Happy birthday, Carl Sagan! The legendary astronomer, astrophysicist, cosmologist and science educator would have been 78 today. To celebrate, we've rounded up a handful of our favorite Sagan posts and curated some stellar content from other websites that are honoring him today. Feel free to contribute in the comments!

This recorded message from Sagan to future explorers of Mars will cold-cock you right in the touchy feelies

A few months before he died, Carl Sagan recorded a moving message which he dedicated to future explorers and settlers of Mars. A brief excerpt of that recording has been making the rounds on the internet since early Monday morning, in the form of the quote featured up top - but Sagan's entire message is a little more difficult to come by. We've tracked it down for you.

Read Sagan's letter (politely) telling Warner Bros. their Contact script sucked

We can see from the comments written in blue at the bottom of page one that character consistency –- what Ellie would or wouldn't do –- was at risk of becoming more anodyne and mealy mouthed. Lower on the page, Sagan mentions losing "the documentary" and its ability to economically express elements of the story. You can almost imagine how quickly both "the documentary" and the "carp/ant/squid POV" were removed from the original screenplay due to Hollywood's complete and utter terror that someone in a theater might be bored or confused for a moment. On page two Sagan raises important questions about emotional resonance and truth. Shouldn't, or wouldn't, the death of a character the protagonist loved be a big deal?

Neil deGrasse Tyson talks about his first time meeting Sagan

Turns out that when Neil deGrasse Tyson was applying to colleges in high school, Carl Sagan made an outstanding effort to make him feel especially at home at Cornell University, where he taught.

A speech from Carl Sagan that will make you cry

Are you familiar with the Sagan Series? Because holy crap, you should be. This is the video that started it all, and it's a veritable roller coaster ride of emotions and inspiration.

Brain Pickings: Carl Sagan On Books

Over on her Explore Tumblr, Maria Popova recognizes Sagan with a link to this Brain Pickings post about his love of reading. One of our favorites.

It's Okay to be Smart throws a Sagan GIF Party

The incomparable Joe Hanson also includes links to just about every Sagan post he's ever written ever. There are... more than a few.

Bad Astronomy: Carl Sagan Day

Sez the Bad Astronomer: I've written about him so much in the past there's not much I can add right now, so I thought I would simply embed a video for you to watch… but which one? Where James Randi eloquently and emotionally talks about his friendship with Carl? Or the wonderful first installment of Symphony of Science using my favorite quote by Carl? Or this amazing speech about how life seeks life?

But in the end, the choice is obvious. Carl Sagan's essay, "Pale Blue Dot", will, I think, stand the test of time, and will deservedly be considered one of the greatest passages ever written in the English language.

Universe Today: Remembering Carl Sagan

UT's Nancy Atkinson: Today would have been Carl Sagan's 78th birthday, and the past few years November 9th, the anniversary of his birth, has been designated as "Carl Sagan Day" by people who appreciate Sagan's influence - not only on science, but also the public's understanding of it. Sagan passed away 16 years ago, but his words and inspiration live on for many of us through his books and recordings.

Sagan was a co-founder of The Planetary Society, and this evening (Friday, Nov. 9, 2012) at 7 pm PST TPS [they'll] be webcasting a live event to commemorate Sagan's life and influence. Click here for the webcast link, as well as additional information.

TOR.com: The Cosmos Re-watch

Over at TOR.com, Brit Mandelo is leading a re-watch of Carl Sagan's Cosmos:

Cosmos: A Personal Voyage, consisting of thirteen episodes aired over the fall and winter months of 1980, is one of the most well-known, significant documentary series in the history of television-still the most widely watched PBS series in the world-and an emotional favorite for more than one generation of viewers, all around the globe.

I am not an expert; certainly not a scientist. What I am is an enthusiast, and a person with intense, personal memories of watching Cosmos as a child, of being inspired and moved by Sagan's narratives. The science in Cosmos may occasionally be outdated, but the passion isn't, and neither is the joy of sharing that passion with Sagan and the world's audiences. Cosmos denoted a moment in the cultural history of the US where folks had a lot to say, and think, about science together. I'd like to spend some time re-envisioning and re-investing in that conversation, along with you, readers, as we watch through the series once more (or, for the first time, if you've missed it) together.

Mandelo kicks things off with "The Shores of the Cosmic Ocean."