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Saturday, April 13, 2019

How do colorblind people perceive lasers at the wavelengths they cannot see?

How do colorblind people perceive lasers at the wavelengths they cannot see?


How do colorblind people perceive lasers at the wavelengths they cannot see?

Posted: 13 Apr 2019 02:05 AM PDT

How old is the snow on top of Mt Everest?

Posted: 12 Apr 2019 11:24 AM PDT

Saw an r/Showerthoughts post earlier that talked about the snow on top of Mt Everest. This got me thinking about the lifespan of snow.

Living where I do, the Pacific North West, I think of snow as a fleeting thing, tied to a season. Lasting a few days at most. I think of how delicate snowflakes seem and imagine they can't last too long out in the wild. But then this...

Somewhere relatively undisturbed with weather conditions that suit, how long can a snowflake last? Does it just remain in that form indefinitely? Is there any way at all to tell how old snow is?

submitted by /u/pjclarke
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Has Earth had a bigger mountain than Mount Everest?

Posted: 12 Apr 2019 05:59 PM PDT

because of how Earth is constantly changing due to the crusts moving my question is has there ever been a taller mountain than mount everest that shrunk or just doesn't exist anymore?

submitted by /u/Rogocraft
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During pair production does the photon just split into a particle and antiparticle or is the photon fired at something?

Posted: 13 Apr 2019 04:18 AM PDT

Google isn't clear and my textbook just says "In pair production a photon creates a particle and a corresponding antiparticle and vanishes in the process"

submitted by /u/tryM3B1tch
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How Responsible is the Decay of Radioactive Elements for the Brightness of a Supernova?

Posted: 12 Apr 2019 03:02 PM PDT

It always seemed really clear that supernovas were bright because they were so hot and energetic, (releasing as they do more power in a few minutes as the sun will in its whole life.)

However, I recently read (in "The Magic Furnace" by Marcus Chown) that this might not be the whole story. In the 1930s, a supernova in Galaxy IC4812 was observed whose brightness cut in half every 55 days, similar to the pattern of a radioactive element with a half-life of 55 days. This led Geoffrey Burbidge to suggest that the fade of this supernovas brightness was due to the presence of recently created californium-254 (which has a 60 day half-life) decaying in the expanding shell of shock-wave.

(This was apparently later corrected and while the general idea is claimed to be correct, now scientists believe that the decaying light owes more to radioactive nickel-56 (half life of 6 days) and cobalt-56 (half life of 77 days) created during the supernova mimicking a single isotope with a half life of 60 days.)

My question is, how much of a supernova's brightness comes from traditional, 'I'd expect this from a giant explosion' sources, like heat from compression, friction, etc, and how much comes from this radioactive decay?

Thanks!

submitted by /u/HenriettaLeaveIt
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If the moon is tidally locked to Earth, how are there craters on the side facing Earth?

Posted: 12 Apr 2019 12:51 PM PDT

The Voyager pulsar map not only marks where the Earth is located, but when the Voyager probe was launched. How did we calculate this?

Posted: 12 Apr 2019 09:01 AM PDT

Pulsars make fantastic beacons because they are incredibly reliable on their pulse timing and because they can be markers not only for where in the universe something is but also when it was there. The Voyager pulsar map shows where Earth was located when the probe was launched, but how did we calculate this?

I would assume that at the time you could easily look at where the Earth is in relation to the pulsars at that moment* and just use that, but what if I wanted to make a map like that for a time long ago or long in the future?

*Did the designers of the map actually have to do more calculations than I'm postulating because the time delay in light travel skewing the relational positions? Or did they just wing it and say "that's where we see the pulsars are in relation to us factoring in delayed light, the aliens can figure that out"?

Disclosure: while I am actually very interested in hearing the answer to this, I have to admit I also have the selfish intentions of getting a Voyager pulsar map tattoo that shows where the Earth was in both time and space on my birthday.

submitted by /u/lemcott
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When the James Web telescope is launched, how much greater detail of other galaxies, or other stars should we expect to see?

Posted: 12 Apr 2019 11:15 AM PDT

How big does a meteor need to become a meteorite?

Posted: 12 Apr 2019 12:35 PM PDT

So my question is this, how big does a meteor need to be to be able to survive the transfer from outer space through our atmosphere and impact earth to the point its of notable size like the Gibeon landfall? I understand the make up of said meteor would make a difference in its resistance to breaking down as it burns through the atmosphere.

submitted by /u/Subliminal_Image
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What is the process through which charged particles deform magnetic fields?

Posted: 12 Apr 2019 06:50 PM PDT

I understand that the solar wind will deformed and break the Earth's magnetic field lines. I was wondering what the process is that causes this. I would also like to know what exactly the field lines are.

submitted by /u/Sawe871
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Why does copper sulphate crystallize in a parallelogram-like shape?

Posted: 12 Apr 2019 09:26 AM PDT

Why do worms go on top of concrete when it rains?

Posted: 12 Apr 2019 07:35 AM PDT

How and why does the brain reuptake serotonin?

Posted: 12 Apr 2019 12:45 PM PDT

Information in Regards to the Pāli Language?

Posted: 12 Apr 2019 12:34 PM PDT

Hello members of Askscience! I have a few questions about the ancient Pāli Language that I just can't seem to find any good resources which touch on them. I understand very little about this language. I know as much that it's the liturgical language of Theravada Buddhism, but I do not know much about it in terms of historical relevance and Linguistics. I am looking for any information regarding the Pāli Language but most specifically:

  • What people groups or civilizations used the Pāli language? Either as their mother tongue or a lingua franca.
  • How many speakers do we estimate spoke this language at its height?
  • Why did it die off as a spoken language?
  • What is the closest modern language that we can see influences in?
  • What linguistic features or rules of this language make it unique? E.G. Arabic (and other languages) utilize an Abjad writing system.

Any information regarding the Pāli Language is greatly appreciated, but it might be easier to compare it to other ancient languages of the time. I imagine Sanskrit and Pāli share many features and vocabulary, but this could be a sign of my lack of knowledge.

submitted by /u/grumpygator123
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Is there any singularity-free gravitational soliton? That is, is there an asymptotically (but not thoroughly) flat, static, nonsingular vacuum solution of General Relativity?

Posted: 12 Apr 2019 12:10 PM PDT

I've heard that if you replace "static" with "spherically symmetric" in the above question and ignore "singularity-free", then by Birkhoff's theorem the only such spacetime is Schwarzschild. I wonder is there a similar theorem/result that says the following: "the only static, asymptotically flat, (non-coordinate-)singularity-free metric is Minkowski flat space"?

submitted by /u/Laroel
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Does water dry quicker depending on temperature?

Posted: 12 Apr 2019 05:17 PM PDT

For example say I spilt hot water on a jumper and cold water on another jumper which one would dry faster? Would it be the cold water one because the hot water needs to cool down first? Sorry if this sounds really dumb. I have no idea what science this is- psychics maybe?

submitted by /u/libeikka
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What is the difference between BDNF & NGF?

Posted: 12 Apr 2019 11:14 AM PDT

Friday, April 12, 2019

What makes permanent and non-permanent markers different on a chemical level?

What makes permanent and non-permanent markers different on a chemical level?


What makes permanent and non-permanent markers different on a chemical level?

Posted: 11 Apr 2019 03:24 PM PDT

Can a moon have a moon? What limits the "levels" of satellite that can exist in a stable solar system?

Posted: 12 Apr 2019 12:02 AM PDT

Are the nearby airplanes cleared of the sky when launching Falcon Heavy? I was checking Flightradar24 when launch occurred and didn't see any difference. Also, 3 boosters landed back successfully. I assume the sky has to be clear of airplanes to avoid any potential collision?

Posted: 12 Apr 2019 06:27 AM PDT

Why are some roads made from concrete/cement rather than asphalt? What determines whether it should be one or the other? Why do a lot of the cement roads have grooves in them?

Posted: 11 Apr 2019 02:47 PM PDT

What is the significance of the third law of thermodynamics?

Posted: 12 Apr 2019 04:45 AM PDT

I found on the internet that the third law is defined as: "The entropy of a perfect crystal is zero when the temperature of the crystal is equal to absolute zero". I know very little about physics, so if somebody could explain, in layman terms, what this means and why it is significant that would be great.

submitted by /u/YaBoiJeff8
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Do ants have sleep/wake cycles?

Posted: 12 Apr 2019 12:17 AM PDT

Do ants have sleep/wake cycles? If so, how do they compare to human sleep cycles? Do they have various stages like we do?

submitted by /u/Howyadoing129
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How fast do materials cool off in space? What's the most significant process that cools them?

Posted: 12 Apr 2019 01:04 AM PDT

I know the answer is "it depends", but I'm still curious about specific examples like what drives water to cool and how fast does it happen? Or, what causes living things to cool in space in space and how fast does that happen? Im sure you get the gist.

submitted by /u/overtheridge
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Why are focal seizures more likely to start in the temporal lobe than in other lobes?

Posted: 12 Apr 2019 07:06 AM PDT

How CRT TV controls the beams so quickly back in the old days?

Posted: 12 Apr 2019 03:02 AM PDT

Unlike LED where each pixel has a light source, a CRT relies on just 1 set of cathode ray tube (for color tvs that has 3 color beams). I understand the control of the beam directions done by a set of magnetic coils, however even for very old B&W TV's, it would still require not just precision but super human speed to point the light at the correct spots. To do so with a modern circuit would be easy, but how did they achieve such speed & accuracy back then when even electronic calculators did not exist?

also any reason no manufacturer tried to use more sets of cathode ray for higher resolution and faster refresh rate?

submitted by /u/burningbun
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Is it possible to simultaneously get an extra chromosome from one parent and miss out on that chromosome from the other? If so, would the resulting child have any defects?

Posted: 11 Apr 2019 01:49 PM PDT

To clarify, the end result would be both chromosomes coming from the same parent.

submitted by /u/LadonLegend
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Are facial expressions genetic or are they “learned” by social cues?

Posted: 11 Apr 2019 07:52 PM PDT

For example, do humans instinctively know how to facially express disgust at birth/without external influences or do they learn the expression by watching others?

submitted by /u/mrmanmanmanmanbob
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When I delete a gigabyte of music from my phone, what happens to that information?

Posted: 11 Apr 2019 08:52 PM PDT

If hot air rises, why are high mountains so cold?

Posted: 11 Apr 2019 04:32 PM PDT

I just have been wondering, if warm air rises, why are mountains cold? Shouldn't all the warm air be up there? Yet, some mountains have snow at the tops, even in summer. Can anyone explain this to me?

submitted by /u/TheOne1ThatGotAway
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Why is M-Theory incompatible with the E-8 lattice?

Posted: 12 Apr 2019 01:09 AM PDT

As far as I understand M-Theory, it's the best existing extrapolation of String Theory, bringing together all other exclusive string theories. I recently heard about the E-8 lattice and find it to be an elegant solution to the question of everything, but it surprises me that it's considered completely incomparable with string theory. Is it just the maths, or is there something more fundamentally incompatible between the two theories of everything?

edit: sp

submitted by /u/ZeF_TyM
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How can we take pictures of the sun?

Posted: 11 Apr 2019 02:18 PM PDT

Looking at the sun causes retina damage, and you can start a fire with a magnifying glass. How can we use lenses that focus light to take a picture onto film without it burning the film or damaging the camera?

submitted by /u/mossotti58
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What do the words "measurment" or "observation" mean in the context of quantum physics?

Posted: 11 Apr 2019 09:23 AM PDT

More specifically, what do they mean in the context of the uncertainty principle, double slit experiment, or entangled particles?

submitted by /u/Heptagonalhippo
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How far back in time could you go before natural wonders such as Uluru or the Grand Canyon are unrecognizable? Are there any examples of natural features which have developed over the span of human history?

Posted: 11 Apr 2019 11:42 AM PDT

What exactly are the cores In processors and how are they made?

Posted: 11 Apr 2019 06:14 PM PDT

I'm a computer geek but have never really seen anything about computer cores besides what they do and etc. I'm really curious as to what the really are and how they are made. Also if you would kindly why can't the process of making them get any smaller such as 7nm etc.

submitted by /u/jakerb2028
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Are some languages more difficult for people with dyslexia?

Posted: 11 Apr 2019 11:51 PM PDT

I don't have dyslexia. But I know it is something like seeing letters not as we see them, or at least mixing them up. Now I was wondering if it's more difficult in other writings, for example Asian languages or Arabic? Because for me those characters seem more complex than our alphabet. For example, is Chinese as a native language also more difficult for Chinese speaking people with dyslexia?

submitted by /u/KristofDSa
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What happens to the blood vessels going to the hand if you lose the hand?

Posted: 11 Apr 2019 01:08 PM PDT

If your hand is removed, there should still be blood vessels in the wrist that used to go into the hand. Do they stay there and you just have dead ends to your blood vessels after your stump heals, does your body "shut down" those vessels, do they get redirected, or am I completely off base?

submitted by /u/wildrose4everrr
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Why did we have to send a probe to Pluto to get a photo of it?

Posted: 11 Apr 2019 04:09 PM PDT

So this week scientists released a photo of a black hole in a whole other galaxy. What I want to know is why do we have all these fancy telescopes that can photograph objects in galaxies so far away yet if we want to get a photo of a planet in our own solar system we have to send a satellite/probe to do it?

submitted by /u/MurgaReddit
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Thursday, April 11, 2019

Was there a scientific reason behind the decision to take a picture of this particular black hole instead of another one ?

Was there a scientific reason behind the decision to take a picture of this particular black hole instead of another one ?


Was there a scientific reason behind the decision to take a picture of this particular black hole instead of another one ?

Posted: 10 Apr 2019 10:57 PM PDT

I wondered why did they "elected" this one instead of a closer one for instance? Thank you

submitted by /u/Gethisa
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How would an array of Space Telescopes work?

Posted: 11 Apr 2019 01:24 AM PDT

The image of the Black Hole this week was made possible by connecting many ground-based radio telescopes, making an 'aperture' the width of our planet. What I wonder is; could a constellation of space radio-telescopes connect to make the 'aperture' larger, even solar system sized? Also, would increasing the number of satellites in the constellation increase the resolution of the image?

submitted by /u/BGDDisco
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Black Hole Megathread: Day 2. Ask all black hole questions here

Posted: 11 Apr 2019 07:20 AM PDT

If you didn't see the fantastic AMA yesterday with the Event Horizon Telescope team, be sure to check it out. If you have any further questions, you can ask them here and our many expert panelists will come answer. While it's always nice to have a Q&A discussion, be sure to utilize out FAQ, the search function, and google as well.

submitted by /u/iorgfeflkd
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Do animals get muscle knots the same way humans do?

Posted: 11 Apr 2019 08:18 AM PDT

Are brain development timelines consistent across cultures?

Posted: 11 Apr 2019 08:08 AM PDT

I always hear how the prefrontal cortex (responsible for logical thought process/understanding long term consequences) isn't fully developed until age 25ish. What I wonder is if this has been checked in cultures where kids are given more responsibilities at younger ages than in the USA. Like is the development of the prefrontal cortex(and the rest of the brain) something that happens on a rough timeline like crawling and walking. Or is it developed through having life experience and receiving consequences from actions? Therefore, it develops later in the USA where kids aren't given many freedoms or responsibilities.

submitted by /u/UniqueUsername718
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How far back in time could you go before 'natural wonders' such as the Grand Canyon or Uluru? Are there any unique features which have developed over the span of human history?

Posted: 11 Apr 2019 08:07 AM PDT

How effective is our ability to detect incoming, disaster-causing asteroids/meteors?

Posted: 11 Apr 2019 05:16 AM PDT

Could there be something extinction-causing on its way to us that we wouldn't know about until it's practically right on top of us? Just curious.

submitted by /u/Scymitar
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Is the Schwarzschildradius of a black hole dependent on local curvature of spacetime at the observer's position?

Posted: 11 Apr 2019 04:17 AM PDT

So I think I have a pretty decent grasp of general relativity. For a long time I had problems reconciling the relatively weak gravitational forces experienced for an observer in a frame near the event horizon of a supermassive black hole in particular with the nature of the event horizon being this hard boundary that information cannot pass.

I think I managed to solve that in my mind, knowing that the distance from the event horizon is observer dependent. Here's a thought experiment to illustrate what I think is happening:

Consider you and a friend are at a "sufficient" distance (100,000 AU) from a black hole's event horizon (r = 1 AU) so that you are currently in only very slightly curved spacetime. Now you decide to move forward 100,000.1 AU (from your original frame) while your friend stays behind. You are now at a distance closer to the singularity than you originally perceived the event horizon to be, but you still see the event horizon being some distance away from you. You now shine a laser at your previous position. The light beam does pass the initially perceived boundary but never reaches your friend and curves back. Meanwhile, your friend will never see you passing past the 100,000 AU mark and will never see you shine the laser.

I understand that the initial "decision" to move forward 100,000.1 AU is kind of flawed as the distance you travel is dependent on the frame you're in and that shifts as you move closer to the black hole.

My questions are this:
- Is my assumption correct that you can knowingly move past the location of the event horizon you perceived from the initial resting frame and in your new frame still send information somewhat outside of that original boundary, just not all the way back to the initial frame?

- Will your new position cause you to perceive a smaller schwarzschildradius than you did initially, or will it have the same radius, i.e. is the calculated schwarzschildradius just an upper bound for the radius perceived by a distant observer or is it observer invariant?

submitted by /u/searingsky
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It is said that we tend to forget memories that aren't recalled often or not used often, if so then how come traumatic memories stay vivid even after decades of experiencing them?

Posted: 11 Apr 2019 06:29 AM PDT

What factors affect the distribution of our taste buds and what flavors we enjoy? Are there genetics factors? Is it all about what you’re exposed to? What causes our tastes in food to change as we age?

Posted: 11 Apr 2019 06:18 AM PDT

How long do water filters in our fridge actually last and what are the negatives of using one for an extended period of time?

Posted: 10 Apr 2019 12:45 PM PDT

I've had the same water filter in my brita filter for more than a year now, but have never noticed a difference and the water tastes clean. Also as a bonus question, how does it even work?

submitted by /u/Chemicald90
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Can we produce energy from gravitational waves that catching by LIGO?

Posted: 11 Apr 2019 01:31 AM PDT

I read an article:LIGO has spotted another gravitational wave just after turning back on

A quote from article:

Now that the twin detectors in Livingston, Louisiana, and Hanford, Washington, have been upgraded, we expect to see about one set of gravitational waves per week

And this gave me a question. Can we produce energy from gravitational waves that catching by LIGO? If can we, is it possible be a new form of renewable energy?

submitted by /u/selmansamet
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With the new picture of a black hole, is there now any doubt or opposing evidence that black holes exist?

Posted: 10 Apr 2019 03:32 PM PDT

How do platypuses digest food without a stomach that creates acid?

Posted: 10 Apr 2019 04:19 PM PDT

This is a repost, but in the original thread there was only one reply, and it got deleted.

submitted by /u/qazqaz3
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Why is the melting point of D-amphetamine so high?

Posted: 10 Apr 2019 08:38 PM PDT

Trying to find out why the melting point of dexamphetamine sulphate is so low, yet D-amphetamine is around 300 degrees. Thankyou for any replies

submitted by /u/Millenilol
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How Does Sound Combine to be Louder?

Posted: 10 Apr 2019 01:49 PM PDT

Example: One person yelling at the top of their lungs is loud when close-up, but take 10000 people yelling at the same volume and it becomes deafening and audible from a long distance.

What is the science of sound combining and becoming more powerful?

submitted by /u/sneaky291
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Is it likely there are planets with geostationary moons? Would they have a perpetual eclipse in one area?

Posted: 10 Apr 2019 01:51 PM PDT

What is the science behind bread rising?

Posted: 10 Apr 2019 05:38 PM PDT

Why do telescopes and cameras use light instead of measuring other particles/waves such as sound or radio waves to form an image?

Posted: 10 Apr 2019 11:12 AM PDT

After seeing the EHT pictures of the black hole released this morning, I have been thinking about other methods which we could use to capture images (similar to thermal vision which measures heat and produces an image). One idea would be using radio waves to to sort of map out the bottom of the ocean where there is no light because of the depth. Is something like this realistic or already done or is there no way to form images out of radio/sound waves in a usable way?

submitted by /u/Sassafratch
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Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 10 Apr 2019 08:15 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer 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!

submitted by /u/AutoModerator
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At what point does a star cluster become a galaxy?

Posted: 10 Apr 2019 10:37 AM PDT