Wikipedia:Reference desk/Archives/Science/2020 April 10

= April 10 =

Do flu symptoms get worse late at night?
Is there a tendency for flu symptoms, such as nasal discharge, to get worse late at night? Freeknowledgecreator (talk) 05:21, 10 April 2020 (UTC)
 * This is known to be the case for the common cold and many other diseases; see this article in the Daily Mail. I do not know if this has been specifically observed for influenza too, but it would be more surprising if that illness was the exception. --Lambiam 06:06, 10 April 2020 (UTC)
 * I would also be interested in hearing whether COVID-19 symptoms get worse late at night. Freeknowledgecreator (talk) 06:38, 10 April 2020 (UTC)
 * The human immune system has a circadian rhythm (I assume all mammals are the same). Therefore, regardless of the trigger for the immune system, it becomes more effective at night. Much of the symtoms we feel, such as a fever, are caused by the activity of the immune system. So, you feel worse at night. Serach for "human immune system circadian rhythm" and you will find resources. 97.82.165.112 (talk) 10:54, 10 April 2020 (UTC)
 * For what it's worth, incredibly anecdotally, my COVID19 symptoms were worse at night. However, despite contacting my town board of health, doctor's office, and state department of health, at the time I was sick, the test criteria were so strict and the test available so non-existent that I was never tested. --OuroborosCobra (talk) 00:19, 11 April 2020 (UTC)

Will see you at Alpha Centauri
Coronovirus opened up a possibility to read the NYT without subscription, so I got there and saw an article: (April 7, 2020) Deceleration of Interstellar Spacecraft Utilizing Antimatter. It turned out to be an old news. Last year it appeared in Scientific American: August 5, 2019, there are even earlier publications. Article in NYT is the most interesting but I cannot reference it for obvious reason, please go there and read it. All you need is to give them your email. The shock begins at the moment you read the title (above).

This is a NASA Project. They already got some funding! The paper says: "Antimatter-based propulsion and power has emerged as a leading technology capable of enabling science missions to the exoplanet Proxima b. In stark contrast to other mission proposals involving beamed energy, this mission assumes prompt and continuous science return during the entire voyage, deceleration at Proxima Centauri," The craft is supposed to achieve ultimately 10% of the speed of light. It will be a small spacecraft, as the paper says: ten kilogramscale. The mission will begin in 2069 and last 40 years one way. A laser will be used to send messages back to earth. If they plan to decelerate it with antimatter, why not accelerate it the same way also?

Where are they going to get the antimatter? Is it realistic? To make some, the craft needs to be equipped with a particle accelerator, then perhaps a few atoms they will produced. There is no antimatter in our visible Universe. Is it just a joke?

Thanks, - AboutFace 22 (talk) 22:32, 10 April 2020 (UTC)
 * According to the article Antimatter, it is naturally occuring (in addition to coming out of particle accelerators in small amounts). RudolfRed (talk) 23:37, 10 April 2020 (UTC)
 * Antimatter propulsion is the general concept. A core problem with space travel is there's no friction in space. It takes energy to slow down just as much as to speed up. And if that's not bad enough, there are no gas stations either. Unless you can get the energy for stopping from somewhere, you have to carry it with you as some kind of fuel, which then takes more energy to accelerate at the beginning, which takes more fuel, and you can see where this is going. This is known as the "tyranny of the rocket equation". Envision driving cross-continent but towing all your fuel for the trip. This is why Breakthrough Starshot envisions a flyby—they just won't bother stopping! What you mention seems to envision accelerating the craft similarly, like with a beamed light sail, and then carrying antimatter as fuel for the stopping part. The nice thing about antimatter is it stores a lot of energy. The bad thing is storing it, since it reacts with ordinary matter. We can create it on demand in particle accelerators, as you note. Doing so is just expensive, so there's no point doing it to power your car. Some antimatter gets produced more or less continuously, mostly positrons, but it gets destroyed quickly because it finds some ordinary matter and annihilates. That's why we need special containment systems. But we inject people with antimatter-generating compounds all the time! Pretty nifty huh? --47.146.63.87 (talk) 23:48, 10 April 2020 (UTC)
 * Here's a link to the highly speculative article on the NASA TV website. I see no evidence that this idea has received funding from NASA, and the hypothetical destination is a planet around Proxima Centauri not Alpha Centauri. The Scientific American article does discuss efforts by astronomers to observe possible planets around Alpha Centauri, but I could find no discussion of interstellar spacecraft or antimatter. I am a New York Times subscriber and have searched their website every which way I can, and found no article about this topic. Of course, they have published articles about antimatter, and about interstellar travel, and have mentioned those two stars in various ways but none of those articles that I could find make the connection implied, and they were all published years or decades ago. So, something is fishy here. Can you explain, ? Cullen328  Let's discuss it  00:19, 11 April 2020 (UTC)
 * Proxima Centauri is (believed to be) part of Alpha Centauri, so that's not an error. See its article. --76.71.6.31 (talk) 02:20, 11 April 2020 (UTC)
 * Proxima Centauri is a red dwarf star which is located about .21 light years away from the Alpha Centauri binary star. That is an enormous distance away, and is about 5% of its distance from our solar system. Cullen328  Let's discuss it  02:32, 11 April 2020 (UTC)
 * True, but so is what I said. --76.71.6.31 (talk) 19:04, 11 April 2020 (UTC)

Well, I feel my honor is at stake. I don't subscribe to NYT for two reasons: too much to read with my subscription for WSJ and also I am not a liberal and spiritually it is hostile source for me, but the free access was an opportunity. I copied the paper. I have nice database for that. It is now in front of me. Probably, I found the funding mentioning in a different source, I could not find anything about it at NASA website. I remember they have been given $17M with the stipulation that there will be no more funding, that they need to find rich private donors. I think it is a highly speculative idea to begin with. Tomorrow I will find the article in the NYT. I am surprised you could not. Just google their website. Thanks, AboutFace 22 There is also this (talk) 02:29, 11 April 2020 (UTC)
 * Even if no one makes a trip to Proxima Centauri, it would be useful to be able to produce anti-matter cheaply, and to be able to store large amounts of it, and convert it into electricity or movement. Fast trips around the Solar System could become possible. If you need to have a large amount of energy in a device, but never recharge it, then this is for you. Graeme Bartlett (talk) 03:54, 11 April 2020 (UTC)

More on antimatter: how much it costs, etc. AboutFace 22 (talk) 13:51, 11 April 2020 (UTC)


 * Compress matter to a miniature black hole. This will then evaporate by Hawking radiation, the late stages of this Hawking radiation will contain electrons and positrons. You then feed this black hole with matter to prevent it from vanishing. On the long term you can then harvest vast amounts of antimatter at very low costs. Count Iblis (talk) 15:00, 11 April 2020 (UTC)
 * Black hole starship --47.146.63.87 (talk) 02:57, 12 April 2020 (UTC)