First Aired: February 11st, 2015
Status: Continuing
Network: PBS
Summary: Space Time explores the outer reaches of space, the craziness of astrophysics, the possibilities of sci-fi, and anything else you can think of beyond Planet Earth with our astrophysicist host - Matthew O’Dowd.
Next Episode:
New episode date is not available for now
Episode Statistics:
# of Episodes: 340
# of Episodes I watched: 0
# of Episodes I haven't watched: 340
Last Episode I watched: -
Episode Summaries
Select Season:
My Season Progress:
0 %
Season 2019
Episode 1: Are Dark Matter And Dark Energy The Same?
Air Date: January 10th, 2019
Summary: Astronomers are the worst at naming things. Dark energy AND dark matter? Who can remember which is which. But perhaps one astronomer has just fixed it, with a theory that says perhaps actually they are they same stuff.
Episode 2: Our Antimatter, Mirrored, Time-Reversed Universe
Air Date: January 17th, 2019
Summary: The foundations of quantum theory rests on its symmetries. For example, it should be impossible to distinguish our universe from one that is that is the perfect mirror opposite in charge, handedness, and the direction of time. But one by one these symmetries were found to be broken, threatening to break all of physics along with them.
Episode 3: The Crisis in Cosmology
Air Date: January 25th, 2019
Summary: The search for a single number - the hubble constant, which is the rate of expansion of our universe, has consumed astronomers for generations. Finally, two powerful and independent methods have refined its measurement to unprecedented precision. The only problem is that they don’t agree. This calls into question some of our most basic assumptions about the universe.
Episode 4: Perpetual Motion From Negative Mass?
Air Date: January 31st, 2019
Summary: Exotic matter – matter with negative mass - has long been the pipedream of science fiction writers, futurists, and certain rather. . . optimistic researchers. It’s the key to faster than light travel because it’s the only stuff that can curve space in the right way to hold open wormholes and construct warp fields. And if you can travel faster than light you can also travel backwards in time. We’ve been over those already. And we also recently covered a very new use for negative mass - as “dark fluid”, a proposed explanation for both dark matter and dark energy. That episode really got me thinking about the subtleties of negative mass and how it should really behave gravitationally. Turns out it’s complicated, and to answer it we really have to question the very definition of mass.
Episode 5: Sound Waves from the Beginning of Time
Air Date: February 8th, 2019
Summary: Invisible to the naked eye, our night sky is scattered with the 100s of billions of galaxies the fill the known universe. Like the stars, these galaxies form constellations – hidden patterns that echo the reverberations of matter and light in an epoch long before galaxies ever formed. These are the baryon acoustic oscillations, and they may hold the key to understanding the nature of dark energy.
Episode 6: Secrets of the Cosmic Microwave Background
Air Date: February 21st, 2019
Summary: Hook up an old antenna to your TV and scan between channels. The static buzz you hear is mostly due to the ambient radio produced by our noisy pre-galactic civilization. But around one percent of that buzz is something very different – it’s the cosmic microwave background radiation – the remnant of the heat-glow released when the hot, dense early universe became transparent for the first time. It sound likes random static, but that buzz contains an incredible wealth of hidden information. It holds the secrets of the universe’s fiery beginning.
Episode 7: The Impossibility of Perpetual Motion Machines
Air Date: March 7th, 2019
Summary: Bad ideas come and go in physics. But there’s one bit of nonsense that is perhaps more persistent than all others - the perpetual motion machine. No working perpetual motion machine has ever been experiment verified. All break the laws of thermodynamics. In fact, we classify based on WHICH law of thermodynamics they break. We have perpetual motion machines of the first kind - they violate energy conservation - they pump more energy out than they need to keep running. This includes most of the historical devices. Then there are machines of the second kind - they’re a bit more subtle in their wrongness because break the second law of thermodynamics - extracting energy by reversing entropy. Many modern “free-energy” devices fall into this category. Now the best modern designs are by you - answers to our recent challenge question, which we’ll get to at the end. But first let’s take a look at examples of what other people came up with - this’ll be a fun little journey through some pretty terrible science.
Episode 8: The Future of Space Tourism with Richard Branson
Air Date: March 14th, 2019
Summary: The private space-race has been on for a while now. The attention has been on Space-X and Blue Origin with their reusable rockets. But there’s one private space program that’s been doing things a little differently. Richard Branson’s Virgin Galactic isn’t building rockets at all – it’s building spaceships. And I got to sit down and talk to him about it.
Episode 9: Is Dark Energy Getting Stronger?
Air Date: March 21st, 2019
Summary: The power of Dark Energy may be increasing as the universe ages. Subtle clues are emerging that the accepted model for the nature of dark energy and dark matter may not be all that. We saw the first such clue recently in our recent episode on the Crisis in Cosmology. Today we’re doing a Space Time Journal Club to reveal another clue. We’re looking at a new paper in Nature Astronomy, “Cosmological constraints from the Hubble diagram of quasars at high redshifts” by Risaliti and Lusso. It hints that the cosmological constant may not be so constant after all. In fact it may be increasing. If this is true, then our prediction for the future of our universe looks VERY different, and may involve the entire universe tearing itself to shreds at the subatomic level in the Big Rip.
Episode 10: Could the Universe End by Tearing Apart Every Atom?
Air Date: March 29th, 2019
Summary: Of all the unlikely ends of the universe, the Big Rip has to be the most spectacular. Galaxies ripped to shreds, dogs and cat first living together, then tragically separated by the infinitely accelerating expansion of space on subatomic scales. Good thing it's not going to happen. Or is it?
Episode 11: The Edge of an Infinite Universe
Air Date: April 4th, 2019
Summary: Have you ever asked “what is beyond the edge of the universe?” And have you ever been told that an infinite universe that has no edge? You were told wrong. In a sense. We can define a boundary to an infinite universe, at least mathematically. And it turns out that boundary may be as real or even more real than the universe it contains.
Episode 12: The Holographic Universe Explained
Air Date: April 11st, 2019
Summary: We live in a universe with 3 dimensions of space and one of time. Up, down, left, right, forward, back, past, future. 3+1 dimensions. Or so our primitive Pleistocene-evolved brains find it useful to believe. And we cling to this intuition, even as physics shows us that this view of reality may be only a very narrow perception. One of the most startling possibilities is that our 3+1 dimensional universe may better described as resulting from a spacetime one dimension lower – like a hologram projected from a surface infinitely far away.
Episode 13: No Dark Matter = Proof of Dark Matter?
Air Date: April 25th, 2019
Summary: We’ve been failing to detect dark matter for decades. Finally, the latest failure to detect dark matter may have actually proved its existence. One of these is true - either most of the matter in the universe is invisible and formed of something not explained by modern particle physics OR our understanding of gravity is completely broken. The debate over which is true has raged for decades, but may finally have been resolved in an unlikely way - the proof that dark matter exists, and really is an exotic, unknown substance, may have come from the discovery of two galaxies that appear to have no dark matter at all. Today on Space Time Journal Club we’ll look at the papers that reveal this discovery.
Episode 14: The Real Science of the EHT Black Hole
Air Date: May 2nd, 2019
Summary: How do you take a picture of a black hole and what can we learn from it? Our first ever actual bona fide photo of a black hole, made by the Event Horizon Telescope and revealed to the world in a press conference on April 10th. Since then it’s got plenty of coverage, because … I mean look at it. It’s a freaking black hole. It’s black, it’s holey, it’s everything we hoped it would be. Now that the giddiness has subsided and I personally have stopped spending hours on end staring at a black spot, we can take a breath and actually look at the real science here and discuss exactly how a picture like this could be taken and what we can learn from it.
Episode 15: Why Quantum Computing Requires Quantum Cryptography
Air Date: May 10th, 2019
Summary: Quantum computing is cool, but you know what would be extra awesome - a quantum internet. In fact if we want the first we’ll need the latter. And the first step to the quantum internet is quantum cryptography.
Episode 17: The Alchemy of Neutron Star Collisions
Air Date: June 7th, 2019
Summary: Carl Sagan’s famous words - “We are star stuff” refers to a mind-blowing idea – that most atomic nuclei in our bodies were created in the nuclear furnace and the explosive deaths of stars that lived in the ancient universe. In recent years it’s become clear that the truth is even more mind-blowing. Many heavy elements - includes most precious metals - were produced in an even more spectacular event - the collision of neutron stars. In fact, according to a recent study most of the Earth’s supply of these elements was created in a single neutron star merger that took place near our Sun’s birth nebula 80 million years ago before Earth formed.
Episode 19: The Quasar from The Beginning of Time - STELLAR
Air Date: June 21st, 2019
Summary: Recently, the oldest quasar ever seen was discovered by the Gemini North telescope in Hawaii, the Magellan Telescopes at Las Campanas Observatory in Chile, as well as the Large Binocular Telescope in Arizona. In this first episode of the PBS DS mini-series, STELLAR, Matt travels to the top of Mauna Kea to visit the Gemini North telescope and see just how they found this ancient Quasar and it’s massive black hole.
Episode 20: Thorium and the Future of Nuclear Energy
Air Date: July 2nd, 2019
Summary: Energy too cheap to meter - that was the promise of nuclear power in the 1950s, at least according to Lewis Strauss chairman of the Atomic Energy Commission. That promise has not come to pass - but with some incredible new technologies, perhaps it still could. The question is - should it?
Episode 21: The Quantum Internet
Air Date: July 16th, 2019
Summary: When we finally have a quantum internet you’ll be able to simultaneously like and dislike this video. But we don’t. So I hope you like it. The world is widely regarded as being well and truly into the digital age, also called the information age. No longer are economies and industries solely characterised by the physical goods they produce, and in fact some of the largest companies in the world produce no physical goods at all - digital information is a commodity in its own right. As discussed in a previous episode, this worldwide digital economy is fundamentally reliant on certain cryptographic processes. Currently these processes work in the realm of classical cryptography, but one day soon this may not be enough and so quantum cryptographic methods and algorithms are being developed. However, it’s one thing to design a protocol, it’s something else entirely to build a system to support it. To understand what needs to be done we need to get to the foundations of quantum mechanics - we need to talk about quantum information theory.
Episode 23: Deciphering The Vast Scale of the Universe - STELLAR
Air Date: July 26th, 2019
Summary: One of the fundamental questions humanity has always asked is how big is our Universe? For much of human history, people believed that Planet Earth was the very center of the entire universe. And Earth is pretty big. But compared the rest of the universe, we are infinitesimally small.
Episode 24: What Caused the Big Bang?
Air Date: August 7th, 2019
Summary: Every astronomy textbook tells us that soon after the Big Bang, there was a period of exponentially accelerating expansion called cosmic inflation. In a tiny fraction of a second, inflationary expansion multiplied the size of the universe by a larger factor than in the following 13 and a half billion years of regular expansion. This story seems like a bit of a … stretch. Is there really any mechanism that could cause something like this to happen? What what we’re covering today – the real physics of cosmic inflation.
Episode 25: Exploring a HUGE Radio Telescope in VR 180
Air Date: August 13rd, 2019
Summary: How can you build a telescope that can see the entire night sky without moving its dish? Well in this special episode of Space Time we took a tour of the Arecibo Observatory with a VR 180 camera so you could explore the incredible ingenuity of Arecibo's giant spherical dish that allows it to reflect light from every spot on the sky in a symmetric way. We also talked to Dr. Abel Méndez about Exoplantes and Aliens!
Episode 26: What Happened Before the Big Bang?
Air Date: August 20th, 2019
Summary: We actually have a pretty good idea of what might have happened before the Big Bang. That is, as long as we define the Big Bang as the extremely hot, dense, rapidly expanding universe that is described by Einstein’s equations. That picture of the universe is very solid down to about a trillionth of a second after the supposed beginning of time. We can make good guesses down to about 10^-30th of a second. But before that?
Episode 27: How To Become an Astrophysicist + Challenge Question!
Air Date: August 27th, 2019
Summary: Do you want to major in Astrophysics? Are you thinking about becoming (or ever just wondered how one becomes) an Astrophysicists? Do you want to know Matt O’Dowd’s origin story? Then buckle up and enjoy the ride and try your astrophysics skill in calculating bubble universes to try to win some free Space Time Swag from the Merch Store.
Episode 29: Could We Terraform Mars?
Air Date: September 17th, 2019
Summary: Humanity’s future is glorious. As we master space travel, we’ll hop from one lifeless world to the next. Life will blossom in our path and the galaxy with shimmer with beautiful Earth-like orbs. Hmmm… maybe. This won’t sound so far fetched if we prove we can do it at least once. If we successfully terraform Mars.
Episode 30: Is Pluto a Planet?
Air Date: September 24th, 2019
Summary: You know what a planet is, right? A big round thing that orbits a star. Uh, not so fast. The surprisingly vicious debate over the planetary status of Pluto has given us a fascinating glimpse into what a scientific definition really is. And perhaps the word planet is too vague to be used as a scientific definition at all.
Episode 32: Black Hole Harmonics
Air Date: October 8th, 2019
Summary: Black holes are crazy enough on their own – but crash two together and you end up with a roiling blob of inescapable space that vibrates like a beaten drum. And the rich harmonics of those vibrations, seen through gravitational waves, could hold the secrets to the nature of the fabric of spacetime itself. Today on space time journal club we’ll explore the papers that claim to have detected black hole harmonics. We’ll also give you the latest updates on the most recent – in some cases quite bizarre - LIGO detections.
Episode 34: Is Time Travel Impossible?
Air Date: October 22nd, 2019
Summary: Time travel stories are cool because both the past and future are somehow more interesting that the present and because everyone wants a redo. But so far it appears we’re doomed to live consumed by regret in the eternal, boring present. Time marches on, inexorably and only forward. Or so we thought until Einstein came along. His special and general theories of relativity changed the way we think about time forever, and believe it or not, their raw equations permit time travel. They even tell us how to do it. So let’s review the possibilities, and decide how possible they really are.
Episode 35: Why We Might Be Alone in the Universe
Air Date: November 5th, 2019
Summary: Why does it appear, that humanity is the lone intelligence in the universe? The answer might be that planet Earth is more unique than we've previously assumed. The rare earth hypothesis posits exactly this - that a range of factors made Earth exceptionally unusual and uniquely able to produce intelligent life.
Episode 36: Does Life Need a Multiverse to Exist?
Air Date: November 12nd, 2019
Summary: Life exists in our universe. There we go - one hopefully uncontroversial statement. Therefore our universe is capable of producing and supporting life. How am I going? Two for two? Let’s try for three - therefore there are countless universes. Hmmm. Did I break my streak?
Episode 37: Can You Observe a Typical Universe?
Air Date: November 19th, 2019
Summary: The moment you started observing reality, you hopelessly polluted any conclusions you might make about it. The anthropic principle guarantees that you are NOT seeing the universe in most typical state. But used correctly, this highly controversial idea can be extremely powerful. So, how do you correctly use the anthropic principle?
Episode 39: The Doomsday Argument
Air Date: December 10th, 2019
Summary: Since the dawn of humanity around 100 billion people have lived. How many will live in the future of our species? We might hope for a trillion times that if we colonize the galaxy. But a simple statistical argument tells us that the doom of our species is much, much closer.
Episode 40: Do Black Holes Create New Universes?
Air Date: December 18th, 2019
Summary: What if every single black hole that formed in our universe sparked the big bang of a new universe? Cosmological natural selection proposes exactly this - but even better, it claims to be able to test the hypothesis.
Information about series and episodes are provided by TMDB API. If you think that episode information is wrong or missing, please click here to request an update. After your request, update process can take up to 30 minutes.