Author Topic: Faking the moon landings  (Read 33147 times)

Offline MBDK

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Re: Faking the moon landings
« Reply #540 on: August 21, 2019, 12:50:25 AM »
It's just that I also wish we'd, you know, have enough low-cost treatment options so that I could be in therapy for my chronic mental health condition.
Understood, and wish you the best.
"Laugh-a while you can, monkey-boy." - Lord John Whorfin

Offline ka9q

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Re: Faking the moon landings
« Reply #541 on: August 24, 2019, 02:35:18 AM »
Despite being a mad-keen astronomy enthusiast for years, I did not know that Kitt Peak had radio telescopes. I wouldn't have even considered the possibility.
A friend (now retired) ran NASA's VLBI program for many years, and he once (late 1980s?) arranged a tour of Kitt Peak for us when we were having a conference in Tucson. Living in NJ at the time, I always looked forward to visiting Tucson in February. But being an east coaster I kinda forgot about the effect of altitude. When we left Tucson, it was raining. When we reached the site it was snowing -- heavily -- and I'd forgotten to bring a sufficiently heavy coat. Site utility power was off but it was running on propane, which was apparently a routine occurrence. We clambered around the dishes, looking at the feed rooms with their low noise amplifiers and helium refrigerators going "klump klump", occasionally clearing out so the operator could dump the accumulated snow in the dish without dumping us out too.

The "screen room" was where most of the electronics were located in the building. Because they generated radio noise, the room itself had copper mesh in the walls and door to keep that noise from escaping and getting into the antennas. I saw my first hydrogen maser there. It was a rather unassuming small rack of equipment with some lights flashing at what I presumed was exactly 1 Hz.

At that time, each location recorded data on high speed digital tape and shipped them all to a central correlator at Socorro NM, where the radio images were actually processed. Later those became shipments of pallets of hard drives, and I understand that finally they have fiber lines over which they can send data in real time.

This being before GPS, one of the main uses of the VLBI network at that time was, surprisingly enough, measuring the movement of the earth's tectonic plates. (My friend's group at NASA was called "Crustal Dynamics".) They'd all observe some distant, strong radio source in a known celestial location and compute the exact straight-line "baseline" distance (to millimeter accuracy) between the phase centers of each pair of antennas. The first map I ever saw of the annual movements of the plates in the state of California was produced by this network. I think they still determine the precise rotational position of the earth and the locations of the earth's rotational poles (they wander by a few tens of meters, IIRC).
« Last Edit: August 24, 2019, 02:38:42 AM by ka9q »

Offline bknight

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Re: Faking the moon landings
« Reply #542 on: August 24, 2019, 11:46:33 AM »
Is this VLBI(I had to look that one up) capable of predicting earthquakes by studying the past movement of the Earth prior to earthquakes?
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline ka9q

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Re: Faking the moon landings
« Reply #543 on: August 26, 2019, 05:12:51 AM »
No one (and nothing) can, as yet, predict earthquakes. VLBI, like GPS, can only measure the relative motions of the observing stations on the ground as they move with the crustal plates.

VLBI can in addition measure the precise orientation of the earth's rotational poles relative to the stars and its precise rotational position and angular velocity. Because the earth's rotational angular momentum is known (constant except for what it's slowly losing via tides) this can tell you interesting things about how mass moves within, on and near the earth (e.g., the ocean and atmosphere). I think it has even been able to detect sudden changes after major earthquakes. But it still can't predict them.
 
« Last Edit: August 26, 2019, 05:14:33 AM by ka9q »

Offline bknight

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Re: Faking the moon landings
« Reply #544 on: August 26, 2019, 02:15:25 PM »
I agree that earthquake prediction at the present is not predictable. I guess what I was thinking was measure and study movements prior to an earthquake, this would happen after the earthquake then develop a dB of movements that then would be used to predict future ones.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline ka9q

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Re: Faking the moon landings
« Reply #545 on: August 27, 2019, 09:48:09 AM »
I'm sure it's not for a lack of trying that this hasn't been done.

The problem is that while earthquakes are statistically predictable in the long term (there will be more earthquakes along the Pacific/North American plate boundary) they are very chaotic and unpredictable in the short term. Even the aftershocks after a large earthquake can only be predicted statistically, although those statistics do change in known ways.