Space Questions: Gravity's Pull, Cosmic Debris & Habitability Zones

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Heidi Campo: Welcome back to another episode of space

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nuts.

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Generic: 15 seconds. Guidance is internal.

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10, 9. Ignition

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sequence start. Space nuts. 5, 4, 3,

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2. 1. 2, 3, 4, 5, 5, 4,

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3, 2, 1. Space nuts. Astronauts

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report. It feels good.

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Heidi Campo: This will be a Q A episode where you, the

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listeners, have written in your questions and we

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will answer them for you.

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I am your host, Heidi Campo, joining you

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for possibly my last episode.

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We don't know quite yet. Andrew might be back

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next week, but if he's not, then

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I'll be back and I will say goodbye again.

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But until then, we still have, um, for now

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and the foreseeable future, we have our beloved professor

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Fred Watson, astronomer at large. How are you doing,

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Fred?

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Professor Fred Watson: Yeah, good to see you again, Heidi, as always.

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And, um, yes, this could be the longest goodbye ever.

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Couldn't it really? It could go on for weeks.

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Heidi Campo: It's like when you, uh, are parting ways with someone, you say goodbye and then

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you realize you're walking the same direction.

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Professor Fred Watson: Yeah, yeah, exactly. I know. Yeah. I do that all the

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time.

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Heidi Campo: And then I never quite know. It's like, well, do I keep talking to them? Do I say

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goodbye again? Do I pretend they're not there?

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I usually end up commentating and narrating the whole thing to make

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it more awkward.

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Um, well, anyways, let's just jump into

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our questions because you guys have some really

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fantastic questions, as always, which we

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appreciate. Our first question of the evening is a

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written question from John Kerr.

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And John says, hey, space nutters.

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This dilemma is driving me nuts. If the

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moon's gravitational pull has such an effect

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on our Ocean's tides, for example, a, uh, 30

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centimeter rise in tidal waters twice a day,

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that's a lift of 300 kg worth of water

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per meter square. Why doesn't the moon's

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gravity affect us as drastically as

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the oceans? I will sleep better once

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resolved with. Thanks.

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Oh, so I have so much. I have so much. I feel like I could say

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about this one too. But please get Fred.

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Professor Fred Watson: You might give a better answer than me, Heidi.

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Um, so it. Yes, well, it

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does. The moon's gravity does affect us as

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drastically as the oceans because we go up and down with the oceans.

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Uh, in fact, the land itself goes up and down

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slightly. If I remember. It's about a foot or something.

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Oceans sometimes go, uh, much,

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much more than that. Um, that 30 centimeter

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that John mentions.

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Uh, you know, sometimes it's many, many meters.

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So what's, um, happening here?

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It's. The critical feature of

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tides is that they are caused

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because of the difference in the

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gravitational pull of a body like the

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moon. And let's just think about the moon and the

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Earth. Uh, it's a difference between

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the moon's pull on one side of the earth

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and the other side of the Earth. So tides

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are all about the difference in the gravitational

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pull of an object, uh, across the

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diameter of another object, a big object,

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and that's the Earth. And so, um, the reason

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why our bodies don't stretch and shrink

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is that we're only, you know, we're only a

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couple of meters tall. Uh, actually my son's a

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two meters tall, but that's quite tall. All right, one and a half

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meters tall. But we're certainly not, uh,

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tens of thousands of kilometers, uh, which is what you

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need for the gravitational effect

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to be noticeable, um, as it is with the

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ocean tides. So we don't get stretched and

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um, shrunk. We would if we were near a black

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hole. That's the principle of spaghettification. It's when

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your feet feel a higher gravitational pull than your head head

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and you get turned into spaghetti. Uh, that's

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a uh, tidal effect, uh, an extreme

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tidal effect. But um, you need

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something very peculiar like a black hole to notice that.

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So for, ah, an object like the moon, we

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simply just go up and down with the oceans. If we're on

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the ocean, we go up and down with the land if we're on the land. But we

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don't get stretched and shrunk because we're too small.

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I hope he's Jonas. I hope you sleep better after

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that.

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Heidi Campo: Well, maybe I'll scare him because I was gonna say, but

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it does affect us a little bit. Not like the

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oceans at all. But the human body is

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roughly 60% water and every cell in our

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body is roughly 70 to 80% water.

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Now what I'm about to say next is not something

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I'm looking at a science review for. It's more anecdotal.

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But, um, nurses

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will all stay like often say

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that there is way more um, emergency

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room activity on a full moon. Police

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officers will say that people are crazier on a full

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moon. And there's a lot of lore

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around women's cycles aligning, ah,

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with moon cycles. Um, more women

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go into labor and give birth around the

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moon cycles. And

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historically there is a lot of

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um, I guess stories

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about personality around moons. You

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think of werewolf stories. So humans do. We are

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affected by the moon to some degree. And that would be

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an interesting, probably further research. And I'm

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sure there's whole departments dedicated to the

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psychobiological effects of humans and the

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moon. But it is interesting. So no we're not

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affected like the oceans but there is

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some, something to that.

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Professor Fred Watson: Absolutely. Yeah. And you, you, you're quite right. You know this

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natural cycles that align with um, with the moon

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and, and it's not just humans as well with things like

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coral spawning that's um, very much tied to

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lunar phases. Uh and some of that's not very well

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understood. Uh, but uh, I think the

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thrust of, of John's question is why,

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why aren't we being stretched and shrunk like the

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oceans are? Uh, perhaps I've got it wrong. But anyway that's the

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answer. Um, and I agree.

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Ben: Space nuts.

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Heidi Campo: Our next question is an audio

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question from Ben. Uh, with our

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audio questions. We like to cue those up so you the

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listeners can hear their question as well. I'm just

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going to give Fred a second to get his question ready as

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well and we are going to play Ben's question for

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you now.

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Ben: Hey guys, uh, it is Ben.

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Um, American, living in Mexico.

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Um, thanks for answering my last question about how

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observatories interrupt their observing

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schedules to deal with transient events. And

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I've just got a follow up question. Are there

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any, any um,

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scheduled observing things that uh,

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might be immune to these sorts of interruptions?

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Um, I know sometimes uh, there

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are time sensitive observations of uh,

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like transits or something um, that

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astronomers use to determine shapes of ah,

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objects and stuff like that that uh, need to

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occur at a specific time. So I was thinking maybe those are something

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that wouldn't be interrupted. Um, but

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yeah, that's my question. Thanks, loving the show.

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Voice Over Guy: Bye.

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Professor Fred Watson: That's a great question from Ben. Uh, and

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Ben's absolutely right and he's actually

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um, highlighted at least one of the uh,

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the reasons why you wouldn't interrupt observ. So

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um, his original question was about

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what we might call target of opportunity

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observations where uh, an observer on

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the telescope would stand

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aside if there was something like a

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supernova explosion, uh, that needed the

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same instrument uh to observe it to

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give us something that was only going to last for a very short time.

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And that happens a lot. Um, the,

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the, perhaps the best known of those

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was back in 1987 which I remember very

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well when that was the last time a

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naked eye supernova uh, went off

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in our skies down here in the southern hemisphere. It was in the Large

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Magellanic Cloud, our nearest uh, dwarf

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large dwarf galaxy. Uh, it was

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visible to the unaided eye first for 400 years.

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Uh and of course the Telescope, our

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telescope was only 10 years old then. It was state of the art

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and pretty well everything was pushed off for observations of

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this, of this object. Um, but

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um, it is usually

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um, you know, it's

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not usually uh, an event, uh,

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where there will be a

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conflict between the scheduled observer

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and the person who was requiring

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the target of opportunity observations.

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It's uh, usually the scheduled observer would have

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uh, uh, had an understanding at the outset

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that uh, they might need to stand

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by and um, let somebody

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else take over the telescope for the purpose

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of whatever their observations are. However,

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uh, Ben's absolutely right. There are some

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observations which are scheduled which

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themselves are time critical. And so

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you would rule out the telescope being

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taken over uh, for those events. Uh,

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one I was involved with, um,

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because I was astronomer in charge of the telescope at the time.

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And this is probably 10 years ago there was an

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occultation of Pluto.

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Um, so what that means is

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uh, actually it was an occultation of a star by Pluto. What

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that means is Pluto passed in front of a

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distant star, uh, and we could observe the

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brightness of the star. And what we wanted to

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do was look uh, at the way

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the star's light um, diminished uh,

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as it passed through Pluto's atmosphere. This actually it

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was before um, New Horizons flew

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by Pluto in 2015. So we

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didn't really know much about Pluto's atmosphere. It's very thin,

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very tenuous. But the observations that were made actually

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allowed us to um, you know, form

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details of it. In particular that it's quite layered. It's not a

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smooth, smoothly changing distribution. So that

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was very much a time critical observation. And you would

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not get uh, even if there'd been a bright

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supernova uh, in the sky that night,

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it probably would not have taken over the telescope. I think

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it would have, uh, the occultation

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by uh, Pluto would have been, would have been the thing.

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And as uh, exactly as Ben says,

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occultations are when an object passes in front of a

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star usually or another object. Uh, but it's a

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way of allowing us to work out the shapes of asteroids and things

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of that sort if they pass in front of a star. So

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that's really quite, quite important observations

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and very much time critical in themselves. So you wouldn't

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want them to be taken over by others. But it's a great question.

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Heidi Campo: It was a really interesting one. Yeah, it kind of gives us the inner

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workings of astronomy.

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Our next question, um, I'm actually going to read

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two questions because they are similar,

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but we want to get both questions

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perspectives. So the first one we're going to read

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is from David and David says

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hello Heidi and Fred. My question is

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regarding meteor showers and why we keep seeing them

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annually. If meteor showers such as

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Persidius occur when the Earth

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passes through the debris left behind by

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comets as they orbit the sun, what

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prevents the Earth from clearing the debris

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from our orbital path after the first pass,

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leaving our orbit free of debris until the next

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comet pass, uh, uh, next comet comes

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past. Cheers Dave.

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And then we have Brian with his

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question which is similar. And then

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Brian says, can you explain the orbital

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dynamics associated with annual meteor

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showers? We orbit the sun, but the

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whole solar system is rotating around the Milky Way,

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which itself is moving. So is the

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comet trail in a static stripe of debris

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which we bisect on the same point in our

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orbit total in our orbit each year

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or is it in the orbit of the sun

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or a galactic center or other?

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If it's in our solar orbit, why do we catch

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up with it? And why don't we effectively leave a

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hole in the debris diminishing the meteors

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every year from the dark state, uh,

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from the dark stars. North Yorkshire

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Moons National Park.

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Professor Fred Watson: Yeah, the national, It's North Yorkshire, um,

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Moors National Park. It's a place I know well in fact,

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uh, in the north of England and they do have dark

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sky, dark stars. Uh, this is from Brian there.

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I wonder whether Brian knows my friend Paul Cass who also

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works at the North Yorkshire Moors Dark

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Sky Park. Anyway, that's a different uh, aspect

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of all this Heidi. Um, and I might mention

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that um, they've uh. Dave who

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had.

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The other question was from, from Inverell here in New South Wales.

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So a question from the UK and a question from Australia,

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both effectively asking the same thing which I thought

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was uh, worth while bringing these

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two people together. So yes, the,

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the bottom line is, and you've got to sort of think of it in three

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dimensions, um, it is to do with

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the orbits of comets. Uh, a uh,

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comet moves in a usually

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a very elongated orbit. Um, and the sun

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is um, one end of um, uh,

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passes close to the sun and then disappears

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into the depths of the solar system. Uh, when it

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gets near the sun, uh, the comet starts

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basically projecting dust, uh,

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and that dust trail remains within

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the comet's orbit. And so those dust

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particles are sort of moving with the

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comet. They're um, moving in the orbit as well. But they smear

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out because they've got their own uh, motion.

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And so essentially ah, a comet

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leaves a trail of dust exactly in its

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orbit and if that orbit intersects the

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Earth's orbit, then the Earth will pass through the

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trail of dust. And that's exactly what it does.

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And when that happens, that's when we get a meteor shower.

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But the reason why, um, you know, it doesn't soak up

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all the dust as it goes through

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is because that dust itself is moving. Uh,

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and, um, it's not just a single dust cloud that

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you're punching a hole in. The dust is a

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stream of stuff that's moving through space with the same

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velocity, more or less as the comet had. Uh, and

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so what you've got is a region of space that's rich

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in dust, but it's being replenished,

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um, by the motion of the particles. So, yes,

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the Earth plows through, uh, doesn't really make a

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hole in it because, you know,

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we only sweep up, um, 12,000

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km diameter worth of it,

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because that's the Earth's diameter. Um, and the

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dust stream might be many, uh,

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tens of thousands and perhaps even millions of kilometers,

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uh, wide. Maybe not millions, but certainly

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tens, hundreds of thousands, possibly.

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So you've got a wide trail of dust that is

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a reservoir for the Earth to

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sweep up and see the meteor showers. So

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it's constantly being replenish. That's the bottom line. Uh,

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and hopefully that's the answer to both those gentlemen's

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questions.

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Voice Over Guy: Oh.

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Heidi Campo: Ah, that is fantastic, Fred.

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Generic: Okay, we checked all four systems, and.

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Heidi Campo: Being with a girl, space nuts, I'm getting sad.

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I'm gonna do my last question now. Unless. Unless I'm back next

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week. We will see. So

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backstory for. For um, those of you who might be new

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listeners, our regular host, Andrew. He's been on a cruise around

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the world and he's back now, but

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he has quite the conundrum. Uh,

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getting settled back in. We'll let him tell you all

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that story and him and Fred get caught up when. When he

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is back. But he's had quite an exciting time.

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All right, so our last question is. Excuse

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me. An audio question from Lou.

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Voice Over Guy: Hello, Heidi, and, um, Fred. My name is Noah from

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Manchester, England. I'm asking question

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about the Goldilocks Zone. The Goldilocks

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Zone is only habitable for life on, uh, Earth.

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For estrus rescues, however, they might need to

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exist at the very edge of the solar system or

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at the very center of it. Is the Goldilocks Zone

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nearly compatible for all life in the universe? Love the

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podcast. Hope you keep making more.

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Professor Fred Watson: Lovely question from Lou. Um, Manchester, again,

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a place I know well. I grew up not very far from

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Manchester in the north of England. So this has been a bit of,

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a, bit of a nostalgia segment for me.

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Um, but the great question, uh, you know, is

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the, is the Goldilocks Zone

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applicable to all extraterrestrial life? And

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I think the answer is no.

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Uh, because we, when we talk about the

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Goldilocks Zone, it's that region

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surrounding a star where the temperature is not too

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hot and it's not too cold, but it's just right for,

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for life to exist. It's why it's called the Goldilocks

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Zone. I've got a feeling it was a colleague of mine who coined that

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expression as well. A long, long, um,

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uh, it relies on the fact

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that we are, ah, beings. In

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fact, all life on Earth is

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uh, based uh, on water. We use water

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as our working fluid. Uh,

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as you mentioned, um, in our question on

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tides, Heidi, most of our bodies are made of

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water. Uh, and the same is

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true of most living organisms. Uh, water

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is a large part of it. And so

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liquid, uh, water is for us,

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uh, the,

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perhaps the strongest feature that

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um, might be used

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as an indicator of where life might form. If

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you've got water, maybe you will have life.

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That's always been the mantra. Follow the water.

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Um, so the Goldilocks Zone is where

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you could put a planet and it would be capable of having

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liquid water on its surface. Not frozen, not

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vapor, but liquid, which is what we need.

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So it's very specific is the Goldilocks Zone

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to um, life forms that are like

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ourselves, that are based on water and.

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Yeah, well, maybe if there is life anywhere else in the

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universe, it will be based on water. But there are other

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possibilities as well. And people have wondered whether

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perhaps the season lakes of Titan,

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one of Saturn's moons, uh, whether. Which

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are made of liquid ethane and methane, whether they

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might have, uh, living creatures in them

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that rely on those supercooled liquids

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as their working fluid. We don't know. We've not seen

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any evidence of that. But it is possible. And

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so if that was the case, then you'd be looking at entirely

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different type of Goldilocks Zone. If

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liquid natural gas was what you needed,

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uh, for these creatures, uh, then your

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Goldilocks Zone will be a very different one from

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the one that we have. It will be much further from your parent

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star. Uh, so Goldilocks Zones are not universal.

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They're not, um, kind uh, of, you know, common

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to all species because

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we don't know enough about what other species might be

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like. But it's a good start. That's why we look

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at the Goldilocks Zone with interest because the

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only life forms that we know use water. Uh,

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and Goldilocks Zone is where water might exist.

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So that's why we look there.

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Heidi Campo: Fred, have you ever seen that TV show, I think it's

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on Netflix or Amazon, called Alien

420
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Worlds, where they. They break down

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scientifically the conditions that would be needed for.

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For different life on different planets. Then they

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hypothetically come up with a planet

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that's a certain way. Have you seen it?

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Professor Fred Watson: M. I haven't, but it sounds like one that I ought to see.

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Heidi Campo: It's very interesting. And that might be one that

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Lou's interested in, because they come up with four

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hypothetical planets. One of them's a jungle, one of

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them's a desert. One of them is,

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um, the atmosphere is so dense

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that it's almost like water. So

432
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there's all these animals that look marine like,

433
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but they are like birds. And it's very cool

434
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just to play around because they use real physics

435
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and then talk about the hypothetics. It's kind of fun. Then I won't

436
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tell you about the last planet, because it's kind of a. It's a fun

437
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surprise. It's a fun surprise planet. It's not Earth. It's not

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Earth. Um, it's a very interesting

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hypothetical planet. Um, but I do recommend

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that show.

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Professor Fred Watson: Sounds great. I'll check it out. Sounds,

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Heidi.

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Heidi Campo: Yeah, it's a good one.

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Um, well, I guess that's it for our Q

445
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and A episode. So I just want to say, if this is my

446
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last episode, that it has been an absolute pleasure

447
00:21:21.730 --> 00:21:24.370
and delight being on here. Thank you all for your

448
00:21:24.690 --> 00:21:27.550
wonderful and kind questions. Fred, thank you for having me.

449
00:21:27.710 --> 00:21:30.270
If y' all want to stay in touch, you can follow me on

450
00:21:30.270 --> 00:21:32.710
LinkedIn. My. It's just my name, Heidi

451
00:21:32.710 --> 00:21:35.710
Campo, which is C, A, M, M, P, O.

452
00:21:35.710 --> 00:21:38.550
And then I think it's on. There is comma, C S, C

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00:21:38.550 --> 00:21:41.470
S, which is one of my certifications. That would be

454
00:21:41.470 --> 00:21:44.230
Comet sun, if we're spelling it phonetically.

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00:21:44.230 --> 00:21:46.990
Comet son. Comet son. So, Heidi Campos,

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00:21:46.990 --> 00:21:49.910
C.S.C.S. if you want to follow me on LinkedIn, I'm

457
00:21:49.910 --> 00:21:52.830
also on Instagram, but it's mostly just pictures of my dog and

458
00:21:52.830 --> 00:21:55.830
me talking about fitness stuff, which may not be everybody's

459
00:21:55.830 --> 00:21:58.520
cup of tea. Um, Fred, it's been a

460
00:21:58.520 --> 00:21:59.560
delight. Thank you.

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00:22:00.440 --> 00:22:03.160
Professor Fred Watson: Oh, it's been a delight for me too, Heidi.

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00:22:03.160 --> 00:22:06.040
And, um, I hope we do this again sometime.

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It might be next week, but. It might be next week.

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Heidi Campo: It might be next week. Yeah, we'll be in touch. And

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I'm. I'm always here if you need me. Um,

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till then, we'll catch, uh, you all next

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time.

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Professor Fred Watson: Take care.

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Voice Over Guy: To the Space Nuts podcast, Mission complete

470
00:22:23.400 --> 00:22:26.050
Eastern. Available at Apple, Apple Podcasts,

471
00:22:26.050 --> 00:22:28.650
Spotify, iHeartRadio, or your

472
00:22:28.650 --> 00:22:31.410
favorite podcast player. You can also stream on

473
00:22:31.410 --> 00:22:34.370
demand at bitesz.com this. Has been another

474
00:22:34.370 --> 00:22:36.450
quality podcast production from

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00:22:36.450 --> 00:22:37.570
bitesz.com