Sunspots And Climate Change Deniers

For over a week now Honolulu, Hawai'i, has been playing host to the 29th General Assmebly of the International Astronomical Union. Sadly this is not a precursor to Starfleet but it is still rather exciting nonetheless. The Union represents over ten thousand astronomers and the triennial meeting is always a wellspring of cutting edge space science.

On August 7th they released information about the longest continuous experiment in existence which dates back to observations taken by Galileo Galilei. It was all to do with sunspots. You see, from 1645 to 1715 there was what is sometimes referred to as a mini ice age; whist this is a factually poor description of what happened it is certainly true that winters were harsher during this period. This coincided with a prolonged trough in solar activity known as the Maunder Minimum and so it was that we have assumed for several centuries that the former was caused by the latter. Solar activity is measured by counting the number of sunspots visible on the surface of the sun at any given time: the more spots the more activity. More recent data, however, has started to contradict this hypothesis and so the whole model has come under increasing scrutiny.

This is significant because if solar activity has been steadily increasing for the past 300 years then it could go some way to explaining the warming of the planet that is such a pressing concern today. It would also mean that if the warming isn't anthropogenic (manmade) in origin then our various warnings about carbon emissions and heavy industry are incorrect. I know I personally have met people, let's call them climate change deniers, who say that us puny humans are incapable of affecting a whole planet in this way, and, that solar activity explains everything so it's fine to have a coal powered car built from amazonian mahogany. Well, the new data, which reconciles a long running discrepancy in the two ways we can count sunspots, shows that solar activity does not in fact correlate with the steady increase in global temperature that we have been observing since the beginning of the Industrial Revolution. To quote them:

'[these results] make it difficult to explain the observed changes in the climate that started in the 18th century and extended through the industrial revolution to the 20th century as being significantly influenced by natural solar trends.'

Notice that there is wriggle room in that statement, but that is because it was issued by scientists who understand that new data can always change your theory. As it goes, that is actually quite a strong statement and would be a blow to the climate change deniers if their position was in any way based on reality. So there you have it, one more line of evidence to support anthropogenic global warming, one less place for the climate change deniers to hide. Will it change any of their minds? Not a chance.

Hand drawn by Galileo himself this is one of a series of drawings that show the
progress of sunspots across the surface of the sun with time.

When You Wish Upon A Star

Asides from being useful for bringing inanimate puppets with a propensity for fibbing to life, shooting stars are also rather exciting to watch. This is just as well because we are about to hit the peak for the Perseid meteor shower. But what actually is a shooting star? Hale-Bopp; Swift-Tuttle; Halley's, these are all comets and comets all have something in common. Comets are effectively giant, dirty snowballs and as they sail around the solar system bits of water ice and rock and other debris stream off behind them, this is especially the case as thy warm up when they pass near to the sun. This cometary debris just sort of hangs about in the vacuum of space until an unwitting planet like ours happens to come piling through it.

A shooting star, then, is actually a tiny piece of comet that is entering our atmosphere and burning up as it does so due to the extreme heat produced as it drags through the air. The Perseid meteor shower is called such because the debris from the comet all appears to be entering the sky around about the constellation of Perseus. People much more clever and talented than I are able to take multiple images of Perseid meteors and overlay them, these combined images make it much more obvious what I mean when I say they radiate out of the Perseus constellation; see below.

Keeping the Greek theme going, comets are so called because back in the day the Greeks thought of the streaming tail of a comet as flowing long hair. Their word for that is κομᾶν which morphed into Κομήτης their word for comet, which my Greek buddy Anastasia reliably informs me is pronounced komiti.

The comet Swift-Tuttle, which I mentioned above, is actually quite pertinent here. It is the tail debris of this comet that we pass through every August which gives us the Perseid meteor shower, a phenomenon that astronomers have been observing for over two thousand years now. I was wondering if the meteor shower would diminish in magnitude each year as we slowly but surely clear the area of debris as we keep going through it, but then it gets replenished once Swift-Tuttle hurtles through every 133 years. I've struggled to find any information on this so I've tweeted a couple of proper astronomers to try to find out. I'll update this post if they get back to me.

In the meantime, if you're in the UK, look to the northeast in the evening and get some wishes ready.

**UPDATE: Astrophotographer extraordinaire and Sky At Night presenter Pete Lawrence got back to me about my theory and I'm totally wrong. The earth hardly removes any of the debris compared to how much the comet sheds and it does indeed replenish it as it orbits so, if anything, perhaps the Perseids will get more intense with time.**

Image courtesy of NASA

A-Hazing New Pluto Picture

Exciting news Plutophiles! Last Friday NASA had another Pluto press conference and in it they released the latest images from New Horizons, the most amazing of which was this beauty below.

This is an image taken by the probe after it has sped past Pluto. It is looking back at the night side of the world 7hrs after closest approach. The halo around the edge is the hazy atmosphere backlit by the sun. It was only recently that we even became sure that Pluto had an atmosphere; the data here shows that it does indeed have one, that it extends about 80 miles above the surface and that it is comprised mainly of nitrogen. But the haze is actually the interesting bit. The haze is made up of complex hydrocarbons, like ethylene and acetylene, which are created when ultraviolet light from the sun interacts with methane gas in the atmosphere. The UV light in turn changes the hydrocarbons into tholins, these fall back to the surface and are what gives the dwarf planet its now distinctive dark patches.

Pluto has once again, however, thrown up a mystery. These hazes are created by the hydrocarbons condensing into little ice crystals, but it was thought that Pluto would be too warm for this to happen at a height of above 20 miles or so; yet we're seeing haze as high as 80 miles and we have absolutely no idea how. Some new ideas are needed to come up with a satisfactory explanation for this, but that's a good thing; if the answer to your question doesn't throw up at least a couple of new questions then you're not doing it right and that, Science Fans, is one of the exciting things about the frontiers of science.

New Earth-like Planet Discovered

Last Thursday NASA called a press conference. It was a bit out of the blue but we were given a heads up that it had to do with Kepler so everyone knew they would be announcing a newly discovered earth-like planet; and so it came to be. Kepler, of course, was the planet hunting satellite named after Johannes Kepler the German mathematician and astronomer. Kepler worked using the transit method; it would stare at thousands of suns and look for tiny dips in the levels of brightness, this could indicate that a planet had passed in front of, or transited, the star and temporarily blocked some of its light. If a dip was found to have a regular pattern then there was a good chance it was a planet. Using this method Kepler has found many thousands of candidate planets, 1879 of which have been confirmed at time of writing.

Thursday's announcement of planet Kepler 452b was a little different as they claimed to have found the exoplanet most like our own. The planet is a rocky one about 60% larger in size than the earth but about 5 times more massive, so it's likely to be very volcanic with quite a dense atmosphere. Its sun is 50% or so larger than our own and a billion years older so it's likely to throw out a lot more heat than we're used to experiencing. This combination could actually mean that conditions on the planet are too harsh for life to exist, certainly complex life anyhoo.

Before this announcement the most earth-like planet discovered to date was Kepler 186f. This is a rocky world no more than 10% larger than us orbiting a red dwarf star. Even at midday this world would only be about as light as sunset here on earth, despite this I think 186f actually remains the most earth-like planet we have yet discovered. Sorry Kepler 452b.

Below you can see the four most earth-like planets and their stars discovered by Kepler so far with the earth for comparison.

Image courtesy of NASA

Very Bright Light, Very Big Number

Researchers at the Kavli Institute in Beijing have reported potentially finding the brightest supernova ever seen. If correct this exploding star was about 600 billion times brighter than the sun; that's about 100 times brighter than your common to garden supernova and 2.5 to 5 times brighter than the previous brightest one depending upon who you ask. I have to caveat all this as it is not certain yet that it even was a supernova, it could also have been caused by the destruction of a star that passed a bit too close to a black hole; further observations over the coming months should help us find out. In any case, the explosion happened 2.8 billion years ago, about 700 million years before multi-cellular life evolved on earth.

Oh, and I calculated the brightness to be the equivalent of 2.3034e+36, or 2,303,400,000,000,000,000,000,000,000,000,000,000 or 2.3 undecillion 100 watt lightbulbs.

Image courtesy of ESO

Pluto: Why So Smooth?

Fantastic news, Science Fans! It took it's sweet time (about 4.5 hours at the speed of light) but we finally got the first data from the New Horizons spacecraft. And even better than that: there is already a genuine mystery to puzzle out. So far we have two great pictures and some data on methane density.

The first picture, below, is of Pluto itself; it is a close up of the now famous 'heart' region. For scale, some of these peaks are about 11,000 feet high, which is comparable with mountains here on earth. What is interesting is that there are hardly any craters at all in this picture. It's very unlikely that this is because Pluto hasn't been hit by any meteors so we have to conclude that it means this surface is a very new one, and when we say very new here we mean about 100 million years old. Therefore, in the recent geological past, a process must have occurred to create this new surface. Generally this could be achieved by the planet being geologically active, like the earth is, with earthquakes and volcanoes and such churning up the place and destroying any evidence of crater impacts; or, a very large mass nearby can literally cause tides in the rock that cause them to grind and move and create heat again destroying any impact craters that might be around. The problem is that Pluto is both too small and cold to be geologically active and there is nothing large enough nearby to create tidal forces. We have a mystery.

The next picture, below, is of Pluto's largest moon, Charon, and here we see the same puzzling phenomenon. It's surprisingly smooth, there aren't all that many obvious craters; conjure (or Google) an image of our pock marked moon for comparison and the lack of craters will be much more obvious. The same argument applies here as to Pluto and we simply don't yet have an explanation. I guess it's not completely impossible that just by chance the two bodies have avoided impacts for several billions of years, but given that we know the Kuiper belt, of which Pluto is a part, is chock full of rocks and potential meteors this really does seem extremely unlikely. Do not, however, be disheartened. If there's one thing that scientists like it's a mystery. If you ask a question and the answer doesn't throw up at least a dozen new questions then you're doing it wrong.

These images are just the first tranche of what will ultimately be a deluge of data, frustratingly most of that is still on the New Horizon's craft and it will take weeks or even months for it all to be beamed back home. These initial images will have to keep us busy for a little while but one thing is for certain; we have lots of new and exciting discoveries to make about our former planetary cousin.

Pluto Revealed

I, for one, am excited. 3,462 days ago a rocket was launched carrying the New Horizons spacecraft. Its mission was to conduct the first ever flyby of the planet Pluto. Yes, that's right, the planet pluto. Back then it was still a planet but as every 8 year old but few 38 year olds know Pluto was reclassified as a dwarf planet in 2006 and we now have a solar system with 8 planets in it. The problem was that we started to find a lot of other objects out there that were about the same size as Pluto so, if we were going to keep pluto, then we would have to make room for these other objects too and very soon we might have a solar system with a couple of dozen planets in it. Good luck getting the 8 years olds to memorise all those.

Anyhoo, Pluto being so very small (only a couple of thousand kilometres across) and receiving only about one thousandth of the sunlight we enjoy it is quite difficult to see. Even when we point the mighty Hubble space telescope at it we fail to get images with any great detail in them. The image on the right was the best we had until new Horizons started edging closer in the last few weeks.

Then last weekend, at a distance of about 1 million miles from Pluto, the image below was beamed back from 3 billion miles away. The increase in resolution is marked and will have the Geology, Geophysics and Imaging nerds at John Hopkins university very excited; as it will all of us interested in going boldly where no one has ever gone before. And the best part? It's only going to get better. The craft will pass within 8,000 miles of the planet's surface today and, asides, from all the cool science that will be done, should take some pretty awesome pictures before speeding off into the outer solar system at 50,000 miles per hour.

Images courtesy of NASA

The Milky Way

On my first night of this particular trip to Romania last summer I got excited. As we were driving to my girlfriend's dad's house (personally I'd call it a farm), I looked out of the car window and saw stars. Not just a few like you get in London, but hundreds and hundreds of them; maybe a couple of thousand. And stretching out across the heavens, as clear as day, was the Milky Way. This wasn't the first time I'd seen it; I'd seen the galactic disc in lots of different places around the world and I've even been able to see it in the UK a few times; but this time I knew that I was going to be here for a couple of weeks and there should be plenty of opportunities to get some good pictures. I was excited.

One night when I had a spare hour or two I took the camera out onto the road beside the farm, I knew there wouldn't be traffic any time soon, and started taking a few tester pictures. First of all I decided to try and get a shot of stars with the landscape included for perspective. There were trees and a few farm buildings across the way. It wasn't easy as there was the odd streetlight here and there that made the exposure difficult to get right. The results weren't great but I wasn't too bothered as I knew this was just the preamble to the Milky Way shots I was going to get later.

Having got a fairly mediocre picture I moved round to the side of the farm where it was even darker and there were fewer lampposts. Now I was aiming almost directly up in the air to try and get a picture of just the Milky Way with nothing terrestrial in frame. The first few attempts were promising and not too long later I had the shot I had been waiting for. It looked great. The galaxy was clearly defined arcing right through the middle of the frame, the stars were bright and pin sharp and I knew I had a keeper. I was excited to think how it would look once I'd processed it a little to make it even clearer once I got back to Blighty. You can see the finished result below.

Pardon? What's that you say? You can't see anything? Am I sure I uploaded the right picture? Yes, I'm sure. Hmmmmm.... The problem seems to be that what I saw on the back of my camera that night was not representative of the data the camera captured. I can't really explain what went wrong but it goes without saying that once I got home I was very disappointed to see the result as, as you can see, it's rubbish. There is basically nothing there. I tried to process it every way I knew how but it seemed beyond rescue. I was gutted. I have posted it here anyway mostly just as a warning, I suppose. You can't always trust exactly what you see in camera. My advice would be to make sure you always check the histogram, especially if you're working in extreme light conditions, as this should give an unbiased account of the data you've captured; and keep taking pictures, even if you think you've got 'the one'. I hope you have more luck than I did.

The Sun: Part 3 - Helioseismology

Okay, I mean it this time. This time I'm definitely going to write a post about helioseismology; no distractions. This will be my third and final attempt; my first try ended up being a general overview of the sun and its structure, my second attempt wound up being about the potential of nuclear fusion here on Earth. But now, according to the Rule of Threes, I will finally keep my promise.

For the last couple of weeks I have been reading as much as I can about the now well established field of helioseismology and the first thing I had to learn was what it even is. In my innocence I thought that there might be quake type events happening in the sun but that turns out not to be the case. If you think about it for a while, though, you can see why this would be wrong. The Earth has many different components to it, the most relevant being the lithosphere which is made up of the tectonic plates of the surface and the top most part of the upper mantle. Here, where two continents meet, you might have one subducting under another or perhaps they will be grating against each other in opposite directions. In this situation it's possible that they might get a bit stuck and every now and then they will suddenly slip causing an earthquake. Asides from the damage we're all too used to seeing on the surface this will also cause sound waves to propagate through the Earth. These sound waves will move through different substances in different ways dependent upon their properties and so you can use this to study the internal structure of, in this case, the Earth. This is a key part of what seismology is here on the third rock but we can use the same principals with the sun; there, however, the waves aren't caused by solid rock but by shifting plasma densities.

Here you can see the ripples of a sunquake radiating out from its source. In just one hour the ripple travels a distance equivalent to 10 earth diameters.

Plasma, which is basically what the sun is, is a gas that has been stripped of electrons. The sun is not a boring, uniform, unchanging sphere of plasma but a highly active and dynamic one. It is hotter at its centre than it is nearer the surface and this can result in hotter, less dense plasma rising higher amongst cooler, less dense plasma. My best interpretation of what I've read, and I could easily be wrong, is that this causes a sound wave to be produced, perhaps through friction but don't quote me on that. Either way a sound wave is created. This wave then propagates and can be detected by instruments aboard the Solar Dynamic Observatory (SDO) and the Solar Heliospheric Observatory (SOHO), both satellites orbiting the sun. The waves tend to have frequencies of 1-5 microHertz, or around five minutes and amplitudes of hundreds of kilometres. Given this we can know at what sort of speed they should move and where there are deviations from this we can infer the density of the medium through which they're moving. This has given us a great level of detail about the internal structure of the sun.

Like all good theories though, it needs to be tested for accuracy and this has been done quite exquisitely. A few years ago scientists were able to detect these sound waves some 60,000km below the surface of the sun, they then predicted that this would result in the production of some sunspots at a given location. Two days later, sure enough, the sunspots appeared. You can see a video of it happening here:

This is super awesome. Not just because it represents an advance in our understanding of an obscure branch of solar science but because it has practical implications for us here on Earth. How so? Well, the magnetic field of the sun is particularly intense where sunspots are formed and at the end of the video, as the rotation of the sun begins to take the activity from view, you can see that vast arcs of plasma, greater than the size of the Earth itself, are formed along the lines of the magnetic field. The sunspots are at the bases of the arcs where they are anchored to the surface, but if they are strong enough then these arcs can snap free and hurl matter out into the solar system. Small events are referred to as solar flares and larger ones are called coronal mass ejections (CME). These can be highly significant as they can fling billions of tons of matter into space at a time. If the Earth happens to get in the way of this then you can expect a pretty impressive display by the aurorae at both poles as the matter interacts with our own magnetic field. Nothing wrong with that. If it is an especially large CME, though, then this could play havoc with electrical equipment all over the planet.

In late summer of 1859 the largest CME on record was observed. Known as the Carrington Event, it caused the aurorae to be seen as far south as the Caribbean and as far north as New Zealand. It also, however, caused widespread electrical damage. Telegraph stations across the globe went down, some operators were electrocuted, pylons sparked and some devices that were turned off began to operate. This was at a time when we were just at the beginning of the electrical age, if this happened to us today then it could be potentially devastating. It has been estimated that the cost to the United States alone would be in the region of 0.6-2.6 trillion dollars. That is a solar storm we do not want to happen, the problem is that, eventually, it will. Estimates say that there is a 12% chance that there will be another by the year 2022 and that it is all but guaranteed by the end of the century. So it's not a matter of if but when.

Here is where the research comes in. That CME took just 17 hours to reach us from the sun. That is not much time to enact emergency procedures to protect our electrical systems, not that we actually have any such procedures as of yet. With this research though it would be possible to have at least a couple of days notice which should be plenty of time to prepare the world saving weeks of disruption and trillions of dollars - just as soon as we know how to prepare.

Perhaps the most important message to take home from this is that you never know where the benefits of scientific research might lead. There are certain groups of people cough politicians cough cough who want scientists to solve certain specific problems and will only fund research aimed at doing so. Sometimes this can work, but sometimes it won't, and what should never be discounted is good old fashioned, curiosity driven, blue sky research where you fund a scientist simply to figure something out because it's interesting. This has led to many of the most significant breakthroughs in human history, perhaps most notably in the creation of the internet. In this case a bunch of guys sat around staring at the sun, so to speak, quietly developing our notion of space weather and now we have a way of potentially saving our society as we know it. This is just one of the reasons I love science.