The BBC is running a video of Yves Rossy, a Swiss man who jumped from a plane and then flew using his homemade jet-propelled glider. The image above shows a previous version of the glider, which only has two jet engines. The model flown this week used four. Mr. Rossy, has been gathering fame on the web for some time, and this stunt will no doubt be circulating for some time. Once he produces a commercial product, I will stop whinging that the future is not here yet.
Mars is back, and doing things it shouldn’t! Our warring friend started May in the constellation Aquarius, it then moved into Pisces on the 8th. For a really cool thing (if you’re utterly geeky like me) you should look up between the 24th and 29th when it cuts across the corner of Cetus, the constellation of the Whale. Since Cetus isn’t in the zodiac, this is nice sight and hopefully befuddles all those silly astrologers everywhere (It then goes back into Pisces again.)
The only problem you’ll have is that Mars is very low-down in the south-eastern dawn skiey. You also have only a 15 minute window of observation, from about 4.45am, before the sky is too bright anyway. Give it a go or just lie in bed and ‘know’ that Russell Grant is spitting tacks.
Also, Chris Lintott has a link to some lovely Mars images over on his blog.
A while ago I posted about the Bullet Cluster, and an image which seems to reveal the dark matter within it. Now a new image from Hubble seems to do the same thing for the galaxy cluster CL0024+17.
Now I am personally rather sceptical about the validity of images such as these, although I feel sure that we will see many more of them in the coming years. ‘Showing’ dark matter sounds to me like a dangerous business. It is, after all, dark. I would argue that releasing such images is detrimental to science and astronomy more specifically. To fool the general public into believing that something exists before you are sure of it yourself is not good science.
Now it may be beneficial to model dark matter in the way shown in these images, and this could lead to a better understanding. To release this sort of thing without warning as to the subjective nature of its content is not fair on those who would simply believe it as a photo like any other. After all how sure can anyone be that what is shown here is anything real at all? It is like deducing the nature of the wind from the way birds fly.
There is more to it that just that though. I know so many people who have no clue that many of the images they see from space are false-colour, for example. I also have to explain to people everytime I shown them Andromeda through a telescope, and look back at me confused, that the images they see from Hubble and other big observatories are enhanced, essentially doctored, to make them prettier. Do you think they will understand that this dark matter ring is simply a mathematical deduction? Will they even care?
Maybe I’m overreacting, but I do believe that one of the jobs of any scientist is to report back their findings to the public at large, who ultimately fund them. The PR guys need to get educated as to what this image and the ones that are surely coming our way soon, really mean.
Dark matter is still not a subject that we know much about. Its a mystery - and that is one very good reason it is so interesting. We cannot photograph it because we don’t know where it is. Gravitational lensing tehcniques can begin to help us locate it but don’t let’s be fooled by what the com puters give us at the end of the day. If we start to believe these images are real simply because they look real we will have strayed off the correct path and begin putting garbage into our theories. This is, as my supervisor always says, never a good thing because you end up with rubbish results; garbage in, garbage out.
You can read more over at Astronomy Picture of the Day and the Bad Astronomy Blog.
This week’s Astrolunch talk was given by Vanessa Stroud from the Faulkes Telescope Group. As is always the case though, this talk was unrelated to her PhD research and she was talking about a new example of a certain type of nova that has been found using GalEx, the Galaxy Evolution Explorer.
This composite image shows Z Camelopardalis, or Z Cam, a double-star system that features a collapsed, dead star, called a white dwarf, and a companion star, as well as a ghostly shell around the system. The massive shell provides evidence of lingering material ejected during and swept up by a powerful classical nova explosion that occurred probably a few thousand years ago.
The image combines data gathered from the far-ultraviolet and near-ultraviolet detectors on NASA’s Galaxy Evolution Explorer on January 25th, 2004. The orbiting observatory first began imaging Z Cam in 2003.
Z Cam is the largest white object in the image, located near the center. Parts of the shell are seen as a lobe-like, wispy, yellowish feature below and to the right of Z Cam, and as two large, whitish, perpendicular lines on the left.
Z Cam was one of the first known recurrent dwarf nova, meaning it erupts in a series of small, “hiccup-like” blasts, unlike classical novae, which undergo a massive explosion. That’s why the huge shell around Z Cam caught the eye of astronomer Dr. Mark Seibert of Carnegie Institution of Washington in Pasadena, California - it could only be explained as the remnant of a full-blown classical nova explosion. This finding provides the first evidence that some binary systems undergo both types of explosions. Previously, a link between the two types of novae had been predicted, but there was no evidence to support the theory.
The faint bluish streak in the bottom right corner of the image is ultraviolet light reflected by dust that may or may not be related to Z Cam. Numerous foreground and background stars and galaxies are visible as yellow and white spots. The yellow objects are strong near-ultraviolet emitters; blue features have strong far-ultraviolet emission; and white objects have nearly equal amounts of near-ultraviolet and far-ultraviolet emission.
There is a lovely high-quality video showing how this sytem works which can be downloaded here.
This post was created from a NASA press release which can be found here.
I don’t know how they found out about it but someone at Uni today showed me this rather funny Google Maps result. Ask for directions from somewhere in the USA to somewhere in Europe and you are told how to do it, without flying. I searched for Cardiff to New York and if you check our point 34 on the image above or this link then you’ll see why I found it funny.
I have started reading The Feynman Lectures in Physics. Overall there are three volumes to collection. They were created from a two year course in physics given by Richard P. Feynman, a professor at Caltech and a Physics Nobel Prize winner. I am finding the books not only refreshing (they have almost no equations) but also entertaining and so very useful. I am learning physics over again in some areas and learning truths I never really understood before.
I am current on chapter 17 (of 44 in this volume) and have bee making notes. In the spirit of sharing and of consolodation for my own sake, here some things I now know.
On Atoms
An atom is about 1 or 2 Angstroms across in size. An angstrom is 0.000000000 1 metres and this makes atoms comparable in size to one hundredth of the wavelength of light.
If you made an atom the size of a room then the nucleus, containing the protons and neutrons would be a mere speck of dust barely visible in the centre.
If an apple were magnified to the size of the Earth then the atoms in the apple would now be the size of the original apple!
You can burn a diamond in air.
CO (Carbon Monoxide) is essentially a picture of itself.
On the Fundamentals
Think of a game of chess. you can watch the game and you might grasp a few of the rules. You might see that Bishops move diagonally or that pawns move only one step. You will however not necessarily be able to play just by watching. Why one player makes a move or another responds will seem a mystery. This is akin to the laws of nature, i.e. physics. We can know the rules (gravity, kinematics etc) but not therefore how to play.
Some of greatest moment sin science have been when two or more seemingly unrealted topics are shown to be related and intertwined. some examples are quantum mechanics and chesmistry; electricity, magnetism and light; heat, temperature and mechanics.
Helium was discovered on the Sun before it was found on Earth. This is why is got its name; Helois was the Roman god of the Sun.
6 fundamental things are always conserved. That is to say that these things are never created or destoyed spontaneously but simply moved around the universe. These conservation laws tell us a lot about how nature works. The six conserved quanities are energy, linear momentum, angular momentum, baryons, leptons and electric charge.
There is enough energy is 1000 litres of running water to power the entire of the United States. It is up to physicists to figure out how to liberate it so that the world can be freed of its need for energy. It can be done!
On Time and Distance
Does time exist on an ever shorter scale? A day contains 24 hours, which in turn contains 60 minutes of 60 seconds a piece. How far down can we go and does it make sense to speak of times which cannot sensibly be thought about?
We can use carbon dating to pin something down to being more than 100,000 years old, ut not much further. Uranium on the other hand can reliably date things back for billions of years, so long as there is rock there that has remained unchanged for as long. The oldest rock on the Earth is over 4 billion years old!
Atomic clocks will soon be accurate to within one second in the age of the entire universe.
On Gravity
If you fire a bullet it falls at the same rate as anything else but obviously moves a very long way across the surface of the Earth in the same time. If you could fire a bullet at 5,000 miles per second then it would never hit the floor as the Earthb would curve away benath it as fast as it could move. The bullet would be in orbit.
The tide come sin 50 minutes earlier each day.
Due to the width of the Earth’s orbit around the Sun, the light travel time from planets like, Mars, Jupiter, Saturn etc varies by almost half an hour. This fairly long period of time has astronomers very confused in the 17th century when their predictions for the orbiting periods of Jupiter’s moons kept appearing to be wrong by anything up to half an hour. Eventually this led them to thi k that light may have a finite speed and so the first estimates for the speed of light, c, were made in 1656.
Thats all for now…
I’ve just had another ‘Philiosophy of Science’ meeting where we were talking about social responsibility. The topic of the Manhattan Project came up and the Hiroshima and Nagisaki bombs as well as the Challenger Distaster and Columbia. We ended up discussing how many people die every year globally and how it compares to the number killed in individual events. The whole ‘how many people die everyday’ thing got me Googling and I found this:
http://esa.un.org/unpp/p2k0data.asp
Its a site from the United Nations that gives you lots of population stats including, for the 2000 to 2005 period:
Deaths ~ 150,000 people/day
Births ~ 350,000 people/day
Net Popoluation Increase ~ 200,000 people/day
In 1950 the figure for net change was approximately ~ 110,000 people/day. So just to place it into a rather peculiar (and possibly perverse) context, the Hiroshima bomb, which killed around 140,000 people, therefore in a single act reduced the global population in one day. I wonder when else this has happened in history?
It means that 9/11, was merely background noise in mortality terms. Car accidents on the other hand kill 1.2 million annually (~3,300 daily) which means that the car itself (or rather the driving of it) is the equivalent of having a World Trade Centre-esque attack every single day. So I am lead to ask where’s the War on Cars?
The point is not to marginalise death but rather to get people talking about it context. I find it very odd that quite so many people die every day. Yet this is obvious and natural. The Challenger distaster which killed seven people had a national impact, yet that many people die globally every three minutes.
I’m confused, which I’m liking more and more these days…
I’ve just spent the weekend in Rome. In fact I had one of the best holidays ever running around the Italian capital and generally being silly with my friends. We also visited the Vatican, naturally, and so upon returning home I thought I should do a Roman Catholic Orbiting Frog post.
So what did the Pope ever do for Astronomy? Well quite a lot it seems. There is a Vatican Observatory outside of Rome which operated for many centuries. Its origins can be traced back to the 16th century and research is still done there today.
The observatory was first thought of by Pope Gregory XIII who had a penchant for astronomy. It is actually him that grabbed my attention when looking up the history of the papacy’s astronomical ties since Gregory himself enacted something which has since affected most of the world today.
A thousand years ago, give or take a century, the Roman Empire created the Roman Calendar. It consisted of ten months (Martius, Aprilis, Maius, Junius, Quntilis, Sextilis, September, October, November, and December) in a year of 304 days. After December had finished there would be a period of Winter in which there were no numbered days until the King decided it was time to start over, based on thr advice of his astronomers.
One king had the bright idea to insert a specific Winter and so introduced January and February, although February came first for over 200 years! Then in 46 Bc, another 400 years later, Julius Caesar formalised the calendar (remaning some Months along the way in the form of July and August) into what is called the Julian Calendar. This was a system of years with 365 days and then every fourth year (a leap year) 366.
By the time Caesar did this, the months and the season were no longer at all in sync. He had to add in 90 days to the year 46BC in order to resynchronise them. But even this new system - the height of technological innovation at the time - wasn’t quite right.
So it was that in 1582 AD, Pope Gregory XIII devised a way to sort the calednar out once and for all. What he came up with was a system based on a cycle of 400 years comprising 146,097 days, in a year of an average length of 365.2425 days. The Gregorian calendar, as it became known, is a modification of the Julian calendar in which leap years are omitted in years divisible by 100 but not divisible by 400. By this rule, the year 1900 was not a leap year (1900 is divisible by 100 and not divisible by 400), but the year 2000 will be a leap year (2000 is divisible by 400).
Pope Gregory’s calendar was constructed to approximate the tropical year, which is the true time taken for the Earth to complete one orbit around the Sun.
The Julian calendar was switched over to the Gregorian starting in 1582, at which point the 10 day difference between the actual time of year and traditional time of year on which calendrical events occurred became intolerable for framers and the general life. Pope Gregory decreed that the day after October 4th 1582 would be October 15th, and so the Catholic countries of France, Spain, Portugal, and Italy complied.
The Protestant German countries adopted the Gregorian reform in 1700. By this time, the calendar trailed the seasons by 11 days. England and what would become American finally followed suit in 1752, and Wednesday, September 2nd, 1752 was immediately followed by Thursday, September 14th This traumatic change resulted in widespread riots and the populace demanding “Give us the eleven days back!”, according to Vardi’s ‘The Gregorian Calendnar’.
Makes daylight savings seem like child’s play.
Sunspot 923
Originally uploaded by fdecomite.
I love this picture. It comes from the Flickr Astrophotography group, which is featured in the sidebar of Orbiting Frog. I didn’t know that one could capture a sunspot during a sunset but it seems you really can.
Go and check out fdecomite’s photos and you’ll find more from the same sunset as it progresses along. It makes a great set of photos in my opinion.
The sunspot seen here is Sunspot 923. It currently on face-on display on the Sun’s disc and can be easily seen in a basic projected image of the Sun. It is a about 5 times the size of the Earth and is the large sunspot seen in images of the recent trasnit of Mercury.
I will be featuring many images from the Astrophotography group as I spot them and I think this is a great first.
Big doesn’t quite cover this blog post.
For the past few weeks in my role as a demonstrator in the first year undergraduates lab, I have been supervising the experiment titled Large Scale Structure of the Universe. The experiment itself is a slightly painful exercise involving a series of simulated optical telescopes on an odd piece of software installed on the lab computers. The students have to find the galaxies, which I give to them on a piece of paper, and then take a fake spectrograph reading for each one. This enables them to dot-by-dot create a small, 3D slice of the universe where they can see how far away each galaxy is from Earth and the structure the galaxies take on the largest scales.
They are, understandably, not too thrilled at this. Lab takes four hours and the preamble to this experiment takes a good hour on its own. When it is complete, and they have say, an hour remaining of lab, in which they must answer a series of questions based upon the data they have taken and the completed set of many more galaxies printed in their lab book already.
Now ignoring the fact that they seem to have taken the data for no reason at all and that this is a sure-fire way of ensuring they learn to loathe astronomy as a boring, long-winded science, what they end up with is quite interesting. Naturally none of them see it as interesting as they have been steadily bored by it for a whole afternoon, which is a great shame.
The reason it is so interesting is that on the very largest scales, the Universe has a structure. When one looks into the sky and sees the myriad of stars, nebula and galaxies one could be forgiven for thinking that the universe was pretty randomly distributed. Yet given a little thought this doesn’t seem obvious at all because eveything we have yet discovered seems to have an order.
The Earth goes around the Sun, the Sun around the centre of the galaxy. The galaxy itself is part of a larger collection of gravitationall bound galaxies called the Local Group. The Local Group is part of a larger collection known as a cluster. The clusters collect into super-clusters. There is structure at all levels. Yet at its highest order of size, the Universe still shows form and shape.
Taking every galaxy as simply a dot and then assembling all the dots together into a picture containing millions upon millions of galaxies we see the Universe looks a bit like foam. The matter (i.e. all the galaxies) mostly exisitng on the surface of bubbles, within which lies great voids of space. These regions are unimaginable large and if you were to sit at the centre of them it would be incredibly dark as there would be no stars to light things up.
There are many people studying the structure of the universe at this level. There is a survey, as a good example, called the Two degrees of freedom galaxy redshift survey, or the 2DF Survey which you can read more about at this link
What I wanted to post here though was deatils of the Millennium Simulation. In the words of the Virgo Consortium that carried out the simulation, it is
“…the largest [computer] Simulation ever carried out, containign over 10 billion particles. The simulation was carried out by the Virgo Consortium using the a cluster of 512 processors located at the Max Planck Institute for Astrophysics in Garching, Germany. The simulations took a total of 28 days (~600 hours) of wall clock time, and thus consumed around 343000 hours worth of cpu-time.”
What the simulation produced, amongst other things, was a series of movies and images from a simulated Universe. In these animations the camera flies around the universe, showing in rich detail the current best model for what the universe looks like at such large scales. It is quite beautiful to watch and I suggest you do. There are two versions of it: a 60 MB version called the Fast Flythru and then a 120 MB version which is the same journey but done more slowly so you can take more in. Both are DivX files.
A whole host of video and images are available on this website, which outlines what you’re looking at as well. You can look at the Universe as it is now or watch it evolve from its early stages to the present day.
Obviously even at 10 billion particles, the Millennium Simulation doesn’t even start to approach the actual resolution of the Universe but this is worth a look and certainly gives you an idea of exactly how teeny tiny we are here on Earth and how remarkable it is that we are able to discover such enormous ideas.
For a week now, NASA has been trying to get back in touch with the Mars Global Surveyor spacecraft that has been in space for over a decade now.
The MGS has for ten years been scouting out future landing sites for NASA whilst also returning amazing images during its systematic mapping of the Red Planet. The image included here is of the planet’s north polar ice cap, taken on October 15th this year. It is one of over 240,000 images returned by the craft during its lifetime.
Last week one of the motors on board, controlling one of the solar arrays, malfunctioned. This may have forced MGS into power-saving mode whereby it turns to allow its solar panels to face the Sun. Thomas Thorpe, MGS project manager, told the BBC that this might have brought the craft’s antennas and transmitters out of alignment with Earth.
If that is the case then no one knows where to direct the signals or if the orbiter is even recieving them. If it is, then it has been told to turn one of its low-gain anntenae toward the Earth as soon as possible and when it does communication may be re-established. So really its a waiting game.
The MGS is one of four objects orbiting Mars at present. The others are NASA’s Mars Reconnaissance Orbiter, Mars Odyssey and the European Space Agency’s Mars Express.
I have decided that instead of painstakingly creating my own page of Night Sky info each month i shall simply link to a very good one from the BBC. Its succinct, its to the point and is frankly better than mine anyway!
The link to this page can be found on the top bar of links above, along with other useful new additions in this wonderful Wordpress theme from 5thirtyone.
Skywatchers, ho! The Leonid meteor shower is now kicking off right above our heads. This often spectaculat shower results from the Earth’s passage through trails of particles left behind by comet Tempel-Tuttell. Tempel-Tuttle was itself discovered by two people independently, in 1865 and 1866.
In 1833 the Leonids were so powerful and active that some thought they were witnessing the end of the world! It appeared to rain stars in dark parts of the world (Image is a drawing from the time). As many as tens of thousands of shooting stars per hour (!) were seen in the area around the rocky Mountains in North America. This particularly strong storm was caused not by the 1833 passage of Tempel-Tuttle but by its passage in 1800. Interestingly, the men in white coats are able to determine where the path of particles lies for each of the comet’s trips around the Sun and thus tell you which comet’s tail you are witnessing as it falls into the Earth’s atmosphere.
This passage from Wikipedia detailsd some examples in a paragraph I find highly confusing: “For example spikes in activity in 2004 were associated with streams from passages of the Comet Tempel-Tuttle in 1333 and 1733 because the Earth passed through both paths, as altered by gravitational and radiative forces over the time inbetween while spikes in activity in 2001 were due in part to the passage of the comet in 1833. The 1833 storm itself was not due to the recent passage of the comet, but from a direct hit with the recent 1800 passage trail left behind and the 1966 storm was from the 1899 passage of the comet”
Hmmm. Well either way you’ll be happy to know that Jupiter is expecting to be shaking up the comet soon and this will produce much stronger meteor storms for decades to come.
The Leonids peak on November 17th so look up toward Leo in the Southern sky for what may be the best meteor shower of the year, given the Moon’s position and the dark skies.
The last time it happened was in 2003 and the next time will be 2016. The November 2006 transit of Mercury was watched by millions of people and a few spacecraft too.
Occuring between the evening of Wednesday 8th of November to the morning of Thursday 9th, GMT, Mercury appeared to move slowly across the solar disc, looking like a tiny black dot merely 1/94th the size of the Sun. On this occiasion it wasn’t visible from the UK, unlike the Venus transit two years ago.
However in the wondrous age of digital photography and the internet, this doesn’t stop us seeing some lovely pictures. A Flickr search for ‘mercury transit‘ yeiled a whole host of nice images taken by keen observers the globe over.
If you want to know more about the transit, the BBC have a very good page on the story (here) but I shall be happy here with a small collection of the best images from the web.
This is one of the best from the Flickr Collection.
I like this one showing a composite of four stages as Mercury passes across the solar disc.
This was featured on Astronomy Picture of the Day. Mercury is the little dot on the left-hand-side of the image.
To finish this animation of the 2003 Mercury transit is quite captivating as is shows the sheer scale of the Sun compared to it’s first planet. This is taken from Thierry Legault’s incredible image archive.
A couple of weeks ago I posted regarding the changing size of the Moon as seen from the Earth due to its elliptical orbit. The question was raised initially due to a conversation a friend of mine had with someone who thought that a large Moon was a harvest moon and occurred at harvest time each year.
Tomorrow will in fact be the harvest Moon for 2006. This is always the Full Moon which lies closest to the Autumnal Equinox and does indeed mark the time for harvest to be brought it. However it is not necesarily bigger or smaller than any other Full Moon through the year.
I thought though that it may be worth posting regarding something else to do with the Moon’s size and that is the ‘Moon Illusion‘ or ‘Moon Effect‘. This is the effect that we have all no doubt seen at some point, where the Moon appears huge on the horizon. You might well notic eit tomorrow if the weather is clear.
In truth the Moon is not bigger at all, and it is a common (but incorrect) belief that it looks larger due to the Earth’s atmosphere magnifying the image along the line of sight. What is really happening is far more confusing and complicated and in fact: unknown.
The odd part is that the Moon Illusion is easily proven as an optical illusion. Next time you see what you think of as a ‘large’ moon near the horizon then hold a penny out at arm’s length and compared how big the Moon looks compared to it. Then after a few hours go back outside, hold up the same penny and compare the now higher up Moon to it again. The two will remain at the same relative size - that is to say that you will realise that the Moon is no bigger or smaller than it was earlier in the night.
Yet your eyes seem to be telling you a different story. Or in fact it might just be your brain that is lying to you. Let’s take the example below. The two arcs are the same size but most people see them the top one as being shorter.
This effect is called the Ponzo Effect and is also shown is the following illustration. Only here the converging lines cause the two identical circles to appear to be of different sizes.
Some people propose that the effect of other objects in the field of vision, such as stars, trees, clouds etc are affecting the percieved size of the Moon’s disc in our mind. The idea is disputed somewhat though, since stars are often not visible around a bright Full Moon and there need not be any trees, clouds, houses or other objects present for the Moon to seem large.
A slightly better explanation may by the idea of the Sky Dome. Now I should stress at this point that this theory hasd its problems too. In fact any currently proffered explanation of the Moon Illusion has some kind of issue with it. There is no difinitive correct answer as yet. The Sky Dome is simply one example and for more you can check out this web link.
The Sky Dome model simply suggests that our mind changes the real shape of the sky since it cannot stereoscopically discern the location of objects. The sky is essentially a plane arcing over our hears and this theory proposes that our mind doesn’t quite get the arc right as it analyses the objects dranw upon it.
It is best explained by invoking the above diagram which shows the actual arc of the sky above an observer and the percieved arc created by our eyes and brain. As you can see, the angles of objects directly above our heads are projected onto a smaller area and thus appear smaller than objects at the horizon.
Don’t worry if you can’t get your head around the problem of a large Moon - humanity has been puzzling over itsince the seventh centruy BC. Ancient Greek and Chinese astronomers couldn’t fathom it, nor could Aristotle. But next time you see a big Moon at the horizon and someone tells you that its due to the atmosphere magnifying it - ignore them. Or even better: correct them…
Well today is day three (techincally) of my PhD. Monday was just an enrolment day and so yesterday was my first hands on day in the office. It is nice to be back. i’m not really wandering the same corridors as I did before and due to my two year absence I am also no recognising too many faces so in many ways it feels like I’ve started in a new place.
What is nice is that I still have the benefits of beinh ‘home’. I know where everything is and how far home and town and othe ruseful locations are situated. There at least a couple of people around that I studied with and although they are in their third and final PhD years, it has been nice to chat about the place and the dos and don’ts of life here.
As for what I’ve been doing with my time, well thats a bit odder and unfamiliar to me. I have been reducing data. Translated this means I have been turning streams of bits into images for analysis. As I understand it - and I really don’t very well at all - I have ben given the simplest kind of dataset to reduce at the moment. They are called Jiggle Maps and I am able to downbload them from the Canadian Astronomy Data Centre, which seems to house a lot of the SCUBA camera data. SCUBA, located at the James Clerk Maxwell Telescope on Mauna Kea in Hawaii, is the predecessor to the instrument I shall hopefully be using in the coming few years to observe the sky at sub-mm wavelengths. (To read more about SCUBA check out this short publication from the JCMT).
So today I made my first proper image of a sub-mm source. Taken from the SCUBA archives from 11th April 2000, I reduced this image from one set of observations that night. The object in question is located at RA 19h 03m 59.81s Dec -37d 15′ 30.7″ and is mostly like a chunk of a nebula.
Above we can see it in a simple one-colour spectrum showing intensity of the sources. Below I have put in a false-colour image of the same source which enables you to pick out a little more detail.
What you’re seeing are actually five disctinct objects. The two outer objects, that are not as bright are thought to be t-tauri stars (young, new stars) whilst the central blobs represent three, even younger objects. The left-hand central object is thought to be two protostars only slightly distinguishable here but more resolved in other data. The right-hand central object is supposed to be a pre-stellar core. That is to say that it has not yet become a star and may well in the near future.
All this data is properly collected and detailed in a paper by Nutter, Ward-Thompson and Andre that was published in 2005 title ‘The pre-stellar and protostellar population of R Coronae Australis’.
Welcome to Orbiting Frog.
I have always loved space and to look up at te night sky. I got my first telescope at around the age of twelve and ever since, I’ve been hooked. I now own a neat little Meade ETX-70 and am studying for my PhD in Astrophysics.
I’ve made many blogs in the past couple of years but this is the first one that has purpose to it, and I have been enjoying creating it and so sought a meaningful and interesting name. It had been called Spacetimes and then The Space Place, but neither worked for me.
Then I was looking up something about the first dog in space, Laika. I found some info on Wikipedia and whilst there saw a link to a page on all animals that have been sent into space.
The object that caused so much confusion in 2003 by being bigger than Pluto has now been named. The International Astronomical Union (IAU) which recently demoted Pluto from ‘planet’ to ‘dwarf planet’ after the discovery of the object (formerly known as 2003 UB313) has decided to call that object Eris, after the Greek goddess of discord. A very fitting name! A hubble image of Eris is show here.
After Mike Brown and his team discovered Eris in 2003 and announced it last year, it put Pluto’s status in jeopardy. This of course resulted in last month’s creation of the dwarf planet category. The decision had caused much controversy and chaos in the astronomy community and so the name has been chosen to reflect that.
Eris has a moon, which has been named Dysnomia. Dysnomia was the daughter of Eris and was the goddess of lawlessness (the greeks really did a god for everything it seems). Eris has a highly elongated orbit and takes 560 years to go around the Sun. It is currently at its closest approach and so its discovery is quite coincidental and could indicate that there are other large objects hiding out there beyond detection.
In my blog post on Meteorites I mentioned the Moon formation theory regarding what is known as the Giant Impact Hypothesis. This theory is widely becoming regarded as the best model science has for the Moon’s formation.
Regardless of the evidence for and against this model, here is how it works…
We set the scene around 4 and a half billion years ago, just a few tens of millions of years after the Earth’s formation. At the same time as the Earth has formed, another body, dubbed Theia, has also been created at one of the Langrangian points (proably L5) along the Earth’s orbit. Lagrangian points are those at which the gravity forces of the Sun and Earth are minimal or non-existent - The Hubble Sapce telescope sits at L2 for example.
As Theia grew, it eventually got too big for its position (around the size of Mars) and began to sway in its orbit, eventually being flung at an angle toward the Earth, attracted by its gravitational pull.
It hit the Earth, throwing of huge amounts of debris and itself being destroyed in the impact, merging eventually with the Earth and also the material flung outward.
Caught in the Earth’s gravity, the debris coalesces itself into a body - the Moon - and settles into a tidally locked orbit, meaning that the same face always presents itself to the Earth.
I went looking for an animation of these events and found one on Wikipedia:
The object was named Theia after the greek Titan who gave birth to Selene, goddess of the Moon.
The other day there was a partial Lunar eclipse (shown in this photo from NASA’s Astronomy Picture of the Day website). A friend of mine, James, noted that the Moon was really big that night too as it rose with a chunk missing in the evening. The size is exaggerated in the above image by a clever use of a zoom lens but regardless the moon was a little larger than usual.
The Moon goes through a cycle during its orbit, being at one point closest and at another, farthest. If these points occur during the Full Moon the effect is very obvious to the eye as shown in the two comparison photos below.
The Moon’s orbit is not circular in shape but rather it is elliptical (as are all orbits) and thus it cycles between being nearer to us, at what is called perigee (~348,000 km), and then farthest from us at apogee (~398,000 km). In August, this year perigee occurred just one day before full moon.
The Moon takes 27 days and 7 hours to complete a rotation around the Earth. However during that time, the Earth has moved in its own orbit around the Sun and so it takes 29 and a half days to go from Full Moon to Full Moon since the lunar phases depend on the angle between the Sun, Moon and Earth.
Therefore if apogee or perigee occur at Full Moon in any given Month they will next occur slightly earlier in the next Month and so on back through the lunar cycle. This neat animation shows both effects quite nicely in one complete lunar phase cycle.
Therefore if apogee or perigee occur at Full Moon in any given Month they will next occur slightly earlier in the next Month and so on back through the lunar cycle.
So large moons occur once a month, but the effect is most pronounce at Full Moon. They occur at a different time each month and the cycle is not annual. It takes many decades for a large, full moon to land exactly on the same day in the year.
As a side note, down the left hand side of the answer is a scale picture of the Earth Moon system. The moon here is shown midway between apogee and perigee but it does give you an idea of the sizes and angles involved.
I wasn’t really looking forward to Thursday’s ‘Extraterrestrial Sample Analysis’ talk. The title is dull because of the words sample and analysis and the extraterrestrial I felt was sure to be a false hope.
I was very wrong. It turns out that a team at the OU analyses meteorites, comet samples and even material from the Sun and Mars. I knew nothing about this topic until today’s talk which was not only extremely well-done and informative but also very cool because chunks of various objects were passed around the room.
You may remember a few years ago now when a team declared that they had found what they believed to be a fossilised bacteria on a meteorite that came from Mars. They found this meteorite in Antarctica and it had apparently fallen to the Earth 1,300 years ago. This was front-page news not too long ago and they are still unable to prove it beyond doubt. Regardless of the authenticity of the ‘lifeform’ embedded in the rock, my question was always ‘how do they know that it came from Mars?’.
I have read countless articles over the years that speak of rocks that come from space but never realised that scientists can now tell you which Solar System body they originated from! I find this quite incredible.
The science is reasonably simple once you see that every body created in the Solar System has a unique signature of Oxygen isotopes. If you don’t know what an isotope is, don’t worry. The gist is that there are several slightly different , but fairly common forms (isotopes) of the element Oxygen (with 16, 17 and 18 neutrons each). Oxygen is part of what makes rocks and most things in the Solar System are made of rocks!. So material on the Earth, formed in the exact conditions that the Earth was: i.e. the formative temperatures, pressures etc, have a particular ratio of these three types of Oxygen inside them. Martian rocks have another ratio. Every separately created body has its own magic number.
So when a rock here on Earth falls from the sky they can analyze it and keep track of where ii has come from. Over the past few decades we have been sending probes to other worlds and have analysed the Oxygen isotope ratios that have been found.
We now know that we are in possession of 40 meteorites that were once a part o the Moon. We have 31 pieces of Mars too. Several of the members of the asteroid belt are regular donators of meteorites and we have lots of chunks of Vespa and Pallas.
So the photo at the top shows an 8 kg chunk of iron that was originally a part of Vespa. It is worth around £20,000. In this picture here, a small 5g piece of Mars. It comes from the same rock that was found in Alan Hills in Antarctica, in which the bacteria was possibly found and is also worth around £20,000 - thats £4,000 per gram!
I apologise for the quality of the pictures; it was dark and I only has my cameraphone on me.
I also had explained to me during this talk something else that I had long held with suspicion. There is a theory that the Moon was formed when a giant body the size of Mars collided with the young, molten Earth. The collision threw out material which eventually formed the Moon and the Earth absorbed the colliding body, known as Theia.
This talk and the same Oxygen isotope ratios provide the reason and evidence for this theory - which is ever more generally accepted. When these ratios started to be measured, they found something startling: the rocks brought back from the Moon have exactly the same Oxygen isotope composition as Earth samples! That is to say that the Earth and Moon have to have been formed as one body and then at some point been divided. Its incredible what can be found when people look deep enough into things. Especially into rocks, it seems.
This week I am in Milton Keynes takin part in PPARC’s Summer School. PPARC is my funding body for the PhD, it stands for Particle Physics and Astronomy Research Council. They have put up around 100 of us in the Jurys Inn hotel in MK and we are attending lectures daily at the Open University, which has its headquarters in the city. The Summer School takes place annually for new PhD students and moves from university to university each time.
I have been enjoying the talks for the most part so far, several have not only innately interesting topics but also have been delivered with enthusiasm and humour. There are of course always those people than manage to produced endless black and white slides, showing dull graph after graph but on the whole so far, the former is outweighing the latter.
With six talks each day this week, the going has been a bit tough. We seem to get back to our rooms only after around 8pm which makes it a very long day. I have been relaxing late at night to the odd rhythms of BBC News 24, trying to digest the days eclectic mix of lecture topics.
So far we have been given the cutting edge brief on
Robotic Telescopes
Gamma Ray Bursts
Cosmic Microwave Background
Magnetars and Quasars
Astrophysical Jets
Galaxy Formation
Large Scale Structure of the Universe
There is plenty more still to come and I shall be outlining some of the above topics in the coming fortnight. I’m looking forward to Friday’s exoplanets talks and tomorrow’s astrochemistry. Can it be that this kind of enthusiasm and edgy research is a good taste of things to come? I hope so. This week is really getting me excited about getting back into physics again in a couple of weeks time.
As well as our own Moon passing in front of the Sun and creating an eclipse on Earth, we also can see eclipses occurring on other worlds. Jupiter’s four galilean moons are regularly seen moving in front of the planet and casting a shadow onto the gas giant’s surface. You can observe this even through a telescope in your back garden.
For the first time though, an eclipse has been seen occurring on Uranus, the seventh planet in our solar system. Hubble took this remarkable image of Uranus’ moon Ariel passing in front of the planet and casting a shadow down to the surface. Its incredible to see the detail that Hubble is able to capture as the 700-mile diameter moon moves along in its orbit.
So as well as welcoming Ceres into the new dwarf planet club with Pluto we also have to say hello to 2003 UB313, colloquially known as Xena. Xena is in fact one of the reasons that the dwarf planet category was even created since its discovery was announced in 2005 and sparked quite a storm. It is fractionally larger than Pluto and this threw into question the willingness to call Pluto a planet but not Xena. We if you read back on the blog you’ll see what’s happened since but for now lets see what else we know about one of newest Solar System members.
A team of astronomers led by Mike Brown working in California discovered Xena along with several other objects shown in the image above (Quaoar, Sedna, 2005 FY9 and 2003 EL61) whilst searching for large outer solar system objects. They used a computer to analyse data taken of the stars which could detect objects that had moved. Originally they had been careful to look for objects that were moving quite quickly and Xena was missed entirely. But after discovering Sedna, which moved slower than anticipated, they went back and did a more detailed search only to find Xena there amongst the stationary stars.
The movie above shows three frames that illustrate nicely the movement that objects like Xena make across the sky giving themselves away at more than just stars. The three frames above were taken over the course of three hours. Can you spot Xena moving along in the top left quadrant of the image?
Xena is something like 2500 km across and orbits the Sun in a highly eccentric (tilted) 557 year orbit as shown in the related diagram. It is currently at its most distant point from the Sun and so is currently around 96 times further from us than the Sun is. Xena was later discovered to have its own Moon, currently nicknamed Gabrielle. Gabrielle is much smaller than Xena as far anyone can tell. The two are shown together in this optical image taken using the Keck Telescope in Hawaii.
Xena leads a group of large, outer solar system objects occupying the Kuiper belt in the far reaches of the Solar System. They are shown in the graphic at the start of this blog post and will no doubt be studied by many people in the coming decades. Some of them maybe yet join the ranks of the other dwarf planets if they are found to be spherical in shape.
As our ground-based telescopes become bigger, better and much more accurate in the coming ten to fifteen years, we may even get some amazing pictures of these bodies that lie so far away from the Earth.
So rather than continually harp on about Pluto and how is has annoyed me that they ‘demoted it’, I thought it might be advisable to focus on one of the god things that has come out of the IAU’s recent meeting. Ceres, the largest member of the asteroid belt, has been promoted to the status of dwarf planet.
Ceres satisfies the three defining factors of that category which are that is orbits the sun and isn’t a star, that its own gravity has forced it into a roughly spherical shape and that it hasn’t cleared the area around its orbit (i.e. there are lots of other bodies in the same region as Ceres: the other asteroids). Above is the best image that has been taken of Ceres. It comes from the Hubble Space Telescope.
Ceres accounts for one third of al the mass in the asteroid belt and orbits between Mars and Jupiter with a period of about 4.6 years. Ceres was discovered on January 1st 1801 by the Italian Giuseppe Piazzi by accident (he was looking for something else altogether). Its official name is 1 Ceres because it was the first object of its kind to be discovered, the next objects being the asteroids 2 Palla, 3 Juno and 4 Vesta. However only a month after its discovery, Ceres moved behind the Sun, from Earth’s perspective and the astronomers effectively lost it. Only three observations had been made and they were unable to predict where it would now be.
It took the mathematician Carl Friedrich Gauss several months to develop a method whereby an orbit could be determined from just three observations and on December 31st of 1801, exactly a year after its initial discovery, Ceres was rediscovered and located once again.
At that time no asteroid belt as we know it was even thought to exist and Ceres was thusly labeled a planet. But, as would be the case with Pluto 130 years later, Ceres just wasn’t enough like a planet for most people’s liking. It was too small and so William Herschel (the man who discovered Uranus amongst other things) coined the term asteroid, meaning star-like. It wasn’t long before more objects were discovered in the same region and 50 years later Ceres was no longer a planet but simple the largest member of the asteroid belt. It held that status until last week when it became a dwarf planet along with Pluto and 2003 UB313.
Ceres remains very much a mystery even today. The first mission to actually study it up close is NASA’s Dawn project and that will arrive at Ceres 2014 or 2015. It was a mysterious white spot on its surface, which no one has identified formally. In 1995 someone spotted a dark object, thought to be a crater, and named it Piazzi after Ceres’ discoverer but Piazzi was no longer detectable next time anyone looked!
I have included an image here from Wikipedia’s Ceres article showing the size of the first ten asteroids laid over our Moon. It shows very well how small Ceres really is at a diameter of 950 km. Ceres is now the closest Dwarf planet to the Earth at at time of writing was only twice as far from our us the Sun. However it is not generally visible to the naked eye. I welcome Ceres to the new club of dwarf planets and wish it well in future endeavours.
