Time Travellers [Carl Sagan Tribute Series, S01E18]

[ohio007]

"If we dont destroy ourselves" LOL

[Iamjustherek]

I find this video incredibly inspirational yet bittersweet at the same time. To make a trip in 28 years to you and return to your planet in its dying form is so sad to me :(

[xTheEmilyx]

@Iamjustherek Oh, me too. I almost cried :(

[Donal277]

Beautiful in every way.

[skyblazer7]

Wow, the ramjet animations are beautiful.

[Tbrown5526]

I'm ashamed to say I had no idea what Einstein's Relativity was about. Thank you Carl Sagan for putting into brilliant, innovative, and inspirational words. This video is amazing callumCGLP, thanks for uploading

[mzyzer19]

8394/7000000000

[apple2018]

I think were spending to much on military, time to invest in space!!! Let's get to work!

[myg0tBUTTPLUG]

@apple2018 I agree. Let's make that Hydrogen eating Rocket and Explore the Universe now!!!

[vulvoline01]

Im french canadian ... and we have noone like Carl in our culture ... eventually i did learn about all of what he says as best as i could and ... most of what he says isnt "new" to me .....

but the way he says it ... his voice ... I wish french canadian (im from Quebec) werent so defensive about their language ....

im 33 years old and ive only know about Carl Sagan for a few months .... i wish i could of known about him as a kid ....

Rest in peace carl ...

[vulvoline01]

as mentionned ... the soundtrack is from Ludovico Einaudi .... the track is "Rittornare" .... i think lol .... one of my all time favourite piano pieces ...

[InContemplation]

I dont understand, what exactly is preventing FTL speeds? Light is the fastest thing in the universe, but if slow-light is possible what's stopping artificial photon acceleration? Could some one please explain this to me?

[emikochan13]

@InContemplation The closer you get to the speed of light, the more energy is required to accelerate. To accelerate to the speed of light (if you have resting mass) takes infinite energy.

Much more feasible is bending space to achieve "ftl", that only requires the entire energy output of a large black hole or two ^_^

[Ryalnotch]

This one is one of my favorites :)

[TheMajorMicro]

neutrinos anyone????

[amarmirza08]

@TheMajorMicro probably bad data, give them time to confirm and figure it out

[TheMajorMicro]

@amarmirza08 yeah I know. But it would be cool if it was legit.

[amarmirza08]

It is amazing you keep finding these great narratives by Carl. Thank you so much for making these, it is both a inspiring and noble undertaking.

[N4SONIC]

Ok just when i thought i was starting to understand Space lol, the nearest star to us is 4 light years right, the centre of the milkey way 30 000 light years so how can you travel there in 28 years even going at the speed of light, the travel the full universe in 56 years also baffels me aswell as the furthest away galaxies are almost 13 billion years right ?, i understand these times are all "ship time" as time slows at the speed of light, any help would be great, cheers fellow sagonites ;).

[aeropostalbaby1]

@N4SONIC it's confusing. basically at the speed of light, you don't age. for you it would just be 28 years woth of time. but for all the people still here on earth, it would be 30,000. clocks tick more slowly and people age more slowly at light speed. everything else stays the same. hence the huge difference between 28 and 30,000

[N4SONIC]

@aeropostalbaby1 I understand that aspect of the speed of light, but to me if we were able to build a ship capable of going at those speeds, Alpha Centauri is 4 light years away and would take 4 years to get to, (ship time, travling at the speed of light), i get the 4 years to people not on the ship would seem a lot longer but it still doesn't explain how you could go round the whole universe in 56 year considering some of the galaxies are over 12 billion light years away, anyway cheers !.

[oceanhell2]

@N4SONIC Notice that Sagan said "56 years to circumnavigate the known universe" so I THINK he meant the universe that we have thoroughly discovered so far outside of our galaxy (which is probably not much) not the entire universe itself.

[johndobson01]

@oceanhell2 56 years shiptime, he meant.

[oceanhell2]

@johndobson01 So did I.

[marasu66]

56 years ship time to circumnavigate the known universe does not take into account the expanding universe. In real-time terms, that would mean 20-ish Gy of expansion unaccounted for. Traveling at those speeds would be hazardous, too, because every bit of dust in space could hit the vessel like a missile. On the other side, those left behind on Earth would be traveling near the speed of light with respect to our vessel as well, wouldn't they? since there are no privileged frames of reference.

[shackupyourstruly]

Oh! Since those left behind on Earth would be traveling near the speed of light with respect to our vessel as well, if we were to go to a nearby star system at relativistic speeds and then come right back, an observer on Earth would first see our vessel red-shifted as we go away, but, eventually, also see our vessel blue-shifted as we return, not after dozens or thousands of years, but for the "ship time" necessary for the round trip. Uh, when will threaded comments emerge from beta on YouTube?

[aeropostalbaby1]

@N4SONIC alpha centauri is 4 light years away. that means earth would see it as 4 years. in the ship would be a couple days.

[mzyzer19]

@aeropostalbaby1 How do you make the game show wrong noise on here?

[ZanVorez]

Why don't all of your videos have millions of views? I am sending them to everyone I know. If everyone does their part, the 6 degrees of separation should ensure most of the people on earth with internet see these videos.

[FreedomLiberty21]

callumCGLP, your videos are some of the best I've ever seen on YouTube [and I've been on here for 5 years xD ]

I think if Carl was still around, he'd be proud of you :)

Keep up the great work

Sincerely, your fan and subscriber.

[GodofSpanaway]

These videos really should be distributed to a wider audience, maybe played before movies, or on television. That would hopefully result in NASA getting a bigger budget.

[MrSupercat9]

Dear Callum, you could make 100 of these videos and I MIGHT be satisfied.... maybe. You honor Carl Sagan. He would be proud.

[pastorofdisaster60]

These videos, combined with the voice and ideas of Carl Sagan, are the most enlightening, (dare I say spiritual?) videos on youtube. You have my greatest thanks for posting these, as they have opened my mind in a way I have never conceived.

[Hoopmov]

Talk about time travel; every time i watch these videos i lose track of time and i travel to a future where i somehow love Sagan more than i last remembered.

[XTruth]

ANYONE NOTICED THE HALO 4 E3 TRAILER AT 6:17-6:28? INTERESTING

[rriverstone1]

Do you ever think: Sagan's body ought to have been "buried" in space, a la Hadden, in "Contact." I do.

[rsexplorer20]

@rriverstone1 Yeah does deserved to be in a grave traveling in space

[hermada]

After watching your tribute videos I need to turn away from the internet for a while. Everything just seems so pitiful, unimportant, marginal in the light of Sagan's wisdom.

Amazing videos.

[Toml420]

Relativistic space flight frightens me. The idea of accidentally or otherwise being catapulted into the distant future where the entire Earth is but a memory, with no hope of returning is one of my nightmares.

[bnbfav]

Thank you for the effort, dear uploader. These are great videos

[madjake170]

This always blows my mind! I love this Cosmos episode! I love this tribute video!

[N4SONIC]

Thank you for keeping the memory of the great Carl Sagan alive and well, for as long as there are people on our small blue planet his memory will never die, R.I.P old friend.

[kovyiscool]

this is so cool yet sort of depressing in a way

[nfhslugger]

That orion ship looks so cool. I bet we could solve the whole nuclear explosions in space thing if we just had conventional rockets take it past the moon and then start the big booms, safely away from home.

[d3st88]

@callumcglp

Your videos make me feel at home. In this world of ignorance and hatred I need this nourishment to keep me going.

I love how you match Sagan's wonderful ideas and voice with the perfect visuals and music.

[PorGaymer]

I love this Episode of Cosmos, Think of timetravel makes me always feel fuzzy.

[WindScar48]

I only want to thank you once again for your superb videos. They make me dream, dream of my home, the stars...

[marasu66]

If I were moving close to the speed of light with respect to the rest of my family, wouldn't they be moving close to the speed of light with respect to me, too? Wouldn't time dilation affect all of us? X(o:|]

[shackupyourstruly]

If they could see all the way to me, they would see me aging slower than they. If I could see all the way back to them, I would see them aging slower than I.

[MrWajax]

Truly amazing stuff!

[C507]

Amazing - keep it up I watch these almost every night laying in bed - simply awesome, thank you.

[d3st88]

@C507

Sometimes I play the audio versions of these in bed and fall asleep to listening them :)

[crownsedge]

My god, I fucking love Ludovico Einaudi :3

[FullAccessAgent]

One of the best yet. Great work!

[benblij]

instead of 28 years to the centre of the galaxy, they would measure it as 30.000 years.

WOW I just felt very small in a enormous galaxy.

[JamieTateJamieTate]

Fantastic!

[rriverstone1]

I don't know the jargon of digital audio, but I hear what I can only call a "pixilated" background noise. Other than that, good work.

[MarvelsofaLifetime]

Your videos aren’t just amazing – they are consistently amazing and keep getting better. I found this video to be the best yet. When I learned the fact that our species is actually capable of building machines which could reach other solar systems in a human lifetime… That just conferred so much emotional impact upon me, suspired so much hope.

[callumCGLP]

@MarvelsofaLifetime Just wait until you see the next episode, Telos. Oh my!

[WesleyLloydCarter]

@callumCGLP I cannot wait to see the next then. I thought after say, episode 13, they had to eventually stop being amazing. As it turns out I am very wrong, but what could I expect when you are working with such incredible material.

[rollofnickles]

Ah, Carol Sagan, I miss him so.

[Chatboy91]

Amazing as always!

[jneagu]

amazing video..I'm actually writing a script for a mainstream scifi/drama TV series based on this kinda stuff. I wish i can go in detail, but im afraid someone may steal my ideas. Great work man!

[MillenniumRequiem]

After Einstein put on his glasses in the beginning, and looked at the camera, didn't anyone else get chills? Like he was looking at you? Also nice video, there getting better! I want to be the few who leave, coming back a few thousand years later would be greta, by then aging might of been stoped biologically! By scientist!

[gtg737x]

This is absolutely beautiful. I sincerely hope that the 2013 Cosmos w/Neil Tyson has a scene like this in it's finale. For that matter, I sincerely hope that Dr. Tyson, Ann Druyan, Steven Soter, and Seth MacFarlane have seen your videos. Your work deserves their acknowledgement!

Your Tribute Series is always the most inspirational & well stitched together Sagan/NASA/Astro-science series on youtube, Mr. Callum.

[ndaltamirano]

So.. we cannot have an Orion starship because we signed a treaty forbidding nuclear explosions in space?

How can a nuclear explosion in space be harmful to anyone? I could understand forbidding "close to Earth" nuclear explosions.. even "close to our solar system nuclear explosions".. but "anywhere in space nuclear explosions"? Come on..

[CarnieKing]

Carl Sagan always makes me smile :)

[OpenYourMindandEye]

We need more people like Carl Sagan!!!

[callumCGLP]

My apologies for taking down the previous upload of this video, everyone. There were some dropped frames that snuck into my last render.

[ndaltamirano]

@callumCGLP Thank you very much for this amazing video!

[sathvikp]

@callumCGLP It still ends abruptly at 8:54 ...

[p2porkchop]

Ahhhh, waiting for youtube to process it!!! Can't Wait.