It’s been a few years since my last AMA, so we’re clearly overdue for re-opening a Cosmic Conduit between us. I’m ready for any and all questions, as long as you limit them to Life, the Universe, and Everything.


Comments: 8748 • Responses: 32  • Date: 


Life as we know it on earth is cell bases, DNA, and so on. If we did find alien life, are we sure we would recognize it? What if alien life is similar to iron, but our tests couldn't even detect some other unearthly element that makes it living. I guess my question is, since earth life is so unique and specific to us, how do weexpect to recognize "life" so unique and specific to another world? Could we have seen life on a planet millions of light years away, but not realized it because the details of photography are limited?

neiltyson9251 karma

Excellent question. We think life is alive and a slap of iron is not because, among a few other reasons, we have metabolism. We consume energy in the service of our existence. If we find any other entity that does this too, it would make a good candidate for life. Consider also that you reference and "unearthly" element. That is not likely at all because the periodic table of elements is full. There's no room for any other elements to be discovered in the natural universe. And using spectroscopy, we confirm that these very same elements are found in stars across the universe itself. Not only that, the four most common chemically active ingredients in the universe (H, He, O, C, N) are the SAME four most abundant ingredients in life on Earth. So our bias in searching for "life as we know it" is not entirely close-minded. -NDTyson

Shhhhhsleep5431 karma

Do you know you're the champion of r/iamverysmart ?

neiltyson3619 karma

Nope. Learn something every day. -NDTyson

K3R3G31087 karma

I used to really dislike him. Thought he was smug and obnoxious. Then I listened to him on Joe Rogan's podcast several weeks ago. He's actually cool. Listen to the man actually have a conversation and not judge him by factoid tweets and other similar snippets. I got you, /u/neiltyson. You're a bit misunderstood. Just trying to educate. Respect.

Edit: Added 6:55 EST, he replies to a comment where someone asks about him being an asshole.

neiltyson1127 karma

I don't mind being misunderstood. It simply raises my educational bar. Educators who are persistently misunderstood should not call themselves educators. -NDTyson

ThereIRuinedIt3129 karma

What is the most exciting thing going on with space exploration right now?

Either in recent months or planned in the near future.

neiltyson5870 karma

I think it's the multiple attempts of private enterprise to put their money were our dreams are. At that level, success is not as important as acting on the urge to explore. Lest we all ossify in the present. -NDTyson

monkeysrulz3085 karma

What's something you've learned recently that's really blown your mind?

neiltyson6160 karma

Lately I've had about one such incident per week. Although my target is one per day. I recently learned from some dynamicist colleagues that the striking visibility of Saturn's ring system is not eternal, coming and going with the dynamical forces of all that orbits the planet. Which means if I were around back when the Dinosaurs roamed and showed them Saturn through a telescope, it might have been an uninteresting sight. Very sad. -NDTyson

neiltyson2820 karma

6pm. Signing out now. Thanks for all your interest in this AMA. I reached only a fraction of you, but there were some good questions in there. Hoping my answers served this curiosity.

As always, Keep looking up. -NDTyson

iLikebigPayloads2215 karma

Dr. Tyson,

What advice would you share to an undergraduate of physics and mathematics who is very uncertain about a future career in science? Some nights feel defeating from the course work alone, but the thought of a future career based on my education can be overwhelmingly intimidating.

I have no intentions of giving up because I am certain of one thing: learning and applying science fills me with joy.

Thank you for your time and the hundreds of commuter hours I've filled with Star Talk


neiltyson7956 karma

I may be partly guilty for your scientific angst. Most of my public science persona involves conveying the joy of scientific discovery, and especially the joy of curiosity, from childhood through adulthood. What's commonly absent from my messaging is the steep investment of time and energy (physical and emotional) that becoming a scientist and actually doing science requires. In fact the struggle is what must be loved by aspiring scientists because being a practicing scientist requires this of you daily.

Not knowing the answer to a problem and struggling to find the answer is precisely what science is. It's neither more nor less than this. The fact that you are experiencing this very struggle is not a barrier to your progress it is the best evidence that you are on a path where you belong, if you love what you do.

Good luck. Sometimes you need that too.


wingnut5k1766 karma

How do you feel about the new NASA bill/budget?

neiltyson5919 karma

Wolf in sheep's clothes. My read of the (entire) plan is to remove Earth monitoring from NASA's mission statement. leaving NASA to think only about the rest of the Universe and not Earth as a part of that same universe. Unless this task is picked up by some other agency, the disconnect will be disastrous to our understanding of our own planet, preventing us from knowing and predicting our own impact on our own environment. My sense is that the next generation (30 and younger) does not think this way. They just don't happen to be old enough to be head of agency, corporations, or government yet. So I look forward to when they are all in charge. Especially anyone born since 1995 -- the year we discovered our first exoplanet. For that reason, I dub that demographic "Generation Exoplanet". -NDTyson

jackanapes81634 karma

Hello Neil,

I work at a Christian school. One of my co workers (the science teacher) was banned from showing cosmos. The administrators who banned it (due to a parent complaint actually) refuse to watch it to judge for themselves.

What would you say to them to convince them to change their minds or reconsider?

neiltyson3264 karma

In the USA, education is entirely local -- a surprise to most of the developed world. So a Christian school, or even a public school, could if they wanted to teach anything at all. It's just a matter of voting influence on a school board. If they fear the contents of Cosmos, they simply fear what science tells them about the natural world.

FYI: Galileo (a devout Christian) famously once said: "The Bible tells you how to go to heaven, not how the heaven's go.

So even he saw the line in the sand between the two. But this is 21st century America. And what matters here are the consequences of not teaching science to school children. Innovations in science and technology are the engines of tomorrow health, wealth, and security. So any school district that eschews the discoveries of science has disenfranchised itself from the future of civilization. They can still reap the benefits of it, but they will be paying to obtain (or gain access to) the discoveries of others, and no emergent industries will move their HQ there, if scientifically literate employees are nowhere to be found.


patopc19991328 karma

Hi Neil! Just wanted to know your thoughts on SpaceX's Falcon 9 relaunch and landing, and what do you think it means for the future of space travel? also, would you ever consider to join a one way trip to Mars?

neiltyson4230 karma

I really like Earth. So any space trip I take, I'm double checking that there's sufficient funds for me to return. Also, I'm not taking that trip until Elon Musk send his Mother and brings her back alive. Then I'm good for it.

Any demonstration of rocket reusability is a good thing. When we fly on a Boeing 747 across great distances, we don't throw it away and roll out a new one. Reusability is arguably the most fundamental feature of affordable expensive things. -NDTyson

wingnut5k1261 karma

What was the defining moment in your life where you thought "I did it?"

neiltyson3508 karma

I try to best every previous defining moment with a new one. In that way you don't live in the past, you live for the future. -NDTyson

realtyrionlannister1087 karma

Do you think we will ever make contact with complex organisms within the next 50yrs?

thanks for making my day.

neiltyson1433 karma

No. I think they (we) might all be too far away from one another in space and possibly time. By complex, I'm presuming you mean life other than single-celled organisms. Life with legs, arms, thoughts, etc. It's all about our capacity to travel interstellar distances. And that's surely not happening in the next 50 years. Not the rate things are going today. -NDTyson

FreddieFreeloader111055 karma

Hello, have you ever seen Rick and Morty? If so, what do you think of it?

neiltyson2614 karma

Embarrassed that I've never seen Rick and Morty. But I'm generally a fan of smart animation. And now that you've called me out, I'll put it on my list. -NDTyson

NedMalone1005 karma

What's your favorite book?

neiltyson2517 karma

As a middle-school kid: "One Two Three Infinity", by George Gamow and "Mathematics and the Imagination" by Edward Kasner and James Newman. On the fiction side, nothing compares for me to "Gulliver's Travels", by Jonathan Swift. Not the Lilliput story that we all know, but the rest of Gulliver's voyages. That's where most of the deep social commentary is embedded. In later life, I can't get enough of Issac Newton. "Principia", in particular. The most influential book ever on what we call modern civilization. It established the fact that the Universe is knowable and that mathematics is the language it uses to communicate with us. -NDTyson

A_Humble_Potato1002 karma

As someone who lives with very conservative parents who don't believe in climate change, what do you think is the best way we can reach out to deniers of climate change, anti-vaxxers, and those against GMOs?

Edit: it's MLB opening day! Who's your team??

neiltyson1956 karma

I'm born and raised in the Bronx, so I'm a legit Yankee fan. And as I Yankee fan, we're disappointed if we go a decade without a "world" championship.

As for your parents, ask them of they believe other things scientists have told them? That E=mc2 ? That their smart phone talks to GPS satellites, enabling them to avoid traffic enroute to grandma's house? That satellites warn them about weather pattern that could risk life or property?. If they are so skeptical of climate change, would they consider buying real-estate in very low-lying regions of the country, or the world? Do they know that insurance agencies are indeed listening to scientists? If none of that works, offer this short piece that i wrote. It's simply about what science is and how and why it works. Perhaps they never knew that emergent scientific truths are true, whether or not they believe in it. -NDTYson

jotarenan908 karma

What is the one question you wish we had the answer?

neiltyson2367 karma

I have a cop-out answer to that one. My favorite question to think about is the one we do not yet know to ask because it's very existence awaits our next discovery -- placing us on a new cosmic vista, requiring ideas and inquiry today undreamt of. -NDTyson

martinstormtrooper851 karma

What should we expect in the next few years from astrophysics?

neiltyson1631 karma

I'd love me some answers to what Dark Matter is, or Dark energy. I'd also like to know if there is or was ever life on Mars. These are realistically answerable questions in the next couple of decades.

In the immediate several years to come, there's an emerging cottage industry among planet hunters in which we can make measurements of the atmospheric chemistry of exoplanets. These amounts to a search for "bio-markers" such as Oxygen (O2), methane (CH4), and other signs of unstable molecule that could be made by a sustained biosystem on the planet surface. So watch for headlines there in the coming years. -NDTyson

lenojames532 karma

Hello Dr. Tyson!

I think I have an idea of what your answer might be, but I'll ask anyway. What are your thoughts and predictions on President Trump's executive orders regarding energy and the environment?

...and as always...


neiltyson1226 karma

Trying to get the Band back together on the Cosmos thing. Nothing green-lit yet. But we are all hopeful Lots of pistons need to align. Thanks for that interest.

As for Trump's Executive Orders, sixty million people voted for him. And he won US counties by a landslide. So if he did not do what he promised them (or what we all expected of him) then he would not be serving his electorate. Now, if he passes Executive Orders or if Congress enacts legislation that will disrupt the long-term stability of the country and of the planet, then the problem is not Trump, but your (our) fellow citizens who do not fully understand this problem and need to become informed (as is true for any voter) so that when we elect leaders, there is some correspondence between objective reality and governance. -NDTyson

KillerTapeWorm499 karma

Hi Dr Tyson, huge fan. I know its a big question, but how do you go on knowing how small we are in this universe? The thought of my insignificance in the grand scheme of things tends to depress me as much as the vastness of the universe interests me. Thanks for your time!

neiltyson2458 karma

Why should knowing we are indeed small in time, space, and size have anything to do with insignificance. Bacteria surely don't feel that way and they are billions of times smaller than us, yet they do most of our digesting. Ant's surely don't feel that way yet they likely represent nearly 20% of Earth's biomass. Why not instead think of how awesome it is that our 3lbs Human brain matter actually figured all this out. Why not look up to the clear night sky, and reflect on the fact that we don't simply live in this universe, but the universe lives within us -- through the atoms and molecules of our bodies, forged in the hearts of stars that long-ago gave their lives to the galaxy ... and to us. This is, of course, one aspect of the cosmic perspective that perhaps I and my astrophysics colleagues take for granted, but cannot be told often enough. -NDTyson

clusterdick375 karma

Will we find live outside Earth within 100 years from now?

neiltyson972 karma

Can't answer that, but I can give another kind of response -- I think in the next century we will know for sure whether there is or was ever life in the solar system -- especially on all the fun spot that keeps us wondering from afar -- Mars, Europa, Titan, Enceladus. -NDTyson

Bjarki56375 karma

Is science the arbiter of reality? If so what are some of the problems/limits of adopting that epistemology exclusively?

neiltyson843 karma

Science is the most effective thing Humans have ever invented to decode what is real and what is not in the world and the universe. If anybody every comes up with something more effective then we'll be all up in it. The limits, as I see it, are the occasional blind spots that result from looking for something we hope or expect to find, rather than for the unexpected. For this reason, in my field, when we deploy brand new telescopes we try to reserve time for them to enter a kind of serendipity mode, where it looks for anything, rather than what we seek. Big science is also driven by money made available by governments. So when conducted properly, it doesn't affect what is true but what kinds of discoveries of made -- possibly in the service of the state rather than in the service of the individual curiosity of the scientists themselves. -NDTyson

pezcone309 karma

You've said a black hole is the most interesting way to die in space. What is the second most interesting?

neiltyson804 karma

Hmm. Maybe a closeup view of a Supernova explosion. One of the greatest events in the universe. Happens maybe only once per century per galaxy. It would look beautiful up close, right up until until the energy intensity vaporized you. -NDTyson

Codiene288 karma

Neil, you're a great mind who helps reach out and bring many people new curiosity for science & I applaud you for that.

I am not as intellectually inclined as I wish I was but I feel confident as a good orator and communicator having worked sales jobs.

I don't believe I have the capabilities to go into a STEM degree so what do you think young people in my generation who cannot go into STEM should strive for?

also how'd you like the movie "Life"?

neiltyson1351 karma

What matters in society is not how many STEM professionals are running around. What a boring world that would be if we were all scientists and engineers. The world needs poets and artists and actors and comedian, and politicians, and even lawyers. What i see is that if you like STEM, but for whatever reason will not become a STEM professional, you can still gain basic levels of science literacy in your life, and blend that awareness into your work. This is already happening in the Arts. There's no end of art installations, sitcoms, dramas, screenplays, first-run movies, that have been inspired by science. Including The Martian, which helped turn the word "Science" into a verb, and Avatar, the highest grossing film of all time. So if your will not become a scientist yourself, then do not hesitate to allow science to serve as the artist's muse. Next in line -- scientifically literate politicians. -NDTyson

Cosmicpolymer265 karma

Greetings Neil,

I have looked up to you aside many others as you've stood as a figure of change and education in my life and the lives on in countless others. So here's my question.

Are you skeptical about the advances in high-pressure physics with the discovery of metallic hydrogen ?

With that being said do you think metallic hydrogen will replace liquid oxygen in our ambitious plan to reach Mars by 2030 ?

A pleasure for your time,

Thanks Anthony.

neiltyson460 karma

Metallic hydrogen is not a new idea or concept. It's actually why on the Period Table of Elements Hydrogen typically appears on both the left and right side -- with metals (on the left) and with gases (on the right). In any case, whenever we enter the domain of new element behavior or new molecular properties, it's just a matter of time before new and cool applications follow. So I have no crystal ball, other than to say that in the hands of clever engineers and artists, cool things come from cool scientific discoveries. -NDTyson

Bignosedjimbo196 karma

A lot of people have anecdotes of meeting you and claim that you're an asshole in real life.

Can you confirm these stories? Or give any excuse as to your behaviour?

neiltyson431 karma

Wow. I wonder how many people that is. Or rather, I wonder what fraction of all people I've met feel that way. (That's surely a more useful datum than the absolute number.) I may be delusional, but I'd guess it's less than 1 in 1000. It think my public persona greatly resembles my private and my one-on-one persona. Anything other than that requires huge investments of energy.

I don't mind being thought of as an asshole if in fact my behavior deserves it. I note that I had just such an encounter with a journalist from Idaho, who write an article titled "Neil deGrasse Tyson is a horse's Astrophysicist". I had actually never met him. And he based everything in his article on things that were objectively false. When I publicly called this to his attention, many of his colleagues and friends mocked him for his sloppy journalism and he ended up leaving his job. So there may be strong urges out there for people to think this way. But I wonder how much of it is based on reality and how much of it derives from people's need to hate.

Another question back at many genuine assholes devote three unsolicited hours to purely answering questions from the public about anything at all? -NDTyson

cuck_lord_94150 karma

Do you think advancements like those being made at space-X will have meaningful impacts on our goals to go to Mars within the next decade or two?

neiltyson371 karma

I'm simultaneously one of Space-X's biggest critics and supporters. I've said many time and many places, e.g. that projects that are hugely expensive and dangerous, with uncertain returns on investments make poor activities of profit-driven companies. Governments do these things first, allowing private enterprise to learn what to do and what not to do, then come next with a plan that involves us all. So my read of history is that private companies will not be the first to send humans to Mars unless government actually pays for it. -NDTyson

Mancue131 karma

Who are your favorite philosophers? Do you think philosophy is still relevant today?

neiltyson279 karma

Francis Bacon is up there. I recently came across a book of his that was filled with accounts of experiments he conducted, which may have informed his important philosophical conclusions about the value of experiment in finding scientific truths. This was around the same time as Galileo, who arrived at the same conclusions. Of course back then, "Natural Philosophy" was practically synonymous with what today we call Physics.

In the 20th centruy, when the atom revealed itself to our experiments, and the expanding universe entered our largest telescopes, it made philosophizing about the natural world harder than before, where now, what's true no longer issues forth from our senses.

Experiments matter. And if you do experiments, we generally call you a scientist and not a philosopher.

Plenty of philosophy frontiers abound, including Moral & Ethical Philosophy, Political Philosophy, Religious Philosophy. And there are still-emergent fields that could benefit from some smart ideas about where they should look next, especially in studies of consciousness, neuroscience, and ecology. -NDTyson

theflamingskull129 karma

On the set of Zoolander 2, did you get the opportunity to smoke with Willie Nelson?

neiltyson469 karma

yes, i did have a cameo in Zoolander 2. But Ben Stiller made me do it. Especially the end scene, rendering my face as the last thing you see in the film:

But no, we were all (the cameo celebs) choreographed to come on and off set in pre-set timeslots. There was not a single room where we all hung out, waiting to be called. I did overlap with Billy Zane and we've become fast friends.

So my answer to your question is no, I did not get high with Willie Nelson on the set of Zoolander 2. -NDTyson

smoke_and_spark100 karma

How bound is our society to thermodynamic entropy? If elected to supreme leader, how do you purpose we deal with the effects of entropy on humanity.

neiltyson379 karma

Entropy is not the enemy people might be led to believe All it takes is a source of energy to reverse it. Earth is not a closed system. We receive energy daily from the Sun, which empowers the chemistry and life of our planet to grow complexity -- against the wishes of entropy. Consider, however, that the Sun-Earth system, taken together, loses energy and gains entropy. And the entire universe itself is on an one-way trip to entropic oblivion, ending not in fire but in ice, and not with a bang, but with a whimper. Have a nice day. -NDTyson

CharizardKilla14 karma

Excuse my ignorance but what exactly is it about entropy that we need to deal with?

neiltyson27 karma

People worry that entropy will run away with us, reining this ordered world into a disordered mess. Some decades ago, non-physics-fluent religious groups cited the second law of thermodynamics as reason for why Evolution -- where simple organisms evolved complexity over time -- could not be true. When they finally learned that Earth is not a closed system -- open to energy from the Sun -- this argument faded. -NDTyson

bags0candy55 karma

What are some personal or career goals you haven't yet achieved?

neiltyson243 karma

To foster an entire generation of scientists as educators so that I can fade away and not even be noticed for having done so. That's would represent a stunning future of science literacy in the land. That's a career goal in the sense that then I can return to the lab and publish research papers again. That's my possibly delusional career goal at this time in my life. -NDTyson