WEBVTT - Summer solstice listener questions

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<v Speaker 1>Hey, Daniel, what's the most distant object you've ever seen?

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<v Speaker 2>You know, the Andromeda galaxy is pretty far away. It's

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<v Speaker 2>like millions of light years. How about you, what's the

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<v Speaker 2>most distant thing you've ever seen?

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<v Speaker 1>When I am sleepy, it is my couch.

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<v Speaker 2>Your couch is far away.

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<v Speaker 1>Yeah, it's so fun.

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<v Speaker 3>W want mom.

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<v Speaker 4>Hi.

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<v Speaker 2>I'm Daniel. I'm a particle physicist and a professor at

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<v Speaker 2>UC Irvine, and I like to couch all my puns.

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<v Speaker 1>Hi. I am Katie Golden. I a podcast on animals,

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<v Speaker 1>and I am cushion for a never mind. I I

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<v Speaker 1>thought if I just said cushion that a pun would

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<v Speaker 1>come to me, and it didn't. It just made me

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<v Speaker 1>want to take a nap.

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<v Speaker 2>You were pushing for a pun, Cushion.

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<v Speaker 1>I thought I was going to be bruising for a

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<v Speaker 1>cruise in, but I was cushion for a pushing. I

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<v Speaker 1>guess a defenestration.

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<v Speaker 2>Sounds like you're set up for some punishment anyway. Welcome

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<v Speaker 2>to the podcast. Daniel and Jorge explain the universe in

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<v Speaker 2>which we try not to punish you. We try to

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<v Speaker 2>enrapture you. We try to share with you the joy

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<v Speaker 2>of understanding the nature of the universe, or when we

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<v Speaker 2>are mystified by the puzzles, the curiosity, the open questions

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<v Speaker 2>about the nature of this cosmos we find ourselves in,

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<v Speaker 2>we seek to understand it, we seek to explain all

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<v Speaker 2>of it to you.

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<v Speaker 3>On the podcast, Daniel.

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<v Speaker 1>Is this the one coming out on the summer solstice?

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<v Speaker 1>Just the quickest side before we get into our listener question.

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<v Speaker 1>I just visited in near Dublin, Bruno Boyne, these funeral mounds,

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<v Speaker 1>and it was so interesting because these very very ancient

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<v Speaker 1>people created these funeral mounds which had an internal structure

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<v Speaker 1>that they're large mounds like you could actually you can

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<v Speaker 1>go inside it. They can do ceremonies inside, and they

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<v Speaker 1>constructed it such that like during the solstice, the summer solstice,

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<v Speaker 1>on the longest day of the year, it illuminates this

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<v Speaker 1>entire inner chamber. And I just love that. So long

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<v Speaker 1>ago we were already thinking about physics, figuring out the universe,

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<v Speaker 1>and like trying to think about how light works and

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<v Speaker 1>use it for our interesting little Richard.

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<v Speaker 2>Yeah, exactly. I don't think that's a digression at all.

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<v Speaker 2>That's exactly what we're talking about today. People have been

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<v Speaker 2>asking questions about how the universe works, trying to make

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<v Speaker 2>connections with the cosmos. For as long as people have

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<v Speaker 2>been asking questions, all you have to do is look

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<v Speaker 2>up at the night sky and wonder, how does that

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<v Speaker 2>all work? Why does it seem so regular? Why are

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<v Speaker 2>their patterns? And then patterns within those patterns, what do

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<v Speaker 2>they reveal about the nature of the universe. Because one

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<v Speaker 2>of my favorite things about the universe is that it

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<v Speaker 2>does seem to follow laws, and we can figure those

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<v Speaker 2>laws out if we pay attention to those patterns and

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<v Speaker 2>try to draw dotted lines between them. And as you say,

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<v Speaker 2>people have been doing that for a long long time.

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<v Speaker 2>We sometimes dismiss our ancient history as like prescience and

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<v Speaker 2>only take things seriously if it's been figured out in

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<v Speaker 2>the last few hundred years. But you know, the development

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<v Speaker 2>of science is much more gradual than is often described

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<v Speaker 2>in history textbooks. People a long long time ago. We're

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<v Speaker 2>thinking methodically and trying to understand the universe, and that's

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<v Speaker 2>what people are still doing. And one of my favorite

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<v Speaker 2>things is trying to think deeply about the nature of

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<v Speaker 2>time and the universe. How far back in space can

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<v Speaker 2>we see, what do we see, and what do we

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<v Speaker 2>learn about how big and how strange the universe is

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<v Speaker 2>as we look into space. And so on today's episode,

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<v Speaker 2>we're going to be doing exactly that. We're going to

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<v Speaker 2>be answering a question a listener asked us about the

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<v Speaker 2>nature of deep time. So today on the podcast, we'll

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<v Speaker 2>be answering listener questions. Summer Solstice Edition. We're so happy

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<v Speaker 2>to be back and be back in your ear with

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<v Speaker 2>this special episode to celebrate the summer Solstice. Happy Solstice, everybody.

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<v Speaker 1>Happy Solstice. Enjoy your roasted pine combs and your chicken

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<v Speaker 1>feather damp and you're huge bonfires.

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<v Speaker 2>I hope you stay up late in the night, stare

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<v Speaker 2>at the stars, wonder about the nature of the universe,

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<v Speaker 2>and then write to me with your questions about it

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<v Speaker 2>questions at Danielanjorge dot com. Don't be shy, send me

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<v Speaker 2>your questions. You will get an answer. And on today's show,

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<v Speaker 2>we're answering a question from Nick in Florida, who's wondering

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<v Speaker 2>about the very oldest things we see in the sky.

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<v Speaker 2>Here is Nick's question.

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<v Speaker 4>Hey Daniel, this is Nick from Jacksonville, Florida. I came

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<v Speaker 4>across an article this morning that taught me something new

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<v Speaker 4>and amazing about the universe. Apparently, beyond the distance of

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<v Speaker 4>approximately fifteen billion light years, objects we see with telescopes

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<v Speaker 4>start becoming larger again instead of smaller. My question is

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<v Speaker 4>how close are we to being able to see this

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<v Speaker 4>far and what will be the implications for cosmology once

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<v Speaker 4>we get there? Thanks and love the show.

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<v Speaker 1>So this is really interesting. I have never actually heard this,

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<v Speaker 1>that objects that you see beyond a certain distance start

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<v Speaker 1>to appear larger, and I also don't understand how we

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<v Speaker 1>can see this far in the first place.

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<v Speaker 2>Yeah, it's really fascinating. It's one of my favorite facts

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<v Speaker 2>about the universe. It really shows us that the universe

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<v Speaker 2>is expanding and that we have a pretty good grasp

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<v Speaker 2>on how that works, or at least what's been happening,

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<v Speaker 2>which is already kind of astounding. The fact that wall

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<v Speaker 2>we've been trapped on this tiny little rock in one

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<v Speaker 2>corner of the universe, we can measure things that tell

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<v Speaker 2>us about the universe on the grandest scale. You know,

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<v Speaker 2>what's happening over billions and billions of light years, and

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<v Speaker 2>what's been going on over the last few billion years.

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<v Speaker 2>It's really incredible what we are able to piece together

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<v Speaker 2>from just the few photons that happen to land on

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<v Speaker 2>our rock.

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<v Speaker 1>That is wild. I mean, it's also just kind of

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<v Speaker 1>weird that in a way we can time travel, but

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<v Speaker 1>just with our eyes and some fancy shaped glass.

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<v Speaker 2>Yeah, it is really amazing. So there's a few different

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<v Speaker 2>things going on here that all come together to make

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<v Speaker 2>this really weird effect that if you can get them

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<v Speaker 2>all working together in your mind, show you how beautiful

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<v Speaker 2>our explanation is. So let's take them one at a time.

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<v Speaker 2>One concept is the one you just measured that looking

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<v Speaker 2>up into the sky is basically time travel, and that's

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<v Speaker 2>because the speed of light is not instantaneous. You know,

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<v Speaker 2>something happens in Andromeda, you don't see it right away.

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<v Speaker 2>It takes time for light to go from Andromeda to

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<v Speaker 2>our eyeballs. And so when we look up at the

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<v Speaker 2>night sky and we see Andromeda, we're not seeing what's

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<v Speaker 2>happening in Andromeda right now. We're seeing what's happening in

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<v Speaker 2>Andromeda when that light left Andromeda. And because Andromeda is

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<v Speaker 2>several million light years away, it means we're seeing photons

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<v Speaker 2>that left Andromeda several million years ago. Andromeda is not

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<v Speaker 2>even in the same place it was when emitted that light,

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<v Speaker 2>and so what we're seeing really is ancient history. And

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<v Speaker 2>the further we look out into the universe, the deeper

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<v Speaker 2>back in time. We are seeing like things are happening

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<v Speaker 2>out there in the deep universe right now, but we

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<v Speaker 2>won't see them for millions or billions of years, depending

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<v Speaker 2>on how far away they are. So as we look

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<v Speaker 2>out into the universe, we are really seeing further and

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<v Speaker 2>back in time just because of this simple basic physics

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<v Speaker 2>fact that light takes time to get to us.

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<v Speaker 1>So you're saying that if Andromeda has a newspaper that

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<v Speaker 1>is really huge that we can see with a telescope,

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<v Speaker 1>by the time that light reaches us, we're looking at

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<v Speaker 1>a pretty old headline. It is out of date.

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<v Speaker 2>Yeah, exactly. And conversely, it means that if Andromeda has

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<v Speaker 2>aliens that point their telescope at us, they're seeing millions

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<v Speaker 2>of years ago. They would see the Earth as it

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<v Speaker 2>was millions of years ago. They wouldn't even know that

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<v Speaker 2>there was an intelligent technological civilization on our planet for

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<v Speaker 2>millions of years, because that's only the very briefest part

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<v Speaker 2>of our history. And so somewhere out there are photons

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<v Speaker 2>from like when the Earth had dinosaurs on it, or

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<v Speaker 2>even further away, there are photons from the Earth when

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<v Speaker 2>it was like just a ball of magma. All those

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<v Speaker 2>photons are still out there in the universe. Somebody could

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<v Speaker 2>be picking them up where they're alien eyeballs and seeing

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<v Speaker 2>the ancient history of our planet.

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<v Speaker 1>I like to imagine that the reason aliens don't contact

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<v Speaker 1>us is they caught us when we had the weird

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<v Speaker 1>Anomalocaris that came marine explosion, giant disgusting shrimp looking thing,

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<v Speaker 1>and they're like, no, thank you, I'm not gonna get

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<v Speaker 1>in touch with that planet.

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<v Speaker 2>It's too icky.

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<v Speaker 3>Nah.

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<v Speaker 1>Yes, don't like shellfish seafood.

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<v Speaker 2>So that's one concept, right, Things in the sky are

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<v Speaker 2>old news. Right, We're not seeing the universe as it

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<v Speaker 2>is now. We're seeing the universe as it was. And

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<v Speaker 2>on one hand, that's frustrating because it means like we're

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<v Speaker 2>missing out on the latest, greatest news. On the other hand,

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<v Speaker 2>it's a huge gift. It means we can see back

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<v Speaker 2>in time and like on Earth, you want to know

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<v Speaker 2>what happened during the Roman Era or what happened a

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<v Speaker 2>million years ago, you got to look for clues that

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<v Speaker 2>happened to be here and be left over. Most of

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<v Speaker 2>that stuff is destroyed or buried, but in the history

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<v Speaker 2>of the universe, you just look into the sky. It's

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<v Speaker 2>all still there. It's just arriving right now, fresh as

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<v Speaker 2>the day was emitted. So you want to know what

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<v Speaker 2>happened in the universe a million years ago, or a

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<v Speaker 2>billion years ago or ten billion years ago, you just

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<v Speaker 2>build bigger telescopes to capture more distant, fainter photons, and

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<v Speaker 2>you can see it. It's all still they're in the sky.

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<v Speaker 1>So the further back in time we want to go

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<v Speaker 1>in understanding our universe, the further way look exactly.

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<v Speaker 2>So you have to imagine these shells, like in a

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<v Speaker 2>shell that's very close to the Earth, we're seeing the

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<v Speaker 2>more recent past. We can't see the distant past in

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<v Speaker 2>a close by shell, but we can't see the ancient

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<v Speaker 2>past in a more distant shell. So we can't just

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<v Speaker 2>like dial the knob and say I want to see

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<v Speaker 2>what happened over here at that time. We can only

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<v Speaker 2>see a certain time for every certain location because photons

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<v Speaker 2>are just now arriving from that location based on how

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<v Speaker 2>far away they are, all right, So that's one concept.

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<v Speaker 2>The other concept is how big things look in the sky.

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<v Speaker 2>And so to understand this first, let's just imagine the

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<v Speaker 2>universe is not expanding. Imagine that you have galaxies and

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<v Speaker 2>they're just hanging in space and nothing is moving. Everything

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<v Speaker 2>is just hanging there. There's no relative velocity. Then you

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<v Speaker 2>would expect things that are further away look smaller, right, because,

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<v Speaker 2>for example, if you have some galaxy and it's right

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<v Speaker 2>up in your eyeball, then photons from one side of

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<v Speaker 2>the galaxy and photons from the other side of the

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<v Speaker 2>galaxy are gonna come from very very different angles. Now

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<v Speaker 2>you move that galaxy further away in the sky, photons

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<v Speaker 2>from two different edges of the galaxy are now getting

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<v Speaker 2>closer and closer together, so they just seem smaller in

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<v Speaker 2>the sky. This is no magic. It's just like you

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<v Speaker 2>hold your finger close to your eyeball, looks big. You

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<v Speaker 2>push it further away, it looks smaller.

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<v Speaker 1>Right, It's just perspective, I see, Yes, So I have

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<v Speaker 1>been told that people from far away are not tiny people.

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<v Speaker 1>They are just far away. So all right, that makes

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<v Speaker 1>perfect sense.

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<v Speaker 2>Yeah, exactly, And we have an intuition for this exactly

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<v Speaker 2>the way you describe you don't think that people who

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<v Speaker 2>are standing next to you are giants and people who

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<v Speaker 2>are far away are midgets. You know this, and you

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<v Speaker 2>invert it in your mind. When you see people, you

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<v Speaker 2>can tell how far away they are, and so you

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<v Speaker 2>estimate their actual size because you've taken that into account. Right,

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<v Speaker 2>You have this intuition for things looking small far away

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<v Speaker 2>and things looking big close up, and you'll count for

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<v Speaker 2>this naturally. So if the universe was like that and

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<v Speaker 2>nothing was moving, then it would just look like that.

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<v Speaker 2>Things that are further away would look smaller. But there's

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<v Speaker 2>one more effect you have to throw into the mix,

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<v Speaker 2>and that's the expansion of the universe. Things are not

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<v Speaker 2>just hanging in space. There's a relative velocity there. Space

0:12:20.520 --> 0:12:23.960
<v Speaker 2>is expanding between galaxies, or another way to think about

0:12:23.960 --> 0:12:26.840
<v Speaker 2>that is galaxies are running away from us and from

0:12:26.880 --> 0:12:29.800
<v Speaker 2>each other, so everything is getting further and further away.

0:12:30.600 --> 0:12:33.199
<v Speaker 2>And what that means is that the light we're seeing

0:12:33.200 --> 0:12:36.600
<v Speaker 2>from those galaxies is not from where they are now,

0:12:36.960 --> 0:12:40.400
<v Speaker 2>it's from where they were when they emitted that light.

0:12:40.760 --> 0:12:43.959
<v Speaker 2>Oo okay, right, So, for example, imagine something on the

0:12:44.080 --> 0:12:46.800
<v Speaker 2>very distant edge of the universe. We talk about how

0:12:46.840 --> 0:12:50.040
<v Speaker 2>something could be forty five billion light years away, the

0:12:50.160 --> 0:12:53.839
<v Speaker 2>furthest things in our observable universe, all right, But when

0:12:53.840 --> 0:12:55.840
<v Speaker 2>we talk about that, we mean that's how far away

0:12:55.840 --> 0:12:59.559
<v Speaker 2>it is now, not how far away it was when

0:12:59.559 --> 0:13:02.120
<v Speaker 2>it admitted the light that's now coming to us, that's

0:13:02.160 --> 0:13:05.560
<v Speaker 2>now arriving on Earth. It was much much closer when

0:13:05.559 --> 0:13:08.480
<v Speaker 2>it emitted that light. What's happened in the intervening period

0:13:08.800 --> 0:13:11.760
<v Speaker 2>as that photon has flown through space towards us is

0:13:11.800 --> 0:13:14.760
<v Speaker 2>the universe has expanded and it's gotten further and further away.

0:13:15.000 --> 0:13:17.640
<v Speaker 1>Okay, So if I try to think about this on

0:13:17.720 --> 0:13:21.480
<v Speaker 1>human scale, you have various people standing out in a field,

0:13:22.240 --> 0:13:24.680
<v Speaker 1>and it's a very big field. So I need a

0:13:24.679 --> 0:13:29.880
<v Speaker 1>telescope for me to see people, and it's a telescope

0:13:29.920 --> 0:13:33.079
<v Speaker 1>with a slight delay, or a camera, let's say a camera.

0:13:33.120 --> 0:13:35.880
<v Speaker 1>It's got a delay in it, so I will only

0:13:35.960 --> 0:13:39.360
<v Speaker 1>see them after a while. So like, I could be

0:13:39.920 --> 0:13:43.280
<v Speaker 1>looking at these people who are further away, but then

0:13:43.320 --> 0:13:45.600
<v Speaker 1>the people who are closer to me, let's say they

0:13:45.640 --> 0:13:49.720
<v Speaker 1>are running away from me at a faster rate, so

0:13:49.800 --> 0:13:53.800
<v Speaker 1>they might with my delayed camera, look further away by

0:13:53.840 --> 0:13:56.680
<v Speaker 1>the time I get my snapshot than the ones who

0:13:56.720 --> 0:13:59.920
<v Speaker 1>were actually further away from me, but they look bigger

0:14:00.120 --> 0:14:02.880
<v Speaker 1>because they were not running away from me as fast

0:14:02.880 --> 0:14:03.319
<v Speaker 1>as the other.

0:14:03.480 --> 0:14:06.680
<v Speaker 2>Yeah, exactly, you have old information, and so you're taking

0:14:06.720 --> 0:14:08.880
<v Speaker 2>these snapshots and you're seeing people where they were when

0:14:08.920 --> 0:14:10.600
<v Speaker 2>the picture was taken. But if the picture takes a

0:14:10.600 --> 0:14:12.600
<v Speaker 2>while to get to you, by the time it does,

0:14:12.679 --> 0:14:16.679
<v Speaker 2>they could be much further away, right. And that's important

0:14:16.679 --> 0:14:19.640
<v Speaker 2>to think about because that affects how big they look

0:14:19.760 --> 0:14:22.480
<v Speaker 2>in the sky because when we talk about things that

0:14:22.520 --> 0:14:26.080
<v Speaker 2>are really really far away, we're seeing them remember as

0:14:26.120 --> 0:14:28.640
<v Speaker 2>they were when they emitted those photons, and if they

0:14:28.640 --> 0:14:31.520
<v Speaker 2>were much closer when they emitted those photons, they took

0:14:31.600 --> 0:14:34.800
<v Speaker 2>up more space in the sky because they were closer.

0:14:35.200 --> 0:14:38.400
<v Speaker 2>So those photons have been flying towards us those millions

0:14:38.480 --> 0:14:41.080
<v Speaker 2>or billions of years, but they started pretty close by, right,

0:14:41.280 --> 0:14:44.080
<v Speaker 2>So they started further apart because the thing was closer

0:14:44.080 --> 0:14:47.000
<v Speaker 2>to us. So there are two effects happening here. One

0:14:47.080 --> 0:14:49.680
<v Speaker 2>is things that are further away look smaller, right, But

0:14:49.720 --> 0:14:52.640
<v Speaker 2>the other effect is this expansion effect that some of

0:14:52.640 --> 0:14:55.520
<v Speaker 2>those things that are now really really far away were

0:14:55.720 --> 0:14:59.480
<v Speaker 2>closer when they emitted the photons. So these two competing

0:14:59.520 --> 0:15:02.360
<v Speaker 2>effects there. And so what that means is that if

0:15:02.400 --> 0:15:06.120
<v Speaker 2>we look at nearby stuff, mostly the first effect dominates

0:15:06.400 --> 0:15:09.000
<v Speaker 2>that things that are further away look smaller. So as

0:15:09.000 --> 0:15:11.760
<v Speaker 2>you look out into the night sky, stuff that's further

0:15:11.800 --> 0:15:14.760
<v Speaker 2>away looks smaller and smaller and smaller. But then there's

0:15:14.800 --> 0:15:18.280
<v Speaker 2>a point from about ten billion years ago when the

0:15:18.320 --> 0:15:21.360
<v Speaker 2>other effects starts to dominate. When we're seeing stuff that

0:15:21.480 --> 0:15:24.520
<v Speaker 2>was much closer when it admitted that light. Stuff looks

0:15:24.640 --> 0:15:27.360
<v Speaker 2>smaller and smaller and smaller as it gets further away

0:15:27.720 --> 0:15:30.600
<v Speaker 2>until about ten billion years into the past, and then

0:15:30.640 --> 0:15:34.000
<v Speaker 2>stuff starts to look bigger and bigger. So the oldest

0:15:34.000 --> 0:15:37.040
<v Speaker 2>stuff actually looks bigger in the night sky than some

0:15:37.200 --> 0:15:39.560
<v Speaker 2>of the closer stuff, some of the more recent stuff,

0:15:39.800 --> 0:15:42.120
<v Speaker 2>because you have these two effects that are competing with

0:15:42.200 --> 0:15:42.760
<v Speaker 2>each other.

0:15:42.760 --> 0:15:46.680
<v Speaker 1>Because we're basically seeing like an after image of something

0:15:46.840 --> 0:15:51.480
<v Speaker 1>that was going Yeah, it's actually not further from us.

0:15:51.520 --> 0:15:54.840
<v Speaker 1>I mean that the actual star is that was there,

0:15:54.960 --> 0:15:58.880
<v Speaker 1>but those photons that after image are finally hitting us,

0:15:58.960 --> 0:16:01.320
<v Speaker 1>representing where in the sky.

0:16:01.560 --> 0:16:03.320
<v Speaker 2>When we talk about the universe, we talk about where

0:16:03.360 --> 0:16:05.080
<v Speaker 2>things are now, that's where we put them in our

0:16:05.120 --> 0:16:07.800
<v Speaker 2>mental maps, but we don't think about where they were

0:16:08.040 --> 0:16:10.960
<v Speaker 2>when they emitted that light. And so if you just

0:16:11.040 --> 0:16:12.960
<v Speaker 2>line things up based on where they were when they

0:16:13.000 --> 0:16:15.800
<v Speaker 2>emitted that light, then yes, closer things would look bigger,

0:16:15.840 --> 0:16:18.560
<v Speaker 2>and further things would look more distant. But because the

0:16:18.600 --> 0:16:21.400
<v Speaker 2>expansion of the universe, not all the photons that are

0:16:21.480 --> 0:16:25.080
<v Speaker 2>arriving here are perfectly lined up with where things are now,

0:16:25.720 --> 0:16:27.840
<v Speaker 2>So things that are more distant now can actually look

0:16:27.880 --> 0:16:31.960
<v Speaker 2>closer than things that actually are closer still, so there's

0:16:32.000 --> 0:16:35.920
<v Speaker 2>this amazing effect in cosmology. And so Nick is asking

0:16:35.960 --> 0:16:39.920
<v Speaker 2>about this effect, and he's wondering, can we see this yet?

0:16:39.920 --> 0:16:42.040
<v Speaker 2>Can we see far enough out into the universe to

0:16:42.080 --> 0:16:45.000
<v Speaker 2>see this turnover where the really distant stuff starts to

0:16:45.000 --> 0:16:47.760
<v Speaker 2>get larger and larger again, and what does that mean

0:16:47.800 --> 0:16:51.720
<v Speaker 2>for cosmology? And the answer Nick is that yes, we

0:16:51.840 --> 0:16:55.000
<v Speaker 2>already can see that. We can see much further than

0:16:55.080 --> 0:16:57.920
<v Speaker 2>ten billion years into our history. We can see all

0:16:57.960 --> 0:17:01.000
<v Speaker 2>the way back to almost fourteen billion in years. So

0:17:01.040 --> 0:17:03.880
<v Speaker 2>we have observed this. This is not like a theoretical

0:17:03.920 --> 0:17:06.480
<v Speaker 2>concept that people are wondering about and going ooh, maybe

0:17:06.560 --> 0:17:09.400
<v Speaker 2>in the future sometime. This is something we see. We've

0:17:09.520 --> 0:17:13.200
<v Speaker 2>measured this, and this really nicely confirms our whole model

0:17:13.280 --> 0:17:16.440
<v Speaker 2>for how the universe is expanding and how that expansion

0:17:16.560 --> 0:17:20.600
<v Speaker 2>is accelerating. It's all encoded in the distances and the

0:17:20.640 --> 0:17:22.560
<v Speaker 2>intensity of stuff in the sky.

0:17:22.960 --> 0:17:25.200
<v Speaker 1>Did anyone come up with a theory that this might

0:17:25.240 --> 0:17:28.120
<v Speaker 1>be the case before we actually observed it, or did

0:17:28.119 --> 0:17:31.399
<v Speaker 1>we observe it and then come up with the theory

0:17:31.440 --> 0:17:32.000
<v Speaker 1>behind it.

0:17:32.119 --> 0:17:34.879
<v Speaker 2>Oh, yeah, great question. It al sort came together at

0:17:34.920 --> 0:17:37.960
<v Speaker 2>the same moment when we realized that the universe's expansion

0:17:38.160 --> 0:17:40.879
<v Speaker 2>was accelerating. We didn't even know that until we had

0:17:40.880 --> 0:17:43.800
<v Speaker 2>a solid way for measuring how far away things were

0:17:43.920 --> 0:17:46.560
<v Speaker 2>when they are really distant. We only figured that out

0:17:46.560 --> 0:17:49.200
<v Speaker 2>when we were able to calibrate type one A supernova

0:17:49.600 --> 0:17:52.240
<v Speaker 2>around the turn of the century, like twenty five years ago,

0:17:52.640 --> 0:17:54.879
<v Speaker 2>and that's what told us that the expansion of the

0:17:54.960 --> 0:17:58.280
<v Speaker 2>universe was different from what we expected. It's actually accelerating,

0:17:58.640 --> 0:18:00.840
<v Speaker 2>and that changed the whole picture. At the same time,

0:18:00.960 --> 0:18:03.520
<v Speaker 2>gave us a way to measure the distances to these

0:18:03.520 --> 0:18:07.120
<v Speaker 2>big things and showed us that distant objects are actually

0:18:07.280 --> 0:18:11.399
<v Speaker 2>larger than some nearer objects in our sky. And so

0:18:11.440 --> 0:18:13.240
<v Speaker 2>it all sort of came together about the same time

0:18:13.280 --> 0:18:15.960
<v Speaker 2>when we had this revolution in our understanding about the

0:18:16.000 --> 0:18:19.280
<v Speaker 2>expansion history of the universe. It's really nice confirmation of

0:18:19.320 --> 0:18:19.960
<v Speaker 2>that idea.

0:18:20.200 --> 0:18:23.919
<v Speaker 1>That's incredible. I mean, that must be so special as

0:18:24.000 --> 0:18:29.240
<v Speaker 1>a scientist to actually see these things that fit into

0:18:30.080 --> 0:18:32.119
<v Speaker 1>all of this theory and all all of these things

0:18:32.119 --> 0:18:34.480
<v Speaker 1>that you're discovering of like, oh yeah, there is visual

0:18:34.520 --> 0:18:36.280
<v Speaker 1>confirmation of this stuff at ward.

0:18:36.359 --> 0:18:38.440
<v Speaker 2>It's amazing that we can look up the night sky

0:18:38.520 --> 0:18:41.119
<v Speaker 2>and we can piece the story together from again, just

0:18:41.200 --> 0:18:44.400
<v Speaker 2>these photons and the patterns within them. And for thousands

0:18:44.400 --> 0:18:47.360
<v Speaker 2>of years, our ancestors desperately wanted to do that. They

0:18:47.440 --> 0:18:49.400
<v Speaker 2>looked up at the stars and wondered what they meant,

0:18:49.400 --> 0:18:52.520
<v Speaker 2>and found patterns, but never really had an understanding anywhere

0:18:52.520 --> 0:18:55.439
<v Speaker 2>close to what we have until very very recently. So

0:18:55.600 --> 0:19:00.680
<v Speaker 2>many people lived in such deep ignorance. Unfortunately, real blessed

0:19:00.800 --> 0:19:02.800
<v Speaker 2>to live in an era when we know anything about

0:19:02.840 --> 0:19:05.160
<v Speaker 2>the universe. But you know, I wonder about the deep

0:19:05.200 --> 0:19:08.080
<v Speaker 2>future when people will know so much more about how

0:19:08.119 --> 0:19:10.199
<v Speaker 2>the universe works, and wonder what it was like to

0:19:10.240 --> 0:19:11.879
<v Speaker 2>be as ignorant as we are today.

0:19:12.400 --> 0:19:14.920
<v Speaker 1>Uh, blissful is what I would say.

0:19:15.760 --> 0:19:17.480
<v Speaker 2>All right, If you're listening to this podcast in the

0:19:17.560 --> 0:19:19.720
<v Speaker 2>year three thousand know that we were dumb, but we

0:19:19.760 --> 0:19:20.320
<v Speaker 2>were happy.

0:19:20.560 --> 0:19:24.000
<v Speaker 1>We were dumb and happy. Take that future us all right.

0:19:24.040 --> 0:19:26.040
<v Speaker 2>Thanks very much to Nick for your question, and thanks

0:19:26.040 --> 0:19:28.760
<v Speaker 2>to everybody who wonders about how the universe works and

0:19:28.840 --> 0:19:30.840
<v Speaker 2>wants to figure it out. Please don't be shy to

0:19:30.840 --> 0:19:34.119
<v Speaker 2>write to me to questions at Danielandhorgheay dot com. You'll

0:19:34.119 --> 0:19:37.080
<v Speaker 2>always hear back. Happy Summer solsis everybody, and you'll hear

0:19:37.119 --> 0:19:44.640
<v Speaker 2>from us again soon. For more science and curiosity, come

0:19:44.680 --> 0:19:47.480
<v Speaker 2>find us on social media, where we answer questions and

0:19:47.640 --> 0:19:51.800
<v Speaker 2>post videos. We're on Twitter, This org, Instant, and now TikTok.

0:19:52.520 --> 0:19:55.320
<v Speaker 2>Thanks for listening, and remember that Daniel and Jorge Explain

0:19:55.400 --> 0:19:59.320
<v Speaker 2>the Universe is a production of Iheartwriting. For more podcasts

0:19:59.400 --> 0:20:03.360
<v Speaker 2>from my Heart Radio, visit the iHeartRadio app, Apple Podcasts,

0:20:03.480 --> 0:20:05.800
<v Speaker 2>or wherever you listen to your favorite shows.