How Chile's Earthquake Shortened Earth's Day
If you want to make sure you get enough sleep on Tuesday night, you might have to get to bed earlier. You don't have to adjust your schedule by much: about 1.26 millionths of a second ought to do it. According to a NASA scientist's computer modeling, that's how much an Earth day should have been shortened by the subterranean upheaval that triggered the Feb. 27 earthquake in Chile. Some basic physics explains why.
(See pictures of Chile's massive earthquake.)
Every point on the planet takes the same 24 hours or so to complete a single rotation around Earth's north-south axis, but some points have to move faster than others to spin the full 360° by the one-day deadline. That's because some parts of the planet are much bigger than others, at least in circumference. The Earth's equator is 24,901 miles around. The perimeter of the Arctic Circle, by contrast, is just 9,945 miles, and if you stand five feet from the North Pole, the circumference you inscribe as the Earth rotates is a scant 31.4 feet. Yet in all of those places, it still takes 24 hours to complete a single rotation. (The fact that points along the equator move faster than others is the reason NASA and the European Space Agency put their launch pads in Florida and French Guiana, respectively; fire off your rockets in the direction the Earth spins, and you get a free 1,000 miles per hour.)
(See the top 10 scientific discoveries of 2009.)
Earthquakes alter planetary speed in two ways. Shifting plates rearrange the distribution of the Earth's mass, causing it to bulge imperceptibly in spots it didn't bulge before and contract in others. That rearrangement should further shift the Earth's inclination, or figure axis (the axis around which the Earth's mass is balanced, which is slightly different from the north-south axis around which the Earth rotates) — in the case of the Chile earthquake, by about three inches. The law of conservation of angular momentum, however, requires that even under these exigent circumstances, the Earth's angular momentum stays constant, which means the planet must step on the gas (or the brake) to accommodate shifting mass. The same thing happened in 2004 with the 9.1 Sumatran earthquake that triggered the tsunami. That earthquake should have shifted the Earth's figure axis by 2.76 inches and shortened its day by 6.8 millionths of a second, according to computer models.
If the physics seems a bit arcane, consider that you probably spent much of the past two weeks seeing the angular-momentum principle in action — at least if you watched the Olympics. Earthquakes change the Earth's rotation the same way a twirling figure skater changes hers — by extending or tucking her arms in, for instance, to slow down or speed up accordingly. The only difference is that the skater does so decidedly more elegantly.
http://www.time.com/time/health/article ... 81,00.html
Urgent Help Needed to Adjust Clock on Respironics Machine
Urgent Help Needed to Adjust Clock on Respironics Machine
Can someone please post the details to adjust my machine's clock?
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Mask: Hybrid Full Face CPAP Mask with Nasal Pillows and Headgear |
Additional Comments: M Series Integrated Humidifier |
Rooster
I have a vision that we will figure out an easy way to ensure that children develop wide, deep, healthy and attractive jaws and then obstructive sleep apnea becomes an obscure bit of history.https://www.youtube.com/watch?v=0ycw4uaX ... re=related
I have a vision that we will figure out an easy way to ensure that children develop wide, deep, healthy and attractive jaws and then obstructive sleep apnea becomes an obscure bit of history.https://www.youtube.com/watch?v=0ycw4uaX ... re=related
Re: Urgent Help Needed to Adjust Clock on Respironics Machine
Sorry Rooster, my micrometers don't go down that small
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Mask: Swift™ FX Nasal Pillow CPAP Mask with Headgear |
Humidifier: S9™ Series H5i™ Heated Humidifier with Climate Control |
Additional Comments: Actually ResScan 3.10 |
In looking back I know my father had undiagnosed sleep apnea and he suffered greatly for it. I WILL NOT go through that. Using a cpap is easy compared to that.
Re: Urgent Help Needed to Adjust Clock on Respironics Machine
how many years before we get to adjust the earth clock by one leap second?
http://en.wikipedia.org/wiki/Leap_second
http://en.wikipedia.org/wiki/Leap_second
Re: Urgent Help Needed to Adjust Clock on Respironics Machine
It's difficult to do by yourself, but not impossible.
List of supplies:
1 Kanooter Valve (Rather difficult to find, been looking for years)
2 KGR 65's (Difficult to find at a decent price)
1 Ballpeen Frame Jig (This can be easily made using McDonald's straws)
1 Toyota throttle assembly (Make sure you get one that is 2004 and before, the 2005 and newer are a bit troublesome)
After you have these items the rest is quite self explanatory.
List of supplies:
1 Kanooter Valve (Rather difficult to find, been looking for years)
2 KGR 65's (Difficult to find at a decent price)
1 Ballpeen Frame Jig (This can be easily made using McDonald's straws)
1 Toyota throttle assembly (Make sure you get one that is 2004 and before, the 2005 and newer are a bit troublesome)
After you have these items the rest is quite self explanatory.
Canada...I can't say anything nice, so I won't say anything at all.
So many cats, so few recipes.
So many cats, so few recipes.
Re: Urgent Help Needed to Adjust Clock on Respironics Machine
Don't forget you will also needjules wrote:It's difficult to do by yourself, but not impossible.
List of supplies:
1 Kanooter Valve (Rather difficult to find, been looking for years)
2 KGR 65's (Difficult to find at a decent price)
1 Ballpeen Frame Jig (This can be easily made using McDonald's straws)
1 Toyota throttle assembly (Make sure you get one that is 2004 and before, the 2005 and newer are a bit troublesome)
After you have these items the rest is quite self explanatory.
1 Skyhook
for lifting everything into place