When I saw the title I was like "This is so obvious, any 3 year old knows it" After a minute of starting watching it, I was like "Shit, I don't know shit"

@michaelunderhill5497

8 жыл бұрын

XD Same

@paolopatron5411

7 жыл бұрын

More like "lol I know this stuff" then he goes "actually, it's not that, there's this other explanation" then when I go "ohhh that makes sense" he goes "actually, that's not it either, here's another explanation" then he does this three more times

yes, inject the knowledge into my veins!

@gangstermedia9039

7 жыл бұрын

Bullshit knowledge

@invertedgames7993

7 жыл бұрын

Ian Last replied

@hazri8758

4 жыл бұрын

@@tomascanevaro4292 you really love streotyping people I see

@ishworshrestha3559

4 жыл бұрын

Ol

@oshiriz6486

3 жыл бұрын

.

Vsauce, Minutephysics, Periodic videos..... An incredible and unbelievable playlist for the weekend :)

@raykent3211

9 жыл бұрын

You might like to add Sixty Symbols for next weekend (I'm a fan)

@vesteel

9 жыл бұрын

Matheus Bitencourt and numberphile, Minuteearth and CGP Grey?

@GeekyStuffVerified

8 жыл бұрын

:)

@yuichilee96

8 жыл бұрын

+Matheus Bitencourt SciShow, Crashcourse and Veritasium?

@aishwaryasriram7371

8 жыл бұрын

ASAPscience!!

The answer is obvious, its dark so you can sleep better.

@LossOfEternal

8 жыл бұрын

Lol

@Titanic-wo6bq

8 жыл бұрын

Y Y Y Y Y Y

@Yottifferent

7 жыл бұрын

Bizmarkk i am reading this commment at 10 pm

@condor07usa

7 жыл бұрын

not true for people who live near arctic poles

@user-kx6gr6ky4b

6 жыл бұрын

Bismarck that's so true man👍

SO if aliens are observing us they see a dinosaur?

@InvokingPeace

10 жыл бұрын

pretty much

@ghostlourde2700

10 жыл бұрын

Unless we figure out how to time travel. then they might see us looking at the dinosaurs. or perhaps we time travel to stop ourselves from time travelling, 1 + -1 style.

@gabepatton9851

10 жыл бұрын

***** Although, because of the motion of the Galaxy/Solar System/Earth, time travel would have to include some way to account for literally everything in the universe, as well as a way to get to the earth to actually see it during that time, instead of just the point in space that earth is in the time you're travelling from. Furthermore, we would have to measure the speed and direction of everything in the universe also, to find where it was/will be or else we run the risk of traveling to a time during which the place that you are now was in fact occupied by some asteroid. This would likely result in the destruction of what is known as you, as all of the electrons/neutrons/protons that you are made up of would be scrambled among those that made up said asteroid, and this would cause the creation of new particles as all of the electrons ... etc mixed and combined in ways that neither your bod nor the asteroid had them in before. Basically, time travel would be extremely dangerous without a dizzying amount of math.

@keithvrotsos3843

10 жыл бұрын

That appears to be the train of logic implied... so I guess.

@MaxoRedstoneo

10 жыл бұрын

i think, as far as i know

I asked this question in my 8th grade science class. My teacher didn't have an answer. A few years later I asked my dad. We thought about it and this is the answer we came up with. I am so excited this video exists because I've been asking this question for years. Thank you.

shouldn't ultraviolet and x-ray light from ultra-distant stars get redshifted into the visible spectrum?

@sodr7440

4 жыл бұрын

Oh yes ????

@sodr7440

4 жыл бұрын

May be there is a lot less ultraviolet light than infrared? so when they redshift to visible spectrum, they remain not intense enough for us to be able to see it

@mikethespike056

4 жыл бұрын

Wow

@kenivia9476

4 жыл бұрын

probably would just look like a normal star to naked eyes tho cos they must be like super distant

@dreamyrhodes

4 жыл бұрын

It does. The quasars we see from almost 13 b light years away are radiating heavily in the UV and X-Ray spectrum but we still see them all red. And the backgound light is shifted even more, into microwaves. That's why the cosmic background is a microwave background which equals a temperature of 3.15 K or -270°C so all the light from the big bang reaches us as 3 K radiation.

Videos like this are the reason why I LOVE physics 💚 Thankyou for the great work! continue doing so :)

This is a lot better than the 10 second videos.

i am even more confused after i finished watching this vid, sos

@yjk92

8 жыл бұрын

Well, you know a lightyear is the amount of distance light travels in one year, right? So if you look at a star 1 lightyear away, you get the image of the star with 1 year delay, since the light you just got started traveling 1 year ago. if a new star popped up 2 million years ago, but the distance between this star and our Earth is 1 million lightyears, we still need to wait 1 million more years for that light(the image of the star) to arrive. That is why we can't see a lot of stars that certainly exist. Light is so slow that it takes time to reach us. Also many stars' light is out of our visible spectrum. Kinda like how some animals can hear sound that is too high or low for humans to hear, there are light that only machines can see.

@Newstory737

7 жыл бұрын

Light is fast I believe.. Just the space between the star and our planet seems to be very, very big :)

@yes12337

7 жыл бұрын

light is a wave, yes? So then imagine throwing a stone in the Pacific Ocean and waiting to see the wave on the coast of Europe.

@gabrielbrady1471

7 жыл бұрын

the reason its dark is because the universe is infinitely large and growing that the light from the big bang hasn't reached us yet but when it does the night sky will be light if that makes any sense to you if it don't forget everything that I just said

@samihaislam3487

7 жыл бұрын

Infrared radiation is outside of our visible limit. Humans cannot see it.

One of the best videos I have ever seen. This channel is so wonderful. Great job!

This is the only channel which gives me answers about cosmos without giving me existential dread

This was amazing. I never really got a reason to admire astronomy but this is a great one, thanks! :)

Love these to the point explanations!!!

2:26 is not to scale children!

@MSpacer

10 жыл бұрын

Well, duh.

@brendarojas5613

4 жыл бұрын

Humans aren't as tall as Earth???

Very nice, I've always been wondering at this question and this perfectly explains it

I want infrared vision :(

@SreenikethanI

5 жыл бұрын

But you'll see every object on earth glowing eerily like hell

@iammaybeasliceofpie4674

5 жыл бұрын

Become a bee!

@ricardoalves9605

5 жыл бұрын

haiggoh The atmosphere would absorve the infrared coming from the sky And everything would glow

@missingpatel7349

4 жыл бұрын

Infrared vision is good. But the question is... how much infrared?

@leoroastkarega3753

3 жыл бұрын

Buy infrared binoculars

This is almost unbearably beautiful. Thanks!

this was both educational and strangely adorable, thank you!!

I can't believe I never knew what the term "infrared" actually meant until now.

@ricochet188

8 жыл бұрын

I got that from the video. Thankyou.

@rescuecatHQ

8 жыл бұрын

***** so what is microwaves?

@pyramidblack

8 жыл бұрын

+Julien12150 thanks wiki

@Sontraid

8 жыл бұрын

Is there a wavelength higher then 1 meter? Like 2 meter or even a kilometer?

@pyramidblack

8 жыл бұрын

+Sontraid 10 m is decimeters but its rarely used 100 is hektometers and 1000 is kilometers

Yes. I saw a picture sometime (an artist's rendition I think, or maybe a simulation) that basically measured the strength and wavelength detection of the creature's (I think it was a lizard or chameleon of some kind) eyes and then took a picture of the night sky with those wavelengths, combined it with visible light (I think it sees in the spectrum we see, along with infrared) and vuala. You'd have to do some searching for it, but if I remember the article right, that sums it up.

Hold on a second! Wouldn't the redshifting get the ultraviolet radiation from distant stars and galaxies into the visible spectrum in a similar way? So what's going on there?

@muthukumaranl

5 жыл бұрын

i have the same doubt too..

@passthebutterrobot2600

5 жыл бұрын

That's a very good point! Anyone know?

@deadat2

5 жыл бұрын

Well sure it's just that the range of visible is fairly small Red700nm-violet400nm. Redhift is just the measurement of the change in wave length of light that say a hydrogen atom emits divided by it's rest wavelength. So really the question is kind of irrelevant with the scales we are talking about anything close enough to be in the visible spectrum is to close to matter. skyserver.sdss.org/dr1/en/proj/basic/universe/redshifts.asp www.space.com/25732-redshift-blueshift.html science.nasa.gov/ems/09_visiblelight

@vornamenachname5267

4 жыл бұрын

You are right, but the ultraviolet radiation from even more distant stars gets redshifted even more. Therefore it too becomes infrared. So there is a zone where you can see the 'ultraviolet' light, but farther away, you can't.

@MrLaptopus

4 жыл бұрын

Good question. This video is false and just a misdirection into Big Bang, etc. The reason the sky is dark is because density of light reaching us is low.

this is one of the best explanations i've come across.

this clears up so much..thank u

Haha what a great way of looking at it no pun intended. I never thought of that. Great video.

This is awesome, I never thought that a certain wavelength light emitted from a moving star would actually appear as another wavelength to us I assume that is because of the Lorentz transformation... but if so shouldn't the wavelength actually "become" shorter relatively to us?

@MeronBridgeMR

8 жыл бұрын

(Like becoming UV instead of IR)

@patrickhector

8 жыл бұрын

As space grows, the spaces between everything grows. This includes the space between different adjacent waves in a beam of light, essentially making the wavelength longer. Another thing is that as objects creating any sort of wave moves away from an observer, the individual waves are made farther apart, making the wavelength longer. What you're thinking about is *blue*shift, so named because when an object is moving toward an observer fast enough, any light released appears slightly blue because the individual waves are released closer together.

@MeronBridgeMR

8 жыл бұрын

+Patrick Hector That makes sense. Now I have to explore this topic further :D Thanks!

Good old LEGENDARY early 10s!!!! The best period for someone to be alive! Amazing video my friend!

Had always wondered this. Thanks!

BRAINGASMS!!! I love this stuff, it stimulates my brain somehow. Started to study again with 30 and I would recommend to others too who feel stuck in life or in their job and generally considers learning as a never ending process and enjoys it. Thanks to all the people who do this stuff (Vsauce, RSA, MinutePhysics, FightMediocrity, Brian Johnson, Elliot Hulse and so on) Any Recommendations refering to similar Videos? Education, Psychology, Self Development, ... would be apreciated.

@Huu159

8 жыл бұрын

Try In A Nutshell/Kurzgesagt

@Sinan97082

8 жыл бұрын

Akshay 28392 Warum kurzgesagt?

@Huu159

8 жыл бұрын

+Sinano That was the earlier name of the channel. They explain big concepts in short videos hence "kurzgesagt"

@ash.junaid

8 жыл бұрын

+Sinano Good to hear it man. I'm kinda in a similar situation right now. Check out Numberphile as well. Can't recommend it enough =)

@Sinan97082

8 жыл бұрын

Akshay 28392 Vielen Dank für den Hinweis :)

You forgot one piece of the mosaic - there is actually a "border" beyond which we cannot see. It is where the expansion reaches the speed of light from us. The area of this sphere is said to contain all of the entropy information in our observable universe. There is no classic hard barrier, but the laws of physics make it so that we cannot ever see or get past it.

@shabsi770

9 жыл бұрын

למעלה מגלגל התשיעי, אין שם לא מקום ולא רקות.

Awesome video!!!!!! Best one I have seen yet~ REALLY blew my mind with science :)

very interesting good job henry!!

2:57 Korean Subtitles Typo - "자외선" should be "적외선"

what a complicated answer for a simple question

@BrickBuster2552

8 жыл бұрын

"Y me no see night?" "2 red"

@Titanic-wo6bq

8 жыл бұрын

dat explains it

@EmilioKolomenski

7 жыл бұрын

Start your own science channel, you can call it "SecondPhysics"

@gangstermedia9039

7 жыл бұрын

because it is all bullshit

@raghavnandyal1518

7 жыл бұрын

It's that simple. It's something called the Oliver's paradox, which is still unsolved. It basically says, if there's an infinite number of stars, then why is there light in every direction you look?

One of my favorite videos

Thank you for the great video!

damn I wish I was brainy so I could understand this stuff. If they teached this in school id of listened all I remember doing in physics is connecting a fucking battery circuit to a few little bulbs

@ErojFeeding

9 жыл бұрын

Its not that hard you just have to understand the basics at first :P

@LucaPed94

9 жыл бұрын

Slick Rick Taught*

@ree83ce

9 жыл бұрын

Could be worse + Slick Rick all I do in science is burn stuff ( ussually salt water or something else added to pure water that that dose or dose not dissolve in it ) to learn diffrent things like, why salt dosent evaporate or how to get clean water or somthing wired, I mean, dont get me wrong, you put fire into a lesson, I aint complaining.... unless I get burnt by the fire then ill be a little mad lol

@dee8163

7 жыл бұрын

tell me about it. we keep learning about how light gets reflected or refracted by glass, mirror etc etc

@meryemrashidova5984

6 жыл бұрын

This is what we are learning in Physics just now

I still don't get it.

@lars123mc

10 жыл бұрын

my mouth: intresting my brain: durrrr

@shynnsup8383

10 жыл бұрын

Red Shift. Thats all you need to know.

@MoAli72

10 жыл бұрын

Shynn Sup Now I need to know what 'Red Shift' is... :s

@shynnsup8383

10 жыл бұрын

Mohammed Ali Light changing its wavelength into infrared.

@vottoduder

10 жыл бұрын

Mohammed Ali Red shift is the same concept as when you hear a police car siren traveling away from you except in the form of light waves instead of sound waves.

Awesome video!!!

I believe that Cosmic Microwave Background isn't only beyond the stars but simply everywhere in space/time. Anyhow i think you've done a great video, I love it!!! :)

does this mean if we could perceive infrared light with our human eyes, the sky WOULD be full of light at all times?

@TheThundercool

10 жыл бұрын

It means that, if we were able to see in a wider spectrum of light (e.g. infrared, ultraviolet, or more), we would see many other things that are invisible to our current capacities...

@Evan_Case

9 жыл бұрын

If we could see in Microwaves you would see the CMB (Cosmic Microwave Background) everywhere....

@KasisnuSingh

9 жыл бұрын

Actually you would have to wait a really long time! There would be stars that are far enough that light from them hasn't reached us yet!. The background radiation would be visible as well.. something. A lot depends on how we would actually perceive the radiation. I assume you assumed there was no atmosphere! :)

@nicolasiguaran

9 жыл бұрын

Tethloach Kingofreason Ehmmm. I may think you are wrong. The thing the haets up the earth is not the light, it is the infrared thingies. That we could see them doesn't mean there would be more of it and so the earth's temperature would stay the same. It would be a lot lot brighter, though.

@KasisnuSingh

9 жыл бұрын

Tethloach Kingofreason Not quite. The light spreads out. The further away we are, the less intense it actually is. nicolasiguaran You're close. So both infrared and "light" are the same thing here. *We* can see one and not the other. And thanks, my comment above was partly flawed. Updated! Also, we need the atmosphere for the earth to *stay* warm. Think of other planets or the moon. It can get quite warm during the day but then also quite chilly at night. The reason that happens to a lesser degree on earth is due to the presence of greenhouse gases(in the atmosphere).

Lean back :)

Love you guys!

Amazing!

A good explanation, if a little hurried. The music, though, was a distraction - too loud.

@Pierrot110194

10 жыл бұрын

Well, the channel is called "MinutePhysics"...

@jameslolan829

9 жыл бұрын

Peter Pepper yeah not "HourPhysics" explaining every single fact about one thing!

Stars that are super far away also become etremely dim by the time they reach earth so that our human eyes couldn't see them even if their light was in the visible spectrum. We would still need telescopes to see them anyway.

Wow.....this is awesome.....I appreciate it minutephysics

Omg I love space! It is so cool and it is so fun to know more and more

a question .. if I'm on earth and you are on a planet one light-year away from me, and suddenly your planet explodes, but you're sending me a voice message in the exact time .. what reach to me first? your voice, or the light from the explosion?

@BenjaminStewart6

10 жыл бұрын

It depends on how the voice message is being sent. If it is radio or any other form of communication that uses the electromagnetic spectrum, then my voice being cut off would happen at the exact same time as the explosion, since light and radio waves are both on the electromagnetic spectrum.

@aaronreid5789

10 жыл бұрын

his body would reach u first lol

@mahmouduthman382

10 жыл бұрын

Benjamin Stewart true, but given that the sound was send in the form of a message transmitted using electromagnetic radiation shouldn't it take extra x time to encode & decode the message content back into sound (Voice) ?

I always thought because the dark matter clouds cover a ton of light or bends light lol

@RICE4azns

10 жыл бұрын

It's not called Dark Matter because it's dark. It's called Dark Matter because it is utterly invisible across all spectra of light, only detectable by its gravity. Galaxies are formed at dark matter clumps, so if anything, all the gravity would bend light into galaxies, enabling viewers to see more light.

Very good and quick explanation

thanks alot minute physics. i was looking for the answer since long time.

interadesting

question. can some one be looking back in time at us??

@Poulpink

7 жыл бұрын

yes

@pozpoz2126

7 жыл бұрын

fuck

@RichardPugsley

7 жыл бұрын

So if we had a way to travel really fast to another place far from earth and than look at a certain place on earth, we could see who commited a murder for example...

@carloshgrant

7 жыл бұрын

so to answer you question simply, yes. if you go one light year away from earth and if you could look at it with a telescope, the image you see is 1 year old. it looks like you are watching live events on earth (clouds moving and all) but it all happened one year before. thats just because light has a finite speed and it takes time for it to travel.

@dmmm876

7 жыл бұрын

Yeah, as Carlos Grant said, 'if you go one light year away from earth and if you could look at it with a telescope, the image you see is 1 year old'. The only problem with doing it: it would only really work if we could instantly teleport one lightyear away, or if we could travel faster than the speed of light. Because we'd need to travel a lightyear away from the Earth faster than the light itself can get there. For example, if we have a race and you start a month earlier than I do, I'd need to drive much much faster than you are, otherwise I'd never catch up. The same sorta thing applies here. To see even a month into the past, we'd need to travel impossibly fast to catch up with the light that got sent out a month ago. It's still cool to think about though.

This was beautiful thanks :D

This is one of my favorit videos on youtube. I love it so much.😍

olber's paradox

@MegaBanne

7 жыл бұрын

It is BS.

@01rai01

7 жыл бұрын

***** it is, leads to an understanding of doppler shift, cmb, etc

@MegaBanne

7 жыл бұрын

rai ZOR Not realy olber's paradox is based on asumptions that violates the conservation of energy. Some believe that big bang resolved a physical paradox, but there never was any to begin with.

@01rai01

7 жыл бұрын

***** you misunderstand what I'm getting at

@MegaBanne

7 жыл бұрын

rai ZOR ok

Who else came here from Vsauce?

@ahmedalmatari9758

8 жыл бұрын

Noura Alzarouni I came here from searching up the best science youtube channels.

@69Solo

8 жыл бұрын

+Noura Alzarouni Not exactly! I been spying on you for quite a while. So where ever you go, I go. @_@

@davetylerii8985

6 жыл бұрын

Noura Alzarouni I came here from Vsauce

Excellent explanation

love these.

Oudated. Parts of Universe are expanding, other are retracting. Conclusion: We don't know what the hell is going on out there.

ERROR IN THIS VIDEO? "If we lived in an infinite, unchanging universe, the entire sky would be as bright as the sun." Excuse my english, but my small brain tells me that's not how it goes at all. In my opinion, the most important thing is ratio between bright objects empty (lightless) space. Emptiness wins - big time. I also think that - in this context - this is also the most important thing in real, expanding universe, and red shift effect starts to affect in VERY distant objects. If the red shift were the main reason, we should see dark red(ish), not black background. Feel free to correct.

@jamescarwyncandila8044

9 жыл бұрын

OSOCO Yes? I agree in some part of your opinion. And that it is in the last part of it. We would see some kind of a dark reddish thing. Yeah, we will be able to see some dark reddish thing. But not the whole background of it. Because, As something gets redder, it gets more... well.. dark. And as it reach it's point where literally it's infrared. It would become, black. Because we cannot see it anymore. But if the theory was true, (The theory that I'm talking about is the Infrared thing.) Some animals like boas, will see the night with a lot of red stuff but not totally all. Because some far things are so infrared, that even animals that can see them, won't be able to see them. I hope you get my point.

@osoco7294

9 жыл бұрын

Jemas Dilacan That's pretty much how I think. Anyhow, in my opinion there should be the the whole range of light (because of different red shift levels and distances) from white to invisible infrared added (mixed) TOGETHER, sum total being somewhere between orage and dark red to human eye. That's not the case, so 'emptiness explanation' seems to be WAY more important factor in blackness phenomenon. In that light (no pun intended) there can not be an entity percieving infrared, because of very small percentage of visible objects compared to emptiness in the first place. This is rather hard to explain with my great English skills, lol.

@jamescarwyncandila8044

9 жыл бұрын

OSOCO Nice Englishy things! Anyways, Yeah. You're right. But we don't really know what will be the real factor. But I accept both as a factor. Do you?

@osoco7294

9 жыл бұрын

Jemas Dilacan 'Sum total' is probably wrong term. 'The result of mixed frequencies' may be more correct. "But I accept both as a factor. Do you?" Both factors are real and effective, but I don't agree with this: "If we lived in an infinite, unchanging universe, the entire sky would be as bright as the sun." That's because of 'emptiness wins' circumstance, thus we don't see the effect of red shift factor in the lack of enough light coming to us in the first place, let alone the dimmer light affected by the red shift.

@jamescarwyncandila8044

9 жыл бұрын

OSOCO Exactly

FINALLY,someone who can answer my "out-of-this-world questions"!

This video answered a question I didn't know I had

I thought I knew shit?!

So if we would see infrared, sky would be full of stars all the time?

@coolipopy

8 жыл бұрын

Hrnek Bezucha There are longer wavelengths than infrared

@justinlewtp

8 жыл бұрын

There is a wavelength called far-infared. So the light will be that, as it is moving away

@MartinBrada

8 жыл бұрын

And the cosmic microwave backgroud, as you can see from the name, is microwave.

@MrWestSky

6 жыл бұрын

The atmosphere won't let infrared light past through into the Earth, that's the point of it. Hubble can take pics of it because it's in outter space. So if we were sensitive to infrared, we'd still see the night sky dark.

Thank you, the video is awesome

I thought the reason the sky was dark at because we were so far away from other stars

Does dark matter have to do with why the Cosmos is so dark?

@breakthewastedspace

8 жыл бұрын

Dark matter is invisible

@rizzley980

8 жыл бұрын

But how can you explain blackhole? Dark matter + particles + vortex .. You can see neither and light can't get pass through it because it is so dark

@AlchemistOfNirnroot

8 жыл бұрын

+Trainer_Poke Doesn't interact via the electromagnetic force*

Thanks for this informative video. I will surely share this to my school friends.

This actually helped me understanding the 'Cosmic background radiation' thank you Henry !

it is dark at night because batman wants it. He is the dark knight.

@toastedclubsandwich

7 жыл бұрын

Thank you, Homo Erectus.

I DON'T UNDERSTAND! THIS MAKES ME ANGRY!

@michychu3873

5 жыл бұрын

Alec Beach ikr

I use these videos to freshen up my knowledge and to see if I still remember these things

I can listen to your voice all day... You have great information in your videos, and since I have synethesia, your voice smells like the beach. And I love the beach.

Thanks. Now I won't be able to sleep at night.

i dont understand :( !!!!

@quinnbaugh2398

10 жыл бұрын

As we know space is expanding, the stars are moving away. And the farther they are from us the faster the stars travel. As it goes on and on it becomes redder and redder until we can't see it anymore (at least with a naked eye). That's why it's dark at night, Aman Dahiya. :) : D

@metalvinnyofficial

10 жыл бұрын

Humans can't see infrared light.

@amandahiya94

10 жыл бұрын

Cool Math huh?

@flaminggaming4621

10 жыл бұрын

Aman Dahiya Space is always expanding, and the stars are moving with it, and as space gets bigger, and the stars get further away, they become red. As all this happens, space gets bigger, causing the stars to get farther away, making them get redder, they go infrared, which the human eye cannot see.

@WJames-nq2df

6 жыл бұрын

Also factoring in the time between when you see a star and when a star is either created or when it dies. The blank spots may be home to stars that produce light which will never reach the human eye due to the long distance. And the stars that are there may have died long before humans came around but because they're so far away and the speed of light is so limited, the light those stars shone will be seen long after humans no longer exist.

MAN! where do you get this sort of information? You truly deserve a nobel.

Who ever did the work with the marker is very talented and I enjoyed this video largely due to it. Well done.

@smorgastartan7913

10 жыл бұрын

the guy with the marker is the guy talking aka henry

It's not that the dark is at night, it's that when the dark came, people called it night.

NO EDGE!

@PedroHenriqueScloneski

10 жыл бұрын

DUDE, NO EDGE!

you are the best teacher evey i have,, i like the way you explaine and drawing,, plz littel slow down so we undrestand better.. thanks again for everything

great summary for Olbers' paradox

brain fart. i have to write a two page paper on this. you covered it in 3 mins. and im still slightly confused LOL

@MrHorimiya

9 жыл бұрын

Geez you're asian, you should understand !

@birk7348

9 жыл бұрын

Only 2 pages!?

@CrazyDoug17

9 жыл бұрын

***** What is an ''Azians'' ?

I'm pretty sure dust has a lot to do with it, too.

@albionxhediku9788

5 жыл бұрын

no

henryy!!! you are awesome!!!!!!!

Please make videos on why exactly the red shift is caused , and thanks for this video by the way!

Wait. If the universe is infinite in the space it occupies then how can it expand?

@freedfighter96

10 жыл бұрын

It's not infinite

@Alexandra-ip2by

6 жыл бұрын

Dun dun dunnnnnnn

@seanspacey4452

6 жыл бұрын

The idea is that if the universe is infinite, spacetime expands into itself. It's not that easy to visualize and I couldn't find a nice gif but here is a good video that helps: kzread.info/dash/bejne/nYpnldZxhZndYps.html But the same question can be asked for a universe with curvature. If the universe is not infinite, it would still have to expand into itself because there is no such thing as "outside" of the universe because outside refers to a position and position only exists within our universe because there is spatial dimensions.

There's a simpler reason: The stars are too far away and not bright enough. Virtually all stars the naked eyes can see are in our own galaxy. Even the Andromeda galaxy, which is really close and consists of numerous stars, is barely visible. So the fact that star's aren't visible from the universe outside our own galaxy with the naked eye has barely anything to do with the reasons given.

@chakaval100

9 жыл бұрын

Agreed. I think it is like trying to see a candle light miles / kilometers away.

@Oinikis

9 жыл бұрын

That's not true. For exmaple, if we double the distance between us and a star, we will receive 4 times less light, however, it will take up 4 times less area of our vision, so since they both change at the same rate, when an object is moved away from us it only gets smaller in out field of view, but the brightness density stays the same. For example: if you place a computer screen far enough, you won't be able to see individual pixels, but you could still see the screen. and if you move it so far away you can't see the screen, you can stack screens on top of each other and to the side, and still see them, and if you leave no gaps, it will still have same brightness. This is both beautiful, and scary.

@john42t

9 жыл бұрын

Oinikis If you leave no gaps, yes. Space, though, is mostly empty, and even the gap-to-no-gap ratio is "almost all gap".

@Oinikis

9 жыл бұрын

But if space is infinite and eternal, then there would be no gaps. This prooves universe had a beggining

@john42t

9 жыл бұрын

Oinikis It's an interesting argument. Disregarding speed of light and assuming an average star density, an infinite universe should look infinitely bright. I'm pretty confident that the following holds for our universe though: Earth is part of a larger galaxy. If you'd look outside the window of a spaceship at a suitable point far away from any galaxy inside the local group, you'd possibly see two faint dots in the entire sky and nothing else (Milky Way and Andromeda). If you'd move far away from the local group into intergalatic space, you'd see nothing at all. Complete and total blackness. And that even holds if you remain in an area of the universe with a high density in galaxies. Most of the space is located in great voids that are particularly empty. So if you move away from our galaxy you usually get into space ever and ever more devoid of stars by orders of magnitude. However, that doesn't really refute your argument. Since if, regardless of how far you go, the density of stars remains constant over sufficiently large areas of space (we're thinking truly vast areas of space though), it should still be true that the average perceived brightness should even be infinite (if I think correctly here). There is, however, also the speed of light taken into account. The farer you look the more you look into the past. Indeed you can see "light" from all directions in the form of background radiation as talked about in the video. So the distance you can see is in fact limited by the age of the universe times the speed of light.

In my opinion this is the best video so far

IN ENGLISH PLEASE? -MINUTEPHYSICS

its because the Dark travels faster than Light

@gangstermedia9039

7 жыл бұрын

lol

ohhhhhhhhh that clears things up thank you. I was wondering what the answer was, thank you, you have earned a subscriber.

Beautiful!

Fuck, I didn't know why I wanted to kill myself, until I realized I was in the nerdy part of KZread.

@TheFishCostume

10 жыл бұрын

I don't understand that, but okay.

@bigballsgame5591

10 жыл бұрын

You can call "science" the theoretical development of techniques meant to improve your sex life. Asking whether the sky is dark or not when, for all intensive purposes, it is and forever will be pitch fucking dark, is not just nerdy, but virgin fucking lame. I can't believe how you try to pull me into your fucking lame sad world.

@l3orn2Film

10 жыл бұрын

bigballsgame Nobody tries to pull you into anything, you came here you fuck face. Fuck off

@Chordseeker

10 жыл бұрын

bigballsgame rofl, you made my day. :D Not sure if joking or trolling, but you are surely free to go spend your quality time improving you sex life then learning something, unless it is less "science" and more "science-fiction" for you. :)

@Jaspertt1

10 жыл бұрын

Go to your cave... You won't get much more if you don't appreciate this stuff ;)

Well, why isn't the sky red then?

@marieflynn9420

9 жыл бұрын

Luke Riley Because it's infrared which is impossible to see with the naked eye.

@coolipopy

8 жыл бұрын

Luke Riley Eh. Rayleigh scattering

@janablahova8116

8 жыл бұрын

Luke Riley Ha, ha... good qestion

@dependent-wafer-177

8 жыл бұрын

+Luke Riley Dude really?

@dependent-wafer-177

8 жыл бұрын

+Jana Blahová Erm no not a good question, INFRARED doesn't mean you can see it, infrared is invisible to our eyes like the guy kept on saying in the video jeez

Wow after watching so many of these videos I think that I finally understand!! I'm getting so smart 😁

Good one!

I don't like his accent. He keeps using that irritating tone~ towards the end of most sentences...

@crobatron6802

10 жыл бұрын

you little mean person

@musicboxer1

10 жыл бұрын

I don't like you :)

Omg, I never thought about it before despite being a physicist. Indeed, it's a super curious problem to think about.