BBC The Sky at Night (1957) s23e09 Episode Script
Galaxy Zoo
Good evening.
We know that our sun is one of 100 thousand million stars in our galaxy.
But our galaxy is not the only one.
There are untold millions of others and they're of different shapes.
Some are spirals, like Catherine wheels.
Some are elongated, some are spherical, some are totally irregular.
And astronomers are very keen to know how many galaxies there are of each type.
But, of course, there are so many galaxies that one team can't possibly do it.
Therefore, why not bring in the amateurs? After all, astronomy is still about the only science where amateurs can, and do, play a very useful part.
And Chris Lintott came up with what he calls Galaxy Zoo.
With us, Dr Kate Land and Professor Bob Nicoll.
Well, Chris, you started all this.
What exactly is Galaxy Zoo? It was a simple solution to the difficult problem that we've got too much data to play with.
In the old days, astronomers thought themselves lucky if they looked at 30 galaxies in their career, and you made it very detailed study of those 30 galaxies.
You hoped to learn something about the universe.
These days, as you said in your introduction, we have literally hundreds of thousands of the things.
No astronomer could sort through them all.
So we need to find new ways of looking at our data.
The problem is, that we still want to care about each and every galaxy individually.
They've all got their own stories and they've all been seen by modern surveys, particularly the Sloan Digital Sky Survey which Bob helped produce.
What exactly is the Sloan? The Sloan Digital Sky Survey was the first digital map of the northern sky.
About the mid-80s, we were starting to get these little CCD cameras, which now every amateur has a CCD camera.
Everyone has, it's in a digital camera.
It's your mobile phone.
But in the mid-'80s these were new technology.
People started to put them at the back of telescopes and take photographs with these digital cameras.
They thought, "If we mosaic a bunch of these CCDs together, "we could have a very big camera "and we could potentially digitise the whole northern sky.
" I'm proud to say that, 20 years later, we've done that.
There is now a digital map of the whole northern sky.
How many galaxies, roughly? Well, there's about 200 million objects in the catalogue, of which half of those are galaxies.
About 100 million galaxies.
Impressive number.
Yes, that's a lot.
Also, in these pictures you can see the shapes.
Absolutely.
So, for this brightest million, which we now have distances for, the resolution of the telescope is good enough to see the shape.
There's a tremendous amount of information in the pictures.
That's one thing that this automated Sloan couldn't do.
It could not take those pictures and say, "There's a disc, there's a bulge.
" It's something a computer can't do right now.
What about spinning galaxies, clockwise or anti-clockwise? Well, we know you get a bit of both.
Spiral galaxies are rotating.
We can tell that by the arms.
You've got these nice swirling arms, which trail in the direction of the rotation.
If the spiral's clockwise, it's turning anti-clockwise.
So we can look at the arms and tell which way the galaxies are rotating.
And you get a lot rotating clockwise and a lot rotating anti-clockwise.
It depends which side of the galaxy you're sitting on.
So it's not an inherent property of the galaxy, it's just the way we observe it.
Chris, you still haven't said exactly what Galaxy Zoo is.
That's right.
We were talking about the problem.
Understanding the shapes of these galaxies is important.
It's the key to unlocking their history and how they came to be where they are now.
Bob said that computers aren't that good at doing this.
They get most right, but they miss the weird and wonderful, the unusual ones that tell you about what's really going on.
There are plenty of those.
The only way to do that is to look.
Amateurs have always done astronomy.
They've discovered comets, supernovae, monitored the planets, explored the sky But you've needed a telescope and a dark site to do that.
What we did was took the Sloan images, which the collaboration had made available to anyone, and we created a website, galaxyzoo.
org, which showed people these images, taught them what we were looking for.
We were just asking some questions, is it a spiral galaxy, with spiral arms and a disc, or is it elliptical, a big ball of stars? How many people took part in your little survey? Many more than we thought would.
Within 24 hours of launching, we were doing 70,000 classifications an hour.
I found that you can do your classification of each galaxy in about a minute, something like that.
I think it depends on how carefully you Some people, I think, only spend a few seconds on an image.
I find I have to spend a minute at least.
You're thinking like an astronomer.
you're too professional! You were trying to work out This is why We found when we look at a galaxy We should try this, let's have a look.
I happen to have my laptop here.
It happens to be open to Galaxy Zoo.
Here we go.
Four classifiers here.
What do you reckon? Well, it's edge on.
It's quite a bulge, isn't it? It could be a spiral galaxy we are seeing looking along the edge of the disc.
Exactly.
But you're right.
There is a dust lane that you can see.
You're right.
We are picking over this one too much.
What we need people to do, initially, is just pattern recognition.
Actually, one interesting thing about this, Chris, is that your brain, this is again why the brain is so much better than the computer, a computer would find it difficult.
Edge-on things, for a computer, are incredibly difficult.
Your brain immediately picks up the orientation here.
Well let's classify this one.
If I click, that will be added to the database.
Here's the next one.
Ah, that's just an elliptical.
OK? Definitely an elliptical.
Patrick? Yes.
We don't show people the distance information.
I'm not quite sure about that one.
There's no sign of any spiral features.
I'll classify it.
We're taking less than a minute.
Even the automated algorithms that try and do this typically take five minutes to give you an answer per galaxy.
Even if you wanted to do it via a machine, it might actually take you many, many months to try and do the automated algorithm on these.
Whereas humans do it quicker.
Even if you preferred to do it through a computer, it would have taken longer to do it.
We've had the world's biggest computer work for us.
It's just been everybody's brain.
We're seeing spirals, ellipticals, edge-on galaxies, but there are other things too.
Some rather weird things.
Some wonderfully weird things.
It's not something we thought of when we launched this.
Kate or Bob, I don't know if you knew this would be a side-effect.
Every time you look in a haystack, you find a couple of needles.
And people told us about the needles through the Galaxy Zoo forum, which is a discussion board that we set up.
They talk to each other about the weird things they find.
Sometimes they're just fun.
There's the Penguin Galaxy, for example, which is rather good.
There's lots that look like flowers.
There's a thread of galaxy images that look like roses.
Or the alphabet.
So we can write The Sky At Night in galaxies! That's fun, but then there's serious science.
The classic example is an object we've come to call the Voorwerp.
You showed that to me and I saw it there.
What it was, I just didn't know.
No, it was a Dutch schoolteacher, Hanny van Arkel, who found this.
She said, "What's this?" A bunch of astronomers, us, the team behind the site, said, "Well, we don't know.
" We thought about it for a bit.
Eventually, we used a telescope in the Canary Islands, the William Herschel telescope.
We got a spectrum of it.
We found that this object, it's about galaxy-sized, it's a small galaxy.
The size of a dwarf galaxy.
But it's only gas.
It doesn't seem to have any stars in it.
How far away? About 600 million light years.
Nothing spectacular by astronomical standards.
It's got no stars in it but it's very hot.
The gas is at least 10,000 Kelvin.
So the question is, how did the gas get to be so hot if there aren't any stars there to heat it? Well, the discoverer, Hanny van Arkel, actually came here to talk to me about it.
I actually had to classify the galaxy next to it, next to the strange thing I found.
So I quickly classified that and then I thought, "Wait, what was that?" And I clicked the back button and I saw this strange blue sort of cloud.
It caught my eye because it was very blue and it had a strange form.
It was nothing like the irregular galaxies I had seen.
But I didn't think it was very special either.
But I was just wondering what it was.
Well, very sensibly, you notified others.
What did they say? Yes, I posted it on the Galaxy Zoo forum and I mailed the Zookeepers, the team.
All of them were just saying it was weird and looked interesting.
And nobody really had an answer.
Hanny, thank you for joining us.
Thank you.
Well, this thing we have called the Voorwerp, what's your idea? What is it? Well, we think of it as a crime scene, I think.
Something has heated the gas and there's no obvious culprit.
Here's the best answer we've come up with.
We're still trying to get this published, so who knows whether anyone comes up with a better idea! Next to the Voorwerp, which, by the way, is Dutch for object.
Next to the Voorwerp is another galaxy, IC2497, which looks like a perfectly normal dusty spiral.
Most big galaxies have black holes at their centre.
Our Milky Way does, Andromeda does.
So do many, almost all of the big spirals.
So there must be one in the middle of IC2497.
If a short time ago lots of material was falling on to the black hole, that galaxy could be what we call an active galaxy.
It could have a luminous core, if you look in x-rays.
It would have jets coming out from the centre.
We think the Voorwerp just happened to get in the way of one of these jets.
But, the black hole has since turned off.
So we still see the effects, we see the Voorwerp being heated, but we no longer see the culprit.
The black hole is lying low at the centre of the galaxy.
What was the Voorwerp and how do it get there? It may have just been a passing, small, unprocessed dwarf galaxy making its first approach to a big system, I guess.
Well, Chris, that's the Voorwerp.
What is happening about it now? We're waiting for next month, when the astronauts go up to the Hubble space telescope and repair it.
Then one of the first objects in the queue will be the Voorwerp.
We've got approval for seven orbits of Hubble time, that's how we measure these things, to look at this object.
I'm really excited.
It's the first time I've succeeded in using Hubble! So that will be great.
We also want to look in the radio and infra-red to see if there's a black hole hidden at the centre of the neighbouring galaxy that is active, but just hidden.
Now you've been surveying for some time, what do you think are the most important results from Galaxy Zoo so far? There's been this extremely long-standing problem in extra-galactic astronomy.
That is, as you pointed out at the beginning, there seems to be two types of galaxy.
There's the elliptical and there's the spiral.
And we've known that ellipticals like to live together.
They like to live in clusters of galaxies which we call star cities.
The spirals tend to like to live in the outskirts, maybe in the suburbs of these big galaxy cities.
But no one's put their finger on why, what is actually going on, why do all the ellipticals live together? Why do the spirals live on the outskirts? There's clearly some environmental dependence going on here.
But no-one's really worked out what it is.
So when Chris mentioned it to me, I suddenly saw the opportunity to look at it in much, much greater detail.
As Chris alluded to, as professionals, we've been unable to build the big samples.
We've been unable to get lots of galaxies where we know there's a spiral, we know it's an elliptical.
But what had been used in the last 10 years by a lot of my Sloan colleagues, instead of using the shape, because they didn't have the shape, they had used another surrogate called colour so they could look at the object.
Instead of calling it an elliptical, they used to call it a red galaxy.
Instead of calling it a spiral, they'd call it a blue galaxy.
In fact, people were quite sloppy.
What they would do, when they meant spiral, they would say blue galaxies and when they meant ellipticals, they would call them red.
Most spirals are blue because they've got star formation.
Most ellipticals are red, because they don't.
But what's emerged are two new types of galaxy that we didn't predict, I think.
That is we are finding blue ellipticals, so they have the shape of a elliptical galaxy but their colours are bluer than their colleagues.
We're finding red spirals.
We are finding things that certainly have spiral arms, so they've got old stars in.
So that's a great result.
We were jumping up and down when we discovered that.
We've actually discovered 10,000 of these red spirals.
And many more blue ellipticals as well.
Many more.
But the absolutely fascinating thing we discovered is that, as you went into these clusters, the number of red spirals, so the number of these things which have spiral arms but don't have the colours of other spirals, the number of those increase.
What you can say definitively is these red spirals live in clusters.
They don't live on the outskirts, they are mostly in the clusters.
That really is pointing to an environmental effect, where the spiral's blue on the outskirts, and as it comes into the cluster what we think is happening, and this comes back a little bit to the Voorwerp object that we talked about earlier, is that around the spiral can be a cocoon of gas.
And you're not seeing it.
But that cocoon of gas is feeding the star formation.
So, as the spiral comes into the cluster, that cocoon of gas is blown off by a wind.
And so what's happening is there's no cocoon of gas left over.
So no fuel.
No fuel.
And so what we like to use in astronomy, we use wonderful phrases, like we believe that galaxy has been either "starved" of its gas or it's "strangled", OK? So what happens is that the star formation shuts down and that spiral becomes red.
And then maybe the final part of the story for our poor spiral heading into the big city for the first time is that we know that one way to produce ellipticals is to crash two spirals together.
We see examples of this happening in galaxies.
We have a huge sample of merging galaxies.
Antennae.
The Antennae or the Mice are things that are probably on their way to forming ellipticals.
So maybe after they've gone into the big city and been strangled, mugged We should be mugging the galaxies! Then they'll bash into one of their colleagues and end up as a nice elliptical sitting exactly where we want ellipticals to be.
I got hooked and I began doing it in a very mild way, as you know.
You say you're calling for volunteers now.
Suppose there's someone watching us at the present moment and they'd like to join in.
What do they do? They go to our website, which is galaxyzoo.
org, where very, very shortly a whole new task will be set for our army of volunteers.
Oh, dear! What's this one? We realised a couple of things.
One is that by comparing to professional classifications, our volunteers are really good at this.
We saw that when we tried to classify galaxies.
It's much better to get the public to do it.
Astronomers have learnt to ask more complicated questions.
How tightly wound are the spiral arms? Actually, how many spiral arms are there? And how big is this bulge at the centre? Is there a bar at the centre, or do the spiral arms go all the way into the centre? That's a debate that's been happening for our Milky Way for years.
Yes.
We're going to take the quarter of a million brightest - and therefore prettiest, by the way - galaxies in the Sloan, and we're going to ask people to give us detailed classifications of those, not by learning classifications but by answering a series of questions.
And then the other thing we realised is that we CAN find these unusual objects.
We talked about the Voorwerp.
There are all sorts of examples.
We're going to make it easier for people to tell us when they find something unusual.
The feedback we've had on the forum from e-mails has been incredibly positive, and it's been very nice to hear that people really do enjoy astronomy.
A lot of people think the public aren't interested.
But I think we've proved them wrong by the amazing success of Galaxy Zoo.
And there's something that they can really do and be useful at the same time.
I had a go at it.
I've been observing the moon.
I don't know anything about galaxies at all! But I've thoroughly enjoyed doing it.
And you'll get to carry on, then.
Absolutely, and we've got plans in place for at least the next three years.
And we've got plenty of work for 160,000 people and many more.
Come back before very long and tell us what the latest results are.
And congratulations to you, Chris, for starting it and to you for carrying it on.
So it's a great business.
Well now, we've been talking about galaxies.
You can see some with small telescopes or even binoculars, and outside my observatory, Pete Lawrence is there to have a look at some of them.
As we head in to September, there are some fantastic galaxies on view, and we have the virtue of having one of the brightest in the entire night sky, M31, the Andromeda galaxy, a beautiful spiral galaxy in the constellation of Andromeda.
Now, we can find M31 quite easily.
We can use an old friend, which is the Great Square of Pegasus.
At this time of year, the Great Square of Pegasus is rising in the hours before midnight in the east, so it's fairly easy to find.
If we can locate the Great Square, locate the two stars at the top of the square and extend them to the left by about the same distance as the square side.
Go up slightly from that point and you'll come to another star, which is about the same brightness as the stars in the Great Square, and this is Beta Andromedae, and it's a key star for finding the galaxies which I shall be talking about in a moment.
Now, if you turn ninety degrees going up from Beta Andromedae, you'll come to fainter star, which is known as Mu Andromedae.
Keep going up again and you'll come to another star, which is even fainter still, which is Nu Andromedae.
And if you can find Nu Andromedae, the galaxy M31 is just above that.
To the naked eye, in dark skies it looks very obvious.
It's an elongated smudge of light.
In fact, it's a bit of a tease, but I'll come back to why in just a moment.
If you've got a pair of binoculars or a telescope using a low power, if you look at M31 you actually get three galaxies for the price of one, because very close to the core of M31 there are two elliptical galaxies, which are actually satellites of M31 itself, they're actually in orbit around the core of M31.
Now, these two elliptical galaxies actually look slightly different to one another.
If you can locate the one which is due south - it's about a third of a degree due south of the centre of M31- that's known as M32.
It's quite bright, and if you look at it with a telescope, you start increasing the power, you'll see that it looks just like a ball of stars.
It looks like a fuzzy star, actually.
The other one is NGC205, and to find NGC205 you have to go from M32, through the centre of the core and up and slightly to the right.
A little bit further out this time, about half a degree.
Again an elliptical galaxy, but this time it's actually slightly elongated.
But M31 is a spiral galaxy.
If you look at it with a pair of binoculars or a telescope using a low power, what you're most likely to see is just a larger version of what you can see with the naked eye.
And there's a good reason for this, because the fuzzy patch you see with the naked eye is actually just the core of M31.
The spiral arms are there - they extend out much further - but you can't actually see them.
They're too dim.
And there's another problem with M31, in that it's actually tilted over to us by quite a large angle, about 77 degrees, and that means we see it quite obliquely on.
So even if we could see the spiral arms, it would be difficult to see much structure.
To see a spiral galaxy in its full glory, we need to find one which is more or less face-on to us.
And fortunately, there is one very close by.
In fact, if we go back to M31, join a line from M31 to Beta Andromedae - this is the star we found earlier - and then extend it for the same distance again, going downwards this time, the end point of that line marks the position of another famous spiral galaxy, M33 in the constellation of Triangulum, the Triangle.
In fact, it's known as the Triangulum Galaxy.
Now, this is a wonderful object.
But if you look at it with a telescope using a reasonable magnification, you probably won't see anything at all.
It's large and it has a low surface brightness.
What happens is you're looking right through the galaxy.
What you need to do to see it is to use a low power, and a pair of binoculars is ideal or a low-power eyepiece.
If you do this, you'll be able to see that it has an elongated, smudgy appearance.
But if you keep staring at it, you may be able to see the structure start to form in those spiral arms.
You may be able to pick it out.
It looks like some sort of fantastic celestial Catherine Wheel, if you like.
Now, M33, M31 and its two companion elliptical galaxies are going to be up for several months yet, so if you have a telescope, a pair of binoculars or even just your eyes, go outside and look at these fantastic objects.
They're just wonderful.
Well, that's good advice.
Now, back indoors, and we're joined by Martin Mobberley.
Now, on August 1st we had an eclipse of the sun.
It was only a small partial eclipse here.
I did take a picture of it, but not very spectacular.
But Martin was in the tack of totality, so, Martin, can you tell us where you were and what you saw? Well, Patrick, I'm sure you'll agree that total solar eclipses are just about the most awesome spectacle that you can possibly see.
For this particular eclipse, I was in a place called Novosibirsk, which is Russia's third-largest city, not far from the Russia-Chinese border, and we had a spectacular two minutes nineteen seconds of totality.
I am green with envy! Well, the trouble with all these eclipses is they're spectacular, they're awesome, but the time just flies by.
The two minutes nineteen seconds just seems like about 30 seconds, and you wonder where the time went.
But the most dramatic pictures I've seen of this eclipse were by the master, the undisputed master of coronal imaging, Miroslav Druckmuller, who's from the University of Technology in Brno.
This is incredible, this picture.
And his pictures are just awesome.
He takes about 20 pictures of various exposures, combines them, flat-fields them, dark-frames them, aligns them and spends weeks processing the images.
And this is the sort of spectacular result he gets.
Well, I envy you.
And luckily, there's another eclipse next year, another totality.
You will see it, so will you, Chris.
Very sadly, I shan't.
Thank you, Martin.
Thank you.
On other news next Phoenix on Mars has been doing great things.
Yes, we're just at the end of the third month of its time on Mars, and it's been working very hard indeed, firstly to get samples from the soil into its ovens, an instrument called Tiga, which can then heat them and we can look at the chemical composition of the Martian soil.
Phoenix has got three very important samples already into its ovens.
It's had one from the surface, one from the ice layer they discovered just five centimetres underneath that surface and now in the last month one from just in-between.
So we have a good sense of how the properties of the Martian soil change in this exotic location.
Phoenix also has a microscope, half of the Mecca package.
They've been taking a close look at the soil and also using something called an atomic force microscope to get very detailed images of individual Martian dust grains.
So, observers have always seen dust on Mars - you see dust storms, we've seen dust devils from the rovers.
Well, now we can see the dust grains themselves, and that's a fantastic result.
They've been looking at the chemistry of the soil, too.
Yes.
The results are confusing.
We've known for the last couple of months that the soil is alkaline, but the chemistry is more complicated than that.
We've been told that there are chemicals called perchlorates there.
It doesn't matter what a perchlorate is.
But it's a complicated chemistry, so it's going to take some time to understand those results.
And time is something that Phoenix doesn't have.
No! It's been in the Martian arctic, so it's had midnight sun until now, but just a week ago there was the first sunset as seen from Phoenix.
There's an amazing image of it.
But that mean that Phoenix, which depends on solar power, is going to be able to do less and less.
They've got about a month of good, hard-working robotic arm time left.
So the team will want to make the best use of that time, because they're seeing frost forming on the surface overnight already.
Eventually, that frost will cover the lander and Phoenix won't survive the Martian winter.
No.
I fear Phoenix cannot survive through the Martian nights.
Let's go out now to the further reaches of our own solar system, to Saturn and that weird moon Enceladus.
And the Cassini probe made another close fly-by, and it has become more and more amazing.
The tiger stripes near the pole, they're where the fountains come out.
That's right, and these seem to be the source of Enceladus's most intriguing feature.
These are the Fountains of Enceladus, which shoot out from one end of this small moon that has no right to have any activity on it whatsoever.
Cassini flew close to the surface, just a few tens of kilometres, and they had to invent a whole new mode of imaging to be able to capture these spectacular images.
What you're seeing here is a series of V-shaped fissures - valleys, I suppose, if you like - about three hundred metres deep, and it's from these that these eruptions are happening.
The sides of the valleys are covered in some sort of fine material.
We're not sure what that is yet.
There are these blocks of ice the size of houses surrounding either side of the fissures.
So what all of this means I've no idea, but this is the key to Enceladus's mystery.
Well, in my view, the Fountains of Enceladus are the most mysterious things we've found yet.
And one more thing - Fermi.
Yes, a new space telescope which used to be known as GLAST.
It was launched a few months ago, and looks at the high-energy part of the sky.
So it's been named after Enrico Fermi, the great pioneer of high-energy physics.
And we have the first map from it.
The stripe you can see is the Milky Way, and then there are three or four other objects.
Three of those are pulsars and one is a strange active galaxy called a blazar.
And Fermi's mission will be to look at these active objects and try and understand them and to catch the biggest bang since the beginning of the universe, gamma-ray bursts.
Well, it certainly has much to tell us.
And of course, we'll keep everyone up to date.
Chris, Martin, thank you very much.
When I come back next month, we'll talk about the autumn sky and join in an autumnal equinox star party.
Until then, good night.
E- mail subtitling@bbc.
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We know that our sun is one of 100 thousand million stars in our galaxy.
But our galaxy is not the only one.
There are untold millions of others and they're of different shapes.
Some are spirals, like Catherine wheels.
Some are elongated, some are spherical, some are totally irregular.
And astronomers are very keen to know how many galaxies there are of each type.
But, of course, there are so many galaxies that one team can't possibly do it.
Therefore, why not bring in the amateurs? After all, astronomy is still about the only science where amateurs can, and do, play a very useful part.
And Chris Lintott came up with what he calls Galaxy Zoo.
With us, Dr Kate Land and Professor Bob Nicoll.
Well, Chris, you started all this.
What exactly is Galaxy Zoo? It was a simple solution to the difficult problem that we've got too much data to play with.
In the old days, astronomers thought themselves lucky if they looked at 30 galaxies in their career, and you made it very detailed study of those 30 galaxies.
You hoped to learn something about the universe.
These days, as you said in your introduction, we have literally hundreds of thousands of the things.
No astronomer could sort through them all.
So we need to find new ways of looking at our data.
The problem is, that we still want to care about each and every galaxy individually.
They've all got their own stories and they've all been seen by modern surveys, particularly the Sloan Digital Sky Survey which Bob helped produce.
What exactly is the Sloan? The Sloan Digital Sky Survey was the first digital map of the northern sky.
About the mid-80s, we were starting to get these little CCD cameras, which now every amateur has a CCD camera.
Everyone has, it's in a digital camera.
It's your mobile phone.
But in the mid-'80s these were new technology.
People started to put them at the back of telescopes and take photographs with these digital cameras.
They thought, "If we mosaic a bunch of these CCDs together, "we could have a very big camera "and we could potentially digitise the whole northern sky.
" I'm proud to say that, 20 years later, we've done that.
There is now a digital map of the whole northern sky.
How many galaxies, roughly? Well, there's about 200 million objects in the catalogue, of which half of those are galaxies.
About 100 million galaxies.
Impressive number.
Yes, that's a lot.
Also, in these pictures you can see the shapes.
Absolutely.
So, for this brightest million, which we now have distances for, the resolution of the telescope is good enough to see the shape.
There's a tremendous amount of information in the pictures.
That's one thing that this automated Sloan couldn't do.
It could not take those pictures and say, "There's a disc, there's a bulge.
" It's something a computer can't do right now.
What about spinning galaxies, clockwise or anti-clockwise? Well, we know you get a bit of both.
Spiral galaxies are rotating.
We can tell that by the arms.
You've got these nice swirling arms, which trail in the direction of the rotation.
If the spiral's clockwise, it's turning anti-clockwise.
So we can look at the arms and tell which way the galaxies are rotating.
And you get a lot rotating clockwise and a lot rotating anti-clockwise.
It depends which side of the galaxy you're sitting on.
So it's not an inherent property of the galaxy, it's just the way we observe it.
Chris, you still haven't said exactly what Galaxy Zoo is.
That's right.
We were talking about the problem.
Understanding the shapes of these galaxies is important.
It's the key to unlocking their history and how they came to be where they are now.
Bob said that computers aren't that good at doing this.
They get most right, but they miss the weird and wonderful, the unusual ones that tell you about what's really going on.
There are plenty of those.
The only way to do that is to look.
Amateurs have always done astronomy.
They've discovered comets, supernovae, monitored the planets, explored the sky But you've needed a telescope and a dark site to do that.
What we did was took the Sloan images, which the collaboration had made available to anyone, and we created a website, galaxyzoo.
org, which showed people these images, taught them what we were looking for.
We were just asking some questions, is it a spiral galaxy, with spiral arms and a disc, or is it elliptical, a big ball of stars? How many people took part in your little survey? Many more than we thought would.
Within 24 hours of launching, we were doing 70,000 classifications an hour.
I found that you can do your classification of each galaxy in about a minute, something like that.
I think it depends on how carefully you Some people, I think, only spend a few seconds on an image.
I find I have to spend a minute at least.
You're thinking like an astronomer.
you're too professional! You were trying to work out This is why We found when we look at a galaxy We should try this, let's have a look.
I happen to have my laptop here.
It happens to be open to Galaxy Zoo.
Here we go.
Four classifiers here.
What do you reckon? Well, it's edge on.
It's quite a bulge, isn't it? It could be a spiral galaxy we are seeing looking along the edge of the disc.
Exactly.
But you're right.
There is a dust lane that you can see.
You're right.
We are picking over this one too much.
What we need people to do, initially, is just pattern recognition.
Actually, one interesting thing about this, Chris, is that your brain, this is again why the brain is so much better than the computer, a computer would find it difficult.
Edge-on things, for a computer, are incredibly difficult.
Your brain immediately picks up the orientation here.
Well let's classify this one.
If I click, that will be added to the database.
Here's the next one.
Ah, that's just an elliptical.
OK? Definitely an elliptical.
Patrick? Yes.
We don't show people the distance information.
I'm not quite sure about that one.
There's no sign of any spiral features.
I'll classify it.
We're taking less than a minute.
Even the automated algorithms that try and do this typically take five minutes to give you an answer per galaxy.
Even if you wanted to do it via a machine, it might actually take you many, many months to try and do the automated algorithm on these.
Whereas humans do it quicker.
Even if you preferred to do it through a computer, it would have taken longer to do it.
We've had the world's biggest computer work for us.
It's just been everybody's brain.
We're seeing spirals, ellipticals, edge-on galaxies, but there are other things too.
Some rather weird things.
Some wonderfully weird things.
It's not something we thought of when we launched this.
Kate or Bob, I don't know if you knew this would be a side-effect.
Every time you look in a haystack, you find a couple of needles.
And people told us about the needles through the Galaxy Zoo forum, which is a discussion board that we set up.
They talk to each other about the weird things they find.
Sometimes they're just fun.
There's the Penguin Galaxy, for example, which is rather good.
There's lots that look like flowers.
There's a thread of galaxy images that look like roses.
Or the alphabet.
So we can write The Sky At Night in galaxies! That's fun, but then there's serious science.
The classic example is an object we've come to call the Voorwerp.
You showed that to me and I saw it there.
What it was, I just didn't know.
No, it was a Dutch schoolteacher, Hanny van Arkel, who found this.
She said, "What's this?" A bunch of astronomers, us, the team behind the site, said, "Well, we don't know.
" We thought about it for a bit.
Eventually, we used a telescope in the Canary Islands, the William Herschel telescope.
We got a spectrum of it.
We found that this object, it's about galaxy-sized, it's a small galaxy.
The size of a dwarf galaxy.
But it's only gas.
It doesn't seem to have any stars in it.
How far away? About 600 million light years.
Nothing spectacular by astronomical standards.
It's got no stars in it but it's very hot.
The gas is at least 10,000 Kelvin.
So the question is, how did the gas get to be so hot if there aren't any stars there to heat it? Well, the discoverer, Hanny van Arkel, actually came here to talk to me about it.
I actually had to classify the galaxy next to it, next to the strange thing I found.
So I quickly classified that and then I thought, "Wait, what was that?" And I clicked the back button and I saw this strange blue sort of cloud.
It caught my eye because it was very blue and it had a strange form.
It was nothing like the irregular galaxies I had seen.
But I didn't think it was very special either.
But I was just wondering what it was.
Well, very sensibly, you notified others.
What did they say? Yes, I posted it on the Galaxy Zoo forum and I mailed the Zookeepers, the team.
All of them were just saying it was weird and looked interesting.
And nobody really had an answer.
Hanny, thank you for joining us.
Thank you.
Well, this thing we have called the Voorwerp, what's your idea? What is it? Well, we think of it as a crime scene, I think.
Something has heated the gas and there's no obvious culprit.
Here's the best answer we've come up with.
We're still trying to get this published, so who knows whether anyone comes up with a better idea! Next to the Voorwerp, which, by the way, is Dutch for object.
Next to the Voorwerp is another galaxy, IC2497, which looks like a perfectly normal dusty spiral.
Most big galaxies have black holes at their centre.
Our Milky Way does, Andromeda does.
So do many, almost all of the big spirals.
So there must be one in the middle of IC2497.
If a short time ago lots of material was falling on to the black hole, that galaxy could be what we call an active galaxy.
It could have a luminous core, if you look in x-rays.
It would have jets coming out from the centre.
We think the Voorwerp just happened to get in the way of one of these jets.
But, the black hole has since turned off.
So we still see the effects, we see the Voorwerp being heated, but we no longer see the culprit.
The black hole is lying low at the centre of the galaxy.
What was the Voorwerp and how do it get there? It may have just been a passing, small, unprocessed dwarf galaxy making its first approach to a big system, I guess.
Well, Chris, that's the Voorwerp.
What is happening about it now? We're waiting for next month, when the astronauts go up to the Hubble space telescope and repair it.
Then one of the first objects in the queue will be the Voorwerp.
We've got approval for seven orbits of Hubble time, that's how we measure these things, to look at this object.
I'm really excited.
It's the first time I've succeeded in using Hubble! So that will be great.
We also want to look in the radio and infra-red to see if there's a black hole hidden at the centre of the neighbouring galaxy that is active, but just hidden.
Now you've been surveying for some time, what do you think are the most important results from Galaxy Zoo so far? There's been this extremely long-standing problem in extra-galactic astronomy.
That is, as you pointed out at the beginning, there seems to be two types of galaxy.
There's the elliptical and there's the spiral.
And we've known that ellipticals like to live together.
They like to live in clusters of galaxies which we call star cities.
The spirals tend to like to live in the outskirts, maybe in the suburbs of these big galaxy cities.
But no one's put their finger on why, what is actually going on, why do all the ellipticals live together? Why do the spirals live on the outskirts? There's clearly some environmental dependence going on here.
But no-one's really worked out what it is.
So when Chris mentioned it to me, I suddenly saw the opportunity to look at it in much, much greater detail.
As Chris alluded to, as professionals, we've been unable to build the big samples.
We've been unable to get lots of galaxies where we know there's a spiral, we know it's an elliptical.
But what had been used in the last 10 years by a lot of my Sloan colleagues, instead of using the shape, because they didn't have the shape, they had used another surrogate called colour so they could look at the object.
Instead of calling it an elliptical, they used to call it a red galaxy.
Instead of calling it a spiral, they'd call it a blue galaxy.
In fact, people were quite sloppy.
What they would do, when they meant spiral, they would say blue galaxies and when they meant ellipticals, they would call them red.
Most spirals are blue because they've got star formation.
Most ellipticals are red, because they don't.
But what's emerged are two new types of galaxy that we didn't predict, I think.
That is we are finding blue ellipticals, so they have the shape of a elliptical galaxy but their colours are bluer than their colleagues.
We're finding red spirals.
We are finding things that certainly have spiral arms, so they've got old stars in.
So that's a great result.
We were jumping up and down when we discovered that.
We've actually discovered 10,000 of these red spirals.
And many more blue ellipticals as well.
Many more.
But the absolutely fascinating thing we discovered is that, as you went into these clusters, the number of red spirals, so the number of these things which have spiral arms but don't have the colours of other spirals, the number of those increase.
What you can say definitively is these red spirals live in clusters.
They don't live on the outskirts, they are mostly in the clusters.
That really is pointing to an environmental effect, where the spiral's blue on the outskirts, and as it comes into the cluster what we think is happening, and this comes back a little bit to the Voorwerp object that we talked about earlier, is that around the spiral can be a cocoon of gas.
And you're not seeing it.
But that cocoon of gas is feeding the star formation.
So, as the spiral comes into the cluster, that cocoon of gas is blown off by a wind.
And so what's happening is there's no cocoon of gas left over.
So no fuel.
No fuel.
And so what we like to use in astronomy, we use wonderful phrases, like we believe that galaxy has been either "starved" of its gas or it's "strangled", OK? So what happens is that the star formation shuts down and that spiral becomes red.
And then maybe the final part of the story for our poor spiral heading into the big city for the first time is that we know that one way to produce ellipticals is to crash two spirals together.
We see examples of this happening in galaxies.
We have a huge sample of merging galaxies.
Antennae.
The Antennae or the Mice are things that are probably on their way to forming ellipticals.
So maybe after they've gone into the big city and been strangled, mugged We should be mugging the galaxies! Then they'll bash into one of their colleagues and end up as a nice elliptical sitting exactly where we want ellipticals to be.
I got hooked and I began doing it in a very mild way, as you know.
You say you're calling for volunteers now.
Suppose there's someone watching us at the present moment and they'd like to join in.
What do they do? They go to our website, which is galaxyzoo.
org, where very, very shortly a whole new task will be set for our army of volunteers.
Oh, dear! What's this one? We realised a couple of things.
One is that by comparing to professional classifications, our volunteers are really good at this.
We saw that when we tried to classify galaxies.
It's much better to get the public to do it.
Astronomers have learnt to ask more complicated questions.
How tightly wound are the spiral arms? Actually, how many spiral arms are there? And how big is this bulge at the centre? Is there a bar at the centre, or do the spiral arms go all the way into the centre? That's a debate that's been happening for our Milky Way for years.
Yes.
We're going to take the quarter of a million brightest - and therefore prettiest, by the way - galaxies in the Sloan, and we're going to ask people to give us detailed classifications of those, not by learning classifications but by answering a series of questions.
And then the other thing we realised is that we CAN find these unusual objects.
We talked about the Voorwerp.
There are all sorts of examples.
We're going to make it easier for people to tell us when they find something unusual.
The feedback we've had on the forum from e-mails has been incredibly positive, and it's been very nice to hear that people really do enjoy astronomy.
A lot of people think the public aren't interested.
But I think we've proved them wrong by the amazing success of Galaxy Zoo.
And there's something that they can really do and be useful at the same time.
I had a go at it.
I've been observing the moon.
I don't know anything about galaxies at all! But I've thoroughly enjoyed doing it.
And you'll get to carry on, then.
Absolutely, and we've got plans in place for at least the next three years.
And we've got plenty of work for 160,000 people and many more.
Come back before very long and tell us what the latest results are.
And congratulations to you, Chris, for starting it and to you for carrying it on.
So it's a great business.
Well now, we've been talking about galaxies.
You can see some with small telescopes or even binoculars, and outside my observatory, Pete Lawrence is there to have a look at some of them.
As we head in to September, there are some fantastic galaxies on view, and we have the virtue of having one of the brightest in the entire night sky, M31, the Andromeda galaxy, a beautiful spiral galaxy in the constellation of Andromeda.
Now, we can find M31 quite easily.
We can use an old friend, which is the Great Square of Pegasus.
At this time of year, the Great Square of Pegasus is rising in the hours before midnight in the east, so it's fairly easy to find.
If we can locate the Great Square, locate the two stars at the top of the square and extend them to the left by about the same distance as the square side.
Go up slightly from that point and you'll come to another star, which is about the same brightness as the stars in the Great Square, and this is Beta Andromedae, and it's a key star for finding the galaxies which I shall be talking about in a moment.
Now, if you turn ninety degrees going up from Beta Andromedae, you'll come to fainter star, which is known as Mu Andromedae.
Keep going up again and you'll come to another star, which is even fainter still, which is Nu Andromedae.
And if you can find Nu Andromedae, the galaxy M31 is just above that.
To the naked eye, in dark skies it looks very obvious.
It's an elongated smudge of light.
In fact, it's a bit of a tease, but I'll come back to why in just a moment.
If you've got a pair of binoculars or a telescope using a low power, if you look at M31 you actually get three galaxies for the price of one, because very close to the core of M31 there are two elliptical galaxies, which are actually satellites of M31 itself, they're actually in orbit around the core of M31.
Now, these two elliptical galaxies actually look slightly different to one another.
If you can locate the one which is due south - it's about a third of a degree due south of the centre of M31- that's known as M32.
It's quite bright, and if you look at it with a telescope, you start increasing the power, you'll see that it looks just like a ball of stars.
It looks like a fuzzy star, actually.
The other one is NGC205, and to find NGC205 you have to go from M32, through the centre of the core and up and slightly to the right.
A little bit further out this time, about half a degree.
Again an elliptical galaxy, but this time it's actually slightly elongated.
But M31 is a spiral galaxy.
If you look at it with a pair of binoculars or a telescope using a low power, what you're most likely to see is just a larger version of what you can see with the naked eye.
And there's a good reason for this, because the fuzzy patch you see with the naked eye is actually just the core of M31.
The spiral arms are there - they extend out much further - but you can't actually see them.
They're too dim.
And there's another problem with M31, in that it's actually tilted over to us by quite a large angle, about 77 degrees, and that means we see it quite obliquely on.
So even if we could see the spiral arms, it would be difficult to see much structure.
To see a spiral galaxy in its full glory, we need to find one which is more or less face-on to us.
And fortunately, there is one very close by.
In fact, if we go back to M31, join a line from M31 to Beta Andromedae - this is the star we found earlier - and then extend it for the same distance again, going downwards this time, the end point of that line marks the position of another famous spiral galaxy, M33 in the constellation of Triangulum, the Triangle.
In fact, it's known as the Triangulum Galaxy.
Now, this is a wonderful object.
But if you look at it with a telescope using a reasonable magnification, you probably won't see anything at all.
It's large and it has a low surface brightness.
What happens is you're looking right through the galaxy.
What you need to do to see it is to use a low power, and a pair of binoculars is ideal or a low-power eyepiece.
If you do this, you'll be able to see that it has an elongated, smudgy appearance.
But if you keep staring at it, you may be able to see the structure start to form in those spiral arms.
You may be able to pick it out.
It looks like some sort of fantastic celestial Catherine Wheel, if you like.
Now, M33, M31 and its two companion elliptical galaxies are going to be up for several months yet, so if you have a telescope, a pair of binoculars or even just your eyes, go outside and look at these fantastic objects.
They're just wonderful.
Well, that's good advice.
Now, back indoors, and we're joined by Martin Mobberley.
Now, on August 1st we had an eclipse of the sun.
It was only a small partial eclipse here.
I did take a picture of it, but not very spectacular.
But Martin was in the tack of totality, so, Martin, can you tell us where you were and what you saw? Well, Patrick, I'm sure you'll agree that total solar eclipses are just about the most awesome spectacle that you can possibly see.
For this particular eclipse, I was in a place called Novosibirsk, which is Russia's third-largest city, not far from the Russia-Chinese border, and we had a spectacular two minutes nineteen seconds of totality.
I am green with envy! Well, the trouble with all these eclipses is they're spectacular, they're awesome, but the time just flies by.
The two minutes nineteen seconds just seems like about 30 seconds, and you wonder where the time went.
But the most dramatic pictures I've seen of this eclipse were by the master, the undisputed master of coronal imaging, Miroslav Druckmuller, who's from the University of Technology in Brno.
This is incredible, this picture.
And his pictures are just awesome.
He takes about 20 pictures of various exposures, combines them, flat-fields them, dark-frames them, aligns them and spends weeks processing the images.
And this is the sort of spectacular result he gets.
Well, I envy you.
And luckily, there's another eclipse next year, another totality.
You will see it, so will you, Chris.
Very sadly, I shan't.
Thank you, Martin.
Thank you.
On other news next Phoenix on Mars has been doing great things.
Yes, we're just at the end of the third month of its time on Mars, and it's been working very hard indeed, firstly to get samples from the soil into its ovens, an instrument called Tiga, which can then heat them and we can look at the chemical composition of the Martian soil.
Phoenix has got three very important samples already into its ovens.
It's had one from the surface, one from the ice layer they discovered just five centimetres underneath that surface and now in the last month one from just in-between.
So we have a good sense of how the properties of the Martian soil change in this exotic location.
Phoenix also has a microscope, half of the Mecca package.
They've been taking a close look at the soil and also using something called an atomic force microscope to get very detailed images of individual Martian dust grains.
So, observers have always seen dust on Mars - you see dust storms, we've seen dust devils from the rovers.
Well, now we can see the dust grains themselves, and that's a fantastic result.
They've been looking at the chemistry of the soil, too.
Yes.
The results are confusing.
We've known for the last couple of months that the soil is alkaline, but the chemistry is more complicated than that.
We've been told that there are chemicals called perchlorates there.
It doesn't matter what a perchlorate is.
But it's a complicated chemistry, so it's going to take some time to understand those results.
And time is something that Phoenix doesn't have.
No! It's been in the Martian arctic, so it's had midnight sun until now, but just a week ago there was the first sunset as seen from Phoenix.
There's an amazing image of it.
But that mean that Phoenix, which depends on solar power, is going to be able to do less and less.
They've got about a month of good, hard-working robotic arm time left.
So the team will want to make the best use of that time, because they're seeing frost forming on the surface overnight already.
Eventually, that frost will cover the lander and Phoenix won't survive the Martian winter.
No.
I fear Phoenix cannot survive through the Martian nights.
Let's go out now to the further reaches of our own solar system, to Saturn and that weird moon Enceladus.
And the Cassini probe made another close fly-by, and it has become more and more amazing.
The tiger stripes near the pole, they're where the fountains come out.
That's right, and these seem to be the source of Enceladus's most intriguing feature.
These are the Fountains of Enceladus, which shoot out from one end of this small moon that has no right to have any activity on it whatsoever.
Cassini flew close to the surface, just a few tens of kilometres, and they had to invent a whole new mode of imaging to be able to capture these spectacular images.
What you're seeing here is a series of V-shaped fissures - valleys, I suppose, if you like - about three hundred metres deep, and it's from these that these eruptions are happening.
The sides of the valleys are covered in some sort of fine material.
We're not sure what that is yet.
There are these blocks of ice the size of houses surrounding either side of the fissures.
So what all of this means I've no idea, but this is the key to Enceladus's mystery.
Well, in my view, the Fountains of Enceladus are the most mysterious things we've found yet.
And one more thing - Fermi.
Yes, a new space telescope which used to be known as GLAST.
It was launched a few months ago, and looks at the high-energy part of the sky.
So it's been named after Enrico Fermi, the great pioneer of high-energy physics.
And we have the first map from it.
The stripe you can see is the Milky Way, and then there are three or four other objects.
Three of those are pulsars and one is a strange active galaxy called a blazar.
And Fermi's mission will be to look at these active objects and try and understand them and to catch the biggest bang since the beginning of the universe, gamma-ray bursts.
Well, it certainly has much to tell us.
And of course, we'll keep everyone up to date.
Chris, Martin, thank you very much.
When I come back next month, we'll talk about the autumn sky and join in an autumnal equinox star party.
Until then, good night.
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