Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / #412: Cosmic Queries: A Voyage to Voyager & Defending Astronauts Beyond Earth

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#412: Cosmic Queries: A Voyage to Voyager & Defending Astronauts Beyond Earth · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Hi there, thanks for joining us on a Q and A edition of Space
• 0:04
  Nuts. I'm Andrew Dunkley, your host once again. Thanks for joining us
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  and good to have your company on this edition. We're answering some questions about
• 0:13
  light in space. This one comes from Lee's asked a very interesting question.
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  I've never actually thought about this particular concept, but it's a question that I
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  think is worth answering for sure, That's why we included it. Fenton wants
• 0:29
  to know about shielding astronauts in the outer reaches of the Solar System, and
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  he's got an idea on how to do that. Robert wants to talk about
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  things we learned from the Moon and what if our moon wasn't the same as
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  the Moon is now, would our learnings be different. That's a really interesting
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  question. And Duncan wants to talk about ice giants and why are they ice
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  giants? Why don't we call them something else? That's all coming up shortly
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  on this edition of Space Nuts ten nine ignition Space Nuts or three two Space
• 1:10
  Nurse as when I we bought it. Bill's good. Once again, we
• 1:15
  welcome the one and only Fred. What's an astronomer? At Tello? Fred?
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  Hello and how have you been since we lost I haven't moved from this
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  seat you all that time? Well, it's I can see you glued to
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  your chair there very much. So shall we get straight into it and answer
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  some questions from our audience? We will, it is that's what we're here
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  for. This first one, Fred comes from Lee. He lives in New
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  York City. He's asking how much light is in space? You'll qualify that
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  question. For example, if you were to visit Voyager one where Voyager one
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  is today, would you be able to see it? Would you see just
• 2:02
  a silhouette? Would you be able to make out details and colors if there
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  are any colors on it? What about if you and voyage were midway between
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  the Sun and Alpha Centauri. Can we know a reasonably accurate answer or is
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  it pure speculation? Thanks love the show. Lee from New York, I've
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  never thought about that. I mean, we take for granted light on Earth
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  because we're illuminated by the Sun, but it's a bit different in other parts
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  of the Solar System and the universe in general. So yeah, if we
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  could just go snap, we're out there next to Voyager one, could we
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  actually see it? Is it illuminated in any way. Is it being illuminated
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  by something? What would it be like? The answer is yes, you'd
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  see it. And so we're talking really now about the sensitivity of the human
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  eye, because with a camera, you know, with the long exposure settings
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  and things, you'd be able to see in great detail. But thinking about
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  the human eye. So I used to work, as you know, signing
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  Spring Observatory. I spent many hours outside at night. There. It is
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  a place that is truly dark. There's no interference from street lights. There
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  are a few blobs of light on the horizon, but nothing that affects the
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  pristine darkness of the night sky. And on a starry night, with the
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  sun not in the sky, you can see quite clearly. There's enough light
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  from the stars themselves to let you see where you're going, let you walk
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  around and be quite confident that you're not going to fall off the mountain,
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  as I nearly did one night when it was cloudy. I went out without
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  my torch and thought, oh yea'll see by the stars. But fortunately,
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  unfortunately the cloud had come in. I could see anything, and I nearly
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  fell off the mountain. I didn't in the end, but a long drop
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  three. Yes it is. Yes, it's quite a long drop anyway,
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  if you you know, normally on the starry nights, you will see by
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  the light of the stars. Now, where Voyager is Voyager one, I
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  just looked it up. It is at a distance from the Sun in astronomical
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  units, which is one hundred and sixty three astronomical units. That's one hundred
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  and sixty three times the number of times the distance between the Earth and the
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  Sun. So that's one hundred and fifty million kilometers. Multiply that by one
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  hundred and sixty three and you will get what do you get? So I
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  was looking for eighty kilometers, but it's not there. I'll have to do
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  the numbers anyway, it doesn't matter. The main thing is its distance is
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  twenty two point five y five light hours away. That's how long it takes
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  the signal to get from Voyager to Earth. It's almost a day. It's
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  almost a light day away. So at that distance from the Sun one hundred
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  and sixty odd astronomical units, there's still significant light coming from the Sun.
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  Not to mention Venus and you know, Jupiter, the other planets, mostly
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  the Sun. Though you're being illuminated by the sun, so that's certainly opposite
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  as compared with just being illuminated by the starry sky, which is what I
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  was just talking about. So you'd see it really clearly. You wouldn't have
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  any problem making it out, assuming you I was dark adapted, so it's
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  fairly bright out there. We talked about the sensitivity of the human eye,
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  as you referred to how small amount of a light can we see as human
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  beings. I think there were some experiments let me think it one photon or
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  one yes, that's right. We might have talked about this. There were
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  experiments done that showed that the human eye is capable of detecting single photons.
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  It was under special circumstances, but that is just extraordinary when you think that
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  the human eye can also cope with broad daylight. That's the amazing thing about
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  the human eye. It can. You know, it's quite happy to see
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  light at one brightness and then a light that's only a million as bright if
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  I deal with that, and that's a combination of what's called retinal bleaching and
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  the iris of your eye opening and closing. It's all those things come together
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  to give you this unbelievably versatile and sensitive tool with which we can look at
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  the surroundings. Whether it's the rock face I'm looking at now, because that's
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  what about yea it consists of, or whether it's you know, the night
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  sky where you're looking at faint objects in the sky. It's quite amazing.
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  So even if you win deeper into space, way beyond our solar system,
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  you you would probably still see objects that you were near. There be enough
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  light from the stars. The Milky Way is bright. It would it would
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  you know, even if, as as Lee says, if even if you
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  were halfway between the Sun and Alpha Centauri, you'd still see it because of
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  the ambient light that's coming from from the stars. Yeah, and you'd still
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  see color because that's well, yeah, it's dark enough, it might turn
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  into the grays, which happened. Yeah, and I think that's likely.
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  I think I don't think you would see color. You would. You would
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  where it is now, there's enough light coming from the Sun that you'd see
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  color. But I think when you got further out you would start to just
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  see the you know, the as you said that that feed that's sort of
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  pale gray appearance where you look at very low low light levels, indeed where
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  the color cells aren't recept Mmm, they got LEI the answer of questions yes
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  to all of the above, basically question excellent question. All Right, let's
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  move on. This is from Fenton. Yeah, hello Fred and Andrew.
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  This is Fenter contacting from Saint Paul, Minnesota in the US. I sort
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  of have a different type of astrophysical question for you, and this is on
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  how to shield astronauts from radiation outside of the Van Allen I was curious if
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  you know of any pending technologies that would allow this of this choice would some
• 8:52
  people would say is lead? But I can think of several reasons why this
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  is not a good idea. How about a miniature down Allen Belt which could
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  surround a spacecraft? How does that sound? How could this become a reality?
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  Thank you very much. I hope you liked the question. I now
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  thanks vent and Venton always has these intriguing thoughts. I've noticed in the times
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  that we've heard from him. Maybe we should start by explaining what the Van
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  Allen Belt is. For those of us who just can't remember, like me,
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  it's sort the Van Allen Belt, so that basically the the you know,
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  the magnetic shielding around the Earth, which is caused by the magnetism of
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  the Earth. It's caused by the fact that we've got an iron core and
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  basically it's in two parts. It's solid and liquid, so it acts like
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  a dynamo. It's rotating, and that gives us this exactly the protection that
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  Fenton is talking about. I was going to refer I'm a bit annoyed.
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  Actually lost it. There is a very nice article on it's actually on the
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  BBC's website, their Sky at Night website. There's a lovely article on exactly
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  this here I found it. I hadn't lost it. How astronauts can hide
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  from radiational mars and it goes into the exactly the problem that Fenton's talking about.
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  How do you present how do you prevent astronauts basically becoming irradiated and over
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  time it's basically lethal because of the cosmic radiation that's coming down through space and
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  it does sell damage in your body and it can actually trigger cancer. So
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  the whole study of this is sorry, the thrust of this article BBC Sky
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  at Night Magazine is to discuss how you might protect astronauts from the radiation and
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  that's not just on Mars but en route. Okay, the solution that Fenton
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  has suggested is covered in a paragraph. I'm going to read it because we've
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  quoted where the sources for example. All right, let me go back up
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  with prograph. One method of helping astronauts to avoid the radiation on Mars is
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  active shielding. For example, superconducting electromagnets could be used to create a powerful
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  magnetic field to deflect the incoming charged radiation particles away, just as the Earth's
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  field does. That's the Lanele belt. The problem is that such solutions can
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  demand a lot of power to run, and the technology is a long way
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  from being fully developed. An easier alternative is passive shielding, simply placing a
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  thick bulk of shielding material between the crew habitat and the sky. And then
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  they go on to consider different materials. Aluminium aka aluminum, the metal that
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  spacecraft are constructed from, is actually a pretty bad radiation shield and they say,
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  when hit by an energetic cosmic ray, is atoms can shatter and fly
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  onwards to create even more radiation particles and Martian soil the regulith which if you're
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  on Mars, you might think about digging a hole there. It's got the
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  same problem, but it's actually abundant, and so you could use that to
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  dig a pole. If you put the two to three meter layer on top
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  of your habitat, then you'll get some protection. But the thing that surprised
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  me Andrew is once again it comes from this same article. Hydrogen is the
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  best shielding material as it's light atoms. Yeah, it's light atoms, and
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  by light I mean not heavy. Its light atoms don't create as much secondary
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  radiation, and so tanks of rocket fuel or water which is rich in hydrogen,
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  placed over crew quarters could double up as effective radiation shields. I've heard
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  that before that one way of protecting your spacecraft as it flies to Mars is
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  put it in a tank of water. It's the last thing you'd expect to
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  do, but water is a good childing material. And they also point out
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  the alternative of hydrogen rich plastics like polyethylene, could be used to cement regular
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  grains together this is on Mars and improve their shielding effect. So if you
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  want to read more about this, it's an article that originally appeared in the
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  August twenty two issue of BBC Sky at Night magazine and it covers pretty well
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  amost the ideas that have been that have been suggested for this radiation issue.
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  It's one that's got to you know, it's going to find an answer soon
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  because put all, Elon and his starship is getting nearer to thinking about going
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  to Mars. I don't think it's ever going to happen, but that's uh,
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  that's something he'll definitely be thinking about. Yes, indeed, he's too
• 14:24
  busy dealing with the Australian government at the moment. Indeed, that's right,
• 14:28
  some of the content on Twitter that the government wants to get rid of simply
• 14:31
  because of its volatility. But anyway, that's a different story. But there's
• 14:35
  plenty of water on Mars, so maybe maybe creating those water barriers is probably
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  the simplest thing to do. You've already got the material there, if you've
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  if you've landed in the right spot where you've got whatever, that's the question.
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  Yes, indeed, well done, Fent, and you actually happened across
• 14:52
  some of the answers to in asking your question. Uh, this is based
• 14:58
  out's Andrew and here with Professor Fred Watson. Three four space nuts. Now
• 15:09
  Fred our next question comes from Robert. Hi, guys, love your show.
• 15:13
  Sorry for the long question, but feel free to paraphrase or shorten it.
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  Our moon is heavily created and has given us a lot of insight into
• 15:22
  the history of the Solar System and perhaps how the planet's formed. But what
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  if we had a moon like the icy moon Europa or the shrouded in Hayes
• 15:31
  Titan, both of which don't show immediate evidence of cratering. Would our theory
• 15:37
  about how the planets developed would be different? What other insights about our Solar
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  System would be missing or would we be missing? And lastly, would we
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  have spent or would we have sent people to land on such moons? I
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  e? Would they be more dangerous for astronauts? Cheers Robert in Vienna,
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  Austria. Wow, I don't think we've had a question from Vienna before,
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  have we? Lovely to hear from you, Robert. I think I think
• 16:07
  Robert might have been in touch once before. It's here from Vienna. Yeah,
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  I was in Vienna at the beginning of last year and I think I
• 16:15
  think we got something around about the same time. And I was at the
• 16:21
  u ND when I was the copyhoss beating Anyway, that's another issue. What
• 16:26
  if we had Yeah, it's a really interesting question. What would we not
• 16:33
  know about the Solar System if our moon was basically one that had been resurfaced
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  in recent years, Because that's what makes us surface smooth. That's how we
• 16:48
  recognize the fact that the universe sorry that the It's how we recognize the age
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  of a surface is by how many creators it's got the oldest, the older
• 17:00
  the surface, the more craters it has. And so the moon's south southern
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  region, which is heavily created, as is the backside, tell us that
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  early on in the Solar System's history it was very wild and wily place,
• 17:14
  with things charging about all over and causing these craters. Now, if we
• 17:18
  had a moon that was like Europa that had you know, I see guysers
• 17:23
  on it, that basically covered up the craters, would we have known about
• 17:26
  that? My guess is yes we would, because we'd see other bodies within
• 17:33
  the Solar System, like you know, other moons, like places like Series,
• 17:41
  the biggest of the asteroids, the dwarf planet that dominates the asteroid belt,
• 17:45
  that's heavily created. Parts of Pluto are heavily created Mi Mas one of
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  Saturn's moon. His moons is heavily created too, so we'd know about it
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  by looking at other objects, even if our own moon was smoothly surfaced.
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  It's but the Roberts last point on this, would we have sent people to
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  land on such a moon? I think I don't know. That's a really
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  good question. I mean, we have sent people to land on our moon
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  as it stands, with an ancient surface. In fact, where they landed
• 18:23
  were more recent than the heavily created surfaces, because there were, principally in
• 18:29
  the Maria the basalt planes. So maybe that suggests that we would have landed
• 18:37
  people on Europa as well, because I think we probably, Yeah, we
• 18:41
  probably would because it would have a solid surface, there'd be places, because
• 18:45
  it would be so close to us, we'd be able to examine and find
• 18:48
  the right landing points. Might be a bit more difficult with a moon that
• 18:53
  shrouded in gas. Yeah, yeah, that's right, and especially a place
• 19:00
  like Tyson. I still think we'd have done it. Actually, I think,
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  you know, the JFKs promised to put past lots on the moon would
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  have still held good even if it had been a very different place. If
• 19:15
  it had been like EO. It might have been a different story where you
• 19:19
  know you've got the most volcanically active body in the entire Solar system with stuff
• 19:25
  going off all over the place. I think we might have been a bit
• 19:26
  more reluctant to land on EO. Yes, possibly, so it would be
• 19:33
  interesting to have something different. But then if we'd always if we'd always had
• 19:37
  an ice moon, we probably would have caught a question from Robert asking if
• 19:41
  we had a rocky moon. Now would interpretation of the formattage and planets if
• 19:49
  there was a rocky moon next us instead of an im Yes, in an
• 19:53
  alternative universe, Robert, you would have flipped your question. But to hear
• 19:57
  from you, hope it all is well in Austria. Our final question for
• 20:02
  this episode comes from Duncan. Hello, Duncan here from Weymouth in the UK.
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  Again, of course just looking, was just doing some reading and I
• 20:15
  noticed that Uranus and Neptune are often referred to as ice giants. Now,
• 20:23
  given that ice is basically just sort of like a rock form of water or
• 20:32
  CO two or whatever else, but basically just the solid form of it,
• 20:37
  why are they not just called rock giants? Why do we make the definition
• 20:42
  of ice rather than just calling them rock It just seems odd because the little
• 20:48
  planets in the Inner Solar System are referred to as rocky planets, So given
• 20:55
  that they're also apparently rocky, why are they not called rocky giants? Okay,
• 21:02
  thank you boy, thanks. Duncan appreciate your questions as always. Yeah,
• 21:07
  why do we call them ice giants just for the sake of the exercise,
• 21:11
  because there's gas giants and ice giants, Yeah, except one is a
• 21:17
  subset of the other. And so all four of the outer planets Jupiter,
• 21:22
  Saturn, Neptune, sorry, Uranus and Neptune, they're all gas giants because
• 21:26
  they have high mass, you know, much more in the case of Jupiter,
• 21:34
  certainly than our own planet. They've got the giants that big, they've
• 21:41
  got high mass, and they don't have a visible surface, which is why
• 21:48
  they call gas giants, because all we see is a gassy envelope. Just
• 21:52
  to go to the last of Duncans questions there, we wouldn't call the inner
• 21:57
  planet's rocky giants because not giants. They're kind of normal planet size. You
• 22:02
  know. If you think of the Earth as being your standard planet, then
• 22:07
  Mercury Venus and Mars are similar in size, all smaller venuses about the same
• 22:12
  size, but Mercury and Mars, of course are smaller. So it's only
• 22:17
  when you compare with the size of Earth that you'd start talking about giants because
• 22:22
  they are much much bigger than Earth. And so that's the gas giants.
• 22:26
  So why are Urinous and Neptune called ice giants? Horse They have hazes of
• 22:33
  ice in their atmosphere. So, and that's the trick. It's not a
• 22:40
  solid surface, it's not rock. It's a haze. It's kind of like
• 22:44
  a dust of ice which permeates their atmosphere, and it's water ice in fact,
• 22:51
  mostly So that's why they called ice giants, because unlike Saturn and Jupiter,
• 22:57
  which don't have these hazes, the outer the rocky rocky sorry, the
• 23:03
  two outer planets Uranus and Neptune do they have ice hazes in their atmosphere,
• 23:07
  hence the name. Okay, because the last episode we learned there wasn't much
• 23:14
  water in Jupiter. That's right, in the two outer I guess giants.
• 23:21
  Yeah, it sounds like there is. Is that why they're a different color?
• 23:23
  Yes, yes, I think that's right there. And also their atmospheric
• 23:29
  constituents are different. They don't have the same belt structure that Saturn and Jupiter
• 23:33
  do. It may be that that's because any belts that exist are much lower
• 23:38
  in the atmosphere and so you don't see them. Yeah. I mean there's
• 23:42
  there's a strong body of advocacy within the space fraternity to get get more spacecraft
• 23:55
  out to Uranus and Neptune, because they're the two planets about which we know
• 24:00
  least and it will be good to know more. Yeah. Well, if
• 24:06
  you sit down in snow for long enough, your rainus turns into our ice.
• 24:11
  I couldn't help it. Sorry, Yeah, which is why we call
• 24:17
  it Urinus. Yeah, it's just a joke. You've got to tell you
• 24:23
  to Yes, I blame Johannes Border, who is the person who chose the
• 24:30
  name. It's fine in German. Is nothing wrong than ruins, all the
• 24:37
  jokes, all right. So, yes, they're ice giants for a very
• 24:41
  good reason, Duncan, because they've got ice in them in the atmosphere.
• 24:45
  But technically speaking, they are in fact gas giants. But yes, differentiate
• 24:49
  them because of their substantially different atmospheres. There you are, thanks Duncan.
• 24:55
  Great to hear from you. Great to hear from everybody. Thanks for sending
• 24:57
  in your questions. Don't forget. You can see in questions via our website,
• 25:00
  spacenuts podcast dot com, space nuts dot io, and all you have
• 25:04
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• 25:08
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  button below, which, yes, it's down there somewhere I don't know,
• 25:33
  one of those places. Fred has always Thank you so much, pleasure and
• 25:37
  you see you, Sue. Okay, Fred Wat's an astronomer at large.
• 25:41
  We'll catch him on the next episode of Space Nuts. We might catch you
• 25:45
  then as well, because not to you today, didn't even call in sick.
• 25:51
  I need a note and from me Andrew dot Thanks very much for your
• 25:53
  company. We'll see you again soon on the next episode of Space Nuts.
• 25:57
  Bye bye. You'll be listening to the Space Narts podcast available at Apple Podcasts,
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