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Space and Astronomy Thread |
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#3051 |
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Quote:
Sorry, the Daily Mail says otherwise - http://www.dailymail.co.uk/sciencete...s-nothing.html
(Article & comments are hilarious)
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#3052 |
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I wonder what this monumental discovery will do for the search for the Theory of Everything? Gravitational waves clearly aren't acting like quantum physics would predict - their existence surely suggests a smooth, continuous spacetime? Unless LIGO will carry out experiments to test any possible granularity to spacetime the signals might betray. I seem to recall an experiment a while back to test spacetime granularity failing to find any though.
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#3053 |
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Join Date: Dec 2004
Posts: 21,645
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Quote:
Gravitational waves clearly aren't acting like quantum physics would predict - their existence surely suggests a smooth, continuous spacetime?
But that still leaves us with the problem of reconciling GR (essentially a classical theory) with quantum mechanics. If the quantum gravity theorists predicted something different, then they need to rethink their theories. But I'm not sure that any of them did predict anything different! |
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#3054 |
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Join Date: Mar 2003
Location: East London
Posts: 25,846
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Quote:
Do gravitational waves cause cancer?
![]() (the constellation) |
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#3055 |
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Join Date: Mar 2013
Posts: 3,063
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Has the Pope commented yet?
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#3056 |
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Join Date: Feb 2014
Location: The Sixth Circle of Hell
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A brief change of subject.
An excellent in depth article about the JWST from Scientific American. ![]() http://www.scientificamerican.com/ar...e-takes-shape/ |
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#3057 |
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Join Date: Mar 2014
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Quote:
A brief change of subject.
An excellent in depth article about the JWST from Scientific American. ![]() http://www.scientificamerican.com/ar...e-takes-shape/ " In some cases, Webb’s builders had to develop new technology just to confirm other new technologies worked, like the cold-resistant optical systems for monitoring mirrors inside cryogenic tanks, or the laser metrology platforms that measure and guide the precise sculpting of mirror surfaces during polishing." The amount of research and new inventions that happens during these endeavors is what helps push modern society forward. |
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#3058 |
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Join Date: Oct 2011
Location: The Nth East
Posts: 21,590
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RIP Philae
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#3059 |
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Join Date: Feb 2014
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Quote:
That was a good read. When people ask why we waste money on space, this from the article is a great reason to throw back at them.
" In some cases, Webb’s builders had to develop new technology just to confirm other new technologies worked, like the cold-resistant optical systems for monitoring mirrors inside cryogenic tanks, or the laser metrology platforms that measure and guide the precise sculpting of mirror surfaces during polishing." The amount of research and new inventions that happens during these endeavors is what helps push modern society forward. Also the concept of scientific progress and the true value of knowledge for knowledge's sake seems totally beyond them. But it is priceless. ![]() More on the discovery of gravitational waves. http://phys.org/news/2016-02-black-h...itational.html http://www.livescience.com/53697-gra...reactions.html https://www.youtube.com/watch?v=0uzicC9qujg
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#3060 |
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Join Date: Nov 2008
Location: London
Posts: 4,020
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Quote:
Sorry, the Daily Mail says otherwise - http://www.dailymail.co.uk/sciencete...s-nothing.html
(Article & comments are hilarious) |
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#3061 |
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Join Date: Mar 2013
Posts: 3,063
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Quote:
That was a good read. When people ask why we waste money on space, this from the article is a great reason to throw back at them.
" In some cases, Webb’s builders had to develop new technology just to confirm other new technologies worked, like the cold-resistant optical systems for monitoring mirrors inside cryogenic tanks, or the laser metrology platforms that measure and guide the precise sculpting of mirror surfaces during polishing." The amount of research and new inventions that happens during these endeavors is what helps push modern society forward. |
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#3062 |
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Join Date: Sep 2011
Posts: 10,236
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Quote:
I wonder what this monumental discovery will do for the search for the Theory of Everything? Gravitational waves clearly aren't acting like quantum physics would predict - their existence surely suggests a smooth, continuous spacetime? Unless LIGO will carry out experiments to test any possible granularity to spacetime the signals might betray. I seem to recall an experiment a while back to test spacetime granularity failing to find any though.
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#3063 |
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Join Date: Mar 2014
Posts: 1,549
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Neil deGrasse Tyson Explains Einstein's Gravitational Waves Theory
https://www.youtube.com/watch?v=DoOPEPVYAnU Some might not like his over the top antics but you can't deny his passion for science is infectious. |
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#3064 |
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Join Date: Nov 2002
Posts: 76,816
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Quote:
Neil deGrasse Tyson Explains Einstein's Gravitational Waves Theory
https://www.youtube.com/watch?v=DoOPEPVYAnU Some might not like his over the top antics but you can't deny his passion for science is infectious. |
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#3065 |
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Join Date: Oct 2007
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Posts: 964
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To me the most surprising fact about the detection of gravity waves was in the evidence that they travelled at the speed of light. I always felt that gravitational effects would be instantaneous, acting as the surface through which light and electromagnetic waves travelled.
I suspect that dark matter/energy may turn out to be the paper upon which the universe is drawn. |
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#3066 |
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Join Date: Dec 2004
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Quote:
To me the most surprising fact about the detection of gravity waves was in the evidence that they travelled at the speed of light. I always felt that gravitational effects would be instantaneous, acting as the surface through which light and electromagnetic waves travelled.
Nor is the luminiferous ether about to make a comeback! |
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#3067 |
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#3068 |
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Apparently no one understands quantum mechanics where you can get instantaneous effects across the universe. Apparently it is information that cannot travel faster than light.
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#3069 |
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Join Date: Mar 2014
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Quote:
To me the most surprising fact about the detection of gravity waves was in the evidence that they travelled at the speed of light. I always felt that gravitational effects would be instantaneous, acting as the surface through which light and electromagnetic waves travelled.
I suspect that dark matter/energy may turn out to be the paper upon which the universe is drawn.
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#3070 |
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Join Date: Aug 2015
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And coupled with the fact that the ripple has been traveling in space for 1.3 billion years at the speed of light before it hit us. It puts into perspective just the unimaginable size of the universe. Science be cray cray.
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#3071 |
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Join Date: Mar 2014
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I think that 1.3 billion years is according to measurements in our reference frame (the earth). If you were surfing that gravitational ripple at the speed of light then it would be much much less than 1.3 billion years.
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#3072 |
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Join Date: Sep 2011
Posts: 10,236
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Quote:
Neil deGrasse Tyson Explains Einstein's Gravitational Waves Theory
https://www.youtube.com/watch?v=DoOPEPVYAnU Some might not like his over the top antics but you can't deny his passion for science is infectious. I'm not a big fan of his documentaries but here, ad libbing, he was on great form. +1I've been thinking a lot about gravitational waves and this video kind of confirmed it. LIGO was essentially a highly-advanced seismometer, but where all of the seismic data has to be removed so that we can concentrate on the 'background noise'. Considering the cacophony that their supercomputers are having to sift through it bodes very well for future space-based gravitational-wave observatories. The Hubble Space Telescope was a huge improvement over ground-based observatories, even though the atmosphere represents a relatively low-noise medium that adaptive optics can do a great job of attenuating. Even the human eye does a good job of picking stars out of the night sky. Gravitational waves on the other hand seem to be almost lost among the sounds of the Earth. The benefits of sending a GWO into orbit will be enormous. |
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#3073 |
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Join Date: Sep 2011
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Quote:
I think that 1.3 billion years is according to measurements in our reference frame (the earth). If you were surfing that gravitational ripple at the speed of light then it would be much much less than 1.3 billion years.
Quote:
Could you please explain in a little more detail what you mean?
If you were in interstellar space, for example, more time would have passed compared to that measured on Earth. And if you had been travelling along with the wave at the speed of light then no time would have seemed to have passed at all. Is that what you meant, MinaH? [Edit] It's fairly meaningless to equate light-years of distance to years of light travel, in my opinion. It completely misses the point that spacetime only conforms to human norms on human scales of space and time. It adds nothing to say, for example, that this distant collision between two black holes happened at the same time that stromatolites were the dominant lifeform on Earth, and it simply isn't true. Simultaneity, especially at such enormous distances, is an illusion. It assumes a universal 'now' that doesn't exist. |
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#3074 |
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Join Date: Dec 2004
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Quote:
[Edit] It's fairly meaningless to equate light-years of distance to years of light travel, in my opinion. It completely misses the point that spacetime only conforms to human norms on human scales of space and time. It adds nothing to say, for example, that this distant collision between two black holes happened at the same time that stromatolites were the dominant lifeform on Earth, and it simply isn't true. Simultaneity, especially at such enormous distances, is an illusion.
I understand your point about simultaneity being illusory - different celestial observers will disagree about the ordering of these events - but I don't see why this should stop us talking about what was happening on Earth (one specific location) when the gravitational waves from these two distant black holes coalescing embarked on its journey. |
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#3075 |
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WhatJoeThinks: Yes I think so. There is something called time dilation which means the faster you go the slower are your clocks relative to the "slower" reference frames. So if you were surfing the gravity wave at the speed of light you wouldn't age 1.3 billion years, I don't think you would age at all. But I am not sure you could physically be accelerated up to the speed of light only towards and close to it - so there would be some aging.
So for example super-accurate timepieces have been shown to be behind in time (running slow) after having travelled on the space shuttle or after having taken a number of trips on aircraft. So for interstellar travel - time dilation would be something relevant to take into account when estimating the ages of the spaceship occupants when arriving at various stellar systems having travelled close to the speed of light during the course of the trip. |
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