Is it right to waste helium on party balloons? https://www.bbc.co.uk/news/magazine-24903034
Category: GCSE Physics
Nov 16 2013
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Permanent link to this article: https://www.animatedscience.co.uk/2013/microwave-signals-turned-into-power
Nov 08 2013
Physics probes ‘splashback’ problem https://www.bbc.co.uk/news/science-environment-24820279
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Nov 07 2013
Scientists reveal the full power of the Chelyabinsk meteor explosion
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Oct 26 2013
Chris Hadfield: ‘I’m blind, in space, holding a drill. Houston, I have a problem’
Chris Hadfield: ‘I’m blind, in space, holding a drill. Houston, I have a problem’
An extract from Chris Hadfield’s An Astronaut’s Guide To Life On Earth
Fri 25 October 2013
I am calm the night before my first spacewalk in 2001, but I am also conscious I am about to do something I’ve been dreaming of most of my life. I feel ready – I’ve studied and trained for years. Still, I spend hours polishing the visor of my spacesuit so my breath won’t fog it up, unpacking and checking each piece of gear, pre-assembling as much of it as I can, then carefully attaching it to the wall with Velcro. My crewmate Scott Parazynski and I are installing Canadarm2, the robotic arm that will build the International Space Station, currently still in its infancy. We docked our space shuttle, Endeavour, to it a few days before, but haven’t yet been able to open the hatch because our EVA (extravehicular activity, or spacewalk) is going to take place from the shuttle airlock – essentially a depressurised bridge between the two spacecraft.
There are multiple steps to follow for an EVA; mess one up and you won’t make it out of the spaceship. It will be many busy hours until we can float out of the airlock and Nasa has choreographed them down to five-minute slices, even dictating when and what to eat for breakfast: PowerBars and rehydrated grapefruit juice. I shave, wash up (hair-washing involves scrubbing your scalp vigorously with no-rinse shampoo, then drying off carefully to be sure stray wet hairs don’t wind up floating all over the spacecraft and clogging up air filters or eyes and noses) and use the toilet. (You pick up a thing that looks like a DustBuster with a little yellow funnel attached, then hold it up close so you don’t get pee everywhere. I don’t want to have to use my diaper if I can help it.) Then I pull on the liquid cooling garment, which is like long underwear with a lot of personality; it’s full of clear plastic tubing that water flows through, and we can control the temperature. It feels stiff, like a cheap Halloween costume, but when the sun is shining on you in a spacewalk, the fabric of the spacesuit gets extremely hot and personal air-conditioning seems like a fine idea.
Four hours later, Scott and I are finally floating head to toe in our spacesuits, carefully and slowly depressurising the airlock and checking and rechecking the LED displays on our suits to make sure that they are functioning properly and can keep us alive in the vacuum of space. If there is a leak in the suit out there, our lungs will rupture, our eardrums burst, our saliva, sweat and tears boil, and we’ll get the bends. The only good news is that within 10 to 15 seconds we’ll lose consciousness. Lack of oxygen to the brain is what will finish us off.
When the airlock has finally depressurised, I grab the handle on the hatch and turn it – not easily, because nothing in a spacesuit is easy. The hatch is like a manhole, and it has to be removed and stowed in a bike rack-like contraption overhead. My exit will not be graceful. But my number one concern is to avoid floating off into space, so I’m tethered to Scott and I’m holding another tether to attach to the rail on the side of the shuttle. I lower the gold shield on my visor to protect my eyes from the sun and carefully, gingerly, wriggle my bulky suited self out of the airlock. I’m still inside the belly of the beast, in the payload bay, but my suit has become my own personal spaceship, keeping me alive.
Emerging from the bay, my existence narrows to a single point of focus: attaching my tether to the braided wire strung from one end of the vehicle to the other. I lock on to that and tell everyone I’m securely tethered. Now Scott can come and join me. Waiting for him, I check behind me, to be sure I haven’t accidentally activated my backup tank of oxygen, and that’s when I notice the universe. The scale is graphically shocking. The colours, too. The incongruity is stupefying: there I was, inside a small box, but now – how is this possible? What’s coming out of my mouth is a single word: “Wow.” Only elongated: “Wwwooooowww.” My mind is racing, trying to understand an experience that is so unique. It’s like being engrossed in cleaning a pane of glass, then you look over your shoulder and realise you’re hanging off the Empire State Building, Manhattan sprawled vividly beneath. Of course I’d peered through the shuttle windows at the world, but I understood now that I hadn’t seen it, not really. Holding on to the side of a spaceship that’s moving around the Earth at 17,500 miles an hour, I could truly see the astonishing beauty of our planet, the infinite textures and colours. On the other side of me, the black velvet bucket of space, brimming with stars. It’s vast and overwhelming, this visual immersion, and I could drink it in for ever, only here’s Scott, out of the airlock, floating over towards me. We get to work.
After five hours, the installation is going well, albeit slowly, when I become aware of droplets of water floating around inside my helmet. An EVA is incredibly taxing, physically, and over the years we’ve tried putting some sort of food inside the suit so we have something to eat. But it’s been messy and more hindrance than help, so typically we just have a water bag. You bite on the straw to open a valve, then suck out water – hypothetically, anyway. My water bag hasn’t worked since we started the EVA and now it is apparently leaking.
I’m trying to ignore these little globs of water floating in front of my face when suddenly my left eye starts stinging. It feels as if a large piece of grit has been smashed into it. Instinctively I reach up to rub it – and my hand smacks into my visor. “You’re in a spacesuit, moron!” I remind myself. I blink repeatedly and whip my head from side to side to try to dislodge whatever it is, but my eye won’t stay open for more than a blurry second.
We’ve trained for many eventualities during an EVA, but partial blindness is not one of them. I’m tightening the bolts on Canadarm2 using a big handheld drill. My feet are clicked into the foot restraints and my tether is firmly attached to the space station; I’m at no imminent risk. I decide to keep working and tell no one. I move on to the next bolt, but my left eye is now not only smarting but actually filling with tears.
Hadfield at work in orbit. Photograph: Nasa/Newsmakers/Getty Images
Tears need gravity. On Earth, a little duct above your eye generates tears that flush out any irritant, then overflow down your cheek. In weightlessness tears don’t flow downward. They just sit there and, as you keep on crying, a bigger and bigger ball of salty liquid accumulates to form a wobbly bubble on your eyeball. The growing ball of tears in my left eye oozes over, like a burst dam, invading my right. Within just a few minutes, I’ve gone from 20/20 vision to blind. In space. Holding a drill.
“Houston, EV1. I have a problem.” As the words come out, I can picture the reaction on the ground. First there will be concern for me personally and then, seconds later, everyone at Mission Control will be galvanised, tossing out theories about causes and trying to figure out solutions.
To Scott and me, under-reacting seems the best option: I can’t see, but he’s fine and still working on the wiring on another part of the station. I need to get this job done; the Canadian-designed and built Canadarm2 is both a test and proof of our robotics capability. Crew safety is the number one priority, but we can’t just leave this vital piece of equipment flapping off the side of the space station. The EVA is also a big deal back home: no Canadian has ever walked in space before. In other words, it’s not a good time to be having eye trouble.
The focus on the ground is figuring out what’s causing the contamination. They go straight to the worst-case scenario: maybe the problem is related to the air purification system in the spacewalking suit, which relies on lithium hydroxide to remove carbon dioxide. Lithium hydroxide is caustic and can severely damage your lungs; eye irritation is one of the first signs of a leak. So maybe I’m experiencing early symptoms of exposure and have only a couple more minutes to live. Ellen Ochoa, the Nasa “capcom” who’s the voice of Mission Control, calmly tells me to open my purge valve – essentially, open a hole in my suit.
This goes against my survival instincts, but I start dumping my air into space. I listen to the hissing noise as my oxygen merrily burbles out into the universe. It’s a curiously peaceful moment. Without sight, my body is telling me that nothing out of the ordinary is going on. I feel more like I’m under the covers in bed than hanging on to the side of the station, in mortal danger.
The suit has a significant amount of oxygen, enough for eight or even 10 hours, and I also have a secondary O2 tank, so I can bleed oxygen and stay alive for a long time. But who knows how much longer we’ll have to be outside to finish attaching the arm? I start trying everything I can think of to unblind myself: shaking my head around to brush my eyes against something in the helmet, blinking for all I’m worth. I know the doctors on the ground are undoubtedly saying, “We’ve got to bring him inside right this minute and figure out what’s going on.” So I say, “I feel no lung irritation at all and I think my eyes are starting to clear a little bit.” It’s sort of true. I feel marginally less sightless. I keep blinking and thankfully, 20 minutes on, I think I can see well enough to continue.
Nearing the end (almost three hours later), I look down to watch the world pour by. Having overcome this obstacle and knowing the two of us have accomplished what we set out to do is a big moment. But with a spacewalk, the very last step is as important as the first one, so not until we’ve repressurised the airlock and are actually back inside our spaceship do I let myself relax. As soon as I do, I feel completely drained and just float limply, shivering with cold. My body is out of fuel.
Later, as we’re going over the possibilities of what went wrong, the capcom asks, “Chris, did you remember to use your anti-fog stuff?” Of course I had. The night before I’d polished the visor of the suit. “You didn’t get it all off.” Apparently the solution is basically dishwashing detergent; mix it with a few droplets of loose water and it’s as though you’ve squirted soap directly into your eye. A spacewalk with a multimillion-dollar piece of equipment absolutely vital to the construction of the ISS was jeopardised because of a microscopic drop of cleaning solution.
Eventually, Nasa changed the solution to something less noxious. But in the meantime, thanks to my widely publicised oversight, all astronauts knew to be fanatical about wiping down the interior of their visors. Even in my line of work, it’s the small stuff.
I missed my children in space, but no more than I do on the ground, where I don’t see enough of them either. And I missed my wife. But I wasn’t lonely. Loneliness, I think, has very little to do with location. It’s a state of mind. In the centre of every city are some of the loneliest people in the world. If anything, because our whole planet was just outside the window, I felt even more aware of and connected to the seven billion other people who call it home.
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Oct 16 2013
Meteorite pulled from Russian lake https://www.bbc.co.uk/news/science-environment-24550941
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Oct 08 2013
Fusion milestone passed at US lab https://www.bbc.co.uk/news/science-environment-24429621
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Oct 08 2013
Blu-Ray albums target hi-fi fans https://www.bbc.co.uk/news/entertainment-arts-24441979
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