Special Guest: Miguel Drake-McLaughlin returns for another visit! He’s the Director of the new documentary, Sky Line, The Space Elevator Documentary. The film debuted at DOC NYC 2015 [Nov 12-19] – America’s largest documentary festival — and will be released on all major On Demand platforms on November 20th, 2015.
We’ve featured the videos from Kurzgesagt many times before here on Universe Today and they’re always wonderful. Sometimes a terrific animation with adorable birds is worth a million words. In their latest video, they cover black holes, from birth to death, giving you an overview of these bizarre objects.
But this episode is very special for me because: I wrote it. Well, I contributed an initial script and Matt, a PhD astrophysicist from Quarks and Coffee, added his own flare and tightened up the science.
One of the biggest, most basic questions you can ask is: “why is there something and not nothing?” The reality is that we don’t know the answer, we might never know the answer. Let’s probe to the edge of what we can explain, and what ideas cosmologists have proposed to explain how we all got here.
Here is a sample of the extra content you can get if you join our Patreon campaign, and support the Guide to Space video series! We hope you laugh a bit at these bloopers from Guide to Space episodes 221-228, and like it enough to join us! Continue reading “Guide to Space Bloopers: Eps 221-228”
Every year, it’s the same dilemma: what gift should you get for the super space nerd in the family? And if someone has a budding interest in space and astronomy, what can you do to feed their hunger for knowledge? Today we’ll talk telescopes, books and planispheres. Everything you need to avoid a holiday gift disaster.
In science fiction, wormholes are a method often used to travel great distances across space. Are these magic bridges really possible?
With all my enthusiasm for humanity’s future in space, there’s one glaring problem. We’re soft meat bags of mostly water, and those other stars are really really far away. Even with the most optimistic spaceflight technologies we can imagine, we’re never going to reach another star in a human lifetime.
Reality tells us that even the most nearby stars are incomprehensibly far away, and would require vast amounts of energy or time to make the journey. Reality says that we’d need a ship that can somehow last for hundreds or thousands of years, while generation after generation of astronauts are born, live their lives and die in transit to another star.
Science fiction, on the other hand, woos us with its beguiling methods of advanced propulsion. Crank up the warp drive and watch the stars streak past us, making a journey to Alpha Centauri as quick as a pleasure cruise.
You know what’s even easier? A wormhole; a magical gateway that connects two points in space and time with one another. Just align the chevrons to dial in your destination, wait for the stargate to stabilize and then just walk… walk! to your destination half a galaxy away.
Yeah, that would be really nice. Someone should really get around to inventing these wormholes, ushering in a bold new future of intergalactic speedwalking. What are wormholes, exactly, and how soon until I get to use one?.
A wormhole, also known as an Einstein-Rosen bridge is a theoretical method of folding space and time so that you could connect two places in space together. You could then travel instantaneously from one place to another.
We’ll use that classic demonstration from the movie Interstellar, where you draw a line from two points, on a piece of paper and then fold the paper over and jab your pencil through to shorten the journey. That works great on paper, but is this actual physics?
As Einstein taught us, gravity isn’t a force that pulls matter like magnetism, it’s actually a warping of spacetime. The Moon thinks it’s just following a straight line through space, but it’s actually following the warped path created by the Earth’s gravity.
And so, according to Einstein and physicist Nathan Rosen, you could tangle up spacetime so tightly that two points share the same physical location. If you could then keep the whole thing stable, you could carefully separate the two regions of spacetime so they’re still the same location, but separated by whatever distance you like.
Climb down the gravitational well of one side of the wormhole, and then instantaneously appear at the other location. Millions or billions of light-years away. While wormholes are theoretically possible to create, they’re practically impossible from what we currently understand.
Albert Einstein, pictured in 1953. Photograph: Ruth Orkin/Hulton Archive/Getty Images Ruth Orkin/Getty
The first big problem is that wormholes aren’t traversable according to General Relativity. So keep this in mind; the physics that predicts these things, prohibits them from being used as a method of transportation. That’s a pretty serious strike against them.
Second, even if wormholes can be created, they’d be completely unstable, collapsing instantly after their formation. If you tried to walk into one end, you might as well be walking into a black hole.
Third, even if they are traversable, and can be kept stable, the moment any material tried to pass through – even photons of light – that would make them collapse.
There’s a glimmer of hope, though, because physicists still haven’t figured out how to unify gravity and quantum mechanics.
This means that the Universe itself might know things about wormholes that we don’t understand yet. It’s possible that they were created naturally as part of the Big Bang, when the spacetime of the entire Universe was tangled up in a singularity.
Astronomers have actually proposed searching for wormholes in space by looking for how their gravity distorts the light from stars behind them. None have turned up yet.
One possibility is that wormholes appear naturally like the virtual particles that we know exist. Except these would be incomprehensibly small, on the Planck scale. You’re going to need a smaller spacecraft.
Artist illustration of a spacecraft passing through a wormhole to a distant galaxy. Image credit: NASA.
One of the most fascinating implications of wormholes is that they could allow you to actually travel in time.
Here’s how it works. First, create a wormhole in the lab. Then take one end of the wormhole, put it on a spacecraft and fly away at a significant percentage of the speed of light, so that time dilation takes effect.
For the people on the spacecraft, just a few years will have occurred, while it could have been hundreds or even thousands for the folks back on Earth. Assuming you could keep the wormhole stable, open and traversable, then traveling through it would be interesting.
If you passed in one direction, you’d not only move the distance between the wormholes, but you’d also be transported to the time that the wormhole is experiencing. Go one direction and you move forward in time, go the other way: backwards in time.
Some physicists, like Leonard Susskind think this wouldn’t work because this would violate two of physics most fundamental principles: local energy conservation and the energy-time uncertainty principle.
Unfortunately, it really seems like wormholes will need to remain in the realm of science fiction for the foreseeable future, and maybe forever. Even if it’s possible to create wormholes, then you’ve got the keep them stable and open, and then you’ve got to figure out how to allow matter into them without collapsing. Still, if we could figure it out, that’d make space travel very convenient indeed.
If you could set up two ends of a wormhole to anywhere in the Universe, where would they be? Tell us your ideas in the comments below.
When humans finally blast off for another world, where will we be going? Will we return to the Moon, and take over where the Apollo astronauts left off, or will we press onto Mars, and set foot on a whole new planet?
Humanity is going to need to make a difficult choice in the next few years. One that will have implications for the very future of space exploration: classic Star Wars or the new Trilogy? Star Trek fans feel your pain.
But also, we’ll need to figure out whether we should push on with the human exploration of Mars, so that Mark Watney can fulfill his potato destiny, or return to the Moon and build Moonbase Alpha. It’s surprisingly difficult to choose.
First, the case for the Moon. Obviously, the Moon is close. It’s just a few hundred thousand kilometers away, and it only takes astronauts a few days to get there, land on the surface and continue our scientific exploration of this world – which we still know very little about.
Why is the far side so different from the near side? Are there lava tubes and even vast underground caverns that future colonists could live in? It would be great to get more geologist boots on the regolith to find out.
Although it’s expensive, going to the Moon could eventually pay for itself. There are vast reserves of Helium-3 just sitting on the surface of the Moon. This material is rare on Earth, and could be used for future fusion energy planets. Not to mention other valuable minerals and elements that might just be lying around, ready for collection and used for space-based manufacturing.
The Moon makes sense as a testing ground, for humanity to perfect the techniques of surviving and thriving off planet Earth. If we can make it there, then we stand a chance of going the distance as a true interplanetary species.
The big problem with the Moon is that it’s completely inhospitable to human life. There’s no atmosphere, no protection from the Sun’s radiation, enormous temperature variations and a gravity so low it could be lethal over the long term.
The lunar regolith is like tiny shards of glass that would get everywhere, into everything, and be a constant danger to anyone living on the Moon.You couldn’t imagine a worse place to live.
The Moon is close but it sucks, what about Mars? Mars is much much farther than the Moon; the average distance to Mars is about 225 million kilometers.
Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA
This means that a journey to Mars with even a short visit to the surface will take the better part of 2 years. Astronauts will be beyond any kind of rescue and completely reliant on their spacecraft and supplies for that entire journey.
During their voyage, they’ll be bombarded with radiation from the Sun and there’ll be no protection on the surface on the planet either, because Mars doesn’t have a global magnetosphere like Earth.
But once they do get to Mars, they’ll have a world that’s much more earthlike. The temperatures are extreme, but can be reasonable at the equator, in the middle of the day. There’s a slight atmosphere, and stronger gravity – maybe your bones won’t waste away if you spend too long there.
To say there’s science to be done on Mars is an understatement. There are so many different terrains, with different geologic features. There’s the outstanding question of whether there was ever life on Mars, and if it’s there now. We’d really like to know the answer.
The Martian regolith is smoother and safer than the lunar version, having been weathered down by wind over millennia. It would still get everywhere, but it wouldn’t give you lung disease.
We now know there are vast reserves of water under the surface of Mars, and astronauts will be able to use this for all kinds of projects, like growing plants, drinking water, breathable atmosphere and even rocket fuel.
Venus imaged by Magellan Image Credit: NASA/JPL
Sending humans to Mars is much more complicated and expensive than sending them to the Moon, and the level of space-based infrastructure would be much greater. Assuming we did this right, we’d have much more technology and a stronger presence in space.
Both Mars and the Moon have their pros and cons, but there’s another world that you might want to consider: Venus.
Although Venus is mostly a terrible hellscape, completely worthless down on the surface, where it’s hot enough to melt lead, and the atmospheric pressure is as bad as being a kilometer under the ocean. Did I mention it rains sulphuric acid?
But high up in the cloud tops of Venus, around 50 km altitude, the evil planet becomes downright habitable. You wouldn’t need to wear a spacesuit to regulate the delightful room temperature atmosphere. And you wouldn’t need a pressure suit, because it’s already perfect Earth pressure. You would, however, still need to worry about the sulphuric acid rain. And unless you’ve evolved to breathe carbon dioxide, you’ll need to keep a supply of oxygen handy.
NASA has already proposed sending dirigibles to Venus, filled with our breathable atmosphere for buoyancy, to explore. So maybe the next planet we set foot on, will be the one that we can never set foot on. Hmm, that sounded better in my brain.
You know what, I can’t choose. We should go back to the Moon, we should send humans to Mars, and we should explore Venus too. No matter where we go in the Solar System, it’s going to be an enormous undertaking. We’re going to need to develop new technologies, and risk the lives of everyone involved. But the rewards will be great, moving us one huge leap towards becoming a true interplanetary species.
So now it’s time for you to decide. The fate of humanity rests on your shoulders. Should we press on to Mars, or focus our energy on the Moon or even Venus? Give us your suggestions in the comments below.
In the last few episodes, we’ve been talking about the standard model of physics, explaining what everything is made up of. But the reality is that we probably don’t know a fraction of how everything is put together. This week we’re going to talk about baryons, the particles made up of quarks. The most famous ones are the proton and the neutron, but that’s just the tip of the baryonic iceberg. And then we’re going to talk about where the standard model ends, and what’s next in particle physics. Continue reading “Astronomy Cast Ep. 395: The Standard Model – Baryons and Beyond”
