Cycling UK Forum

Where's Manc33 when we need him?

sjs wrote:Where's Manc33 when we need him?

Probably crying into his unobtainium...

Actually, major experimental triumph it may be, but as far as the advancement of human knowledge goes, I don't believe there's any big deal in this grav wave stuff. As long as we believe in General Relativity (and physicists have been believing in it for 100 years now), we know they are out there somewhere, their discovery doesn't change anything. It's when we hear of an unexpected discovery (like those faster-than-light neutrinos* - that turned out to be spurious) that we ought to sit up and take notice.

Actually the first experimental 'proof' of GR was demonstrated by Eddington back in 1919, with his eclipse observations showing that light was 'bent' under the influence of gravity. Except that he didn't actually prove anything. With a few assumptions, his results could have been explained under Newtonian physics as well as Einsteinian. And anyway, some modern astronomers think his observations were too inaccurate to 'prove' anything at all. Ah well! At least Eddington left us with the 'Eddington Number' - which is of considerably more interest to cyclists!

But since then other experimental observations - such as the precise orbit of Mercury - have given more credence to Einstein. I think we (pace Manc33 and a few others...) can take his work as proven, now.

*which reminds me:
BARMAN: sorry we don't serve your sort, in here.
NEUTRINO: A pint of bitter please.
A neutrino walks into a bar....

661-Pete wrote:his results could have been explained under Newtonian physics as well as Einsteinian.

Could they? How?
(Not being funny, just curious. I'd have thought that since photons have no mass then Newtonian physics wouldn't apply. If that's true then bending light due to gravity can only occur if space time is distorted...)

kwackers wrote:

661-Pete wrote:his results could have been explained under Newtonian physics as well as Einsteinian.

Could they? How?
(Not being funny, just curious. I'd have thought that since photons have no mass then Newtonian physics wouldn't apply. If that's true then bending light due to gravity can only occur if space time is distorted...)

I should have made it clearer: under Newton's law of gravity (F = Gm1m2/R²) coupled with a crude application of Einstein's Special relativity, light bends under gravity. Because - as every schoolboy knows - E = mc² blah blah blah hence photons have mass proportional to their energy. They have no rest mass but they can't be brought to a standstill anyway.

Special Relativity and General Relativity are two very different things. One is (relatively [ba-doom!]) easy, the other is bloody hard!

661-Pete wrote:Actually, major experimental triumph it may be, but as far as the advancement of human knowledge goes, I don't believe there's any big deal in this grav wave stuff. As long as we believe in General Relativity (and physicists have been believing in it for 100 years now), we know they are out there somewhere, their discovery doesn't change anything. It's when we hear of an unexpected discovery (like those faster-than-light neutrinos* - that turned out to be spurious) that we ought to sit up and take notice.

Ye-e-e-es... Trouble is that before confirmation it remains belief, however strong, so it's that much gained. And the mood now is that further LIGO-style observatories will be worth building, since gravity waves offer another means of studying the universe.

It doesn't hurt physics, either, to have such a feat as this to shove under the noses of the bean-counters.

661-Pete wrote:Because - as every schoolboy knows - E = mc² blah blah blah hence photons have mass proportional to their energy. They have no rest mass but they can't be brought to a standstill anyway.

I never thought of that! Cheers.

661-Pete wrote:

kwackers wrote:

661-Pete wrote:his results could have been explained under Newtonian physics as well as Einsteinian.

Could they? How?
(Not being funny, just curious. I'd have thought that since photons have no mass then Newtonian physics wouldn't apply. If that's true then bending light due to gravity can only occur if space time is distorted...)

I should have made it clearer: under Newton's law of gravity (F = Gm1m2/R²) coupled with a crude application of Einstein's Special relativity, light bends under gravity. Because - as every schoolboy knows - E = mc² blah blah blah hence photons have mass proportional to their energy. They have no rest mass but they can't be brought to a standstill anyway.

Special Relativity and General Relativity are two very different things. One is (relatively [ba-doom!]) easy, the other is bloody hard!

But under Newtonian physics, no one thought of gravity affecting light. We needed Einstein's persepctive to understand it that way. Maybe physics was ripe for the concept, and it would have happened without Einstein, but it is only in hindsight that we can (kind of) explain it in Newtonian terms.

661-Pete wrote:Actually, major experimental triumph it may be, but as far as the advancement of human knowledge goes, I don't believe there's any big deal in this grav wave stuff....

(I think of) establishing that gravity waves exist (and thus demonstrating an aspect of General Relativity) is only one aspect of the work. To date astronomical observation has pretty well been restricted to electromagnetic waves. Now we have something else. LIGO was tuned to a fairly narrow frequency range. So we can start looking at more of what is going on and where, etc. not dependent on electromagnetic waves. Build more sensitive detectors ...

I see it as a means to discover more about the Universe and the confirming General Relativity is (to me) nice, but the future potential is exciting.

Ian

661-Pete wrote:But since then other experimental observations - such as the precise orbit of Mercury - have given more credence to Einstein. I think we (pace Manc33 and a few others...) can take his work as proven, now.

Proven? No. Even Newton's theory isn't proven, just substantiated. We use it as if it has been proven, in almost everything we design and build, because it works. But it could still be disproven someday. It's more likely, however, that we will find something else to modify or update it.

There may come another theory to overlay Einstein's like Einstein's overlay Newtons.

Vorpal wrote:

661-Pete wrote:But since then other experimental observations - such as the precise orbit of Mercury - have given more credence to Einstein. I think we (pace Manc33 and a few others...) can take his work as proven, now.

Proven? No. Even Newton's theory isn't proven, just substantiated. We use it as if it has been proven, in almost everything we design and build, because it works. But it could still be disproven someday. It's more likely, however, that we will find something else to modify or update it.

There may come another theory to overlay Einstein's like Einstein's overlay Newtons.

I agree - but you're beginning to sound like friend Manc ....

Just to note that this experiment is a further endorsement of General Relativity but the theory is already pretty well supported without needing bending light and gravity waves. For example without Special and General Relativity built into it your GPS would npt work.

GPS requires nanosecond timing precision between orbiting satellites and the ground. Special Relativity corrections from the orbiting clocks running 7 microseconds a day slower due to SR time dilation from their relative motion and a GR correction of 45 microseconds a day faster because they are in a lower gravity and therefore less curved space-time region mean a 38 microsecond a day Relativity correction overall. Thats a daily correctiin of 38,000 times the required timing accuracy. Relativity in practical daily use in our cycling lives.

^^^ and all we need is a good coronal mass ejection to be back in the age of the sextant.

People were quoting Neil DeGrasse Tyson when he said:

"We have yet to detect a gravity wave"

So they chose to "discover" gravity waves.

How scientific!

Meanwhile other scientists are debunking the findings and saying that the people claiming the victory are just after grant money - which sounds a lot more like what humans would do (even in science).

Science is corrupted, as fantastic as that might sound.

At one time you used your own senses and that was science in its purest form (and it still is) but those days are long gone. Now you're told everything by "experts" with their "theoretical" this and "theoretical" that.

One example is you're told Earth rotates on an axis, yet the Earth doesn't move and nothing can prove it does. Another example is we get told Earth is a ball shape, yet nothing proves it and things can be seen over the ocean for 149 miles easily disproving it. Mountain ranges aren't curving away in the distance and so on, its all there if you use your own senses but, who does... they would much rather get into an endless argument about the math and so on, which means nothing if we can observe differently in the real world.

Manc33 wrote:One example is you're told Earth rotates on an axis, yet the Earth doesn't move and nothing can prove it does. Another example is we get told Earth is a ball shape, yet nothing proves it and things can be seen over the ocean for 149 miles easily disproving it. Mountain ranges aren't curving away in the distance and so on, its all there if you use your own senses but, who does... they would much rather get into an endless argument about the math and so on, which means nothing if we can observe differently in the real world.

Well, when it becomes possible to buy a ticket into space, you can go and see it for yourself