Back in February I was visited by a film crew working for University College Oxford to showcase some of the work we do in Atmospheric Physics here in Oxford. You can see the finished product on vimeo.com. Hats off to Kerry Harrison of kerryharrisonphotography.com for some great footage!
Dr Leigh Fletcher from University College Oxford on Vimeo.
At Univ... from University College Oxford on Vimeo.
Wednesday, 18 April 2012
Friday, 13 April 2012
School Explorers
Recently I received a package of 30 or so letters from primary school students in Hinckley, Leicestershire (my old home town), and so I set about replying to them. The letter I sent in reply is recorded below, as I think it’s a great insight into how powerful space exploration can be in inspiring the next generation of explorers. I hope it’s helpful to others too!
“Thank you very much for all the letters you sent to me here in Oxford, it's so nice to know that people out there are interested in the work that we do, using our telescopes to look up at the night sky, trying to understand what it must be like on the other planets in our solar system. What would it be like to stand on the red dusty landscape of Mars under pink skies with blue sunsets? What would you hear if you stood in the middle of a gigantic lightning storm on Jupiter? Are there other worlds out there with life forms, walking around, sitting in schools, and asking questions about the night sky, just like you? I love my job as a space scientist, dealing with these sorts of questions every day. So I'll do my very best to answer all the questions you sent!
Questions about my job:
Lots of you wanted to know what NASA stands for - it's the National Aeronautics and Space Administration, an American government institution that manages the US space program. There's lots of NASA centres throughout the United States, and I work closely with two of them - Goddard Spaceflight Center near Washington DC, and the Jet Propulsion Laboratory in California. Lily, Anjan, William, Alisha and Joe wanted to know where I was based in America - we lived in California, and I worked for the Jet Propulsion Laboratory. Sakithya and Eden wanted to know how many people work at NASA - the answer is thousands, it’s a huge effort to send things into space. Here in Britain we have a much smaller agency called the UK Space Agency (UKSA), and with the rest of Europe we're all part of the European Space Agency (ESA).
Many of you asked what it's like to be a space scientist. I work in an office with lots of other scientists, using computers to understand what it's like on other planets. We build spacecraft to launch to other worlds and fly around them, sometimes to land on them to explore like a mini car on the surface. We also build big telescopes to fly in space and look out at the planets (you may have heard of Hubble), and we get to use big telescopes on Earth (some of them in Hawaii and Chile). It's a very exciting time, as telescopes and spacecraft get better and better, and we're learning more every day. One of the things we're looking for is a sign of life elsewhere in our solar system, but more on that later. Eden and Spencer wanted to know about the computers we use: I have about 3 different computers for different things, but we wouldn't be able to do our job without them - it's essential to be good at maths, and good at computing, to be a space scientist.
Joe, Daisy and William wanted to know how I got this job. When I left school in Hinckley at 18 years old, I went to university to study science, specifically physics. Once I was trained, I became a Doctor at the age of 26 (not of medicine, but a doctor of science), and started figuring out new ways of studying the planets. I spent a few years living in America, working for NASA, and that landed me the job I have today, as a researcher at Oxford University. K. Galloway wanted to know if the students at Oxford are well-behaved: I can tell you that they are most of the time, but every now and then they'll get into trouble! Keerthan wanted to know how long I've been a space scientist - the answer is about 8 years now.
About Astronauts:
Ruby, Holly, Lily and M. Brookes wanted to know if I ever get to go into space. Sadly not, because I'm not trained as an astronaut. I tried once, when the European Space Agency wanted astronauts to work on the International Space Station, but it's very hard to get a job like that. So I do the next best thing, sending big robotic spacecraft into space. Daisy wanted to know how you get to be an astronaut - you have to be physically fit, with good eyesight and excellent problem solving skills. They want you to be able to think quickly and make good decisions. Typically people are between the age of 18 and 28 when they apply, and it takes years to train before you get your first mission to fly into space.
Callum wanted to know if NASA sends astronauts into space - they certainly do, but now that the American space shuttle has stopped working, they have to fly on Russian rockets. Anjan and Francesca wanted to know how many space shuttles there were - there are three still in existence (Discovery, Endeavour and Atlantis), but two blew up during missions (Columbus and Challenger), showing you just how dangerous space travel is today. To answer Beth's and Francesca's question about how many people have flown in space, about 530 people have flown up there so far (an altitude of 62 miles up). Francesca wanted to know what's the longest time anyone has spent in space - 438 days, a record set by a Russian named Polyakov on the Mir space station in 1994. Lily and Aryana wanted to know when the first astronauts went into space - it all started in 1961 with Yuri Gagarin, a Russian who was the first man in space, over 50 years ago. Jude and Beth asked questions about the first man on the moon, Neil Armstrong: he was selected as a NASA astronaut when he was 32, flew on a Gemini mission when he was 36, and landed on the moon when he was 39. The total time he spent in space was 8.6 days.
Keerthan and Spencer asked how long it takes to get to space - the space shuttle used to take about 8 minutes from launch in Florida to get into orbit. Daisy, Ethan and Eden asked how long it takes to build the spaceship in the first place, and it's several years - the space probes I work on take at least 10 years to design, build and get to the launch pad, and they're about the size of an average car. Eden wanted to know how much fuel it takes - well the space shuttle used about 2 million litres to launch into space, that's the same as about 50'000 cars! Alisha wanted to know what you eat in space and why - well it's pretty much the same as on Earth, except they tend to dry it out so it doesn't weigh as much, then add water back to it later. One day you must really try some freeze-dried strawberries!
About space:
Now we get to some of the more scientific questions. Joe wanted to know when the universe began - well we don't know for certain, but we think that it was nearly 14 billion years ago, which is 14'000'000'000 years. The Earth has only been around for about 4.5 billion years, for comparison. M. Brookes wanted to know how big is space - well that’s a hard one, as we think the universe is infinitely large, so if you set off in one direction, you'll carry on going forever and ever and never reach the end of it!
Spencer asked how cold it is in space, and that's a good question - on Earth the air around us keeps us warm (it's an insulator), but as there's no air in space, there's no way to stay warm. The temperature goes right down as low as it can go, about -270 degrees celcius (270 degrees below). Eden asked why space is dark - it's because space is so empty and cold, there's nothing out there producing light except for the stars. On a similar note, Kayleigh, Ethan and Spencer asked why the sun is so hot - the Sun is a big glowing ball of super-heated gas, so hot you can feel it's warmth from millions of miles away, and it's powered by something called nuclear energy, a little like the energy they produce in nuclear power stations here on Earth. Jacob and Aryana wanted to know how big these stars are - the biggest are 2000 times bigger than our own Sun, but the smallest are about the same size as our planet Earth. Our own star, the Sun, is 100 times wider than planet Earth!
About Planets:
OK, now we're onto my favourite topic, the planets in the solar system. Lots of you wanted to know how big the solar system is - well, it's 3.7 billion miles to Pluto, which would take you 7000 years to drive in the car, but even that's not the edge of the solar system, as the effects of the Sun can be felt 25 times further out than Pluto. So the solar system is big, and there’s a lot to explore. Aryana wanted to know how old the solar system is, and we think it's about 4.5 billion years old. Some of the rocks on Earth (in Scotland, actually) are thought to be almost this old.
Ruby, Jude, Daisy, C. Sutton, Francesca and K. Galloway all wanted to know a bit more about Pluto. We used to call Pluto a planet (the ninth in the solar system), but over the past few years scientists have begun to realise that there are many more objects like Pluto out there in the distant solar system. We had a choice, we either call them planets (so you'd have to learn hundreds of names, rather than just the eight of Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune), or we call them dwarf planets, of which Pluto is the largest. We chose to call them dwarf planets, but that doesn't stop them from being very interesting places!
Anjan, Joe and Francesca asked about moons in the solar system, and just like dwarf planets, these can be really interesting places. Not all planets have moons, and most of the best ones orbit around the giant planets, Jupiter (63 moons), Saturn (62 moons), Uranus (27 moons) and Neptune (13 moons). My favourites are Europa (a moon of Jupiter with an icy ocean) and Titan (a moon of Saturn with a thick, smoggy orange atmosphere). Francesca wanted to know how many craters there are on our moon, but there are really too many to count, at least 300'000 we can see through our telescopes. On the same note, Freya, Kayleigh, William, Daisy and Aryana wanted to know how Saturn got its rings, and that's a really good question. We don't really know, but we suspect that an old moon got torn apart by some big collision, and the debris formed the beautiful rings.
Lots of you asked about the sizes of the planets, so here's a good way to think about it. If the Earth and Venus is about the size of a grape, then the Sun is about the size of a person, Jupiter is about the size of a grapefruit, Saturn an orange, and Uranus and Neptune the size of lemons. Joe asked why Jupiter is so big - it's because it sucked in lots of hydrogen and helium gas and got all puffed up when it first formed.
Eden asked why Mars is red - it's because the dust on Mars contains the same material as rust here on Earth, and it coats all the rocks to give the red colour. William asked about the comet Hyakutake, a comet that came near Earth in 1996 but won't return for thousands of years - it's about 2.6 miles across, but gives off a tail that extends for hundreds of thousands of miles across the solar system. William asked about the weight of the asteroid belt, the band of rocks that exists between Jupiter and Mars, and we think it weighs about 1/20th of the mass of our moon. Freya asked about Jupiter's great red spot, a giant swirling hurricane that's been raging for centuries, but I'm afraid no one really knows why it's red, as we don't know what the chemical is that's responsible for the red colour! But we do know the answer to her other question about Venus' poisonous clouds, as we know Venus' hot atmosphere contains lots of sulphuric acid droplets, which rain down like acid rain onto the surface. Not a nice place to go on your holidays!
Life:
The last section is about life. We said at the very beginning that the job of a space scientist boils down to two very simple questions - is there life somewhere else out there, and what made conditions just right here on Earth for you and me to be asking these questions? Joe asked how has Earth got life on it, and we think that the conditions were just right for us to get energy from the Sun (causes plants to grow for us to feed on) without being too hot (like Venus) or cold (like Mars) for life to get started. Kayleigh asked whether there is any life on Mars - all the Mars rovers and probes we've sent have suggested that Mars used to be a bit wetter, like the Earth, which might have been right for life to exist, but we've never found any evidence of even the simplest life forms, like tiny bacteria or viruses, so we think it's a dead world. Sakithya and Holly also asked whether there was life on the moon, and I'm afraid that the answer is definitely not - there's no liquid water or any atmosphere that would allow life to exist, so it's dead and cold up there.
Spencer asked if we've ever found any intelligent life forms? Not yet, but we're going to keep trying. In the last ten years we've discovered hundreds of planets around other stars, some of them are Earth-like, but still not quite right for life to exist. We're listening with giant telescopes, just in case there is any intelligent life out there sending signals to us, but no signs yet. But one thing's for sure - there are millions of planets out there, and if there's only life here on Earth, then the universe is a very lonely place.....
I hope that's answered some of your questions, and that it's encouraged you to keep on exploring!
Best wishes,
Dr. Leigh Fletcher,
Oxford University
April 2012"
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