Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Stellar Insights: Light Speed, Cosmic Maps & Dark Energy Dilemmas

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Stellar Insights: Light Speed, Cosmic Maps & Dark Energy Dilemmas · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Heidi Campo: Welcome back to another fun Q and A episode
• 0:03
  of space nuts.
• 0:05
  Generic: 15 seconds. Guidance is internal.
• 0:07
  10, 9. Ignition
• 0:10
  sequence time. Space nuts. 5, 4, 3,
• 0:13
  2. 1. 2, 3, 4, 5, 5, 4,
• 0:16
  3, 2, 1. Space nuts. Astronauts
• 0:19
  report it feels good.
• 0:21
  Heidi Campo: I'm your host for this episode, Heidi Campo,
• 0:23
  filling in for Andrew Dunkley, who is on a
• 0:26
  cruise around the world. And joining
• 0:29
  us as always, is our beloved professor
• 0:31
  Fred Watson, astronomer at large.
• 0:35
  How are you doing today, Fred?
• 0:36
  Professor Fred Watson: Um, well, thank you, Heidi. Um, um,
• 0:40
  we heard from, uh, Andrew a few days ago,
• 0:43
  and, uh, he was heading to far northern
• 0:46
  Norway in his global cruise. He was going to
• 0:49
  North Cape, uh, which is the.
• 0:52
  It's not quite the northerly, most northerly
• 0:54
  point on the Eurasian continent, but
• 0:57
  it's very near it. Um, and
• 1:00
  there's a globe at the.
• 1:02
  Professor Fred Watson: End of North Cape, um, which sort.
• 1:03
  Professor Fred Watson: Of simulates kind of where you are on the
• 1:06
  Earth.
• 1:06
  Professor Fred Watson: It's a framework globe, but it's a.
• 1:08
  Professor Fred Watson: Very prominent spot for photography. I'm sure
• 1:11
  we'll see pictures of Andrew standing in
• 1:13
  front of it. I've got pictures of me standing
• 1:15
  in front of it, which I was doing in January,
• 1:18
  uh, not on a world.
• 1:18
  Professor Fred Watson: Cruise, but one of our Arctic tours.
• 1:20
  Professor Fred Watson: Um, I hope he's now vaguely on his way
• 1:23
  back home, because I don't.
• 1:25
  Professor Fred Watson: Think it's that long before he's supposed to
• 1:27
  emerge once again bright and happy
• 1:30
  in Australia. We'll have to look out for
• 1:32
  that.
• 1:32
  Heidi Campo: He's either going to be well
• 1:35
  rested or he's going to need a vacation to
• 1:37
  recover from this.
• 1:39
  Professor Fred Watson: Yeah, he might.
• 1:39
  Professor Fred Watson: That's right.
• 1:40
  Heidi Campo: I think sometimes a trip like that, you need
• 1:42
  some time to come back down from it.
• 1:45
  Professor Fred Watson: You do. And, um, yeah, they've got
• 1:48
  some interesting things. I won't go into
• 1:50
  them, but they've got some interesting things
• 1:51
  to look forward to when they get back. Um,
• 1:54
  which I'm sure Andrew will tell us all about
• 1:56
  when it.
• 1:57
  Professor Fred Watson: When it happens. Uh, that's just a teaser
• 1:59
  for, um, you know, when Andrew finally
• 2:01
  returns. Who knows when it'll be, but. That's
• 2:04
  right.
• 2:05
  Heidi Campo: Well, shall we get into our questions
• 2:08
  for today?
• 2:10
  Professor Fred Watson: Yeah, sounds good.
• 2:11
  Heidi Campo: So our first question today is from
• 2:15
  Rennie Trab from sunny, sunny West
• 2:18
  Hills, California. And Rennie says,
• 2:21
  I'm trying to understand the speed of light.
• 2:24
  What powers set what. Sorry,
• 2:26
  what power set it to? What speed
• 2:29
  is. How. How different
• 2:32
  would our universe be if the speed was lower
• 2:35
  or higher?
• 2:38
  Professor Fred Watson: That's an incredibly profound question from
• 2:41
  Rennie. And Rennie often does give
• 2:44
  us profound questions. Uh, what sets it
• 2:47
  to the speed it is um, we don't know.
• 2:50
  Um, we do know that the
• 2:53
  speed of light, 300,000 kilometers
• 2:56
  per second, if.
• 2:56
  Professor Fred Watson: I remember rightly, 186,000 miles per second,
• 2:59
  that used to be the number when.
• 3:01
  Professor Fred Watson: We did miles back in the UK. Um,
• 3:04
  300,000 kilometers per second, a lot easier
• 3:06
  to remember. That's the speed of light in a
• 3:08
  vacuum. It changes depending what it's going
• 3:10
  through. But the speed of light, the maximum
• 3:13
  speed limit of the universe, 300,000
• 3:15
  kilometers.
• 3:16
  Professor Fred Watson: Per second in a vacuum, uh, and.
• 3:18
  Professor Fred Watson: It'S set by simply,
• 3:21
  um, you know, it is what it is.
• 3:23
  It's set by the
• 3:26
  cosmic, um, setting of
• 3:28
  fundamental quantities, because that's what
• 3:31
  it is. Uh, but,
• 3:36
  uh, it's got
• 3:38
  extraordinary significance in our, uh,
• 3:40
  present understanding of the universe. Not
• 3:42
  just because it's what lets us look back in
• 3:45
  time. When we look out into space, we're
• 3:47
  always looking back in time because of.
• 3:49
  Professor Fred Watson: The finite speed of light.
• 3:52
  Professor Fred Watson: Um, if you looked out into space
• 3:54
  300,000km, you'd be looking back by a.
• 3:56
  Professor Fred Watson: Second because that's how long light takes to
• 3:59
  get here.
• 3:59
  Professor Fred Watson: So we know all about that. But
• 4:02
  it's more fundamental than that in that it
• 4:04
  doesn't change. Um, uh, and
• 4:07
  it's quite counterintuitive. If you imagine
• 4:09
  yourself in a spacecraft traveling along at
• 4:13
  maybe nearly the speed of light and you shone
• 4:15
  a torch out the front, you'd expect it to be
• 4:17
  going at nearly twice the speed of light.
• 4:19
  Professor Fred Watson: But it doesn't work like that. Light always
• 4:21
  travels at 300,000 kilometers per second.
• 4:24
  Professor Fred Watson: And in fact that was, you know, its
• 4:27
  origins come from work on
• 4:28
  electromagnetism done by,
• 4:32
  uh, um, great scientists, uh, during
• 4:35
  the 19th century. But it was Einstein who
• 4:37
  recognized its.
• 4:38
  Professor Fred Watson: Fundamental significance and that's what
• 4:41
  allowed him to build up the theories of
• 4:42
  relativ.
• 4:44
  Professor Fred Watson: Um, how different would our universe be if
• 4:46
  the speed was lower or higher? Yes, it would
• 4:48
  be, uh, it would change the
• 4:51
  universe. Uh, now in an extreme
• 4:54
  situation, uh,
• 4:57
  you might find, uh, some
• 5:00
  interest in. And
• 5:03
  I wouldn't mind betting that Rennie knows
• 5:06
  about this book, but I'll direct him to it
• 5:08
  anyway. Um, back in the
• 5:10
  1950s, a, uh, very well
• 5:13
  known physicist called George Gamow, uh,
• 5:16
  who made some quite significant discoveries
• 5:19
  in cosmology. Uh, he wrote
• 5:21
  a couple of books where he had a fictional
• 5:24
  hero called Mr. Tompkins. Mr.
• 5:27
  Tompkins had a hairstyle very similar.
• 5:28
  Professor Fred Watson: To mine because, uh, Gamow illustrated the
• 5:31
  book as well.
• 5:32
  Professor Fred Watson: Um, but, um, Mr. M. Tompkins had dreams
• 5:34
  and those dreams basically told you about
• 5:37
  physics. The first book was about relativity.
• 5:39
  Professor Fred Watson: The second one was Mr. Tompkins explores the
• 5:42
  Atom, uh, which, uh, is about atomic
• 5:45
  physics, the quantum world.
• 5:47
  Professor Fred Watson: Um, but one of the dreams that Mr. Tompkins
• 5:50
  has. Bet you never thought you'd be talking
• 5:53
  about this today on the show, Heidi. Um,
• 5:55
  he dreamt that the speed of light was, I
• 5:58
  think it was something.
• 5:58
  Professor Fred Watson: Like 25 miles an hour.
• 6:00
  Professor Fred Watson: It was ridiculously slow.
• 6:03
  But what it meant was that all the effects of
• 6:06
  relativity, which we know about,
• 6:09
  uh, were demonstrated at a very slow speed.
• 6:12
  Professor Fred Watson: This is special relativity, which is all
• 6:14
  about things moving close to the speed of
• 6:16
  light.
• 6:16
  Professor Fred Watson: Um, so he illustrated a picture of
• 6:19
  somebody riding a bicycle at, uh, nearly.
• 6:22
  Professor Fred Watson: The speed of light, 25 kilometers an hour.
• 6:24
  Sorry, 25 miles an hour.
• 6:26
  Professor Fred Watson: Uh, and showed, uh, the foreshortening, the
• 6:28
  fact that the bicycle seems to be.
• 6:30
  Professor Fred Watson: Squashed up, because that's one of the
• 6:33
  phenomena associated with travel near the
• 6:35
  speed of light.
• 6:36
  Professor Fred Watson: And there are other ones as well.
• 6:37
  Professor Fred Watson: Time travel, um, time dilation,
• 6:40
  your time changes.
• 6:42
  Professor Fred Watson: So it's a book. Um, I still think for all
• 6:45
  its, you know, gosh, it's, uh, 70 years.
• 6:47
  Professor Fred Watson: Out of date now.
• 6:49
  Professor Fred Watson: Uh, the relativity in it is still.
• 6:51
  Professor Fred Watson: Exactly as we understand it today, and it's
• 6:54
  worth a read.
• 6:54
  Professor Fred Watson: So I direct Rennie to that book.
• 6:57
  Heidi Campo: That is very interesting. I'm going to be
• 6:59
  wrapping my head around that one for a while.
• 7:03
  Our, uh, next question is an audio question,
• 7:06
  and this comes from Buddy in Oregon.
• 7:09
  And I'm going to give us just a second to cue
• 7:11
  that up and then all of our listeners will be
• 7:14
  able to hear Buddy's question as well. We're
• 7:16
  going to play that for you now.
• 7:19
  Buddy: This is Buddy from Ontario, Oregon. This is
• 7:21
  a quick one and I guess I'll let Fred
• 7:24
  explain. Uh, gravity and
• 7:27
  footed dark energy actually be
• 7:30
  weaker and stronger nuclear forces
• 7:33
  played out at a larger scale as secondary
• 7:36
  reactions. Hope that makes sense. Thanks,
• 7:38
  guys. Love the pod.
• 7:39
  Professor Fred Watson: I, I think Buddy might have had the same
• 7:42
  cold or fever that you.
• 7:44
  Professor Fred Watson: Had in the last episode.
• 7:48
  Professor Fred Watson: Yeah, it's not the. Not the Buddy we're used
• 7:50
  to hearing anyway. It's, um, it's an
• 7:53
  interesting question. So, uh,
• 7:56
  could gravity and dark energy,
• 7:59
  which are forces, uh, that
• 8:02
  we understand.
• 8:03
  Professor Fred Watson: Least in the quantum world. Gravity we're all
• 8:05
  familiar with, it's the one that pulls us
• 8:06
  down to the surface of the Earth.
• 8:07
  Professor Fred Watson: Dark energy is the property of
• 8:10
  space that we think causes the universe to
• 8:12
  expand, uh, in an accelerating manner.
• 8:16
  Uh, could those two forces be,
• 8:19
  uh, like the strong and weak nuclear force.
• 8:22
  Professor Fred Watson: Played out on a larger scale?
• 8:24
  Professor Fred Watson: Uh, I like his thinking. So
• 8:27
  let me just, um, Quickly, talk about the
• 8:29
  strong and weak nuclear force. There are
• 8:31
  four, we believe there are four fundamental
• 8:33
  forces of nature and they.
• 8:36
  Professor Fred Watson: Are electromagnetism, which is the
• 8:39
  force that is allowing us to talk now.
• 8:41
  Professor Fred Watson: And lets me see you and lets chemical
• 8:43
  reactions take place. Very important one. And
• 8:46
  then there are these two nuclear forces, the
• 8:48
  strong and weak nuclear forces,
• 8:51
  which, um, uh, determine the
• 8:54
  way atoms behave.
• 8:55
  Professor Fred Watson: Basically.
• 8:56
  Professor Fred Watson: Um, they are very well
• 8:58
  understood. They sound like uh, you know,
• 9:01
  two angles on the same thing, but they're
• 9:04
  not.
• 9:04
  Professor Fred Watson: They're quite different forces.
• 9:06
  Professor Fred Watson: But as Rennie
• 9:09
  has sort of. Sorry, I beg your pardon. As
• 9:13
  Buddy. Buddy.
• 9:16
  Sorry, Buddy. As Buddy has indicated,
• 9:19
  um, uh, they only operate on a small
• 9:22
  scale, they operate on the atomic scale.
• 9:24
  Professor Fred Watson: Those forces don't extend beyond.
• 9:28
  Professor Fred Watson: So to sort of, you know,
• 9:30
  hypothesize that maybe,
• 9:33
  um, gravity and dark energy. Dark energy we
• 9:36
  do not consider yet.
• 9:37
  Professor Fred Watson: To be a fundamental force because we really
• 9:39
  don't understand it.
• 9:40
  Professor Fred Watson: Ah, but could they be manifestations
• 9:44
  of.
• 9:44
  Professor Fred Watson: These other forces on a larger scale?
• 9:47
  Professor Fred Watson: And I do like his thinking. Um, I
• 9:51
  suspect that the fundamental
• 9:53
  physicists, the people who really know about
• 9:55
  this stuff, um, have ruled
• 9:58
  out something like that. But I wouldn't mind
• 10:00
  betting that there is, you know,
• 10:03
  it's almost like an.
• 10:04
  Professor Fred Watson: Analog one of the other that you've.
• 10:06
  Professor Fred Watson: Got these major forces that act on
• 10:09
  enormous timescales.
• 10:10
  Professor Fred Watson: In fact, they're infinite. Certainly, uh,
• 10:12
  gravity is. Gravity never fades away. It gets
• 10:15
  so small as to be measurable. Measurable, but
• 10:18
  never fades away.
• 10:19
  Professor Fred Watson: Maybe there's a nice analog between the two.
• 10:22
  Um, I don't know enough about nuclear, um,
• 10:25
  physics to be able to analyze it in any
• 10:28
  greater depth. But it's a question that I
• 10:30
  liked.
• 10:31
  Professor Fred Watson: Uh, and thank you very much, Bonnie.
• 10:35
  Andrew Dunkley: Three, two, one.
• 10:38
  Space nuts.
• 10:40
  Heidi Campo: Our next question is, uh, from Casey
• 10:43
  from Colorado. Casey says, hey
• 10:45
  guys, just learned about ASKAP
• 10:49
  J1832
• 10:51
  0911 and that it emits
• 10:54
  radio waves and x rays for 2 minutes every
• 10:57
  44 minutes. Is it true that no one
• 10:59
  knows what this is? Do you have any ideas?
• 11:02
  Fred, love the show and hope you're both
• 11:04
  well. Thanks.
• 11:06
  Professor Fred Watson: Yeah, um, this is a classic
• 11:09
  gobbledygook name. ASCAP
• 11:10
  J1832
• 11:13
  -09.11. ASCAP is
• 11:16
  the name of the telescope.
• 11:18
  Professor Fred Watson: Uh, that discovered this object. It's an
• 11:20
  abbreviation for the Australian Square
• 11:21
  Kilometer Array Pathfinder. It's an array of
• 11:24
  I think 36 dishes in Western
• 11:27
  Australia, uh, and a.
• 11:29
  Professor Fred Watson: Very radio quiet site. And the
• 11:31
  J1832 0911
• 11:34
  is just the.
• 11:34
  Professor Fred Watson: Coordinates in the sky of this object, what
• 11:37
  we call the right ascension and declination.
• 11:39
  So it's south of the equator. That's why it's
• 11:41
  got a minus sign in front of the nine.
• 11:44
  Professor Fred Watson: Um, it's ah, a nice way of naming things
• 11:47
  by giving them uh, their coordinates,
• 11:50
  uh, in the sky because then you pinpoint
• 11:52
  where it is and these.
• 11:53
  Professor Fred Watson: Coordinates are just like latitude and
• 11:54
  longitude on the Earth.
• 11:56
  Professor Fred Watson: So uh, to what it is. Um, well
• 11:59
  it uh, was discovered, as I said,
• 12:02
  by the Australian Square Kilometer
• 12:05
  Array pathfinder, but also
• 12:07
  um, by X ray observations
• 12:10
  with uh, something, um,
• 12:13
  some work that was done using the Chandra.
• 12:15
  Professor Fred Watson: X Ray observatory, one of NASA's great
• 12:17
  observatories in orbit. Because X rays don't
• 12:20
  penetrate the atmosphere, at least not in the
• 12:21
  energies that.
• 12:22
  Professor Fred Watson: We are looking at. Uh, and it
• 12:25
  turns out um, that this object
• 12:28
  is in a supernova remnant.
• 12:31
  So it's something that has exploded.
• 12:34
  Uh, and um, when you
• 12:37
  basically uh, look at the
• 12:40
  details surrounding the object.
• 12:42
  Professor Fred Watson: You can see that there's a shell.
• 12:44
  Professor Fred Watson: Of gas which is probably uh, the.
• 12:46
  Professor Fred Watson: Shockwave caused by the supernova.
• 12:49
  Professor Fred Watson: We don't know when that exploded, but uh, it
• 12:51
  was a long time ago. And
• 12:54
  so the properties um,
• 12:57
  that uh, we've already heard
• 13:00
  described, um, by Cayce,
• 13:03
  uh, this business of shining in X
• 13:06
  rays and radio waves exactly as uh.
• 13:09
  Professor Fred Watson: He says for two minutes every 44 minutes.
• 13:12
  Professor Fred Watson: That is still a mystery. Um,
• 13:15
  uh, it's thought that the source is something
• 13:18
  we call a magnetar. And a magnetar is
• 13:21
  a highly magnetic, uh,
• 13:24
  um, highly magnetic, um, neutron
• 13:26
  star, neutron stars being one
• 13:29
  of the possible remnants from a
• 13:32
  supernova explosion.
• 13:33
  Professor Fred Watson: The collapse of the core of the.
• 13:35
  Professor Fred Watson: Star into something very, very dense indeed,
• 13:39
  uh, weighing as much as a star.
• 13:41
  Professor Fred Watson: But with the dimensions of a city.
• 13:44
  Professor Fred Watson: Uh, that's a neutron star. Some of them are
• 13:47
  very m. Highly magnetized. They're called
• 13:49
  magnetars. And we think they have flares on
• 13:51
  them. And some of those flares are uh, what
• 13:53
  we think give rise to the.
• 13:56
  Professor Fred Watson: Fast radio bursts that are very much in the
• 13:58
  news as well.
• 14:00
  Professor Fred Watson: Uh, but this object is not like a fast radio
• 14:02
  burst because it shoots out these
• 14:05
  pulses, um, for two minutes.
• 14:08
  Professor Fred Watson: Whereas fast radio bursts are less than.
• 14:10
  Professor Fred Watson: A thousandth of a second, uh, two.
• 14:12
  Professor Fred Watson: Minutes every 44 minutes.
• 14:14
  Professor Fred Watson: And what that's telling you is that there's
• 14:16
  probably uh, something
• 14:19
  orbiting something else. Uh, so there
• 14:21
  might very well be uh, uh,
• 14:24
  the magnetar, uh, whose
• 14:27
  radiation is being shrouded by something
• 14:29
  else, uh, that uh, only allows
• 14:32
  it to see, uh, to be pointed in our
• 14:35
  direction every 44 minutes. It could also be
• 14:38
  directed radiation.
• 14:39
  Professor Fred Watson: Radiation that's squirting out from the pole
• 14:41
  of a magnetar.
• 14:43
  Professor Fred Watson: Uh, which means that there's a sort.
• 14:44
  Professor Fred Watson: Of lighthouse flashing effect as well. That's
• 14:47
  how pulsars work. They're uh, neutron stars
• 14:49
  that radiate at uh, their magnetic poles and
• 14:52
  as they.
• 14:52
  Professor Fred Watson: Rotate they sweep their radiation over the
• 14:55
  earth.
• 14:55
  Professor Fred Watson: And we see that.
• 14:56
  Professor Fred Watson: So there might be that going on plus
• 14:58
  something else that is, ah, either making
• 15:01
  the object wobble or hiding it. Um,
• 15:05
  uh, uh, there are lots of people scratching
• 15:07
  their heads about this, Cayce. Um, I
• 15:11
  hope, uh, that is,
• 15:13
  um, a reasonable, uh, explanation of
• 15:16
  what's going on. Um, at uh, least I
• 15:19
  think it.
• 15:20
  Professor Fred Watson: Uh, ties in with what I've read.
• 15:21
  Professor Fred Watson: So far about J
• 15:23
  1832
• 15:25
  -09.
• 15:27
  Professor Fred Watson: 11.
• 15:29
  Heidi Campo: What a name.
• 15:31
  Professor Fred Watson: Yeah, what a name.
• 15:36
  Voice Over Guy: 0G and I feel fine Space nuts.
• 15:40
  Heidi Campo: Our, uh, very last question is another audio
• 15:42
  question. And this is from Dean
• 15:45
  from Queensland. Queensland, I don't know
• 15:48
  how you pronounce that. Lots of, uh,
• 15:51
  discrepancies on pronunciation. Tomato,
• 15:53
  tomahto. Um, and this is an audio question,
• 15:55
  so we'll let you guys listen to it and we'll
• 15:58
  cue that up and play that for you.
• 15:59
  Andrew Dunkley: Now, Fred, Heidi and Andrew, this is Dean in
• 16:02
  Redcliffe in Queensland. My question is about
• 16:04
  m the image. It shows us the cosmic microwave
• 16:07
  background in space. I've assumed that this
• 16:10
  image represents the full 360 degrees of the
• 16:13
  entire sky as seen from all around the Earth.
• 16:16
  But I'm wondering if this is correct. If it
• 16:18
  shows all directions, it would be like
• 16:20
  looking at the internal surface of a sphere,
• 16:22
  which could also be projected onto the outer
• 16:25
  surface of a sphere in the same way we look
• 16:28
  at a globe of the Earth. There are many ways
• 16:30
  to project the sphere of the Earth's, uh,
• 16:32
  surface as a 2D image, but parts of it are
• 16:35
  always distorted, particularly around the
• 16:37
  edges. The 2D images of the
• 16:40
  CMB that I've seen are usually shown in an
• 16:42
  oval shape. Is the CMB image
• 16:45
  distorted around the edges? It might be, but
• 16:48
  it's hard to tell. Or is the image cropped in
• 16:51
  some way? Thanks again for the podcast.
• 16:54
  Professor Fred Watson: Yeah, that's a great question. Uh, it's one
• 16:56
  I've never had before,
• 16:59
  um, about the shape of the, our, uh,
• 17:02
  depiction of the cosmic microwave background
• 17:04
  radiation. Um, so,
• 17:07
  uh, Dean is absolutely right that that is
• 17:10
  a map, effectively a representation
• 17:13
  of the celestial sphere. And the
• 17:16
  celestial sphere is. If you imagine
• 17:19
  yourself floating in space, um,
• 17:22
  the sky would be all around you and you
• 17:25
  could imagine it as a sphere and that's
• 17:27
  basically how we imagine it flow from the
• 17:30
  Earth's surface.
• 17:31
  Professor Fred Watson: Although you only see half the sphere because
• 17:33
  the rest is blocked out by the Earth itself.
• 17:36
  Professor Fred Watson: Um, and what we call spherical astronomy
• 17:39
  is a, ah, really useful tool because it's
• 17:42
  what allows you to uh, put
• 17:45
  objects in the three dimensions of space into
• 17:48
  their context as seen from the Earth. Uh,
• 17:50
  uh, um, and the Earth's,
• 17:53
  you know, this depiction of the
• 17:56
  inside of uh, a sphere being
• 17:59
  representative of the sky.
• 18:01
  Professor Fred Watson: Uh, as I said, it's called the celestial
• 18:03
  sphere.
• 18:03
  Professor Fred Watson: A very useful tool. And so that's what's
• 18:06
  happened here. We see the
• 18:09
  cosmic microwave background radiation in
• 18:11
  every direction.
• 18:13
  Professor Fred Watson: Uh, as we observe it from Earth. It covers
• 18:15
  the whole of the celestial sphere. It's
• 18:18
  faint, it's in the microwave region of the
• 18:19
  spectrum.
• 18:20
  Professor Fred Watson: It's mottled, uh, because of
• 18:23
  um, uh, the slight variations in
• 18:25
  temperature.
• 18:26
  Professor Fred Watson: What we're seeing is the echo of the Big Bang
• 18:28
  there. The flash of the Big Bang, uh.
• 18:30
  Professor Fred Watson: Which is redshifted, uh, because of the.
• 18:33
  Professor Fred Watson: Expansion of the universe since that light
• 18:35
  was emitted 13.8 billion years ago.
• 18:38
  Professor Fred Watson: Um, but that's not what Dean's question's
• 18:41
  about. It's about uh, the projection.
• 18:43
  And um, so it's one
• 18:46
  that's very commonly used in maps of
• 18:49
  the world. Um, it's a projection of
• 18:53
  the sphere onto two dimensions. And it is
• 18:55
  called the Atoff projection. Named after
• 18:58
  19th century geographer I think, uh,
• 19:01
  called Dr. Atoff a I T O double
• 19:04
  F. Uh, it's sometimes called an
• 19:07
  equidistant azimuthal projection.
• 19:10
  Um, because the um, azimuths, that's
• 19:13
  what.
• 19:13
  Professor Fred Watson: You might call the longitude lines are.
• 19:15
  Professor Fred Watson: Uh, equal in distant. And Dean is
• 19:18
  right. Uh, all map M projections trying
• 19:21
  to project a sphere onto a flat piece of
• 19:23
  paper, they all have distortions.
• 19:26
  Uh, and this one does too, but they're pretty
• 19:29
  minor.
• 19:29
  Professor Fred Watson: And that's why it's used a lot in depictions
• 19:32
  of the whole sky. Like our depiction of the
• 19:35
  cosmic microwave background radiation.
• 19:37
  Professor Fred Watson: So there will be some distortion around the
• 19:39
  edge. Uh, not very high
• 19:42
  level, but you.
• 19:43
  Professor Fred Watson: Know, a little bit of distortion.
• 19:46
  Professor Fred Watson: Um, if you look at an Atoff projection uh,
• 19:49
  of the Earth, uh, you get an idea of
• 19:52
  the minimal amount.
• 19:53
  Professor Fred Watson: Of distortion that there are. The same would
• 19:55
  apply to the celestial.
• 19:58
  Professor Fred Watson: Sphere and the cosmic microwave background
• 20:00
  radiation. But the answer to the last part of
• 20:02
  Dean's question, no, it hasn't been cropped.
• 20:05
  That is the full, that's the whole.
• 20:07
  Professor Fred Watson: Sky depicted as a two dimensional
• 20:10
  map. So no cropping around the edge. That's
• 20:12
  exactly what There is uh, it's.
• 20:14
  Professor Fred Watson: Pretty easy to find, um,
• 20:17
  representations of the cosmic m. Microwave
• 20:19
  background radiation where it is actually
• 20:21
  shown as a globe. Uh, of course
• 20:24
  we're seeing it from the inside outwards, but
• 20:26
  you can represent.
• 20:27
  Professor Fred Watson: It as a globe as well. And if you've got
• 20:29
  animation, you can circulate the globe so you
• 20:31
  can see what it looks like on the other side.
• 20:34
  Professor Fred Watson: It's a lot easier to look at.
• 20:35
  Professor Fred Watson: It on a map like the projection that we've
• 20:37
  been talking about.
• 20:38
  Heidi Campo: It's quite interesting. I actually, I pulled
• 20:40
  it up while you were talking. Cause I always
• 20:42
  like having a visual. I have the two monitors
• 20:44
  going on and um, I'm seeing there's just,
• 20:47
  there's. So there's such a rabbit hole we can
• 20:49
  go down.
• 20:49
  And one. I'm gonna, I'm gonna, I'm gonna um,
• 20:52
  do a little follow up question to Dean's
• 20:54
  question. It looks like, it looks like
• 20:57
  um, there's an axis
• 21:00
  on the cosmic microwave background
• 21:03
  and that it lines up with our solar
• 21:05
  system. And that's kind of a point of
• 21:08
  interest and curiosity.
• 21:11
  Professor Fred Watson: Um, that's been something that's been
• 21:13
  commented on. There is. I mean, let me
• 21:16
  just explain what that depiction is exactly.
• 21:19
  It's uh, the microwave background. So the,
• 21:22
  and it's an ellipse, the Atoff projection.
• 21:24
  The long axis of the ellipse represents the
• 21:27
  equator, uh, of our galaxy.
• 21:29
  Professor Fred Watson: In other words the galactic plane.
• 21:31
  Professor Fred Watson: And that means that you, in some depictions
• 21:34
  of this, the microwave radiation from the
• 21:37
  galaxy itself hasn't been subtracted.
• 21:40
  Uh, and so you've got this sort of very
• 21:42
  bright area around the middle. But you're
• 21:45
  right, Heidi. I do remember that,
• 21:47
  um, people thought they could see an
• 21:50
  alignment with the plane of our solar system,
• 21:53
  which is.
• 21:53
  Professor Fred Watson: Quite steeply tilted to the galactic plane.
• 21:57
  Professor Fred Watson: Uh, and that is a concern.
• 21:59
  Professor Fred Watson: I'm not sure what the resolution of that
• 22:01
  issue was.
• 22:02
  Professor Fred Watson: I don't think it's been a showstopper.
• 22:05
  Professor Fred Watson: For the cosmic microwave background
• 22:06
  radiation. But I'll check up on that and try
• 22:08
  and find out uh, whether there's any further
• 22:11
  news, whether it's just disappeared with
• 22:13
  further analysis.
• 22:14
  Professor Fred Watson: I do remember people talking about it. There
• 22:16
  are three, um, when you look at the cosmic
• 22:19
  microwave background radiation, you'll.
• 22:20
  Professor Fred Watson: Usually come up with three different images.
• 22:22
  Professor Fred Watson: Um, and they're only different because of.
• 22:24
  Professor Fred Watson: The detail that they show.
• 22:26
  Professor Fred Watson: Uh, the first one came from cobe.
• 22:28
  Professor Fred Watson: Uh, which was a spacecraft Cosmic Background
• 22:30
  explorer in the 90s.
• 22:32
  Professor Fred Watson: Uh, then there was WMAP, the uh,
• 22:35
  Wilkinson Microwave Anisotropy Probe
• 22:38
  in the early 2000s. And then round about
• 22:40
  2010, the Planck.
• 22:41
  Professor Fred Watson: Spacecraft, a European spacecraft, which gave
• 22:44
  us the map. It's usually colored greenish. I
• 22:46
  don't know whether that's the one that you
• 22:47
  were looking at. That's the Planck one, which
• 22:50
  has the finest detail on M it. Because that
• 22:52
  was all about trying to tease out the
• 22:55
  detail in these models that are shown in the
• 22:57
  background radiation.
• 22:58
  Professor Fred Watson: Which tell us about the, the temperature.
• 23:01
  Professor Fred Watson: In the universe when the Big Bang was still a
• 23:03
  ball of fire.
• 23:06
  Heidi Campo: So fascinating. I'm, um. Actually, uh,
• 23:07
  there's an image I was looking at just now
• 23:09
  that had like a cross section of each, each
• 23:11
  one of those images side by side by side. Uh,
• 23:13
  but yes, so fascinating. I mean,
• 23:16
  that's probably a whole area of expertise
• 23:19
  for someone where they just specialize in the
• 23:22
  cosmic microwave background. And that's their
• 23:24
  whole thing.
• 23:24
  Professor Fred Watson: They do.
• 23:26
  Professor Fred Watson: They do, yeah.
• 23:26
  Professor Fred Watson: They do very serious mathematical analysis on
• 23:29
  those blobs, uh, which tell us
• 23:32
  about.
• 23:32
  Professor Fred Watson: Conditions in the early universe. It's really
• 23:34
  quite extraordinary what you can glean from
• 23:36
  it.
• 23:36
  Professor Fred Watson: And the thing that always fascinates me is
• 23:38
  that when you look at that.
• 23:39
  Professor Fred Watson: Image, you're looking at the oldest thing we
• 23:41
  can ever see. The flash of the Big Bang.
• 23:44
  Heidi Campo: Oh, man, this stuff gives me chills
• 23:46
  sometimes.
• 23:49
  And that's what gets me excited about some of
• 23:51
  these, uh, like new, New age
• 23:54
  telescopes like James Webb. I mean, that's
• 23:56
  really. It's changing, it's changing the
• 23:58
  game. We're able to see deeper and further,
• 24:01
  and it's just amazing what we're able to
• 24:04
  discover now. We're really on the cusp of so
• 24:06
  many amazing things. And I think you
• 24:08
  mentioned, um, you know, when you
• 24:11
  were, when you were young. This was in our,
• 24:12
  in our last episode that we recorded when you
• 24:15
  were young and hearing about some of these
• 24:17
  missions coming out and seeing these images
• 24:19
  for the first time and to see how far
• 24:22
  that this has all come and how much further
• 24:25
  we have yet to go is just such an incredible
• 24:27
  thing to think of.
• 24:28
  Professor Fred Watson: Yep, yep.
• 24:29
  Professor Fred Watson: The sky's the limit, Heidi.
• 24:33
  Heidi Campo: And maybe not even then. Maybe. Maybe the
• 24:35
  sky, the universe and beyond.
• 24:38
  Professor Fred Watson: Yes, that's right.
• 24:39
  Heidi Campo: Well, Fred, this has been another wonderful Q
• 24:42
  and A episode. Thank you so much for spending
• 24:45
  time with us, enlightening us and just, just,
• 24:48
  uh, giving us your knowledge
• 24:51
  and wisdom that you've spent a lifetime,
• 24:53
  um, garnering.
• 24:55
  Professor Fred Watson: Um, yes, it's good that it's been put to some
• 24:58
  good use, actually.
• 25:00
  Yeah, I've spent my life, uh,
• 25:03
  learning.
• 25:04
  Professor Fred Watson: Facts about the universe, and it's nice to be
• 25:05
  able to talk about them.
• 25:07
  Professor Fred Watson: With somebody like you.
• 25:08
  Professor Fred Watson: Thank you.
• 25:09
  Heidi Campo: Thank you so much. Well, uh, on that positive
• 25:11
  note, we will catch you all next time.
• 25:15
  Professor Fred Watson: Space Nuts.
• 25:16
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• 25:18
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