Space and astronomy news
I’m not saying it’s aliens, but it’s aliens. Actually, it’s almost certainly not aliens, or a wormhole, or a multiverse. When scientists discover something unusual, they make guesses about what’s happening. But Occam’s Razor encourages us to consider the probabilities of different events before making any concrete predictions.
Continue reading “Astronomy Cast Ep. 390: Occam’s Razor and the Problem with Probabilities”
Host: Fraser Cain (@fcain)
Special Guest: Dr. Matthew Golombek, JPL Project Scientist for MER, and working on the NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Discovery Program mission.
Guests:
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Kimberly Cartier (@AstroKimCartier )
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)
Paul Sutter (pmsutter.com / @PaulMattSutter)
Ramin Skibba (raminskibba.net / @raminskibba)
Continue reading “Weekly Space Hangout – Oct. 23, 2015: Dr. Matthew Golombek”
One of the interesting consequences of quantum theory is that particles can randomly appear in the cosmos, and if you wait long enough, conscious minds and maybe even whole new Universes. Welcome to the baffling concept of Boltzmann brains.
We blow minds here on Guide to Space.
All we want is for you to start watching, especially on a topic that you knew something about. And then you say “whoa…” when you realize the cosmic scope of an idea, like black holes, gamma ray bursts, or the Fermi Paradox.
Today, I think some kind of warning is in order. We’re going to blow your mind so thoroughly, that you’re going to be a hollowed out shell for the next few days. You’ll going to stumble around, glassy-eyed, in an almost catatonic state as you contemplate the humbling awesomeness of the Universe.
Let’s start with a familiar landscape, the implications of infinite time and space. The Universe might be infinite in space. Once you’re talking about infinity, a lot of strange ideas join the party over at Prismo’s.
Even if the Universe isn’t infinite in space it’ll most likely be infinite in time, expanding at an accelerating pace thanks to the leftover momentum from the Big Bang and dark energy. One way or another, there’s infinity in play. Thanks to quantum mechanics, the Universe is all about probabilities.
The air inside your living room is most likely going to remain evenly spaced, so you can breathe it and stay conscious. But there’s a teeny, tiny chance. A chance so small, that it’s not worth considering, that all the atoms of air in the room will spontaneously shift their position into one tiny corner, or maybe to the Andromeda Galaxy. The chances are small, it’ll practically never happen.
Once you’re dealing with forever, however, almost never, means sometimes always. You can imagine a situation, in an incomprehensible amount of time where quantum fluctuations spontaneously generate a hydrogen atom, floating in space, or perhaps a sperm whale or potted petunias.
We’re talking a seriously long amount of time. Long after all the stars have used up their hydrogen and died. Long after even the most supermassive black holes have evaporated away. If you could wait long enough, these quantum fluctuations would just pop things into existence.
One of the most compelling ideas is the concept of a Boltzmann Brain, named after the physicist Ludwig Boltzmann. It’s possible that entire, fully conscious minds could appear randomly in the cosmos. Keep rolling the dice for an infinite amount of time, and eventually, you’re going to get that Paladin with 18 charisma, 18 strength and a dreamy voice like Patrick Stewart.
The chances of this are 10 to the power of 10 to the power of 50. That’s a huge huge number. Trust me, you’re going to need more pencils to even write it out. Actually, you could turn every atom of the Universe into a pencil and it wouldn’t be enough.
Just imagine what it would be like to be that self-aware conscious entity that suddenly appeared floating in a completely empty cosmos, contemplating the mystery and wonder of all that vast nothingness. Perhaps it’s just a bunch of telepathic screaming because one thing this particular brain was missing was the ability to survive in a vacuum.
Now, then imagine an entire planet, orbiting a sun-like star, filled with human beings and other life. Again, that number is even more incomprehensibly small, but it’s not zero. And so, in a Universe of infinite space, those things are popping up an infinite number of times, and in infinite time, it’ll happen an infinite number of times.
And now, I shall deliver the final mind bending blow. Imagine you took all the particles and energy in the entire Universe. All the protons, photons, neutrons and hadrons. There’s a tiny, tiny chance that all those particles could suddenly appear in an infinitely dense region of space, and undergo a rapid expansion.
In other words, it’s possible that another Big Bang could spontaneously appear in an infinite amount of time. How long? Physicist Sean Carroll has done the math. You’d just need to wait 10 to the power of 10 to the power of 10 to the power of 56 years for it to happen.
It’s a long time, but it’s not forever. So, in an infinite amount of time, you’ll get an infinite number of Big Bangs, spontaneously appearing in a finite Universe. Or an infinite number of Big Bangs happening all the time in an infinite Universe.
I’d drop my mic now, but it’s sort of clipped onto my shirt here. So imagine that’s what I just did.
Can’t wrap your mind around these ideas? Don’t worry, just wait a nearly infinite amount of time, and a better version of me will spontaneously appear to explain them a little better. Thanks infinity.
We love to bend minds here at the Guide to Space. What ideas should we talk about next? Post your suggestions in the comments!
This week astronomers announced an unusual transit signal from another star. Although it’s most likely a natural phenomenon, one remote possibility is that this is some kind of alien megastructure. Freeman Dyson and others have considered this idea for decades. Today we’ll talk about the kinds of structures that aliens might want to build.
Doesn’t it feel like the Universe is perfectly tuned for life? Actually, it’s a horrible hostile place, delivering the bare minimum for human survival.
Consider that incomprehensible series of events that brought you to this moment. In a way that we still don’t understand, a complex mix of chemicals came together in just the right combination to kick off the evolution of life.
Generation after generation of bacteria, insects, fish, lizards, mammals and eventually humans somehow successfully found a buddy and passed along their genetic material to another generation. Clever humans invented computers, the internet, YouTube, and somehow you found your way to this exact video, to hear these words. Whoa.
It’s amazing to consider the Universe we live in, and how it’s perfectly tuned for life. If just a single variable was a little bit different, life as we know it probably wouldn’t exist. Gravity might be a repulsive force. Pokemons might catch you.
Doesn’t it feel like the Universe was created especially for us? I mean, didn’t I already tell you that we’re all the center of the Universe?
I’m sad to say, but this couldn’t be further from the truth. The reality is that the Universe is 100% completely inhospitable. Well, apart from a thin layer on the surface of our Earth, but that’s got to be a rounding error. A fraction of a fraction of a fraction of the teeniest percent of the volume of the Universe. The rest of the Universe is bunk.
If I was plucked out of our cozy environment and dropped into the near vacuum of pretty much anywhere else, the only resource would be a handful of hydrogen atoms. And what can you do with a few hydrogen atoms? Nothing. It might even give Bear Grylls a run for his money. He might have a little more trouble on a star’s surface, crisping up in a heartbeat.
Into a black hole? Surface of a neutron star? Near an exploding supernova? Please enjoy the crushing pressures and hellish temperatures of Venus, or the freezing irradiated surface of Mars.
Earth itself is mostly a deathtrap. Travel down a few kilometers and you’d bake and crush from the rising temperatures of the Earth’s interior. Travel up and the air gets thin, cold and killy. In fact, without our technology heating, cooling, or helping us breathe, we wouldn’t last more than a few days on most of the planet.
When you think about the landscape of time, we even live in a brief thumbnail of a moment when Earth is hospitable. Over the next few billion years, the Sun is going to heat up to the point that the surface of Earth will resemble the surface of Venus. And then the last hospitable hidey-hole in the entire Universe, that we know of, will wink out. The Universe is as inhospitable as it could possibly be. That is, without being completely inhospitable.
Especially when you consider the timeframes, and the long future when all the stars have died, where there’s nothing but black holes and frozen matter, and the Universe finally ditches that rounding error, and becomes 100% purely inhospitable.
Cosmologists use a term known as the anthropic principle to explain this very special moment we find ourselves in. There’s the greater anthropic principle that says the Universe wouldn’t be here without us to observe it, but that seems nutty and egotistical.
The lesser anthropic principle says that if the Universe turned out any differently, we wouldn’t be here to observe it.
Imagine you threw a dart out the window of an airplane and it landed in a tiny spot on the surface of the Earth. What were the chances that it would land there? Almost zero. What a lucky spot.
You can imagine all kinds of other even more inhospitable Universes, where the conditions were never good enough for life to evolve, and so intelligent civilizations could never even ask the question, “Is Our Universe Perfect for Life.”
So when you look out across a meadow in the springtime. The birds are chirping, and there’s new growth everywhere, don’t forget about the boiling rock magma beneath your feet, the frigid air and then vacuum above your head, and the whole Universe of burning, radiating, impacting objects trying their best to kill you.
Of all the extreme environments in the Universe, which ones do you find most fascinating? Tell us in the comments below.
Host: Fraser Cain (@fcain)
Special Guest: Dr. Carolyn Porco is the leader of the Cassini Imaging Science team and the Director of the Cassini Imaging Central Laboratory for Operations (CICLOPS) at the Space Science Institute in Boulder, Colorado.
Guests:
Pamela Gay (cosmoquest.org / @cosmoquestx / @starstryder)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Kimberly Cartier (@AstroKimCartier )
Dave Dickinson (@astroguyz / www.astroguyz.com)
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)
Alessondra Springmann (@sondy)
Rhys Taylor (G+: Rhys Taylor)
Continue reading “Weekly Space Hangout – Oct. 16, 2015: Dr. Carolyn Porco and Cassini Update; Sexual Harassment in Astronomy and Academia”
We know that the Sun will last another 5 billion years and then expand us a red giant. What will actually make this process happen?
One of the handy things about the Universe, apart from the fact that it exists, is that it lets us see crazy different configurations of everything, including planets, stars and galaxies.
We see stars like our Sun and dramatically unlike our Sun. Tiny, cool red dwarf stars with a fraction of the mass of our own, sipping away at their hydrogen juice boxes for billions and even trillions of years. Stars with way more mass than our own, blasting out enormous amounts of radiation, only lasting a few million years before they detonate as supernovae.
There are ones younger than the Sun; just now clearing out the gas and dust in their solar nebula with intense ultraviolet radiation. Stars much older than ours, bloated up into enormous sizes, nearing the end of their lives before they fade into their golden years as white dwarfs.
The Sun is a main sequence star, converting hydrogen into helium at its core, like it’s been doing for more than 4.5 billion years, and will continue to do so for another 5 or so. At the end of its life, it’s going to bloat up as a red giant, so large that it consumes Mercury and Venus, and maybe even Earth.
What’s the process going on inside the Sun that makes this happen? Let’s peel away the Sun and take a look at the core. After we’re done screaming about the burning burning hands, we’ll see that the Sun is this enormous sphere of hydrogen and helium, 1.4 million kilometers across, the actual business of fusion is happening down in the core, a region that’s a delicious bubblegum center a tiny 280,000 kilometers across.
The core is less than one percent of the entire volume, but because the density of hydrogen in the chewy center is 150 times more than liquid water, it accounts for a freakishly huge 35% of its mass.
It’s thanks to the mass of the entire star, 2 x 10^30 kg, bearing down on the core thanks to gravity. Down here in the core, temperatures are more than 15 million degrees Celsius. It’s the perfect spot for nuclear fusion picnic.
There are a few paths fusion can take, but the main one is where hydrogen atoms are mushed into helium. This process releases enough gamma radiation to make you a planet full of Hulks.
While the Sun has been performing hydrogen fusion, all this helium has been piling up at its core, like nuclear waste. Terrifyingly, it’s still fuel, but our little Sun just doesn’t have the temperature or pressure at its core to be able to use it.
Eventually, the fusion at the core of the Sun shuts down, choked off by all this helium and in a last gasp of high pitched mickey mouse voice terror the helium core begins to contract and heat up. At this point, an amazing thing happens. It’s now hot enough for a layer of hydrogen just around the core to heat up and begin fusion again. The Sun now gets a second chance at life.
As this outer layer contains a bigger volume than the original core of the Sun, it heats up significantly, releasing far more energy. This increase in light pressure from the core pushes much harder against gravity, and expands the volume of the Sun.
Even this isn’t the end of the star’s life. Dammit, Harkness, just stay down. Helium continues to build up, and even this extra shell around the core isn’t hot and dense enough to support fusion. So the core dies again. The star begins to contract, the gravitational energy heats up again, allowing another shell of hydrogen to have the pressure and temperature for fusion, and then we’re back in business!
Our Sun will likely go through this process multiple times, each phase taking a few years to complete as it expands and contracts, heats and cools. Our Sun becomes a variable star.
Eventually, we run out of usable hydrogen, but fortunately, it’s able to switch over to using helium as fuel, generating carbon and oxygen as byproducts. This doesn’t last long, and when it’s gone, the Sun gets swollen to hundreds of times its size, releasing thousands of times more energy.
This is when the Sun becomes that familiar red giant, gobbling up the tasty planets, including, quite possibly the Earth.The remaining atmosphere puffs out from the Sun, and drifts off into space creating a beautiful planetary nebula that future alien astronomers will enjoy for thousands of years. What’s left is a carbon oxygen core, a white dwarf.
The Sun is completely out of tricks to make fusion happen any more, and it’ll now cool down to the background temperature of the Universe. Our Sun will die in a dramatic way, billions of years from now when it bloats up 500 times its original volume.
What do you think future alien astronomers will call the planetary nebula left behind by the Sun? Give it a name in the comments below.
So, how can galaxies be traveling faster than the speed of light when nothing can travel faster than light?
I’m a little world of contradictions. “Not even light itself can escape a black hole”, and then, “black holes and they are the brightest objects in the Universe”. I’ve also said “nothing can travel faster than the speed of light”. And then I’ll say something like, “ galaxies are moving away from us faster than the speed of light.” There’s more than a few items on this list, and it’s confusing at best. Thanks Universe!
So, how can galaxies be traveling faster than the speed of light when nothing can travel faster than light? Warp speed galaxies come up when I talk about the expansion of the Universe. Perhaps it’s dark energy acceleration, or the earliest inflationary period of the Universe when EVERYTHING expanded faster than the speed of light.
Imagine our expanding Universe. It’s not an explosion from a specific place, with galaxies hurtling out like cosmic jetsam. It’s an expansion of space. There’s no center, and the Universe isn’t expanding into anything.
I’d suggested that this is a terribly oversimplified model for our Universe expanding. Unfortunately, it’s also terribly convenient. I can steal it from my children whenever I want.
Imagine you’re this node here, and as the toy expands, you see all these other nodes moving away from you. And if you were to move to any other node, you’d see all the other nodes moving away from you.
Here’s the interesting part, these nodes over here, twice as far away as the closer ones, appear to move more quickly away from you. The further out the node is, the faster it appears to be moving away from you.
This is our freaky friend, the Hubble Constant, the idea that for every megaparsec of distance between us and a distant galaxy, the speed separating them increases by about 71 kilometers per second.
Galaxies separated by 2 parsecs will increase their speed by 142 kilometers every second. If you run the mathatron, once you get out to 4,200 megaparsecs away, two galaxies will see each other traveling away faster than the speed of light. How big Is that, is it larger than the Universe?
The first light ever, the cosmic microwave background radiation, is 46 billion light-years away from us in all directions. I did the math and 4,200 megaparsecs is a little over 13.7 billion light-years.There’s mountains of room for objects to be more than 4,200 megaparsecs away from each other. Thanks Universe?!?
Most of the Universe we can see is already racing away at faster than the speed of light. So how it’s possible to see the light from any galaxies moving faster than the speed of light. How can we even see the Cosmic Microwave Background Radiation? Thanks Universe.
Light emitted by the galaxies is moving towards us, while the galaxy itself is traveling away from us, so the photons emitted by all the stars can still reach us. These wavelengths of light get all stretched out, and duckslide further into the red end of the spectrum, off to infrared, microwave, and even radio waves. Given time, the photons will be stretched so far that we won’t be able to detect the galaxy at all.
In the distant future, all galaxies and radiation we see today will have faded away to be completely undetectable. Future astronomers will have no idea that there was ever a Big Bang, or that there are other galaxies outside the Milky Way. Thanks Universe.
I stand with Einstein when I say that nothing can move faster than light through space, but objects embedded in space can appear to expand faster than the speed of light depending on your perspective.
What aspects about cosmology still give you headaches? Give us some ideas for topics in the comments below.
Host: Fraser Cain (@fcain)
Guests:
Paul Sutter (pmsutter.com / @PaulMattSutter)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Kimberly Cartier (@AstroKimCartier )
Brian Koberlein (@briankoberlein / briankoberlein.com)
Continue reading “Weekly Space Hangout – Oct. 9, 2015: Nobel Prizes, Private Moon Launches & Water on Pluto!”
If you’re going to be in the Austin area on October 16/17, and you’re into space exploration, you’re going to want to check out the 2015 New World’s Conference.
Here’s a list of their speakers:
In addition to the speakers, they’re going to have a few fun activities, like a live performance by ArcAttack – Tesla Coil Musicians. I’ve seen them in person and they are awesome. 🙂
There are still tickets available, and if you sign up this week, you can get 50% off the entrance price. Click here, sign up and use the code NWAUSTIN50 before the end of October 10th, 2015.