulators about using wooden boards to age cheese has caused an uproar in the domestic industry and raised questions about the status of imported cheeses that use the same process.

    June 12, 2014

  • Texting while driving is latest teen risk as smoking declines

    While smoking among American teens has fallen to a 22-year low, most adolescents admit to engaging in a new type of risky behavior: texting while driving.

    June 12, 2014

Featured Ads
Hyperlocal Search
Premier Guide
Find a business

Walking Fingers
Maps, Menus, Store hours, Coupons, and more...
Premier Guide
The Land's Twitter Feed