I sometimes wonder why tech people like space-related stuff so much. It is a major news indeed and a feat of science and technology, but why is space so popular? Because it's otherworldly, large-scale and kind of making you feel empowered or united? I'm probably more interested in mundane, obscure and humble stuff, so this disproportionate popularity of space-related news is always baffling to me.
Physicists Detect Gravitational Waves, Proving Einstein Right
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Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#422According to this paper ( https://dcc.ligo.org/LIGO-P150914/public ) they detected the signal first at Livingston, Louisiana and 6.9ms later in Hanford, Washington. The distance between them according to wikipedia ( https://en.wikipedia.org/wiki/LIGO ) is 3002km (Ok, the 3002 km distance is on the Earth). If the gravity wave travel at the speed of light they should detect 10ms later (300 000/3002 sec = 1/100 sec = 10…
Consider that the black holes merged about 1.3 billion years ago. If gravitational waves travelled 50% faster than the speed of light, they would've passed by earth long before our species came around, unless the effect of the collision went on for, say, a few million years after the event?
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#423Earlier quoted context omitted.
I'm sure He either said "let there be light" or "gee, that's funny...."
I'd prefer either "what does this button do?" or "shit, don't press that!".
Those are what you get when you figure out how to construct a machine that looks to the future and can hear what God says at the end of the universe.
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#424I sometimes wonder why tech people like space-related stuff so much. It is a major news indeed and a feat of science and technology, but why is space so popular? Because it's otherworldly, large-scale and kind of making you feel empowered or united? I'm probably more interested in mundane, obscure and humble stuff, so this disproportionate popularity of space-related news is always baffling to me.
In grappling with this question myself -- it's a good question -- I've concluded the interest is in understanding and predicting the behavior of a system based on a few laws.
The system is quite complex and full of exotic objects, so ordinary real world intuition is a poor guide. And the laws are couched in a mathematical language that is also foreign to our everyday world.
Yet, predictions can be made and tested. It's an intellectual puzzle like "what does this very tight loop do?", or "how does the Y combinator work?" -- but in a different arena.
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#425Does anyone else get a bit depressed when you consider how insignificant we are?
Does this discovery make us insignificant or does it increase our understanding of the universe?
It depends on how you look at it. You are taking a pessimist's view on things that the universe is so large and we are so small that we don't matter. If you take an optimists's view on things you'll discover that we do matter and learning new things increases our significance.
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#426Earlier quoted context omitted.
I'm sure I was not clear, since that was the first pass. What the experiment indicates is that the Earth varies in size. Roughly: measured distance of 10^-20 meters 4km is 10^-5 of earth circumference. delta Earth's circumference 10^-25 total distance change in earth's diameter = 10^-18 meters Given the non-intuitive nature of geology[1], I am saying that the possibility that the Earth varies that much in dimension d…
The LIGO detectors were very carefully constructed to rule out this sort of noise; they are the result of a lot of human engineering ingenuity. It turns out that before making this investment in instrumentation specifically for the purpose of detecting gravitational waves, the scientists in question also came up with the objections that you spent presumably less than fifteen minutes thinking of. They then spent time…
I'm old enough to remember Pons-Fleischmann. But not so old as to forget the more recent faster than light neutrinos social media storm. I've been thinking about the nature of scientific claims for more than twenty years. Few people are intentionally wrong: that doesn't mean astronomers as men of science didn't sware by the Ptolemaic cosmology.
To be clear, I am not denying the possibility of the earth expanding in and contracting in what passes for space time. I am skeptical of the proposition that the instruments are measuring the collisions of black holes is methodologically sound.
The careful preparation and engineering that occurred before LIGO was constructed resulted in an instrument that ran from 2002 to 2010 without detecting gravitational waves. The consequence of this $400 million experiment was not reexamining the theory, but sinking another $200 million into an instrument that created good tweetable data. That's the way careers and politics and human nature works.
There are three components to the theory. Spatial change, gravitational waves, and colliding massive bodies. The reason I am skeptical is that the scientists are inferring two of them: gravitational waves and colliding black holes from the component most likely to have other causes. If I had the mountaintop shells and the flood, god would be more plausible. If I have the shells and god, the flood is. Two outta three is my threshold for reasonable scientific inference in this case.
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#427Earlier quoted context omitted.
I read the article. I am in the habit of calling periodic changes in dimension "resonance." I consider it rather consistent with the use of "wave" in the discussion and hence a handy way of describing what the instruments measured rather than what the theory suggests as the first cause.
Resonance is quite a bad term if that's what you use it for. Resonance would require some amount of positive feedback. Vibration or oscillation would be a much better terms for simple periodic changes.
It's consistent with vibration caused by a wave which is why it seemed appropriate to me in this context...even if I think the claim of waves is an over-reach, I am not being deliberately argumentative.
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#428So what does this mean about the future, now? What new capability do we have? What is possible now that wasn't possible before?
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#429Earlier quoted context omitted.
Gravitational waves are a prediction of classical linearlized gravity - gravitational waves are to (classical) gravitons what light waves are to photons.
But we have direct experimental confirmation of light behaving light both a wave and as a particle. Do we have any such evidence to show gravity exhibiting particle like behavior?
No, but we predict it to be essentially impossible to observe a graviton.
http://arxiv.org/abs/gr-qc/0601043
Re: Physicists Detect Gravitational Waves, Proving Einstein Right
#430I sometimes wonder why tech people like space-related stuff so much. It is a major news indeed and a feat of science and technology, but why is space so popular? Because it's otherworldly, large-scale and kind of making you feel empowered or united? I'm probably more interested in mundane, obscure and humble stuff, so this disproportionate popularity of space-related news is always baffling to me.
Well, it's not just "space", is it?
We (as in, species) just observed a phenomenon that's related on a fundamental way to any form of matter, doesn't matter(no pun intended) if it is space or not.