Hey smart people, it’s been a while since
we did one of these, and there’s a lot of new faces out there. To celebrate our two
millionth subscriber, I’m here to answer two million of your questions. Grab a cup
of coffee, we’re gonna be here for a while. As always, you’ve been sending in a lot
of comments and asking great stuff. Like How’re y’all doing today? (Jameson
Moore): First off, is “how’re” a real word? Let’s argue about it in the comments.
Secondly, great and thanks for asking. Congrats on having 2 million subscribers (Adarsh
Kumar): Yeah, that happened. Thank you! And thank you to the other 1,999,999 of you that
helped us reach this milestone, which I know is just a random and convenient divisible-by-10
number, but is still completely mind-boggling and awesome and I feel very lucky, so seriously…
thank you times 2 million. Which is your favourite video you’ve made
and why? (Inés Laura Dawson): Favorite video? For YouTube creators our videos are like our
children, and would a parent say they have a favorite child? No… but they would think
it, because they secretly DO have a favorite. I’ve posted over 200 videos up to this point,
and my favorite one? Is probably this one (blue ice cave). I would live in that ice
cave, if it wasn’t so cold, and wet… and full of dangerous falling rocks. That cave
is just flat-out one of the most beautiful and interesting things I’ve ever seen (besides
my wife)… How did you get into the video-making game?
How did you get started with video production/did you ever have doubts about how it would turn
out? (Elaine Greywalker, Mitchell Davis): I don’t think I’ve ever told this story
on the channel before, and everyone keeps asking, so here goes. I got a degree in biology
from here, I did some research, went back to get a Ph.D., also from here, and while
I was learning all this awesome science I realized a lot of people out there weren’t.
So when I taught biology in grad school, I started playing videos from these people,
which inspired me to make my own website so I could share awesome science with everybody,
and at the top I wrote this motto, to remind people that it’s okay to be smart, didn’t
really mean for it to be the name, but people started calling it that, so that’s how that
happened. Blog got REALLY popular, so I decided to become a better science writer, I worked
there for a summer, and in the middle of it all I got an email from these people asking
if I wanted to make some science videos. I said “sure, never done that before, why
not?” and definitely don’t go back and watch my first videos. SIGH. In the beginning,
like everyone else I just turned on the camera, tried to tell a good story, and worked to
be a better writer, teacher, and creator every week, by listening to you and being inspired
by fellow creators. And 5 years later, thanks to the wonderful, creative people that help
me research and write and animate and produce these videos, we’re having a lot of fun.
Do you write your own puns? (Luis Mijango): Of course I do! Using a ghostwriter? That
would NOT be ghoul. What’s your favorite science podcast for
kids? (@TumbleCast): Excellent question, Tumble Podcast. Have you heard of Tumble Podcast?
It’s really good. Advice on relationships? (Ashraf Ansari):
If you love yourself when you’re not in a relationship, you’ll love a lot better
when you’re IN a relationship. Think about what you can give more than what you need.
And don’t worry about it lasting forever, just focus on being happy right now, because
a few billion years from now the dying sun will swell up and vaporize Earth anyway.
Will we ever see your wife be a guest on your show? (Force_Sensitive_Tree): (shrug)
If a chicken had lips, could it whistle? (Cameron Crielaard): Not like we do, because whistling
involves highly coordinated tongue movements and breath control, and birds tongues are
tiny and weird, and they actually don’t even have diaphragms. Srsly you should look
up how birds breathe, it’s weird, they’re like living bagpipes. But birds don’t need
to whistle anyway, because they have this cool organ called a syrinx, which is kind
of like if our voice box was in our chest, and they can squeeze air through it to make
all kinds of whistling, chirping, quack-a-doodle-doodling noises that are way cooler than (whistle)
like this. Do you have any advice for others who would
like to be science communicators? (Jeremy Klein, also this tweet): There’s a lot that
goes into communicating science well, but the most important thing to remember is while
we like to think of science as a big pile of stuff to know, it’s really a way of looking
at the world. People like stories more than data, and the best way to get someone to think
about something is to make them feel something. Always remember: while facts are often simple,
people are complex. Any advice for science grad students? (Abdel
Halloway): Take time for your mental health next to all your hard work. Your value as
a person is not tied to the success of your science. And remember, you might sometimes
feel like you don’t belong, but you deserve to be there, and everyone else is just as
anxious and confused as you are, they’re just not admitting it. I wish someone would
have told me this when I was in grad school. Show us your baby! (Sa Sa4) Ok! He’s the
best. Light pollution please! (Nicole Rodriguez):
Ok! (Oh, did you mean do a video about it? Good idea!)
How did you decide you wanted to work in biology? (Luiz de Paula): I think I’ve answered this
before, but there’s this saying that “all science is just applied physics” and and
physicists think they’re the coolest… but to that I say without biology, there wouldn’t
be physicists. Checkmate biology. A few people have asked if there was a place
they could send stuff to me and the show, like real physical stuff. And the answer is
yes! Details down in the description. You guys have also been really active in the
youtube comments on every video, which is great. So now, against my better judgment,
let’s read some those comments from a few of our favorite
recent videos, which you should go watch right now. I’ll wait. First off, to address the most common comment
I got. Yes, I’m aware that the sky and the ocean are blue, but I didn’t include them
in the video, because the sky and the ocean didn’t *evolve* to BE blue, like living
things did, so I didn’t include them. Because I’m a biologist, and living things are more
interesting. Also, because this is my channel and just because.
A couple people wondered what makes pigments different from structural colors (Victor Souza,
Mjester12) : Part of the problem is that when we say molecules have structure, or that a
butterfly wing has structure, we’re really talking about different things. One’s a
way to describe how atoms are arranged, like the structure of water. The other is the actual
physical shape of some thing, like how your house or face has structure. Ok, so white
light is a mixture of all colors, all wavelengths in visible part of spectrum. If we see something
that has color, that’s because the color or colors we see are reflected to our eyes,
and the object subtracts the other wavelengths. Difference is, that when a pigment absorbs,
the energy of a photon, if it’s the right wavelength, is literally absorbed, like a
sponge, except the sponge is usually an electron. But in a blue wing, or feather, wavelengths
get trapped inside like a hall of mirrors, and cancel each other out, like we showed
in our video. So pigments work in a very different way, one that requires special chemistry,
and that’s why nature found it was easier to make blue with shapes instead.
Carotenoids (Top Fertilizer): If we eat too many carotenoids can we turn pink? Well, no,
not pink. But I was amazed to find out, you could turn another color. If you eat enough
plant foods like carrots, sweet potatoes, squash and other colorful veggies all naturally
high in carotenoid pigments, you could develop a condition called carotenemia, where patches
of your skin actually turn yellow or orange. It’s most common in small kids or babies,
when their parents are shoving mashed carrots and stuff in their face, so obviously as an
adult you’d have to eat A LOT of the stuff. Usually not harmful, though. The cure is to
just stop eating those foods. Cheeseburgers for health! Salem Al-Arrak comments that reading about
evolutionary stable strategies, like sex ratios, in Richard Dawkins “The Selfish Gene”
really shifted their perspective. That book is the first place I learned about this idea
too. The Selfish Gene discusses a lot of what we’ve learned about evolution since Darwin,
and it’s a great book. We’ve actually got a whole website full of books that we’ve
featured in past videos. Go read and learn you a thing.
Joshua Walters had an excellent question about purple people eaters and what they eat. They
clearly are purple and eat regular people, because if they only ate purple people, they’d
starve, because not a lot of those around. Exceptions (Actung Daniel), Ants/bees (Szenanners,
JoJo Garcia, Aria Bane), Temp-determined sex (Das Ganon). We’ll try to do a video about
that in the future. David Lazure left a great comment about how
I distinguished sex vs gender in this video, Actually, a LOT of people commented about
this, but most of the others weren’t this polite. I want to take a moment and address
this. So, why would I, a scientist, differentiate sex from gender? When people talk about these
things in day-to-day life, the words are sometimes used interchangeably, which has led to a lot
of confusion. But when biologists discuss sex, we’re referring to combinations of
DNA, chromosomes, and how those genetic instructions influence physical characteristics. Gender
is a much different thing, that deals with how different societies in different places
have developed expectations or traditions for how people act in relation to their appearance
and their sex, and a whole lot of other things. Sex and gender ARE different things, no matter
what your feelings are about how they’re used to describe people. Since my video was
about genetic sex, it was important to me to make that clear. Scientists are starting
to ask a lot more questions about sex and gender, and there’s a lot more to talk about
here. Maybe we’ll come back to it in the future. HIV (Juan Kentoy): So HIV actually attacks
a completely different type of immune cell, T-cells, and the kind of antibody-producing
cells I talked about in that video are B cells. There’s one group of T-cells that actually
helps B cells attack germs, they sort of amp them up and help the B cells do their job,
and that’s the cells that HIV kills, and that’s why HIV weakens people’s immune
systems. But HIV is super interesting and there’s a lot to talk about there, so maybe
we should do a video about that too. Lots of video ideas!
Muscle memory/autoimmune diseases/neuro-plasticity: This video seemed to give you guys a lot of
ideas for other videos. These are all super interesting topics that there’s no way I
could do them justice right now, but I love suggestions like these so keep them coming. Water use (Feynstein 100): Had an interesting
comment about how much agriculture really can be scaled up in order to feed more people.
The truth is, no one really knows for sure, because we don’t know what will be possible
with tomorrow’s technology or in tomorrow’s climate. But what’s certain is we’ll have
to feed that population differently than we do now. According to the World Bank, 70% (!!!) of
freshwater that we use on Earth goes to agriculture, already! So while there is some land like
deserts where we’re not growing stuff already, we don’t have extra freshwater to make that
into farmland. Gonna have to be a lot more careful with what we plant where, to make
best use of water, and even consider developing crops that use less water, which is a whole
GMO question that we should probably talk about one of these days.
Burden of old age (Wan Ahmad Firas): This is another really interesting side of the
story that we didn’t talk about. Birth rates actually slowing in most of the world, and
most of Earth’s population growth is from people just living longer and not dying as
much as they used to, rather than rapid growth in the number of people being born. So as
science continues to fight aging or even gets close to beating it, we might have a whole
new population question to deal with. Finally: Moon cheese (Ira Iguanadon): Now,
the moon is NOT made of cheese, it is actually made of rock, and covered in several inches
of dust particles that haven’t been smoothed out by wind and erosion like dust here on
Earth, sharp as glass, and which would definitely kill you if you ate it. But if it WAS made
of cheese… well, the moon is roughly 22 million–million-million (22e18) cubic meters
in volume, which is the volume of roughly 720 million-million-million wheels of Parmigiano-Reggiano.
If all 7.6 bn people on Earth ate 27 kg of cheese every year, as much as your average
French person, then it would take approximately 133 billion years for us to eat that cheesy
moon. So, that’s around two million, yeah? Great!
These were all wonderful comments and questions, and we appreciate all your support and curiosity.
There’s a ton I didn’t have time to answer, but you can always find me out there on the
internet. Thanks and remember… Stay curious.
