Wikipedia:Reference desk/Archives/Science/2019 October 8

= October 8 =

chem
how do you find the number of protons neutrons and electrons, in a negative oxygen with atomic mass 16 and atomic number 18? -- Thegooduser  Life Begins With a Smile :)  🍁 02:09, 8 October 2019 (UTC)
 * What is a negative oxygen? ←Baseball Bugs What's up, Doc? carrots→ 03:18, 8 October 2019 (UTC)


 * I am guessing they mean a negatively charged ion, which would mean more electrons than protons. But we need to know exactly how much negative charge to determine how many extra electrons it has. Oxygen has an atomic number 8, not 18, so maybe he refers to an ionized molecule ? Hydrogen peroxide (H2O2) has a total of 18 protons (in other words, the total of the atomic numbers is 18). But the atomic weight of 16 makes no sense, as the atomic weight should be equal or more than the atomic number. For hydrogen peroxide the total atomic weight is about 34, since that's the total of the protons and neutrons (and a tiny bit for electrons). So, I can't make any sense of those figures.


 * For a single atom with an atomic number of 18, that would be argon, but it has an atomic mass of 36-42, depending on isotope. SinisterLefty (talk) 03:30, 8 October 2019 (UTC)


 * All isotopes of oxygen always have 8 protons, regardless of their atomic mass number. oxygen-18 has 18 mass, including those 8 protons, the number of neutrons is 18-8=10. The number of electron will the same as the number of protons, plus any negative charge; for instance, 9 for for O- Gem fr (talk) 08:56, 9 October 2019 (UTC)

Lights on the ocean at night
When flying in Southeast Asia recently, I saw what looked like lights on the surface of the ocean at night, and I can't figure out what they could be. I saw them over the Java Sea (coordinates about -5, 110) and over the South China Sea (about 20, 114). Are they ships? But if so, why are they so uniform? They're all the same color, the same brightness, and spread fairly uniformly over a certain area, not clustered. In the picture you can see a few, but over the Java Sea I saw what looked like hundreds. —Granger (talk · contribs) 11:28, 8 October 2019 (UTC)


 * They are probably fishing boats with lights used to "attract squid and other sea life", as in this image from NASA. Mikenorton (talk) 11:53, 8 October 2019 (UTC)

2019 Nobel Prize in Physics
I just read in the Wall Street Journal that the Prize had been awarded to 3 scientists. The article is very vague but it seems that the first one, James Peebles from Princeton, is a theoretician. What is his contribution? Thanks, - AboutFace 22 (talk) 15:07, 8 October 2019 (UTC)


 * This BBC story goes into more detail. Mikenorton (talk) 15:21, 8 October 2019 (UTC)


 * (ec) Our Jim Peebles article says he made "major theoretical contributions to primordial nucleosynthesis, dark matter, the cosmic microwave background, and structure formation". However, I'm not sure which of those the prize was for. SinisterLefty (talk) 15:23, 8 October 2019 (UTC)

The Wikipedia's article about him, quoted above, says: "he expressed a preferred reference frame for velocity anywhere in the universe based on Isotropic Cosmic Background Radiation, a departure from previous models." What does it mean? I think the CMB is anisotropic. AboutFace 22 (talk) 17:46, 8 October 2019 (UTC)
 * See Cosmic_microwave_background. On the one hand, Lorentz symmetry implies the laws of physics are unaffected by an observer's motion; on the other hand the CMB data implies a rest frame through which the earth moves at 368 ±2 km/s causing the CMB to appear slightly red-shifted in the direction of movement. DroneB (talk) 15:26, 9 October 2019 (UTC)
 * It's a preferred reference frame in the same way that the walls of the room that you're in present a preferred reference frame (the one where these walls are at rest). It's just convenient for describing the actual Universe that we live in. It does not break and has nothing to do with Lorentz symmetry. --Wrongfilter (talk) 07:27, 10 October 2019 (UTC)