Wikipedia:Reference desk/Archives/Science/2019 January 5

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January 5

Species identification

There's a picture I need to add a caption to, identifying the species in the pic. What kind of hummingbirds are these?

Please provide link(s). Thank you.    — The Transhumanist   01:33, 5 January 2019 (UTC)

Another one...

What kind of hummingbird is this?    — The Transhumanist   01:36, 5 January 2019 (UTC)

There could be three species in those photos. Abductive (reasoning) 01:45, 5 January 2019 (UTC)

For the first picture, of the two in New Mexico, I'm not sure we can see the birds clearly enough to identify them. I found a list of NM hummingbirds (with pictures) here. For the one on the left, all I can really make out for certain is the iridescent green on the back. There are multiple species in NM to have this, including the Broad-tailed hummingbird and Ruby-throated hummingbird (and probably others; please check through the list). According to that site, neither is very common in NM, though our article confirms that the broad-tail at least passes through while on migration. The picture was taken in May, though, which doesn't seem to be when they migrate. Sorry, maybe someone else can do better.

For the bird from San Fran, I think it's a Rufous hummingbird. Matt Deres (talk) 15:54, 5 January 2019 (UTC)

FYI, I've converted your images to thumbnails so they'd sit more easily on the page; I'm not sure why you'd set them as banners instead of thumbnails, but it was distracting. Matt Deres (talk) 19:07, 5 January 2019 (UTC)

I was looking at the articles about, and they say that the broad-tailed hummingbird has a white eye ring that can be used in identification, which I think I see in the first image. The article shows a summer range including much of New Mexico as I would interpret the graphic. Our article on Rufous hummingbird says that it is very difficult to distinguish from Allen's hummingbird and it might come down to exactly where and when the picture was taken. Wnt (talk) 14:03, 7 January 2019 (UTC)

Good point. I thought the tail was diagnostic, but I guess not. Unfortunately, the photo is only dated as "2006", so there's no saying whether it was summertime or not. Maybe the blooms would lend a clue? If they're not typically open while Allen's is there, that would support my proposal of Rufous. Matt Deres (talk) 21:21, 7 January 2019 (UTC)

Can organic chemistry reactions be calculated on a computer?

I've seen computer-generated videos showing what happens in some of these complex organic chemistry reactions, but can computers actually calculate what is happening? Computational chemistry doesn't say anything about organic chem. Bubba73 ^{You talkin' to me?} 08:39, 5 January 2019 (UTC)

3D-Visualisation of a Photosynthetic reaction centre (cytochrome subunit)

If you count PET/CT-Systems as computers, they can even be set up to track marked molecules in a body in realtime and that way track and measure biological processes in a living organism. Computers are also frequently used in fields like Process simulation or Chemical reaction engineering or simply as a 3D-Visualisation to understand more complex molecules or find key structures faster. Beyond that i doubt computers are successful in finding anything meaningful with purpose beyond their search pattern or to put it more precise realize when they find something special. --Kharon (talk) 16:44, 5 January 2019 (UTC)

I'm mainly asking about using physics to calculate how organic chemistry reactions work. Bubba73 ^{You talkin' to me?} 18:34, 5 January 2019 (UTC)

Like Folding@Home? Sagittarian Milky Way (talk) 19:35, 5 January 2019 (UTC)

Yes, I think that counts. Bubba73 ^{You talkin' to me?} 01:16, 6 January 2019 (UTC)

Tetrahydrocannabinol

Chemistry and especially Biochemistry or organic chemistry gets to complicated to fast and unpredictable if and how it interacts with other chemicals. Just compare the famous 2 drug Tetrahydrocannabinol THC and Cannabidiol CBD, which are a) almost identical and b)still very small molecules but they cause totally different effects in organisms and influence each others effects. A few years ago a study found CBD may be a Antidepressant[1].

If you could calculate even reactions of simple molecules, we would probably have drugs and medicine for every known illness and for future ones aswell today. Unfortunately we cant, not even with that very promising project Folding@Home that Sagittarian Milky Way thankfully linked. But nomatter its impressive 135 petaFLOPS calculation power apparently the best it manages to do is find "interesting Candidates" that have to be further evaluated by scientists for their potential.

So no. Computers cant calculate organic chemistry. Even with the power of a big commercial data center they need years to sort gazillions of possible combinations of molecules and their possible 3D structures for a "hey that one looks interresting". --Kharon (talk) 01:24, 6 January 2019 (UTC)

I'm not talking about calculating their effect, it is more about how the molecules operate on the molecular level, like DNA reproducing would be an example (probably one of the more complicated ones). Bubba73 ^{You talkin' to me?} 02:09, 6 January 2019 (UTC)

The level of sophistication I'm seeing here doesn't greatly impress me with its accuracy. But I don't know this area of research and I could be missing better efforts. Wnt (talk) 02:07, 6 January 2019 (UTC)

I am not an expert in computational chemistry, but Derek Lowe (chemist) writes a blog that is pretty accessible to people with a but of technical knowledge. Here is his archive of computational chemistry articles: [2] In the years that I have been reading his blog, my general understanding is that computation chemistry has come a long way, but that real systems are very complicated and that calculated results are often different from real world results. shoy (reactions) 15:07, 10 January 2019 (UTC)

Astronomer vs. astrophysicist

It seems to me that more and more the general public is calling astronomers "astrophysicist". To name one, J. Allen Hynek - in the introduction he is listed as an astronomer but in the box to the right he is listed as an astrophysicist. He sounds like an astronomer to me. (I could name others.) Is this distinction getting blurred? Bubba73 ^{You talkin' to me?} 18:41, 5 January 2019 (UTC)

I think that in the twentieth and twenty-first centuries the distinction is probably one of self-identification by the scientist. Astronomy, by etymology, is the description of the stars. In early modern times it came to be the description of the telescopic observation of the planets and stars, first by Galileo and then by others. In the eighteenth and nineteenth centuries, after Newton showed that universal gravitation accounted for the orbital Kepler ellipses, astrophysics was the mathematical analysis of the orbits of the planets. In the twentieth and twenty-first centuries, astrophysics also includes the nuclear physics of what goes on inside the stars. Robert McClenon (talk) 20:04, 5 January 2019 (UTC)

In the case of amateurs, they are more likely to be called astronomers, especially if their research does not involve physics. They have long played a role of astronomy because of their willingness to spend time in observation. TFD (talk) 20:57, 5 January 2019 (UTC)

I had two astronomy teachers in college. One's research was in the interior of stars. I had him for celestial mechanics, and other things. Definitely an astrophysicist. The other's research was in observing galactic structure. He would be an astronomer in my mind. Bubba73 ^{You talkin' to me?} 21:32, 5 January 2019 (UTC)

I think that is the distinction people make, but it is becoming less distinct. As I remember, astronomy as the subject was called was part of the physics department and completion of the course fulfilled any requirements for high school physics. (That is if a course required prior completion of high school physics, then it was waived upon completion of an astronomy course. But there was also a separate "gee wiz" astronomy course that did not involve physics and did not count as a physics prerequisite.) TFD (talk) 01:21, 6 January 2019 (UTC)

Traditionally an astronomer was someone who named the stars -- observed what was in the sky. But now nobody reports that they "spotted a speck of light" at such and such a location; they have to try to explain what it is. And just explaining what it is involves things like Hubble's law and emission and absorption bands and if they are observing an orbital period and so on. So my feeling is that there is a lot of physics in any modern astronomy. Wnt (talk) 02:14, 6 January 2019 (UTC)