Why is the Night Sky Dark? | Neil deGrasse Tyson Explains...
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- Опубликовано: 22 май 2024
- Why is the sky dark at night? On this explainer, Neil deGrasse Tyson and Chuck Nice go over Olbers’ Paradox and why the night’s sky is dark. Hint: it’s not just because it’s nighttime.
Why isn’t the entire night’s sky ablaze with stars? We travel back to the early 1800s to discover Heinrich Wilhelm Olbers’ confounding question: if the universe is infinite, shouldn’t every sightline land on a star? We discuss physics and equations for star brightness. If you put the sun three times farther away how much area in the sky does it take up? How did discovering the expanding universe finally help confirm this question?
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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!
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0:00 - Introduction
0:52 - Surface Brightness
4:12 - Olber’s Paradox
6:16 - Hubble’s Discovery
7:40 - How Light Travels
10:38 - Closing Notes 
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I love how well Chuck brings it down to my level.
Stop feeding his ego
Neil brings it down to a lower level, then Chuck brings it down lower.
I realize that this sounds like a negative thing, but it's a good thing.
If only he would stop yelling.
lol I feel like you commented this after his uber comment
@@dom_blvcc lol, very astute 👍
I love it when they edit in a visual of what they are talking about because I have a hard time visualizing in my head what they talk about. Thank you for that!
Thanks for the feedback!
@@StarTalk You're welcome!
I love that Neil has a sense of humor. With great intelligence often people lose it and are condescending. He amazes me every episode.
He has got a great sense of humour but his jokes are a bit corny, which kind of makes them funny. I love his passion.
If you have time , check out a lady named Maggie Aderin Pocock.
She is a British lady who appears on TV over here in the UK. She is absolutely bonkers about the moon. Reminds me of Neil a bit. 🇬🇧👍.
I am unconvinced about him. He says he’s a physicist but he sounds like a philosopher.
He is actually condescending. Watch his Joe Rogan interview. It was hilarious how condescending he was to him
@Mario Luigi well I don't mind him being condescending when it's towards someone who consistently acts superior, and like they're the smartest person in the room when they're, obviously, not.
@@jimr9499 How does Joe Rogan act superior? In fact, that's how Tyson acts
Fascinating explanation! It’s always astonishing how we take things like this for granted, and that most of us don’t know such an amazing thing happens every night!
Science is everywhere and it’s amazing!
Alex, it happens all the time, not only at night...
It’s always night in more or less half the earth so it happens continuously.
@@SjaakSchulteis it’s always night somewhere. Good attempt to sound smart though! 👍🏻
@@StarTalk But isn't simply how optics work enough for the sky to appear dark to us?
Obviously the sky isn't dark to a telescope... Hubble did saw all those other galaxies, so this has more to do with light pollution than anything else...
Even an infinite non expanding universe with an infinite speed of light (which it kinda is, light speed is effectively infinite, or in scientific notation, the proper velocity of light is infinite)
it still wouldn't be enough for the sky to be blazing with light...
In the day because of the Sun, cuz it blocks all the other light due to how bright itself is...
And at night again, even far away from the big city lights, the bright stars are sufficiently bright to obscure to us, the light of the other infinite stars...
Our Galaxy has enough stars around us, to overcome and be enough for both the expansion and the speed of light limit, to fill the sky with light. Our Galaxy alone can do this...
And still we don't see all those stars. Not because they aren't there, but because our eyes can't see them.
And that's why we have developed better eyes, called TELESCOPES, that let us see all this effectively infinite light, that's coming to us.
I think that Niel missed a key point in this, no?
The chemistry between these two guys is so fun to watch. They could be talking about anything it would still be interesting and funny.
It's not chemistry, it's _astronomy!_ 😆🤣
Thank you! I love these videos… please, don’t ever stop doing these 🙏🏻
Okay! Since you you asked.
After our sun expands and explodes in about 4 billion years, then these videos might stop comming out ;p
Agreed
I got to tell you, I came to this video with little expectation, but it blew me away. Great material
Thank goodness for Chuck. Throughout my academic career, I was always a "history/English" nerd. I never did too poorly in any subject, and perhaps it was the teachers and their particular style of teaching, but science/math was simply never my forte. And, so, I am thankful for Chuck. Neil explains all the mathematical intricacies of a topic, and I kinda sorta get the general gist of what he's saying. But then Chuck comes along and reiterates it in a way that even a simpleton like me can understand.
Thank you both for the service you provide us! StarTalk, truly, deserves to be classified as a public service and, as such, receive public funding. This show brings such interesting, useful, and fun information to us, and I really am so thankful.
I've always loved how science makes huge discoveries from the most simple questions.
why does the apple fall down?
why is the night sky dark?
why is water wet?
and the answers are constantly mind expanding.
my personal question is why do we assume the universe expands as a single unit.
my hypothesis is that discreet areas of space, energy fields, are expanding into each other.
this concept allows for a unification of the fundamental forces and doesn't require a "big bang".
spaceandmotion
Water isn't wet though
@@dreddscott3873 True, but someone asked that question which eventually led to the realization of what what "wet" means.
People need to be allowed to ask any question they can imagine in hopes of it leading them to a greater understanding of the world around them from a scientific point of view.
If a person asks you about water's wetness, don't just tell them they are wrong. You need to explain the reason.
@@dreddscott3873 Fish, as a whole, would like a word.
@@meridien52681 water isn't wet. Fish have nothing to do with it. Wtf are you on about?
These videos are fantastic extensions of the Star Talk content universe. Keep up the great work!
OMG LOL Chuck is on it out the gate. This is going to be another great episode.
You two have the best chemistry! Teaching, learning & laughing! It’s fantastic! Love you both!
I think I missed something about the inverse-squared law. The way he described it sounded like it would be 1/9 * 1/9 = 1/81, not canceling out. Imma hafta figure out what I missed
Same here
Totally agree
Just take a simple flashlight and take it a long way away it's not as bright as when you're up close
@@dscollo but he said it IS the same brightness regardless of distance. Which seems both counter intuitive as well as the opposite of how he described it
@@dscollo It’s the same brightness but to us it appears dimmer.
When I read the video title I thought it was obvious but then I remembered that Neil always makes things interesting.
I just can’t explain how much I love Neil and his brain. It’s so absolutely beautiful, I think I could have hours of conversation.
I love that you had an infograph to help explain what you were saying. There have been so many other explainers where I wished everyone could see what you were saying. Keep up the great videos!
I have to watch all of these SmartTalk videos 3-4 times so I can understand and remember all the info they give. I am very thankful for these videos.
We’re glad to hear you’re getting a lot out of them :)
I just keep watching until I get it ...it takes as long as it takes.
I don't know why but I literally clapped at the end of the explanation. Like always an awesome video, NDT explanation is just beautiful.
So nice having those brilliant explanations of phenomena, I love it. As for the "not knowing something", Cicero, I think, said something along the lines of "I am not ashamed to admit I don't know the things I don't know." For this is one of the chief the marvels of humanity, this intrinsic curiosity that drives us to uncover when we don't know. I might as well stop here cause I'll make ignorance our greatest boon if I go on and I don't want to go there.
Those answers to simple questions are just fascinating. Really make you realise what is really going on around us.
Great content.
No matter what kind of mood I am in. Y’all bring the humor and brighten things.
I literally just commented the exact same sentiment on another video of theirs! So true.
Wooow, love the new graphics during the explanation
This is way cool. I love astronomy and there's so much to learn, this was fun to learn and an easy to understand explanation. Thank you!
Love Chuck and Neil together! Love the Explainers! I can't see the night sky from where I live...so any interesting fact astonished me!
😮 Where do you live?
@@StarTalk Maybe he lives in a House somewhere at the surface of the Sun ? :D
@@StarTalk I mean, there's that place in Norway where they get like 4 and a half months of straight daylight. But even they get nights eventually haha
i remember listening to my astrophysics teacher talk about this a gew weeks ago and ive been fascinated by it and all the stuff that goes into it.
Love the use of visuals
This is so cool. I love how you guys explain this in a fun way. Keep it up! 💯 ❤
Very intriguing again, thank you Startalk
In an expanding universe, have we ever observed a galaxy going dark as it moves beyond visible range? E.g., a very dim and red-shifted galaxy appearing on early deep field photos that does not appear on recent ones.
Oooo. That is a very interesting question
No.
For a simple reason: the expansion is small.the redshift takes millions of lightyears to become relevant.
And with increasing distance, and increasing speed, the light frequency goes lower and lower, and from visible light to infrared and below.
And to catch the moment where something that is just detectable to the point that it is not detectable anymore (because our sensors cannot register such low freguencies anymore) would be sheer luck.
And not being detectable is by far not having gone beyond lightspeed (so fast that the light will not reach us anymore).
Next issue: The lower the frequency, the worse the resolution. Simple physics: the shorter the wavelength, the better the resolution. Like in radio: to increase the datarate, the smartphones have to use higher and higher frequenceis = shorter wavelenghts. Early radio used super-low frequencies, just a few hundred to a few kilohertz. Therefore more than morsecode (a few bit/sec) was not possible.
And finally, in order to "see" something so far away, you need VERY long times of observation to collect enough photons to give an image. I think the Hubble Deep Field took 4 weeks to complete. And the area that you can cover in that time is extremely small.
So going far out, so far to make the observation you would like to see, takes ever more time and covers ever less area, which decreases the probability to catch the right spot at exactly the right time.
Wow, think about the implications. Because we would never, ever see it again it would be dead to us, extinct, a relic of our past history! It really is quite profound. Imagine if we could have plotted the sky in the early civilisations ie Chinese/ African and compare it to today! Good question!
What if these galaxies are still sending light but by the time it reaches us, it is so far red-shifted, we perceive it only as cosmic background radiation? What if COBE isn't observing 'remnants of the Big Bang' but rather the residual light from these receded galaxies?
@@adam23skyline There is a point in the future of our galaxy wherein the expansion of space has rendered everything outside the Milky Way invisible to us. Like 100 trillion years from now or something like that. Blows my mind
"It's smaller" 🤣 thank you Chuck
Neil could not possibly find a better co-host/chit-chat buddy than Chuck! I love these guys!
The Olbers paradox is my favorite piece of logic that somehow proves something profound about the Universe simply by reasoning about it
Great video!! I have two questions:
- What about interstellar dust? Wouldn't it difuse the light?
- And what if the Doppler effect would shift light below our visible threshold?
The dust can also block the visible light, that’s why we have to use infrared to see Sagittarius A*. The Doppler effect also plays in, but that, imo, the expansion of the universe, infinite or not, is the biggest reason why we see a dark sky. Most of the light will never reach us.
I came here to say the same thing. Dust is such an easy explanation. I can't believe it was ever a "paradox".
I read somewhere else that the amount of dust required to account for the dark at night would be ridiculously high, so that it should have collapsed or it would be also heating and radiating.
@@duncanfeyd4056 Paradoxes over time tend to be "resolved"... They're not always solved, which renders them resolved as they're no longer a paradox... BUT upon finding and deciphering further information and understanding it in principle, "solution" is one of the directions a paradox will go. Others, upon further information and understanding, become apparent non-sense... and are no longer paradoxes, but kind of like jokes about how "primitive" our society was in a certain era.
But they tend to get "resolved" as we (humans) gain the intellect, technology, and wisdom to figure them out. They're STILL important as sort of "Intellectual way-points" showing our collective progress from when it seemed like a paradox, because we simply didn't understand enough, to when we figured out the resolution, either disqualifying the basis factors as "actually unrelated" or finding a "real solution".
Before Hubble's discoveries (among others), the question was a legitimate paradox, based on as much as we understood of space and the universe at the time.
AND it was a well regarded paradox, because as scientists, whenever you encounter a paradox, it generally MEANS you've missed something somewhere. It's just the proposal of the "riddle" such as it is, SHOULD be solvable with the information at hand, if we really "had a good bead on everything"...
SO another useful function of paradoxes is that they continue to signal and mean that the world's scientists are STILL humble enough to have to admit, "We don't know about everything." ;o)
Dust would heat up and re-radiate the light
I always love both of you explaining things how you do. I learned a lot here today. Thank you ❤️
Glad to hear you learned something!
Greetings from Ghana! I just love you two!!
Love this guy, his sidekick, channel. So true. So logically explained. Every student should attend these lectures while still in high school.
Does random matter/dust block light too? I would imagine it’s a significant portion considering even interstellar space isn’t completely empty.
I was thinking black holes would be creating some blind spots, but now when I gave it a thought, In a infinite universe, if you are outside of event horizon you can't be in a blind spot.
I was thinking exactly the same thing. You wouldn't even need the expanding universe theory and the speed of light limitation to explain the paradox in that case, since most sight lines would be blocked by particulate matter. I know, i'm probably failing to understand this completely, so I hope you get an intuitive explanation for your comment from someone who knows better.
@@Pi5hvi the problem with that logic is that if those planets and debris are absorbing the light over billions and years and not emitting any of it, they would be heating up and so radiated, that they would eventually begin to transmit light
@@omarmohamed1215 That makes sense. Thank you Omar, I totally failed to consider that!!
I once (or even multiple times) looked at that very highresolution picture of the Andromeda Galaxy, where you can zoom in and see that every little spec of light is a star, amazing photograph, the reason I mention this is because it got me thinking and it comes close to Olbers Paradox, The andromeda galaxy looks a bit like ours and we are in an outer arm where darkness is possible because of what you explained, but if you zoom in to the center the amount of stars is staggering more stars are clumped up there being closer to the central Black hole I guess, And I thought, what would it be like over there? If there where a planet where life was possible (just a thought maybe it is possible maybe not), let's say like earth, and your own sun sets but there is like thousands of stars in close proximity to you, where Olbers Paradox would not be a paradox, they would be so close that light rached you and it would be in your own galaxy, even in your own stellar neighbourhood, could it be that in those places Olber would be right? Could you just not sleep on that planet because you can not escape light anywhere? Except underground maybe?
Interesting. Life forms there would probably evolve to sleep when it is light out.
Just to say thank you for these. I have major interview anxiety today and music didn't help, meditation didn't help, but these help a ton because they are very interesting
Love both these and your Snapchat videos. Your editor on Snap is great!
The entire sky is glowing with very little variation. It’s just red shifted into the microwave. 😅
Didn't expect to see you here, Cody!
Cody simpson here
Damn!
Yeah thats's true, CMBR. Well spotted.
Wow! ❤
CHICKEN HOLE BASE FOR LIFE!!!
Love the content guys, please keep it going ❤
This is exactly why I listen to you guys! I've got a new perspective to carry with me.
I actually leaned about Olber’s Paradox from a delightful novel by Diane Duane called High Wizardry! In the climactic finale, the main character defeats the Dark One (The Lone Power in the novels) with the power of light. (Darkness comprehendeth it not). To do this, she stopped (temporarily) the expansion of the Universe! Great stuff!
The first obvious solution to this is that as stars are further away, they become dimmer and then at a certain distance we just don’t see them. I don’t understand Neil’s explanation of saying if the sun was further away we would see just as much light. How is that possible? It obviously becomes dimmer as it gets further away. I’ve watched other explanations of this paradox and the reason why you would still see light from more distant stars is different to what Neil says here. Essentially at a further distance, there is a larger volume of space and so more stars and their accumulation of light would be equal to fewer stars at a closer distance. So is his explanation correct?
Well going based off of what Neil said and assuming nothing's in the way and distance wasn't changing, if a star is super far away, even if brightness is the same, it would be extremely small. So it's not that it got dimmer but very tiny. Imagine a bright white monitor. Then imagine the same monitor but just 1 pixel is on. It would be like that. So the paradox is that if we assume the universe is infinite, there should be a star at every tiny point in the sky thus the sky being all bright.
Watch again
mrjaffa1013 it seems like he's left something out of his explanation as to why you'd divide 1/9 by 1/9 to get 1 to show intensity of the sun never changing, despite distance.
Edit: He's using the apparent size of the sun in this example as 1/9 as large in the sky when it's 3x farther away, but stating it's STILL generating 1/9 of the intensity (via the inverse square law), creating an intensity of 1 (or 1/9 divided by 1/9) when you observe the sun in a straight line to its surface. Took a few other places to reference what he was stating, but I believe that's the point.
@@Beefcake_HD Any number divided by itself is 1. Doesnt matter if it's a fraction or not.
Only half way through an astrophysics degree myself, but I'll double check on that.
@@jasondean88888 the question is why is he dividing to state that the sun would be just as intense 3x away as it would normally? Good job on your asstrophysics degree tho! I'll bet that's expensive
I've heard all this before. I wish you would talk about something a little more abstruse and don't be afraid to whip out the mathematics behind the abstruse concepts. Thanks.
You guys have single handedly gotten me curious about science
I was taught the paradox in university, but sadly not in astrophysics, so I never learned the solution: now I have it! Thanks, Neil!
Imagine how intense the night sky would look if light speed were infinite. I suspect we'd see areas of solid white light due to the number of stars that we currently can not detect visually.
imagine if the universe just suddenly stops expanding, we would know as we get blind
@@Sacrengard
That would be scary beyond words I suspect. Not every object would stop in their trajectory when expansion stopped, which I imagine would cause some impacts in places.
Add in the sudden increase of visibility.... damn! lol
@@theduder2617 Yeah the universe has to be a simulation and the fact lightspeed is now infinite out of nowhere proves it
@@evo2542
Two incorrect statements you made.
The universe is in no imaginable way a "simulation", and light speed is in no imaginable way infinite.
Speed of light has been mathematically agreed upon based upon observation.
All sorts of scientific calculations would break down and become unusable if light's travel speed were infinite.
If light speed were infinite, there would be zero delay in communication from one side of the planet to the other.
Communications with rovers on Mars would be instantaneous instead of the delay which currently exists.
The "simulation hypothesis" is unsupported nonsense and only exists within mathematical calculations, but ONLY if specific data is entered. Specific data not supported by observation and measurement might I add.
Theories have supporting evidence. Hypothesis are merely thoughts and opinions which do not have supporting evidence. Hence why it is called "simulation hypothesis".
@@aman-qj5sx
Absolutely correct. Our energy efficiency within electronic devices would increase exponentially for one.
But we would have to develop MUCH BETTER semiconductors first.
That is actually interesting to think of all of the differences that would exist.
Thank you for expanding the thought exercise!
Love it... is there any TALK about what is Gravity? That eternal quest of TerraPlanists.
Flat earthers will forever refuse to consider the concept that on a globe the verticals (the direction of gravity towards the center of mass) is diverging, but that this diverging is so little that in everyday life it is completely irrelevant.
@@feedingravens It's always the same subject, they always answer that physics can't explain gravity.
@@FaroiaAlves Even if we cannot explain it, we can DESCRIBE it, with formulas that deliver correct and verifiable results.
Flatlings cannot explain ANYthing, especially not their own oh so simple flat earth. They are totally disinterested in flat earth. They only want to disprove the globe, be RIGHT and all the other people that think they know so much more shall be deluded, indoctrinated idiots.
Thank you for what you do. Bringing knowledge to people like this is a priceless gift. Can’t say enough how much I appreciate you
On our workshop for astronomy olympiad finalists here in Nepal, the first thing our professor who gave the talk said about was this. Glad to see yt recommending me this.
Olbers' paradox stems from the idea that sight lines should be everywhere in our universe, given that the universe is indeed infinite - as the physicists were unknowing of the infinite nature of the universe during the 1920s. The fact sight lines should be everywhere reasonably means there should be no spot on the surface of an object in the cosmos which isn't illuminated by light from all the bodies of the cosmos. The mathematical reality Olbers founded was the inverse ratio of light. The distance of the light source divided by its apparent size equals its constant brightness from any point, be it far away or closer up. The night sky of an infinite universe shouldn't be dark following this as the brightness from all the stars should strike and illuminate every point of the Earth's surface. This lead Olbers to conclude the universe is finite, seeing as there was a limited illumination of the surface of the earth as well as other bodies. The explanation to this paradox is now agreed that the universe is expanding therefore the the light from the ever-present stars is elongated to a wavelength which isn't visible, I think this may relate to the comic microwave background but I'm not sure yet. The other agreed explanation is that light is, of course, finite in speed. This means most of the sight lines haven't crossed the line yet, the light simply hasn't reached us. Like an uber you know is on its way but hasn't arrived to pick you up yet.
Thank you for this explanation.
The U(Ol)ber example was hilarious
@@berl411 Thanks!!
@@IntheClutch75 You're welcome!
I had an thought that it could be interesting if a star system were more isolated from it's neighboring stars so that the lack of night illumination could encourage evolution on a exo-planet toward something like bioluminescence or discovering electricity sooner. If that were the case then their progressive rate for electronics could advance quicker.
bioluminescence maybe, but development of artificial lighting with implies intelligence, and it's not clear how having a darker night sky would be a selection pressure for developing intelligence that would be capable of scientific discovery.
More likely creatures would be pushed towards echolocation, infrared vision, or smell
Evolution does not move 'toward' anything. You're thinking in teleological terms, which is erroneous.
@@Grim_Beard evolution is moved towards different adaptations. The selection pressures determine the outcomes. Saying evolution is moved towards something is equivalent to saying 'changes in a population ' are moved towards something. Perfectly valid
@@hareecionelson5875 No, evolution does _not_ move toward anything. There is no goal.
@@Grim_Beard moving towards something is not the same as a goal.
Also, in some sense there is a goal: move towards the optimal body plan for reproduction in this environment.
This is why animals have developed similar body plans to prehistoric animals that they are not homologous to (the features arise independently)
Lord Chuck have done it again.
The Neil-Chuck combo is amazing - entertaining and enlightening.
Thank you, all of StarTalk crew!
This is such a fun show to watch. These guys always bring a smile to my face.
LOVE YOU DR. TYSON AND CHUCK! YOU GUYS ARE THE BEST!
Because universe is expanding faster than light's speed towards us from stars.
Another example of how science is counterintuitive and you have to take so many factors into account. Awesome!
Thank you for this explainer. This is one of your most fascinating videos.
Thank you for the kind feedback!
Love these videos. Keep up the good work!
I'm glad he brought this up.
I came to this realization myself without learning the history of this paradox.
I knew I couldn't be alone in this way of thought.
The universe is filled with light and not dark. The dark sky is simply the areas where the light is either too dim or to far to reach your eyes.
Great opener!
I
Must
Review
The
Paper's
Star Talk is the best thing that happened to youtube. :)
I loved this. Really helped me grasp the understanding of why all these stars light will never reach us. Really a mindgasm thought. Cheers
Olber's Paradox is a nice observation. Great video.
Mind blown twice in one video! Love this format. GET IN!
I listen to you guys at night before bed every night, Chuck's sudden screaming freaks me out every time. Chill man 😆!
As a gardener I coined a term called SASS- surface area sunshine for plants,
and that is basically what NDT is saying, but with the added factor of how much time the direct light is on the plant.
I love your video
The way you explain cosmology that an average person can understand is awesome and fascinating.
I love this stuff!!! Tell me more, please?!
“We saw it go down bro” the relatability of humor and intelligence is refreshing.
The best RUclips channel yet (according to my personal rating system).
I have always wondered this!!!!!! Thank you Dr. Tyson!!! (… and for the Hayden Planetarium voice, 😍😍)
I LOVE YOU TWO! I LOVE STARTALK! PLEASE NEIL KEEP DOING THIS FOREVER! 💙💙
I freaking love you guys!! So much knowledge and humor. 🤜💥🤛
I feel like after all this time, Chuck should at least have an honorary bachelors in something from being on all these explainer videos. I love these so much.
This is a great story and so well told.
Forgot about this one. Very cool
I love the mix of science and humor!
You guys are real life Tim and Moby😂 makes science interesting, really grateful to have you guys
I've wondered about this before. I was left going "oooooohhh I get it" after watching this video. Thanks for the knowledge!
This was so freaking good.
Going to see Dr Tyson Sunday in Huntsville. I can't wait!!
Chuck Nice, answering the deep scientific questions of the day. 😄😄😄
Thanks, StarTalk and Neil, for giving me a bit of sunshine in my dark world. 🖖🏼❤️❤️🙂👍🏼
Thank you for these podcasts. I took Intro to Physics in HS in the 70's but pursued a diff career path. But I am firm in my belief that learning does not end at HS or even a college degree. I believe we have a problem in this country with people thinking once they get a diploma, they are done learning. I believe this is why we have social scientists who are unable to solve the homeless problem. I believe this is why we have people stuck in dead-end career paths (or laid off and replaced by imported workers) because tech has advanced but they haven't. I learn a little more each time I listen this this and other podcasts on a wide variety of topics and disciplines. This has to be why ppl regard me as the 411 for info--if they would stay current instead of binge watching Netflix shows or finding the next restaurant, they would be informed. Learning doesn't end with a diploma.................
The fact that you believe that we need some kind of "scientists" to solve the homeless problem is just ridiculous.
You don't need scientists. You need politicians with the desire to solve it and the will to see it through, while ignoring the screaming lunatics and bleeding hearts who would rather do nothing about it, because...well...you know...god forbid that you actually upset a bunch of drunks and junkies.
Many countries in the world have zero homelessness. They didn't need scientists to achieve it, either. Their populations have simply decided that they don't want their public streets to look like toilets.
really relaxing
This is one of the most beautiful things I have ever learnt!
Love you guys so much fun
Just a few days ago I was wondering to myself why the light from all of the stars all around us don't make a blaze.. and today I stumbled upon this video. Damn.. the Universe working towards making a person learn more about itself.
I just love how my personal astrophysicist just cracks up! What an infectious laugh!
The Chuck BASSDROP coming in QUICK AS LIGHTNING on this one whooo !
Don't stop making these vids !!!
I loved this video and did my own research into it! I think they way Neil explained it, although wasn’t wrong, just didn’t make sense that no matter the distance, the surface brightness remains the same. I think the example of the sun was too narrow. From what I understood, as the distance you look out to the sky expands, so does the number of stars and galaxies and the intensity of light of all those stars is proportional to the distance because there are more stars to compensate. Just for anybody that was alittle confused as I am!
It is AMAZING the things we learn and the understanding we acquire with the aid of modern technology and hash brownies!
I’m so happy I drew a little drawing to help me explain it, I even got the answer a little bit before Neil said it 👏🏾‼️
That was good!!
Am listening 🎧...am willing to learn
I love Neil deGrasse's Tyson's explanations.....here and other videos. It makes people like me that don't know physics enjoy physics.
Great subject