Latest / Space News Today / Cosmic Questions: Time, Mass, and the Spectacle of Auroras | Space Nuts: Astronomy Insights &...

Transcript

Cosmic Questions: Time, Mass, and the Spectacle of Auroras | Space Nuts: Astronomy Insights &... · Space News Today

• 0:00
  Hi there. Thanks for joining us again.
• 0:02
  This is Space Nuts, a Q&A edition. My
• 0:04
  name is Andrew Dunley. Hope you're well.
• 0:07
  Stick around. We have got questions from
• 0:10
  uh our audience. Uh one about time in
• 0:13
  anti-gravity and the speed of time. Uh
• 0:17
  that's always fun to talk about. Uh
• 0:21
  we've got another question about
• 0:22
  supernova remnants. uh the colors of
• 0:26
  Aurora and uh a light speed boost idea.
• 0:30
  This is a could I would I should I type
• 0:33
  of with my spaceship do something that
• 0:35
  might give me a light speed boost. We'll
• 0:38
  see if it works on this edition of Space
• 0:41
  Nuts.
• 0:42
  >> 15 seconds. Guidance is internal. 10 9
• 0:47
  ignition sequence start.
• 0:48
  >> Space nuts. 5 4 3 2
• 0:52
  >> 1 2 3 4 5 5 4 3 2 1
• 0:54
  >> space notice
• 0:55
  >> astronauts reported feels good.
• 0:58
  >> And he's back uh once again to try and
• 1:01
  solve all your little riddles. Here's
• 1:03
  Professor Fred Watson, astronomer at
• 1:04
  large. Hello, Fred.
• 1:06
  >> Uh hello there, Andrew. It's very good
• 1:09
  to be talking with you. It is. I'm sorry
• 1:11
  I've turned into an Irishman cuz I
• 1:13
  >> I wonder what was happening there.
• 1:15
  >> Yeah, in my trip to Ireland, which is
• 1:17
  great. There's nothing wrong with the
• 1:19
  Irish when we were there in would have
• 1:21
  been July. Yeah, July. Uh they really
• 1:25
  bunged it on for us at um at a place
• 1:28
  called Cove. It used to be called um I
• 1:32
  think Victoria. Was that what it was
• 1:34
  called? Um no no. Uh anyway, that it's
• 1:38
  where the uh uh Titanic made its last
• 1:41
  stop before getting out to the Atlantic
• 1:43
  and picked up its last groups of
• 1:45
  passengers and some very sad stories
• 1:48
  >> as well. Uh yeah, the the pier where
• 1:50
  everybody got on board the the um the
• 1:53
  boats to go out to the Titanic cuz it
• 1:55
  couldn't actually anchor at at Paul had
• 1:58
  to anchor outside the the harbor at u
• 2:01
  >> at Cove. Um it um it's still there parts
• 2:07
  of it.
• 2:07
  >> H so you can still see the remnants of
• 2:10
  that old um and and the White Starline
• 2:13
  office is still there as well which is
• 2:15
  now a museum where you can learn about
• 2:18
  the Titanic through the Titanic
• 2:19
  experience. I highly recommend that in
• 2:22
  the town of Cove which is near County
• 2:24
  Cork. County Cork it is. Yeah. Uh lovely
• 2:28
  place and they they had Australian and
• 2:30
  New Zealand flags everywhere and music
• 2:32
  playing and they know how to party those
• 2:35
  people. Yeah. Terrific. Uh shall we um
• 2:38
  do some questions, Fred?
• 2:41
  >> No, no, I think we should just have a
• 2:43
  cup of tea.
• 2:44
  >> Yeah, we that we'd probably have less
• 2:46
  trouble. Uh let's firstly get a question
• 2:49
  from Andy.
• 2:51
  >> Hi guys, it's Andy here from the UK.
• 2:54
  First time questioner. two questions
• 2:57
  both time related. Um the first question
• 3:04
  um as mass and gravity are so closely
• 3:08
  related and the higher a mass is the
• 3:12
  slower time will flow.
• 3:16
  What would happen to the flow of time in
• 3:18
  an anti-gravity field? So that's the
• 3:21
  first question. Um the second question,
• 3:26
  if a planet had life that was
• 3:30
  intelligent and was evolving and had the
• 3:34
  potential to become space fairing, but
• 3:38
  the planet was high gravity. Is the
• 3:42
  playoff between gravity and the speed of
• 3:45
  time enough that that will make a
• 3:48
  significant difference to the evolution
• 3:51
  of the planet on galactic scales? Hope
• 3:54
  that one makes sense. Great program. No
• 3:56
  doubt I'll be back again.
• 3:58
  >> Wow, Andy, where gee whiz, you've been
• 4:00
  pondering that for a while. There's some
• 4:02
  great questions there. We'll um we'll
• 4:04
  tackle the first one first, unless you
• 4:05
  want to do the first one second and the
• 4:07
  second. No, I don't know. uh time, the
• 4:09
  effect of um uh the effect on time
• 4:13
  um if it passes through an anti-gravity
• 4:16
  field or just the effect on time in an
• 4:18
  anti-gravity field.
• 4:21
  Yes. So um so Andy's right actually uh
• 4:25
  if you so what you've got is this
• 4:28
  phenomenon called time dilation. Appears
• 4:30
  that clocks slow down when you're in a
• 4:33
  gravitational field. um they only appear
• 4:36
  to be slowed down to outside observers.
• 4:40
  To you as the person in the gravity
• 4:42
  field, it makes no difference. The
• 4:43
  clock's just ticking at the same speed
• 4:44
  as it always did. But to an outside
• 4:47
  observer, your clocks are ticking more
• 4:48
  slowly. uh if there was such a thing as
• 4:51
  an anti-gravity field, and we have no
• 4:54
  knowledge of anything like that at the
• 4:56
  moment, although people have worked very
• 4:58
  hard to try and demonstrate
• 4:59
  anti-gravity,
• 5:01
  uh as you can imagine, it would be a
• 5:02
  very useful thing to be able to harness.
• 5:05
  Um uh if if you could have anti-gravity,
• 5:08
  in other words, something that um uh
• 5:12
  actually repelled rather than attracted.
• 5:14
  Yes. The the um or or at least No, let
• 5:18
  me put it another way. It's not repel
• 5:19
  repulsion. It's reducing the effect of
• 5:22
  gravity. I think anti-gravity might
• 5:25
  might reduce the effect of gravity.
• 5:28
  >> And it could if you reduce it beyond
• 5:29
  zero, it could produce a repulsion. But
• 5:32
  that is not that doesn't really matter
• 5:35
  for this argument because what happens
• 5:37
  is um yes, relativity says that time
• 5:40
  would actually speed up. uh time as I
• 5:43
  said to the person in the anti-gravity
• 5:45
  field would keep on ticking away as
• 5:47
  normal but to the outside observer uh
• 5:49
  the time would appear to be passing more
• 5:51
  quickly.
• 5:52
  >> Isn't it the same effect if you're
• 5:53
  falling into a black hole? What you're
• 5:56
  seeing is happening in real time because
• 5:58
  you're living your life like you do
• 6:00
  anywhere, but to the observer
• 6:04
  you would be,
• 6:06
  >> you know, completely different bucket of
• 6:08
  fish.
• 6:09
  >> That's right. Time slows down. You're
• 6:12
  everything appears more slowly and when
• 6:14
  you cross the event horizon you're sort
• 6:15
  of frozen on it.
• 6:17
  >> Yeah. Which means that
• 6:18
  >> weird, isn't it? Event horizons are
• 6:19
  always all splattered with things that
• 6:22
  are falling into the maybe.
• 6:24
  >> Yeah.
• 6:25
  >> Hard to imagine. It's like the front of
• 6:27
  a car.
• 6:28
  >> Well, in summer white hot. Yes.
• 6:32
  >> Um Yep. I think this was portrayed quite
• 6:35
  well in the movie Interstellar where
• 6:37
  they had to go down onto a planet that
• 6:39
  was under the effect of a a black hole
• 6:41
  and every hour on the planet surface
• 6:44
  equated to 7 years back on the
• 6:46
  spaceship. Um they they did portray that
• 6:50
  quite well,
• 6:52
  that effect.
• 6:53
  >> Yeah.
• 6:54
  >> Okay. So, there's no such thing really
• 6:56
  as an anti-gravity field, but um he he'd
• 6:59
  be right. The effect would be
• 7:01
  >> Yeah, that's right. But the second part
• 7:03
  of Andy's question,
• 7:05
  >> yes, high levels of gravity and its
• 7:08
  effect on the speed of time.
• 7:10
  >> Well, what he's saying is if you had a a
• 7:13
  planet
• 7:14
  >> or if you had if you had a civilization
• 7:17
  working in a very high gravitational
• 7:19
  field.
• 7:19
  >> Yeah.
• 7:20
  >> Uh would that mean that they would
• 7:22
  evolve more quickly and things would
• 7:23
  develop more quickly?
• 7:25
  >> Um and I suppose the answer is yes, but
• 7:27
  only to an outside observer. uh to to
• 7:30
  the people doing it, it would be just
• 7:32
  the same. Um so yes, maybe if our planet
• 7:36
  had a hugely different gravitational
• 7:39
  field from what it does have. Uh seen
• 7:42
  from the outside, we might look as
• 7:43
  though we're evolving more quickly and
• 7:45
  developing technology more quickly. But
• 7:48
  to the to to us, it would be just the
• 7:50
  same as if we had, you know, a lower
• 7:52
  gravitational field. It
• 7:55
  >> this would complicate the search for
• 7:57
  intelligent life, wouldn't it? Uh I mean
• 7:59
  you might find a a planet um and go hey
• 8:02
  something's going on there. Um but it's
• 8:05
  in it's in a you know high gravity
• 8:08
  environment and um maybe it was
• 8:11
  happening
• 8:13
  some time ago but it's all over Red
• 8:15
  Rover. I mean I don't know. It's it's a
• 8:18
  headscratcher.
• 8:20
  Or here's one. If you do find a
• 8:23
  civilization living in a in a on a
• 8:26
  planet and you land to say hello and
• 8:28
  then you take off again and find out
• 8:30
  that everyone at home's dead because
• 8:31
  you've been gone 500 years but you were
• 8:33
  only gone a week.
• 8:35
  >> Yeah. Well, there's that too. That's
• 8:37
  right.
• 8:38
  >> Yeah. That's um special relativity.
• 8:41
  That's the one
• 8:42
  >> the relativistic difference in time
• 8:44
  because you're traveling at speeds near
• 8:46
  the speed of light.
• 8:47
  >> Yeah. I mean it happens happens on
• 8:49
  Earth. They've done those tests with um
• 8:52
  highly sensitive clocks and and tested
• 8:54
  them at different altitudes and you know
• 8:57
  they they've come back and went well
• 8:59
  look there's a thousandth of a second
• 9:00
  difference in their performance. So you
• 9:03
  know that we we moved through time. I
• 9:05
  read a story the other day Fred which I
• 9:07
  wish I'd kept it. um about a cosmonort,
• 9:11
  I think it was, who'd spent so much time
• 9:13
  in space that they estimated that he was
• 9:17
  um he was actually slightly ahead of
• 9:20
  time than everybody else,
• 9:23
  and I can't remember the details, but uh
• 9:25
  it was really fascinating. Um I they've
• 9:29
  done a they've released a paper about
• 9:31
  it. I'll see if I can find it.
• 9:33
  >> Interesting.
• 9:34
  >> I might do that while while you answer
• 9:36
  this next question. Thank you, Andy. I
• 9:38
  love that idea though. Um, keep them
• 9:40
  coming.
• 9:41
  >> Now, let's take a break from the show to
• 9:43
  tell you about our sponsor, NordVPN.
• 9:46
  Now, I think we'll all agree that
• 9:47
  exploring the universe is thrilling, but
• 9:50
  exploring the internet without
• 9:52
  protection, that's a black hole you
• 9:54
  don't want to fall into. Sorry. Uh, as a
• 9:57
  Space Nuts listener, we have an
• 9:59
  exclusive deal for you so you can stay
• 10:01
  protected. And that is NordVPN. It's the
• 10:05
  fastest, most secure way to browse the
• 10:07
  web. With NordVPN, you get next level
• 10:11
  encryption,
• 10:13
  blazingly fast servers around the world,
• 10:15
  and zero tracking, so you can stream,
• 10:18
  shop, or scroll safely. Uh, it's the
• 10:22
  tool I personally trust when we're
• 10:25
  diving into the internet. And um, we
• 10:27
  want to give you peace of mind. Uh, I've
• 10:30
  used it overseas several times. I've
• 10:32
  used it at home. It works and it is
• 10:35
  seamless. Uh, head to
• 10:37
  nordvpn.com/spacenuts
• 10:40
  for an exclusive deal just for Spacenuts
• 10:42
  listeners. Big savings plus 4 months
• 10:46
  extra absolutely free. Don't surf the
• 10:49
  cosmos unshielded. Uh, secure your
• 10:52
  digital universe today with
• 10:54
  nordvpn.com/spacenuts.
• 10:57
  And don't forget their 30-day money back
• 10:59
  guarantee. Go to nordvpn.com/spacenuts.
• 11:06
  >> 3 2 1
• 11:09
  >> Spacenuts.
• 11:11
  Uh, this question comes from Mark. Hi
• 11:14
  Andrew and Fred and team. My name is
• 11:16
  Mark Turner and I live in the south of
• 11:18
  England. I'm sorry about that. About
• 11:20
  five about five minutes from Patrick
• 11:22
  Moore's house as a point of interest.
• 11:25
  Wow. Um, I've been listening now for
• 11:28
  just over three years and always look
• 11:30
  forward to Thursday lunchtime when I sit
• 11:32
  down and listen to you guys. Sorry, we
• 11:34
  were talking about toilet stuff earlier.
• 11:35
  I hope that didn't mess you up. Uh, my
• 11:38
  question is, it's generally accepted
• 11:40
  that all of the heavy elements were
• 11:42
  produced in an even larger star than
• 11:45
  ours that went supernova, which leads me
• 11:48
  to uh to this. Can we still see the
• 11:51
  remains of the star that made us in the
• 11:54
  night sky? Or do we know uh at what
• 11:57
  point in the night sky the star would
• 11:59
  have been by turning back the cosmic
• 12:02
  time clock? Keep up the great work,
• 12:04
  Mark.
• 12:06
  >> What do you reckon about that one?
• 12:08
  >> Um so the answer is no. Um because
• 12:13
  the so yes um uh the what we call the
• 12:18
  interstellar medium the gas between the
• 12:20
  stars is enriched in its chemical
• 12:24
  um abundance. The amount of heavier
• 12:27
  elements that are in it is enriched over
• 12:29
  time because of supernova explosions.
• 12:32
  stars that have that have detonated and
• 12:35
  gone through this high temperature
• 12:37
  process where you get heavier elements
• 12:39
  created and some of the some of the
• 12:41
  heavy elements are we now know are
• 12:43
  created in neutron star collisions. Um
• 12:46
  but that doesn't matter which which it
• 12:49
  is. The bottom line is that it's the
• 12:53
  general interstellar medium that is
• 12:55
  enriched. So you've got an explosion
• 12:57
  that takes place and over millions of
• 13:00
  years the debris from that explosion
• 13:03
  just gets absorbed into the clouds of
• 13:06
  gas and dust that are then going to form
• 13:08
  uh later generations of stars. So
• 13:12
  there's really no way that the remnants
• 13:15
  of the star that gave us uh the uh the
• 13:19
  you know the heavier elements um there's
• 13:22
  no way that we can pinpoint that. It it
• 13:26
  may be that some of the supernova
• 13:29
  remnants that we see and we see many
• 13:31
  around the sky that some of those were
• 13:35
  responsible for some of the stuff
• 13:40
  they were probably responsible for
• 13:42
  enriching the interstellar medium closer
• 13:45
  to them than we are. That's kind of the
• 13:47
  point I I guess I want to make. the the
• 13:50
  debris that gave us our enriched
• 13:52
  interstellar medium is probably long
• 13:55
  dissipated and we could not identify it
• 13:59
  with any of the known supernova remnants
• 14:01
  because they are they're still enriching
• 14:04
  their local environment if I can put it
• 14:06
  that way because they're still intact
• 14:08
  structures. They're expanding and
• 14:10
  dissipating but we see them as intact
• 14:12
  structures. And so the the debris that
• 14:15
  made us 4.6 six billion years ago is uh
• 14:20
  basically is not is nowhere near you
• 14:22
  know it's not nothing to do with them.
• 14:25
  Um and partly because those explosions
• 14:27
  took place more recently than the 4.6
• 14:29
  billion years ago origin of our own
• 14:32
  solar system.
• 14:33
  So uh the
• 14:37
  basically uh yes the the answer is no.
• 14:40
  We can't we can't identify those
• 14:43
  remains. uh and turning back the cosmic
• 14:45
  time clock. We can do that but but we
• 14:48
  can't do it in the sort of detail. I
• 14:49
  mean we can do it in a physical phys
• 14:51
  physical modeling sense. We're not
• 14:53
  looking at anything unless we're looking
• 14:55
  at things at great distances where we
• 14:57
  are looking back in time. Uh but for the
• 15:00
  the physics that you we use to model the
• 15:02
  universe um we we can't wind back the
• 15:06
  clock in enough detail to see where
• 15:09
  these objects exploded. uh they may be
• 15:12
  you know many many thousands of tens of
• 15:14
  thousands of light years away uh from
• 15:16
  where we are now. Uh all they did was
• 15:19
  enrich the medium around them and that's
• 15:20
  where we found our own uh solar system
• 15:23
  being formed. So we can't we can't look
• 15:26
  back in time in that regard.
• 15:28
  >> Okay. Thank you Mark. Uh by the way I
• 15:31
  was a pretty regular visitor to Patrick
• 15:33
  Moore while he was still alive. So I
• 15:35
  know that house well at Celi it was
• 15:37
  called Farings. uh is a lovely house
• 15:40
  actually uh and um when I used to visit
• 15:43
  him he was always very welcoming uh and
• 15:46
  um always glad to show me around.
• 15:48
  >> Wonderful. Wow. Lucky you. Yeah.
• 15:51
  >> Yeah.
• 15:51
  >> Now um just to sort of draw on Mark's
• 15:55
  question um so he's right about a
• 15:58
  supernova creating the heavy elements.
• 16:00
  >> Yes.
• 16:01
  >> So how do they end up being a part of
• 16:04
  our planet? Is is that because the
• 16:06
  supernovas created the the the spawning
• 16:09
  ground or being you know run through it?
• 16:13
  What how does that work?
• 16:14
  >> Yeah, I mean it's what I was saying
• 16:16
  basically the you know you get a
• 16:18
  supernova explosion which um sends shock
• 16:22
  waves out. Uh it sends enriched gas out
• 16:26
  and that gas gradually diffuses into the
• 16:30
  background
• 16:31
  uh what we call the interstellar medium.
• 16:34
  the the gas between the stars. It's very
• 16:36
  very rarified, but that's where that
• 16:39
  stuff ends up. And as you then get
• 16:41
  concentrations of that gas into clouds
• 16:44
  of hydrogen, mostly hydrogen, but other
• 16:47
  elements as well because it's been
• 16:48
  enriched, then that is what would form
• 16:51
  the next solar system. uh and so that
• 16:54
  you know that gradual process of uh
• 16:58
  stars forming exploding enriching the uh
• 17:01
  interstellar medium then interstellar
• 17:04
  medium creates other star systems which
• 17:07
  do the same thing. It's why as the
• 17:09
  universe ages, you're going to get an
• 17:11
  enrichment of the number of of heavy of,
• 17:14
  you know, quantities of heavier elements
• 17:16
  that there are within the universe. And
• 17:18
  that's actually one way that we can
• 17:20
  measure the ages of stars by how much of
• 17:22
  this stuff they've got in them. Because
• 17:24
  when they were formed, the universe
• 17:26
  would have been at a certain point of
• 17:27
  enrichment.
• 17:29
  uh and you know that for that point is
• 17:32
  fossilized if I can put it that way in
• 17:34
  the star itself by the chemical
• 17:37
  composition that it demonstrates.
• 17:39
  >> Okay, very good. Um it's it's a law of
• 17:42
  diminishing returns though, isn't it?
• 17:44
  Eventually all of this is going to stop
• 17:46
  happening.
• 17:46
  >> Yes, that's right. Eventually the
• 17:48
  universe will die because of that
• 17:50
  because there won't be any more any
• 17:52
  there won't be any gas in which to
• 17:54
  create supernova explosions which is the
• 17:56
  raw material of stars. intelligen gas
• 17:58
  that will all be used up eventually
• 18:00
  >> and we'll have what used to be called
• 18:02
  the heat death of the universe unless it
• 18:05
  starts collapsing on itself with you.
• 18:07
  >> Well, yeah. I mean there's there's all
• 18:08
  these terrible perilous things that are
• 18:11
  going to happen but um
• 18:14
  you know it's not going to happen next
• 18:15
  week. The week after maybe cuz we're on
• 18:17
  holidays
• 18:18
  >> if we're lucky or the week after. Yeah,
• 18:19
  that's right.
• 18:21
  >> Yeah. Uh thank you Mark. Great question.
• 18:23
  Uh, now that thing I was trying to look
• 18:25
  up, I can't find the exact story, but um
• 18:28
  I I found something that that kind of
• 18:30
  explains the concept. Um, apparently for
• 18:33
  a six-month mission on the International
• 18:35
  Space Station, an astronaut ages 0.005
• 18:39
  seconds less than they would on Earth.
• 18:42
  So, this this particular um cosmonort
• 18:46
  that I'm talking about apparently has
• 18:47
  spent so much time in space that he's
• 18:50
  actually I think it's 222
• 18:54
  um minutes younger than he
• 18:58
  >> would had he not gone into space.
• 19:01
  >> It's like seconds rather than minutes.
• 19:03
  Yeah.
• 19:03
  >> Oh, 222 seconds. Yes, exactly.
• 19:06
  >> Yeah. Um so I I Yeah, I read it last
• 19:10
  week. I meant to send it to you and I
• 19:11
  completely forgot. So, uh, but that's
• 19:13
  the that's the the the guts of the
• 19:15
  story. Uh, this is Space Nuts. Andrew
• 19:18
  Dunley with Professor Fred Watson.
• 19:21
  >> Space Nuts.
• 19:23
  >> Uh, we have a question from one of our
• 19:26
  regular contributors. This is Casey.
• 19:29
  >> Hi guys, this is Casey from Colorado.
• 19:31
  Um, I just saw Red Northern Lights and
• 19:34
  it was it was really incredible. Um, I
• 19:37
  was hoping that you could please explain
• 19:39
  why auroras come in different colors. I
• 19:41
  hope we're both well and thanks for the
• 19:43
  podcast.
• 19:44
  >> Uh, thank you, Casey. Casey sent in a
• 19:46
  few um questions in recent times and
• 19:49
  we're more than happy to answer. She
• 19:50
  comes up with some interesting ideas.
• 19:52
  Uh, I just thought this was a good
• 19:54
  question to answer. Uh, and I know we've
• 19:56
  talked about it before, but there's been
• 19:58
  some great auroral activity of late.
• 20:01
  >> And even in parts of Australia where you
• 20:05
  just don't see them, they have been
• 20:07
  absolutely stunning. Even as recently as
• 20:09
  a week or two ago, we had some fabulous
• 20:11
  photographs coming out of uh many, many
• 20:14
  parts of southeastern Australia. And um
• 20:18
  you know it prompted a thought in my
• 20:20
  mind that the one the aurora we see here
• 20:24
  generally are pink but when you see
• 20:28
  photos up in the northern hemisphere and
• 20:30
  when you're practically underneath them
• 20:31
  they're green. Uh and and I'm sure the
• 20:34
  colors can vary into many areas. Fred u
• 20:40
  I mean you've you've taken tours on
• 20:41
  these um to see these things. You've
• 20:43
  you've seen that like this is boring for
• 20:45
  you.
• 20:46
  Uh
• 20:47
  >> it's never boring actually. I didn't
• 20:49
  imagine it would be just always
• 20:51
  spectacular. But you're absolutely
• 20:53
  right. So when we're up in uh uh Ala,
• 20:57
  which is far northern Norway, or um
• 21:00
  Kirina, which is far northern Sweden, or
• 21:02
  Aiscoco, which is also far northern
• 21:04
  Sweden, and looking at the aurora,
• 21:06
  you're basically standing underneath it.
• 21:09
  And so you see the aurora as it really
• 21:11
  is. Uh, and it you've got lots of colors
• 21:15
  in it. Um, but the the pink and red Aori
• 21:20
  are typically seen when you're a long
• 21:24
  way from the action. Uh, and the green
• 21:27
  the bottom line is the the green is
• 21:29
  talking shift.
• 21:31
  >> No,
• 21:31
  >> no, no, but we're talking atmospheric.
• 21:34
  >> We're talking uh we're talking um
• 21:37
  emission line spectroscopy.
• 21:38
  >> Oh, okay. Well, I never would have
• 21:40
  thought of that.
• 21:41
  >> Yeah. So, um, so the the pink and red
• 21:45
  aurori, uh, you'd see them if you're in
• 21:47
  the northern hemisphere, you'd see them
• 21:49
  on the northern horizon. In the southern
• 21:50
  hemisphere here in Tasmania, you see
• 21:52
  them very often down in the south.
• 21:54
  Usually, the green part is below the
• 21:56
  horizon. It's, you know, it's too far
• 21:59
  over the Earth's curvature to see, and
• 22:01
  that's why you only see the red and
• 22:03
  that's a clue to what's happening here.
• 22:06
  So, um, what you've got is the
• 22:09
  atmosphere, uh, being excited by
• 22:12
  radiation from the sun. These, uh, these
• 22:16
  subatomic particles charge out from the
• 22:19
  sun. If you've got a solar flare or
• 22:20
  something like that, they going at
• 22:22
  typically a million kilometers an hour.
• 22:25
  Uh so they take a couple of days to get
• 22:27
  here and then they're sort of funneled
• 22:29
  down the earth's magnetic field lines u
• 22:32
  and they're most concentrated near the
• 22:34
  magnetic poles which is why it's around
• 22:36
  the magnetic poles that you see most
• 22:38
  aurori. This is a sort of simplified
• 22:40
  version of the story, but um what
• 22:42
  happens is they these electrons and you
• 22:45
  know they're accelerated. They're quite
• 22:46
  high energy. They hit atoms of oxygen
• 22:51
  and nitrogen in the earth's atmosphere
• 22:53
  and they make them glow. And the car the
• 22:56
  important thing here is that those atoms
• 23:00
  of oxygen and nitrogen actually they're
• 23:02
  molecules as well. uh O2 which is a pair
• 23:05
  of oxygen atoms or N2 which is a pair of
• 23:07
  nitrogen atoms. Um they behave
• 23:10
  differently at different pressures and
• 23:12
  of course as you go up through the
• 23:14
  atmosphere the pressure gets steadily
• 23:16
  lower. So the most common one is the
• 23:19
  green light and that's uh when you've
• 23:22
  got oxygen being excited to emit this
• 23:26
  green color. It's what we call a
• 23:28
  spectrum line. It's a particular
• 23:29
  wavelength which means it's a particular
• 23:31
  color. Uh but it's green. Uh and that uh
• 23:35
  works for pressures that you see between
• 23:38
  about 100 and 200 kilometers above the
• 23:41
  earth's atmosphere.
• 23:43
  Above 200 kilometers, the pressure is
• 23:47
  lower uh and the green line doesn't form
• 23:50
  or the green light is not formed. uh
• 23:52
  it's actually quenched and there is a
• 23:55
  different atomic process that gives rise
• 23:58
  to red light uh 630 nanometers if I
• 24:02
  remember rightly is the is the
• 24:04
  wavelength so you get this red light
• 24:06
  which is still oxygen but it's oxygen at
• 24:09
  a lower pressure than what comes out
• 24:11
  from the green so between 1 and 200
• 24:14
  kilometers you're going to see green
• 24:15
  aori above that you're going to see red
• 24:17
  aurori and that's why we only see the
• 24:20
  red ones if you're looking from
• 24:21
  Australia because the green is way below
• 24:23
  the horizon. Um if you've got a really u
• 24:27
  powerful stream of subatomic particles
• 24:31
  then they will penetrate below 100
• 24:33
  kilometers and that then excites uh not
• 24:37
  the oxygen but the nitrogen. You get um
• 24:40
  what's called molecular exitation.
• 24:42
  Nitrogen molecules start emitting light
• 24:44
  and they emit in several different
• 24:46
  colors like per um deep blue. Um there
• 24:50
  is different red, there's sort of greens
• 24:54
  and all those mix together to give you
• 24:56
  something like a purple. Often in a
• 24:58
  bright aurora, you've got the green
• 25:00
  auroral curtains and below that there
• 25:02
  might be a purple layer as well. And
• 25:05
  sometimes the colors are so mixed that
• 25:06
  it turns white that you actually get a
• 25:09
  white bottom edge to an aurora. Then you
• 25:11
  know you've got really high energy
• 25:13
  electrons. And then
• 25:15
  >> so always seen one of those.
• 25:16
  >> Yes, I have. Uh yeah, actually the very
• 25:19
  first time we went up there, I've got
• 25:21
  photographs taken from a place called
• 25:23
  Lingan Fjord in northern Norway, a very
• 25:25
  dark site. It was a wonderful place to
• 25:27
  see the aurora from. And yeah, there
• 25:29
  were definitely white white bottoms on
• 25:31
  my auroral curves.
• 25:33
  Um, so, uh, but what I was going to say
• 25:38
  was that's the basic story, but in
• 25:41
  reality, you get these things all mixing
• 25:43
  and so sometimes you do get pinks and
• 25:45
  you get you can actually get some quite
• 25:46
  odd colors, almost browns. Actually, I
• 25:49
  took some photographs at the beginning
• 25:51
  of this year in uh far again far
• 25:53
  northern Norway uh and later in
• 25:56
  Greenland where the coloring was almost
• 25:58
  like a brown color rather than the the
• 26:00
  reddish that you expect uh from high
• 26:02
  altitude aurora. So, it it's the way the
• 26:04
  colors mix that give you the the
• 26:06
  different effects. Plus, you've got to
• 26:08
  add to that the color response of your
• 26:10
  camera as well, which can sometimes tell
• 26:13
  you, you know, give you falsehoods
• 26:16
  because the the the camera itself is is
• 26:19
  basically tuned to to take photographs
• 26:21
  of everyday objects. It's not really
• 26:23
  tuned to take photographs of things that
• 26:25
  are emitting only on one wavelength,
• 26:27
  which the aurora does.
• 26:28
  >> Yes. Yes, I know. Um although while we
• 26:31
  were uh up there um northern northern
• 26:34
  parts of Europe Norway um Greenland,
• 26:37
  Iceland um people did try to um take
• 26:41
  photos of Aurora and a couple of them
• 26:43
  were successful. I was not
• 26:46
  >> Yeah, I'll say one. But it was summer.
• 26:49
  >> Yeah, summer's the that's a problem
• 26:50
  because there's still so much twilight
• 26:52
  there. Um, I used to cut around a
• 26:55
  digital proper digital camera with me in
• 26:58
  a tripod to do all these long exposure
• 27:00
  photographs, but to be honest, now with
• 27:03
  a smartphone, they are so sensitive you
• 27:05
  can handhold them. Yeah.
• 27:07
  >> And get really fantastic auroral
• 27:09
  photographs. Um, which blew me away the
• 27:12
  first time I did it, which was the
• 27:14
  beginning of this year. Uh, I tried it a
• 27:17
  little bit on the previous trip that we
• 27:19
  had up to Northern Palace, which was in
• 27:21
  Canada, actually. Uh but this time at
• 27:23
  the beginning of this year in Norway,
• 27:25
  Sweden, Iceland, and Greenland, I just
• 27:27
  held the smartphone up and well, I've
• 27:30
  got more photographs than I know what to
• 27:32
  do with, and they're all dramatically
• 27:33
  good. Uh the smartphone is such amazing
• 27:36
  technology.
• 27:37
  >> It's changed the world,
• 27:39
  >> has in many ways, particularly when it
• 27:41
  comes to photography. It was the old um
• 27:44
  the old Canon snappies and all those
• 27:46
  that we used to have with film in them.
• 27:48
  You got one shot at it and you didn't
• 27:50
  find out if it was any good for a couple
• 27:51
  of weeks.
• 27:52
  >> Yeah. And the odds are that it it
• 27:54
  wouldn't be because this sensitivity of
• 27:56
  film is so much lower than the the you
• 27:58
  know than the sensors that we now use
• 28:00
  for images. That's the bottom line.
• 28:01
  >> Yep.
• 28:02
  >> Yeah. The gear is good now. Makes makes
• 28:04
  everybody a professional. Well, not
• 28:06
  quite, but you know what I'm saying.
• 28:07
  >> Talk to a professional photographer and
• 28:08
  they won't actually agree with that.
• 28:10
  >> No, they would they work hard.
• 28:12
  >> Uh, thank you Casey. Great question and
• 28:15
  good to hear from you again. Okay, we
• 28:17
  checked all four systems and being with
• 28:19
  the girls.
• 28:19
  >> Space nets.
• 28:21
  >> Our final question today. Uh, hi guys.
• 28:24
  Love the show, etc., etc. He doesn't
• 28:27
  bandandy around much. He's straight to
• 28:29
  the point. Uh, an idea just occurred to
• 28:31
  me. Uh, mass increases the faster you
• 28:34
  go, becoming infinite at the speed of
• 28:37
  light. So, if it were possible to
• 28:39
  accelerate particles up to rel
• 28:42
  relativistic, I hate that word,
• 28:44
  relativistic speeds in some compact
• 28:47
  device and then throw them out of the
• 28:49
  back of a spacecraft, would the
• 28:51
  acceleration increase because you're
• 28:54
  throwing more mass out the back? Yeah, I
• 28:57
  did that the other day. It's not
• 28:59
  pleasant. Um, kind of an ion engine on
• 29:03
  on steroids. Uh, I'm envisioning some
• 29:06
  kind of small particle accelerator
• 29:08
  powered by a nuclear power source,
• 29:10
  preferably fishing. Any thoughts?
• 29:13
  Absolutely. Welcome. Uh, many thanks and
• 29:15
  keep up the great work. Lee in Sweden,
• 29:18
  not to be confused with Swed Leon.
• 29:23
  >> Oh, okay. Really?
• 29:24
  >> Yeah, that's somebody else.
• 29:27
  >> Um, no, Lee in Sweden. So, um, okay.
• 29:31
  Okay. So, he's he's got a particle
• 29:33
  accelerator on his spaceship and he's
• 29:35
  he's accelerating the particles up to
• 29:38
  relativistic speeds and then he's
• 29:42
  shooting them out the back of the
• 29:43
  spacecraft, bigger mass, whatever. Can
• 29:46
  it accelerate the spacecraft?
• 29:49
  Um, yeah. All right. I'm going to read u
• 29:52
  what I've just put up brought up on the
• 29:55
  screen in front of me. Um, relativistic
• 29:58
  mass ejection in ion motors is not a
• 30:00
  current technology but a theoretical
• 30:02
  concept for future propulsion where ions
• 30:05
  would be accelerated to speeds
• 30:07
  approaching the speed of light. The
• 30:08
  relativistic aspect refers to the effect
• 30:11
  of special relativity where an object's
• 30:13
  mass appears to increase as it
• 30:15
  approaches the speed of light making it
• 30:17
  harder to accelerate it further. This
• 30:19
  would require extremely high energy
• 30:21
  inputs and would involve complex physics
• 30:24
  unlike current ion thrusters that use
• 30:26
  less energetic but still very high ion
• 30:29
  ejection velocities that came from AI.
• 30:33
  So how's that?
• 30:34
  >> Yeah. Well, I mean AI can be very
• 30:38
  useful.
• 30:39
  >> That's kind of what
• 30:40
  >> steer you up the the wrong path. It kept
• 30:42
  getting Yeah. Like I had to make some
• 30:44
  pretty significant inquiries
• 30:47
  last uh last year, early this year,
• 30:49
  whatever, uh about a a housing situation
• 30:52
  and it just got it so wrong constantly.
• 30:56
  >> Yeah.
• 30:57
  >> Um but yeah. Um
• 31:00
  >> so what I've just read out is putting
• 31:02
  nicely into words what I was going to
• 31:05
  say, but it's putting it rather more
• 31:07
  nicely than I would have put it. So
• 31:09
  there you go.
• 31:10
  >> Yeah. All right. So the the concept of
• 31:15
  um creating engines that can do these
• 31:19
  kinds of things is real in science but
• 31:22
  only to a certain degree.
• 31:24
  >> Yeah. My only worry about it would be um
• 31:27
  and I guess this is what you know the
• 31:29
  complex physics bit was. You've got um
• 31:33
  you've got different reference frames.
• 31:35
  You've got the reference frame of the of
• 31:37
  the spacecraft. You've got the reference
• 31:38
  frame of the flow of of charged
• 31:42
  particles coming out the back of it and
• 31:43
  you've got a stationary reference frame
• 31:46
  and and the mass looks different to all
• 31:48
  of those.
• 31:49
  >> Uh so uh that will be my only worry
• 31:53
  about that and it's the thing that I
• 31:54
  would like to go a bit further into it
• 31:56
  rather than rely on AI. Uh but the but
• 31:59
  the basic principle I think is is quite
• 32:02
  right. Uh but I would be I have a caveat
• 32:06
  about just watch out for your reference
• 32:08
  frame if I can put it that way.
• 32:10
  >> Yeah. Um I I've been toying with AI just
• 32:14
  to sort of get some concepts in my head
• 32:16
  about you know I mentioned I don't know
• 32:19
  if it was this podcast or the previous
• 32:20
  one where we uh where I'm writing a new
• 32:23
  book but um
• 32:25
  I there's some concepts I wanted to
• 32:28
  include but I my brain wouldn't go
• 32:30
  there. So, um, I did use AI to try and
• 32:34
  learn what I needed to learn to make the
• 32:37
  the thing work the way it wanted to in
• 32:39
  the story. Uh, it's very clever when you
• 32:41
  want to do things like that.
• 32:43
  >> Did it help?
• 32:44
  >> Yeah, very much.
• 32:45
  >> Oh, that's interesting.
• 32:46
  >> Yeah. Yeah.
• 32:47
  >> Um, in fact, it it sometimes gave me way
• 32:50
  too many concepts. I only wanted one,
• 32:53
  but it gave me 10. And I'm thinking,
• 32:54
  "Oh, hang on.
• 32:56
  That's all good stuff. I can't use it
• 32:58
  all." So, I had to pick. But um
• 33:02
  I I found it very useful. But um if you
• 33:06
  use it the right way, it's a it's a
• 33:07
  great tool.
• 33:09
  >> But if um yeah, for general information,
• 33:13
  sometimes it can just hit the you
• 33:16
  throwing a dart and hitting that metal
• 33:18
  thing around the edge.
• 33:19
  >> All right. Okay.
• 33:20
  >> Cuz it's it's throwing information back
• 33:22
  at you that's too generic, I suppose.
• 33:26
  >> Yeah. Yeah. Sometimes
• 33:28
  >> I think when it comes to AI, you've got
• 33:31
  to know how to use it to get the best
• 33:33
  out of it. Otherwise,
• 33:35
  >> that's right. Yes.
• 33:36
  >> Otherwise, it's dangerous.
• 33:38
  >> Yeah. The wrong path.
• 33:40
  >> Absolutely true. Yeah. I have found it
• 33:42
  very handy for like I've I've had a few
• 33:46
  photos over the years that I've wanted
• 33:47
  to keep, but they they've not been
• 33:49
  really good photos and it's been really
• 33:52
  good at cleaning them up, taking taking
• 33:54
  out some of the um there's one
• 33:56
  particular photo that I really love, uh
• 33:58
  but it's it's grainy.
• 34:00
  >> Yeah.
• 34:00
  >> So, I I you just upload the photo and
• 34:03
  say, "Can you um I can't remember the
• 34:06
  terminology I use, but um can you do
• 34:08
  this?" and it takes like a minute or two
• 34:11
  to rec calibrate the photo and then it
• 34:15
  gives you its result. And uh I had a
• 34:19
  couple of big hits with that that well,
• 34:22
  but I've had a couple that didn't.
• 34:24
  >> Yeah.
• 34:24
  >> Um because the um it had to try and fill
• 34:28
  in spaces because of the graininess of
• 34:31
  the photo
• 34:32
  >> and what it filled them in with actually
• 34:34
  changed the subject too much and I
• 34:35
  didn't like it. that makes any sense at
• 34:38
  all.
• 34:39
  But um yeah, I I do find it useful, but
• 34:42
  um it it's not a perfect science and you
• 34:45
  got to keep that in mind.
• 34:47
  >> Uh Lee, thanks for your question. Did we
• 34:49
  finish with Lee? I'm pretty sure we did.
• 34:51
  Yeah, good on you, Lee. Hope all is well
• 34:53
  in Sweden and I'm sure you get to see
• 34:55
  lots of Aurora, too, you lucky duck.
• 34:58
  >> Um that's it, Fred. We are finished.
• 35:01
  Thank you.
• 35:03
  >> Uh you're welcome.
• 35:07
  Yeah. Uh I um I've enjoyed uh going
• 35:10
  getting my mind bent around some of
• 35:12
  those issues myself. So, thank you Space
• 35:15
  Nuts listeners. You keep me on my toes.
• 35:17
  >> Yes, they do, don't they? If you would
• 35:19
  like to send us a question, uh you can
• 35:22
  do that through our website,
• 35:23
  spacenutspodcast.com
• 35:25
  or spacenuts.io
• 35:28
  and you click on the AMA link at the top
• 35:31
  of the homepage and uh just fill in the
• 35:34
  blanks. So, you can send us your text
• 35:36
  questions that way, or you can send us
• 35:38
  an audio question if you've got a device
• 35:41
  with a microphone. And just uh remember
• 35:42
  to tell us who you are and where you're
• 35:44
  from. Most people do these days. Uh or
• 35:46
  you can send us questions via YouTube.
• 35:48
  We've been getting a few of those. And
• 35:50
  sometimes they just turn up on social
• 35:52
  media. Uh it doesn't matter. We'll um
• 35:54
  we'll get to them. Although on social
• 35:56
  media, the audience tends to deal with
• 35:59
  them for us. So, um not many of them
• 36:01
  filter through. But, uh, yeah, keep, uh,
• 36:03
  those questions coming. Um, and, uh,
• 36:06
  yeah, that'll all be good. Uh, Fred,
• 36:08
  we'll see you next week. I think it'll
• 36:10
  be our last couple of programs before
• 36:11
  the Christmas break.
• 36:13
  >> May well be. That's right. We'll see.
• 36:15
  >> All right. We'll catch you then. Thanks,
• 36:16
  Fred. Sounds great.
• 36:17
  >> And thanks to Hugh in the studio who
• 36:19
  went supernova on us because he's got a
• 36:21
  lot of heavy elements and he's gone to
• 36:23
  see a dietician. And from me, Andrew
• 36:25
  Dunley, thanks for your company. We'll
• 36:27
  see you on the next episode of Space
• 36:28
  Nuts. Bye-bye.
• 36:30
  >> Space Nuts. You'll be listening to the
• 36:32
  Space Nuts podcast
• 36:35
  >> available at Apple Podcasts, Spotify,
• 36:38
  iHeart Radio, or your favorite podcast
• 36:41
  player. You can also stream on demand at
• 36:43
  byes.com. This has been another quality
• 36:46
  podcast production from byes.com.