Recent comments in /f/askscience

ShadowEllipse t1_j4ugvce wrote

Reply to comment by Erratic_Noman in Biologically speaking, what makes men typically stronger than women? by Erratic_Noman

The structure of muscles are the same but you have more amounts of it on men, although ofc testosterone is super potent on muscle buildup so unless women get huge amounts of this, they can't build as much muscle as a man. Testosterone is produced in a small amounts in women but not that much.

TLDR: Built different.

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wakatenai OP t1_j4uf3x2 wrote

Reply to comment by die_kuestenwache in would exposing an individual to infection on a regular basis make their immune system stronger than normal? by wakatenai

thanks for the reply.

I'm fully vaccinated and understand that vaccines are the best defense we can create, but i was still curious to ask if your immune system can enhance general defenses.

does getting a specific virus multiple times have the same effect as multiple vaccines? like the cold, if I ha the cold 100 times would my immune system be better at fighting future colds? more than someone who has maybe only had 20? assuming I had the same strain 100 times that is.

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B0ssTato t1_j4ue2yu wrote

Reply to How do waterfalls freeze? by THE_WARDEN3036

Normally, the molecules in the waterfall move under the influence of both the flow and thermal agitation. But if it gets cold enough, the heat effect becomes so low that not even the waterfall's motion can stop ice forming, gradually at first but then ever more rapidly.

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matteogeniaccio t1_j4ucyvr wrote

Reply to Is a black hole a virtual object? by peacefultoker420

Yes and no. A black hole is defined as the volume behind the event horizon, the "point of no return".
The event horizon is not a physical surface, you only have its definition: you wouldn't know it's a point of no return unless you waited for an infinite amount of time. A good approximation of the event horizon is the surface where the escape velocity is the speed of light.

Nevertheless, black holes are real objects. Their gravity has effects on the outside world. They are created by a stellar collapse. They can orbit around another massive astronomical object.

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die_kuestenwache t1_j4ucsz6 wrote

Reply to would exposing an individual to infection on a regular basis make their immune system stronger than normal? by wakatenai

Afaik, no. Your immune system develops antibodies that are more or less pathogenspecific. Since you are not interested in vaccination, which would be the effect for the pathogen you are using, this would not make your immune system better at fighting other pathogens. But you would likely develop scarring, and eventually, the regions of the skin you are treating may develop rashes and heal less effectively.

You can not generally train your immune system in this way. Getting the flue does not lower your chance of contracting malaria. Any stress, healing wounds and fighting diseases included, weakens your immune response.

If there is other information out there I'd be interested to know as well.

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BobbyP27 t1_j4u9of0 wrote

Reply to comment by icbmike_for_realz in Extinction of the Dinosaurs: What did I miss? by cakedayCountdown

Large explosive volcanic eruptions can pump enough particulate matter into the high atmosphere to interrupt weather patterns. One of the largest in recent history, the eruption of Mount Tambora in 1815, for example, caused the "year without summer", and a number of similar eruptions happened earlier in recorded history where we did not, at the time, know the source, but have since discovered the locations. We know from geological evidence, far far larger volcanic eruptions and events have taken place, and an event on such a scale could cause sufficient particulate matter to enter the atmosphere that it could create a period of several years of insufficient sunlight reaching the surface of the earth to massively disrupt ecosystems and create a mass extinction event. There is geological evidence that one such event, in the Deccan Traps of modern day India took place at the right sort of time (on a geological scale) and was large enough that it is a plausible candidate for causing the extinction event that ended the dinosaurs.

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sometimesgoodadvice t1_j4u9hi1 wrote

Reply to I have just been told that A, tests markers for blood tests and health checks etc (I dunno… testosterone, cholesterol, red blood cells) in the population are changing over time, and that B, the acceptable levels for such markers are changing with them. Is this true? by rsbanham

Really not sure about the premise and how much normal ranges actually change. Let's make an assumption that it is true thought and use some logic. What defines a normal range for a given biomarker? Let's say I was a really good scientist and wanted to do "better science" to find out what a healthy range for red blood cell count was. I would probably take a cross-section of people that doctors have called "healthy" and ones that they have diagnosed with a disease that affects RBC. Then I would do some nice statistics and say that 95% of people with with disease corresponding to low RBC had counts <3e12L and 95% of people with disease that correspond to elevated RBC had counts of >7e12/L. So I will define my "healthy" range as 3-7e12/L show that that corresponds to 98% of "healthy" people. Then I do some more statistics to determine false positive and negative rates, teach doctors how and when to properly utilize this knowledge (including performing the test exactly as I had) and be done.

There really is not a different way to do this. There is no equation that can tell you how many RB cells you need to have. There are some limits of upper and lower bounds, but those are not very useful, so we have to be empirical.

Now let's say I do this again, 50 years later and find that the value shifted. Is there a big problem? After all, the healthy range still corresponds to people that are "healthy" and the unhealthy range to those that have some underlying condition that doctors can diagnose. Maybe the range shifted because people in general have become "unhealthy". But then they would be diagnosed as such. It's just as likely that the range shifted because fewer people are eating lead paint, or because we decided to include people from diverse backgrounds with different genetics or environmental stimuli that were not available in the first study. Maybe the range shifted because people are much "healthier" now with more monitoring and resources available to stay healthy. As long as the range serves its purpose - identifying values that are indicative of an underlying disease - it does not matter what the absolute value is.

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sheismagic4e t1_j4u83oi wrote

Reply to Biologically speaking, what makes men typically stronger than women? by Erratic_Noman

Evolutionary Design: Men are built to hunt and protect, while woman play the major role in reproduction and care taking of the next generation. This diversification happens during puberty and needs to be seen in context. It does not mean women can't be stronger than man, but at the extremes its quite clear , see top level sports.

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