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[Steven Novella]

Special Guest: James Randi
News Items: Chile Earthquake, Darwinius Revisited, Raining Fish, Acupuncture for Depression, Haunted Hotels
Who's That Noisy
Your Questions and E-mails: Contrarion vs Skeptic, Personality Tests
Science or Fiction

[Chew]

WTN starts at 45 min.

[Trinoc]

OK, who was it who got elephant but was pipped by an email?

Oh no, another animal noise this week ... I'm hopeless at animal noises.

[seaotter]

in.

[seaotter]

WTN : Killer Whale

[gone]

The angular momentum change is related to the moment of inertia, which is related to surface area and not mass.

[Trinoc]

Is Randi becoming a geology denier now? (Only kidding!)

I don't think there needs to be a net movement of mass vertically up or down towards the Earth's centre. At any latitude other than the equator, a sideways movement of a plate north or south (like a lot or earthquakes) would cause a net movement of matter nearer to or further away from the axis, causing the length of the day to change. Also, because this happens asymmetrically on only one side (Chile, in this case) it will redistribute the moment of inertia of the planet and shift the axis a bit.

I don't agree that we can't measure these changes. GPS relies on time measurements much more accurate than a microsecond, and by averaging several GPS readings you can locate a point on the ground to within a few millimetres. In fact, seismologists make measurements like this all the time in earthquake-prone areas to see whether the ground movement is speeding up or stalling.

(Recent BBC podcast about this here)

I wonder whether GPS will now be recalibrated to take account of the new axis, or will we all have to accept that our latitude and longitude has just moved by 8cm?

[Chew]

I wonder whether GPS will now be recalibrated to take account of the new axis, or will we all have to accept that our latitude and longitude has just moved by 8cm?

The axis migrates constantly because of nutation. 8 cm is tiny compared to Earth's nutation.

[seaotter]

http://sguforums.com/index.php/topic,26495.msg657930.html#msg657930

Maybe the fish flew?

[Chew]

http://sguforums.com/index.php/topic,26495.msg657930.html#msg657930

Maybe the fish flew?

They were reported as being Perch, not "perching".

[Trinoc]

I wonder whether GPS will now be recalibrated to take account of the new axis, or will we all have to accept that our latitude and longitude has just moved by 8cm?

The axis migrates constantly because of nutation. 8 cm is tiny compared to Earth's nutation.

Then surely that is already allowed for by GPS, otherwise our readings would be way off (it's over 500 metres for a nutation of 17 seconds of arc, according to the Wiki entry). The new 8cm is in addition to this.

If GPS is constantly recalibrated relative to stations on the ground (rather than, say, stars) then this would automatically correct for something like a tilt of the axis that affects us all. There would still be a problem with ground stations on opposite sides of the fault, which move relative to each other all the time as plates move.

[Trinoc]

In my experience almost all hotels are haunted. If I try to get to sleep early in a hotel I'm always woken up by a sound like a herd of elephants tramping past my door just after the bar closes. Shortly after that, all of the televisions in the adjacent rooms inexplicably switch themselves on at full volume. Then in the morning there is violent banging and creaking from all around from about 6AM, exactly as if plumbing pipes were suddenly filling up with hot water. I don't know how anyone can sleep in a hotel with all of these paranormal things going on.

[seaotter]

[werecow]

I wonder whether GPS will now be recalibrated to take account of the new axis, or will we all have to accept that our latitude and longitude has just moved by 8cm?

The axis migrates constantly because of nutation. 8 cm is tiny compared to Earth's nutation.

Huh, interesting, I hadn't even heard of that. Chew, do you know if this is thought to have any perceptible impact on multidecadal oscillations in climate or weather patterns, or is the effect too small for that?

[janusroad]

i would love to hear an episode with mother Novella on to moderate Steve

Jay: Mom Steve's telling me what to do again
Steve: Nah Ah
Mom: Steve, it's just a game, let your brother thinks he's right. And stop being so contrarian.