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22 Jul Pi Approximation Day
24 Jul Ask Anything Wednesday - Engineering, Mathematics, Computer science
31 Jul Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology
7 Aug Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology
14 Aug Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

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We make our world significant by the courage of our questions and by the depth of our answers. -Carl Sagan, Cosmos

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0

How do swings in the park not violate conservation of angular momentum?

The other day I went on a swing set. From a completely still position, I can pump my legs and begin swinging without ever contacting the ground. Sure, I’m expending energy, but how does this not violate conservation of angular momentum? How can I start swinging without “pushing off” something?

51 Comments
2024/07/22
09:44 UTC

108

Is the Campi Flegrei supervolcano truly preparing to erupt?

Given the recent earthquakes and quake clusters reported in the area, as well as the ground subsidence, what are the chances that Campi Flegrei is gearing up for an eruption? A super eruption? I live in Switzerland, and some of the worst case scenarios I've read about are genuinely frightening. I understand that realistic risk assessment is one of the more difficult tasks geologists and volcanologists face, but whats the buzz in the science community?

15 Comments
2024/07/21
17:30 UTC

24

What were whales like halfway through evolving back into the water?

I can't imagine an animal that's halfway between a (proto-)deer and a massive fish and can survive anywhere. That just sounds like a tasty treat to any megafauna predators.

37 Comments
2024/07/20
07:56 UTC

95

Does everyone who gets knocked out get a concussion?

37 Comments
2024/07/20
11:31 UTC

132

What is the largest discrepancy of maximum lifespan within a single species?

I have recently learned that the queens of honey bee colonies can live for several years, while most worker bees in the same colony typically only live for a few months (depending on the season, and assuming everything goes right).

That got me wondering, what other species have similar or even greater differences in lifespan within the same species? I assume this phenomenon is really only present in less complex organisms and eusocial colonies (and various dog breeds, I suppose), but I would love to be pleasantly surprised!

48 Comments
2024/07/20
09:31 UTC

0

What species of deer has the best eyesight?

I know deer have good low light vision, but poor visual clarity. Which deer species relies most on vision, or has the best distance vision/visual clarity?

4 Comments
2024/07/19
22:45 UTC

9

Is the prevalence of water-borne disease now worse than it was prior to the knowledge of boiling for disinfection? Were people just constantly getting sick from bad water?

Sort of a historical epidemiology question...

Water-borne illnesses like cholera have been part of the historical tapestry human civilization since antquity, but diseases like cholera seem to be mostly associated with water that was contaminated by filth generated by the civilization.

In modern days, it seems drinking from even fairly large rivers these days without filtration or boiling seems (anecdotally) to have a nearly 1:1 correlation with illness. Have rivers and lakes gotten dirtier or more contaminated? Have we perhaps gotten weaker as our water became increasingly sourced from wells or other cleaner sources than rivers and lakes?

8 Comments
2024/07/19
18:13 UTC

100

Does Mars smell bad?

I read this article about the Curiosity Rover rolling over a rock exposing pure elemental sulfur crystals. With potentially pure sulfur and an abundance of sulfates being present in Martian dust and rocks, it got me wondering: if we could somehow breathe/inhale on the surface of mars, would it stink?

16 Comments
2024/07/19
20:35 UTC

12

Do we know when segmented worms first colonized land?

I see plenty of references to arthrods first colonizing land in Earth's history but nothing on the worms that, for example, gave rise to Earthworms and are so essential to soil. Do we know from, say, trace fossils how early segmented worms got out of (presumably) fresh water?

1 Comment
2024/07/19
17:33 UTC

125

How long will climate change affect humanity?

I was watching a video about climate change called “why Michigan will be the best place on Earth by 2050” and in it the Author claims climate change and resulting fallout from it will be the most important and biggest event in human history affecting humanity for millennia to come. How accurate is this statement?

196 Comments
2024/07/20
03:17 UTC

119

AskScience Panel of Scientists XXVI

Please read this entire post carefully and format your application appropriately.

This post is for new panelist recruitment! The previous one is here.

The panel is an informal group of Redditors who are either professional scientists or those in training to become so. All panelists have at least a graduate-level familiarity within their declared field of expertise and answer questions from related areas of study. A panelist's expertise is summarized in a color-coded AskScience flair.

Membership in the panel comes with access to a panelist subreddit. It is a place for panelists to interact with each other, voice concerns to the moderators, and where the moderators make announcements to the whole panel. It's a good place to network with people who share your interests!

-------------------

You are eligible to join the panel if you:

  • Are studying for at least an MSc. or equivalent degree in the sciences, AND,
  • Are able to communicate your knowledge of your field at a level accessible to various audiences.

-------------------

Instructions for formatting your panelist application:

  • Choose exactly one general field from the side-bar (Physics, Engineering, Social Sciences, etc.).
  • State your specific field in one word or phrase (Neuropathology, Quantum Chemistry, etc.)
  • Succinctly describe your particular area of research in a few words (carbon nanotube dielectric properties, myelin sheath degradation in Parkinsons patients, etc.)
  • Give us a brief synopsis of your education: are you a research scientist for three decades, or a first-year Ph.D. student?
  • Provide links to comments you've made in AskScience which you feel are indicative of your scholarship. Applications will not be approved without several comments made in /r/AskScience itself.

-------------------

Ideally, these comments should clearly indicate your fluency in the fundamentals of your discipline as well as your expertise. We favor comments that contain citations so we can assess its correctness without specific domain knowledge.

Here's an example application:

Username: /u/foretopsail

General field: Anthropology

Specific field: Maritime Archaeology

Particular areas of research include historical archaeology, archaeometry, and ship construction.

Education: MA in archaeology, researcher for several years.

Comments: 1, 2, 3, 4.

Please do not give us personally identifiable information and please follow the template. We're not going to do real-life background checks - we're just asking for reddit's best behavior. However, several moderators are tasked with monitoring panelist activity, and your credentials will be checked against the academic content of your posts on a continuing basis.

You can submit your application by replying to this post.

4 Comments
2024/07/19
13:09 UTC

66

Are there other places on earth that ice sheets have "missed" over the last few ice ages of ice sheet advancement like the driftless area of the upper Mississippi valley?

10 Comments
2024/07/19
00:51 UTC

20

How much of astronomy could be rediscovered by somebody with just a telescope and camera?

Given how much of astronomy was discovered long ago before there were clocks nearly as precise or even calculators I would guess it should be possible to get a lot on your own. If you know that the Earth has an elliptical orbit and is tilted on its axis, by measuring the apparent altitude of the Sun throughout the year you could calculate the length of each day and the equation of time (I think). With a camera and telescope you could take photos throughout a year showing the changing size of the Sun to determine the eccentricity of the orbit. And so on for other factors and the Moon and planets too. Which leads to the question of how far could you get on your own. For example, I believe it should be possible to measure the synodic draconic and anomalistic months so you could get the saros cycle, but could you go further and predict where the Sun and Moon would appear to be for any given place on Earth, therefore letting you predict all eclipses, not just those in a single saros cycle (I would expect the distance to be Moon to be an important factor in this but that might be measurable by either using the distance to the Moon within a single night to vary by approximately the radius of the Earth or by having 2 people 1000s of miles apart and parallax with the stars). The time scales for other planets can be many years as opposed to a month or year for the Moon/Sun so that's why I'm not focusing on that yet.

11 Comments
2024/07/17
19:19 UTC

0

What Animal Species is Most Common?

I’ve often heard people say that beetles or other animals have more individuals than humans, and that therefore it doesn’t make sense to think of humans as the “dominant species” of earth, but I don’t think it makes sense to class all beetles together in comparison to all humans. Is there an individual species of animal with more members than humans?

23 Comments
2024/07/17
18:24 UTC

7

What is Zirconium Ceramic?

I really wasn't sure if this should be in earth science or chemistry, but I figured chemistry gets it to the state that it is used in medically and industrially. I'll try to be brief because my head hurts now.

Short version, I'm working on a story in a midevil-esque time period and metals are rare and precious in my world. So with that in mind, I don't want staple weapons that anyone is able to get ahold of to be metal because most metal only the higher class can afford. From watching too much TV and movies, I know that ceramic blades exist, mostly in the context of people using them to get a weapon past metal detectors. But ceramics is a large industry in my world, so I decided to look into it, which led me down a rabbit hole of Zirconium Ceramic products, which is all well and good but I'm trying to find out what it is and all I'm getting is technical industry jargon that I can't understand.

From what I understand, ceramic=clay. But Zirconium is metal. So metal=/=ceramic. But there is Zirconium Ceramic???

I just need a simple, clear cut, straight forward answer. Is this Zirconium mixed into clay?? Like a powdered form of it is broken down and mixed into clay which is then processed and molded into products? That's the only explanation I can think of.

20 Comments
2024/07/17
18:19 UTC

24

Was the sky a different color in the past?

I know that the sky is blue because of how the light from the sun scatters from the molecules in the atmosphere, but in the past, say during the jurassic period, was it a different color because of a different atmosphere composition or was it not different enough?

10 Comments
2024/07/17
18:03 UTC

0

Could e=mc^2 just be e=m if we used larger units for m?

E=mc^2 describes the ratio between energy and mass using our current units of energy and mass.

In a hypothetical alien culture where units for mass happened to be c^2 times larger, would they simply arrive at e=m? or is the square of the speed of light fundamentally relevant here?

Thanks!

24 Comments
2024/07/17
23:49 UTC

81

Where were the glaciers 5000 years ago?

Sorry if this has been discussed before - Reading today about how they found an ancient mining site where a glacier had receded. Also they are frequently finding man made objects in the ice where the glaciers have receded.

This makes me think that at that time the glaciers were MUCH smaller than today. But the experts say the earth is hotter now than in like 50,000 years. How can I reconcile the two things?

15 Comments
2024/07/17
21:37 UTC

2

Will voyager(s) ever collide with anything?

3 Comments
2024/07/17
22:37 UTC

128

Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Physics, Astronomy, Earth and Planetary Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here. Ask away!

113 Comments
2024/07/17
14:00 UTC

51

How are fossils uncovered in the plane of sedimentation?

We often see relatively flat fossils that have been chiseled out in the plane of the fossil. There's an excellent example here: Fossil of an ancient shark that swam in the age of dinosaurs solves centuries-long mystery | CNN. How are the fossils initially found, if they have to be chiseled out of rock before being identified or uncovered? Is there some new technology at use here, or has it always been done this way? How is the plane of the fossil identified--is it just that cracks are most likely to form in the plane of sedimentation?

8 Comments
2024/07/16
20:07 UTC

41

How does the Coriolis Effect prevent the Earth from having a single Hadley Cell?

I've been learning about Hadley Cells, and while I generally get the gist of it, the one part I don't understand is why the Coriolis Effect causes the split into 3 cells instead of just one (per hemisphere).

As I understand it, the Coriolis "force" is purely a longitudinal (east/west) effect. As such, it shouldn't have any effect on the north/south component of velocity/momentum/etc. Is this understanding just wrong?

If that is the case, then why should that prevent a mass of air from making the full trip from equator to poll, or vice versa? Sure the direction of travel becomes increasingly deflected, but the the north/south component of that velocity should be unchanged right? What does the longitudinal motion have to do with anything?

16 Comments
2024/07/16
17:09 UTC

10

Purpose of placebo arm in comparative vaccine trial?

I was wondering in layman's terms if someone can explain what the exact purpose is of the placebo injection in a comparative vaccine trial. For example (I've just made this up), there are 2 groups; one group gets, lets say meningitis vaccine in one arm and chicken pox in other arm. Now the second group gets a combination vaccine (like a 2 in 1) of meningitis and chicken pox in one arm and now placebo in the other arm. I'm having difficulty explaining this as a FAQ to patients without scaring them away. The trial is observer blinded only.

14 Comments
2024/07/15
19:42 UTC

877

AskScience AMA Series: We're the team that fixed NASA's Voyager 1 spacecraft and keeps both Voyagers flying. Ask us anything!

NASA's Voyager 1 spacecraft experienced a serious problem in November 2023 and mission leaders weren't sure they'd be able to get it working again. A failed chip in one of the onboard computers caused the spacecraft to stop sending any science or engineering data, so the team couldn't even see what was wrong. It was like trying to fix a computer with a broken screen.

But over the course of six months, a crack team of experts from around JPL brought Voyager 1 back from the brink. The task involved sorting through old documents from storage, working in a software language written in the 1970s, and lots of collaboration and teamwork. Oh, and they also had to deal with the fact that Voyager 1 is 15 billion miles (24 billion km) from Earth, which means it takes a message almost a full day to reach the spacecraft, and almost a full day for its response to come back.

Now, NASA's longest running mission can continue. Voyager 1 and its twin Voyager 2 are the only spacecraft to ever send data back from interstellar space - the space between stars. By directly sampling the particles, plasma waves, and magnetic fields in this region, scientists learn more about the Sun's protective bubble that surrounds the planets, and the ocean of material that fills most of the Milky Way galaxy.

Do you have questions for the team that performed this amazing rescue mission? Do you want to know more about what Voyager 1 is discovering in the outer region of our solar system? Meet our NASA experts from the mission who've seen it all.

We are:

  • Suzanne Dodd - Voyager Project Manager (SD)
  • Linda Spilker - Voyager Project Scientist, Voyager science team associate 1977 - 1990 (LS)
  • Dave Cummings - Voyager Tiger Team member (DC)
  • Kareem Badaruddin - Voyager Mission Manager (KB)
  • Stella Ocker - Member of the Voyager Science Steering Group at Caltech; heliophysicist (SO)
  • Bob Rasmussen - Voyager Flight Team and Tiger Team member, Voyager systems engineer ~1975-1977 (BR)

Ask us anything about:

  • What the Voyager spacecraft are discovering in the outer region of our solar system.
  • How this team recently helped fix Voyager 1.
  • The team's favorite memories or planetary encounters over the past 45+ years.

PROOF: https://twitter.com/NASA/status/1812973845529190509

We'll be online from 11:30am - 1:00pm PT (1830 - 2000 UTC) to answer your questions!

Username: u/nasa


UPDATE: That’s all the time we have for today - thank you all for your amazing questions! If you’d like to learn more about Voyager, you can visit https://voyager.jpl.nasa.gov/.

233 Comments
2024/07/16
12:48 UTC

369

Mohs Hardness Scale. Is it ever possible to scratch something harder, with something softer?

Hi,

As per title. Do below points factor into the ability of the object to scratch another object? I could never get a straight answer.

  1. Does the force applied matter?

  2. Does sharpness (edge, point) of the object matter?

85 Comments
2024/07/15
13:53 UTC

13

Curious to know what multiple layers on sides of a hill mean? Sea level was there many many years ago? Did sea level recede, or the hill kept rising up?

I saw a photo of a hill / huge rock, with multiple layers of different colours from the base to the top of it. I have read that these layers represent different eras and we get to know composition of atmosphere during those times by studying these.

However, I'm curious if this also means that hill / rock had water levels touching it? Sometimes I have seen these standalone hills in seas, and that often makes me wonder if the sea level was lower in the past, or if the rock/hill has risen above due to tectonic movements, or something else is happening?

How exactly are these layers formed?

11 Comments
2024/07/15
02:15 UTC

101

How can they determine the earth was warmer vs Greenland was located in a different place on our earth relative to the equators?

https://www.youtube.com/watch?v=P57N9p-8NdI

Around minute 5 they ask a question and the response is that the world was 10-15 degrees warmer in the distant past based on a study done in Greenland. Why can't this mean GREENLAND was 10-15 degrees warmer? How do they know that the poles weren't flipping or that Greenland was closer to the equator at the time and drifted farther from it?

10 Comments
2024/07/15
10:57 UTC

32

What is the tolerance on our globe model?

On Wikipedia the circumference of the globe is stated to the meter which is pretty accurate. I'm assuming this means we know the base featureless shape to a very high precision.

I don't know how much of the earth has been topographically mapped or if they have all been combined into one global surface model. But if we have, how accurate is it? If I were to take random samples how accurate would the height be? +- 100m? More? Less?

I feel like it depends heavily on what you define the earth's surface as. Most of the ocean isn't mapped so if we assume that the surface stops at sea level how much does that improve the accuracy?

14 Comments
2024/07/13
21:20 UTC

257

What structural modifications do 747 supertankers have to enable carrying their firefighting payload without the shifting weight affecting lift or tearing the aircraft apart from momentum?

55 Comments
2024/07/13
16:52 UTC

533

As light gets redshifted traveling long distances, does it lose energy since longer wavelengths have less energy than shorter wavelengths?

Let’s say a particle of light is moving between galaxies and has a certain amount of energy. As the universe expands, the wavelength of that light lengthens. But longer wavelengths have less energy. Would this particle then lose energy? If so, where does the energy go?

Edit: Found an article that gives a good answer to this: https://www.forbes.com/sites/startswithabang/2015/12/19/ask-ethan-when-a-photon-gets-redshifted-where-does-the-energy-go/

172 Comments
2024/07/11
14:00 UTC

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