Special Episode: Live from DragonCon 2014!

Live from DragonCon 2014! Fraser and Pamela are joined by Les Johnson, Scott Edgington, Erin MacDonald, Roy Kilgard, and Fraser bombards all of these wonderful scientists with the hardest, most complicated questions he can come up with!

Dr. Erin MacDonald holds a PhD in Astrophysics and up until this year was working as a postdoctoral researcher for the LIGO Scientific Collaboration conducting research in gravitational waves and gamma-ray bursts. She is now producing and directing a documentary about postdoctoral research life and working as an educator at the Denver Museum for Nature and Science in Colorado.

Dr. Scott Edgington is a Planetary Scientist at the Jet Propulsion Laboratory whose serves as Cassini’s Deputy Project Scientist and Investigation Scientist for Cassini’s thermal infrared instrument.

Dr. Roy Kilgard is an astrophysicist who researches black holes in nearby galaxies with an emphasis on intermediate-mass black holes: an enigmatic class of objects whose origins are unclear. When not studying the heavens, he lectures on astronomy in science fiction and pop culture.

Les Johnson is an author of science fiction and popular science books and a NASA scientist. His recent novel, Rescue Mode (Baen, 2014), is a collaboration with Ben Bova. Les was the featured Interstellar Explorer in National Geographic magazine (January 2013) and a technical consultant for the movie, Europa Report.

Download the show [MP3] | Jump to Shownotes | Jump to Transcript

This episode is sponsored by: Swinburne Astronomy Online, 8th Light

Show Notes

  • How Should You Pronounce Uranus? — Universe Today
  • Travel Inside a Black Hole (video)
  • Disney’s “Black Hole”
  • Why We’ll Probably Never Build a Space Elevator — i09
  • Space Tethers
  • Saturn’s Rings May be Old Timers — NASA
  • The Shape of the Universe from WMAP
  • Which Came First: The Galaxy or Black Hole? — NPR
  • Fermi Paradox — SETI
  • Can a Really, Really Fast Spaceship Turn into a Black Hole? — Universe Today
  • Where Should We Look for Life in the Solar System? — Universe Today
  • Calculating God by Robert J. Sawyer
  • Are we living in a simulation? Philosophy paper by Nick Bostrom
  • Thoughts (and math) on time before the big bang — Universe Today
  • Why There’s Something and Not Nothing — Washington Post
  • Exotic matter — Princeton
  • 365 Days of Astronomy “Tell Me a Story … On Asteroid” contest
  • Overfed Black Holes Shut down on Star Formation — NASA
  • Transcript

    Transcription services provided by: GMR Transcription

    Female Speaker 1: This episode of Astronomy Cast is brought to you by Swinburne Astronomy Online, the world’s longest running online astronomy degree program. Visit Astronomy dot S-W-I-N dot E-D-U dot A-U for more information.

    Fraser Cain: All right, so welcome to Astronomy Cast live from Dragon Con.

    So my name is Fraser Cain. I’m the publisher of Universe Today and with me, as always, is Dr. Pamela Gay, professor at Southern Illinois University Edwardsville and the director of Cosmo Quest.

    And so today we’ve got a few victims here that we’re going to be sort of adding to the podcast and the topic – let me just see if I got this right here – the tough questions of space science. What I think it really should be is the tough questions from Fraser.

    So there’s a bunch of questions that Pamela’s often unwilling to answer or she gives me just this really quick answer, which is I don’t know. We don’t know. How could we know? So we got some fresh meat here tonight. And what I thought we would do is we would ask some of these questions to some of the other people. If Pamela wants to chime in, that would be great.

    So I thought I would sort of set the tone for the evening, but go for about 20 minutes, half an hour or so with some of these questions and then when I’ve run out, but I won’t, then I thought I would give you guys a chance to ask some questions. Here’s the deal. Here’s the game. They got to be awful, just horrible, tough.

    Pamela Gay: And by horrible and awful what he actually means is these must be the most difficult questions you can think of, the types of questions that should we be able to answer them might garner us Nobel Prizes because he hates us that much.

    Fraser Cain: Yeah, it’s Nobel Prizes for everybody.

    Female Speaker 1: This episode of Astronomy Cast is brought to you by 8th Light Inc. 8th Light is an agile software development company. They craft beautiful applications that are durable and reliable. 8th Light provides disciplined software leadership on demand and shares its expertise to make your project better. For more information, visit them online at www.8thlight.com. Just remember, that’s W-W-W dot the digit 8 T-H-L-I-G-H-T dot com. Drop them a note. 8th Light, software is their craft.

    Fraser Cain: All right, so I just want to just start. We’ll start with an easy one here. All right. All right. So Les –

    Les: Oh great.

    Fraser Cain: Okay. Star Trek transporter.

    Les: Okay.

    Fraser Cain: Is it a transportation device or a suicide booth?

    Les: Both. I mean, it’s really both.

    Fraser Cain: Explain your answer.

    Les: Oh, yeah, yeah, the mic. Yeah, I think it’s really both because the way I understand it from Star Trek lore is that it disassembles the atoms in your body, right, and recreates them somewhere else. And disassembling the atoms in my body kind of sounds like killing me. So I’ve always assumed that it was some kind of deconstruction of everyone, especially McCoy, and reassembling them out of whatever is localized somewhere else. Although sometimes in the show, it’s not known for its consistency technically, I think, they talk about rematerializing in empty space which shoots my theory all to heck. So I don’t know about that.

    Pamela Gay: You actually just framed that in a way that I haven’t heard before because normally the assumption is you disassemble the person, you then transport those atoms somewhere else and reassemble them, which leads to a vacuum in one place and too many atoms in the other place and people finagle this with well maybe you’re swapping the atoms between the locations. But if you’re actually disassembling them here and just letting all of my bits and pieces sort of vaporize or do whatever, you remove the suddenly causing vacuum issues.

    Les: I’m glad to be of help.

    Male Speaker 1: Disassemble, disassemble.

    Fraser Cain: Does anyone else have an opinion that differs?

    Erin: No.

    Fraser Cain: No, you’re all good with this?

    Les: I have no idea what I’m talking about, but we’ll take it.

    Fraser Cain: All right, so Scott.

    Scott: Yes.

    Fraser Cain: How do you pronounce the 7th planet?

    Multiple Speakers: Ooh.

    Scott: I was told that there would be no Uranus jokes here.

    Fraser Cain: Is that your final answer? All right. All right, Uranus.

    Scott: Uranus [inaudible] [00:04:39].

    Fraser Cain: Uranus is the Greek pronunciation. All right. All right. So Erin you work on black holes?

    Roy: I work on black holes.

    Fraser Cain: You work on black holes. You both – well, Roy, you can have this one.

    Roy: Okay.

    Fraser Cain: So what does a black hole look like inside the event horizon? No, you can’t say we don’t know.

    Roy: Okay, so it depends on the mass of the black hole because – well, the time in which you would be able to view inside the event horizon depends on the mass of the black hole. So you get this super massive black hole, so you got a really big event horizon, what it looks like inside is that you would see what ever entered the event horizon before you, essentially as it looked before it entered and you would still see the event horizon before you even though you were inside of it.

    Fraser Cain: Whoa, what?

    Pamela Gay: So you’re avoiding the question quite masterfully. I know this because if it’s me, he doesn’t let me get away with that answer. So while I understand if you fly past the event horizon, you don’t see any noticeable change at that point in time, but should you keep going and see that blob o mass that is of sufficient density, do you trigger the event horizon to exist? What does the blob o event horizon causing mass look like?


    Pamela Gay: So it was initially meant for me, but he’s the black hole expert. I would say that his answer was perfectly right and the reason for that is because the light is falling in and it’s not reflecting back out because it can’t. The gravity’s too high.

    Fraser Cain: But is it a sort of a physical size? Does it stop compressing at a certain point or does it just keep shrinking?

    Pamela Gay: I suppose if you’re traveling into a black hole, you’ve got bigger things to worry about, but effectively it keeps going to a point in our reference frame.

    Fraser Cain: So it’s probably infinitely small.

    Pamela Gay: Effectively, yeah, but can you – do you have a better answer for that? I just mean with our concept of space time and our reference frame, if you think of us as falling over that event horizon into there, you’re going to travel effectively forever until you’re a point with all the stuff that has become a point.

    Roy: Well, I think we all know from the 1979 Disney movie The Black Hole, which I think was a documentary, that it looks like you’re entering a stained glass window of a cathedral.

    Fraser Cain: Okay.

    Roy: Unless you’re evil –


    Fraser Cain: I’ll accept that answer for sure. Yeah, all right. So Les –

    Les: Oh joy, here we go.

    Fraser Cain: So – no, this one’s easy. This one’s easy. This is right up your alley. Will we ever build a space elevator?

    Les: Will we ever build a space elevator? I don’t believe we will because I don’t believe we will practically want a space elevator.

    Fraser Cain: Really?

    Les: And I will be deemed a heretic from a large part of the space community for saying that. A space elevator goes all the way out to geosynchronous orbit and that’s 10s of thousands of miles out and it’s at the equator. And that means that everything in its orbit is going to cross the plain that the space elevator is located in, everything. And so every time a satellite or a piece of junk, and there are 500,000 pieces of junk in earth orbit that are the size of a pea or larger, circle the earth they’re going to have a chance at hitting the space elevator at orbital velocity. And I don’t care what it’s made out of it, that’s going to damage the space elevator, right?

    So if we’re going to build a space elevator and have it be practical, we have to get rid of all of the junk and we have to stop flying all satellites in earth orbit because all of them will have a small chance every time they circle the planet of hitting the space elevator. So if we decide we want to get rid of all this stuff and we can clean up all the junk, then yes, we might build a space elevator.

    Pamela Gay: We could have other geosynchronous satellites.

    Les: Yes, we could. That’s it, but nothing in low earth orbit.

    Pamela Gay: Nothing in low earth orbit, so we’d be allowed weather satellites and we’d be allowed communication satellites and anything we’re bored enough to put in geosynchronous.

    Les: That’s right. That’s exactly right. So practically speaking, even if all the miracles happen with materials and the construction, it’s a very practical problem. Do you really want this thing?

    Male Speaker 2: So assuming that you can have a space elevator, would it be faster than the elevators in the Hilton?

    Les: Probably, yes.

    Pamela Gay: Okay, let’s flip it because the most recent thing I heard is we’re not looking at an earth space elevator, we’re looking at a lunar space elevator.

    Les: I’m an advocate of space tethers and using long cables for moving things around in space. I still wouldn’t put an elevator on the moon. I’d use a rotating tether so that you could rapidly get things from the surface of the planet – of the moon out into space. So I think yes, that might be more likely than one on the earth, although I have a question about how you would anchor and what the definition is of geostationary orbit at the moon and how you practically do that.

    Fraser Cain: Yeah, so Les can you explain a bit about what the tether is?

    Les: Oh sure, a tether. A tether is a long conducting cable or a long wire in space. We’ve flown several that are about 20 kilometers long and their idea is for being able to use these long cables that really aren’t that big. I mean, think of electrical wire. You could make them out of cabling about that size. That could be slowly rotating in space and used to move payloads between orbits.

    Fraser Cain: Right. Scott, how old are Saturn’s rings?

    Scott: Depends on the week. One week I might see an article that says oh, they’re quite young. And then another week I might see an article that says they’re quite old and I think it’s because you’re looking at different aspects of the rings. There’s the massive rings themselves, which may be quite old, but then there is the – all the collisions that happen within the rings. All the meteorites that hit the rings which makes them look quite young. So the short answer is really no one knows.

    Pamela Gay: Well, and there’s also the difficulty that we know the rings are being restocked, I guess is the best way to put it, from the ice geysers. And so you have some particles that are ancient, some that are new and so you have a continuum of ages across the particles.

    Fraser Cain: That was a great answer, Pamela and that has earned you a question. So Pamela, we look out into the universe and we see sort of the edge views of the universe, 13.8 billion light years, but that’s actually 47 billion light years away, is the universe finite? Is it a little bit bigger than that or much bigger than that or is it infinite, just goes on forever? How could we know?

    Pamela Gay: So we can’t actually get at the is it finite or infinite until we have better measurements of the cosmic microwave background radiation. And if it is finite, we have already reduced it down to knowing that we live in only a few percent of the observable universe and this is because when things emit light, they emit light in all directions. And so since space is curved, it’s one of those unfortunate realities we deal with, light that’s given off in all directions is basically going to – if you emit it out your eyes because you’re wearing Starlord’s helmet, it’s going to fly through space and hit you in the back of the head eventually.

    Well, when we look out at the cosmic microwave background, this means that some of the features we see on one side of the sky, we should also see on the other side of the sky if there has been enough time and everything else and the universe is finite, then the light will wrap around.

    Now, the way the finite part comes in is you actually have to be able to go all the way around and if it’s infinite, there’s no going all the way around because you just never get there from here. Now, as we keep looking more and more in detail at the cosmic microwave background, we have blank data now. We’re still just not finding any reflections. So that percentage of the universe that we take up keeps getting smaller and smaller if the universe is finite. And people who are hoping for an infinite universe, keep brooding harder and harder and with greater enthusiasm.

    Fraser Cain: So you could see better instruments doing a better measurement of the cosmic microwave background and get to this point where it’s essentially infinite because the measurement is so precise that it just keeps expanding out the size of the finite universe [inaudible] [00:14:04].

    Pamela Gay: We start to run into resolution issues where you can’t say the universe is finite just because we don’t have enough resolution on the galaxy size even to say that. But we do get to the point where if we see the reflection we can say yes, yes, it is finite. But infinite is you just can’t get there from here.

    Les: Sort of sounds like Xena. He was confused.

    Fraser Cain: Was he? Erin, question for you. So what came first, the supermassive black holes that we find at the heart of galaxies or the galaxies themselves?

    Pamela Gay: Do you want to take this?

    Roy: Go for it.

    Erin: He just physically moved away from me.

    Fraser Cain: This is awesome.

    Erin: Yeah. I don’t know and that’s not an acceptable answer for this podcast, so I would say that given my understanding in terms of the gravitational wave searches and the things that they’re looking for that that’s one of the things they’re trying to figure out, is sort of how those black supermassive black holes grow and develop and where they might have started from because they might have started as solar mass black holes way, way back in the day and then over time accumulated more and more mass and grew and then sort of became more of a center point in an old galaxy that then collided with another galaxy that then collided with another black hole in that galaxy and it just continued to get bigger and bigger and bigger.

    But there needs to be a lot more searches done to be able to say definitively where they came from because it is a chicken and the egg type thing.

    Fraser Cain: So what could astronomers be looking for that could help kind of get to the bottom of that chicken or the egg scenario?

    Erin: The rate of supermassive black hole collisions at different distances. So how often they might have collided further back in time. Rates of collisions is always an interesting thing for astronomers to figure out the evolution of the universe. So that’s something that will give us a good indication of how often things happen and then if that starts to become a causal effect. Is that an okay answer? That was a hard question.

    Pamela Gay: I’m going to elaborate on this.

    Fraser Cain: Yeah.

    Pamela Gay: So there’s been some really fascinating research in the past year that shows that the answer is both. We used to think that galaxies formed either through the accretion is the fancy, schmancy word we use. The reality is things smooshing into each other where you take smaller galaxies and you build up in to bigger and bigger galaxies.

    Now, the problem is the further back in time we look, which means we look at things further away and their light has been traveling longer to get to us. No matter how far back we look we keep finding giant galaxies that shouldn’t have had time to grow out of the accumulation of smaller systems. So it’s now looking like some of the largest over densities mass after the Big Bang, places that had the greatest pile of material after the Big Bang occurred, these places are essentially being the nuclei of massive galaxies that formed in a I’m just going to form out of the material right here and forget this whole accumulation of smaller bodies.

    And there’s theories that show you can actually form the supermassive black holes using turbulent flow in these early models. There’s all sorts of awesome stuff involved in this. It’s ongoing research. We don’t know if the turbulent flow model for building supermassive black holes is true or not. James Webb’s space telescope will get us closer to understanding if it’s true or not. We do know there are giant galaxies in the early part of the universe that are best explained by saying these suckers just formed big.

    Now, there are also the tiny galaxies forming in irregular structures that look like smooshed dead bugs that do gravitationally bond with one another to build up into larger and larger systems. And we know that the size of a supermassive black hole is related to the size of the galaxies within. So as those baby galaxies merge together, you end up with mergers of the supermassive black holes to go from baby supermassive black holes to massive supermassive black holes.

    Fraser Cain: All right. That’s great. Les – so Les, will we ever move faster than the speed of light?

    Les: I’ll give you – within what we know about how the universe works right now, no. Okay, it appears that the laws of nature are written such that it will prevent us from doing that. But I know better than to say something is impossible because our understanding of the universe is absolutely incomplete. There are lots of unanswered questions in physics. There are lots of really interesting experiments out there that are being performed that you have to scratch your head and say well, what if?

    So I would be foolish to say it’s going to be impossible and we’ll never do it, but I will say we’ll have to have an understanding of the way the universe works that different than our current understanding before we’ll be able to do that, which really stinks, by the way because I would love for us to be able to find that work drive and just go. But it looks like it’s going to be a slow boat to another star right now.

    Fraser Cain: Right. Roy, how’s your general relativity?

    Roy: Okay.

    Fraser Cain: So let’s say we take a spaceship and we go really, really fast and we take that spaceship so fast that it’s mass increased, if I understand relativity correctly, right? So would that spaceship turn into a black hole if it goes fast enough?

    Pamela Gay: And for background material on this, when he first asked me this I said, “I don’t bleeping know” and broke two theoretical physicists.

    Fraser Cain: Let him answer. He’s on the spot.

    Roy: Wow. Hmm. I don’t know.

    Fraser Cain: All right.

    Pamela Gay: Not an acceptable answer.

    Roy: I think all you all have given one of them.

    Fraser Cain: Yeah, we actually did hammer this one out, I think. Did we get an answer on this one?

    Pamela Gay: No.

    Fraser Cain: No, we didn’t.

    Pamela Gay: The theoretical physicist that was working the hardest in figuring this out one day came into my office and said he was retiring.

    Fraser Cain: If anyone has an answer that would be great. I’m still waiting for that one. I’ll put that on my future list. All right.

    Roy: Next week’s show.

    Fraser Cain: That will be next week’s show. All right, I got an easy one for Scott. So Scott, what’s the best place other than earth, obviously, to look for life in the solar system?

    Scott: Well, okay. So scientists have been looking for life in what’s called the habitable zone. And traditionally that’s been defined as the region where water exists in liquid form. So if you’re too close to the sun, you’re in gaseous form and if you’re too far you’re in ice. And so there’s this magic zone that earth just happens to be in, Mars just out of that zone, Venus just out.

    But what we’ve been learning with Cassini and even subsequent observations with Europa is that there is a lot of moons out there where there’s enough tidal energy to heat the interior to the moons and even though they have icy crusts, they could have a liquid region, oceans basically. And we think that Titan, Enceladus, Europa are good places to look for this life. And you want to look for things that – you want to look for molecules and [inaudible] [00:22:45] that would be a key ingredient to live. And you need the energy source. Well, if you have enough tidal force, you have the energy to be there.

    Fraser Cain: So pick one.

    Scott: Out of all the moons, there’s a lot of focus on Europa and Enceladus, which are good places to look for liquid water and we do know that Enceladus has a lot of key molecules, but I think Titan is the place to go.

    Fraser Cain: Really?

    Scott: Yes. I think it’s because we know there’s a liquid ocean underneath. Cassini has detected that. And it has just the right combination of ingredients. It has a lot of nitrogen; a lot of methane from which hydrocarbons can be formed and you have water there from which you could get oxygen. And if you combine things in the right way, you might just get that amino acid that might form protein, etc.

    Fraser Cain: That’s interesting. All right, let me see what else I got here. Okay, so Les, have you ever heard of the Fermi Paradox?

    Les: I’ve lost a little sleep over it.

    Fraser Cain: Okay, perfect. Perfect. So what do you think is the best explanation of the Fermi event? For those who aren’t aware of the Fermi Paradox, I have also lost a lot of sleep over this. And this is this idea that if the universe is old and life – we know on here that life formed as quickly as it could possibly have formed that there’s nothing in the laws of physic that would stop aliens from essentially colonizing the entire galaxy within a couple of million years. So where are all the aliens? So what do you feel is the best explanation for why we see no evidence of aliens?

    Les: Unfortunately the pessimist in me tends to believe that intelligent [inaudible] [00:24:49] life is probably somehow self-limiting in that we somehow managed to reach a point where we’re either no longer interested in settling the stars and going out. We all live in some virtual reality simulation and we just lose interest in that or we destroy ourselves.

    Now, that’s the pessimist in me. I know you’re going to press me to one answer, but I have to give two to begin with. The optimist in me says we’re the first. Okay? So it’s our universe to take or lose. But unfortunately I think the pessimist in me is what causes me to lose sleep because there are so many things that could cause a collapse or could be catastrophic and we’ve avoided some of them already just barely. I’m thinking nuclear war and what happened in the Cuban Missile Crisis and all that. So I tend to be a little bit pessimistic. I don’t know what that lifetime of civilizations might be. I hope it’s a good, long time and we can get a good, long run.

    Fraser Cain: Okay, so you’re talking about something that’s known as the Great Filter. And so this is this idea that there is something that prevents all civilization from reaching to become a star faring civilization. So Erin, you had some ideas on maybe what this would be?

    Erin: Well, I heard an interesting theory that it’s gamma ray bursts. That gamma ray burst happen at pretty much – because the idea is if a gamma ray bursts happens close enough to you and it’s beamed to you it can be quite catastrophic to that world. And they – one of the mass extinctions of earth might have been from a gamma ray burst. And the idea is that they happen infrequently, but frequently enough that it prevents – that it wipes out a civilization from becoming able to travel to other lands or stars, which is scary.

    Pamela Gay: So there was actually what to me at least was an idea that I never thought of before, in Calculating God by Robert Sawyer and the idea is that every – it’s just a theory related to God that’s just a different part of the story. But the idea within this book is spacefaring races at the level of being able to build generational spacecraft evolve, but fairly infrequently and the next step that they go on is to become so sufficiently advanced that they’re able to put their consciousness into computers. And so these civilizations stop being biological and instead become supercomputer based, bury their supercomputers, make their world to pure barren. So if you go out amongst the stars you find a lot of worlds that appear to be completely uninhabited, but actually have in geologically stable places vast civilizations essentially living on and on and on forever in this essentially cyber reality. And that was just an interesting Option C that lifeforms would rather live forever in cyber form than colonize our entire galaxy.

    Les: So Cylons.

    Pamela Gay: Yes.

    Fraser Cain: So then, Roy, to sort of follow onto that question, do you think we’re living in a simulation right now?

    Roy: No.

    Fraser Cain: And why? Could we tell the difference?

    Roy: No, I don’t think we could, but I don’t think that we are.

    Fraser Cain: Well, why not?

    Roy: I’m more optimistic than that, I guess.

    Fraser Cain: Why?

    Roy: It’s very discomforting to think we’re living in a simulation, isn’t it?

    Fraser Cain: Okay. Well, absolutely.

    Roy: Also, if we’re living in a simulation, it’s a really crappy one because we all die and if we’re living in a simulation couldn’t we make it so that we get to live forever? Can’t we live in this simulation where we can live underground?

    Pamela Gay: My theory is that we’re somebody’s game of Sims City and while they’re pretty good, they’re not that imaginative.

    Roy: No, I think that’s compelling, which is that if we were living in a simulation it would be better. So –

    Fraser Cain: Okay, great. Let’s see. Am I running out? Okay, so Pamela, what happened before the Big Bang?

    Pamela Gay: No.

    Fraser Cain: Would anybody else like to answer this question?

    Erin: Yeah, I’ll give it a go. My – this is so bordering on science fiction, so bear with me.

    Fraser Cain: That’s fine. It makes it more awesome.

    Erin: Yeah, exactly, which is why I’m going to mention it because every time I have an opportunity I try to. I love what is sometimes referred to as the Dripping Universe Theory where our universe was born out of a supermassive black hole formation in another dimension and the mass that’s falling into that black hole is the dark energy that’s expanding our universe. That’s my favorite one.

    So the idea is that – our whole dimension space/time reference doesn’t exist until that supermassive black hole forms and starts to expand. It’s just awesome.

    Pamela Gay: So I’m going to play Fraser because he wouldn’t let me get away with that. What came before that supermassive black hole?

    Erin: Another universe with a supermassive black hole.

    Pamela Gay: So you’re telling me it supermassive black holes all the way down.

    Erin: Yes. Well, we like a concept that we call infinity. And I’m willing to pull the infinity card.

    Pamela Gay: So along with post turtles supporting the universe, we know have post supermassive – okay.

    Erin: Yeah. Let’s go with that. I’m all right with that.

    Fraser Cain: All right. So I’ve got one more. I was going to give this one to Pamela, but – so Pamela, why is there something and not nothing?

    Pamela Gay: Well, once upon a time there was this little, tiny, extraordinarily dense bit of matter that decided it needed to expand out. And we had a big bang. And the something came out of that infinitesimally little tiny, very dense something that became a bigger something.

    Fraser Cain: All right. We’ll let you get by with that one for today. So anyone on the panel now, do you think wormholes are possible? Anyone on the panel feel free to jump in. I’m not sure who’s got expertise in this.

    Erin: Are you asking stable or exist?

    Fraser Cain: Both. Either a stable wormhole is possible and then do they exist?

    Les: Definitely in my yard.

    Scott: I think stable wormholes are possible, although I don’t have a good reason to think that. I don’t think traversable wormholes are possible. And there’s a lot of good theory to demonstrate that traversable wormholes are not possible.

    Pamela Gay: So from what I understand of the mass about wormholes, anytime matter enters them they collapse and we have this annoying cosmic microwave background and energy is the same thing as mass, how would you get a wormhole to exist longer than the photon rate from the cosmic microwave background?

    Scott: Exotic matter.

    Pamela Gay: That is a cheat.

    Fraser Cain: I’ll let it pass, exotic. Tell me more about this exotic matter.

    Erin: Dark and dark.


    Fraser Cain: Dark red matter energy. All right, so we got that, got that. Good, okay. So I’ve sort of hammered through my questions and I wanted to give folks out there in the audience a chance.

    Pamela Gay: [Inaudible] [00:33:06].

    Fraser Cain: Oh, sure, yeah.

    Pamela Gay: I do have one sad bit of news. The last podcast that we recorded and put into our feed was recorded at Volta Con with PG Holyfield as the cohost. And while we did this recording, we talked about doing a competition on short stories involving asteroid science. We wanted a collection of science fiction stories and we’d be recording the best for use on Space Stories, part of 365 Days of Astronomy. And PG was doing this with me and was going to be writing a planetarium show with me on asteroids.

    Unfortunately he passed away on August 20th. Because of that we haven’t posted the contest yet. We have taken submissions and I’m going to extend the deadline for the submissions and we’re going to do this in honor of PG Holyfield. So any of you out there, all of the details are up on 365 Days of Astronomy. We will link to that in the show notes. And we’re looking for submissions to help explain asteroid science through science fiction. And the best ones will have my voice reading them and turning them into audio dramas.

    Fraser Cain: All right, go ahead.

    Female Speaker 2: You all have already talked about black hole some and how everything basically that gets caught by them gets sucked down into a tiny infinitesimally dense, infinitesimally small speck of matter. Could one of the these – could a speck of matter that size have – could a black hole basically have gotten full and the forces that repel atoms and particles eventually overwhelm the gravitational force and that explosion caused the Big Bang?

    Fraser Cain: Right. So could a black hole create another Big Bang? Black hole people?

    Roy: Isn’t that what you just told us happened? All the way down.

    Erin: Yeah, all the way down. I mean, your question, I guess, kind of – are you – you can just nod and I’ll say it in here, but do you mean in this dimension that it would basically be a crunch and then another Big Bang? Yeah, that’s a little bit different, so that would be a black hole kind of slowly started to eat everything up.

    But a common and understandable misconception of black holes is that they’re not really vacuums. If our sun as its mass was a black hole, we’d be fine because the event horizon is there and it doesn’t sort of suck stuff in. It does gain in mass and gain in size, but not in a super active vacuuming sort of way. Did that –

    Fraser Cain: No, but I think I know what she’s getting at, so allow me to make this harder. So I mean, I guess the point is in a black hole you’ve got an enormous amount of mass and density under pressure, tons of mass compressed down and that’s very similar to the situation that was the singularity that started out the Big Bang of the universe. And so could you get a situation where so much material has gathered together that you’ve essentially got the same conditions for the Big Bang and therefore is that maybe how the Big Bang happened?

    Roy: I think you could only do that if we lived in a closed universe. If the universe were going to eventually collapse back on itself, if we’re not expanding and accelerating that expansion instead of contracting, I think maybe you could end up with that condition again and that was what a lot of people thought might be the case. If we lived in a closed universe then maybe we live in a cyclical universe. But I think that’s the only way you could get that condition again. And since we don’t live in that universe, I don’t think you could have it.

    Fraser Cain: But isn’t there one thing that’s kind of missing from the recipe, which is space time itself. A black hole is – here I am answering an awful question. What’s happened to me? That a black hole itself is inside space time while the Big Bang had space time as part of it when it expanded.

    Erin: So the way that you described it is that that’s kind of the foundation for that Dripping Universe theory that basically it reaches a supercritical point at a very high mass and then it effectively tears through to another dimension, which is – I mean it’s so – but that’s the idea is that it wouldn’t kind of reflect or explode back out into our universe, given those dynamics, but something else would happen with that.

    Pamela Gay: So I think what our poor innocent questioner was actually trying to get at also was we know that you can only make atoms so large because it eventually the forces that hold together nuclei lose to the electromagnetic force and things start repelling each other back apart again. But with black holes is there anything that would cause them to eventually, like the largest atoms, start falling back apart again?

    Fraser Cain: Can you overfeed a black hole?

    Roy: I don’t think so.

    Erin: I don’t think so.

    Roy: No. No, so you could never overfeed a black hole and, in fact, we probably all heard of hawking radiation, right? This is the situation that black holes will evaporate over time and the more you overfeed your black hole, the slower the hawking radiation is going to happen, right?

    Scott: Yeah and if what you’re feeding the black hole is normal matter, there’s a limit to how fast you can feed it as well before the matter itself will push itself apart before it can get into the black hole.

    Fraser Cain: Did that answer your question? Yeah?

    Female Speaker 2: I’m satisfied.

    Fraser Cain: Okay. You’re hoping black hole big bang. Yeah, no. Sorry.

    Male Speaker 3: In reference to the question you asked earlier about the spaceship traveling close to the speed of light and then becoming a black hole, does the change in mass occur to the observer on the ship and if so – and if not, how does it affect how you think about the question?

    Pamela Gay: And this is why I broke a theoretical physicist. So in the perspective of the moving – the dude on the spacecraft, everything stays the same. He does not perceive all of the relativistic stretching, the change in momentum. All of that is not in his reality. And yet to an outside observer, there is a change in momentum that is often discussed as a change in mass. And so the question then becomes, and the breaking of the theoretical physicist occurs, can that thing with this increased momentum essentially have all of the observable aspects of a black hole even though the observer doesn’t perceive any of that.

    Male Speaker 3: Would that mean that the observer would be acting as a black hole until he slowed down?

    Pamela Gay: That is the question that eventually led to the answer of there isn’t enough mass in the universe to go that fast.

    Roy: Yeah, that was the gist, is that it would act like a black hole, but it wouldn’t actually be a black hole.

    Male Speaker 3: Thank you.

    Male Speaker 4: So pretty much, not the same question, but the same topic. Suppose you did turn into a black hole, I mean, does that mean you’d have the black hole flying through space at the speed of light? And –

    Fraser Cain: Well, nothing can move at the speed of light.

    Male Speaker 4: Well, at or near the speed of light.

    Fraser Cain: Near the speed of light.

    Male Speaker 4: Would turning into a black hole not slow it down?

    Pamela Gay: So the issue becomes as something goes faster and faster and faster, its momentum increases and this is usually discussed as its mass increasing. And as it accelerates, its mass would eventually reach the point where given how big or small the object is, but it’s getting stretched as it grows making the math harder. As it gets stretched as it grows, does it reach the point that in its short axis, this is where the math gets ugly and I’m sorry I’m now going into this and breaking all of you. So it’s stretching along the direction that it’s moving. It’s not stretching along the other direction. So the question is on the other direction are you close enough to the center of mass that you’ll end up with an event horizon. And then it becomes a matter of you have something with an event horizon potentially on one axis only because it’s stretching in the other axis, that is traveling at some really big ass speed through the universe.

    Male Speaker 4: But if it was – if it had an event horizon on one axis, would it possibly pull the other axis into it?

    Pamela Gay: No, that’s where it gets all screwed up and this is where the math – this is where the math defeated me soundly and I went to someone who likes math and doesn’t cry over it. And, as I said, he retired.

    Fraser Cain: We’d love anyone to pick up the math and keep grinding on the math.

    Male Speaker 5: So I have a question to the panel, what about if we have the math wrong? We know that relativity does not mesh with quantum mechanics and they predict different things and we know that they don’t mesh.

    Fraser Cain: Yeah, I don’t know.

    Male Speaker 5: What’s the answer to that?

    Fraser Cain: I don’t know.

    Erin: So I’m not speaking on behalf of gravitation wave searches or the LIGO collaboration when I say this, but the idea is in the next – so LIGO are the ground based – earth based detectors that are trying to directly detect gravitational waves, which are the stretching of general relativity and space time. And they are currently being upgraded and are on schedule to be online next year. That’s public knowledge. And the upgrade that they’ve done has been done and with our current understanding of astrophysics, they will be able to detect events at a rate of about one per year at the lowest limit starting in about 2018 or 2020. Come 2025 and they’ve not seen anything, that’s currently the cutoff for saying maybe we’ve got it wrong and that will force the rethink of general relativity because our current rates say in our understanding there’s no reason why we shouldn’t be detecting gravitation –


    Fraser Cain: But gravitational waves have been seen detected indirectly with –

    Erin: Yeah, absolutely. Every –

    Fraser Cain: With rotating pulsars and things like that.

    Erin: Exactly. Every indirect detection of – every indirect detection that’s been made shows that gravitational waves and general relativity exist and there’s no reason not to think so. The question is if we got it wrong, that will start to become a more serious question once gravitational waves are not – if gravitational waves are not detected.

    Fraser Cain: So if gravitational waves are not detected and that becomes a pretty and important question.

    Erin: Very serious question for good reason.

    Pamela Gay: With the caveat that I remember hearing someone make almost the exact same statement almost five years after I was supposed to graduate undergraduate and I graduated undergraduate in ’96.

    Erin: This is why – yes, you’re absolutely right. And that is – this is an issue that happens with gravitational waves; however, the LIGO detectors are on schedule to be at a sensitivity where the rate is so good previously, it was kind of like supernova really close, we’ll detect them type thing.

    Pamela Gay: And the caveats that I worry about are more related to – I would not be surprised if we discovered new geophysics, where we discovered lower grade tectonics, more planetary vibrations and we have great geophysics coming out of LIGO and that would not be cool, but it would give relativity longer to live.

    Erin: Absolutely. And this why I’m saying I’m not saying 2025 no detections because who knows what’s going to happen. We could learn more about – yeah, so when Pamela was talking about geophysics, the idea is these detectors are so sensitive they’re detecting changes in four kilometers down to one one-thousandth the size of an atom, stretching like that. And they pick up a lot of stuff. And –

    Fraser Cain: But a space based mission like LISA, which would put the constraints a lot tighter.

    Erin: Yeah, if anyone would fund it.

    Fraser Cain: If anyone would fund it. Did we all pitch in? Okay, all right.

    Male Speaker 6: All right. The universe is trying to kill you. What is your favorite way or your constant fear of how the universe is trying to kill you?

    Erin: Gamma ray bursts, no question.

    Fraser Cain: Yeah, gamma ray bursts, no question. Anyone else? How is the universe trying to kill you?

    Roy: I think near earth asteroids. I just think we’re not spending any money looking for them and we know there are thousands of earth crossing asteroids that are potentially hazardous, so I think that’s how we’re going to –

    Pamela Gay: LSST doesn’t cost anything?

    Roy: Yeah, it’s –

    Pamela Gay: We’re spending money on it. It has had the NASA and NSF funding and they have broken ground and started the mirrors. So we’re not currently working on it and they have closed shop on several good missions – not missions, several good ground based surveys.

    Roy: Right. LSST will be able to find some of these things. It’s observing [inaudible] [00:47:10]. It’s not designed for looking for near earth asteroids necessarily and it can only see part of the sky.

    Fraser Cain: Yeah, I mean, I think it’s two questions, right? Is the universe trying to kill us, humanity? And really it’s us trying to kill us, humanity. We’re working on ways to do that with global warming, things like that. I mean, global warming is not a problem for life on earth. Life on earth is going to be just fine. But global warming is really about us and about our being able to survive. So that – for me that’s the one that I think is going to be – those kinds of major climate changes that we’re going to make I think are what will probably do in our civilization.

    What’s going to kill life itself? I’m – the heating of the sun over the next 500 million to a billion years I think is the only thing that can take out life because life will find a way as we’ve heard. Anyone else got a way that they –?

    Les: I guess I’m more worried about what we’re going to do to ourselves also. I think on the timescale on what you’re talking about here with another asteroid collision or a gamma ray burst or the expansion of the sun and all that happening, the timescale is so large that if we continue to be a technological civilization, we’re going to get off planet and we’re going to go everywhere. And so I don’t know that that would kill – any of those would really wipe out humanity because I think we can do something about that if we’re here to make that choice. And so I’m more worried about what you’re talking about than I am the universe killing us.

    Pamela Gay: So I’m going to reflect on the fact that you said your favorite way, not the one that keeps you awake at night in honest terror. Friends don’t let friends read climate change papers. So my favorite way to destroy all life on the planet earth is a rogue black hole that happens to have a solar system crossing orbit that slowly but surely tears things out of their orbits in a collisions of worlds kind of way and we get sucked into an orbit that is highly elliptical so that we alternate between freezing and frying in a way that kills everything.

    Fraser Cain: All right, go ahead.

    Female Speaker 3: So what would it take to have a floating cloud sitting on Jupiter or Saturn? And as a follow up, what would you experience if you fell off of it?

    Fraser Cain: Okay, so I think you – but before we go on, I think you’ve picked the wrong planet because Venus, in the cloud tops of Venus you have earth pressure and earth temperature and breathable air is lifting gas. So you could literally make a floating city in the cloud tops of Venus and you could walk outside with a little bit of sulfuric acid out there –

    Les: That’s a detail.

    Fraser Cain: With some kind of breather and wash off the sulfuric acid every now and then, but – tomorrow. So I think that would be great. Now, if you fell off of either the one on Jupiter or Saturn or Venus as we described, what would happen to you?

    Les: Burn up.

    Fraser Cain: So would you burn up?

    Les: Okay, so if you’re going fast enough.

    Fraser Cain: You’re not going fast. You’re floating. You’re right on the –

    Les: Eventually you would be crushed because there’s no surface to fall onto and you keep falling and eventually your bones will be crushed. I mean, we’ve dropped probes into Jupiter’s atmosphere and we know it’s gotten crushed. I mean, personally I think the way to have a cloud city is to have the right propulsion system to build the cloud city on and the ever so minute puffs of air keeps it afloat.

    Pamela Gay: So I have to say that the way you get crushed is radically different across these three worlds. Saturn’s kind of awesome because the surface of its clouds – it’s density is such that at the surface of the clouds you’re the same weight that you are here on earth. Now, as you fall you’re going to get crushed by the gas pressure. Jupiter, same thing, you’re going to get crushed by the gas pressure. Venus is a mean planet. It’s going to acid coat you, eat away your skin, torture you and then you smoosh into its surface at extremely high velocities.

    So yeah, you might die along the way and if you don’t you hit the ground rather hard and then get crushed.

    Fraser Cain: Yeah in a recent video I suggested that we should just push Venus into the sun and be done with it.

    Go ahead.

    Male Speaker 7: Forgive my poor understanding, but as I understand it we are constantly being bathed in radiation of all sorts throughout the universe. What are the technical hurdles to being able to collect that energy out in space for a spaceship and to be able to power it, to be able to convert it into usable energy?

    Fraser Cain: That sounds like a Les question.

    Male Speaker 7: Or is it just a math question where there’s just not enough energy to do that?

    Les: Well, it depends on the scale, I think part of it. I mean, right now we have spacecraft that use solar panels to collect sunlight [inaudible] [00:52:24] and you can turn that – power your spacecraft or you can use that for propulsion by solar electric propulsion or something. You can use sunlight indirectly for moving around with a solar sail where you reflect sunlight and the momentum of the reflective light causes it to move. You can use planetary magnetospheres, like earth and Jupiter, to generate electricity with these long cables, these long tethers. So you could generate power and get propulsion from that.

    So it’s all a matter of scale. All of the things I’ve talked about here tend to take this diffuse energy, which is not very concentrated and you have to have large structures to collect it, to reflect it, to use it. Now, on scales larger than that, the energy’s very, very diffused. It’s in the outer solar system where the sunlight gets dim, the stellar magnetic field. I mean, all that probably in principle you could try to harvest, but you’d be on a very large scale to try to do that.

    Pamela Gay: Yeah, one of the problems is that people don’t really appreciate how low density that background radiation really is. When I was in graduate school, I did all of my imaging at McDonald Observatory, which has the misfortune of it basically carved into the granite with the 30 inches telescope I used for my research onto the mountain in a nice flat surface they created, which meant I was contending with the radiation coming up from the granite as well as the radiation coming down from space.

    The radiation from the granite was actually slightly higher flux. They didn’t let pregnant women observe on this telescope, which always disturbed me slightly. But I could take a 600 second exposure, a 10 minute exposure and with the one inch square chip I’d get a countable number of cosmic rays hitting the one inch chip over 10 minutes. So that’s not a whole lot of particles hitting my chip and I was sitting on top of granite that was influencing this.

    Now, you’re at in outer space, you don’t have that granite helping you out. As you move further away from the sun, the number of high energy particles you’re getting from the sun decreases, other high energy particles – well, you’re waiting for supernova to go off or waiting for cosmic rays, for a more distant supernova to go off, there’s just not enough. And some of these suckers just don’t like to be captured.

    The way solar sails work, which Les can talk about far more than I can, is they’re capturing a lot of the optic light, the photons coming off of the sun and those impart a push. Well, a gamma ray is just going to punch right through your solar sail quite happily, come out the other side most of the time. So if your x-rays and gamma rays are passing through, you’re infrared doesn’t have that much energy and there’s not a lot of cosmic rays with mass. You’re just going to kind of sit there going, “Huh, I need a breeze.”

    Male Speaker 7: Thank you.

    Fraser Cain: All right, well this is perfect timing –


    Les: But still –

    Fraser Cain: Oh, go ahead.

    Les: But still you should appreciate your magnetic field.

    Fraser Cain: Yeah. Oh yeah, no we got time for two more questions.

    Male Speaker 8: Yeah, I have a quick one. Do we know yet why there is not more antimatter in the universe? I think I’ve heard people say there was an initial imbalance between matter and antimatter which kind of seems like you’re assuming something just that’s convenient, that matches what you observe. So why aren’t there more antimatter galaxies and antimatter stars and things like that?


    Roy: Well, I don’t think we know the answer to that. Does anybody here think we know the answer to that? I don’t think we know. But if you believe in multiverse theory, one possibility is the antimatter is in another universe and so there are antimatter galaxies and antimatter stars and all that stuff in another universe to balance out the –

    Fraser Cain: So they’re just asking the exact opposite question over there.

    Roy: That’s exactly right.

    Fraser Cain: Yeah, go ahead.

    Male Speaker 9: Hey, thank you. So you asked a question earlier, I don’t remember the name.

    Fraser Cain: Les.

    Male Speaker 9: You asked Les what if we could travel faster than the speed of light or maybe you said at the speed of light.

    Fraser Cain: Faster.

    Male Speaker 9: Faster, okay. So I was really surprised when you asked that question because I was thinking if something like that happened, if we actually could travel than light, to what extent would that destroy our understanding of physics? How much of a crisis in physics would that be? How would we cope?

    Pamela Gay: So traveling through space at faster than the speed of light where you’re moving in a continuous I’m here, now I’m in the next place, now I’m in the next place, if you have mass there’s no way we know of to do that. People theorize about tactiums which have no mass and can somehow pull this off because they have no mass.

    Now, we do know that there are things with mass that appear to jump from one place to another through a theory called quantum tunneling and when I use theory, I mean this is one of the things that is most proven that we have in science. So when we start talking about getting something from A to B at faster than the speed of light, we’re looking at things that might not look too different except for the whole event horizon from the gates that they had in Buck Rogers from Stargate, from tesseracts, all of that sort of jumping through space rather than traveling through space, that doesn’t break the laws except for the fact we don’t know how to tunnel anything that big because the waveform reality of a human being, our ability to act like a wave is smaller than our body is and if our waveform is smaller than our body, how do we diffract?

    But we actually did a lot on one question show early on, so I’m going to say go hunting for where I babbled semi-consistently about this early on.

    Fraser Cain: All right, so we’re out of time. You got a question for me? Oh, I’m sorry we’re out of time.

    Female Speaker 4: It’s my track.

    Fraser Cain: It’s your track. Oh, please. We are at your disposal.

    Female Speaker 4: Okay. There are – how do I phrase this the best? There are – you have gravity, you have electromagnetic – my mouth isn’t working very well. You have the strong and weak nuclear force. All of those have their purposes and their strengths and their weaknesses in how they’re used. But gravity, I’ve always heard, is disproportionate to what it should be. Why?

    Erin: That’s a great question. So disproportionate you mean that it’s sort of weaker to some extent than all the –

    Female Speaker 4: It appears to be much weaker.

    Erin: Yes, yes. That’s okay.

    Female Speaker 4: Much weaker than it should be when you consider all of the different forces that are out there.

    Erin: Yes, okay. So just because my thesis has gravity in the title, this is now my curse.

    Fraser Cain: You’re our gravity specialist.

    Erin: Yes, apparently so. I mean, we know so little about gravity. This is an interesting thing. In terms of having particles that are associated with – because all the forces have associated particles. In gravity there’s a theoretical one called the graviton. I mean, when you look at the large scale of the universe, gravity is the kind of – I mean, I like to think of it as the overwhelming force because that’s why everything is shaped the way it is.

    Now, what’s there has to do with the other forces. I can’t tell you why gravity is as weak as it is. I wish I could. I think that’s something a lot of people wish they could say. But I do think we shouldn’t discount it as an interesting force to study.

    Female Speaker 4: I don’t mean to discount it in anyway. That is my whole question. Gravity affects absolutely everything in our universe, and yet it is considered the weakest of the forces. So why is that? There have been the theories that maybe most of gravity is an alternate universe, maybe it’s in a brain or whatever. So I guess what I’m really looking for are theories. What are you all’s theories about it?

    Erin: Exciting, fun things, yeah. I mean, I like the gravity is in another universe. That’s fun. And like I said, I think, especially when you look at the fine structure of the universe, that’s an amazing concept in terms of how gravity affects everything. So I don’t tend to see gravity as weak. I tend to just look at it as different scale. That’s how I rationalize it in my brain, the further out you fly, the bigger you see its effects. So I think of it as a pretty strong force and that was such a weak answer, but it’s 11:00 on Sunday at Dragon Con, so sorry. I’m really sorry. I’ll email you an answer.

    Female Speaker 4: I’m [inaudible] [01:02:07].

    Pamela Gay: So to take us momentarily where Fraser likes to take us, to the land that might be slightly fantasy driven, there are lots of papers, none of them accepted as this is the truth, that do put forward that gravity is perhaps rolled up into how we roll up all the other dimensions of our universe. We live in this X, Y, Z time for dimensional space, but we know there have to be additional dimensions for all the physics we use to actually work and maybe gravity is tied up in how we don’t experience those other dimensions.

    Now, my favorite not accepted by anyone that I know of theory that I ran across was well, Einstein said that gravity is the geometry of space. And so there was one lone paper I found and I found then others along these lines that contended that you have the electromagnetically strong and the weak forces that are a family of forces and then the massive objects via whatever, [inaudible] who knows, as I said, I haven’t found more papers on this idea, are able to warp space time so that gravity is the effect of this warping through other dimensions rather than an actual force that has a graviton that is undetectable.

    Fraser Cain: All right. So with that I think we’re out of time. I know it’s past 11:00 now, so I want to thank the entire panel for what is really cruel and unusual punishment. And literally seven years of pent of questions of while we’ve been doing Astronomy Cast. So when Rainn suggested the idea, now I had free reign, as it were, and she provided a whole team of willing victims. So thank you, all of you, for being good sports and answering these questions. I know they were awful and tough, but I think it’s great because what’s great is how we tackle these questions, that we don’t just kind of go oh, we don’t know, that we’ve got ideas, things intrigue us, it pushes this quest for knowledge out there and I think it’s really great.

    Pamela Gay: And this is our eight year anniversary.

    Fraser Cain: I know, so yeah. Astronomy Cast start at Dragon Con eight years ago. Yeah, was when we decided.

    Pamela Gay: We weren’t at Dragon Con, but it was Dragon Con weekend.

    Fraser Cain: That we decided to Astronomy Cast?

    Pamela Gay: Yeah.

    Fraser Gay: Yeah, yeah, yeah. So there you go. So thanks everyone for listening. Here’s to many more years.

    Thanks for listening to Astronomy Cast, a nonprofit resource provided by Astrosphere New Media Association, Fraser Cain and Dr. Pamela Gay. You can find show notes and transcripts for every episode at AstromonyCast.com. You can email us at info@astromonycast.com. Tweet us @AstromonyCast. Like us on Facebook or circle us on Google+.

    We record our show live on Google+ every Monday at 12:00 p.m. Pacific, 3:00 p.m. Eastern or 2000 Greenwich Meantime. If you miss the live event, you can always catch up over at CosmoQuest.org.

    If you enjoy Astronomy Cast, why not give us a donation. It helps us pay for bandwidth, transcripts and show notes. Just click the donate link in the website. All donations are tax deductible for U.S. residents.

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    4 Responses to Special Episode: Live from DragonCon 2014!

    1. aymar October 2, 2014 at 5:45 am #

      I just wonder what that poor pilot had ‘to pop’ in order to be unaware that his spacecraft is pulped into a black hole.

      Ovid, the whole thing is very simple. Fast moving virgins can always be transformed into bay trees given the right conditions.

      I suspect that Einstein would have been more careful with his thought experiments if somebody had pointed out that massless elevator cars can still have lead bottoms.

      One thing is certain, the unaccelerated observer (or twin) will not likewise be turned into a black hole. Silent sympathy can only go so far. I will insist on Mach in this point.

      I could not quite follow the part about stretching (no transcript yet). Maybe just another term for Lorentz Contraction.

    2. paul a. skillman March 16, 2015 at 2:42 am #

      Could Earth ever support rings?

    3. paul a. skillman March 16, 2015 at 2:44 am #

      Why can’t all the junk we have put up around the Earth form into rings?

    4. paul a. skillman March 16, 2015 at 2:55 am #

      Do all galaxies have black holes?

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