Posted on by Fraser Cain

How Do Astronauts Avoid Debris?

How Do Astronauts Avoid Debris?

So, just how do we keep our space stations, ships and astronauts from being riddled with holes from all of the space junk in orbit around Earth?

We revel in the terror grab bag of all the magical ways to get snuffed in space. Almost as much as we celebrate the giant brass backbones of the people who travel there.

We’ve already talked about all the scary ways that astronauts can die in space. My personal recurring “Hail Mary full of grace, please don’t let me die in space” nightmare is orbital debris.

We’re talking about a vast collection of spent rockets, dead satellites, flotsam, jetsam, lagan and derelict. It’s not a short list. NASA figures there are 21,000 bits of junk bigger than 10 cm, 500,000 particles between 1 and 10 cm, and more than 100 million smaller than 1 cm. Sound familiar, humans? This is our high tech, sci fi great Pacific garbage patch.

Sure, a tiny rivet or piece of scrap foil doesn’t sound very dangerous, but consider the fact that astronauts are orbiting the Earth at a velocity of about 28,000 km/h. And the Tang packets, uneaten dehydrated ice cream, and astronaut poops are also traveling at 28,000 km/h. Then think about what happens when they collide. Yikes… or yuck.

Here’s the International Space Station’s solar array. See that tiny hole? Embiggen and clarinosticate! That’s a tiny puncture hole made in the array by a piece of orbital crap.

The whole station is pummeled by tiny pieces of space program junk drawer contents. Back when the Space Shuttle was flying, NASA had to constantly replace their windows because of the damage they were experiencing from the orbital equivalent of Dennis the Menace hurling paint chips, fingernail clippings, and frozen scabs.

That’s just little pieces of paint. What can NASA do to keep Sandra Bullock safe from the larger, more dangerous chunks that could tear the station a new entry hatch?

For starters, NASA and the US Department of Defense are constantly tracking as much of the orbital debris that they can. They know the position of every piece of debris larger than a softball. Which I think, as far as careers go, would be grossly underestimated for its coolness and complexity at a cocktail party.

Artist's impression of debris in low Earth orbit. Credit: ESA
Artist’s impression of debris in low Earth orbit. Credit: ESA

“What do you do for a living?”
“Me, oh, I’m part of the program which tracks orbital debris to keep astronauts safe.”
“So…you track our space garbage?”
“Uh, actually, never mind, I’m an accountant.”

Furthermore, they’re tracking everything in low Earth orbit – where the astronauts fly – down to a size of 5 cm. That’s 21,000 discrete objects.

NASA then compares the movements of all these objects and compares it to the position of the Space Station. If there’s any risk of a collision, NASA takes preventative measures and moves the Space Station to avoid the debris.

The ISS has thrusters of its own, but it can also use the assistance of spacecraft which are docked to it at the time, such as a Russian Soyuz capsule.

NASA is ready to make these maneuvers at a moment’s notice if necessary, but often they’ll have a few days notice, and give the astronauts time to prepare. Plus, who doesn’t love a close call?

For example, in some alerts, the astronauts have gotten into their Soyuz escape craft, ready to abandon the Station if there’s a catastrophic impact. And if they have even less warning, the astronauts have to just hunker down in some of the Station’s more sturdy regions and wait out the debris flyby.

The Iridium constellation - a robust satellite network (Iridium)
The Iridium constellation – a robust satellite network (Iridium)

This isn’t speculation and overcautious nannying on NASA’s part. In 2009 an Iridium communications satellite was smashed by a dead Russian Kosmos-2251 military satellite. The collision destroyed both satellites instantly. As icing on this whirling, screaming metallic orbital-terror-cake, it added 2,000 new chunks of debris to the growing collection.

Most material was in a fairly low orbit, and much of it has already been slowed down by the Earth’s atmosphere and burned up.

This wasn’t the first time two star-crossed satellites with a love that could-not-be had a shrapnel fountain suicide pact, and I promise it won’t be the last. Each collision adds to the total amount of debris in orbit, and increases the risk of a run-away cascade of orbital collisions.

We should never underestimate the bravery and commitment of astronauts. They strap themselves to massive explosion tubes and weather the metal squalls of earth orbit in tiny steel life-rafts. So, would you be willing to risk all that debris for a chance to fly in orbit? Tell us in the comments below.

Posted on by Fraser Cain

What is the Habitable Zone?

What is the Habitable Zone?

We’ve found hundreds of exoplanets in the galaxy. But only a few of them have just the right combination of factors to hold life like Earth’s.


The weather in your hometown is downright uninhabitable. There’s scorching heatwaves, annual tyhpoonic deluges, and snow deep enough to bury a corn silo.

The bad news is planet Earth is the only habitable place we know of in the entire Universe. Also, are the Niburians suffering from Niburian made climate change? Only Niburian Al Gore can answer that question.

We as a species are interested in habitability for an assortment of reasons, political, financial, humanitarian and scientific. We want to understand how our own climate is changing. How we’ll live in the climate of the future and what we can do to stem the tide of what our carbon consumption causes.

There could be agendas to push for cleaner energy sources, or driving politicians towards climate change denial to maintain nefarious financial gain.

We also might need a new lilypad to jump to, assuming we can sort out the travel obstacles. The thing that interests me personally the most is, when can I see an alien?

The habitable zone, also known as the “Goldilocks Zone”, is the region around a star where the average temperature on a planet allows for liquid water with which to make porridge. It’s that liquid water that we hunt for not only for our future uses, but as an indicator of where alien life could be in the Universe.

Problems outside this range are pretty obvious. Too hot, it’s a perpetual steam bath, or it produces separate piles of hydrogen and oxygen. Then your oxygen combines with carbon to form carbon dioxide, and then hydrogen just buggers off into space.

This is what happened with Venus. If the planet’s too cold, then bodies of water are solid skating rinks. There could be pockets of liquid water deep beneath the icy surface, but overall, they’re bad places to live.

We’ve got this on Mars and the moons of Jupiter and Saturn. The habitable zone is a rough measurement. It’s a place where liquid water might exist.

"The Chemistry of the Solar System" by Compound Interest's Andy Brunning
“The Chemistry of the Solar System” by Compound Interest’s Andy Brunning

Unfortunately, it’s not just a simple equation of the distance to the star versus the amount of energy output. The atmosphere of the planet matters a lot. In fact, both Venus and Mars are considered to be within the Solar System’s habitable zone.

Venusian atmosphere is so thick with carbon dioxide that it traps energy from the Sun and creates an inhospitable oven of heat that would quickboil any life faster than you can say “pass the garlic butter”.

It’s the opposite on Mars. The thin atmosphere won’t trap any heat at all, so the planet is bun-chillingly cold. Upgrade the atmospheres of either planet and you could get worlds which would be perfectly reasonable to live on. Maybe if we could bash them together and we could spill the atmosphere of one onto the other? Tell Blackbolt to ring up Franklin Richards, I have an idea!

When we look at other worlds in the Milky Way and wonder if they have life, it’s not enough to just check to see if they’re in the habitable zone. We need to know what shape their atmosphere is in.

Astronomers have actually discovered planets located in the habitable zones around other stars, but from what we can tell, they’re probably not places you’d want to live. They’re all orbiting red dwarf stars.

Goldilocks Zone
Artists impression of Gliese 581g. Credit: Lynette Cook/NSF

It doesn’t sound too bad to live in a red tinted landscape, provided it came with an Angelo Badalamenti soundtrack, red dwarf stars are extremely violent in their youth. They blast out enormous solar flares and coronal mass ejections. These would scour the surface of any planets caught orbiting them close enough for liquid water to be present.

There is some hope. After a few hundred million years of high activity, these red dwarf stars settle down and sip away at their fuel reserves of hydrogen for potentially trillions of years. If life can hold on long enough to get through the early stages, it might have a long existence ahead of it.

When you’re thinking about a new home among the stars, or trying to seek out new life in the Universe, look for planets in the habitable zone.

As we’ve seen, it’s only a rough guideline. You probably want to check out the place first and make sure it’s truly liveable before you commit to a timeshare condo around Gliese 581.

Do you think habitable planets are common in the Milky Way? Tell us what your perfect planet environment might be in the comments below.

Posted on by Fraser Cain

Weekly Space Hangout – June 26, 2015: Paul Sutter, CCAPP Visiting Fellow

Host: Fraser Cain (@fcain)

Special Guest: This week we welcome Paul Sutter, the CCAPP Visiting Fellow who works on the cosmic microwave background and large-scale structure.

Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Brian Koberlein (@briankoberlein / briankoberlein.com)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Alessondra Springmann (@sondy)
Continue reading “Weekly Space Hangout – June 26, 2015: Paul Sutter, CCAPP Visiting Fellow”

Posted on by Fraser Cain

Will We Ever Reach Another Star?

Will We Ever Reach Another Star?

We hear about discoveries of exoplanets every day. So how long will it take us to find another planet like Earth?

There are two separate parts of your brain I would like to speak with today. First, I want to talk to the part that makes decisions on who to vote for, how much insurance you should put on your car and deals with how not paying taxes sends you to jail. We’ll call this part of your brain “Kevin”.

The rest of your brain can kick back, especially the parts that knows what kind of gas station you prefer, whether Lena Dunham is awesome or “the most awesome”, whether a certain sports team is the winningest, or believes that you can leave a casino with more money than you went in with. We will call this part “Other Kevin”, in honor of Dave Willis.

Okay Kevin, you’re up. I’m going to cut to the gut punch, Kevin. Between you and me, it is my displeasure to inform you that science fiction has ruined “Other Kevin”. Just like comic books have compromised their ability to judge the likelihood of someone acquiring heat vision, science fiction has messed up their sense of scale about interstellar travel.

But you already knew that. Not like “Other Kevin”, you’re the smart one. In the immortal words of Douglas Adams, “space is big”. But when he said that, Douglas was really understating how mind-bogglingly big space really is.

The nearest star is 4 light years away. That means that light, traveling at 300,000 kilometers per second would still need 4 YEARS to reach the nearest star. The fastest spacecraft ever launched by humans would need tens of thousands of years to make that trip.

But science fiction encourages us to think it’s possible. Kirk and Spock zip from world to world with a warp drive violating the Prime Directive right in it’s smug little Roddenberrian face. Han and Chewy can make the Kessel run in only 12 parsecs, which is confusing and requires fan theories to resolve the cognitive space-distance dissonance, and Galactica, The SDF 3, and Guild Navigators all participate in the folding of space.

And science fiction knows everything that’s about to happen, right? Like cellphones. Additionally Kevin, I know what you’re thinking and I’m not going to tear into Lucas on this. It’s too easy, and my ilk do it a little too often. Plus, I’m saving it up for Abrams. Sorry Kevin. Got a little distracted there.

The point is, science fiction is doing colossal hand waving. They’re glossing over key obstacles, like the laws of physics.

Stay with me here.This isn’t like jaywalking bylaws that “probably don’t apply to you at that very moment”, these are the physical laws of the universe that will deliver a complete junk-kicking if you try and pretend they’re not interested in crushing your little atmosphere requiring, century lifespan, conventional propulsion drive dreams.

So let’s say that we wanted to actually send a spacecraft to another star, whilst obeying the laws of physics. We’ll set the bar super low. We’re not talking about massive cruise ships filled with tourists seeking the delights of the super funzone planetoid, Itchy and Scrachylandia Prime.

David Hardy's illustration of the Daedalus Project envisioned by the British Interplanetary Society: a spacecraft to travel to the nearest stars. (Credit: D. Hardy)
David Hardy’s illustration of the Daedalus Project envisioned by the British Interplanetary Society: a spacecraft to travel to the nearest stars. (Credit: D. Hardy)

I’m not talking about sending a crack team of power armored space marines to defend colonists from xenomorphs, or perhaps take other more thorough measures.

No, I’m talking about getting an operational teeny robotic spacecraft from Earth to Alpha Centauri. The fastest spacecraft we’ve ever launched is New Horizons. It’s currently traveling at 14 kilometres per second. It would take this peppy little probevette 100,000 years to get to the nearest star.

This is mostly due to our lack of reality shattering propulsion. Our best propellant option is an ion engine, used by NASA’s Dawn spacecraft. According to much adored Ian “Handsome” O’Neill from Discovery Space, we’d be looking at 19,000 years to get to Alpha Centauri if we used an ion engine and added a gravitational assist from the Sun.

Just think of what we could do with those 81,000 years we’d be saving! I’m going to learn the dulcimer!
We can start shearing back the reality curtain and throw money and resources to chase nearby speculative propulsion tech. Things like antimatter engines, or even dropping nuclear bombs out the back of a spacecraft

The best idea in the hopper is to use solar sails, like the Planetary Society’s Lightsail.
Use the light from the Sun as well as powerful lasers to accelerate the craft.

Ion Propulsion
Ion Propulsion System Test for Deep Space 1. Image Credit: NASA/JPL

But if we’re going to start down that road, we could also send microscopic lightsail spacecraft which are much easier to accelerate. Once these miniprobes reached their target, they could link up and form a communications relay, or even robotic factories.

Sorry, I think that was my “Other Kevin” talking. So where are we at, fo’ reals?

Harold “Sonny” White, a researcher with NASA announced that they’ve been testing out a futuristic technology called an EM drive. They detected a very slight “thrust” in their equipment that might mean it could be possible to maybe push a spacecraft in space without having to expel propellent like a chemical rocket or an ion drive.

What’s that, Kevin? Yes, you should totally be skeptical. You’re right, that last bit was a salad of weasel words.

Even if this crazy drive actually works, it still needs to obey the laws of physics. You couldn’t go faster than the speed of light and you would need a remarkable source of energy to power the reactor. Also, yes, Kevin, you’re right NASA is working on a warp drive. There’s no need to yell.

NASA is also working on an actual warp drive concept known as an alcubierre drive. It would actually do what science fiction has claimed: to warp space to allow faster than light travel. But by working on it, I mean, they’ve done a lot of fancy math.

But once they get all the math done, they can just go build it right? This concept is so theoretical that physicists are still arguing whether powering an alcubierre drive would take more energy than contained within the entire Universe. Which, I think we can call an obstacle.

Oh, one more thing. “Other Kevin”, thanks for being so patient. Here’s your reward. Unicorns are real, and Kevin has been lying to you this whole time. Go get ‘em tiger. Place your bets. When do you think we’ll send our first probe towards another star? Predict the departure date in the comments below.

Posted on by Fraser Cain

What Are The Biggest Mysteries in Astronomy?

What Are The Biggest Mysteries in Astronomy?

Black Holes? Dark Energy? Dark Matter? Alien Life? What are the biggest mysteries that still exist out there for us to figure out?

“The more I learn, the more I realize how much I don’t know.” These are the words of Albert Einstein. I assume he was talking about Minecraft, but I guess it applies to the Universe too.

There are many examples: astronomers try to discover the rate of the expansion of the Universe, and learn a dark energy is accelerating its expansion. NASA’s Cassini spacecraft finally images Saturn’s moon Iapetus, and finds a strange equatorial ridge – how the heck did that get there? Did the Celestials forget to trim it when it came out of the packaging?

There have always been, and, let’s go as far as to say that there always will be, mysteries in astronomy. Although the nature of the mysteries may change, the total number is always going up.

Hundreds of years ago, people wanted to know how the planets moved through sky (conservation of angular momentum), how old the Earth was (4.54 billion years), or what kept the Moon from flying off into space (gravity). Just a century ago, astronomers weren’t sure what galaxies were (islands of stars), or how the Sun generated energy (nuclear fusion). And just a few decades ago, we didn’t know what caused quasars (feeding supermassive black holes), or how old the Universe was (13.8 billion years). Each of these mysteries has been solved, or at least, we’ve a got a pretty good understanding of what’s going on.

Science continues to explore and seek answers to the mysteries we have, and as it does it opens up new brand doors. Fortunately for anyone who’s thinking of going into astronomy as a career, there are a handful of really compelling mysteries to explore right now:

Is the Universe finite or infinite? We can see light that left shortly after the Big Bang, 13.8 billion years in all directions. And the expansion of the Universe has carried these regions more than 45 billion light-years away from us. But the Universe is probably much larger than that, and may be even infinite.

Images from the Hubble Space Telescope showing a gravitational lensing effect. Credit: NASA/ESA.
Images from the Hubble Space Telescope showing a gravitational lensing effect. Credit: NASA/ESA.

What is dark matter? Thanks to gravitational lensing, astronomers can perceive vast halos of invisible material around all galaxies. But what is this stuff, and why doesn’t it interact with any other matter?

What is dark energy? When trying to discover the expansion rate of the Universe, astronomers discovered that the expansion is actually accelerating? Why is this happening? Is something causing this force, or do we just not understand gravity at the largest scales?

There are supermassive black holes at the heart of pretty much every galaxy. Did these supermassive black holes form first, and then the galaxies around them? Or was it the other way around?

The Big Bang occurred 13.8 billion years ago, and the expansion of the Universe has continued ever since. But what came before the Big Bang? In fact, what even caused the Big Bang? Has it been Big Bangs over and over again?

The Universe 590 million years after the Big Bang. Credit: Alvaro Orsi, Institute for Computational Cosmology, Durham University.
The Universe 590 million years after the Big Bang. Credit: Alvaro Orsi, Institute for Computational Cosmology, Durham University.

Are we alone in the Universe? Is there life on any other world or star system? And is anyone out there we could talk to?

Shortly after the Big Bang, incomprehensible amounts of matter and antimatter annihilated each other. But for some reason, there was a slightly higher ratio of matter – and so we have a matter dominated Universe. Why?

Is this the only Universe? Is there a multiverse of universes out there? How do I get to the Whedonverse?

In the distant future, after all the stars are dead and gone, maybe protons themselves will decay and there will be nothing left but energy. Physicists haven’t been able to catch a proton decaying yet. Will the ever?

And these are just some of the big ones. There are hundreds, thousands, millions of unanswered questions. The more we learn, the more we discover how little we actually understand.

Whenever we do a video about concepts in astronomy where we have a basic understanding, like gravity, evolution, or the Big Bang, trolls show up and say that scientists are so arrogant. That they think they know everything. But scientists don’t know everything, and they’re willing to admit when something is a mystery. When the answer to the question is: I don’t know.

What’s your favorite unanswered question in space and astronomy? Give us your best mystery in the comments below.

Posted on by Fraser Cain

NASA New Horizons Hangout – Countdown to Pluto, Friday 2:30 EDT

Can you believe it? We’re less than a month away from NASA’s New Horizons‘ historic flight past the dwarf planet Pluto. I’m sure you’ve got a zillion questions about the mission and want to hear how everything’s going.

Well, you’re in luck. Primary investigator Alan Stern, as well as several member of the science team and NASA will be on hand on Friday, June 19th at 11:30 am PDT (2:30 pm EDT) to have a special Google+ Hangout on Air just to talk about the mission. They’ll also be interacting with the audience and answering your questions about the mission.

Want to watch it live? Click here and then select that you’re going to attend. That’ll put the event right into your calendar. Then come back at 11:30/2:30 on Friday and watch it live.

New Horizons Hangout – Countdown to Pluto

Posted on by Fraser Cain

When Will We Find Another Earth?

When Will We Find Another Earth?

We hear about discoveries of exoplanets every day. So how long will it take us to find another planet like Earth?

Back in the olden days, astronomers could only guess if there were planets orbiting other stars.

These were the days when we had to wait at the bank to pay our bills, nobody carried computers in their pockets and those computers gave direct connections to everyone else’s pockets because pocket connectivity is highly important, school was uphill both ways, the number 6 was brand new, we recorded images on thin sheets of transparent plastic, 5 bees were worth a quarter and I had an onion tied to my belt, as was the style at the time.

With the discovery of a mega Jupiter-sized world orbiting the star 51 Pegasi in 1995, the floodgates opened up. In the years that followed, dozens more planets were discovered. Then hundreds, and now, we know about thousands orbiting other stars.

The bad news is we can’t get to any of them. The good news is most of these worlds suck. You don’t want any part of them. For starters their wifi is terrible.

Consider Kepler-70b. This world orbits its star 4 times in a 24 hour period. This means it’s super close, and a great place to really quickly win all the human torch cosplay competitions. The surface temperature is a completely unreasonable 7200 Kelvin, hotter than the surface temperature of the Sun.

There’s the planets orbiting pulsar PSR B1257+12, a millisecond pulsar in the constellation of Virgo. As they whip around their exotic host, they’re bathed in intense radiation. Which is generally considered bad for creatures who need functioning organs.

Perhaps HD 106906 b, orbiting its star 650 times more distantly than we orbit the Sun. You’d spend every second of your short life on that planet inventing new words for cold. And then you’d die. Cold.

Imagine a world that orbits a star like our Sun. A world made of about an Earth’s worth of rocky material that you could stand on, at just the right distance from its star that water can exist as a liquid.

This is what astronomers search for, the tri-wizard cup of extrasolar planetary research. Earth 2? Terra Nova? The Gaia part le deux.

Here’s the exciting part. Astronomers have found each of these characteristics in a planet, but never all together. They’ve found plenty of stars similar to our Sun, with planets orbiting them. In fact, the star HD 10180 is incredibly similar to the Sun, and astronomers have discovered 9 planets orbiting it so far. Which does have a familiar ring to it. No word so far on which ones are about to be demoted to dwarf planets.

Sizes and temperatures of Kepler discoveries compared to Earth and Jupiter
Sizes and temperatures of Kepler discoveries compared to Earth and Jupiter

They’ve found planets roughly the same mass as the Earth. Kepler-89, with 98% the mass of the Earth. So close! Sadly, it’s way too close to its parent hydrogen furnace to be habitable.

They’ve found planets in the habitable zone. Here on Earth, the global average temperature is -18 degrees C. Sounds cold, but the wintery nights in Antarctica absolutely wreck our GPA.

The closest analog discovered is Kepler-22b, with a global average temperature of -11C. So, it should feel downright balmy. Except, it’s about 2.4 times bigger than Earth and orbits a nasty red dwarf star.

Astronomers have even matched up two criteria at the same time. Earth-sized world orbiting around a Sun-like star, but it’s hellishly hot. Wrong flavor star but with the right temperature and size, it’s a veritable tic tac toe board of near wins.

So far, there hasn’t been a single extrasolar planet discovered that meets all three criteria. An Earth-sized world, orbiting a Sun-like star inside the habitable zone where liquid water could be present.

Astronomers were hoping that NASA’s Kepler spacecraft would have been the first to discover Earth 2.0. It had already turned up thousands of planets, including many of the ones I’ve already mentioned.

Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech
Artist’s conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech

Sadly, just a few years into the mission, it lost too many reaction wheels, which allow the spacecraft to change direction. It wasn’t able to make enough observations to help confirm a true Earth 2.0. Kepler is still searching for planets, but with a reduced ability to point, it’s only looking at red dwarf stars.

Don’t worry, NASA’s Transiting Exoplanet Survey Satellite will launch in 2017, and will survey a region of the sky 400 times larger than Kepler did. It should turn up thousands of planets, Earth-sized and larger.

Once we actually find New Terra, things get really interesting. Astronomers will search those planets for life. I know it sounds almost impossible to see life from this distance, but astronomers know that if they can analyze the atmosphere of these worlds, they can detect life flourishing there.

They might even be able to detect the pollution from their alien cars and heavy industry, contributing to their CO2 levels, and learn we’re not so different after all. Even if they’re icky bug people.

At the time I’m recording this video, no analog Earth planet has been discovered so far. But it’s just a matter of time. In the next few decades astronomers are going to find that first Earth 2.0, and then dozens, then hundreds, and even figure out which ones have life on them.

It’s a great time to be alive. Place your bets. Predict the date astronomers announce that we’ll find Earth 2.0. Put your guess into the comments below.

Posted on by Fraser Cain

Astronomy Cast Ep. 381: Hollowing Asteroids in Science and Fiction

When we finally make the jump to fully colonizing the Solar System, we’re going to want to use asteroids as stepping stones. We can use them as way stations, research facilities, even as spacecraft to further explore the Solar System. Today we’ll talk about the science and science fiction of hollowing out asteroids.
Continue reading “Astronomy Cast Ep. 381: Hollowing Asteroids in Science and Fiction”