A new astronomy column in BBC Knowledge Magazine
I’m very pleased to announce that I have a new column in the BBC’s excellent Knowledge magazine.
It’s called Above & Beyond and it’s where I’ll keep Knowledge readers up-to-date with what’s happening in the world of astronomy and space. There’ll be a certain practical element to the column too. So if there’s a planet worth looking out for or a meteor shower you just can’t miss, it’ll have all the details.
Knowledge is published, every two months, in the UK as well as in Bulgaria, Brazil, North America and Singapore. You’ll find my first column – all about the magical lure of Saturn – in the May/June issue, on sale this Wednesday.
New article – “Enceladus: water world”
Enceladus as seen by Cassini. Credit: NASA/JPL/Space Science Institute
Saturn’s moon Enceladus is a mysterious world. Measuring just 512km in diameter it should be a cold lifeless body, practically unchanged since its formation. Yet it isn’t. It’s very much alive. NASA’s Cassini spacecraft has shown that this remarkable moon’s surface has, in parts, been smoothed and altered in the geologically recent past. Images sent back by the probe show great fissures on its surface and, most spectacularly, vast plumes of icy material erupting from its southern hemisphere.
Now scientists studying Enceladus have come to some fascinating conclusions about what could lie beneath its icy crust. In a new article for Sky at Night Magazine I talk to the scientists working on the data from Cassini. I explore their findings which, incredibly, seem to point to a liquid ocean of water under the ice at Enceladus. The article also discusses the various mechanisms which could be creating the plumes. You can read the full story, “Enceladus: water world”, starting on page 68 of the May issue.
New asteroid article in Sky At Night Magazine
I have a new article in Sky At Night Magazine this month, about asteroids, addressing a topic that I’ve often wondered about and one I’ve heard asked about quite a lot recently (especially after things like this happen) — “why do we miss some spacerocks and why do we spot some of them so late?”. It turns out there are a few reasons, and thankfully there are several things that are being done about it. If you want to get the whole story though you’ll have to see pages 39-43 of the June issue.
New BBC S@N article — “Frenetic fields”
NGC 1275 as seen by Hubble and (inset) a magnetic active region on the Sun.
Credit: NASA, ESA and Andy Fabian (Univ. of Cambridge) & Hinode JAXA/NASA
I have a new feature article published in the January issue of BBC Sky At Night. It’s called “Frenetic fields” and is about magnetic fields in space and how they are responsible for shaping the Universe — everything from how they power the solar wind, to how they feed black holes and create galactic sculptures. You should be able to pick up the magazine in all good newsagents/bookstores early next week, as I’ve already seen it in a few places here in Bristol.
Milky Way’s black hole confirmed and more!
The stars at the centre of the Milky Way, in infrared. Credit: ESO/S. Gillessen et al.
My colleagues at ESO have just published a press release I worked on about a study into the black hole at the centre of our galaxy — the Milky Way. The release is the largest one I’ve done to date, and great fun to do too — not least because of the several fascinating intertwined stories within it. I’ll start with the big one though.
That is, a 16 year long study by astronomers (from the Max-Planck-Institute for Extraterrestrial Physics in Germany) has given us the best empirical evidence, so far, of the existence of truly massive black holes. Not only does the evidence verify the existence of these leviathan objects, it also shows that one is “beyond any reasonable doubt” hiding at the heart of the Milky Way, with a mass of some four million times that of the Sun. Here’s a section from the start of the release:
“By watching the motions of 28 stars orbiting the Milky Way’s most central region with admirable patience and amazing precision, astronomers have been able to study the super-massive black hole lurking there. The new research marks the first time that the orbits of so many of these central stars have been calculated precisely and reveals information about the enigmatic formation of these stars — and about the black hole to which they are bound.”
An artist’s impression of the orbits of the central stars. Credit: ESO
Incredibly, over the course of the study, one star (known as ‘S2′) was even able to make a complete orbit of the Milky Way’s hub. Yet it gets even better. Thanks to the observations we can now watch S2 whirl around (with all its companions) in actual infrared images from ESO’s telescopes, taken over the 16 years. The telescopes use adaptive optics to counteract the problems associated with trying to observe through Earth’s turbulent atmosphere. Observing in the infrared also allows the telescopes to penetrate the thick dust and gas of the Galaxy, and thus peer straight at these intriguing central stars. You can watch the animation of these real images in a (7MB) Quicktime video here. The motion of the stars has been sped up by just over 30 million times!
A frame from the video (see link above). Credit: ESO/ R.Genzel and S. Gillessen
If you want to get the full story you can read the whole press release here. There are some great videos to go with the article so be sure to have a look at them on the ESO webpage. And of course check out the second episode of the ESOcast (summarising the result), here. It’s great to see that, already, this fascinating result has sparked the interest of some major news outlets including here, here and here.
An illuminating blast from the Universe’s past
Last week ESO, the European Southern Observatory, released a press release about their observations of the gamma-ray burst GRB 080319B – one the brightest gamma-ray bursts ever seen – that occurred in March of this year. The press release covers the results of a new investigation into the burst. Astronomers who studied the burst have come to a startling conclusion about its orientation! From the press release:
“We conclude that the burst’s extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light,” says Guido Chincarini, a member of the team.
Above: Artist’s impression of GRB 080319B. Credit ESO
I was asked by the press team at the ESO headquarters, in Germany, to write the background story of that burst, including the many different observations made by telescopes around the world and how and when it appeared. The finished article has now been posted alongside the release as a two page pdf. You can read the ESO press release here and also download my feature story on GRB 080319B here (pdf download in link).
A prodigious pinwheel shines in the darkness
The stunning galaxy M83. Credit: ESO
My first press release for the European Southern Observatory has now been released. It accompanies what is, of course, the real interest in the story – a fantastic new image from the observatory’s Wild Field Imager camera. It shows the stunning spiral galaxy M83, arguably one of the most beautiful galaxies in Messier’s famous catalogue of deep sky objects. Here’s a snippet from the press release:
This dramatic image of the galaxy Messier 83 was captured by the Wide Field Imager at ESO’s La Silla Observatory, located high in the dry desert mountains of the Chilean Atacama Desert. Messier 83 lies roughly 15 million light-years away towards the huge southern constellation of Hydra (the sea serpent). It stretches over 40 000 light-years, making it roughly 2.5 times smaller than our own Milky Way. However, in some respects, Messier 83 is quite similar to our own galaxy. Both the Milky Way and Messier 83 possess a bar across their galactic nucleus, the dense spherical conglomeration of stars seen at the centre of the galaxies.
You can read the full press release and download a hugggeeee version of the image here.
Mars madness, Hubble and some book news
I’ve had several emails, in the last two weeks or so, asking when Mars is going to appear the size of the Full Moon this August. I was going to post something up about this, however it seems Phil has been asked about it too. So I’ll leave the Bad Astronomer himself to debunk it, but in short this is absolutely not true and will not happen. It’s an email/Internet hoax that has been going around the Internet for the last few years. Unfortunately it seems to rear its ugly head every August.
Mars’s mean distance from the Earth is about 225 million kilometres meaning that even through a powerful amateur telescope it will only appear as a disc showing (at best) the polar ice caps and a few dark surface markings. At the moment Mars is not well placed for viewing as it’s far too close to the Sun (as seen from Earth). As the Earth and Mars travel through their orbits around the Sun, the distance between the two planets changes dramatically. So some years Mars does come closer to us and telescopic views do show it much better at these times than others. Yet even at its closest (56 million km) it only appears with the naked eye as a bright ‘star’ with a ruddy tint, certainly nothing like the diameter of the Moon which is a mere 380,000 km from Earth.
Anyway on to much more sensible things – like a reminder of the talks I will be giving in the next few weeks! On the 2nd September I will be talking at the Wiltshire Astronomical Society, details are here. So if you are in the region come along and say hello. I will be giving my talk on the science behind Hubble’s greatest images entitled “Not just pretty pictures”. Then on Saturday 6th September I will be giving a lecture (starting at 2:45 pm) at the 2008 Herstmonceux Astronomy Festival, again with the my talk on the science in Hubble’s images. You can find out about the festival here as well as information on the main Saturday lectures here.
Finally then a bit of random book news. Yesterday I finished editing the manuscript and tomorrow will be sending off my final draft of the book to the publisher’s in New York. It’s quite exciting for me, as the next time I see it it will probably be in the form of the galley proofs. Lastly (I mean it this time) If you’re in the shops this week the new issue of Sky At Night magazine is out. You can read my cover feature on “The Next Supernova”, to see which Milky Way star astronomers think might be next to go supernova.
All done!
For the last week or so I have been editing the first full draft of the manuscript for my book. I finished writing about ten days ago but didn’t post anything, partly due to tiredness/forgetting and partly due to the deadline that is fast approaching! However from the picture on the left you can see that I am just over halfway through the proofing/editing stage.
I was prompted to post to say I had finished by Keith Mansfield (thanks Keith!) who is author of Johnny Mackintosh and the Spirit of London (and tipped as the next J.K Rowling). Keith also has a very nice blog here, including posts on astronomy and space. So all being well, by around this time next year it will be the published book sitting on my desk and not my scribbled-on draft!
50 wonders you must see before you die
I have the cover feature on the new issue (August) of BBC Sky At Night magazine. It’s about the fifty sights you must see in the night and daytime sky, related to astronomy of course, before you die.
It’s ten pages long and there are some amazing celestial views that even a seasoned astronomer might not have seen yet! August’s issue is packed full of great features as well, plus all our regular slots, so be sure to grab a copy when it hits the shelves next week. Stay tuned to the blog for some more big news coming in the next few days.
Cover image courtesy: BBC Sky At Night magazine
Now wash your wheels!
Clandestine agents and heroic citizens of blockbuster sci-fi movies are often portrayed as defending the Earth from the alien miscreants of the Universe. Blasting slimy green extraterrestrials might be great cinema, but it doesn’t always represent the shrewdest of scientific moves. That’s because whilst the chances of ne’er-do-well space-faring aliens wandering around our towns and cities can be safely relegated to science-fiction, the reality is that it’s the Universe, not us, that needs defending from visitors from Earth.
So how do we clean our spacecraft when we send them out into space? To answer that question here’s the result of an interview I did with NASA’s Planetary Protection Officer a few months ago. This concern is particularly relevant given the current mission of NASA’s Phoenix Mars lander and that of the Mars Exploration Rovers, who are studying locales on the Red Planet that might be hospitable to life.
Ever since the first robotic missions to the planets we’ve also been inadvertently sending small amounts of microbes up there too. It wasn’t until the last few decades (when we began scouting for microbial life elsewhere in the Solar System) that this started to become a major headache for space agencies around the globe. The last thing we want to do in our search for life in the Solar System is discover the disastrously familiar sign of life which has piggybacked its way millions of kilometres from Earth.
Spirit & Opportunity were only allowed to take a certain level of spores with them. Courtesy: NASA/JPL/Caltech.
Today the responsibility for keeping NASA’s spacecraft clean (and in some ways protecting any alien life in the Solar System) falls on its Planetary Protection Officer Dr Catharine Conley. Her job is to see that NASA spacecraft are kept free from microbes from Earth that might be spread into space by our space-faring endeavours…well almost. It might surprise you that already we’ve let countless microbial ‘spores’ into the Cosmos. “There were probably viable spores on spacecraft that were launched over the past few decades, however we are quite careful to monitor the trajectories and subsequent disposition of the spacecraft, so that we know what has happened to them,” says Dr Conley.
The reason these microbes got out is that it’s not yet possible to completely sterilise a spacecraft before an interplanetary voyage. But all is not lost as Dr Conley explains. “From everything we have seen so far, it’s quite unlikely that any spores carried on those spacecraft have actually landed in a place where they might grow.”
So how exactly do you clean a spacecraft? If you’re now imagining a multi-million dollar probe being lathered in disinfectant by a group of fastidious sponge brandishing scientists, then you’re in for a shock. The reality is much more bizarre. “A variety of cleaning procedures are used, depending on the material requiring cleaning” explains Dr Conley. The aim is to make sure that the number of microbes on the spacecraft does not exceed pre-determined levels. Of all the methods used, the one that has thus far proved most effective is ‘dry heat’ sterilization. Put simply the spacecraft is baked in a giant oven at temperatures of several hundred degrees Celsius, killing most lurking micro-organisms.
Other methods such as swabbing exposed surface panels with alcohol are sometimes used and NASA is also developing other new methods to reduce the amount of potential microbial contaminants. One proposed method involves firing cold plasma at spacecraft, zapping any microbes. Another involves dousing any bacterial stowaways with hydrogen peroxide vapour. “The type of mission and the conditions we find at other planetary bodies are what dictates the level of protection,” explains Dr Conley. Yet, according to Dr Conley, in this article in NASA’s Astrobiology magazine these important protection regulations might generate complications when astronauts want to start exploring worlds like Mars; worlds which might harbour primitive life.
For the most part Mars’ surface is thought to be inhospitable to life, so astronauts will most likely be allowed to roam free over large areas of the barren ochre surface. But what if we actually want them to look at and explore the sites where living microbial life might be found?
That might not be so easy to do warns Dr Conley. “Humans will not be allowed to contaminate locations where Earth life might survive before we have a chance to study them sufficiently for signs of extraterrestrial life,” a proposition that is as reasonable as it is frustrating. If life is present on the red planet then it looks like it will be the electronic eyes of a rover, a wheeled robotic ambassador, which will glimpse the first signs of it. With the future of whole worlds at stake then, scientists can’t risk forgetting to wash their rovers’ wheels.
Book news (Part II)
Today I began work on the final chapter of the book. It’ll probably take about 4 weeks of writing to complete as I’ve also got to write the captions for the images too – but the point is that I am nearly finished! The chapter I’m currently working on isn’t actually the last chapter, it’s an earlier one. It’s also one of my favourite subjects so that should make this last bit quite fun to write. I’ll keep the blog updated with how it’s going but if I don’t post for a while you’ll know what I’m doing!
Where do comets really come from?
I have a new feature in May’s BBC Sky At Night magazine (out in the shops early next week) entitled “Where do comets really come from?”. It’s about how new results from the NASA Stardust mission are unveiling new insights into the origin of cometary material.
Left: Comet Wild 2. Credit: Stardust/JPL/NASA
The Carnival of Space no. 49
Hello and welcome to the 49th Carnival of Space. I’m really pleased to be hosting the carnival this week as we have some brilliant stories for you, thanks to some great writers and bloggers. This is where after a week of hard work you can now sit back and get your full dose of astronomy related news and views, finding out what the blogosphere has had to say about the Universe, in the last week. Don’t forget to check back soon and subscribe to the RSS feed on the right to keep up-to-date with the site. So, without further delay let’s begin…
The start of this week’s carnival takes on a distinctly stellar theme. Fraser at Universe Today responds to a superb astronomical question from his young daughter that I am sure we have all wondered about at one point or another.
Towards the end of March a massive Gamma Ray Burst (or GRB) was seen in the night sky. It was the brightest most distant GRB to date and one that was so bright it was visible to the naked eye! Dr. Ian O’Neill on Astroengine asks whether a peculiar type of star called a ‘Wolf-Rayet star’ could be responsible.
Complementing this nicely, Ethan at Starts With A Bang! poses the question “Do all stars eventually explode?”. The Hubble Space Telescope has certainly found a star that will eventually explode. In fact, as Phil on the Bad Astronomy blog says, Hubble astronomers have caught a supernova in a galaxy right at the point it is beginning to ‘go off’.
If a star is big enough when it dies it can form a black hole. Alan Boyle, of Cosmic Log, explores how new simulations of black hole interactions are showing the disparity between Newton’s and Einstein’s gravitational theories.
With the release of the new Indiana Jones film a matter of months away, Rob carries out his own astronomy related archaeological investigation of a prehistoric site in Alabama in the USA, over at Orbiting Frog. Though as far as I can tell didn’t find any rats, sacred relics or hidden treasure!
Meanwhile Chris Lintott reports from the Royal Astronomical Society’s National Astronomy Meeting (on the NAM blog) on the discussion held in Belfast on the current funding situation of UK astronomy and particle physics.
One of the big tasks for those returning to the Moon and then looking forward to Mars is how we are going to carry out day-to-day tasks, like exercise and growing plants for food etc. Ken Murphy at Out of the Cradle explores how we might be able to grow plants in the lunar soil in part one of his post ‘Of a garden on the Moon’. Let’s hope when we get to the Moon or Mars they also have Internet access.
For those of you that can’t get enough of Mars though the Martian Chronicles team have another update on the Opportunity Mars Exploration Rover, including a stunning panorama of the martian ‘Cape Verde’ rocky outcrop. When we do get to Mars maybe we will move our bases around with giant robots, Colony Worlds investigates what that might involve. And if you are new to the excitement of martian exploration then Stuart has some tips on how to survive your first Mars landing. Meanwhile, Bill Dunford at ridingwithrobots.org has an incredible animation of Victoria crater taken at different times (and illuminations) during a martian day.
Centauri Dreams skeptically ponders whether the SETI program should search for extraterrestrial constructions known as Dyson Spheres, and asks if any other potential civilizations around other stars think like we do. Clearly when we humans want to venture out into space we are going to have to develop new technologies. Next Big Future has an article on how carbon nanotubes may be used in future space power and propulsion system whilst Henry Cate reports from Space Access 2008.
Music of the Spheres blogs about the 2008 Space Expo at the New England Air Museum. Even though the Space Shuttle simulated flights made by visitors to his stand might not have had the smoothest landings that NASA has seen, their educational value was worth it all.
A Mars Odyssey also brings us up-to-date on the launch of the Soyuz from Baikonur on the latest ISS Expedition 17.
Well that’s about it for this week’s Carnival of Space, remember that you can find a list of all previous carnivals on the Universe Today website.
Top: Artist’s impression of a GRB. Credit: NASA
Middle: Hubble has spied an exploding star in this galaxy (NGC 2397). Credit: NASA, ESA & Stephen Smartt (Queen’s University Belfast, UK)
Lower middle: Artist’s impression of a MER. Credit: NASA/JPL
Bottom: Touchdown for the Shuttle. Credit: NASA
Exoplanet NAM post
I’ve written up a new post about today’s NAM announcement of the discovery of an embryonic exoplanet. The first paragraph is below:
“Astronomers here in Belfast have just announced that they have discovered what they believe to be the youngest ever planet observed. So young that it may have not completely formed yet. They used radio telescopes in the UK (the MERLIN network) and in the US (the VLA) to study the star system of HL Tau, a star in Taurus about 520 light years from Earth”
You can read the full article and see the pictures here.
NAM day two
Well today is day two of the National Astronomy Meeting. I’m going to be posting any future NAM news I have on the NAMblog so be sure to check there for the latest NAM news. Today has kicked off with some great plenary session lectures on the acceleration of the Universe and the dynamic nature of the magnetic fields on the surface of the Sun. Chris and I have posted two takes on Dr Brian Schmidt’s ‘Measuring cosmic acceleration’ talk, why not take a look.
NAM news 2: Massive starburst in the early Universe
Dr. Scott Chapman from the Institute of Astronomy in Cambridge has just presented the latest results from a collaboration between the MERLIN UK radio telescope array, Keck (at optical wavelengths), the VLA in the US and the Plateau de Bure submillimetre observatory in France. The results show that there was a group of galaxies in the early Universe that experienced an incredible burst of star formation about 2 billion years after the Big Bang. This phenomenal burst of activity was observed in galaxies that were shining a mere 3 billion years after the Big Bang and is thought to have been vastly more dramatic than any star formation we see nowadays.
Remarkably it was only until relatively recently that astronomers detected a similar gathering of sub-mm galaxies in the early Universe. These galaxies are particularly faint in optical wavelengths but very bright in the radio wavelengths. Instruments like SCUBA mounted on the James Clerk Maxwell Telescope (JCMT), on Mauna Kea in Hawaii could see the sky in sub-mm wavelengths and so could detect them; allowing astronomers to investigate their nature. Yet astronomers believed that these galaxies were only part of what was going on (star-forming wise) in the early Universe, because SCUBA was good at looking at relatively cooler sub-mm galaxies.
Now, these new results from the collaboration of many telescopes do indeed show a gathering of slightly warmer galaxies, not altogether different from those spied by SCUBA, undergoing dramatic star formation. The observations indicate that these galaxies are surrounded by vast clouds of gas. That gas, the astronomers argue, will keep the star formation going at a tremendous rate for “hundreds of millions of years”.
You can see images from the results and a very cool video here.
NAM news 1: SuperWASP strikes (10x)
One of the results that has just been released from the National Astronomy Meeting is that the SuperWASP exoplanet hunting project has discovered an incredible 10 new exoplanets. SuperWASP is an ingenious project which uses eight sensitive CCDs on eight wide field telescopes to monitor a huge number of stars in the night sky. It can record an incredible 100,000 stars in one image! What they are looking for is the tell-tale blink (more of a temporary and gradual dimming) of a star’s light which indicates a planet passing in front of the star.
This method of looking for the dimming of a star is known as the ‘transit method’ of exoplanet hunting. There have been around 270 exoplanets discovered so far and 45 of those found have been via the transit method. What’s even more impressive is that of those 45, 15 were detected by the SuperWASP instruments. The new planets that the robotic telescope has discovered range in masses of between half and just over eight Jupiter masses.
If you haven’t heard of the SuperWASP project or want to find out more then have a read of their pages here.
Above: The SuperWASP-South instrument array
Credit: SuperWASP
Hubble finds methane on an exoplanet
The Hubble Space Telescope has recently found the organic molecule methane on the extrasolar planet HD 189733b. Here’s a section of the ESA press release below.
“Under the right circumstances methane can play a key role in prebiotic chemistry – the chemical reactions considered necessary to form life as we know it. Although methane has been detected on most of the planets in our Solar System, this is the first time any organic molecule has been detected on a world orbiting another star”
With an atmospheric temperature of around 900 degrees there certainly isn’t going to be life (at least as we know it) on HD 189733b. The importance of this observation is more that it is “proof that spectroscopy can eventually be done on a cooler and potentially habitable Earth-sized planet orbiting a dimmer red dwarf-type star” says Mark Swain who led the team that made the discovery at NASA’s Jet Propulsion Laboratory (JPL).
I saw this exciting news come in when I was working with the Hubble group in Germany and I began scripting a Hubblecast to cover the result. To see the finished piece visit the ESA Hubblecast no.14 page here.
Above: An artist’s impression of HD 189733b around its parent star.
Credit: Credit: ESA, NASA and G. Tinetti (University College London, UK & ESA)
Britain’s Moon shot
I have a new feature article (my first cover feature!) in April’s issue of BBC Sky At Night magazine, which is in the shops on Tuesday 18th March.
The article covers the proposed MoonLITE probe, a UK mission to send a small spacecraft to the Moon deploying four missiles to study the lunar surface. The missiles (or ‘penetrators’ as they are actually called) will impact the surface and remain there working for about a year. They will create a seismometer network as well as carry out geological and chemical analyses of the lunar surface. It’s a fascinating proposal. You can get the full story and read several expert interviews in the article.
You shouldn’t fail to miss the cover in the shops, the graphic designers and illustrators who worked on this article have really brought the story to life. So if you do spot the magazine grab a copy and find out how the UK may soon be joining the return to the Moon!
N.b. If you are in south-east England on Wednesday (19th March), at 10:30am, tune into BBC Radio Kent as I will be speaking live with Dominic King about MoonLITE. If you are in or around Cumbria I will be talking live to Ian Timms about the mission on BBC Radio Cumbria at 12:40pm the same day.
Farside radio astronomy one step closer
For a long time astronomers (specifically radio astronomers) have wanted to place a telescope on the Moon. Now it seems that that desire is slowly becoming a possibility. NASA recently announced how it was backing a series of studies to investigate potential experiments for its ‘Next Generation Astronomy Missions’. Included in that backing is one proposal from the Massachusetts Institute of Technology to build a small radio telescope array on the Moon’s far-side.
Radio telescopes are really important tools for probing the Universe. All sorts of objects emit radio waves; quasars, very hot gas in the space between the stars, electrons rapidly whirring around in magnetic fields as well as planets to name but a few. On Earth radio astronomy has been at the forefront of astronomical research for decades. Indeed many of the great discoveries of modern astronomy have been made thanks to the use of radio telescopes; for example the radio telescope (MK1A) at Jodrell Bank Observatory in the UK discovered the first gravitational lens amongst its many great accomplishments.
But there is a problem with doing radio astronomy from Earth. Radio signals from astronomical objects are extremely faint; something that makes observing radio sources tricky even on a good day. But radio waves, of course, don’t just come from the sky. Radio stations, satellites, Wi-Fi networks and many other man-made sources all emit vast amounts of radio waves that are much more powerful than those coming from space. With this ubiquitous fog of radio waves often ‘spilling’ into the frequencies that astronomers observe in (combined with the fact that the Earth’s ionosphere blocks certain radio signals) it’s a wonder we can observe anything emitting radio waves in space; sorting the proverbial radio wheat from the chaff is no easy task.
What radio astronomers really need is something to block all the ‘noise’ coming from the Earth. Something like a massive shield…something like…the Moon. By locating radio telescopes (or groups of smaller telescopes called ‘arrays’) on the lunar ‘farside’ the telescopes are hidden from the radio noise from the Earth, since the farside is always in the radio ‘shadow’ of the Moon, plus they don’t have the Earth’s ionosphere to contend with!
MIT’s proposed telescope will consist of hundreds of small instruments set up across about 2 square kilometres to studio low frequency radio waves. The telescopes will be arranged by robotic machines and they don’t have to be that accurate since the wavelenghts that the array will study are fairly long. The array will probe some of the least well known periods of the Universe’s early history as well as looking at space-weather from the solar wind, radio emissions from the planets and possibly even galaxies too.
I’m going to be talking to Dominic King live on BBC Radio Kent at 10:30am tomorrow morning about the ambitious plans for these lunar observatories so if you are in south-east England tune in!
Above: ‘Farside’ radio telescopes will be able to tell us more about periods in the early Universe, earlier than the HUDF (pictured).
Credit: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team
Odyssey’s end in sight for Ulysses
After just over seventeen years in space the Ulysses space probe looks as if its mission is drawing to a close. According to the European Space Agency Ulysses is beginning to show the signs of age, after nearly two decades touring the Solar System in orbit around its main interest – the Sun. The spacecraft is in a somewhat peculiar six year orbit around the Sun which takes it at one extreme flying right out to Jupiter and at the other extreme whirling over the Sun’s polar regions.
Ulysses has scrutinized the Sun in great detail over its seventeen or so years, telling us about the solar wind (the stream of charged particles emanating from the Sun), the Sun’s powerful magnetic field as well as how the Sun’s chromosphere and corona interact. One of Ulysses’ most interesting finds was that the solar wind at the poles of the Sun is emerging much faster than at the equator (with speeds of 750km/s and 350km/s respectively); and that the polar winds dominate about 2/3 of the heliosphere (the vast ‘shield’ around the Sun created by the solar wind). The probe, which was launched from the Space Shuttle’s cargo bay in 1990 has also studied Jupiter’s magnetic fields and the plasma environment around the giant planet.
So why is Ulysses dying after all these years? Well the probe itself is powered by the radioactive decay of a special isotope of plutonium. This decay slowly releases heat which the probe’s on-board technology converts into electricity. This in turn powers heaters, the science instruments and the communication antennae that are needed to send data back to Earth. However over time the radioactive isotope decay levels drop meaning that so to do the amounts of electricity produced.
This poses a problem for the craft because as it ventures out into space it needs its on-board heaters to keep the spacecraft at the right temperature. If they don’t and the craft’s temperature drops below 2°C then the probe’s fuel hydrazine (where have you heard that before) will freeze solid. It reminds me a bit of the lizards on David Attenborough’s incredible new BBC series ‘Life in Cold Blood’. They either need the Sun to warm them or find some heat of their own, otherwise they will freeze and die.
The scientists working with the Ulysses probe realised that if they didn’t do something the power levels would drop so much that the heaters and the science instruments would stop working – freezing the all important fuel. So in January they turned off the main transmitter that was sending data back to Earth in the hope that the re-routed power would go to the heaters and the science packages; keeping the hydrazine liquid. Unfortunately when they wanted to turn the transmitter back on to see if it had worked nothing happened. Now it seems Ulysses’ fuel will freeze as the probe cools in the vacuum of space to that crucial 2°C, bringing with it the end of an illustrious mission. Thankfully though there are many missions which are taking up Ulysses’ baton like SOHO, Stereo, Trace and Hinode. So solar science will be continuing into solar cycle 24, long after little Ulysses ends.
Above: An artist’s impression of the Ulysses probe
Credit: ESA
Hubble finds a COSMOS of gravitational lenses
Hubble Space Telescope scientists have recently announced that they have discovered 67 gravitational lenses lurking in images taken for a survey of galaxies. Hubble has spotted the gravitational lenses as part of the COSMOS survey into large scale structure of the Universe. The scientists have found some really cool lenses like the ‘Einstein Ring’ on the left. The results show that if the number of lenses seen by Hubble in this survey is typical of large sections of the sky then there could be hundreds of thousands of this type of gravitational lens across the whole night-sky!
This is one of the press releases that I worked on whilst in Germany last year. If you want to read the full story check it out on the ESA Hubble website here. As an aside it’s great to see Atlantis landed safely. Columbus is now installed on the International Space Station which is now looking incredible. The Columbus module is the one jutting out to the right hand side of the line of vertical modules in that image.
Above: This incredible ‘Einstein Ring’ captured by the Hubble Space Telescope is the product of a rare line-of-sight alignment of massive lensing galaxy, background galaxy and Hubble itself.
Credit: NASA, ESA, C. Faure (Zentrum für Astronomie, University of Heidelberg) and J.P. Kneib (Laboratoire d’Astrophysique de Marseille)
Save the skies…
…save the world. That’s the title of my new article in March’s issue of BBC Sky At Night magazine. In the article I discuss how the aims of astronomers and environmentalists have converged. I argue that if we can reduce our wastage of light, create more efficient lighting fixtures and get councils and local authorities to dim or at least reduce their lighting usage then we can not only save the night skies but reduce our carbon emissions. Hopefully in doing so we can be a little less harsh on our environment. If you are concerned that these sorts of measures may result in a wave of criminals and ne’er-do wells sweeping the streets then it’s worth reading the material on this page on the Campaign for Dark Skies’ website.
