Space and astronomy news
Host: Fraser Cain (@fcain)
Guests:
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Ramin Skibba (@raminskibba)
Brian Koberlein (@briankoberlein)
Continue reading “Weekly Space Hangout – Jan. 16, 2015: Hard Landings, False Alarms & Found Beagles”
Have you ever seen the beautiful auroral displays in the high latitudes? These are the Northern and Southern Lights. But what dark physics wizardry is going on to make this happen?
If you live in the high latitudes, like Alaska, or New Zealand, you’ve probably had a chance to see an aurora. Here in Canada, we call them the Northern Lights or the Aurora Borealis, but the lucky folks in the far southern latitudes see them too. On a good night, you can see flickering sheets of light that dance across the night sky, producing an amazing display of colors. You can see green, red and even yellow and purple ghostly displays.
So what causes the Northern Lights? They’re produced as our planet moves through the chemtrails emanating from the womp-rat sized exhaust ports of Planet X. Originating in the Bush-Cheney administration during a failed co-invasion attempt of the lizard people from the hollow part of the flat earth and aliens from John Carpenter’s THE THING. They cause diabetes, gluten sensitivity, itchy bun noodles and homeopathy and herald the coming of the Grand Nagus of MMA-UFC-ENTJ-LOL-WTF-BBQ. That is, if you believe everything you read on the internet.
Auroras are in fact caused by interactions between energetic particles from the Sun and the Earth’s magnetic field. The Earth is filled with liquid metal, and it rotates inside turning our planet into a giant magnet. Invisible magnetic field lines travel from the Earth’s northern magnetic pole to its southern magnetic pole. This is why compasses point north, they’re following the field lines produced by this giant metallic spinning goo core. Or as I like to call it “The Planetary Shield Generator”, which should not be confused with the giant whirling metallic debris field orbiting the Earth which is our “Alien Invasion Shield”. Which you can learn about in another episode.
So why would we need a Planetary Shield, you might ask? It is because we are perpetually under assault by our great enemy, the Sun. Our Sun is constantly releasing a flurry of energetic particles right at us. These particles are electrically charged and driven to Earth by the Solar Wind. When they encounter the Earth’s magnetic field, they’re forced into a spiral along the magnetic field lines. Eventually they collide with an oxygen or nitrogen atom in the Earth’s atmosphere and release photons of light.
So, thanks to the spinning magnet goo core, our planetary shield converts these particles into beautiful night time displays. Although there can be auroras almost any night in the highest latitudes, we see the most brilliant auroral displays after large flares on the Sun. The most powerful flares blast a hail of particles that’s so intense, auroral displays can be seen at mid and even low-latitudes. It sounds dangerous, but we’re perfectly safe here, beneath our protective atmosphere and magnetic field.
You might be amazed to know that auroral displays can even make sounds. People have reported crackling noises coming from the sky during an aurora. Even though the auroras themselves are at very high altitudes, the particle interactions can happen just a few hundred meters above the ground. People have reported hearing claps and crackles during an aurora, and this has been verified by microphones placed by scientists. If you could get high up into the atmosphere, I’m sure the sounds would be amazing.
The interactions between the Sun and our planet are just another gift we get from the night sky. If you’ve never seen an aurora with your own eyes, you really need to add them to your bucket list. Organize a trip to northern Europe or Alaska and get a chance to see this amazing display of nature.
Have you ever been lucky enough to see the Northern Lights? Tell us a story in the comments below.
Before NASA’s Kepler mission searched for exoplanets using the transit method, there was the European COROT mission, launched in 2006. It was sent to search for planets with short orbital periods and find solar oscillations in stars. It was an incredibly productive mission, and the focus of today’s show.
Continue reading “Astronomy Cast Ep. 364: The COROT Mission”
Gamma ray bursts are the most energetic explosions in the Universe, outshining the rest of their entire galaxy for a moment. So, it stands to reason you wouldn’t want to be close when one of these goes off.
If comics have taught me anything, it’s that gamma powered superheroes and villains are some of the most formidable around.
Coincidentally, Gamma Ray bursts, astronomers say, are the most powerful explosions in the Universe. In a split second, a star with many times the mass of our Sun collapses into a black hole, and its outer layers are ejected away from the core. Twin beams blast out of the star. They’re so bright we can see them for billions of light-years away. In a split second, a gamma ray burst can release more energy than the Sun will emit in its entire lifetime. It’s a super-supernova.
You’re thinking “Heck, if the gamma exposure worked for Banner, surely a super-supernova will make me even more powerful than the Hulk.” That’s not exactly how this plays out.
For any world caught within the death beam from a gamma ray burst, the effects are devastating. One side of the world is blasted with lethal levels of radiation. Our ozone layer would be depleted, or completely stripped away, and any life on that world would experience an extinction level event on the scale of the asteroid that wiped out the dinosaurs.
Astronomers believe that gamma ray bursts might explain some of the mass extinctions that happened on Earth. The most devastating was probably one that occurred 450 million years ago causing the Ordovician–Silurian extinction event. Creatures that lived near the surface of the ocean were hit much harder than deep sea animals, and this evidence matches what would happen from a powerful gamma ray burst event. Considering that, are we in danger from a gamma ray burst and why didn’t we get at least one Tyrannosaurus Hulk out of the deal?
There’s no question gamma ray bursts are terrifying. In fact, astronomers predict that the lethal destruction from a gamma ray burst would stretch for thousands of light years. So if a gamma ray burst went off within about 5000-8000 light years, we’d be in a world of trouble.
Astronomers figure that gamma ray bursts happen about once every few hundred thousand years in a galaxy the size of the Milky Way. And although they can be devastating, you actually need to be pretty close to be affected. It has been calculated that every 5 million years or so, a gamma ray burst goes off close enough to affect life on Earth. In other words, there have been around 1,000 events since the Earth formed 4.6 billion years ago. So the odds of a nearby gamma ray burst aren’t zero, but they’re low enough that you really don’t have to worry about them. Unless you’re planning on living about 5 million years in some kind of gamma powered superbody.
We might have evidence of a recent gamma ray burst that struck the Earth around the year 774. Tree rings from that year contain about 20 times the level of carbon-14 than normal. One theory is that a gamma ray burst from a star located within 13,000 light-years of Earth struck the planet 1,200 years ago, generating all that carbon-14.
Clearly humanity survived without incident, but it shows that even if you’re halfway across the galaxy, a gamma ray burst can reach out and affect you. So don’t worry. The chances of a gamma ray burst hitting Earth are minimal. In fact, astronomers have observed all the nearby gamma ray burst candidates, and none seem to be close enough or oriented to point their death beams at our planet. You’ll need to worry about your exercise and diet after all.
So what do you think? What existential crisis makes you most concerned, and how do gamma ray bursts compare?
The surface of Mars is a well worn place in the Solar System, heavily pounded by countless meteor impacts. And some of these craters are hundreds of millions of years old. So it’s unusual for there to be a completely fresh impact on the surface of Mars: but that’s just what NASA scientists discovered looking through a recent batch of images returned from NASA’s Mars Reconnaissance Orbiter.
You’re looking at an image taken by the Mars Context Camera, an instrument on board the Mars Reconnaissance Orbiter. In an older photograph taken of the region in February 2012, there was just a bunch of old craters. And then, in the newer image, taken June 2014, this fresh scar on the surface of Mars is clearly visible.
The crater itself is circular, but the blast of ejecta indicates that the object came in from the West, and struck the surface of Mars, blasting out a curtain of pulverized rock that covered the nearby surface. The impactor would have vaporized into a fireball of superheated rock, like a nuclear bomb exploding on the surface of Mars, while the eject blanket was shot out to the side.
This isn’t the first time spacecraft have detected new craters on Mars. In fact, the largest new crater discovered was half the length of a football field. And so far, researchers have turned up more than 400 new craters on the surface of Mars.
The Mars Context Camera has completely imaged the entire surface of Mars at least once during its 7-year mission. And with multiple passes, planetary scientists are starting to build up a picture of how the dynamic the surface of Mars can really be.
And of course, planetary scientists have discovered fresh craters on other locations in the Solar System. NASA’s Lunar Impact Monitoring Program turned up a bright meteoroid impact on March 17, 2013, and follow on observations by NASA’s Lunar Reconnaissance Orbiter turned up the impact location. The monitoring program has actually turned up more than 300 impacts so far. So if you’re walking around on the Moon, watch your head.
Source: NASA/JPL News Release
Host: Fraser Cain (@fcain)
Special Guest: Andy Weir , author of “The Martian”
Andy was first hired as a programmer for a national laboratory at age fifteen and has been working as a software engineer ever since. He is also a lifelong space nerd and a devoted hobbyist of subjects like relativistic physics, orbital mechanics, and the history of manned spaceflight. “The Martian” is his first novel.
Guests:
Morgan Rehnberg (cosmicchatter.org / @cosmic_chatter)
Ramin Skibba (@raminskibba)
Brian Koberlein (@briankoberlein)
Dave Dickinson (@astroguyz / www.astroguyz.com)
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)
Continue reading “Weekly Space Hangout – Jan 9, 2015: Andy Weir of “The Martian””
It’s been said that a single asteroid might be worth trillions of dollars in precious rare metals. Will we ever reach out and mine these space rocks? How hard could it be?
Here on Earth, precious metals like gold and silver are getting harder to find. Geologists are developing more elaborate ways to get at the veins of precious metals beneath the surface of the Earth. And for the truly rare metals, like platinum and iridium, forget about it. All the platinum ever mined in the history of the world would fit inside my basement, and it’s not that big of a basement.
There are asteroids out there, just floating past us, taunting us, containing mountains of precious minerals. There are iron-nickel asteroids made entirely of metal. Comets of water, dirt and organic materials, everything you’d need to make an orbital farm. Just a single 30-meter asteroid, like the recently discovered 2012 DA14, is worth $20 trillion dollars. Now, if you could just somehow get to it.
Mining here on Earth is hard enough, but actually harvesting material from asteroids in the Solar System sounds almost impossible. But almost impossible, is still possible. With enough ingenuity and a few breakthroughs in spaceflight and robotics, plus some convenient hand waving for the sake of storytelling and there could be a future of asteroid mining ahead of us.
If there are mineral rich asteroids that contain a large amount of precious elements, it just might be cost effective to deliver those elements back to Earth. $20 trillion dollars sure would help buy that space elevator you wanted for sci-fi Christmas. If we had Robotic harvesters extract the gold, platinum and iridium off the surface of the space rock and they could send return capsules to Earth.
It would make even more sense to keep this stuff in space. Future spacecraft will need rocket fuel, hydrogen and oxygen, conveniently contained in water. If you could mine water ice off a comet or asteroid, you could create fuel depots across the Solar System.
Miners could extract and concentrate other materials needed for spaceflight and return them to Earth orbit. There could eventually be an orbiting collection of everything you need to survive in space, all gathered together and conveniently located … in space.
You might be surprised to know that getting to a nearby asteroid would require less energy than traveling to the Moon. Asteroids actually make better refueling stations than the Moon, and could serve as a waypoint to the other planets.
There are a few companies working to mine asteroids right now. Planetary Resources and Deep Space Industries have both developed plans for robotic missions to find asteroid targets, analyze them up close, and even return samples to Earth for study.
Within a few decades, they should have identified some ideal candidate asteroids for mining, and we get on with the work of mining with Solar System to support our further exploration. Perhaps then we’ll become a true spacefaring civilization, or just get conquered by an uprising of our sentient robotic miner drones.
So, will this ever happen? Will we eventually mine asteroids to send material back to Earth and support the exploration of space? Who knows. Business and industry are drivers of innovation. If there’s profit to be made, somebody will figure out how to do it.
What do you think? Do you envision a future career as an asteroid miner? Can we all be like Bruce Willis? Tell us in the comments below.
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Where on Earth did our water come from. Well, obviously not from Earth, of course, but from space. But did it come from comets, or did the water form naturally right here in the Solar System, and the Earth just scooped it up?
Continue reading “Astronomy Cast Ep. 363: Where Did The Earth’s Water Come From?”
Have you ever wondered how much water it would take to put out the Sun? It turns out, the Sun isn’t on fire. So what would happen if you did try to hit the Sun with a tremendous amount of water?
How much water would it take to extinguish the Sun? I recently saw this great question on Reddit, and I couldn’t resist taking a crack at it: We know that the question doesn’t make a lot of sense.
A fire is a chemical reaction, where material releases heat as it oxidizes. If you take away oxygen from a fire, it goes out. But.. there’s no oxygen in space, it’s a vacuum. So, there’s not a whole lot of room for regular flavor water-extinguishable fire in space. You know this. How many times have we had to seal off the living quarters and open the bay doors to vent all the oxygen in the space because there was a fire in the cargo bay? We have to do that, like, all the time.
Our wonderful Sun is something quite different. It’s a nuclear fusion reaction, converting hydrogen atoms into helium under the immense temperatures and pressures at its core. It doesn’t need oxygen to keep producing energy. It’s already got its fuel baked in. All the Sun needs is our adoration, quiet, and yet ever present fear. Only if we constantly pray will it be happy and perhaps we’ll go another day where it doesn’t hurl a giant chunk of itself at our smug little faces because it’s tired of our shenanigans.
So, I’m still going to take a swing at this question… so let’s talk about what would happen if you did pour a tremendous amount of water on the Sun? Let’s say another Sun’s worth of H20. Conveniently, Hydrogen is what the Sun uses for fuel, so if you give the Sun more hydrogen, it should just get larger and hotter.
Oxygen is one of the byproducts of fusion. Right now, our Sun is turning hydrogen into helium using the proton-proton fusion reaction. But there’s another type of reaction that happens in there called the carbon-nitrogen-oxygen reaction. As of right now, only 0.8% of the Sun’s fusion reactions proceed along this path.
So if you fed the Sun more oxygen as part of the water, it would allow it to perform more of these fusion reactions too. For stars which are 1.3 times the mass of the Sun, this CNO reaction is the main way fusion is taking place. So, if we did dump a giant pile of water onto the Sun, we’d just be making Sun bigger and hotter.
Conveniently, larger hotter stars burn for a shorter amount of time before they die. The largest, most massive stars only last a few million years and then they explode as supernovae. So, if you’re out to destroy the Sun, and you’re playing a really, really long game, this might actually be a viable route.
I’m pretty sure that wasn’t the intent though. Let’s say we just want to snuff out the Sun. Vsauce provides a strategy for this. If you could somehow blast your water at the Sun at high enough velocity, you might be able to tear it apart. If you can reduce the Sun’s mass, you can decrease the temperature and pressure in its core so that it can no longer support fusion reactions.
I’m going to sum up. The Sun isn’t on fire. There’s no amount of water you could add that would quench it, you’d just make it explode, but if you used firehoses that could spray water at nearly the speed of light, you could probably shut the thing off and eventually freeze us all, which is what I think you were hoping for in the first place.
What do you think? What else could we do to snuff out the Sun?
Think big. Really big. Like, cosmic big. How big can things in the Universe get? Is a galaxy big? What about a supercluster? What is the biggest thing in the Universe?
Our observable Universe is a sphere 96 billion light-years across, and the entire Universe might be infinite in size. Which is a hoarders dream walk-in closet space stuffed full of “things”. It’s loaded down with so much stuff, we’ve even given up naming things individually and now just spew out a list of letters and numbers to try and keep track of it all.
So, as is traditional, in a fit of adolescent OCD and one-upmanship reserved generally for things like tanks, planes and guns, we’re drawn to the question… What’s the biggest thing in the Universe. Well, 14 year old Fraser Cain, put down your copy of “Weapons and Warfare Volume 3” which you picked up at the dollar store as part of an incomplete set, as this is going to get a little tricky.
It all depends on what you mean by a “thing”. The biggest physical object is probably a star. The largest possible red giant star could be as big as 2,100 times the size our Sun. Placed inside our own Solar System, a monster star like this would extend out past the orbit of Saturn. That’s big, but we might be able to get even bigger if we’re willing to get past the idea that a “thing” has to be a homogeneous physical object.
Consider the regions around supermassive black holes. Within our own galaxy, things are pretty quiet, but around actively feeding black holes, there can be disks of material with such temperature and density that they act like the core of a star, fusing hydrogen into helium. Which, purely based on high volumetric density of pure awesome, I’m going to call a thing. An accretion disk around a quasar could be light days across, extending well past the orbit of Pluto and killing us all, if you dumped it in our Solar System.
If we’re going to be all philosophical about what constitutes a “thing” and you’re not all fussy about physical structure and just want a collection of material held together by gravity, then we can really can make some leaps and bounds in our “who’s got the biggest” measuring contest. Our own galaxy extends up to 120,000 light-years across.
There are much larger galaxies, ones that make the Milky Way look like that cat leash pendant from Men In Black 2. And ours is just one contained within a much larger cluster of galaxies known, rather unimaginatively, as the Local Group. Don’t let the centrist name fool you, this cluster contains around 50 galaxies and measures more than 10 million light-years across.
And we’re just getting started. The Local Group is one part of the Virgo Supercluster. A massive galactic structure that measures 110 million light-years apart. In 2014, astronomers announced that the Virgo Supercluster is just one lobe of an even larger structure, beautifully known as Laniakea, or “Immeasurable heaven” in Hawaiian. The name originated from Nawa’a Napoleon, an associate professor of Hawaiian Language at Kapiolani Community College. It honors the Polynesian sailors using “heavenly knowledge” navigating the Pacific Ocean, reminding us that romance is still alive and well in space and astronomy. Laniakea is centered around the Great Attractor – a mysterious source of gravity drawing galaxies towards it.
I almost forgot about our size contest. So who’s got the biggest space thing? According to buzzkill Ethan Siegel from the Starts With a Bang blog, you can’t actually have a structure that’s as big as Laniakea, and call it a thing. The fine-print reality is that the expansion of the Universe is being accelerated by dark energy. These galaxies are being pushed apart by dark energy faster than gravity can pull them together. So they’d never be able to form into a single object given enough time.
In other words, the largest possible object is a collection of galaxies at the exact size where gravity is just strong enough to overcome the expansive force of dark energy. Beyond that, everything’s getting spread apart, and it’s for our purposes we’re actually going to draw a line and say it’s not quite right to call it a thing. Unless you’d suggest a giant expanse of nothing is a thing… but let’s save that for another episode.
So what do you think? Do you feel like it’s right to call superclusters like Laniakea “a structure”?