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

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June 5

Can releasing dragonflies cure malaria?

Would reproducing large numbers of dragonflies and releasing them into malaria-prone regions be sufficient to eradicate malaria and other vector-borne illnesses where the vector is mosquitoes? 2620:101:F000:740:D513:5A1F:346C:96F4 (talk) 01:01, 5 June 2019 (UTC)

Reduce, possibly. Eradicate, probably not. If a predator species were to entirely eliminate one of its prey species (which implies that it would at least severely reduce its other prey species as well) it would itself suffer a severe population crash if not local extinction. Predator-prey balances usually reach an equilibrium well short of eliminating the latter. Also, ecosystems are complex, and entirely eliminating even a human disease-carrying species might have unforseen deleterious consequences. {The poster formerly known as 87.81.230.195} 2.122.177.55 (talk) 02:02, 5 June 2019 (UTC)

An introduced species can completely eliminate a native species, especially if it also hunts other species, so can maintain its numbers even when the targeted species' numbers drop. If the predator was a native species, though, the target would presumably have evolved a method of survival (periodical cicadas have an interesting one). SinisterLefty (talk) 02:36, 5 June 2019 (UTC)

Dragonflies don't eat just mosquitoes, and chances are they would drive pretty much everything near extinction before mosquitoes. At which point, they will die out and mosquitoes recover faster than anything, and may even end more numerous than before. Look at predatory-prey relation and Competitive Lotka–Volterra equations

So, the short answer is: No. Gem fr (talk) 06:24, 5 June 2019 (UTC)

This has some interesting stuff about eradicating malaria. https://interestingengineering.com/fungus-modified-to-produce-spider-venom-that-could-be-used-to-kill-malaria-carrying-mosquitoes 196.213.35.147 (talk) 07:54, 5 June 2019 (UTC)

malaria has links to all fighting techniques. Besides, just like cancer, climate change, fuel scarcity etc., malaria tend to attract nutty "look, my favorite useless thing could be use to fight it" claims. Gem fr (talk) 09:48, 5 June 2019 (UTC)

DDT worked pretty well, but it had some side effects. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:39, 5 June 2019 (UTC)

WOW. What a splendid idea ... teach a fungus how to make one of the deadliest toxins in the world, then release mosquitoes exposed to it in a large area. But don't worry, the fungus will never make it through a double layer of mosquito netting... surely, granted extraordinary power to kill, it will never expand its host range, nor share its WMD knowledge with any other organism... what could possibly go wrong? Wnt (talk) 14:26, 5 June 2019 (UTC)

Thanks for the LOL (well, the matter IS serious, you made it funny)Gem fr (talk) 16:21, 5 June 2019 (UTC)

A pesticide analogy to ice-9. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:33, 5 June 2019 (UTC)

Because of the relative masses of a human versus a mosquito, the venom would have to be at something like a million times the concentration in the mosquito of what it would be in the human it injected ([1]), and then only if all the venom was injected. So, unless the human has an extreme allergy, such a low concentration shouldn't even be detectable. SinisterLefty (talk) 15:34, 5 June 2019 (UTC)

I hadn't been thinking so much of being bitten by the mosquito as being infected by the fungus. It only kills insects now, but if it now has a much-improved ability to kill other organisms (not necessarily large at first) then it should have the opportunity to evolve to make use of their corpses. Wnt (talk) 05:53, 6 June 2019 (UTC)

On further examination (i.e. asking my beloved Alexandra Elbakyan her opinion about https://science.sciencemag.org/content/364/6443/894.full ), also seeing some extra information at [2], it appears that the scheme is not quite as lunatic as I first thought. The toxin in question is omega/kappa hexatoxin Hv1a, which appears to be a small peptide with limited homology to the kind that is dangerous to humans, and is described only by citation to [3] (where it is one of several tested), which cites [4] which links structure [5] and thereby the amino acid sequence SPTCIPSGQPCPYNENCCSQSCTFKENENGNTVKRCD . The stability of the cysteine knot motif is described in this paper. You can argue that such a little scrap of data isn't going to affect humans even with some mutations (though it has structural homology, not much sequence homology, to human toxins), and I'd hope you're right, which may limit the risk more toward other insects. I am, however, still skeptical that funnel-web spiders evolved their toxin to kill malaria mosquitoes, and wonder how many amino acids would need to change for it to affect more organisms. Wnt (talk) 08:56, 7 June 2019 (UTC)

This reminds me of this theoretical analysis of engineered killer mosquitoes. They don't mention it in the paper, but they did make an unsuccessful attempt to actually engineer this into fruit flies. As to the original question, I honestly don't see anything wrong with it, except that "to extinction" is unlikely. Consider the sterile insect technique, where trillions of factory-bred sterilized males are released into the environment to overwhelm the local females with useless mating partners. If you had a predator of a pest species, and you could cheaply breed that predator on an industrial scale, so what if it eats the entire prey population? Good. I mean, if the predators are highly specialized, they just die out; and if they're not, but you sterilized them before they were released, the damage is limited until their lifespans run out; and if you didn't, but the prey are not native to this environment, they might just freeze to death in winter or something; and if none of that is true, okay, you have a new invasive predator population that's going to mess with the food chain. But then again, people have been so eager to eliminate some pests that they drained wetlands and bathed nations in insecticides, honestly believing any damage to the environment was worth it. I like to compare to that before deciding that something has an unacceptable cost or risk to the environment. Someguy1221 (talk) 23:04, 7 June 2019 (UTC)

Einstein's theories of relativity

What do Einstein's general and special theories of relativity state, in layman's terms? I've tried to understand them on my own by reading about them, but they're incredibly complicated to me. EonLinE (talk) 15:32, 5 June 2019 (UTC)

There's a lot to it, such as the time dilation near the speed of light, but as a practical matter, perhaps E=mc² is the most applicable to daily life. That says that energy and mass can be converted into each other, such as in a nuclear reactor or bomb, where some of the mass is converted into a huge amount of energy. SinisterLefty (talk) 15:39, 5 June 2019 (UTC)

I just see NO possible "layman's terms" for these theories. That are reasons why they are taught after extensive training in math and physics. Nobody knows that there WERE theories of physics (inherited from, basically, Aristotle) before Newton: we just have no need of them in the curriculum and it was much simpler to skip them altogether and go straight to Newton's. If the same could have been done (skipping Newton and going straight to Einstein), it would.

well, I do see some "layman's terms" for these theories, but I don't see how those will help you in any way. for instance: the universe is curved by the mass of things; so the light is always going in straight line; and gravitation is not about an attraction (distance effect) but rather a straight movement in a curved universe (local effect). Now, figuring a curved universe, where mass IS curvature...

May be you could try this http://www.savoir-sans-frontieres.com/JPP/telechargeables/English/everything_is_relative.htm ?

Gem fr (talk) 16:15, 5 June 2019 (UTC)

You can try Relativity for the Layman. Ruslik_Zero 19:21, 5 June 2019 (UTC)

The basic principles are actually fairly simple, though they're easier to grasp if you have some knowledge of classical mechanics. From our theory of relativity article, special relativity is based on just two axioms:

1. The laws of physics are the same for all observers in uniform motion relative to one another (principle of relativity).
2. The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the light source.

General relativity is based upon Einstein's equivalence principle: that being in a gravitational field is equivalent to being under acceleration. The "force" of gravity arises because mass and energy curve spacetime when present, and anything in that spacetime is compelled to follow the resulting geometry. All the predictions of relativity arise from just applying these principles. For more detail I recommend these videos on relativity from PBS Space Time (that channel is great for physics in general). --47.146.63.87 (talk) 19:48, 5 June 2019 (UTC)

Also, I'll link our introduction to general relativity just in case you didn't find it. --47.146.63.87 (talk) 02:58, 6 June 2019 (UTC)

In layman's terms, Special Relativity is stating the various consequences of the fact that light is measured to have the same speed no matter how fast you or the light source are moving (unlike say, a car on the highway, which seems to be getting closer or further from you at a rate that depends on your own speed), as well as the fact that basic the laws of physics you experience (think Newton and Maxwell) don't seem to change with how fast you are moving. General relativity is stating the various consequences of, basically, that plus gravity. In terms of equations, the special relativistic maths are mostly used to describe how things you observe seem to change depending on how fast they are moving relative to you. And the equations of general relativity define a relationship between the shape of spacetime on one side of the equation, and the stuff it contains on the other side (matter and energy). The shape of spacetime also defines how the stuff contained by spacetime moves and changes, which then dictates how the shape changes, so this becomes a continuous dynamic relationship. Basically, it lets a physicist predict how matter and energy move around over time, and how spacetime changes over time. These equations are absolute triumphs of what you can predict from a handful of assumptions, but they are not easy to understand. Someguy1221 (talk) 19:54, 5 June 2019 (UTC)

In lamyman's terms: you know how in olden days, people believed the Earth was flat like a pancake (i.e. 2 dimensional), but later they realized it was round like a ball (i.e. we still live on a 2-d surface, but it's a curved surface embedded in 3-d space)? Relativity is the same thing. We used to think space was 3-dimensional (flat and infinite in all directions), and the distance between two points was the Euclidean distance, the one you get from the Pythagorean theorem (sqrt(x^2+y^2+z^2)). Special relatively says no, we actually live in 4-dimensional spacetime, and the interval between two points uses the Minkowski metric t^2-x^2-y^2-z^2. Notice because of the subtractions, the whole thing can be less than zero if the space distance is large and the time interval is small. That isn't allowed to happen which means it's impossible to move faster than light.

General relativity says that 4-d spacetime is itself curved, and the curvature happens in places where mass is present, and gravity results from this curvature. By computing the curvature you can show effects like time dilation around massive objects like the Sun,o r even more extreme, around black holes. For a long time physicists calculated Newtonian predictions of the planet Mercury's orbit (using its distance from the Sun, the Sun's mass, etc.), and astronomers observed the orbit with telescopes and kept seeing a small discrepancy between the physicists' calculations and the actual orbit. GR was able to explain the discrepancy and how to compute it, and that was a big success that helped GR get accepted as a theory (see "perihelion of Mercury" section of tests of General Relativity).

You might like the old book Mr Tompkins in Wonderland which is about a guy entering a world where relativistic effects are big enough to be experienced in real life. 173.228.123.207 (talk) 20:48, 5 June 2019 (UTC)

• A good book for the layperson was written by Einstein himself: Relativity: The Special and the General Theory, Wings Books, 1961 translation. Loraof (talk) 21:20, 6 June 2019 (UTC)

While there is a lot of data involved, and many bi-product effects of it, the very very layman explanation is that there is a proportional relationship between matter and energy in the universe.

Electron Configuration

Determine whether the following electronic configurations are correct and explain your answer.

a. 1s22s32p63s1
b. 1s22s22p53s1 

69.127.67.181 (talk) 15:41, 5 June 2019 (UTC)

We won't do your homework for you, but if you show us your answer, we might comment on it. SinisterLefty (talk) 15:50, 5 June 2019 (UTC)

Collapsing: drama far out of proportion of the initiating event. TigraanClick here to contact me 17:04, 6 June 2019 (UTC)

And it wouldn't hurt if you were to ask instead of issuing an order. ←Baseball Bugs What's up, Doc? carrots→ 16:49, 5 June 2019 (UTC) the poster was simply stating the question he/she had been posed. No need to be hostile about it, or rabbit on further.80.2.20.209 (talk) 23:14, 5 June 2019 (UTC) Hostility leads to more hostility. ←Baseball Bugs What's up, Doc? carrots→ 00:16, 6 June 2019 (UTC) it seems you are looking for an argument?80.2.20.209 (talk) 01:29, 6 June 2019 (UTC) No it isn't. ←Baseball Bugs What's up, Doc? carrots→ 02:36, 6 June 2019 (UTC) Using imperative or demanding verbs "Determine!" "Explain!" is appropriate for issuing military orders, exercising authority or imposing an exam task (likely the case here) but is a jarring way to request free help from volunteers. The comment by Baseball Bugs was apt and needs no debate that can only distract from the good answers by Graeme Bartlett and Wnt. DroneB (talk) 13:05, 6 June 2019 (UTC) WP:BITE? — Preceding unsigned comment added by 86.8.201.163 (talk) 00:25, 7 June 2019 (UTC)

Our article on this topic is Electron configuration. Graeme Bartlett (talk) 23:05, 5 June 2019 (UTC)

How many electrons fit in an s orbital? Can you fit more? How many electrons fit in the three p orbitals (x, y, z)? Can you fit less? That gets your answer. Note electrons can only fit in a single orbital together if they have opposite spins. Also, electrons can be "promoted" to a more energetic orbital by absorbing a photon. Wnt (talk) 11:12, 6 June 2019 (UTC)

ELECTRONS do not exist in orbials. ELECTRONS are pure energy. ELECTRONS may be given more energy, but that does not give them a larger radius of orbit. ELECTRONS do not orbit the nucleus. Otherwise they would emit em radiation. ELECTRONS are space charge existing some where remote from the nucleus. 86.8.201.182 (talk) 22:43, 7 June 2019 (UTC)

You aret confusing orbital with orbit. Electrons most certainly do have particle-like nature...they are not just photons. DMacks (talk) 03:38, 8 June 2019 (UTC)

And electrons aren't pure energy, in that they do have a (very light) rest mass. SinisterLefty (talk) 08:20, 8 June 2019 (UTC)

Does Diet Coke or Pepsi cause cancer

Does Diet Coke or Pepsi cause cancer due to aspartame or the coloring in the products — Preceding unsigned comment added by 64.222.180.90 (talk) 17:45, 5 June 2019 (UTC)

Our "aspartame" and "caramel color" (I assume that's the coloring additive) articles have substantial sections about the safety of these substances, with cites to reliable sources for further reading. DMacks (talk) 17:56, 5 June 2019 (UTC)

Quantum Encryption

In the WSJ of today there is a two page spread: "The Race to Save Encryption." by Christopher Mims. I am not sure he is in a position to understand the subject but this is what he says. The encryption algorithms of today that run on conventional computers may be made so complicated that only quantum computers might decrypt them. The latter could be made much-much smaller. There is an international race to develop a QC with China at the forefront and US and Russia trying to catch up. The development of QC might take at least 10 years or perhaps 20 or 30.

From what I carried away from reading on the matter in the past it seems that quantum communication is inherently safe and cannot be broken, I mean the messages cannot be intersected and understood, and they do not need any additional encryption. The author does not go into this subject at all. Could anybody shed light on the issue?

Thanks AboutFace 22 (talk) 19:05, 5 June 2019 (UTC)

I suggest that you read quantum cryptography. Ruslik_Zero 19:13, 5 June 2019 (UTC)

Quantum_computing#Cryptography is a lighter read. Tigraan^{Click here to contact me} 17:21, 6 June 2019 (UTC)

Pretty sure your suspicion about Mims is correct. Someguy1221 (talk) 23:43, 5 June 2019 (UTC)

• There are two "quantum" issues that are closely related in their consequences but not so much related in their causes.

The first is whether current algorithms are "safe" against quantum computing. RSA is a widespread cryptography system and relies on the fact that integer factorization is much much harder than integer multiplication; however, it is not so with a quantum computer; same thing for a lot (all?) implementations of a Diffie–Hellman key exchange. The only saving grace for today's banking system, internet HTTPS connections etc. etc. is that making a quantum computer is hard, and has not been yet achieved (at least officially) at scales that allow integer factorization.

The second is about quantum-based cryptography. It turns out that commercial systems already exist that allow for communication of random data with no interception possible during transmission. The idea is that you share a random secret key on a channel whose physical properties guarantee that an interception attempt will be detected, and thereafter use that secret key for regular communication, changing it regularly. While a passive listener on the network cannot break that encryption (barring a seismic change in physics of far greater importance than finding a polynomial-time integer factorization algorithm), which is already huge, it does not mean it is entirely foolproof - if your computer is bugged, or if the random number generator that creates the key is compromised, then all bets are off. Tigraan^{Click here to contact me} 17:21, 6 June 2019 (UTC)

Entropy

What was the entropy the universe at the time of the big bang?. And has it increased or decreased in a linear fashion since then? Can we decrease entropy in the universe? If not, could it be zero at big bang time. 80.2.20.145 (talk) 22:33, 5 June 2019 (UTC)

It was very low at the start, the minimum. Entropy has increased since then. Take a look at The Entropy of the Universe and the Maximum Entropy Production Principle by Charles H. Lineweaver Graeme Bartlett (talk) 23:04, 5 June 2019 (UTC)

Origins

If our universe just created itself out of nothing and expanded into a nothingness that didnt exist yet as 'space' , then why can't other universes sprout up out of nothing as well? If these other universes can exist, then they must exist. So, if they exist, where are they hiding? Why can't we see them?80.2.20.209 (talk) 23:37, 5 June 2019 (UTC)

See Multiverse. If they existed and interacted with us, then presumably we would not exit. See also anthropic principle. One theory is that the big bang is a brane collision between two such "regions" -- Ekpyrotic universe. Graeme Bartlett (talk) 00:08, 6 June 2019 (UTC)

that's just the very definition of a "universe": if it can (or even just could) be seen by us, interact with us in any way (gravitation, for instance), it is part of the very same universe we belong, not part of another. Is it is part of another universe, there is no way we can "see" (physically interact) it. So, for every purpose, other universes, if any, just don't exist as far as we are concerned.

also, be aware that metaphysics allows things to be unique. For instance, in mathematics there is only ONE real line; it does have many ways to appear (to be constructed by mathematicians), but it is always the same good old real line, with no "other real line" hiding anywhere. So the fact that one exists is no proof that other all exist. Gem fr (talk) 05:33, 6 June 2019 (UTC)

Math does sometimes hint at hidden worlds. For example, the square root of 9 is typically considered to be 3, but another answer is -3. That's fairly obvious, but roots can also be complex numbers, which sometimes relate to the real world, but often do not, at least not in any apparent way. SinisterLefty (talk) 22:27, 6 June 2019 (UTC)

False vacuum might be relevant where anthropic principle is concerned. The linguistics are less interesting: other galaxies used to be called "island universes" in the old days. There will always be a temptation, when one's definition of the universe expands, to choose between logic and habit for what the term applies to; but it doesn't affect what's out there. Wnt (talk) 14:34, 7 June 2019 (UTC)

Each instant of time a new Universe. Count Iblis (talk) 20:37, 9 June 2019 (UTC)