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Gravity Questions, Cosmic Energy & Hidden Galaxies | Space Nuts: Astronomy Insights & Cosmic... · Space News Today

• 0:00
  Hi there. This is Space Nuts Q&A. My
• 0:02
  name is Andrew Dunley. Great to have
• 0:04
  your company. Coming up on this episode,
• 0:05
  we'll answer questions from Steve, Gus,
• 0:08
  and Nick. Uh Steve and Gus are sort of
• 0:10
  focused on the same thing, gravity.
• 0:13
  Steve wants to know if it can exist
• 0:16
  without mass. Uh and and Gus is talking
• 0:18
  about gravity and energy, and what's the
• 0:21
  relationship? And Nick is asking about
• 0:24
  galaxy movements, and are any moving
• 0:26
  towards us that we can't see yet?
• 0:29
  Well, we don't know. We can't see them
• 0:31
  yet. Uh, but we'll see if we can tackle
• 0:33
  all of that on this episode of Space
• 0:36
  Nuts.
• 0:36
  >> 15 seconds. Guidance is internal. 10 9
• 0:41
  Ignition sequence start.
• 0:43
  >> Space nuts.
• 0:44
  >> 5 4 3 2
• 0:46
  >> 1 2 3 4 5 5 4 3 2 1
• 0:49
  >> Space Nuts.
• 0:50
  >> Astronauts report. It feels good.
• 0:52
  >> Here he is again. Professor Fred Watson.
• 0:55
  Hello, Fred. Hello, Andrew. Hello. How
• 0:58
  are you doing now?
• 1:00
  >> I'm doing the same as I was before.
• 1:04
  >> How about you?
• 1:05
  >> Uh, well, I'm I'm still doing the same
• 1:07
  as I was before. Yes, that's right. And
• 1:10
  I hope to be doing the same again very
• 1:11
  soon.
• 1:12
  >> Yes, indeed. Yes. Shall we just sort of
• 1:17
  muck in and get these questions sorted
• 1:19
  out? I I it was a like a couple of weeks
• 1:23
  ago we we had um gravity questions
• 1:26
  coming in thick and fast. Uh no black
• 1:28
  hole questions but today it's gravity
• 1:30
  questions this
• 1:31
  >> and our first our first one comes from
• 1:34
  Steve.
• 1:35
  >> Hi guys, my name is Steve. I'm uh from
• 1:38
  New Zealand. Um really enjoy your show.
• 1:43
  recently read a article
• 1:46
  implying that uh gravity could be
• 1:50
  possible without mass
• 1:53
  and um I'm wondering if that would be uh
• 1:57
  another alternative explanation uh to um
• 2:02
  uh to dark matter and to uh Mond.
• 2:07
  Yeah, I don't know if that makes it very
• 2:09
  clear to you. Anyway, thanks. All right.
• 2:11
  Uh Steve, thanks for the question.
• 2:13
  Gravity without mass. Well, I doubt that
• 2:17
  uh we can turn to the Catholic Church
• 2:19
  because they do they do have mass. Um
• 2:22
  but
• 2:24
  [Music]
• 2:27
  terrible. Uh it's an interesting
• 2:28
  question though. It is. And um so yeah,
• 2:33
  my reading on this, excuse me, is is
• 2:36
  yes. Um that's correct. So, uh, actually
• 2:41
  there's a nice thread about this on
• 2:43
  Reddit if anybody looks at that website.
• 2:46
  >> I do. And, uh, well, I love Reddit.
• 2:49
  >> Yeah.
• 2:52
  I'm really, well, I do remember my, uh,
• 2:54
  one of my sons was an absolute Reddit
• 2:56
  fiend at one time. He was very much um,
• 3:00
  a Reddit fan. Uh, now, so that's how I
• 3:04
  was aware of it. But um, but I haven't
• 3:06
  been a great user of Reddit. But the
• 3:08
  bottom line, excuse me, is
• 3:11
  um and and this is the way is phrased in
• 3:15
  this particular conversation. If you
• 3:18
  increase the temperature
• 3:20
  of an object and they take a planet in
• 3:24
  this case uh and in fact I might just
• 3:27
  read it uh because this kind of is quite
• 3:30
  interesting.
• 3:32
  and
• 3:34
  take your Neptune you take your
• 3:36
  Neptunian planet something the size of
• 3:38
  Neptune raise the temperature by 300°
• 3:40
  Kelvin instantly now the mass of Neptune
• 3:44
  is about 10 26 kg and if we roughly
• 3:47
  assume all its hydrogen uh uh
• 3:49
  corresponds to about 6 * 10 52 particles
• 3:53
  of hydrogen uh it's the thermal energy
• 3:56
  is roughly given by an equation there E=
• 3:59
  NT
• 4:01
  uh uh which leads to an increase in
• 4:03
  thermal energy
• 4:06
  uh of da d and it's a large number of
• 4:10
  jewels um actually it's a small number
• 4:13
  of jewels it's k * 6 * 10 - 52 * 300
• 4:18
  jewels
• 4:20
  uh which um if you then convert that so
• 4:24
  so what what this is saying is you you
• 4:26
  you warm up a planet you get an increase
• 4:29
  uh in the thermal energy of that planet.
• 4:32
  You can then use E= MC² to convert that
• 4:35
  thermal energy into mass and in this
• 4:38
  case it comes out to be something like 3
• 4:40
  * 10 15 kg which is a lot but uh is not
• 4:47
  very much in comparison with a planet.
• 4:49
  Uh but that does mean that adding energy
• 4:53
  to something will increase its
• 4:55
  gravitational mass. Now um the Steve's
• 5:00
  sort of uh you know um next step in the
• 5:04
  argument from that is whether that could
• 5:06
  be misleading us in the idea of dark
• 5:08
  matter and things of that sort. Um and
• 5:13
  uh I I can't really get my head around
• 5:15
  how that would work. Um he mentioned M
• 5:18
  as well the modified Newtonian dynamics.
• 5:21
  Uh because my understanding is that
• 5:25
  everybody who looks at these
• 5:28
  particular problems what is dark matter?
• 5:30
  What is dark energy? They take into
• 5:32
  account everything. Uh I've read some of
• 5:35
  the papers on this. And so things like
• 5:39
  um you know gravitational
• 5:41
  uh gravitational influence of of pure
• 5:45
  energy and in this case we're talking
• 5:47
  about heat energy. Uh that uh is likely
• 5:52
  to be something that would be already in
• 5:54
  the equations. Um so I don't think it's
• 5:56
  the answer but it's a really interesting
• 5:58
  suggestion and an interesting thing to
• 6:00
  think about. Uh so thank you very much
• 6:03
  Steve.
• 6:04
  >> Yeah indeed. um just made me wonder, are
• 6:07
  we increasing Earth's gravity because
• 6:09
  we're heating the planet up?
• 6:11
  >> Yep, that's probably right. Um that I
• 6:15
  mean the the example that uh I just read
• 6:17
  out was about three t 300
• 6:20
  300° Kelvin, an instant uh increase in
• 6:24
  that. We're talking about one or two
• 6:26
  degrees Kelvin. uh but uh which makes a
• 6:29
  big difference to the earth's atmosphere
• 6:31
  but probably not that much difference to
• 6:32
  its uh you know gravitational potential.
• 6:36
  M okay. So the answer is yes. Gravity
• 6:38
  can exist without mass but it's probably
• 6:42
  not a major factor. Is that fair enough?
• 6:46
  >> Uh yes that is right. Um I just been
• 6:50
  dragging through my memory Andrew
• 6:52
  something else that's sort of vaguely
• 6:55
  related to this. Um which is the and we
• 6:59
  haven't used this name but we did talk
• 7:01
  about it a while ago the cougal blitz.
• 7:04
  And do you know what a cougall blitz is?
• 7:06
  >> Uh look, I've heard this before. Uh no,
• 7:10
  remind me.
• 7:11
  >> Yeah. So it's it basically is uh a black
• 7:15
  hole made of light. Uh it's and
• 7:18
  Wikipedia says it's a concentration of
• 7:20
  heat, light, or radiation so intense
• 7:22
  that its energy forms an event horizon
• 7:24
  and becomes selftrapped. In other words,
• 7:26
  if enough radiation is aimed into a
• 7:28
  region of space, the concentration of
• 7:31
  energy can walk spaceime so much that it
• 7:33
  creates a black hole. It's a black hole.
• 7:36
  It is a black hole whose original mass
• 7:39
  energy was in the form of radiant energy
• 7:41
  rather than matter.
• 7:43
  Uh now um there is a paper that was
• 7:46
  published in
• 7:49
  2024
• 7:50
  that concludes that a phenomenon like
• 7:53
  this cannot occur in any realistic
• 7:55
  scenario within our universe. So cougal
• 7:58
  blitzes are a theoretical entity that
• 8:01
  are not are thought not to occur in
• 8:04
  nature. Uh but it is a similar thing
• 8:07
  isn't it? It's a it basically it's a
• 8:09
  it's a black hole made of energy.
• 8:11
  >> Yeah. Wow, that's really interesting. I
• 8:14
  tell you something else that does exist
• 8:15
  is a Google Scriber. So, so
• 8:19
  I've got one of those. Have you?
• 8:22
  >> Yeah, there it is.
• 8:24
  >> It's a pen. It's German.
• 8:26
  >> Hold it up. Ah, okay.
• 8:28
  >> Cougle scriber.
• 8:29
  >> A cougriber.
• 8:31
  >> Yes.
• 8:32
  >> Do you know what German is? You know
• 8:33
  what the German is for pencil?
• 8:35
  >> Uh, I probably did once, but I don't
• 8:37
  now. That's
• 8:38
  >> bliff blift.
• 8:41
  >> All right.
• 8:42
  >> It's probably
• 8:44
  I only I did languages at high school
• 8:47
  and I was very good at them and I should
• 8:48
  have probably pursued that somewhere
• 8:50
  along the line, but German stuck with
• 8:52
  me. I some of the references I still
• 8:55
  remember today. Someone's going to
• 8:57
  correct me now because I'd probably
• 8:58
  bugger it up the pronunciation.
• 9:01
  >> Anyway,
• 9:02
  >> that's all right.
• 9:03
  >> I'm just showing off now. No, it's a
• 9:04
  it's a side of your character that I was
• 9:07
  unaware of. Um, Andrew, I um, curiously,
• 9:11
  I uh never joined never joined Lurman at
• 9:14
  school. I never learned German at
• 9:17
  school. Um, but, uh, uh, when I was 14,
• 9:22
  uh, I went on a school exchange to
• 9:25
  Germany, which was bar because I wasn't
• 9:27
  studying German, but that that was my
• 9:29
  first overseas visit, of course, from
• 9:31
  the United Kingdom. Um, and so I've
• 9:34
  spent the the however many years it is,
• 9:38
  60 odd years since then, trying to learn
• 9:41
  German.
• 9:43
  And um, yeah.
• 9:45
  >> Yeah. Look, I'm so jealous of students
• 9:48
  in countries like the United States and
• 9:50
  the UK and Europe because they get to do
• 9:53
  excursions to other countries. In
• 9:55
  Australia, we got to do excursions to
• 9:57
  Sydney and Canra. I mean, come on.
• 10:02
  That was it.
• 10:03
  >> Yeah,
• 10:04
  >> that was as good as it got for us.
• 10:06
  >> Yeah.
• 10:06
  >> I mean, these days they get to go to New
• 10:08
  Zealand once in a while. Um, but yeah,
• 10:11
  we we're so far from everywhere, it's
• 10:13
  just not easy. Although, my son did go
• 10:15
  to go get to do a couple of weeks in
• 10:17
  Japan through high school. So,
• 10:19
  >> there you go.
• 10:19
  >> There are a few options these days.
• 10:22
  >> This is Space Nuts. Andrew Dunley here
• 10:23
  with Professor Fred Watson.
• 10:28
  >> Three, two, one.
• 10:31
  Space nuts.
• 10:33
  >> Uh, we better keep moving. Uh, thank
• 10:34
  you, Steve. Let's get a question from
• 10:37
  Gus.
• 10:38
  >> Hello, Professor Fred and, uh, Andrew.
• 10:42
  This is Gus Iverson from Isiqua,
• 10:44
  Washington. I sent in a question for you
• 10:46
  guys previously, and you thought I was
• 10:47
  in Western Western Australia.
• 10:50
  >> Yes. I I've been thinking about uh uh
• 10:53
  gravity uh today and it it came to my
• 10:57
  mind that if uh energy and mass are
• 11:01
  equivalent then essentially uh shouldn't
• 11:05
  energy also create gravity at some
• 11:09
  level.
• 11:11
  Um I'm not sure if this is a related
• 11:14
  question or or an extension or or a
• 11:17
  separate question though. Um uh
• 11:19
  additionally
• 11:21
  um if a body of of any size is
• 11:25
  generating uh or has mass and it is
• 11:29
  generating a gravitational field,
• 11:33
  does not that field itself
• 11:37
  have energy and mass? And would that
• 11:41
  field not create additional gravity by
• 11:46
  its simple existence?
• 11:48
  So, if that's the case, or even kind of
• 11:53
  the case, my question is where does the
• 11:55
  energy and mass go if if um or
• 12:00
  uh I I I have no idea where to go with
• 12:04
  this. Thank you. Uh I love love the show
• 12:06
  and appreciate being able to ask
• 12:08
  questions.
• 12:09
  >> Thank you, Gus. Uh that sounded very
• 12:11
  much like something from Catch 22. Yeah.
• 12:14
  Was it was it apples or tomatoes? They
• 12:16
  were trying to I don't know. Um but uh
• 12:20
  yeah, it sounded a bit like that. Um
• 12:22
  gravity plus energy. Body plus mass plus
• 12:25
  gravity equals energy. But then does
• 12:28
  that add mass which adds to gravity? I
• 12:31
  think that's what he was trying to
• 12:32
  >> Yeah, that's right. So So you've got to
• 12:35
  you know the whole thing gets completely
• 12:37
  out of hand cuz everything's got
• 12:39
  gravity. Um I think uh so the first part
• 12:42
  of what Gus was saying is what we've
• 12:44
  just been talking about. You know if you
• 12:46
  put it into energy and mass
• 12:49
  >> um and
• 12:52
  gravitation you got be I probably have
• 12:55
  to be careful with the words
• 12:57
  gravitational gravitation is a potential
• 13:01
  uh an object in a gravitational field
• 13:03
  has potential energy. So, it does have
• 13:05
  energy. Uh, but it I I kind of need to
• 13:10
  take this one and notice. Actually, you
• 13:12
  did give me notice, Andrew, but I didn't
• 13:14
  have time to really look further into
• 13:16
  it. But I think um I think there's a I
• 13:20
  think there's a stumbling block
• 13:21
  somewhere in that argument. Uh, which is
• 13:23
  probably that gravitational energy isn't
• 13:25
  energy that's convertible to mass. Um,
• 13:29
  but I need to get my thoughts clearer on
• 13:32
  that, which they aren't at the moment.
• 13:34
  So Gus, thank you for a very uh tricky
• 13:37
  question uh which um I might think a
• 13:40
  little bit more about uh and
• 13:43
  >> uh perhaps we will revisit it in a
• 13:46
  future episode of Space Notes Q&A.
• 13:49
  >> I put a um I put a homework marker next
• 13:52
  to it.
• 13:53
  >> That's what I'm I'm just doing that. I'm
• 13:55
  doing it. You're doing it in your
• 13:57
  cougal.
• 13:59
  I'm using a red a red cougal scriber.
• 14:02
  Okay.
• 14:03
  I don't know what the German word for
• 14:05
  red is though.
• 14:06
  >> Oh, probably do it on translator.
• 14:10
  >> There you are.
• 14:11
  >> Yeah, there you are. I don't have to
• 14:13
  look it up.
• 14:13
  >> You don't.
• 14:14
  >> Um,
• 14:15
  >> so Gus, um, don't know. We don't know.
• 14:19
  Maybe, possibly. Could be. Don't know.
• 14:22
  >> There's the answer.
• 14:23
  >> Don't yet.
• 14:23
  >> How's that?
• 14:24
  >> Don't don't yet know.
• 14:28
  >> I like that.
• 14:29
  >> Yeah.
• 14:30
  >> Uh, let's um get to the final question.
• 14:32
  We'll get back to you Gus at some stage
• 14:35
  in Western Australia or it could be the
• 14:37
  United States. Uh now we've got a
• 14:39
  question from oh um just by coincidence
• 14:42
  from New Zealand again. Um hi team
• 14:46
  amazing podcast. Which one are you
• 14:47
  talking about now? Uh I have been
• 14:50
  listening since your early days and I've
• 14:52
  always uh looked forward to new uh
• 14:54
  uploads. My question is around the
• 14:56
  discovery of early galaxies from the
• 14:57
  James Webb Space Telescope. Is it
• 14:59
  possible for earlier galaxies to be
• 15:02
  traveling towards us that are currently
• 15:04
  out of reach? Uh filling with uh
• 15:07
  potentially nothing uh uh filling where
• 15:11
  potentially nothing was in view before.
• 15:13
  Uh if possible, would the light be
• 15:16
  compressed? How would the instruments
• 15:17
  deal with that? Hope that makes sense.
• 15:20
  Cheers, Nick from Oakland, New Zealand.
• 15:25
  Now, my brain just went, well, I suppose
• 15:27
  it's possible, but how do we prove it?
• 15:29
  until it happens.
• 15:30
  >> Yes. So, uh, couple of things in here.
• 15:32
  Um, thanks Nick. Great question. The
• 15:35
  last bit about light being compressed.
• 15:38
  So, um, and in a way that's, you know,
• 15:41
  that's, um, quite a nice way of putting
• 15:43
  it. So, anything that comes toward you
• 15:45
  that's emitting light, it's light will
• 15:47
  be blue shifted. In other words,
• 15:49
  >> it's wavelength will get shorter. And,
• 15:52
  and that's saying it's compressed is
• 15:55
  pretty well, you know, that's pretty
• 15:56
  well what happens. It's like uh um you
• 15:59
  know the the the good old uh ambulance
• 16:02
  siren or fire engine siren or whatever
• 16:04
  it is coming towards you uh which
• 16:06
  compresses the uh the sound waves and
• 16:09
  the result is an increase in pitch which
• 16:11
  corresponds to a shortening of
• 16:12
  wavelength. So that's standard physics
• 16:15
  we we can detect uh by the Doppler shift
• 16:18
  anything coming towards us uh by the
• 16:21
  fact that it light is shifted towards
• 16:22
  the blue end of the spectrum. Um but um
• 16:27
  the the first bit of the question about
• 16:30
  galaxies
• 16:32
  earlier galaxies traveling towards us um
• 16:36
  we
• 16:38
  we when we think about galaxies we have
• 16:41
  two
• 16:43
  two different velocities involved. One
• 16:45
  is the velocity of a galaxy as it's
• 16:48
  carried along by the expansion of the
• 16:50
  universe. uh and that is what we measure
• 16:54
  as a red shift. Uh the expansion of the
• 16:57
  universe is carrying galaxies away from
• 16:59
  us and so their light is being
• 17:01
  redshifted. Uh and by the time you get
• 17:04
  to these really early galaxies where
• 17:06
  you're looking back uh almost the whole
• 17:09
  edge of the universe, the red shift is
• 17:11
  very considerable. It's a factor of 13
• 17:13
  or 14 something like that. We're given
• 17:15
  the name zed. Uh the red shift is about
• 17:18
  14. So, um, a big part, no, that's not
• 17:21
  true. Uh, that's that's me confusing the
• 17:24
  age with the red shift. Forget that bit.
• 17:27
  But the the numbers quite high. The red
• 17:29
  shifts are probably five or six or
• 17:30
  something like that. Uh, but it's still
• 17:32
  it's still a a high level of the, you
• 17:35
  know, the light being stretched out by
• 17:36
  the expansion of the universe. So,
• 17:38
  that's one velocity, but galaxies can
• 17:41
  have a superimposed on that a velocity
• 17:44
  which we call a peculiar motion, its own
• 17:47
  velocity. uh caused by local, you know,
• 17:50
  local edies in space or whatever uh that
• 17:53
  that might um move a galaxy towards us.
• 17:56
  It's the gravitational field that it's
• 17:58
  exposed to. Very much like um the the
• 18:02
  analog is always a river carrying you
• 18:04
  along. Uh and if you're in a rowbo, you
• 18:06
  can move relative to the river, but the
• 18:08
  river is always carrying you along.
• 18:09
  That's exactly what's happening with the
• 18:11
  Hubble flow, the the expansion of the
• 18:13
  universe. And these peculiar motions are
• 18:15
  superimposed on that, but they're much
• 18:17
  much less
• 18:18
  >> than the motion uh at those distances or
• 18:22
  look back times. It's much much less
• 18:24
  than the expansion flow of the universe.
• 18:28
  So no, there won't be anything hidden
• 18:30
  from us that's coming towards us. I
• 18:31
  don't think it's a interesting
• 18:33
  suggestion, but uh everything's moving
• 18:35
  away from us at this very high velocity
• 18:37
  at those distances.
• 18:39
  >> Of course. Um, Nick, if you want to
• 18:41
  check with us in a million years or so,
• 18:43
  we might have an alternative answer.
• 18:45
  >> Well, that's true. Uh, put that in your
• 18:47
  diary and we'll we'll uh I'll I'll mark
• 18:49
  it with an asterisk knowing that it's
• 18:51
  homework for a million years time.
• 18:54
  >> Yes, it's good. Um, and I'm really
• 18:58
  disappointed that the people who make
• 18:59
  diaries haven't gone ahead that far yet.
• 19:06
  >> Thanks, Nick. Um, probably not, I think,
• 19:08
  is the the answer. Um, but thanks for
• 19:11
  the question. Thanks to everyone who
• 19:13
  sent in questions. Keep them coming. You
• 19:14
  can do that via our website,
• 19:15
  spacenutspodcast.com, spacenuts.io,
• 19:18
  which has two options. The AMA tab at
• 19:22
  the top where you can send us text and
• 19:23
  audio or the send us your questions uh
• 19:27
  button on the right hand side of our
• 19:28
  home screens. Don't forget to tell us
• 19:30
  who you are and where you're from. And
• 19:32
  you can probably upload your audio
• 19:34
  questions on any device as long as
• 19:36
  you've got a microphone and mobile
• 19:38
  phones are perfect for this. Uh but a
• 19:40
  lot of people have home computers with
• 19:42
  mics built in, etc., etc., etc. Always
• 19:45
  happy to hear from you. Uh Fred, thanks
• 19:48
  so much. We're done with another
• 19:50
  episode. Jeez, we're them up.
• 19:52
  >> We are wrapping them up. Good to talk to
• 19:53
  you, Andrew. And we'll speak again soon.
• 19:56
  >> Indeed, we will. Professor Fred Watson,
• 19:58
  astronomer at large. And thanks to Hugh
• 20:00
  in the studio for collecting
• 20:04
  not much, but uh we thank him anyway.
• 20:06
  And from me, Andrew Dunley, thanks for
• 20:07
  your company. See you on the very next
• 20:09
  episode of Space Nuts. Bye-bye.
• 20:12
  >> Space Nuts.
• 20:13
  >> You've been listening to the Space Nuts
• 20:15
  podcast
• 20:17
  >> available at Apple Podcasts, Spotify,
• 20:20
  iHeart Radio, or your favorite podcast
• 20:22
  player. You can also stream on demand at
• 20:25
  byes.com. This has been another quality
• 20:28
  podcast production from sites.com.