Tuesday, 2 March 2010
Chile Earthquake causes Shift in Earths Axis
Chile and the Andes mountains, as seen from Space Shuttle Columbia during Nasa's STS-65 mission in 1994.
Chile and the Andes mountains, as seen from Space Shuttle Columbia in 1994
Richard Gross, a research scientist at Nasa's Jet Propulsion Laboratory in California, calculated how much the axis may have changed in position following the the disaster.
More than 700 people died and two million are estimated to have been affected by the 8.8-magnitude tremor and subsequent tsunamis.
The quake, the most powerful to hit the nation in 50 years, sent shockwaves out from the epicentre 70 miles from Chile's second city, Concepcion.
Buildings and roads collapsed and 500,000 homes have been left severely damaged.
Six aid workers died when a plane carrying them to Concepcion crashed.
The team was on its way to help organise accommodation for those left homeless by the disaster.
Soldiers were sent to patrol Concepción's streets after mobs set fire to shops and started looting them, hindering attempts to rescue survivors.
A Santiago highway collapsed during the quake, scattering cars (PA)
Devastation after the Chile quake
If the planet's axis did shift by 8cm during the quake, days would have shortened by 1.26 microseconds, Mr Gross calculated.
A microsecond is one-millionth of a second.
Earth days are 24 hours long because that is the amount of time it takes the planet to make one full rotation on its axis, so shifting the axis would affect rotation.
The quake shifted the Earth's axis by even more than the 9.1-magnitude tremor off Indonesia that started the deadly tsunami in Asia in 2004, according to Mr Gross.
This was partly because the fault line responsible for the quake in Chile "dips into Earth at a slightly steeper angle than does the fault responsible for the 2004 Sumatran earthquake", he said.
The different angle made Saturday's tremor more effective at moving Earth's mass vertically and shifting the planet's axis, Mr Gross continued.
The 2004 quake in Asia, which killed hundreds of thousands of people, caused the Earth to move by around 7cm.
It chopped an estimated 6.8 microseconds off the length of a day, Nasa said.
Area 51-Fact or Fiction?
Area 51 is a military base, and a remote detachment of Edwards Air Force Base. It is located in the southern portion of Nevada in the western United States, 83 miles (133 km) north-northwest of downtown Las Vegas. Situated at its center, on the southern shore of Groom Lake, is a large secretive military airfield. The base's primary purpose is to support development and testing of experimental aircraft and weapons systems.
The base lies within the United States Air Force's vast Nevada Test and Training Range. Although the facilities at the range are managed by the 99th Air Base Wing at Nellis Air Force Base, the Groom facility appears to be run as an adjunct of the Air Force Flight Test Center (AFFTC) at Edwards Air Force Base in the Mojave Desert, around 186 miles (300 km) southwest of Groom, and as such the base is known as Air Force Flight Test Center (Detachment 3).
Though the name Area 51 is used in official CIA documentation, other names used for the facility include Dreamland, Paradise Ranch, Home Base, Watertown Strip, Groom Lake, and most recently Homey Airport. The area is part of the Nellis Military Operations Area, and the restricted airspace around the field is referred to as (R-4808N), known by the military pilots in the area as "The Box" or "the Container".
The intense secrecy surrounding the base, the very existence of which the U.S. government barely acknowledges, has made it the frequent subject of conspiracy theories and a central component to unidentified flying object (UFO) folklore.