Hubble image of galaxies | Scale of the universe | Cosmology & Astronomy | Khan Academy

Hubble Image of Galaxies. Created by Sal Khan.

Cosmology & Astronomy on Khan Academy: The Earth is huge, but it is tiny compared to the Sun (which is super huge). But the Sun is tiny compared to the solar system which is tiny compared to the distance to the next star. Oh, did we mention that there are over 100 billion stars in our galaxy (which is about 100,000 light years in diameter) which is one of hundreds of billions of galaxies in just the observable universe (which might be infinite for all we know). Don't feel small. We find it liberating. Your everyday human stresses are nothing compared to this enormity that we are a part of. Enjoy the fact that we get to be part of this vastness!

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[sindicite]

these videos deserve so much more credit and light in a general public sense being that people who constantly wonder about life outside of earth would be able to grasp what that truly means given the astronomical scales of the observable universe. learning that the observed 13.2 billion ly stuff is now 45 billion ly away is enough to show a scale of how hard it would be for some being "nearby" to "visit"

[jpsluckhaus]

I was on the khan academy website and wanted to go to youtube to just so I could click like on this video-this is amazing. 

[spackjarrowdohnneyjepp]

I have always watched shows that talks about the universe such as (How the Universe Works) I've been watching shows like that for about one and a half years and I love how God took all of his time to create this universe.

[MikeTrainormusic]

Sal, thank you so much for your hard work man. You're an excellent lecturer, congrats on your ongoing and continual success

[Rawrishable]

Thank you so much for making these videos! You help me so much through college! PLEASE dont ever stop!

[Aaron_Gentry]

I just cannot wrap my mind around how unimaginably far away these galaxies are, how many stars and planets they could possibly hold, or how incredibly old they are. And that's not to speak of the countless oppurtunities for life to have arisen

[amruthagujjar]

What's more amazing than the universe itself, is the fact that humans have reached the ability to even detect and learn so much about it.

[hoarybat]

OK these are hubble.  Imagine what the JWST going up and out in 2017-2018 being able to see with a 50+ FACTOR over hubble will reveal and being infrared seeing through Nebula will reveal?  Yup it will show we have underestimated the amount of Galaxies in the Universe again!

[econguy]

Hahah "That's a nice looking galaxy right there"

It sure is Sal!

[atheistexchristian]

in all those galaxies imagine how there MUST be life out there and we will probably never know it or them

[Rawrishable]

We have so much left to explore, the possibilities are amazing and endless. Our world may seem large to us, but the scale and magnitude of everything around it- so hard to fathom.

[bbvibrabb]

Also this image shows what these galaxies looked like several billion years ago cause it takes light from those stars that long to reach us. We are looking into the past which is amazing

[morethanlyf]

wow, those are cool galaxies. thanks!:)

[zalida]

Sal, these vids are great - Thanks very much for making all of them.
Could you consider using a bigger cursor so it is easier to see where you are pointing on screen. That small cursor you use is difficult to see. i have seen you use an arrow-shaped cursor before that is easier to see.
Great stuff - Thanks

[axg]

This is amazing! Makes me think is this real? It's like people claim there is god, but no one can prove it. Same thing here, can anyone prove ever in "human life time" as you said that this does exist? Besides the images. Amazing stuff thank you for your videos!

[holychrist]

To think that in our 1 galaxy has life on one planet and if there are like millions of other galaxies out there, there is obviously life somewhere else its amazing !! :P

[DeluxeWarPlaya]

Least dense with instruction but most dense with inspiration

[Lucuskane]

@Taheki You made my day with that joke. I think he missed the one on the left too.

[lanog]

And I imagine an alien "KhanAcademy" talking about there point of view. How amazing. Space Engine is a great way to view the universe if we could go up to HUGE speeds (like 3 ParSecs per second)

[hweera]

And people laugh at me when I say that I believe there is other intelligent life out there...