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Quote from: hamdani yusuf on 13/01/2023 12:29:18because you said this about Dalton's model.I know I said that.So what?
because you said this about Dalton's model.
Quote from: Bored chemist on 14/01/2023 11:14:11Quote from: hamdani yusuf on 13/01/2023 12:29:18because you said this about Dalton's model.I know I said that.So what?When did pre-scientific age stop?
interference & diffraction...gravitational wave
Murray Dunn says, “Is there anything that can absorb, reflect or refract gravitational waves? Or do they propagate undisturbed until the end of time?” Well, gravitational waves interact with matter, they do, just like electromagnetic waves do, I shouldn’t say just like, but not exactly just like.0:53:41.2 SC: The crucially, crucially important difference, and I’ve emphasized this in many different contexts is that in electromagnetism, you have positive charges and negative charges. And by subtly mixing up the configuration of the positive charges and negative charges, you can basically create or cancel out any electromagnetic field you want. In particular, you can absorb or reflect, okay? Whereas gravitational charges are just the masses of the particles that you’re making up your system from, and those are always positive. Gravity is always attractive, there’s no repulsive gravitational force between two ordinary particles.0:54:17.2 SC: And so it is enormously harder to manipulate gravitational waves, that plus, of course, the fact that gravity is just a really weak force, so that also makes it very, very hard. So therefore, to a really good approximation, gravitational waves just propagate undisturbed until the end of time. They will, of course, be deflected by other gravitational fields. There’s gravitational lensing of gravitational waves, but reflecting them is almost impossible to do because they will lose energy. As a gravitational wave passes through a cloud of gas or whatever, it exerts energy on the cloud and therefore loses energy itself, but that effect is super duper really tiny. It’s not one that you really have to take into account as a working astronomer.
- Interference (black spots in a light field) occurs because electromagnetism has positive and negative charges- The Electric field of Electromagnetic radiation (eg light) oscillates positive and negative (electromagnetic radiation is a bipolar wave).- Where positive polarity coincides with negative polarity, you get interference and "black spots" (if the amplitude is equal)
I really hope he didn't say that
Quote from: hamdani yusuf on 14/01/2023 11:16:23Quote from: Bored chemist on 14/01/2023 11:14:11Quote from: hamdani yusuf on 13/01/2023 12:29:18because you said this about Dalton's model.I know I said that.So what?When did pre-scientific age stop?It doesn't matter unless it was "thousands of years" ago.Any idea that was believed for thousands of years (whether it was right or wrong) wasn't scientific.Science is commonly said to have started around 1600 with people like Francis Bacon.
However, gravitational fields have only positive masses, so you don't get positives & negatives in gravitational waves (gravitational waves are a quadripolar wave).- I presume from this that gravitational waves are extremely unlikely to produce cancellation? (maybe impossible?)- But diffraction is certainly possible.
The air pressure at any point in the room is always positive. Yet we can still observe interference effect.
What's your reason to set that time frame?
Archimedes made some scientific discoveries.
Newton made some unscientific assertions.
But you can’t reverse gravitational mass, so I interpreted this as saying that if you have two sources of gravitational waves, they are unlikely to cancel.
"Old fashioned textbooks of optics have separate chaptersfor ‘interference’ and ‘diffraction’. But this distinctionis artificial. "Fromhttps://www.ias.ac.in/article/fulltext/reso/020/05/0389-0400
Diffraction refers to light not traveling in a straight line and bending into the shadow. It was observed by Grimaldi in Italy in the 17th century. Newton also studied diffraction and tried, unsuccessfully, to explain it in terms of his ‘corpuscles’ (particles) of light.
How can you say that it's the same as interference?
Quote from: hamdani yusuf on 15/01/2023 17:39:38What's your reason to set that time frame?How did you come to the conclusion that I had set the time frame?Quote from: hamdani yusuf on 15/01/2023 17:39:38Archimedes made some scientific discoveries.Like what?I mean, I know he made some discoveries but which ones relied on this?https://en.wikipedia.org/wiki/Scientific_method
James Gregory (1638–1675) observed the diffraction patterns caused by a bird feather, which was effectively the first diffraction grating (in a natural form) to be discovered, about a year after Isaac Newton's prism experiments.[8] The first man-made diffraction grating was made around 1785 by Philadelphia inventor David Rittenhouse, who strung hairs between two finely threaded screws.[9][10] This was similar to notable German physicist Joseph von Fraunhofer's wire diffraction grating in 1821.[11][12] The principles of diffraction were discovered by Thomas Young[13] and Augustin-Jean Fresnel.[14][15] Using these principles, Fraunhofer was the first who used a diffraction grating to obtain line spectra and the first who measured the wavelengths of spectral lines with a diffraction grating.https://en.wikipedia.org/wiki/Diffraction_grating
Figure 2. Depictions of top-down view of diffraction grating showing groove pattern (left, top) and side view showing different groove profiles (left, bottom). Scanning electron microscope image of diffraction grating (right).https://www.newport.com/n/diffraction-grating-physics
Quote from: Bored chemist on 15/01/2023 21:28:00Quote from: hamdani yusuf on 15/01/2023 17:39:38What's your reason to set that time frame?How did you come to the conclusion that I had set the time frame?Quote from: hamdani yusuf on 15/01/2023 17:39:38Archimedes made some scientific discoveries.Like what?I mean, I know he made some discoveries but which ones relied on this?https://en.wikipedia.org/wiki/Scientific_methodPlease answer the questions.
"As regards his method, Aristotle is recognized as the inventor of scientific method because of his refined analysis of logical implications contained in demonstrative discourse, which goes well beyond natural logic and does not owe anything to the ones who philosophized before him." – Riccardo Pozzo[10]
Ibn al-Haytham (965–1039). A polymath, considered by some to be the father of modern scientific methodology, due to his emphasis on experimental data and reproducibility of its results.[11][12][13]
Quote from: hamdani yusuf on 17/01/2023 06:26:05How can you say that it's the same as interference?Because the thing that causes the light to bend is interference.
The simplest problem is diffraction by a single straight edge, regarded as infinite
This was studied experimentally by the French physicist A Fresnel, around 1810. He was able to give a theory for the phenomenon. The resulting intensity distribution is shown in Figure 2. The pattern of intensity on the wall is similar at different distances, but the size of the pattern increases as the square root of the distance from the screen
Fresnel’s theory is based on Huygens’ idea that every point on a wavefront acts as a source of ‘secondary waves’. It is sketched in Figure 3a and outlined in Box 1. This theory was very successful in explaining the early experiments. However, the idea of secondary waves raises many questions. Why should a wave itself act as a sourceof secondary waves? Why do we not include the secondary wave traveling in the backward direction from a given wavefront?
Around the same time, Young in England gave a different formulation in which the original wave falling on the screen travels unaltered into the region accessible to rays, An additional wave originates from the edge of the aperture, and enters the geometric shadow (Figure 3b). It might appear impossible to reconcile these two points of view, as different as the English and the French nations! Young did not give a mathematical formulation. Maggi (1890) and Sommerfeld’s student Rubinowicz (1912) were able to show the equivalence of these two very different looking pictures. When the expression given by the Fresnel theory was transformed using integration by parts, it precisely gave rise to the Young edge wave!
As regards his method, Aristotle is recognized as the inventor of scientific method because of his refined analysis of logical implications contained in demonstrative discourse