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Comment by 01100011 | Hacker News Reader

Or there's a common trigger event, like, say, a large gravitational wave or a passing cloud of weakly interacting matter(dark matter?) which triggers both increased cosmic ray emissions along with earthquakes.

Not that I believe any of this, but it seems we're just pulling stuff out of our asses so I figured I'd give it a shot.

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>gravity wave

LIGO, the gravity wave detecting interferometer, has arms 4 kilometers long. Along that distance, it can detect a change in length one ten thousandth the diameter of a proton. With an instrument that sensitive, it can just barely detect a handful of gravity waves a year, out of the thousands? that occur in the observable universe. Gravity waves are subtle things.

There are different kinds of gravitational waves, LIGO doesn't see them all.

> ground-based detectors like LIGO measure the higher frequencies, pulsar timing arrays measure the lower frequencies, and space-borne detectors like eLISA measure stuff in the middle.

Does this data correlate with weather events, earthquakes or cosmic rays?

Weather events and earthquakes - no.

Cosmic rays - Astrophysical events that generate gravitational waves can also generate electromagnetic and particle emissions. If a black hole crashes into a neutron star, all kinds of stuff is going to come out.

Also, gravitational* waves. Gravity waves are something else: https://en.wikipedia.org/wiki/Gravity_wave

I guess the question becomes if tectonic plates be more or less sensitive?

They are significantly impacted by tides for example.

One aspect of gravity waves is that other than being extremely weak, they cannot perform work. So they don't cause mechanical forces.

This is not true, and in fact there is a very famous thought experiment called the "sticky bead argument" that was pivotal in developing the consensus that gravitational waves are a real, physical effect and not just a "gauge" effect (an artifact of the coordinate system):

https://en.wikipedia.org/wiki/Sticky_bead_argument

On the other hand, I definitely agree that gravitational waves are almost certainly too weak to cause any tectonic effects.

I had heard that somewhere before, but it looks like I'm wrong

Oh really? I didn't know that. If they cannot perform work, how can we detect them?

The OP might be making a more subtle point, but my understanding is they absolutely can do work. We can measure the deceleration of binary neutron stars with a rate predicted by the emission of gravitational waves. Deceleration == work.

However, we can also measure things that don’t do work, for example, a static magnetic field does no work on a charged particle (it cannot change its kinetic energy) but look at the swirls in a cloud chamber and it’s clear as day if there’s a magnetic field there.

I'm wrong on the work thing, but I don't think we can always regard deceleration as work, since that only works for Newtonian mechanics. Under GR there is an extra term in the equation allowing for acceleration without work.

Wait, really? Why not? That's fascinating

Edit: ah, you mean for any practical purposes. Duh.

It's a tangent, but gravimeters[1] are really impressive feats of engineering.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5713048/

we should definitely just reverse the shield polarity and be done by the third act. hopefully the robot can learn a lesson about humanity before the end credits.

I’m afraid only the power of love and empathy and togetherness can resolve this climax

Discovery will probably be the only Star Trek show that I never finish watching. So far season 1 of Strange New Worlds has been pretty good. (And each season of Picard was way better than the previous.)

Same. The first season was enough for me. Never again.

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